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":49986,"text":"ofr97671 - 1997 - Level II scour analysis for Bridge 34 (CORITH0050034) on Town Highway 50, crossing the South Branch Waits River, Corinth, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T14:49:46","indexId":"ofr97671","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":"97-671","title":"Level II scour analysis for Bridge 34 (CORITH0050034) on Town Highway 50, crossing the South Branch Waits River, Corinth, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nCORITH00500034 on Town Highway 50 crossing the South Branch Waits River, Corinth, \nVermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including \na quantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.
\nThe site is in the New England Upland section of the New England physiographic province \nin central Vermont. The 35.9-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is pasture upstream and downstream \nof the bridge while the immediate banks have dense woody vegetation.
\nIn the study area, the South Branch Waits River has an incised, meandering channel with a \nslope of approximately 0.005 ft/ft, an average channel top width of 63 ft and an average \nbank height of 6 ft. The channel bed material ranges from sand to cobble with a median \ngrain size (D50) of 23.7 mm (0.078 ft). The geomorphic assessment at the time of the Level \nI and Level II site visit on September 5, 1995, indicated that the reach was stable.
\nThe Town Highway 50 crossing of the South Branch Waits River is a 56-ft-long, one-lane \nbridge consisting of one 54-foot steel thru-truss span (Vermont Agency of Transportation, \nwritten communication, March 24, 1995). The opening length of the structure parallel to the \nbridge face is 51.5 ft.The bridge is supported by vertical, concrete abutments with no \nwingwalls. Stone fill and bank material in front of the abutments create spill-through \nembankments. The channel is skewed approximately 30 degrees to the opening while the \nopening-skew-to-roadway is 15 degrees.
\nA scour hole 2.5 ft deeper than the mean thalweg depth was observed along the left bank \nthrough the bridge during the Level I assessment. The only scour protection measure at the \nsite was type-2 stone fill (less than 36 inches diameter) along the left and right banks \nextending from upstream to downstream through the bridge. The stone fill under the bridge \ncreates spill-through embankments. 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) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge was determined and analyzed as other 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 3.0 ft. The worst-case \ncontraction scour occurred at the incipient roadway-overtopping discharge, which was less \nthan the 100-year discharge. Abutment scour ranged from 2.4 to 6.3 ft. The worst-case \nabutment scour occurred at the 500-year discharge. Additional information on scour depths \nand depths to armoring are included in the section titled “Scour Results”. 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 and HIRE equations (abutment scour) give \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/ofr97671","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., 1997, Level II scour analysis for Bridge 34 (CORITH0050034) on Town Highway 50, crossing the South Branch Waits River, Corinth, Vermont: U.S. Geological Survey Open-File Report 97-671, iv, 53 p., https://doi.org/10.3133/ofr97671.","productDescription":"iv, 53 p.","numberOfPages":"58","costCenters":[],"links":[{"id":176153,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97671.GIF"},{"id":279692,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0671/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Corinth","otherGeospatial":"South Branch Waits River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.25,44.0 ], [ -72.25,44.125 ], [ -72.125,44.125 ], [ -72.125,44.0 ], [ -72.25,44.0 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a6523","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240587,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":49985,"text":"ofr97670 - 1997 - Level II scour analysis for Bridge 34 (ROCHTH00210034) on Town Highway 21, crossing the White River, Rochester, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T14:29:11","indexId":"ofr97670","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":"97-670","title":"Level II scour analysis for Bridge 34 (ROCHTH00210034) on Town Highway 21, crossing the White River, Rochester, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure ROCHTH00210034 on Town Highway 21 crossing the White River, Rochester, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, obtained from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.
The site is in the Green Mountain section of the New England physiographic province in central Vermont. The 74.8-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is suburban on the upstream and downstream left overbanks, though brush prevails along the immediate banks. On the upstream and downstream right overbanks, the surface cover is pasture with brush and trees along the immediate banks.
In the study area, the White River has an incised, straight channel with a slope of approximately 0.002 ft/ft, an average channel top width of 102 ft and an average bank height of 5 ft. The channel bed material ranges from sand to cobble with a median grain size (D50) of 74.4 mm (0.244 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 23, 1996, indicated that the reach was stable.
The Town Highway 21 crossing of the White River is a 72-ft-long, two-lane bridge consisting of 70-foot steel stringer span (Vermont Agency of Transportation, written communication, March 22, 1995). The opening length of the structure parallel to the bridge face is 67.0 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 15 degrees to the opening while the opening-skew-to-roadway is zero degrees.
