This report provides the results of a detailed Level II analysis of scour potential at structure \nTOPSTH00570038 on Town Highway 57 crossing the Waits River, Topsham, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.
\nThe site is in the New England Upland section of the New England physiographic province \nin east central Vermont. The 37.3-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is predominantly pasture while the \nleft bank upstream is suburban.
\nIn the study area, the Waits River has a sinuous locally anabranched channel with a slope of \napproximately 0.01 ft/ft, an average channel top width of 76 ft and an average bank height \nof 6 ft. The channel bed material ranges from sand to cobble with a median grain size (D50) \nof 57.2 mm (0.188 ft). The geomorphic assessment at the time of the Level I and Level II \nsite visit on August 28, 1995, indicated that the reach was considered laterally unstable due \nto cut-banks upstream, mid-channel bars and lateral migration of the channel towards the \nleft abutment.
\nThe Town Highway 34 crossing of the Waits River is a 34-ft-long, one-lane bridge \nconsisting of one 31-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, March 28, 1995). The opening length of the structure parallel to the bridge \nface is 30.4 ft. The bridge is supported by a vertical, stone abutment with concrete facing \nand wingwalls on the right and by a vertical, concrete abutment with wingwalls on the left. \nThe channel is skewed approximately 0 degrees to the opening and the opening-skew-to-roadway is also zero degrees.
\nA scour hole 2.0 ft deeper than the mean thalweg depth was observed towards the left bank \nunderneath the bridge. The only scour protection measure at the site was type-2 stone fill \n(less than 36 inches diameter) along the left bank upstream, in the upstream left wing wall \narea, along the left abutment, at the downstream end of the right abutment, and in the \ndownstream left wing wall area. There is type-3 stone fill (less than 48 inches diameter) in \nthe downstream right wing wall area. Additional details describing conditions at the site are \nincluded in the Level II Summary and Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). \nTotal scour at a highway crossing is comprised of three components: 1) long-term \nstreambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction \nin flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.
\nContraction scour for all modelled flows ranged from 1.6 to 5.2 ft. The worst-case \ncontraction scour occurred at the 100-year discharge. Abutment scour ranged from 9.8 to \n18.5 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97649","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Striker, L.K., and Boehmler, E.M., 1997, Level II scour analysis for Bridge 38 (TOPSTH00570038) on Town Highway 57, crossing Waits River, Topsham, Vermont: U.S. Geological Survey Open-File Report 97-649, iv, 51 p., https://doi.org/10.3133/ofr97649.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":175840,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97649.GIF"},{"id":279704,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0649/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Topsham","otherGeospatial":"Waits River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.375,44.0 ], [ -72.375,44.125 ], [ -72.25,44.125 ], [ -72.25,44.0 ], [ -72.375,44.0 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a646c","contributors":{"authors":[{"text":"Striker, Lora K.","contributorId":41481,"corporation":false,"usgs":true,"family":"Striker","given":"Lora","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":240566,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240567,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49976,"text":"ofr97651 - 1997 - Level II scour analysis for Bridge 32 (HUNTTH00220032) on Town Highway 22, crossing Brush Brook, Huntington, Vermont","interactions":[],"lastModifiedDate":"2013-12-18T10:25:26","indexId":"ofr97651","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-651","title":"Level II scour analysis for Bridge 32 (HUNTTH00220032) on Town Highway 22, crossing Brush Brook, Huntington, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nHUNTTH00220032 on Town Highway 22 crossing Brush Brook, Huntington, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.
\nThe site is in the Green Mountain section of the New England physiographic province in \ncentral Vermont. The 5.7-mi2\n drainage area is in a predominantly rural and forested basin. \nIn the vicinity of the study site, the surface cover is forest except on the downstream right \noverbank which is pasture.
\nIn the study area, Brush Brook has an incised, straight channel with a slope of \napproximately 0.05 ft/ft, an average channel top width of 58 ft and an average bank height \nof 6 ft. The channel bed material ranges from gravel to boulder with a median grain size \n(D50) of 127 mm (0.416 ft). The geomorphic assessment at the time of the Level I and Level \nII site visit on June 25, 1996, indicated that the reach was stable.
\nThe Town Highway 22 crossing of Brush Brook is a 36-ft-long, one-lane bridge consisting \nof one 34-foot steel-beam span and a timber deck (Vermont Agency of Transportation, \nwritten communication, December 12, 1995). The opening length of the structure parallel to \nthe bridge face is 35.7 ft. The bridge is supported by vertical, concrete abutments with \nwingwalls on the left. The channel is skewed approximately 50 degrees to the opening \nwhile the measured opening-skew-to-roadway is 15 degrees.
\nA scour hole 1.0 ft deeper than the mean thalweg depth was observed along the left \nabutment and downstream left wingwall during the Level I assessment. The only scour \nprotection measure at the site was type-2 stone fill (less than 36 inches diameter) along the \nupstream right bank. Additional details describing conditions at the site are included in the \nLevel II Summary and Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). \nTotal scour at a highway crossing is comprised of three components: 1) long-term \nstreambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction \nin flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.
\nContraction scour for all modelled flows ranged from 0.0 to 0.2 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 6.4 to \n10.2 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97651","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Burns, R.L., 1997, Level II scour analysis for Bridge 32 (HUNTTH00220032) on Town Highway 22, crossing Brush Brook, Huntington, Vermont: U.S. Geological Survey Open-File Report 97-651, iv, 48 p., https://doi.org/10.3133/ofr97651.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":176955,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97651.GIF"},{"id":279702,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0651/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Hungtington","otherGeospatial":"Brush Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b19e4b07f02db6a7c7c","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240569,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":49979,"text":"ofr97658 - 1997 - Level II scour analysis for Bridge 17 (RIPTTH00180017) on Town Highway 18, crossing the South Branch Middlebury River, Ripton, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T16:07:56","indexId":"ofr97658","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-658","title":"Level II scour analysis for Bridge 17 (RIPTTH00180017) on Town Highway 18, crossing the South Branch Middlebury River, Ripton, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nRIPTTH00180017 on Town Highway 18 crossing the South Branch Middlebury River, \nRipton, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, \nincluding a quantitative analysis of stream stability and scour (U.S. Department of \nTransportation, 1993). Results of a Level I scour investigation also are included in \nAppendix E of this report. A Level I investigation provides a qualitative geomorphic \ncharacterization of the study site. Information on the bridge, gleaned from Vermont Agency \nof Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II \nanalyses and is found in Appendix D.
\nThe site is in the Green Mountain section of the New England physiographic province in \nwest-central Vermont. The 15.5-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is forest except on the upstream left \nbank where it is shrubs and brush.
\nIn the study area, the South Branch Middlebury River has an incised, sinuous channel with \na slope of approximately 0.03 ft/ft, an average channel top width of 86 ft and an average \nbank height of 10 ft. The channel bed material ranges from gravel to boulders with a median \ngrain size (D50) of 111 mm (0.364 ft). In addition, there is a bedrock outcrop across the \nchannel downstream of the bridge. The geomorphic assessment at the time of the Level I \nand Level II site visit on June 10, 1996, indicated that the reach was stable.
\nThe Town Highway 18 crossing of the South Branch Middlebury River is a 61-ft-long, one-lane bridge consisting of one 58-foot steel-beam span (Vermont Agency of Transportation, \nwritten communication, November 30, 1995). The opening length of the structure parallel \nto the bridge face is 56.8 ft. The bridge is supported by vertical, concrete abutments with \nwingwalls. The channel is skewed approximately 40 degrees to the opening while the \ncomputed opening-skew-to-roadway is 30.
\nA scour hole 1.25 ft deeper than the mean thalweg depth was observed along the right \nabutment and the downstream right wingwall during the Level I assessment. The scour \nprotection measures at the site include type-2 stone fill (less than 36 inches diameter) along \nthe left abutment and it’s wingwalls and at the upstream end of the right abutment. Also, \ntype-3 stone fill (less than 48 inches diameter) is along the upstream right wingwall. \nAdditional details describing conditions at the site are included in the Level II Summary \nand Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge is determined and analyzed as another potential worst-case scour scenario. Total \nscour at a highway crossing is comprised of three components: 1) long-term streambed \ndegradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow \narea at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.
\nContraction scour for all modelled flows ranged from 0.1 to 1.1 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 5.6 to \n9.0 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97658","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Burns, R.L., and Medalie, L., 1997, Level II scour analysis for Bridge 17 (RIPTTH00180017) on Town Highway 18, crossing the South Branch Middlebury River, Ripton, Vermont: U.S. Geological Survey Open-File Report 97-658, iv, 48 p., https://doi.org/10.3133/ofr97658.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":175373,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":279699,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0658/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Ripton","otherGeospatial":"South Branch Middlebury River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8239","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240574,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Medalie, Laura 0000-0002-2440-2149 lmedalie@usgs.gov","orcid":"https://orcid.org/0000-0002-2440-2149","contributorId":3657,"corporation":false,"usgs":true,"family":"Medalie","given":"Laura","email":"lmedalie@usgs.gov","affiliations":[{"id":466,"text":"New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240573,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49981,"text":"ofr97661 - 1997 - Level II scour analysis for Bridge 36 (DUXBTH00040036) on Town Highway 4, crossing Crossett Brook, Duxbury, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T14:49:07","indexId":"ofr97661","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-661","title":"Level II scour analysis for Bridge 36 (DUXBTH00040036) on Town Highway 4, crossing Crossett Brook, Duxbury, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure DUXBTH00040036 on Town Highway 4 crossing the Crossett Brook, Duxbury, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.
The site is in the Green Mountain section of the New England physiographic province in north-central Vermont. The 4.9-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover on the upstream left overbank is pasture. The upstream and downstream right overbanks are forested. The downstream left overbank is brushland, while the immediate banks have dense woody vegetation.
In the study area, the Crossett Brook has an incised, sinuous channel with a slope of approximately 0.006 ft/ft, an average channel top width of 55 ft and an average bank height of 9 ft. The channel bed material ranges from gravel to bedrock with a median grain size (D50) of 51.6 mm (0.169 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 1, 1996, indicated that the reach was stable.
The Town Highway 4 crossing of the Crossett Brook is a 29-ft-long, two-lane bridge consisting of a 26-foot concrete slab span (Vermont Agency of Transportation, written communication, October 13, 1995). The opening length of the structure parallel to the bridge face is 26 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 35 degrees to the opening while the computed opening-skew-to-roadway is 5 degrees.
