This report provides the results of a detailed Level II analysis of scour potential at structure \nANDOVT00110040 on State Route 11 crossing Lyman Brook, Andover, Vermont (figures \n1–8). A Level II study is a basic engineering analysis of the site, including a quantitative \nanalysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of \na Level I scour investigation also are included in Appendix E of this report. A Level I \ninvestigation provides a qualitative geomorphic characterization of the study site. \nInformation on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) \nfiles, was compiled prior to conducting Level I and Level II analyses and is found in \nAppendix D.
\nThe site is in the Green Mountain section of the New England physiographic province in \nsouth-central Vermont. The 4.18-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is pasture while the immediate \nbanks have dense woody vegetation.
\nIn the study area, Lyman Brook has an incised, straight channel with a slope of \napproximately 0.03 ft/ft, an average channel top width of 42 ft and an average bank height \nof 8 ft. The channel bed material ranges from gravel to boulder with a median grain size \n(D50) of 86.0 mm (0.282 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on September 9, 1996, indicated that the reach was stable.
\nThe State Route 11 crossing of Lyman Brook is a 28-ft-long, two-lane bridge consisting of \none 27-foot concrete tee-beam span (Vermont Agency of Transportation, written \ncommunication, March 29, 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 0 degrees to the opening while the opening-skew-to-roadway is 30 degrees.
\nThe scour protection measures at the site included type-2 stone fill (less than 36 inches \ndiameter) at the upstream end of the upstream right wingwall and the downstream ends of \nthe downstream left and right wingwalls. There was also a stone wall along the top of the \nleft bank from 36 to 76 feet upstream. 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). \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 0.7 ft. The worst-case \ncontraction scour occurred at the incipient-overtopping discharge which was more than the \n100-year discharge. Left abutment scour ranged from 1.2 to 7.5 ft. The worst-case left \nabutment scour occurred at the 500-year discharge. Right abutment scour ranged from 5.2 \nto 6.7 ft. The worst-case right abutment scour occurred at the 100-year discharge. \nAdditional information on scour depths and depths to armoring are included in the section \ntitled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, \nare presented in tables 1 and 2. A cross-section of the scour computed at the bridge is \npresented in figure 8. Scour depths were calculated assuming an infinite depth of erosive \nmaterial 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/ofr97594","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., and Burns, R.L., 1997, Level II scour analysis for Bridge 40 (ANDOVT00110040) on State Route 11, crossing Lyman Brook, Andover, Vermont: U.S. Geological Survey Open-File Report 97-594, iv, 51 p., https://doi.org/10.3133/ofr97594.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":175731,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97594.GIF"},{"id":279713,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0594/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Andover","otherGeospatial":"Lyman Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.25 ], [ -72.75,43.375 ], [ -72.625,43.375 ], [ -72.625,43.25 ], [ -72.75,43.25 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a646a","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240552,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240553,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49967,"text":"ofr97627 - 1997 - Level II scour analysis for Bridge 5 (DUMMVT00300005) on State Route 30, crossing Stickney Brook, Dummerston, Vermont","interactions":[],"lastModifiedDate":"2013-12-18T13:01:47","indexId":"ofr97627","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":"97-627","title":"Level II scour analysis for Bridge 5 (DUMMVT00300005) on State Route 30, crossing Stickney Brook, Dummerston, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nDUMMVT00300005 on State Route 30 crossing Stickney Brook, Dummerston, 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 southeastern Vermont. The 6.31-mi2\n drainage area is in a predominantly rural and \nforested basin. In the vicinity of the study site, the surface cover is forest and brush.
\nIn the study area, Stickney Brook has an incised, straight channel with a slope of \napproximately 0.04 ft/ft, an average channel top width of 80 ft and an average bank height \nof 7 ft. The channel bed material is predominantly cobble with a median grain size (D50) of \n80.3 mm (0.264 ft). The geomorphic assessment at the time of the Level I and Level II site \nvisit on August 12, 1996, indicated that the reach was aggrading.
\nThe State Route 30 crossing of Stickney Brook is a 84-ft-long, two-lane bridge consisting of \none 82-foot steel-beam span (Vermont Agency of Transportation, written communication, \nMarch 30, 1995). The opening length of the structure parallel to the bridge face is 79.7 ft. \nThe bridge is supported by vertical, concrete abutments with spill-through embankments. \nThe channel is skewed approximately 5 degrees to the opening while the opening-skew-to-roadway is 0 degrees.
\nA scour hole 0.5 ft deeper than the mean thalweg depth was observed along the toe of the \nright spill-through slope during the Level I assessment. The scour protection measures at \nthe site were type-2 stone fill (less than 36 inches diameter) along the left and right bank \nunder the bridge forming a spill-through slope and type-2 stone fill from approximately 20 \nft to 64 ft upstream on the right bank. 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 0.0 to 0.2 ft. The worst-case \ncontraction scour occurred at the 100-year discharge. Left abutment scour ranged from 5.5 \nto 6.3 ft. Right abutment scour ranged from 2.0 to 3.8 ft. The worst-case abutment scour \noccurred at the 500-year 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.