Channel scour, 1.5 ft deeper than the mean thalweg depth was observed along the left abutment and wingwalls during the Level I assessment. Scour countermeasures at the site includes type-1 stone fill (less than 12 inches diameter) along the upstream left bank and the upstream and downstream left road embankments, type-2 (less than 36 inches diameter) along the upstream end of the upstream left wingwall and downstream left bank, and type-3 (less than 48 inches diameter) along the downstream 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). In addition, the incipient roadway-overtopping discharge is analyzed since it has the potential of being the 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 discharges was zero. Left abutment scour ranged from 6.8 to 21.2 ft. Right abutment scour ranged from 13.9 to 18.4 ft. The worst-case abutment scour occurred at the 500-year discharge at the left and right abutments. 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/ofr97670","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., and Degnan, J., 1997, Level II scour analysis for Bridge 34 (ROCHTH00210034) on Town Highway 21, crossing the White River, Rochester, Vermont: U.S. Geological Survey Open-File Report 97-670, iv, 51 p., https://doi.org/10.3133/ofr97670.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176152,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97670.GIF"},{"id":279693,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0670/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Rochester","otherGeospatial":"White 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":"4f4e4b17e4b07f02db6a64f2","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":240585,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Degnan, James","contributorId":20398,"corporation":false,"usgs":true,"family":"Degnan","given":"James","affiliations":[],"preferred":false,"id":240586,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49984,"text":"ofr97664 - 1997 - Level II scour analysis for Bridge 33 (HUNTTH00220033) on Town Highway 22, crossing Brush Brook, Huntington, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T15:02:59","indexId":"ofr97664","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-664","title":"Level II scour analysis for Bridge 33 (HUNTTH00220033) on Town Highway 22, crossing Brush Brook, Huntington, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nHUNTTH00220033 on Town Highway 22 crossing Brush Brook, Huntington, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.
\nThe site is in the Green Mountain section of the New England physiographic province in \ncentral Vermont. The 8.65-mi2\n drainage area is in a predominantly rural and forested basin. \nIn the vicinity of the study site, the surface cover is forest except on the downstream right \noverbank which is pasture.
\nIn the study area, Brush Brook has an incised, straight channel with a slope of \napproximately 0.04 ft/ft, an average channel top width of 42 ft and an average bank height \nof 3 ft. The channel bed material ranges from gravel to boulder with a median grain size \n(D50) of 76.7 mm (0.252 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on June 26, 1996, indicated that the reach was stable.
\nThe Town Highway 22 crossing of Brush Brook is a 40-ft-long, two-lane bridge consisting \nof one 23.5-foot concrete slab span (Vermont Agency of Transportation, written \ncommunication, November 30, 1995). The opening length of the structure parallel to the \nbridge face is 36.9 ft. The bridge is supported by vertical, concrete abutments with \nwingwalls. The channel is skewed approximately 35 degrees to the opening while the \nopening-skew-to-roadway is 30 degrees.
\nThe scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) \nalong the left and right banks upstream that extended through the bridge and along the \ndownstream banks. Additional details describing conditions at the site are included in the \nLevel II Summary and Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge is analyzed since it has the potential of being the worst-case scour scenario. Total \nscour at a highway crossing is comprised of three components: 1) long-term streambed \ndegradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow \narea at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.