A scour hole 1.5 ft deeper than the mean thalweg depth was observed along the upstream left wingwall and the right abutment during the Level I assessment. Scour countermeasures at the site includes type-2 stone fill (less than 36 inches diameter) at the upstream end of the upstream left and right wingwalls and the upstream left and right banks and road embankments. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.
Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for all modelled flows ranged from 0.0 to 1.7 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 6.4 to 8.3 ft. Right abutment scour ranged from 6.0 to 7.0 ft. The worst-case left and right abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.
It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97661","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., and Degnan, J.R., 1997, Level II scour analysis for Bridge 36 (DUXBTH00040036) on Town Highway 4, crossing Crossett Brook, Duxbury, Vermont: U.S. Geological Survey Open-File Report 97-661, iv, 48 p., https://doi.org/10.3133/ofr97661.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":176148,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97661.GIF"},{"id":279697,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0661/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Duxbury","otherGeospatial":"Crossett Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -73.125,44.375 ], [ -73.125,44.5 ], [ -73.0,44.5 ], [ -73.0,44.375 ], [ -73.125,44.375 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a63d8","contributors":{"authors":[{"text":"Wild, Emily C. 0000-0001-6157-7629 ecwild@usgs.gov","orcid":"https://orcid.org/0000-0001-6157-7629","contributorId":1810,"corporation":false,"usgs":true,"family":"Wild","given":"Emily","email":"ecwild@usgs.gov","middleInitial":"C.","affiliations":[{"id":5081,"text":"Libraries","active":false,"usgs":true}],"preferred":false,"id":240578,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Degnan, James R. 0000-0002-5665-9010 jrdegnan@usgs.gov","orcid":"https://orcid.org/0000-0002-5665-9010","contributorId":498,"corporation":false,"usgs":true,"family":"Degnan","given":"James","email":"jrdegnan@usgs.gov","middleInitial":"R.","affiliations":[{"id":405,"text":"NH/VT office of New England Water Science Center","active":true,"usgs":true},{"id":466,"text":"New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240577,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49984,"text":"ofr97664 - 1997 - Level II scour analysis for Bridge 33 (HUNTTH00220033) on Town Highway 22, crossing Brush Brook, Huntington, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T15:02:59","indexId":"ofr97664","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-664","title":"Level II scour analysis for Bridge 33 (HUNTTH00220033) on Town Highway 22, crossing Brush Brook, Huntington, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nHUNTTH00220033 on Town Highway 22 crossing Brush Brook, Huntington, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.
\nThe site is in the Green Mountain section of the New England physiographic province in \ncentral Vermont. The 8.65-mi2\n drainage area is in a predominantly rural and forested basin. \nIn the vicinity of the study site, the surface cover is forest except on the downstream right \noverbank which is pasture.
\nIn the study area, Brush Brook has an incised, straight channel with a slope of \napproximately 0.04 ft/ft, an average channel top width of 42 ft and an average bank height \nof 3 ft. The channel bed material ranges from gravel to boulder with a median grain size \n(D50) of 76.7 mm (0.252 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on June 26, 1996, indicated that the reach was stable.
\nThe Town Highway 22 crossing of Brush Brook is a 40-ft-long, two-lane bridge consisting \nof one 23.5-foot concrete slab span (Vermont Agency of Transportation, written \ncommunication, November 30, 1995). The opening length of the structure parallel to the \nbridge face is 36.9 ft. The bridge is supported by vertical, concrete abutments with \nwingwalls. The channel is skewed approximately 35 degrees to the opening while the \nopening-skew-to-roadway is 30 degrees.
\nThe scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) \nalong the left and right banks upstream that extended through the bridge and along the \ndownstream banks. Additional details describing conditions at the site are included in the \nLevel II Summary and Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge is analyzed since it has the potential of being the worst-case scour scenario. Total \nscour at a highway crossing is comprised of three components: 1) long-term streambed \ndegradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow \narea at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.
\nContraction scour for all modelled flows ranged from 0.0 to 1.1 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 6.5 to \n14.9 ft. The worst-case abutment scour occurred at the incipient roadway-overtopping \ndischarge. Additional information on scour depths and depths to armoring are included in \nthe section titled “Scour Results”. Scoured-streambed elevations, based on the calculated \nscour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the \nbridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of \nerosive material and a homogeneous particle-size distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97664","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Burns, R.L., and Degnan, J.R., 1997, Level II scour analysis for Bridge 33 (HUNTTH00220033) on Town Highway 22, crossing Brush Brook, Huntington, Vermont: U.S. Geological Survey Open-File Report 97-664, iv, 51 p., https://doi.org/10.3133/ofr97664.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176151,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97664.GIF"},{"id":279694,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0664/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Huntington","otherGeospatial":"Brush Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b19e4b07f02db6a75fa","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240584,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Degnan, James R. 0000-0002-5665-9010 jrdegnan@usgs.gov","orcid":"https://orcid.org/0000-0002-5665-9010","contributorId":498,"corporation":false,"usgs":true,"family":"Degnan","given":"James","email":"jrdegnan@usgs.gov","middleInitial":"R.","affiliations":[{"id":405,"text":"NH/VT office of New England Water Science Center","active":true,"usgs":true},{"id":466,"text":"New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240583,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49987,"text":"ofr97672 - 1997 - Level II scour analysis for Bridge 21 (MONKTH00340021) on Town Highway 34, crossing Little Otter Creek, Monkton, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T14:42:17","indexId":"ofr97672","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-672","title":"Level II scour analysis for Bridge 21 (MONKTH00340021) on Town Highway 34, crossing Little Otter Creek, Monkton, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nMONKTH00340021 on Town Highway 34 crossing Little Otter Creek, Monkton, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix D of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix C.
\nThe site is in the Champlain section of the Saint Lawrence Valley physiographic province \nin northwestern Vermont. The 34.1-mi2\n drainage area is in a predominantly rural and \nforested basin with pasture in the valleys. In the vicinity of the study site, the surface cover \nconsists of pasture. The most significant tree cover is immediately adjacent to the channel \non the right bank downstream.
\nIn the study area, Little Otter Creek has a sinuous channel with a slope of approximately \n0.008 ft/ft, an average channel top width of 92 feet and an average bank height of 6 feet. \nThe predominant channel bed materials are silt and clay. Sieve analysis indicates that \ngreater than 50% of the sample is silt and clay and thus a median grain size by use of sieve \nanalysis was indeterminate. Therefore, the median grain size was assumed to be medium \nsilt with a size (D50) of 0.0310 mm (0.000102 ft). The geomorphic assessment at the time of \nthe Level I and Level II site visit on June 19 and June 20, 1996, indicated that the reach was \nstable.
\nThe Town Highway 34 crossing of Little Otter Creek is a 50-ft-long, one-lane bridge \nconsisting of one 26-foot concrete span and three “boiler tube” smooth metal pipe culverts \nthrough the left road approach (Vermont Agency of Transportation, written \ncommunication, December 15, 1995). The opening length of the bridge parallel to the \nbridge face is 25.1 feet. The bridge is supported by vertical, concrete abutments with \nwingwalls on the right abutment only. The channel is skewed approximately 25 degrees to \nthe opening. The VTAOT records indicate the opening-skew-to-roadway is 20 degrees but \nmeasurement from surveyed data suggests the skew is five degrees.
\nThe scour protection measures at the site were type-1 stone fill (less than 12 inches \ndiameter) on the upstream and downstream embankments of the left road approach and \ntype-2 stone fill (less than 36 inches diameter) surrounding the entrance of each culvert. \nAdditional details describing conditions at the site are included in the Level II Summary \nand Appendices C and D.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge is determined and analyzed as another potential worst-case scour scenario. Total \nscour at a highway crossing is comprised of three components: 1) long-term streambed \ndegradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow \narea at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.
\nContraction scour for all modelled flows ranged from 10.3 to 12.3 feet. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 8.6 to \n22.5 feet. The worst-case abutment scour occurred at the 500-year discharge for the left \nabutment and at the incipient overtopping discharge for the right abutment. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97672","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Boehmler, E.M., and Medalie, L., 1997, Level II scour analysis for Bridge 21 (MONKTH00340021) on Town Highway 34, crossing Little Otter Creek, Monkton, Vermont: U.S. Geological Survey Open-File Report 97-672, iv, 48 p., https://doi.org/10.3133/ofr97672.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":176248,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97672.GIF"},{"id":279691,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0672/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Monkton","otherGeospatial":"Little Otter Creek","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8126","contributors":{"authors":[{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240589,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Medalie, Laura 0000-0002-2440-2149 lmedalie@usgs.gov","orcid":"https://orcid.org/0000-0002-2440-2149","contributorId":3657,"corporation":false,"usgs":true,"family":"Medalie","given":"Laura","email":"lmedalie@usgs.gov","affiliations":[{"id":466,"text":"New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240588,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49989,"text":"ofr97674 - 1997 - Level II scour analysis for Bridge 23 (WALDTH00060023) on Town Highway 6, crossing Stannard Brook, Walden, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T14:06:20","indexId":"ofr97674","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-674","title":"Level II scour analysis for Bridge 23 (WALDTH00060023) on Town Highway 6, crossing Stannard Brook, Walden, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nWALDTH00060023 on Town Highway 6 crossing Stannard Brook, Walden, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.
\nThe site is in the New England Upland section of the New England physiographic province \nin eastern Vermont. The 5.61-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the upstream surface cover is shrub and brushland \nwith some trees. The downstream surface cover is forest.
\nIn the study area, Stannard Brook has an incised, straight channel with a slope of \napproximately 0.02 ft/ft, an average channel top width of 54 ft and an average bank height \nof 9 ft. The channel bed material ranges from gravel to boulder with a median grain size \n(D50) of 64.0 mm (0.210 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on August 8, 1995, indicated that the reach was stable.
\nThe Town Highway 6 crossing of Stannard Brook is a 59-ft-long (bottom width), two-lane \npipe arch culvert consisting of one 22-foot corrugated plate pipe arch span (Vermont \nAgency of Transportation, written communication, March 28, 1995). The opening length of \nthe structure parallel to the bridge face is 21.9 ft.The pipe arch is supported by vertical, \nconcrete kneewalls. The channel is skewed approximately 10 degrees to the opening while \nthe opening-skew-to-roadway is zero degrees.
\nA scour hole 1.5 ft deeper than the mean thalweg depth was observed along the upstream \nend of the right kneewall during the Level I assessment. There was also a scour hole 0.5 ft \ndeeper than the mean thalweg depth observed along the downstream end of the left \nkneewall. The scour counter measures at the site included type-3 stone fill (less than 48 \ninches diameter) at the upstream and downstream end of the left and right kneewall. There \nwas also type-2 stone fill (less than 36 inches diameter) along the upstream right bank. \nAdditional details describing conditions at the site are included in the Level II Summary \nand Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge is determined and analyzed as another potential worst-case scour scenario. Total \nscour at a highway crossing is comprised of three components: 1) long-term streambed \ndegradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow \narea at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nkneewalls). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.