\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/ofr97627","usgsCitation":"Ivanoff, M.A., 1997, Level II scour analysis for Bridge 5 (DUMMVT00300005) on State Route 30, crossing Stickney Brook, Dummerston, Vermont: U.S. Geological Survey Open-File Report 97-627, iv, 48 p., https://doi.org/10.3133/ofr97627.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":175733,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97627.GIF"},{"id":279711,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0627/report.pdf"}],"scale":"25000","country":"United States","state":"Vermont","city":"Dummerston","otherGeospatial":"Stickney Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,42.875 ], [ -72.75,43.0 ], [ -72.5,43.0 ], [ -72.5,42.875 ], [ -72.75,42.875 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a5f8a","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240556,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":49972,"text":"ofr97647 - 1997 - Level II scour analysis for Bridge 53 (CAMBTH00750053) on Town Highway 75, crossing the Brewster River, Cambridge, Vermont","interactions":[],"lastModifiedDate":"2013-12-18T11:19:05","indexId":"ofr97647","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":"97-647","title":"Level II scour analysis for Bridge 53 (CAMBTH00750053) on Town Highway 75, crossing the Brewster River, Cambridge, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nCAMBTH00750053 on Town Highway 75 crossing the Brewster River, Cambridge, \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 Green Mountain section of the New England physiographic province in \nnorthwestern Vermont. The 4.30-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 for the downstream \nright overbank area which has a barn surrounded by grass and shrubs.
\nIn the study area, the Brewster River has an incised, straight channel with a slope of \napproximately 0.05 ft/ft, an average channel top width of 62 ft and an average bank height \nof 12 ft. The channel bed material ranges from gravel to boulder with a median grain size \n(D50) of 84.4 mm (0.277 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on July 11, 1995, indicated that the reach was stable.
\nThe Town Highway 75 crossing of the Brewster River is a 28-ft-long, two-lane bridge \nconsisting of one 24-foot concrete tee-beam span (Vermont Agency of Transportation, \nwritten communication, March 8, 1995). The opening length of the structure parallel to the \nbridge face is 22.4 ft. The bridge is supported by vertical, concrete abutments with \nwingwalls. The channel is skewed approximately 40 degrees to the opening while the \nopening-skew-to-roadway as surveyed is 10 degrees.
\nA scour hole 1 ft deeper than the mean thalweg depth was observed along the left abutment \nduring the Level I assessment. The scour counter-measures at the site included type-3 stone \nfill (less than 48 inches diameter) along the entire base length of the upstream left wingwall. \nThere was also type-4 stone fill (less than 60 inches diameter) along the downstream end of \nthe downstream right wingwall. 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 1.1 to 1.4 ft. The worst-case \ncontraction scour occurred at the 100-year discharge. Abutment scour ranged from 10.7 to \n17.3 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/ofr97647","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 53 (CAMBTH00750053) on Town Highway 75, crossing the Brewster River, Cambridge, Vermont: U.S. Geological Survey Open-File Report 97-647, 50 p., https://doi.org/10.3133/ofr97647.","productDescription":"50 p.","costCenters":[],"links":[{"id":175838,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97647.GIF"},{"id":279706,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0647/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Cambridge","otherGeospatial":"Brewster River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.875,44.5 ], [ -72.875,44.625 ], [ -72.75,44.625 ], [ -72.75,44.5 ], [ -72.875,44.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a5b01","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240563,"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":240564,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49973,"text":"ofr97648 - 1997 - Level II scour analysis for Bridge 28 (CAMBTH00460028) on Town Highway 46, crossing the Seymour River, Cambridge, Vermont","interactions":[],"lastModifiedDate":"2013-12-18T10:57:25","indexId":"ofr97648","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":"97-648","title":"Level II scour analysis for Bridge 28 (CAMBTH00460028) on Town Highway 46, crossing the Seymour River, Cambridge, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nCAMBTH00460028 on Town Highway 46 crossing the Seymour River, Cambridge, \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 Green Mountain section of the New England physiographic province in \nnorthwestern Vermont. The 9.94-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is pasture while the immediate \nbanks have dense woody vegetation.
\nIn the study area, the Seymour River has an incised, straight channel with a slope of \napproximately 0.02 ft/ft, an average channel top width of 81 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 62.0 mm (0.204 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on July 11, 1995, indicated that the reach was stable.
\nThe Town Highway 46 crossing of the Seymour River is a 38-ft-long, one-lane bridge \nconsisting of one 33-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, March 8, 1995). The opening length of the structure parallel to the bridge \nface is 30.6 ft.The bridge is supported by vertical, concrete abutments with wingwalls. The \nchannel is skewed approximately 5 degrees to the opening while the measured opening-skew-to-roadway is 10 degrees.