\nContraction scour for all modelled flows ranged from 0.0 to 1.1 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 6.5 to \n14.9 ft. The worst-case abutment scour occurred at the incipient roadway-overtopping \ndischarge. Additional information on scour depths and depths to armoring are included in \nthe section titled “Scour Results”. Scoured-streambed elevations, based on the calculated \nscour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the \nbridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of \nerosive material and a homogeneous particle-size distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97664","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Burns, R.L., and Degnan, J.R., 1997, Level II scour analysis for Bridge 33 (HUNTTH00220033) on Town Highway 22, crossing Brush Brook, Huntington, Vermont: U.S. Geological Survey Open-File Report 97-664, iv, 51 p., https://doi.org/10.3133/ofr97664.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176151,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97664.GIF"},{"id":279694,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0664/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Huntington","otherGeospatial":"Brush Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b19e4b07f02db6a75fa","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240584,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Degnan, James R. 0000-0002-5665-9010 jrdegnan@usgs.gov","orcid":"https://orcid.org/0000-0002-5665-9010","contributorId":498,"corporation":false,"usgs":true,"family":"Degnan","given":"James","email":"jrdegnan@usgs.gov","middleInitial":"R.","affiliations":[{"id":405,"text":"NH/VT office of New England Water Science Center","active":true,"usgs":true},{"id":466,"text":"New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240583,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49983,"text":"ofr97663 - 1997 - Level II scour analysis for Bridge 34 (HUNTTH00210034) on Town Highway 21, crossing Brush Brook, Huntington, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T15:29:25","indexId":"ofr97663","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":"97-663","title":"Level II scour analysis for Bridge 34 (HUNTTH00210034) on Town Highway 21, crossing Brush Brook, Huntington, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nHUNTTH00210034 on Town Highway 21 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 6.23-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, Brush Brook has an incised, straight channel with a slope of \napproximately 0.03 ft/ft, an average channel top width of 43 ft and an average bank height \nof 4 ft. The channel bed material ranges from gravel to boulder with a median grain size \n(D50) of 90.0 mm (0.295 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.\n
\n
The Town Highway 21 crossing of Brush Brook is a 28-ft-long, one-lane bridge consisting \nof one 26-foot steel-beam span with a timber deck (Vermont Agency of Transportation, \nwritten communication November 30, 1995). The opening length of the structure parallel to \nthe bridge face is 25.4 ft. The bridge is supported by vertical, concrete abutments with a \nwingwall on the upstream right. The channel is skewed approximately 5 degrees to the \nopening and the computed opening-skew-to-roadway is 5 degrees.
\nA tributary enters Brush Brook on the right bank immediately downstream of the bridge. \nAt the confluence, the left bank of Brush Brook is eroded and there is a small void under the \ndownstream end of the left abutment footing which is completely exposed. The right \nabutment footing is also exposed. The scour countermeasures at the site include type-2 \nstone fill (less than 36 inches diameter) along the upstream banks and in front of the right \nabutment and type-3 stone fill (less than 48 inches diameter) along the entire base length of \nthe upstream right wingwall and along the downstream right bank. 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 0.0 to 0.7 ft. The worst-case \ncontraction scour occurred at the incipient roadway-overtopping discharge, which was less \nthan the 100-year discharge. Abutment scour ranged from 6.9 to 10.9 ft. The worst-case \nabutment scour occurred at the 500-year discharge. Additional information on scour depths \nand depths to armoring are included in the section titled “Scour Results”. 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/ofr97663","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Burns, R.L., and Ivanoff, M.A., 1997, Level II scour analysis for Bridge 34 (HUNTTH00210034) on Town Highway 21, crossing Brush Brook, Huntington, Vermont: U.S. Geological Survey Open-File Report 97-663, iv, 53 p., https://doi.org/10.3133/ofr97663.","productDescription":"iv, 53 p.","numberOfPages":"58","costCenters":[],"links":[{"id":176150,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":279695,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0663/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":"4f4e4b17e4b07f02db6a653a","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240582,"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":240581,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49982,"text":"ofr97662 - 1997 - Level II scour analysis for Bridge 21 (MORETH00010021) on Town Highway 1, crossing Cox Brook, Moretown, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T15:39:53","indexId":"ofr97662","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":"97-662","title":"Level II scour analysis for Bridge 21 (MORETH00010021) on Town Highway 1, crossing Cox Brook, Moretown, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nMORETH00010021 on Town Highway 1 crossing Cox Brook, Moretown, 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 2.85-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is predominantly forested.
\nIn the study area, Cox Brook has an incised, sinuous channel with a slope of approximately \n0.02 ft/ft, an average channel top width of 23 ft and an average bank height of 4 ft. The \nchannel bed material ranges from gravel to cobble with a median grain size (D50) of 47.5 \nmm (0.156 ft). The geomorphic assessment at the time of the Level I and Level II site visit \non July 18, 1996, indicated that the reach was stable.
\nThe Town Highway 1 crossing of Cox Brook is a 29-ft-long, two-lane bridge consisting of \none 27-foot steel-beam span (Vermont Agency of Transportation, written communication, \nOctober 13, 1995). The opening length of the structure parallel to the bridge face is 24.8 ft. \nThe bridge is supported by vertical, concrete abutments with wingwalls. The channel is \nskewed approximately 60 degrees to the opening while the measured opening-skew-to-roadway is 40 degrees.