\nContraction scour for all modelled flows ranged from 0.0 to 2.3 ft. The worst-case \ncontraction scour occurred at the incipient roadway-overtopping discharge, which was \ngreater than the 100-year discharge. Left kneewall scour ranged from 11.7 to 16.8 ft. The \nworst-case left kneewall scour occurred at the 500-year discharge. Right kneewall scour \nranged from 13.7 to 16.7 ft. The worst-case right kneewall scour occurred at the incipient \nroadway-overtopping discharge. Additional information on scour depths and depths to \narmoring are included in the section titled “Scour Results”. Scoured-streambed elevations, \nbased on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the \nscour computed at the bridge is presented in figure 8. Scour depths were calculated \nassuming an infinite depth of erosive material and a homogeneous particle-size distribution. \nDuring the Level I survey ledge was discovered at the upstream end of the right abutment. \nThe ledge in the channel may limit scour depths.
\nIt is generally accepted that the Froehlich equation (abutment/ kneewall scour) gives \n“excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). \nUsually, computed scour depths are evaluated in combination with other information \nincluding (but not limited to) historical performance during flood events, the geomorphic \nstability assessment, existing scour protection measures, and the results of the hydraulic \nanalyses. Therefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97674","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., and Hammond, R.E., 1997, Level II scour analysis for Bridge 23 (WALDTH00060023) on Town Highway 6, crossing Stannard Brook, Walden, Vermont: U.S. Geological Survey Open-File Report 97-674, 50 p., https://doi.org/10.3133/ofr97674.","productDescription":"50 p.","costCenters":[],"links":[{"id":176250,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97674.GIF"},{"id":279689,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0674/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Walden","otherGeospatial":"Stannard Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.375,44.5 ], [ -72.375,44.625 ], [ -72.125,44.625 ], [ -72.125,44.5 ], [ -72.375,44.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a80c8","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240592,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hammond, Robert E.","contributorId":61862,"corporation":false,"usgs":true,"family":"Hammond","given":"Robert","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":240593,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49991,"text":"ofr97751 - 1997 - Level II scour analysis for Bridge 16 (RIPTTH00110016) on Town Highway 11, crossing the Middle Branch Middlebury River, Ripton, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T13:44:59","indexId":"ofr97751","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-751","title":"Level II scour analysis for Bridge 16 (RIPTTH00110016) on Town Highway 11, crossing the Middle Branch Middlebury River, Ripton, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nRIPTTH00110016 on Town Highway 11 crossing the Middle Branch Middlebury River, \nRipton, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, \nincluding a quantitative analysis of stream stability and scour (U.S. Department of \nTransportation, 1993). Results of a Level I scour investigation also are included in \nAppendix E of this report. A Level I investigation provides a qualitative geomorphic \ncharacterization of the study site. Information on the bridge, gleaned from Vermont Agency \nof Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II \nanalyses and is found in Appendix D.
\nThe site is in the Green Mountain section of the New England physiographic province in \nwest-central Vermont. The 6.6-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover consists of shrubs, brush and trees \nexcept for the upstream left bank which is completely forested.
\nIn the study area, the Middle Branch Middlebury River has an incised, sinuous channel with \na slope of approximately 0.03 ft/ft, an average channel top width of 68 ft and an average \nbank height of 5 ft. The channel bed material ranges from gravel to boulder with a median \ngrain size (D50) of 97.6 mm (0.320 ft). The geomorphic assessment at the time of the Level \nI and Level II site visit on June 11, 1996, indicated that the reach was stable.
\nThe Town Highway 11 crossing of the Middle Branch Middlebury River is a 44-ft-long, \ntwo-lane bridge consisting of one 42-foot steel-beam span (Vermont Agency of \nTransportation, written communication, December 15, 1995). The opening length of the \nstructure parallel to the bridge face is 40.2 ft. The bridge is supported by vertical, concrete \nabutments with wingwalls. The channel is skewed approximately 40 degrees to the opening. \nThe opening-skew-to-roadway value from the VTAOT database is 20 degrees while 30 \ndegrees was computed from surveyed points.
\nA scour hole, 3 ft deeper than the mean thalweg depth, was observed along the left \nabutment and upstream left wingwall during the Level I assessment. In addition, 1 ft of \nchannel scour was observed just downstream of the downstream left wingwall along the left \nbank. Scour countermeasures at the site included type-2 stone fill (less than 36 inches \ndiameter) along the upstream left and right banks and along the upstream end of the \ndownstream left wingwall. Additional details describing conditions at the site are included \nin the Level II Summary and Appendices D \nand E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. Total scour at a highway crossing is comprised of \nthree components: 1) long-term streambed degradation; 2) contraction scour (due to \naccelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused \nby accelerated flow around piers and abutments). Total scour is the sum of the three \ncomponents. Equations are available to compute depths for contraction and local scour and \na summary of the results of these computations follows.
\nContraction scour for all modelled flows ranged from 0.1 to 0.4 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 7.2 to \n8.6 ft along the right abutment and from 11.7 to 13.7 ft along the left abutment. The worstcase abutment scour occurred at the 500-year discharge. Additional information on scour \ndepths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. \nA cross-section of the scour computed at the bridge is presented in figure 8. Scour depths \nwere calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97751","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Burns, R.L., 1997, Level II scour analysis for Bridge 16 (RIPTTH00110016) on Town Highway 11, crossing the Middle Branch Middlebury River, Ripton, Vermont: U.S. Geological Survey Open-File Report 97-751, iv, 48 p., https://doi.org/10.3133/ofr97751.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":176252,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97751.GIF"},{"id":279687,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0751/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Ripton","otherGeospatial":"Middlebury River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8286","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240596,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":49992,"text":"ofr97752 - 1997 - Level II scour analysis for Bridge 17 (LYNDTH00020017) on Town Highway 2, crossing Hawkins Brook, Lyndon, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T15:34:25","indexId":"ofr97752","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-752","title":"Level II scour analysis for Bridge 17 (LYNDTH00020017) on Town Highway 2, crossing Hawkins Brook, Lyndon, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure LYNDTH00020017 on Town Highway 2 crossing Hawkins Brook, Lyndon, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.
The site is in the Green Mountain section of the New England physiographic province in northeastern Vermont. The 7.7-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest on the left and right upstream overbanks. The downstream left and right overbanks are brushland.
In the study area, Hawkins Brook has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 78 ft and an average bank height of 7.3 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) of 46.6 mm (0.153 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 4, 1995, indicated that the reach was laterally unstable with the presence of point bars and side bars.
The Town Highway 2 crossing of Hawkins Brook is a 49-ft-long, two-lane bridge consisting of a 46-foot steel-stringer span (Vermont Agency of Transportation, written communication, March 27, 1995). The opening length of the structure parallel to the bridge face is 43 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 45 degrees to the opening while the computed opening-skew-to-roadway is zero degrees.
A scour hole 0.75 ft deeper than the mean thalweg depth was observed along the downstream left abutment during the Level I assessment. The only scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) at the upstream end of the downstream left wingwall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.
Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for all modelled flows ranged from 0.1 to 0.9 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 3.8 to 6.6 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.
It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97752","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., and Medalie, L., 1997, Level II scour analysis for Bridge 17 (LYNDTH00020017) on Town Highway 2, crossing Hawkins Brook, Lyndon, Vermont: U.S. Geological Survey Open-File Report 97-752, iv, 48 p., https://doi.org/10.3133/ofr97752.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":176839,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97752.GIF"},{"id":279686,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0752/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Lyndon","otherGeospatial":"Hawkins Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8265","contributors":{"authors":[{"text":"Wild, Emily C. 0000-0001-6157-7629 ecwild@usgs.gov","orcid":"https://orcid.org/0000-0001-6157-7629","contributorId":1810,"corporation":false,"usgs":true,"family":"Wild","given":"Emily","email":"ecwild@usgs.gov","middleInitial":"C.","affiliations":[{"id":5081,"text":"Libraries","active":false,"usgs":true}],"preferred":false,"id":240597,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Medalie, Laura 0000-0002-2440-2149 lmedalie@usgs.gov","orcid":"https://orcid.org/0000-0002-2440-2149","contributorId":3657,"corporation":false,"usgs":true,"family":"Medalie","given":"Laura","email":"lmedalie@usgs.gov","affiliations":[{"id":466,"text":"New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240598,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49995,"text":"ofr97755 - 1997 - Level II scour analysis for Bridge 6 (FAYSTH00010006) on Town Highway 1, crossing Shepard Brook, Fayston, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T13:12:18","indexId":"ofr97755","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-755","title":"Level II scour analysis for Bridge 6 (FAYSTH00010006) on Town Highway 1, crossing Shepard Brook, Fayston, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nFAYSTH00010006 on Town Highway 1 crossing Shepard Brook, \nFayston, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, \nincluding a quantitative analysis of stream stability and scour (U.S. Department of \nTransportation, 1993). Results of a Level I scour investigation also are included in \nAppendix E of this report. A Level I investigation provides a qualitative geomorphic \ncharacterization of the study site. Information on the bridge, gleaned from Vermont Agency \nof Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II \nanalyses and is found in Appendix D.
\nThe site is in the Green Mountain section of the New England physiographic province in \ncentral Vermont. The 16.6-mi2\n drainage area is in a predominantly rural and forested basin. \nIn the vicinity of the study site, the surface cover is forest.
\nIn the study area, Shepard Brook has an incised, sinuous channel with a slope of \napproximately 0.01 ft/ft, an average channel top width of 56 ft and an average bank height \nof 3 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) \nof 72.6 mm (0.238 ft). The geomorphic assessment at the time of the Level I and Level II \nsite visit on July 2, 1996, indicated that the reach was stable.
\nThe Town Highway 1 crossing of the Shepard Brook is a 42-ft-long, two-lane bridge \nconsisting of one 40-foot concrete T-beam span (Vermont Agency of Transportation, \nwritten communication, October 13, 1995). The opening length of the structure parallel to \nthe bridge face is 39.6 ft. The bridge is supported by vertical, concrete abutments with \nwingwalls. The channel is skewed approximately 15 degrees to the opening while the \ncalculated opening-skew-to-roadway is 30 degrees.