\nA scour hole 0.2 ft deeper than the mean thalweg depth was observed along the upstream \nright wingwall and right abutment during the Level I assessment. The only scour protection \nmeasure at the site was type-1 stone fill (less than 12 inches diameter) along the upstream \nleft road embankment. Additional details describing conditions at the site are included in \nthe 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 0.0 to 0.8 ft. The worst-case \ncontraction scour occurred at the incipient roadway-overtopping discharge. Left abutment \nscour ranged from 4.2 to 4.9 ft. The worst-case left abutment scour occurred at the 500-year \ndischarge. Right abutment scour ranged from 8.8 to 9.7 ft. The worst-case right abutment \nscour occurred at the incipient roadway-overtopping 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/ofr97648","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., 1997, Level II scour analysis for Bridge 28 (CAMBTH00460028) on Town Highway 46, crossing the Seymour River, Cambridge, Vermont: U.S. Geological Survey Open-File Report 97-648, iv, 50 p., https://doi.org/10.3133/ofr97648.","productDescription":"iv, 50 p.","numberOfPages":"55","costCenters":[],"links":[{"id":175839,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97648.GIF"},{"id":279705,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0648/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Cambridge","otherGeospatial":"Seymour River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.875,44.5 ], [ -72.875,44.625 ], [ -72.75,44.625 ], [ -72.75,44.5 ], [ -72.875,44.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a7fc0","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240565,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":49974,"text":"ofr97649 - 1997 - Level II scour analysis for Bridge 38 (TOPSTH00570038) on Town Highway 57, crossing Waits River, Topsham, Vermont","interactions":[],"lastModifiedDate":"2013-12-18T10:48:55","indexId":"ofr97649","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":"97-649","title":"Level II scour analysis for Bridge 38 (TOPSTH00570038) on Town Highway 57, crossing Waits River, Topsham, Vermont","docAbstract":"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":49980,"text":"ofr97659 - 1997 - Level II scour analysis for Bridge 44 (LINCTH00330044) on Town Highway 33, crossing the New Haven River, Lincoln, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T12:44:40","indexId":"ofr97659","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":"97-659","title":"Level II scour analysis for Bridge 44 (LINCTH00330044) on Town Highway 33, crossing the New Haven River, Lincoln, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure LINCTH00330044 on Town Highway 33 crossing the New Haven River, Lincoln, 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 west-central Vermont. The 6.3-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest.
In the study area, the New Haven River has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 56 ft and an average bank height of 6 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 101.9 mm (0.334 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 10, 1996, indicated that the reach was stable.
The Town Highway 33 crossing of the New Haven River is a 33-ft-long, one-lane bridge consisting of one 31-foot timber-beam span (Vermont Agency of Transportation, written communication, December 14, 1995). The opening length of the structure parallel to the bridge face is 29.3 ft. The bridge is supported by vertical, wood-beam crib abutments with wingwalls. The channel is skewed approximately 25 degrees to the opening while the opening-skew-to-roadway is zero degrees.
A scour hole 1.0 ft deeper than the mean thalweg depth was observed along the right abutment during the Level I assessment. The scour protection measures at the site included type-1 stone fill (less than 12 inches diameter) at the downstream end of the downstream left wingwall and along the downstream right bank, type-2 stone fill (less than 36 inches diameter) along the upstream right bank and type-3 stone fill (less than 48 inches diameter) at the upstream end of the upstream right 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. 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 1.3 ft. The worst-case contraction scour occurred at the incipient roadway-overtopping discharge, which was less than the 100-year discharge. Abutment scour ranged from 9.4 to 12.6 ft. The worst-case abutment scour occurred at the 100-year discharge for the left abutment and at the incipient overtopping discharge for the right abutment. 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/ofr97659","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Burns, R.L., and Wild, E.C., 1997, Level II scour analysis for Bridge 44 (LINCTH00330044) on Town Highway 33, crossing the New Haven River, Lincoln, Vermont: U.S. Geological Survey Open-File Report 97-659, iv, 51 p., https://doi.org/10.3133/ofr97659.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176147,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97659.GIF"},{"id":279698,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0659/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Lincoln","otherGeospatial":"New Haven 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":"4f4e4b17e4b07f02db6a611a","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240576,"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":240575,"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":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":240583,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49880,"text":"ofr97105 - 1997 - Level II scour analysis for Bridge 6 (MORRTH00030006) on Town Highway 3, crossing Ryder Brook, Morristown, Vermont","interactions":[],"lastModifiedDate":"2014-01-07T11:42:39","indexId":"ofr97105","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":"97-105","title":"Level II scour analysis for Bridge 6 (MORRTH00030006) on Town Highway 3, crossing Ryder Brook, Morristown, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nMORRTH00030006 on Town Highway 3 crossing Ryder Brook, Morristown, 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 \nnorth-central Vermont. The 19.1-mi2 drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover also is forested.
\nIn the study area, Ryder Brook has a straight channel with an average channel top width of \n450 ft and an average bank height of 7 ft. The predominant channel bed material is silt and \nclay with a median grain size (D50) of 0.0719 mm (0.000236 ft). The geomorphic \nassessment at the time of the Level I and Level II site visit on July 18, 1996, indicated that \nthe reach was aggraded, but the channel through the bridge was scoured.