\nA scour hole 1.0 ft deeper than the mean thalweg depth was observed along the left \nabutment downstream during the Level I assessment. The only scour protection measure at \nthe site was type-2 stone fill (less than 36 inches diameter) along the left bank upstream. \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-year 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 0.2 to 0.5 ft. The worst-case \ncontraction scour occurred at the incipient roadway-overtopping discharge, which was less \nthan the 100-year discharge. Abutment scour ranged from 2.8 to 4.0 ft. The worst-case \nabutment scour occurred at the left abutment at the 100-year discharge and at the right \nabutment 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/ofr97662","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Striker, L.K., and Medalie, L., 1997, Level II scour analysis for Bridge 21 (MORETH00010021) on Town Highway 1, crossing Cox Brook, Moretown, Vermont: U.S. Geological Survey Open-File Report 97-662, iv, 51 p., https://doi.org/10.3133/ofr97662.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176149,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97662.GIF"},{"id":279696,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0662/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Moretown","otherGeospatial":"Cox Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,44.125 ], [ -72.75,44.25 ], [ -72.625,44.25 ], [ -72.625,44.125 ], [ -72.75,44.125 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a81ec","contributors":{"authors":[{"text":"Striker, Lora K.","contributorId":41481,"corporation":false,"usgs":true,"family":"Striker","given":"Lora","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":240580,"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":240579,"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":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":240577,"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":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":49978,"text":"ofr97653 - 1997 - Level II scour analysis for Bridge 25 (REDSTH00360025) on Town Highway 36, crossing the West Branch Deerfield River, Readsboro, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T16:16:53","indexId":"ofr97653","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":"97-653","title":"Level II scour analysis for Bridge 25 (REDSTH00360025) on Town Highway 36, crossing the West Branch Deerfield River, Readsboro, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nREDSTH00360025 on Town Highway 36 crossing the West Branch Deerfield River, \nReadsboro, 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 Green Mountain section of the New England physiographic province in \nsouth-central Vermont. The 14.5-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is pasture on the upstream right \nbank and forest on the upstream left bank. The surface cover on the downstream right and \nleft banks is primarily grass, shrubs and brush.
\nIn the study area, the West Branch Deerfield River has an incised, sinuous channel with a \nslope of approximately 0.02 ft/ft, an average channel top width of 65 ft and an average bank \nheight of 4 ft. The channel bed material ranges from gravel to boulders, with a median grain \nsize (D50) of 117 mm (0.383 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on August 1, 1996, indicated that the reach was stable.
\nThe Town Highway 36 crossing of the West Branch Deerfield River is a 59-ft-long, two-lane bridge consisting of one 57-foot concrete T-beam span (Vermont Agency of \nTransportation, written communication, September 28, 1995). The opening length of the \nstructure parallel to the bridge face is 54 ft. The bridge is supported by vertical, concrete \nabutments with wingwalls. The channel is skewed approximately 50 degrees to the opening \nwhile the opening-skew-to-roadway is 30 degrees.
\nDuring the Level I assessment, a scour hole approximately 2 ft deeper than the mean \nthalweg depth was observed along the upstream right wingwall and a scour hole \napproximately 1 ft deeper than the mean thalweg depth was observed along the downstream \nleft wingwall. The scour protection measure at the site was type-2 stone fill (less than 36 \ninches diameter) at the downstream end of the downstream left wingwall, at the upstream \nend of the upstream right wingwall, at the downstream end of the right abutment, along the \nentire base length of the downstream right wingwall, along the upstream right bank and \nalong the downstream left bank. A stone wall was noted along the upstream left 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). \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 0.6 ft. The worst-case \ncontraction scour occurred at the incipient-overtopping discharge. Abutment scour ranged \nfrom 15.1 to 16.3 ft along the left abutment and from 7.4 to 9.2 ft along the right abutment. \nThe worst-case abutment scour occurred at the incipient-overtopping and 500-year \ndischarges for the left abutment and at the 500-year discharge for the right abutment. \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 \ntables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. \nScour 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/ofr97653","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Flynn, R.H., and Burns, R.L., 1997, Level II scour analysis for Bridge 25 (REDSTH00360025) on Town Highway 36, crossing the West Branch Deerfield River, Readsboro, Vermont: U.S. Geological Survey Open-File Report 97-653, iv, 54 p., https://doi.org/10.3133/ofr97653.","productDescription":"iv, 54 p.","numberOfPages":"59","costCenters":[],"links":[{"id":175372,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97653.GIF"},{"id":279700,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0653/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Readsboro","otherGeospatial":"Deerfield River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -73.125,42.75 ], [ -73.125,42.875 ], [ -72.875,42.875 ], [ -72.875,42.75 ], [ -73.125,42.75 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a801d","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":240571,"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":240572,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49977,"text":"ofr97652 - 1997 - Level II scour analysis for Bridge 29 (HUNTTH00290029) on Town Highway 29, crossing Cobb Brook, Huntington, Vermont","interactions":[],"lastModifiedDate":"2013-12-18T10:13:05","indexId":"ofr97652","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":"97-652","title":"Level II scour analysis for Bridge 29 (HUNTTH00290029) on Town Highway 29, crossing Cobb Brook, Huntington, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nHUNTTH00290029 on Town Highway 29 crossing Cobb 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 \nnorthwestern Vermont. The 4.16-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is forest upstream and downstream \nof the bridge.