\nScour, 2.0 ft deeper than the mean thalweg depth, was observed along the right abutment \nduring the Level I assessment. The left abutment is undermined along the base of the \nfooting. In addition, 1.5 ft of scour was observed along the left abutment during the Level I \nassessment. The only scour protection measure at the site was type-1 stone fill (less than 12 \ninches diameter) along the left bank upstream and type-2 stone fill (less than 36 inches \ndiameter) along the upstream end of the upstream right wingwall. Additional details \ndescribing conditions at the site are included in the Level II Summary and Appendices D \nand E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge is determined and analyzed as another potential worst-case scour scenario. Total \nscour at a highway crossing is comprised of three components: 1) long-term streambed \ndegradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow \narea at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.
\nContraction scour for all modelled flows ranged from 0.9 to 3.9 ft. The worst-case \ncontraction scour occurred at the 500-year. Abutment scour ranged from 11.1 to 17.2 ft. The \nworst-case abutment scour occurred at the 500-year discharge. Additional information on \nscour depths and depths to armoring are included in the section titled “Scour Results”. \nScoured-streambed elevations, based on the calculated scour depths, are presented in tables \n1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour \ndepths were calculated assuming an infinite depth of erosive material and a homogeneous \nparticle-size distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97755","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Striker, L.K., and Flynn, R.H., 1997, Level II scour analysis for Bridge 6 (FAYSTH00010006) on Town Highway 1, crossing Shepard Brook, Fayston, Vermont: U.S. Geological Survey Open-File Report 97-755, iv, 51 p., https://doi.org/10.3133/ofr97755.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176842,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97755.GIF"},{"id":279683,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0755/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Fayston","otherGeospatial":"Shepard Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.875,44.125 ], [ -72.875,44.25 ], [ -72.75,44.25 ], [ -72.75,44.125 ], [ -72.875,44.125 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b16e4b07f02db6a596b","contributors":{"authors":[{"text":"Striker, Lora K.","contributorId":41481,"corporation":false,"usgs":true,"family":"Striker","given":"Lora","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":240604,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Flynn, Robert H. rflynn@usgs.gov","contributorId":2137,"corporation":false,"usgs":true,"family":"Flynn","given":"Robert","email":"rflynn@usgs.gov","middleInitial":"H.","affiliations":[{"id":405,"text":"NH/VT office of New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240603,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49997,"text":"ofr97758 - 1997 - Level II scour analysis for Bridge 16 (BURKTH00070016) on Town Highway 7, crossing Dish Mill Brook, Burke, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T12:58:04","indexId":"ofr97758","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-758","title":"Level II scour analysis for Bridge 16 (BURKTH00070016) on Town Highway 7, crossing Dish Mill Brook, Burke, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nBURKTH00070016 on Town Highway 7 crossing Dish Mill Brook, Burke, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.
\nThe site is in the White Mountain section of the New England physiographic province in \nnortheastern Vermont. The 6.0-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is forest except on the left bank \nupstream which is brushland.
\nIn the study area, Dish Mill Brook has an incised, sinuous channel with a slope of \napproximately 0.04 ft/ft, an average channel top width of 40 ft and an average bank height \nof 6 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) \nof 94.1 mm (0.309 ft). The geomorphic assessment at the time of the Level I and Level II \nsite visit on August 7, 1995, indicated that the reach was stable.
\nThe Town Highway 7 crossing of Dish Mill Brook is a 28-ft-long, two-lane bridge \nconsisting of one 24-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, March 24, 1995). The opening length of the structure parallel to the bridge \nface is 24.8 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The \nchannel is skewed approximately 35 degrees to the opening while the computed opening-skew-to-roadway is 35 degrees.
\nA scour hole 1.0 ft deeper than the mean thalweg depth was observed along the left and \nright abutments during the Level I assessment. In front of the upstream and downstream left \nwingwalls the scour depth was only 0.5 ft, while in front of the downstream right wingwall \nit was 0.75 ft and in front of the upstream right wingwall it was 0.3 ft. The scour \ncountermeasures at the site include type-1 stone fill (less than 12 inches diameter) at the \ndownstream end of the right abutment and along the downstream right wingwall. Type-2 \nstone fill (less than 36 inches diameter) is along the upstream left bank, the upstream and \ndownstream left wingwalls, and at the upstream end of the upstream right wingwall. \nAdditional details describing conditions at the site are included in the Level II Summary \nand Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge is determined and analyzed as another potential worst-case scour scenario. Total \nscour at a highway crossing is comprised of three components: 1) long-term streambed \ndegradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow \narea at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.
\nContraction scour for all modelled flows ranged from 0.0 to 0.5 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 6.7 to \n9.3 ft. The worst-case abutment scour occurred at the 500-year discharge for the left \nabutment and at the incipient road-overtopping discharge for the right abutment. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97758","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Burns, R.L., and Severance, T., 1997, Level II scour analysis for Bridge 16 (BURKTH00070016) on Town Highway 7, crossing Dish Mill Brook, Burke, Vermont: U.S. Geological Survey Open-File Report 97-758, iv, 51 p., https://doi.org/10.3133/ofr97758.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176338,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97758.GIF"},{"id":279681,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0758/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Burke","otherGeospatial":"Dish Mill Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a826b","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240607,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Severance, Tim","contributorId":53851,"corporation":false,"usgs":true,"family":"Severance","given":"Tim","affiliations":[],"preferred":false,"id":240606,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49998,"text":"ofr97759 - 1997 - Level II scour analysis for Bridge 3 (EASTTH00010003) on Town Highway 1, crossing the East Branch Passumpsic River, East Haven, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T12:40:17","indexId":"ofr97759","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-759","title":"Level II scour analysis for Bridge 3 (EASTTH00010003) on Town Highway 1, crossing the East Branch Passumpsic River, East Haven, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nEASTTH00010003 on Town Highway 1 crossing the East Branch Passumpsic River, East \nHaven, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, \nincluding a quantitative analysis of stream stability and scour (U.S. Department of \nTransportation, 1993). Results of a Level I scour investigation also are included in \nAppendix E of this report. A Level I investigation provides a qualitative geomorphic \ncharacterization of the study site. Information on the bridge, gleaned from Vermont Agency \nof Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II \nanalyses and is found in Appendix D.
\nThe site is in the White Mountain section of the New England physiographic province in \nnortheastern Vermont. The 50.4-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover on the left bank upstream is forest. \nOn the remaining three banks the surface cover is pasture while the immediate banks have \ndense woody vegetation.
\nIn the study area, the East Branch Passumpsic River has an incised, sinuous channel with a \nslope of approximately 0.003 ft/ft, an average channel top width of 62 ft and an average \nbank height of 5 ft. The channel bed material ranges from gravel to boulder with a median \ngrain size (D50) of 61.5 mm (0.187 ft). The geomorphic assessment at the time of the Level \nI and Level II site visit on August 14, 1995, indicated that the reach was stable.
\nThe Town Highway 1 crossing of the East Branch Passumpsic River is a 89-ft-long, two-lane bridge consisting of one 87-foot steel-beam span (Vermont Agency of Transportation, \nwritten communication, March 17, 1995). The opening length of the structure parallel to the \nbridge face is 84.7 ft. The bridge is supported by vertical, concrete abutments with sloped \nstone fill in front that creates a spill through embankment. The channel is skewed \napproximately zero degrees to the opening and the opening-skew-to-roadway is also zero \ndegrees.
\nChannel scour 0.5 ft deeper than the mean thalweg depth was observed to the left of the \ncenter of the channel under the bridge during the Level I assessment. The scour \ncountermeasures at the site are type-2 stone fill (less than 36 inches diameter) along the \ndownstream left bank and type-4 stone fill (less than 60 inches diameter) in front of the \nabutments creating spill through slopes. Additional details describing conditions at the site \nare included in the Level II Summary and Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. Total scour at a highway crossing is comprised of \nthree components: 1) long-term streambed degradation; 2) contraction scour (due to \naccelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused \nby accelerated flow around piers and abutments). Total scour is the sum of the three \ncomponents. Equations are available to compute depths for contraction and local scour and \na summary of the results of these computations follows.
\nContraction scour for all modelled flows ranged from 0 to 1.8 ft. The worst-case contraction \nscour occurred at the 500-year discharge. Abutment scour ranged from 6.4 to 11.7 ft. The \nworst-case abutment scour occurred at the 500-year discharge. Additional information on \nscour depths and depths to armoring are included in the section titled “Scour Results”. \nScoured-streambed elevations, based on the calculated scour depths, are presented in tables \n1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour \ndepths were calculated assuming an infinite depth of erosive material and a homogeneous \nparticle-size distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97759","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Burns, R.L., and Boehmler, E.M., 1997, Level II scour analysis for Bridge 3 (EASTTH00010003) on Town Highway 1, crossing the East Branch Passumpsic River, East Haven, Vermont: U.S. Geological Survey Open-File Report 97-759, iv, 48 p., https://doi.org/10.3133/ofr97759.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":176339,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97759.GIF"},{"id":279680,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0759/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"East Haven","otherGeospatial":"Passumpsic River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b19e4b07f02db6a7eca","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240608,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240609,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49999,"text":"ofr97760 - 1997 - Level II scour analysis for Bridge 4 (MAIDTH00070004) on Town Highway 7, crossing Cutler Mill Brook, Maidstone, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T12:28:59","indexId":"ofr97760","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-760","title":"Level II scour analysis for Bridge 4 (MAIDTH00070004) on Town Highway 7, crossing Cutler Mill Brook, Maidstone, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nMAIDTH00070004 on Town Highway 7 crossing the Cutler Mill Brook, Maidstone, \nVermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including \na quantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.
\nThe site is in the White Mountain section of the New England physiographic province in \nnortheastern Vermont. The 18.1-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is predominantly shrub and \nbrushland.
\nIn the study area, the Cutler Mill Brook has a non-incised, meandering channel with local \nbraiding and a slope of approximately 0.004 ft/ft, an average channel top width of 43 ft and \nan average bank height of 2 ft. The channel bed material ranges from sand to cobble with a \nmedian grain size (D50) of 27.6 mm (0.091 ft). The geomorphic assessment at the time of \nthe Level I and Level II site visit on July 19, 1995, indicated that the reach was laterally \nunstable due to large meanders in the channel.
\nThe Town Highway 7 crossing of the Cutler Mill Brook is a 25-ft-long, one-lane bridge \nconsisting of one 22-foot concrete span (Vermont Agency of Transportation, written \ncommunication, August 5, 1994). The opening length of the structure parallel to the bridge \nface is 21.7 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The \nchannel is skewed approximately 20 degrees to the opening while the opening-skew-to-roadway is 0 degrees.