\nThe Town Highway 3 crossing of Ryder Brook is a 72-ft-long, two-lane bridge consisting \nof one 70-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, January 31, 1996). The bridge is supported by vertical, concrete abutments \nwith spill-through embankments and wingwalls. The channel is not skewed to the opening \nand the opening-skew-to-roadway is zero degrees.
\nChannel scour under the bridge was evident at this site during the Level I assessment. The \ndepth of the channel increases from 3 feet at the upstream bridge face to 10 feet at the \ndownstream bridge face. The only scour protection measure at the site was type-2 stone fill \n(less than 36 inches diameter) on the spill-through embankments of each abutment, the \nupstream road embankments and the downstream left road embankment. Additional details \ndescribing conditions at the site are included in the Level II Summary and Appendices D \nand E.
\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a \nhighway crossing is comprised of three components: 1) long-term streambed degradation; \n2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) \nand; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is \nthe sum of the three components. Equations are available to compute depths for contraction \nand local scour and a summary of the results of these computations follows.
\nContraction scour for all modelled flows ranged from 20.4 to 25.8 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 8.3 to \n10.5 ft. The worst-case abutment scour also 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/ofr97105","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Boehmler, E.M., and Hammond, R.E., 1997, Level II scour analysis for Bridge 6 (MORRTH00030006) on Town Highway 3, crossing Ryder Brook, Morristown, Vermont: U.S. Geological Survey Open-File Report 97-105, iv, 48 p., https://doi.org/10.3133/ofr97105.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":170106,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97105.GIF"},{"id":279822,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0105/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Morristown","otherGeospatial":"Ryder 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":"4f4e4b17e4b07f02db6a5bb9","contributors":{"authors":[{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240411,"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":240410,"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":5540,"text":"fs08297 - 1997 - The National Atlas of the United States of America","interactions":[{"subject":{"id":5540,"text":"fs08297 - 1997 - The National Atlas of the United States of America","indexId":"fs08297","publicationYear":"1997","noYear":false,"title":"The National Atlas of the United States of America"},"predicate":"SUPERSEDED_BY","object":{"id":5541,"text":"fs08200 - 2000 - The National Atlas of the United States of America","indexId":"fs08200","publicationYear":"2000","noYear":false,"title":"The National Atlas of the United States of America"},"id":1}],"supersededBy":{"id":5541,"text":"fs08200 - 2000 - The National Atlas of the United States of America","indexId":"fs08200","publicationYear":"2000","noYear":false,"title":"The National Atlas of the United States of America"},"lastModifiedDate":"2014-04-03T08:54:13","indexId":"fs08297","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":313,"text":"Fact Sheet","code":"FS","onlineIssn":"2327-6932","printIssn":"2327-6916","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"082-97","title":"The National Atlas of the United States of America","docAbstract":"In 1970 the U.S. Geological Survey \n(USGS) published The National Atlas of \nthe United States of America™. It was a \n400-page, oversized, 12-pound collection \nof maps. In 1998, a new and innovative \nNational Atlas will be published. This \nedition will include both electronic and \npaper map products and will exploit \ninformation management, access, and \ndelivery technologies that didn't exist in \n1970.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/fs08297","usgsCitation":"Water Resources Division, U.S. Geological Survey, 1997, The National Atlas of the United States of America (Retired Edition, Superseded by FS 082-00): U.S. Geological Survey Fact Sheet 082-97, 2 p., https://doi.org/10.3133/fs08297.","productDescription":"2 p.","numberOfPages":"2","costCenters":[],"links":[{"id":139380,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/fs08297.jpg"},{"id":285372,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/fs/0082-97/report.pdf"}],"edition":"Retired Edition, Superseded by FS 082-00","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4ac7e4b07f02db67b11c","contributors":{"authors":[{"text":"Water Resources Division, U.S. Geological Survey","contributorId":128075,"corporation":true,"usgs":false,"organization":"Water Resources Division, U.S. Geological Survey","id":528643,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"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":49881,"text":"ofr97106 - 1997 - Level II scour analysis for Bridge 11 (HINETH00040011) on Town Highway 4, crossing Lewis Creek, Hinesburg, Vermont","interactions":[],"lastModifiedDate":"2014-01-07T11:35:22","indexId":"ofr97106","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":"97-106","title":"Level II scour analysis for Bridge 11 (HINETH00040011) on Town Highway 4, crossing Lewis Creek, Hinesburg, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nHINETH00040011 on Town Highway 4 crossing Lewis Creek, Hinesburg, 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 \nnorthwestern Vermont. The 38.4-mi2 drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is pasture.
\nIn the study area, Lewis Creek has an incised, straight channel with a slope of \napproximately 0.001 ft/ft, an average channel top width of 60 ft and an average channel \ndepth of 7 ft. The channel bed material ranges from gravel to boulder with a median grain \nsize (D50) of 47.0 mm (0.154 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on July 3, 1996, indicated that the reach was stable.
\nThe Town Highway 4 crossing of Lewis Creek is an 84-foot-long, two-lane bridge \nconsisting of one 82-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, December 15, 1995). The bridge is supported by vertical, concrete \nabutments with wingwalls and spill-through embankments at each abutment. The channel is \nskewed approximately 40 degrees to the opening while the opening-skew-to-roadway is 15 \ndegrees.