\nIn the study area, Cobb Brook has an incised, straight channel with a slope of approximately \n0.024 ft/ft, an average channel top width of 53 ft and an average bank height of 4 ft. The \nchannel bed material ranges from gravel to bedrock with a median grain size (D50) of 112.0 \nmm (0.367 ft). The geomorphic assessment at the time of the Level I and Level II site visit \non June 25, 1996, indicated that the reach was stable.
\nThe Town Highway 29 crossing of Cobb Brook is a 36-ft-long, one-lane bridge consisting \nof one 30-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, December 11, 1995) and a wooden deck. The opening length of the \nstructure parallel to the bridge face is 27 ft.The bridge is supported by vertical, concrete \nabutments. The channel is skewed approximately 25 degrees to the opening while the \nopening-skew-to-roadway was measured to be 20 degrees. VTAOT records indicate an \nopening-skew-to-roadway of zero degrees.
\nA scour hole 1.5 ft deeper than the mean thalweg depth was observed extending from 12 ft \nupstream of the upstream end of the left abutment to 10 ft under the bridge in the center of \nthe channel during the Level I assessment. Another scour hole approximately 1.2 ft deeper \nthan the mean thalweg depth was observed along the downstream end of the right abutment \nduring the Level I assessment. The scour protection measures at the site included type-2 \nstone fill (less than 36 inches diameter) along the upstream end of the right abutment and \ntype-3 stone fill (less than 48 inches diameter) along the upstream end of the upstream left \nretaining wall. Additional details describing conditions at the site are included in the Level \nII 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 was computed to be zero ft. Abutment scour \nranged from 9.9 to 12.5 ft along the left abutment and from 6.2 to 8.6 ft along the right \nabutment. 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/ofr97652","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Flynn, R.H., 1997, Level II scour analysis for Bridge 29 (HUNTTH00290029) on Town Highway 29, crossing Cobb Brook, Huntington, Vermont: U.S. Geological Survey Open-File Report 97-652, iv, 50 p., https://doi.org/10.3133/ofr97652.","productDescription":"iv, 50 p.","numberOfPages":"55","costCenters":[],"links":[{"id":176956,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97652.GIF"},{"id":279701,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0652/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Hungtington","otherGeospatial":"Cobb Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -73.0,44.25 ], [ -73.0,44.375 ], [ -72.875,44.375 ], [ -72.875,44.25 ], [ -73.0,44.25 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b19e4b07f02db6a7f0a","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":240570,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"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":49975,"text":"ofr97650 - 1997 - Level II scour analysis for Bridge 33 (CONCTH00580033) on Town Highway 58, crossing Miles Stream, Concord, Vermont","interactions":[],"lastModifiedDate":"2013-12-18T10:31:48","indexId":"ofr97650","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":"97-650","title":"Level II scour analysis for Bridge 33 (CONCTH00580033) on Town Highway 58, crossing Miles Stream, Concord, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nCONCTH00580033 on Town Highway 58 crossing Miles Stream, Concord, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.
\nThe site is in the New England Upland section of the New England physiographic province \nin northeastern Vermont. The 17.9-mi2\n drainage area is in a predominantly rural and \nforested basin. In the vicinity of the study site, the surface cover is pasture upstream of the \nbridge while the immediate banks have dense woody vegetation. Downstream of the \nbridge, the right bank is forested and the left bank has shrubs and brush.