\nA scour hole 2.0 ft deeper than the mean thalweg depth was observed along the left \nabutment during the Level I assessment. The only scour protection measure at the site was \ntype-2 stone fill (less than 36 inches diameter) along both banks upstream, along the entire \nbase length of the upstream left wingwall, and along the upstream end of the upstream right \nwingwall. Additional details describing conditions at the site are included in the Level II \nSummary and Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge was determined and analyzed as another potential worst-case scour scenario. \nTotal scour at a highway crossing is comprised of three components: 1) long-term \nstreambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction \nin flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.
\nContraction scour for all modelled flows ranged from 2.2 to 4.2 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 5.7 to \n12.4 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97760","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Striker, L.K., and Medalie, L., 1997, Level II scour analysis for Bridge 4 (MAIDTH00070004) on Town Highway 7, crossing Cutler Mill Brook, Maidstone, Vermont: U.S. Geological Survey Open-File Report 97-760, iv, 51 p., https://doi.org/10.3133/ofr97760.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176340,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97760.GIF"},{"id":279679,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0760/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Maidstone","otherGeospatial":"Cutler Mill Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -71.625,44.5 ], [ -71.625,44.625 ], [ -71.5,44.625 ], [ -71.5,44.5 ], [ -71.625,44.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a61ed","contributors":{"authors":[{"text":"Striker, Lora K.","contributorId":41481,"corporation":false,"usgs":true,"family":"Striker","given":"Lora","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":240611,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Medalie, Laura 0000-0002-2440-2149 lmedalie@usgs.gov","orcid":"https://orcid.org/0000-0002-2440-2149","contributorId":3657,"corporation":false,"usgs":true,"family":"Medalie","given":"Laura","email":"lmedalie@usgs.gov","affiliations":[{"id":466,"text":"New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240610,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50000,"text":"ofr97765 - 1997 - Level II scour analysis for Bridge 4 (RYEGTH00050004) on Town Highway 5, crossing the Wells River, Ryegate, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T16:18:31","indexId":"ofr97765","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-765","title":"Level II scour analysis for Bridge 4 (RYEGTH00050004) on Town Highway 5, crossing the Wells River, Ryegate, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nRYEGTH00050004 on Town Highway 5 crossing the Wells River, Ryegate, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.\nThe site is in the New England Upland section of the New England physiographic province \nin eastern Vermont. The 84.7-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover includes shrubs and brush on the \nupstream left bank and downstream right bank of the bridge. The upstream right bank and \ndownstream left bank of the bridge is forested.\nIn the study area, the Wells River has an incised, sinuous channel with a slope of \napproximately 0.008 ft/ft, an average channel top width of 107 ft and an average bank \nheight of 11 ft. The channel bed material ranges from gravel to boulder with a median grain \nsize (D50) of 67.4 mm (0.221 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on August 21, 1995, indicated that the reach was laterally unstable with \nmass wasting along the upstream right bank.\nThe Town Highway 5 crossing of the Wells River is a 108-ft-long, two-lane bridge \nconsisting of a 100-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, March 27, 1995). The opening length of the structure parallel to the bridge \nface is 93.4 ft. The bridge is supported by vertical, stone block abutments with wingwalls. \nThe channel is skewed approximately 50 degrees to the opening while the opening-skew-toroadway is 45 degrees. \nThe scour protection counter-measures at the site included type-1 stone fill (less than 12 \ninches diameter) along the downstream left road embankment. Also, type-2 stone fill (less \nthan 36 inches diameter) along the upstream right wingwall, extending 30 feet upstream \nalong the right bank, along the downstream end of the downstream right wingwall, along \nthe downstream right road embankment, and along the downstream left bank below the old \nrailroad bed. Additional details describing conditions at the site are included in the Level II \nSummary and Appendices D and E.\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. Total scour at a highway crossing is comprised of \nthree components: 1) long-term streambed degradation; 2) contraction scour (due to \naccelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused \nby accelerated flow around piers and abutments). Total scour is the sum of the three \ncomponents. Equations are available to compute depths for contraction and local scour and \na summary of the results of these computations follows.\nContraction scour for all modelled flows ranged from 1.8 to 2.6 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 10.2 to \n22.6 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution. \nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97765","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., and Hammond, R.E., 1997, Level II scour analysis for Bridge 4 (RYEGTH00050004) on Town Highway 5, crossing the Wells River, Ryegate, Vermont: U.S. Geological Survey Open-File Report 97-765, iv, 48 p., https://doi.org/10.3133/ofr97765.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":176341,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97765.PNG"},{"id":279678,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0765/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Ryegate","otherGeospatial":"Wells River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.25,44.125 ], [ -72.25,44.25 ], [ -72.125,44.25 ], [ -72.125,44.125 ], [ -72.25,44.125 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a6209","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240612,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hammond, Robert E.","contributorId":61862,"corporation":false,"usgs":true,"family":"Hammond","given":"Robert","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":240613,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50001,"text":"ofr97766 - 1997 - Level II scour analysis for Bridge 46 (BRNETH00610046) on Town Highway 61, crossing East Peacham Brook, Barnet, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T16:11:32","indexId":"ofr97766","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-766","title":"Level II scour analysis for Bridge 46 (BRNETH00610046) on Town Highway 61, crossing East Peacham Brook, Barnet, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nBRNETH00610046 on Town Highway 61 crossing East Peacham Brook, Barnet, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.\nThe site is in the New England Upland section of the New England physiographic province \nin east-central Vermont. The 15.8-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is forest.\nIn the study area, East Peacham Brook has an incised, sinuous channel with a slope of \napproximately 0.02 ft/ft, an average channel top width of 59 ft and an average bank height \nof 5 ft. The channel bed material ranges from gravel to boulder with a median grain size \n(D50) of 121 mm (0.397 ft). The geomorphic assessment at the time of the Level I and Level \nII site visit on August 23, 1995, indicated that the reach was laterally unstable with cut \nbanks both upstream and downstream of the bridge.\nThe Town Highway 61 crossing of East Peacham Brook is a 28-ft-long, one-lane bridge \nconsisting of one 26-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, March 24, 1995). The opening length of the structure parallel to the bridge \nface is 24.5 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The \nchannel is skewed approximately 5 degrees to the opening while the opening-skew-toroadway is zero degrees. \nA scour hole 0.7 ft deeper than the mean thalweg depth was observed along the upstream \nleft wingwall extending along the left abutment during the Level I assessment. The only \nscour protection measure at the site was type-2 stone fill (less than 36 inches diameter) at \nthe upstream end of the upstream left wingwall extending along the upstream left bank and \nalong the entire base of the downstream left wingwall. Additional details describing \nconditions at the site are included in the Level II Summary and Appendices D and E.\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge is determined and analyzed as another potential worst-case scour scenario. Total \nscour at a highway crossing is comprised of three components: 1) long-term streambed \ndegradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow \narea at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.\nContraction scour for all modelled flows ranged from 0 to 1.2 ft. The worst-case contraction \nscour occurred at the 500-year discharge. Abutment scour ranged from 10.4 to 13.9 ft. The \nworst-case abutment scour occurred at the 500-year discharge. Additional information on \nscour depths and depths to armoring are included in the section titled “Scour Results”. \nScoured-streambed elevations, based on the calculated scour depths, are presented in tables \n1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour \ndepths were calculated assuming an infinite depth of erosive material and a homogeneous \nparticle-size distribution. \nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97766","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., 1997, Level II scour analysis for Bridge 46 (BRNETH00610046) on Town Highway 61, crossing East Peacham Brook, Barnet, Vermont: U.S. Geological Survey Open-File Report 97-766, iv, 51 p., https://doi.org/10.3133/ofr97766.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176342,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97766.PNG"},{"id":279677,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0766/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Barnet","otherGeospatial":"East Peacham Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.25,44.25 ], [ -72.25,44.375 ], [ -72.0,44.375 ], [ -72.0,44.25 ], [ -72.25,44.25 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a60f8","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240614,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":50003,"text":"ofr97768 - 1997 - Level II scour analysis for Bridge 22 (WALDTH00180022) on Town Highway 18, crossing Coles Brook, Walden, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T16:01:28","indexId":"ofr97768","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-768","title":"Level II scour analysis for Bridge 22 (WALDTH00180022) on Town Highway 18, crossing Coles Brook, Walden, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nWALDTH00180022 on Town Highway 18 crossing Coles Brook also known as Joes \nBrook, Walden, Vermont (figures 1–8). A Level II study is a basic engineering analysis of \nthe site, including a quantitative analysis of stream stability and scour (U.S. Department of \nTransportation, 1993). Results of a Level I scour investigation also are included in \nAppendix E of this report. A Level I investigation provides a qualitative geomorphic \ncharacterization of the study site. Information on the bridge, gleaned from Vermont Agency \nof Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II \nanalyses and is found in Appendix D.\nThe site is in the New England Upland section of the New England physiographic province \nin northeastern Vermont. The 12.5-mi2\n drainage area is in a predominantly rural and \nforested basin. In the vicinity of the study site, the surface cover is predominantly forested \nwhile the downstream left bank is shrub and brushland.\nIn the study area, the Coles Brook has an incised, sinuous channel with a slope of \napproximately 0.004 ft/ft, an average channel top width of 54 ft and an average bank height \nof 4 ft. The channel bed material ranges from gravel to bedrock with a median grain size \n(D50) of 124.1 mm (0.407 ft). The D50 was taken from a pebble count in the downstream \nchannel, because the upstream channel is primarily bedrock. The geomorphic assessment at \nthe time of the Level I and Level II site visit on August 8, 1995, indicated that the reach was \nstable.\nThe Town Highway 18 crossing of the Coles Brook is a 46-ft-long, one-lane bridge \nconsisting of one 44-foot steel-beam span with a wooden deck (Vermont Agency of \nTransportation, written communication, April 5, 1995). The opening length of the structure \nparallel to the bridge face is 41.4 ft. The bridge is supported by a vertical, concrete abutment \nwith wingwalls on the left and by a vertical, stone abutment with stone wingwalls with a \nconcrete cap on the right. The channel is skewed approximately 5 degrees to the opening \nwhile the computed opening-skew-to-roadway is 10 degrees. \nThe only scour protection measure at the site was a stone wall along the upstream left bank \nand type-2 stone fill (less than 36 inches diameter) along the entire base length of the \nupstream left wingwall, left abutment, and downstream left wing wall. Additional details \ndescribing conditions at the site are included in the Level II Summary and Appendices D \nand E.