\nThe scour protection measures at the site were type-2 stone fill (less than 36 inches \ndiameter) at the downstream left and right wingwalls and the downstream right bank. Scour \nprotection also included type-3 stone fill (less than 48 inches diameter) at the left and right \nupstream wingwalls, both abutments, both upstream banks, and the left bank downstream. \nAdditional details describing conditions at the site are included in the Level II Summary \nand Appendices D and E.
\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a \nhighway crossing is comprised of three components: 1) long-term streambed degradation; \n2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) \nand; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is \nthe sum of the three components. Equations are available to compute depths for contraction \nand local scour and a summary of the results of these computations follows.
\nContraction scour for all modelled flows ranged from 0.0 to 1.8 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Left abutment scour ranged from \n14.1 to 18.2 ft. Right abutment scour ranged from 9.9 to 13.4 ft. The worst-case abutment \nscour occurred at left abutment for the 500-year discharge. Additional information on scour \ndepths and depths to armoring are included in the section titled “Scour Results”. Scoured-\nstreambed 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-\nsize 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/ofr97106","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., and Burns, R.L., 1997, Level II scour analysis for Bridge 11 (HINETH00040011) on Town Highway 4, crossing Lewis Creek, Hinesburg, Vermont: U.S. Geological Survey Open-File Report 97-106, iv, 48 p., https://doi.org/10.3133/ofr97106.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":170107,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97106.GIF"},{"id":279821,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0106/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Hinesburg","otherGeospatial":"Lewis Creek","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -73.125,44.25 ], [ -73.125,44.375 ], [ -73.0,44.375 ], [ -73.0,44.25 ], [ -73.125,44.25 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a840a","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240412,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240413,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49882,"text":"ofr97107 - 1997 - Level II scour analysis for Bridge 108 (STJOUS00020108) on U.S. Highway 2, crossing the Moose River, St. Johnsbury, Vermont","interactions":[],"lastModifiedDate":"2014-01-07T11:25:24","indexId":"ofr97107","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":"97-107","title":"Level II scour analysis for Bridge 108 (STJOUS00020108) on U.S. Highway 2, crossing the Moose River, St. Johnsbury, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nSTJOUS00020108 on U.S. Highway 2 crossing the Moose 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/White Mountain sections of the New England \nphysiographic province in north-east Vermont. The 117-mi2 drainage area is in a \npredominantly rural and forested basin. In the vicinity of the study site, the surface cover is \npasture on the upstream right bank, forest on the upstream left bank, shrub and brush on the \ndownstream left bank, and forest on the downstream right bank.
\nIn the study area, the Moose River has an incised, sinuous channel with a slope of \napproximately 0.008 ft/ft, an average channel top width of 96 ft and an average channel \ndepth of 6 ft. The predominant channel bed material is cobble with a median grain size \n(D50) of 94.1 mm (0.309 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on August 14, 1995, indicated that the reach was stable.
\nThe U.S. Highway 2 crossing of the Moose River is a 103-ft-long, two-lane bridge \nconsisting of three spans with a maximum 57-foot concrete T-beam span (Vermont Agency \nof Transportation, written communication, March 28, 1995). The bridge is supported by \ntwo piers, and vertical, concrete abutments with no wingwalls. The channel is skewed \napproximately 10 degrees to the opening while the opening-skew-to-roadway is 0 degrees.
\nThe scour protection measures at the site were type-2 stone fill (less than 36 inches \ndiameter) at the upstream and downstream channel banks. There is also type-3 stone fill \n(less than 48 inches diameter) at both the upstream and downstream ends of the left and \nright abutments. Additional details describing conditions at the site are included in the \nLevel II Summary and Appendices D and E.
\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a \nhighway crossing is comprised of three components: 1) long-term streambed degradation; \n2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) \nand; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is \nthe sum of the three components. Equations are available to compute depths for contraction \nand local scour and a summary of the results of these computations follows.
\nContraction scour for all modelled flows ranged from 0.0 to 0.4 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 9.3 to \n12.2 ft. The worst-case abutment scour occurred at the left abutment 500-year discharge. \nPier scour ranged from 8.3 to 15.7 for both piers. The worst case pier scour occurred at the \nleft pier, for the 100-year discharge analysis. Additional in formation on scour depths and \ndepths to armoring are included in the section titled “Scour Results”. Scoured-streambed \nelevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-\nsection of the scour computed at the bridge is presented in figure 8. Scour depths were \ncalculated assuming an infinite depth of erosive material and a homogeneous particle-size \ndistribution.