\nIn the study area, Miles Stream has an incised, sinuous channel with a slope of \napproximately 0.01 ft/ft, an average channel top width of 91 ft and an average bank height \nof 7 ft. The channel bed material ranges from gravel to boulder with a median grain size \n(D50) of 61.6 mm (0.188 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on August 15, 1995, indicated that the reach was stable.
\nThe Town Highway 58 crossing of Miles Stream is a 44-ft-long, two-lane bridge consisting \nof one 39-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 37.4 ft. The bridge is supported by vertical, concrete abutments with stone fill in \nfront creating spillthrough embankments. The channel is skewed approximately 20 degrees \nto the opening while the opening-skew-to-roadway is zero degrees.
\nThe only scour countermeasure at the site was type-3 stone fill (less than 48 inches \ndiameter) along the left and right banks upstream, in front of the abutments forming spill \nthrough embankments, and extending along the banks downstream. 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 0.0 to 1.8 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 4.0 to \n9.7 ft. The worst-case abutment scour occurred at the 500-year discharge for the right \nabutment and at the incipient roadway-overtopping discharge for the left abutment. \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/ofr97650","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Burns, R.L., 1997, Level II scour analysis for Bridge 33 (CONCTH00580033) on Town Highway 58, crossing Miles Stream, Concord, Vermont: U.S. Geological Survey Open-File Report 97-650, iv, 51 p., https://doi.org/10.3133/ofr97650.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":175841,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97650.GIF"},{"id":279703,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0650/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Concord","otherGeospatial":"Miles Stream","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a6528","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240568,"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":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":49971,"text":"ofr97646 - 1997 - Level II scour analysis for Bridge 2 (RYEGTH00020002) on Town Highway 2, crossing the Wells River, Ryegate, Vermont","interactions":[],"lastModifiedDate":"2013-12-18T11:50:48","indexId":"ofr97646","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":"97-646","title":"Level II scour analysis for Bridge 2 (RYEGTH00020002) on Town Highway 2, crossing the Wells River, Ryegate, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nRYEGTH00020002 on Town Highway 2 crossing the Wells River, Ryegate, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.
\nThe site is in the New England Upland section of the New England physiographic province \nin east-central Vermont. The 75.7-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover consists of cut grass, trees, and \nbrush on the flood plains while the immediate banks have dense woody vegetation.
\nIn the study area, the Wells River has an incised, sinuous channel with a slope of \napproximately 0.006 ft/ft, an average channel top width of 110 ft and an average bank \nheight of 12 ft. The channel bed material ranges from sand to boulder with a median grain \nsize (D50) of 82.3 mm (0.270 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on August 24, 1995, indicated that the reach was laterally unstable with \nmoderate fluvial erosion and meandering downstream of the bridge.
\nThe Town Highway 2 crossing of the Wells River is a 79-ft-long, two-lane bridge \nconsisting of one 75-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, March 27, 1995). The opening length of the structure parallel to the bridge \nface is 75.1 ft. The bridge is supported by vertical, concrete abutments, the left has a spill-through embankment, with wingwalls. The channel is not skewed to the opening and the \nopening-skew-to-roadway is zero degrees.
\nA scour hole 3 ft deeper than the mean thalweg depth was observed in the channel from \nupstream and through the bridge during the Level I assessment. The scour protection \ncounter-measures at the site included type-4 stone fill (less than 60 inches diameter) along \nthe base of the left abutment forming a spill-through embankment. There was also type-2 \nstone fill (less than 36 inches diameter) along the entire base length of the upstream right \nwingwall, the upstream right bank and downstream left bank. There was a stone wall along \nthe upstream left bank extending 130 ft from the bridge. In addition there was type-1 stone \nfill (less than 12 inches diameter) along the downstream right bank. 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. Total scour at a highway crossing is comprised of \nthree components: 1) long-term streambed degradation; 2) contraction scour (due to \naccelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused \nby accelerated flow around piers and abutments). Total scour is the sum of the three \ncomponents. Equations are available to compute depths for contraction and local scour and \na summary of the results of these computations follows.