\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100-year and 500-year discharges. Total scour at a highway crossing is comprised of \nthree components: 1) long-term streambed degradation; 2) contraction scour (due to \naccelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused \nby accelerated flow around piers and abutments). Total scour is the sum of the three \ncomponents. Equations are available to compute depths for contraction and local scour and \na summary of the results of these computations follows.\nContraction scour for all modelled flows was 0.0 ft. Abutment scour ranged from 6.4 to 7.9 \nft at the left abutment and from 11.8 to 14.9 ft at the right abutment. The worst-case \nabutment scour occurred at the 500-year discharge. Additional information on scour depths \nand depths to armoring are included in the section titled “Scour Results”. Scouredstreambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. \nA cross-section of the scour computed at the bridge is presented in figure 8. Scour depths \nwere calculated assuming an infinite depth of erosive material and a homogeneous particlesize distribution. \nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97768","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Striker, L.K., and Ivanoff, M.A., 1997, Level II scour analysis for Bridge 22 (WALDTH00180022) on Town Highway 18, crossing Coles Brook, Walden, Vermont: U.S. Geological Survey Open-File Report 97-768, iv, 48 p., https://doi.org/10.3133/ofr97768.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":176344,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97768.PNG"},{"id":279675,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0768/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Walden","otherGeospatial":"Coles Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.25,44.375 ], [ -72.25,44.5 ], [ -72.0,44.5 ], [ -72.0,44.375 ], [ -72.25,44.375 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a810d","contributors":{"authors":[{"text":"Striker, Lora K.","contributorId":41481,"corporation":false,"usgs":true,"family":"Striker","given":"Lora","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":240617,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240616,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50005,"text":"ofr97770 - 1997 - Level II scour analysis for Bridge 8 (WELLTH00020008) on Town Highway 2, crossing Wells Brook, Wells, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T15:28:52","indexId":"ofr97770","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-770","title":"Level II scour analysis for Bridge 8 (WELLTH00020008) on Town Highway 2, crossing Wells Brook, Wells, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nWELLTH00020008 on Town Highway 2 crossing the Wells Brook, Wells, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.\nThe site is in the Taconic section of the New England physiographic province in southwestern Vermont. The 14.4-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover on the right overbanks is \npredominantly suburban while the immediate banks are vegetated with trees and brush. The \nleft bank upstream and downstream is predominantly pasture.\nIn the study area, the Wells Brook has an incised, straight channel with a slope of \napproximately 0.005 ft/ft, an average channel top width of 51 ft and an average bank height \nof 7 ft. The channel bed material ranges from gravel to boulder with a median grain size \n(D50) of 48.6 mm (0.159 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on September 19, 1995, indicated that the reach was stable.\nThe Town Highway 2 crossing of the Wells Brook is a 35-ft-long, two-lane bridge \nconsisting of one 32-foot concrete span (Vermont Agency of Transportation, written \ncommunication, March 22, 1995). The opening length of the structure parallel to the bridge \nface is 31.7 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The \nchannel is skewed approximately 10 degrees to the opening while the opening-skew-toroadway is 5 degrees. \nA scour hole 1.5 ft deeper than the mean thalweg depth was observed along the left \nabutment during the Level I assessment. The only scour protection measure at the site was \ntype-2 stone fill (less than 36 inches diameter) along the left bank upstream, and type-5 \n(placed stone wall) at the upstream end of the upstream left wingwall, at the downstream \nend of the downstream left wingwall, and along the downstream left bank. Additional \ndetails describing conditions at the site are included in the Level II Summary and \nAppendices D and E.\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge is determined and analyzed as another potential worst-case scour scenario. Total \nscour at a highway crossing is comprised of three components: 1) long-term streambed \ndegradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow \narea at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.\nContraction scour for all modelled flows ranged from 0.0 to 0.8 ft. The worst-case \ncontraction scour occurred at the incipient roadway-overtopping discharge, which was less \nthan the 100-year discharge. Abutment scour ranged from 5.6 to 10.0 ft at the left abutment \nand from 3.1 to 4.2 ft at the right abutment. The worst-case abutment scour occurred at the \nincipient roadway-overtopping discharge at the left abutment. Additional information on \nscour depths and depths to armoring are included in the section titled “Scour Results”. \nScoured-streambed elevations, based on the calculated scour depths, are presented in tables \n1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour \ndepths were calculated assuming an infinite depth of erosive material and a homogeneous \nparticle-size distribution. \nUsually, computed scour depths are evaluated in combination with other information \nincluding (but not limited to) historical performance during flood events, the geomorphic \nstability assessment, existing scour protection measures, and the results of the hydraulic \nanalyses. Therefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97770","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Striker, L.K., and Ivanoff, M.A., 1997, Level II scour analysis for Bridge 8 (WELLTH00020008) on Town Highway 2, crossing Wells Brook, Wells, Vermont: U.S. Geological Survey Open-File Report 97-770, iv, 51 p., https://doi.org/10.3133/ofr97770.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176713,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97770.PNG"},{"id":279673,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0770/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Wells","otherGeospatial":"Wells Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -73.25,43.375 ], [ -73.25,43.5 ], [ -73.125,43.5 ], [ -73.125,43.375 ], [ -73.25,43.375 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b16e4b07f02db6a5639","contributors":{"authors":[{"text":"Striker, Lora K.","contributorId":41481,"corporation":false,"usgs":true,"family":"Striker","given":"Lora","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":240621,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240620,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50006,"text":"ofr97771 - 1997 - Level II scour analysis for Bridge 41 (ANDOVT00110041) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T12:32:19","indexId":"ofr97771","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-771","title":"Level II scour analysis for Bridge 41 (ANDOVT00110041) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure ANDOVT00110041 on State Route 11 crossing the Middle Branch Williams River, Andover, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.
The site is in the Green Mountain section of the New England physiographic province in southeastern Vermont. The 12.1-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is grass on the upstream right overbank while the immediate banks have dense woody vegetation. The upstream left overbank and downstream right overbank are brushland. The downstream left overbank is forested.
In the study area, the Middle Branch Williams River has an incised, sinuous channel with a slope of approximately 0.018 ft/ft, an average channel top width of 71 ft and an average bank height of 4 ft. The channel bed material ranges from gravel to boulders with a median grain size (D50) of 85.0 mm (0.279 ft). The geomorphic assessment at the time of the Level I and Level II site visit on September 10, 1996, indicated that the reach was laterally unstable due to a cut-bank present on the upstream right bank and a wide channel bar with vegetation in the upstream reach.
The State Route 11 crossing of the Middle Branch Williams River is a 46-ft-long, two-lane bridge consisting of a concrete 44-foot tee-beam span (Vermont Agency of Transportation, written communication, March 29, 1995). The opening length of the structure parallel to the bridge face is 42 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 35 degrees to the opening while the opening-skew-toroadway is zero degrees.
A scour hole 0.8 ft deeper than the mean thalweg depth was observed along the downstream end of the left abutment and downstream left wingwall during the Level I assessment. Type- 2 stone fill (less than 36 inches diameter) protects the upstream end of the upstream left wingwall, the downstream ends of the downstream left and right wingwalls and the downstream right road embankment. Type-3 stone fill protects the upstream end of the upstream right wingwall and the upstream right bank. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.
Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for all modelled flows ranged from 0.0 to 2.1 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 11.1 to 18.7 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.
It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97771","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., and Hammond, R.E., 1997, Level II scour analysis for Bridge 41 (ANDOVT00110041) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont: U.S. Geological Survey Open-File Report 97-771, iv, 52 p., https://doi.org/10.3133/ofr97771.","productDescription":"iv, 52 p.","numberOfPages":"57","costCenters":[],"links":[{"id":176714,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97771.PNG"},{"id":279672,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0771/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Andover","otherGeospatial":"Williams River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -73.125,44.375 ], [ -73.125,44.5 ], [ -73.0,44.5 ], [ -73.0,44.375 ], [ -73.125,44.375 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a61ab","contributors":{"authors":[{"text":"Wild, Emily C. 0000-0001-6157-7629 ecwild@usgs.gov","orcid":"https://orcid.org/0000-0001-6157-7629","contributorId":1810,"corporation":false,"usgs":true,"family":"Wild","given":"Emily","email":"ecwild@usgs.gov","middleInitial":"C.","affiliations":[{"id":5081,"text":"Libraries","active":false,"usgs":true}],"preferred":false,"id":240622,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hammond, Robert E.","contributorId":61862,"corporation":false,"usgs":true,"family":"Hammond","given":"Robert","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":240623,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50008,"text":"ofr97772 - 1997 - Level II scour analysis for Bridge 18 (SHEFTH00410018) on Town Highway 41, crossing Millers Run, Sheffield, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T14:15:28","indexId":"ofr97772","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-772","title":"Level II scour analysis for Bridge 18 (SHEFTH00410018) on Town Highway 41, crossing Millers Run, Sheffield, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure SHEFTH00410018 on Town Highway 41 crossing Millers Run, Sheffield, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.
The site is in the White Mountain section of the New England physiographic province in northeastern Vermont. The 16.2-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is grass upstream and downstream of the bridge while the immediate banks have dense woody vegetation.
In the study area, Millers Run has an incised, straight channel with a slope of approximately 0.01 ft/ft, an average channel top width of 50 ft and an average bank height of 6 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) of 50.9 mm (0.167 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 1, 1995, indicated that the reach was laterally unstable, which is evident in the moderate to severe fluvial erosion in the upstream reach.
The Town Highway 41 crossing of the Millers Run is a 30-ft-long, one-lane bridge consisting of a 28-foot steel-stringer span (Vermont Agency of Transportation, written communication, March 28, 1995). The opening length of the structure parallel to the bridge face is 22.2 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 20 degrees to the opening. The computed opening-skewto-roadway is 5 degrees, while it is zero degrees in the historical form.
A scour hole 1.0 ft deeper than the mean thalweg depth was observed along the left abutment during the Level I assessment. The scour protection measure at the site includes type-1 stone fill (less than 12 inches diameter) along the upstream right wingwall and the upstream left wingwall. Type-2 stone fill (less than 36 inches diameter) extends along the downstream end of the downstream left wingwall, the upstream right bank and the downstream left bank. The downstream right bank is protected by type-2 stone fill and a stone masonry wall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.
Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge is determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for all modelled flows ranged from 0.2 to 1.8 ft. The worst-case contraction scour occurred at the 100-year and 500-year discharges. Left abutment scour ranged from 14.1 to 16.4 ft. The worst-case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 6.9 to 9.3 ft. The worst-case right abutment scour occurred at the incipient roadway-overtopping discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.