\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/ofr97107","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., 1997, Level II scour analysis for Bridge 108 (STJOUS00020108) on U.S. Highway 2, crossing the Moose River, St. Johnsbury, Vermont: U.S. Geological Survey Open-File Report 97-107, iv, 50 p., https://doi.org/10.3133/ofr97107.","productDescription":"iv, 50 p.","numberOfPages":"55","costCenters":[],"links":[{"id":170108,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97107.GIF"},{"id":279820,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0107/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"St. Johnsbury","otherGeospatial":"Moose River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.0,44.375 ], [ -72.0,44.5 ], [ -71.875,44.5 ], [ -71.875,44.375 ], [ -72.0,44.375 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a842c","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240414,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":49883,"text":"ofr97108 - 1997 - Level II scour analysis for Bridge 12 (FFIETH00030012) on Town Highway 3, crossing the Fairfield River, Fairfield, Vermont","interactions":[],"lastModifiedDate":"2014-01-07T11:15:15","indexId":"ofr97108","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":"97-108","title":"Level II scour analysis for Bridge 12 (FFIETH00030012) on Town Highway 3, crossing the Fairfield River, Fairfield, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nFFIETH00030012 on Town Highway 3 crossing the Fairfield River, Fairfield, 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 \nnorth-western Vermont. The 7.34-mi2 drainage area is in a predominantly rural basin with \nforest on the valley walls and pasture/row crops on the valley bottom. In the vicinity of the \nstudy site, the surface cover is row crops with a few trees on the immediate banks.
\nIn the study area, the Fairfield River has a meandering channel with a slope of \napproximately 0.005 ft/ft, an average channel top width of 37 ft and an average channel \ndepth of 6 ft. The predominant channel bed materials are sand and gravel with a median \ngrain size (D50) of 32.5 mm (0.107 ft). The geomorphic assessment at the time of the Level \nI and Level II site visit on June 16, 1995, indicated that the reach was stable.
\nThe Town Highway 3 crossing of the Fairfield River is a 24-ft-long, one-lane bridge \nconsisting of one 20-foot concrete span (Vermont Agency of Transportation, written \ncommunication, March 8, 1995). The bridge is supported by vertical, concrete abutments \nwith wingwalls. The channel is skewed approximately 40 degrees to the opening. Although \nbridge records show an opening-skew-to-roadway of 45 degrees, the skew measured from \nsurveyed points was 30 degrees.
\nAt the time of the level I assessment, the left abutment had been undermined and settled \ninto a scour hole at the upstream end. The right abutment footing was exposed but not \nundermined. The scour protection measures at the site were type-1 stone fill (less than 12 \ninches diameter) on the downstream right bank, and type-2 stone fill (less than 36 inches \ndiameter) along the entire base of the upstream right wingwall, the upstream banks, and\ndownstream left bank. The type-2 stone fill on the left bank downstream changes to type-1 \nabout 55 feet downstream of the bridge. Additional details describing conditions at the site \nare included in the Level II Summary and Appendices D and E.
\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a \nhighway crossing is comprised of three components: 1) long-term streambed degradation; \n2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) \nand; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is \nthe sum of the three components. Equations are available to compute depths for contraction \nand local scour and a summary of the results of these computations follows.
\nContraction scour for all modelled flows ranged from 1.6 to 3.0 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 3.2 to \n4.0 ft. at the left abutment and 9.7 to 11.7 feet at the right abutment. The worst-case left \nabutment scour occurred at the incipient over-topping discharge, which was less than the \n100-year discharge. The worst-case right abutment scour occurred at the 500-year \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/ofr97108","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Boehmler, E.M., and Degnan, J.R., 1997, Level II scour analysis for Bridge 12 (FFIETH00030012) on Town Highway 3, crossing the Fairfield River, Fairfield, Vermont: U.S. Geological Survey Open-File Report 97-108, iv, 52 p., https://doi.org/10.3133/ofr97108.","productDescription":"iv, 52 p.","numberOfPages":"57","costCenters":[],"links":[{"id":170109,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97108.GIF"},{"id":279819,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0108/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Fairfield","otherGeospatial":"Fairfield River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -73.0,44.75 ], [ -73.0,44.875 ], [ -72.875,44.875 ], [ -72.875,44.75 ], [ -73.0,44.75 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a83cc","contributors":{"authors":[{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240416,"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":240415,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49884,"text":"ofr97109 - 1997 - Level II scour analysis for Bridge 9 (BARRUSO3020009) on U.S. Route 302, crossing Jail Branch, Barre, Vermont","interactions":[],"lastModifiedDate":"2014-01-07T10:59:16","indexId":"ofr97109","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":"97-109","title":"Level II scour analysis for Bridge 9 (BARRUSO3020009) on U.S. Route 302, crossing Jail Branch, Barre, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nBARRUS03020009 on U.S. Route 302 crossing Jail Branch, Barre, Vermont (figures 1–8). \nA Level II study is a basic engineering analysis of the site, including a quantitative analysis \nof stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level \nI scour investigation also are included in Appendix E of this report. A Level I investigation \nprovides a qualitative geomorphic characterization of the study site. Information on the \nbridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled \nprior to conducting Level I and Level II analyses and is found in Appendix D.
\nThe site is in the New England Upland section of the New England physiographic province \nin central Vermont. The 42.8-mi2\n drainage area is in a predominantly rural and forested \nbasin. A flood control reservoir with a usable capacity of 525 million cubic feet is located \njust upstream of the bridge. In the vicinity of the study site, the surface cover left of the \nchannel consists of trees and brush. Right of the channel, the immediate bank is covered by \ntrees and brush while the overbank is grass covered with several buildings.
\nIn the study area, Jail Branch has an incised, sinuous channel with a slope of approximately \n0.008 ft/ft, an average channel top width of 86 ft and an average channel depth of 5 ft. The \nchannel bed material ranged from gravel to boulder with a median grain size (D50) of 73.5 \nmm (0.241 ft). The geomorphic assessment at the time of the Level I and Level II site visit \non July 17, 1996, indicated that the reach was laterally unstable due to its sinuosity, cut \nbanks, point bars, and extensive bank protection.
\nThe U.S. Route 302 crossing of Jail Branch is a 74-ft-long, two-lane bridge consisting of \none 72-foot steel-beam span (Vermont Agency of Transportation, written communication, \nOctober 13, 1995). The bridge is supported by vertical, concrete abutments with wingwalls. \nThe channel is skewed approximately 30 degrees to the opening while there is no opening-\nskew-to-roadway.
\nThere is evidence of channel scour along the right bank from 190 feet upstream of the \nbridge and extending through the bridge along the right abutment. Under the bridge, the \nscour depth is approximately 0.5 feet below the mean thalweg depth. Scour protection \nmeasures at the site include type-3 stone fill (less than 48 inches diameter) along the right \nbank extending from the bridge to 192 feet upstream. Type-2 stone fill (less than 36 inches \ndiameter) is along the right abutment and the right downstream bank to 205 feet downtream \nof the bridge. Additional details describing conditions at the site are included in the Level II \nSummary and Appendices D and E.
\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a \nhighway crossing is comprised of three components: 1) long-term streambed degradation; \n2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) \nand; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is \nthe sum of the three components. Equations are available to compute depths for contraction \nand local scour and a summary of the results of these computations follows.
\nContraction scour for all modelled flows ranged from 0.2 to 0.5 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 4.3 to \n7.5 ft. The worst-case abutment scour occurred at the 500-year discharge. Computed scour \nfor the 100-year event does not go below the abutment footings. 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/ofr97109","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Olson, S.A., and Ivanoff, M.A., 1997, Level II scour analysis for Bridge 9 (BARRUSO3020009) on U.S. Route 302, crossing Jail Branch, Barre, Vermont: U.S. Geological Survey Open-File Report 97-109, iv, 48 p., https://doi.org/10.3133/ofr97109.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":170110,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97109.GIF"},{"id":279818,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0109/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Barre","otherGeospatial":"Jail Branch","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.5,44.125 ], [ -72.5,44.25 ], [ -72.375,44.25 ], [ -72.375,44.125 ], [ -72.5,44.125 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b16e4b07f02db6a55f3","contributors":{"authors":[{"text":"Olson, Scott A. 0000-0002-1064-2125 solson@usgs.gov","orcid":"https://orcid.org/0000-0002-1064-2125","contributorId":2059,"corporation":false,"usgs":true,"family":"Olson","given":"Scott","email":"solson@usgs.gov","middleInitial":"A.","affiliations":[{"id":405,"text":"NH/VT office of New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240417,"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":240418,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49885,"text":"ofr97110 - 1997 - Level II scour analysis for Bridge 13 (PFRDTH00030013) on Town Highway 3, crossing Furnace Brook, Pittsford, Vermont","interactions":[],"lastModifiedDate":"2014-01-07T10:47:52","indexId":"ofr97110","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":"97-110","title":"Level II scour analysis for Bridge 13 (PFRDTH00030013) on Town Highway 3, crossing Furnace Brook, Pittsford, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nPFRDTH00030013 on Town Highway 3 crossing Furnace Brook, Pittsford, 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 western \nVermont. The 17.1-mi2\n drainage area is in a predominantly rural and forested basin. In the \nvicinity of the study site, the surface cover is grass along the downstream right bank while \nthe remaining banks are primarily forested.
\nIn the study area, Furnace Brook has an incised, sinuous channel with a slope of \napproximately 0.03 ft/ft, an average channel top width of 49 ft and an average channel \ndepth of 4 ft. The predominant channel bed material ranges from gravel to bedrock with a \nmedian grain size (D50) of 70.2 mm (0.230 ft). The geomorphic assessment at the time of \nthe Level I and Level II site visit on June 20, 1995, indicated that the reach was stable.
\nThe Town Highway 3 crossing of Furnace Brook is a 75-ft-long, two-lane bridge consisting \nof one 72-ft-long steel stringer span (Vermont Agency of Transportation, written \ncommunication, March 14, 1995). The bridge is supported by vertical, concrete abutments \nwith spill-through slopes. The channel is skewed approximately 20 degrees to the opening \nwhile the opening-skew-to-roadway is 35 degrees. The opening-skew-to-roadway was \ndetermined from surveyed data collected at the bridge although, information provided from \nthe VTAOT files, indicates that the opening-skew-to-roadway is 30 degrees (Appendix D).