It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97772","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., and Boehmler, E.M., 1997, Level II scour analysis for Bridge 18 (SHEFTH00410018) on Town Highway 41, crossing Millers Run, Sheffield, Vermont: U.S. Geological Survey Open-File Report 97-772, iv, 51 p., https://doi.org/10.3133/ofr97772.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176806,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97772.PNG"},{"id":279671,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0772/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Sheffield","otherGeospatial":"Millers Run","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a81cb","contributors":{"authors":[{"text":"Wild, Emily C. 0000-0001-6157-7629 ecwild@usgs.gov","orcid":"https://orcid.org/0000-0001-6157-7629","contributorId":1810,"corporation":false,"usgs":true,"family":"Wild","given":"Emily","email":"ecwild@usgs.gov","middleInitial":"C.","affiliations":[{"id":5081,"text":"Libraries","active":false,"usgs":true}],"preferred":false,"id":240625,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240626,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50009,"text":"ofr97773 - 1997 - Level II scour analysis for Bridge 38 (JERITH0020038) on Town Highway 20, crossing the Lee River, Jericho, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T14:51:05","indexId":"ofr97773","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-773","title":"Level II scour analysis for Bridge 38 (JERITH0020038) on Town Highway 20, crossing the Lee River, Jericho, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure JERITH00200038 on Town Highway 20 crossing the Lee River, Jericho, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, obtained from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.
The site is in the Green Mountain section of the New England physiographic province and the Champlain section of the St. Lawrence physiographic province in northwestern Vermont. The 12.9-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover on the upstream and downstream right overbank is pasture while the immediate banks have dense woody vegetation. The surface cover on the upstream and downstream left overbank is forested.
In the study area, the Lee River has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 89 ft and an average bank height of 14 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) of 45.9 mm (0.151 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 2, 1996, indicated that the reach was stable.
The Town Highway 20 crossing of the Lee River is a 49-ft-long, one-lane bridge consisting of a steel through truss span (Vermont Agency of Transportation, written communication, December 12, 1995). The opening length of the structure parallel to the bridge face is 44 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 10 degrees to the opening while the computed opening-skew-toroadway is 5 degrees.
A scour hole 1 ft deeper than the mean thalweg depth was observed in the center of the channel during the Level I assessment. Scour countermeasures at the site include type-1 stone fill (less than 12 inches diameter) at the downstream left road embankment. Type-2 stone fill (less than 36 inches diameter) protects the upstream left wingwall, the upstream and downstream right wingwalls and the upstream end of the right abutment. Type-3 stone fill (less than 48 inches diameter) protects the left abutment. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.
Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for all modelled flows was zero. Abutment scour ranged from 4.9 to 10.7 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.
It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97773","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., and Degnan, J.R., 1997, Level II scour analysis for Bridge 38 (JERITH0020038) on Town Highway 20, crossing the Lee River, Jericho, Vermont: U.S. Geological Survey Open-File Report 97-773, iv, 48 p., https://doi.org/10.3133/ofr97773.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":176807,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97773.PNG"},{"id":279670,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0773/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Jericho","otherGeospatial":"Lee River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a6271","contributors":{"authors":[{"text":"Wild, Emily C. 0000-0001-6157-7629 ecwild@usgs.gov","orcid":"https://orcid.org/0000-0001-6157-7629","contributorId":1810,"corporation":false,"usgs":true,"family":"Wild","given":"Emily","email":"ecwild@usgs.gov","middleInitial":"C.","affiliations":[{"id":5081,"text":"Libraries","active":false,"usgs":true}],"preferred":false,"id":240628,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Degnan, James R. 0000-0002-5665-9010 jrdegnan@usgs.gov","orcid":"https://orcid.org/0000-0002-5665-9010","contributorId":498,"corporation":false,"usgs":true,"family":"Degnan","given":"James","email":"jrdegnan@usgs.gov","middleInitial":"R.","affiliations":[{"id":466,"text":"New England Water Science Center","active":true,"usgs":true},{"id":405,"text":"NH/VT office of New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240627,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50010,"text":"ofr97774 - 1997 - Level II scour analysis for Bridge 29 (DORSTH00100029) on Town Highway 10, crossing the Mettawee River, Dorset, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T13:29:02","indexId":"ofr97774","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-774","title":"Level II scour analysis for Bridge 29 (DORSTH00100029) on Town Highway 10, crossing the Mettawee River, Dorset, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure DORSTH00100029 on Town Highway 10 crossing the Mettawee River, Dorset, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.
The site is in the Taconic section of the New England physiographic province in southwestern Vermont. The 9.5-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest on the upstream left overbank and the upstream and downstream right overbanks. The downstream left overbank is pasture and brushland.
In the study area, the Mettawee River has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 66 ft and an average bank height of 8 ft. The channel bed material ranges from gravel to boulders with a median grain size (D50) of 79.0 mm (0.259 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 5, 1996, indicated that the reach was stable.
The Town Highway 10 crossing of the Mettawee River is a 26-ft-long, two-lane bridge consisting of a 24-ft steel-stringer span (Vermont Agency of Transportation, written communication, September 28, 1995). The opening length of the structure parallel to the bridge face is 24.1 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 45 degrees to the opening while the opening-skew-to-roadway is zero degrees.
At the upstream end of the right abutment, there is a scour hole 1.0 ft deeper than the mean thalweg depth. Scour counter-measures at the site include type-1 stone fill (less than 12 inches diameter) along the downstream right wingwall. Type-2 stone fill (less than 36 inches diameter) is present along the downstream left and right banks. Type-3 stone fill (less than 48 inches diameter) is present along the upstream left bank and sparsely in front of the right abutment. A concrete wall (old abutment) extends along the upstream right bank. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.
Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge is determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for all modelled flows ranged from 0.4 to 1.9 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 10.5 to 10.8 ft. The worst-case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 11.4 to 11.9 ft. The worst-case right abutment scour occurred at the 100-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.
It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97774","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., 1997, Level II scour analysis for Bridge 29 (DORSTH00100029) on Town Highway 10, crossing the Mettawee River, Dorset, Vermont: U.S. Geological Survey Open-File Report 97-774, iv, 51 p., https://doi.org/10.3133/ofr97774.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176808,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97774.PNG"},{"id":279669,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0774/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Dorset","otherGeospatial":"Mettawee River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b19e4b07f02db6a7f30","contributors":{"authors":[{"text":"Wild, Emily C. 0000-0001-6157-7629 ecwild@usgs.gov","orcid":"https://orcid.org/0000-0001-6157-7629","contributorId":1810,"corporation":false,"usgs":true,"family":"Wild","given":"Emily","email":"ecwild@usgs.gov","middleInitial":"C.","affiliations":[{"id":5081,"text":"Libraries","active":false,"usgs":true}],"preferred":false,"id":240629,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":50011,"text":"ofr97775 - 1997 - Level II scour analysis for Bridge 39 (PEACTH00620039) on Town Highway 62, crossing South Peacham Brook, Peacham, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T14:50:57","indexId":"ofr97775","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-775","title":"Level II scour analysis for Bridge 39 (PEACTH00620039) on Town Highway 62, crossing South Peacham Brook, Peacham, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nPEACTH00620039 on Town Highway 62 crossing South Peacham Brook, Peacham, \nVermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including \na quantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.\nThe site is in the New England Upland section of the New England physiographic province \nin northeastern Vermont. The 9.1-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is forest on the left bank upstream \nand downstream of the bridge. The surface cover on the right bank upstream and \ndownstream is shrubs and brush.\nIn the study area, South Peacham Brook has an incised, straight channel with a slope of \napproximately 0.02 ft/ft, an average channel top width of 43 ft and an average bank height \nof 8 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) \nof 51.4 mm (0.168 ft). The geomorphic assessment at the time of the Level I and Level II \nsite visit on August 23, 1995, indicated that the reach was stable.\nThe Town Highway 62 crossing of South Peacham Brook is a 23-ft-long, one-lane bridge \nconsisting of one 22-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, March 27, 1995). The opening length of the structure parallel to the bridge \nface is 20.1 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The \nchannel is skewed approximately 15 degrees to the opening while the computed openingskew-to-roadway is 10 degrees. \nThe footing on the right abutment and the footing on the upstream left wingwall were \nexposed during the Level I assessment. The scour countermeasures at the site included type-\n2 stone fill (less than 36 inches diameter) along the upstream and downstream right \nwingwalls and at the upstream end of the upstream left wingwall and at the downstream end \nof the downstream left wingwall. Type-3 stone fill (less than 48 inches diameter) was along \nthe upstream left and right banks and the downstream right bank. On the downstream left \nbank, the scour countermeasure was a stone wall. Additional details describing conditions \nat the site are included in the Level II Summary and Appendices D and E.\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge is determined and analyzed as another potential worst-case scour scenario. Total \nscour at a highway crossing is comprised of three components: 1) long-term streambed \ndegradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow \narea at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.\nContraction scour for all modelled flows ranged from 1.0 to 1.6 ft. The worst-case \ncontraction scour occurred at the 100-year discharge. Abutment scour ranged from 5.9 to \n7.4 ft. The worst-case abutment scour occurred at the incipient roadway-overtopping \ndischarge, which is less than the 100-year discharge. Additional information on scour \ndepths and depths to armoring are included in the section titled “Scour Results”. Scouredstreambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. \nA cross-section of the scour computed at the bridge is presented in figure 8. Scour depths \nwere calculated assuming an infinite depth of erosive material and a homogeneous particlesize distribution. However, there is a bedrock outcrop across the channel just upstream of \nthe bridge.\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97775","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Burns, R.L., and Degnan, J.R., 1997, Level II scour analysis for Bridge 39 (PEACTH00620039) on Town Highway 62, crossing South Peacham Brook, Peacham, Vermont: U.S. Geological Survey Open-File Report 97-775, iv, 51 p., https://doi.org/10.3133/ofr97775.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176809,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97775.PNG"},{"id":279668,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0775/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Peacham","otherGeospatial":"Peacham Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a625b","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240631,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Degnan, James R. 0000-0002-5665-9010 jrdegnan@usgs.gov","orcid":"https://orcid.org/0000-0002-5665-9010","contributorId":498,"corporation":false,"usgs":true,"family":"Degnan","given":"James","email":"jrdegnan@usgs.gov","middleInitial":"R.","affiliations":[{"id":405,"text":"NH/VT office of New England Water Science Center","active":true,"usgs":true},{"id":466,"text":"New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240630,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50012,"text":"ofr97776 - 1997 - Level II scour analysis for Bridge 34 (CONCTH00110034) on Town Highway 11, crossing Miles Stream, Concord, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T14:45:22","indexId":"ofr97776","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-776","title":"Level II scour analysis for Bridge 34 (CONCTH00110034) on Town Highway 11, crossing Miles Stream, Concord, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nCONCTH00110034 on Town Highway 11 crossing Miles Stream, Concord, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.