\nThe scour protection measures at the site included type-2 stone fill (less than 36 inches \ndiameter) on the spill-through slope along each abutment. Type-2 stone fill scour protection \nwas also found along the upstream left wingwall and downstream right wingwall. Type-1 \n(less than 12 inches diameter) stone fill scour protection was found along the upstream right \nwingwall and downstream left wingwall. No bank protection was observed downstream or \nupstream. Additional details describing conditions at the site are included in the Level II \nSummary and Appendices D and E.
\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a \nhighway crossing is comprised of three components: 1) long-term streambed degradation; \n2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) \nand; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is \nthe sum of the three components. Equations are available to compute depths for contraction \nand local scour and a summary of the results of these computations follows.
\nContraction scour for all modelled flows ranged from 1.2 to 2.0 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 7.8 to \n13.1 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 although, bedrock outcropping is apparent both \nupstream and downstream of this 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/ofr97110","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Flynn, R.H., and Medalie, L., 1997, Level II scour analysis for Bridge 13 (PFRDTH00030013) on Town Highway 3, crossing Furnace Brook, Pittsford, Vermont: U.S. Geological Survey Open-File Report 97-110, iv, 50 p., https://doi.org/10.3133/ofr97110.","productDescription":"iv, 50 p.","numberOfPages":"55","costCenters":[],"links":[{"id":170111,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97110.GIF"},{"id":279817,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0110/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Pittsford","otherGeospatial":"Furnace Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -73.125,43.625 ], [ -73.125,43.75 ], [ -72.875,43.75 ], [ -72.875,43.625 ], [ -73.125,43.625 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8321","contributors":{"authors":[{"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":240419,"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":240420,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49913,"text":"ofr97341 - 1997 - Level II scour analysis for Bridge 2 (BENNCYPARK0002) on Park Street, crossing Furnace Brook, Bennington, Vermont","interactions":[],"lastModifiedDate":"2014-01-05T13:22:53","indexId":"ofr97341","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":"97-341","title":"Level II scour analysis for Bridge 2 (BENNCYPARK0002) on Park Street, crossing Furnace Brook, Bennington, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nBENNCYPARK0002 on the Park Street crossing of Furnace Brook, Bennington, 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 \nsouthwestern Vermont. The 12.8-mi2\n drainage area is a predominantly rural and forested \nbasin. The bridge site is located within an urban setting in the Town of Bennington with \nbuildings, homes, lawns, and pavement on the overbanks.
\nIn the study area, Furnace Brook has a mildly sinuous channel located on a delta and has a \nslope of approximately 0.01 ft/ft, an average channel top width of 35 ft and an average bank \nheight of 4 ft. The predominant channel bed materials are gravel and cobble with a median \ngrain size (D50) of 58.4 mm (0.192 ft). The geomorphic assessment at the time of the Level \nI and Level II site visit on August 6, 1996, indicated that the reach was unstable. However, \nin the immediate vicinity of the bridge the reach has been stabilized with bank protection. \nUpstream of the protection, there is bank cutting and channel scour.
\nThe Park Street crossing of Furnace Brook is a 29-ft-long, two-lane bridge consisting of one \n26-foot concrete span (Vermont Agency of Transportation, written communication, \nDecember 14, 1995). The width of the bridge opening parallel to the downstream bridge \nface is 25.3 feet. The bridge is supported by vertical, concrete abutments with no wingwalls. \nThe upstream channel is skewed approximately 45 degrees to the opening while the \nopening-skew-to-roadway is 10 degrees.
\nScour countermeasures at the site include type-2 stone fill (less than 36 inches diameter) on \nthe right banks upstream and downstream of the bridge and type-3 stone fill (less than 48 \ninches diameter) on the upstream left bank. Additional details describing conditions at the \nsite 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). \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.
\nThere was no contraction scour computed for any of the modelled flows. Computed left \nabutment scour ranged from 2.5 to 5.6 ft. with the worst-case scour occurring at the 500-\nyear discharge. Computed right abutment scour ranged from 5.6 to 8.4 ft. with the worst-\ncase scour also occurring at the 100-year discharge. Additional information on scour depths \nand depths to armoring are included in the section titled “Scour Results”. Scoured-\nstreambed 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-\nsize 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/ofr97341","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Olson, S.A., 1997, Level II scour analysis for Bridge 2 (BENNCYPARK0002) on Park Street, crossing Furnace Brook, Bennington, Vermont: U.S. Geological Survey Open-File Report 97-341, iv, 51 p., https://doi.org/10.3133/ofr97341.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":169722,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97341.GIF"},{"id":279772,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0341/report.pdf"}],"country":"United States","state":"Vermont","city":"Bennington","otherGeospatial":"Furnace Brook","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a81a3","contributors":{"authors":[{"text":"Olson, Scott A. 0000-0002-1064-2125 solson@usgs.gov","orcid":"https://orcid.org/0000-0002-1064-2125","contributorId":2059,"corporation":false,"usgs":true,"family":"Olson","given":"Scott","email":"solson@usgs.gov","middleInitial":"A.","affiliations":[{"id":405,"text":"NH/VT office of New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240467,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ]}