\nThe site is in the New England Upland section of the New England physiographic province \nin northeastern Vermont. The 24.9-mi2\n drainage area is in a predominantly rural and \nforested basin. In the vicinity of the study site, the surface cover is shrub and brush on the \nleft bank upstream and downstream of the bridge. The surface cover on the right bank \nupstream is pasture while downstream it is forest.\nIn the study area, Miles Stream has an incised, sinuous channel with a slope of \napproximately 0.005 ft/ft, an average channel top width of 48 ft and an average bank height \nof 4 ft. The channel bed material ranges from gravel to boulder with a median grain size \n(D50) of 102 mm (0.335 ft). The geomorphic assessment at the time of the Level I and Level \nII site visit on August 15, 1995, indicated that the reach was stable.\nThe Town Highway 11 crossing of Miles Stream is a 38-ft-long, two-lane bridge consisting \nof one 36-foot concrete slab span (Vermont Agency of Transportation, written \ncommunication, March 16, 1995). The opening length of the structure parallel to the bridge \nface is 33.9 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The \nchannel is skewed approximately 20 degrees to the opening. The calculated opening-skewto-roadway is 25 degrees while the VTAOT determined opening-skew-to-roadway is 22 \ndegrees.\nThe scour countermeasures at the site included type-2 stone fill (less than 36 inches \ndiameter) along the entire base length of all four wingwalls, scattered in front of the left and \nright abutments, and along the downstream left and right banks. Also, there is type-3 stone \nfill (less than 48 inches diameter) along the upstream left and right banks. Additional \ndetails describing conditions at the site are included in the Level II Summary and \nAppendices D and E.\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge is determined and analyzed as another potential worst-case scour scenario. Total \nscour at a highway crossing is comprised of three components: 1) long-term streambed \ndegradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow \narea at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.\nContraction scour for all modelled flows ranged from 0.0 to 1.3 ft. The worst-case \ncontraction scour occurred at the incipient roadway-overtopping discharge, which was less \nthan the 100-year discharge. The right abutment scour ranged from 7.4 to 9.6 ft while the \nleft abutment scour ranged from 12.8 to 14.4 ft. The worst-case abutment scour for the left \nand right abutments occurred at the 500-year discharge. Additional information on scour \ndepths and depths to armoring are included in the section titled “Scour Results”. Scouredstreambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. \nA cross-section of the scour computed at the bridge is presented in figure 8. Scour depths \nwere calculated assuming an infinite depth of erosive material and a homogeneous particlesize distribution. However, there is exposed bedrock in the channel upstream and \ndownstream of the bridge.\nUsually, computed scour depths are evaluated in combination with other information \nincluding (but not limited to) historical performance during flood events, the geomorphic \nstability assessment, existing scour protection measures, and the results of the hydraulic \nanalyses. Therefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97776","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Burns, R.L., and Hammond, R.E., 1997, Level II scour analysis for Bridge 34 (CONCTH00110034) on Town Highway 11, crossing Miles Stream, Concord, Vermont: U.S. Geological Survey Open-File Report 97-776, iv, 51 p., https://doi.org/10.3133/ofr97776.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176810,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97776.PNG"},{"id":279667,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0776/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Concord","otherGeospatial":"Miles Stream","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b18e4b07f02db6a7363","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240633,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hammond, Robert E.","contributorId":61862,"corporation":false,"usgs":true,"family":"Hammond","given":"Robert","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":240632,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50013,"text":"ofr97779 - 1997 - Level II scour analysis for Bridge 27 (STJOTH00080027) on Town Highway 8, crossing the Sleepers River, St. Johnsbury, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T14:40:15","indexId":"ofr97779","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-779","title":"Level II scour analysis for Bridge 27 (STJOTH00080027) on Town Highway 8, crossing the Sleepers River, St. Johnsbury, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nSTJOTH00080027 on Town Highway 8 crossing the Sleepers River, \nSt. Johnsbury, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the \nsite, including a quantitative analysis of stream stability and scour (U.S. Department of \nTransportation, 1993). Results of a Level I scour investigation also are included in \nAppendix E of this report. A Level I investigation provides a qualitative geomorphic \ncharacterization of the study site. Information on the bridge, gleaned from Vermont Agency \nof Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II \nanalyses and is found in Appendix D.\nThe site is in the New England Upland section of the New England physiographic province \nin northeastern Vermont. The 40.4-mi2\n drainage area is in a predominantly rural and \nforested basin. In the vicinity of the study site, the surface cover is forest on the upstream \nright bank with some pasture on the upstream left bank. The downstream right overbank \ncover is comprised of cut grass, trees and shrubs while the immediate banks have dense \nwoody vegetation. The downstream left bank is forested with some pasture.\nIn the study area, the Sleepers River has an incised, sinuous channel with a slope of \napproximately 0.007 ft/ft, an average channel top width of 72 ft and an average bank height \nof 5 ft. The channel bed material ranges from gravel to cobble with a median grain size \n(D50) of 48.5 mm (0.159 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on August 10, 1995, indicated that the reach was stable.\nThe Town Highway 8 crossing of the Sleepers River is a 74-ft-long, two-lane bridge \nconsisting of one 71-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, March 28, 1995). The opening length of the structure parallel to the bridge \nface is 68 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The \nchannel is skewed approximately 50 degrees to the opening while the computed openingskew-to-roadway is 45 degrees. The VTAOT database states the opening-skew-to-roadway \nas 30 degrees.\nA scour hole 2.5 ft deeper than the mean thalweg depth was observed along the right \nabutment during the Level I assessment. There is also a three to four foot deep scour hole in \nthe channel adjacent to the upstream right wingwall. The scour protection at the site \nincluded type-3 stone fill (less than 48 inches diameter) at the upstream end of the upstream \nleft wingwall, at the downstream end of the downstream right wingwall, and along the \ndownstream left bank. There was also type-2 stone fill (less than 36 inches diameter) at the \ndownstream end of the downstream left wingwall, along the upstream left bank, and along \nthe downstream right bank. Additional details describing conditions at the site are included \nin the Level II Summary and Appendices D and E.\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge is determined and analyzed as another potential worst-case scour scenario. Total \nscour at a highway crossing is comprised of three components: 1) long-term streambed \ndegradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow \narea at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.\nContraction scour computed for all modelled flows was zero ft. Abutment scour ranged \nfrom 6.2 to 9.7 ft. The worst-case abutment scour occurred at the 100-year discharge at the \nright abutment and at the 500-year discharge at the left abutment. Additional information on \nscour depths and depths to armoring are included in the section titled “Scour Results”. \nScoured-streambed elevations, based on the calculated scour depths, are presented in tables \n1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour \ndepths were calculated assuming an infinite depth of erosive material and a homogeneous \nparticle-size distribution. \nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97779","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Administration","usgsCitation":"Ivanoff, M.A., 1997, Level II scour analysis for Bridge 27 (STJOTH00080027) on Town Highway 8, crossing the Sleepers River, St. Johnsbury, Vermont: U.S. Geological Survey Open-File Report 97-779, iv, 51 p., https://doi.org/10.3133/ofr97779.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176811,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97779.PNG"},{"id":279666,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0779/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"St. Johnsbury","otherGeospatial":"Sleepers River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.25,44.375 ], [ -72.25,44.5 ], [ -72.0,44.5 ], [ -72.0,44.375 ], [ -72.25,44.375 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a7fe8","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240634,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":50014,"text":"ofr97780 - 1997 - Level II scour analysis for Bridge 36 (STOWTH00430036) on Town Highway 43, crossing Miller Brook, Stowe, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T13:11:16","indexId":"ofr97780","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-780","title":"Level II scour analysis for Bridge 36 (STOWTH00430036) on Town Highway 43, crossing Miller Brook, Stowe, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure STOWTH00430036 on Town Highway 43 crossing the Miller Brook, Stowe, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.
The site is in the Green Mountain section of the New England physiographic province in north central Vermont. The 5.5-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is predominantly forested.
In the study area, the Miller Brook has an incised, sinuous channel with a slope of approximately 0.03 ft/ft, an average channel top width of 43 ft and an average bank height of 7 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 70.4 mm (0.231 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 15, 1996, indicated that the reach was stable.
The Town Highway 43 crossing of the Miller Brook is a 24-ft-long, two-lane bridge consisting of one 21-foot steel-beam span (Vermont Agency of Transportation, written communication, October 13, 1995). The opening length of the structure parallel to the bridge face is 21.5 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 10 degrees to the opening and the computed opening-skew-to-roadway is also 10 degrees.
The footing on the left abutment was exposed 2.5 ft and the footing on the right abutment was exposed 3.0 ft during the Level I assessment. Scour protection measures at the site were type-4 stone fill (less than 60 inches diameter) on the left and right bank upstream, type-3 stone fill (less than 48 inches diameter) along the entire base length of the upstream right wingwall, right abutment, and type-2 stone fill (less than 36 inches diameter) along the entire base length of the downstream right wingwall, and left and right banks downstream. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.
Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge is determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for all modelled flows ranged from 0.0 to 0.9 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 3.1 to 6.5 ft. The worst-case abutment scour occurred at the 100-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.
It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97780","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Striker, L.K., and Wild, E.C., 1997, Level II scour analysis for Bridge 36 (STOWTH00430036) on Town Highway 43, crossing Miller Brook, Stowe, Vermont: U.S. Geological Survey Open-File Report 97-780, iv, 51 p., https://doi.org/10.3133/ofr97780.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176812,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97780.PNG"},{"id":279665,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0780/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Stowe","otherGeospatial":"Miller Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.875,44.375 ], [ -72.875,44.5 ], [ -72.75,44.5 ], [ -72.75,44.375 ], [ -72.875,44.375 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a638b","contributors":{"authors":[{"text":"Striker, Lora K.","contributorId":41481,"corporation":false,"usgs":true,"family":"Striker","given":"Lora","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":240636,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Wild, Emily C. 0000-0001-6157-7629 ecwild@usgs.gov","orcid":"https://orcid.org/0000-0001-6157-7629","contributorId":1810,"corporation":false,"usgs":true,"family":"Wild","given":"Emily","email":"ecwild@usgs.gov","middleInitial":"C.","affiliations":[{"id":5081,"text":"Libraries","active":false,"usgs":true}],"preferred":false,"id":240635,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ]}