\nContraction scour for all modelled flows was zero. Abutment scour ranged from 7.1 to 11.4 \nft. 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/ofr97646","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., 1997, Level II scour analysis for Bridge 2 (RYEGTH00020002) on Town Highway 2, crossing the Wells River, Ryegate, Vermont: U.S. Geological Survey Open-File Report 97-646, iv, 50 p., https://doi.org/10.3133/ofr97646.","productDescription":"iv, 50 p.","numberOfPages":"55","costCenters":[],"links":[{"id":175737,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97646.GIF"},{"id":279707,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0646/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Ryegate","otherGeospatial":"Wells River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.25,44.125 ], [ -72.25,44.25 ], [ -72.125,44.25 ], [ -72.125,44.125 ], [ -72.25,44.125 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a81c7","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240562,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":49970,"text":"ofr97632 - 1997 - Level II scour analysis for Bridge 7 (WALDTH00020007) on Town Highway 2, crossing Coles Brook, Walden, Vermont","interactions":[],"lastModifiedDate":"2013-12-18T12:01:13","indexId":"ofr97632","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":"97-632","title":"Level II scour analysis for Bridge 7 (WALDTH00020007) on Town Highway 2, crossing Coles Brook, Walden, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nWALDTH00020007 on Town Highway 2 crossing Coles Brook, Walden, Vermont (figures \n1–8). Coles Brook is also referred to as Joes Brook. A Level II study is a basic engineering \nanalysis of the site, including a quantitative analysis of stream stability and scour (U.S. \nDepartment of Transportation, 1993). Results of a Level I scour investigation also are \nincluded in Appendix E of this report. A Level I investigation provides a qualitative \ngeomorphic characterization of the study site. Information on the bridge, gleaned from \nVermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level \nI 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 north-eastern Vermont. The 12.8-mi2\n drainage area is in a predominantly rural and \nforested basin. In the vicinity of the study site, the surface cover is predominantly shrub and \nbrushland.
\nIn the study area, Coles Brook has a sinuous channel with a slope of approximately 0.005 ft/\nft, an average channel top width of 37 ft and an average bank height of 4 ft. The channel bed \nmaterial ranges from sand to cobble with a median grain size (D50) of 32.9 mm (0.108 ft). \nThe geomorphic assessment at the time of the Level I and Level II site visit on August 9, \n1995, indicated that the reach was laterally unstable due to cut-banks, point bars, and loose \nunconsolidated bed material.
\nThe Town Highway 2 crossing of Coles Brook is a 74-ft-long, two-lane bridge consisting of \none 71-foot steel-beam span (Vermont Agency of Transportation, written communication, \nApril 5, 1995). The opening length of the structure parallel to the bridge face is 69.3 ft. The \nbridge is supported by spill-through abutments. The channel is skewed approximately 35 \ndegrees to the opening while the measured opening-skew-to-roadway is 15 degrees.
\nA scour hole 1.5 ft deeper than the mean thalweg depth was observed from 60 ft. to 100 ft. \ndownstream during the Level I assessment. Scour protection measures at the site include: \ntype-1 stone fill (less than 12 inches diameter) along the right bank upstream, at the \ndownstream end of the downstream left wingwall and downstream right wingwall; and \ntype-2 stone fill (less than 36 inches diameter) along the left bank upstream, at the upstream \nend of the upstream right wingwall, and along the entire base of the left and right \nabutments. Additional details describing conditions at the site are included in the Level II \nSummary and Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). \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 0.8 ft. The worst-case \ncontraction scour occurred at the incipient roadway-overtopping discharge. Abutment scour \nranged from 5.7 to 12.9 ft. The worst-case 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/ofr97632","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Striker, L.K., and Medalie, L., 1997, Level II scour analysis for Bridge 7 (WALDTH00020007) on Town Highway 2, crossing Coles Brook, Walden, Vermont: U.S. Geological Survey Open-File Report 97-632, iv, 51 p., https://doi.org/10.3133/ofr97632.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":175736,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97632.GIF"},{"id":279708,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0632/report.pdf"}],"scale":"25000","country":"United States","state":"Vermont","city":"Walden","otherGeospatial":"Coles Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.25,44.375 ], [ -72.25,44.5 ], [ -72.0,44.5 ], [ -72.0,44.375 ], [ -72.25,44.375 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b16e4b07f02db6a571f","contributors":{"authors":[{"text":"Striker, Lora K.","contributorId":41481,"corporation":false,"usgs":true,"family":"Striker","given":"Lora","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":240561,"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":240560,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49969,"text":"ofr97629 - 1997 - Level II scour analysis for Bridge 39 (LOWETH00080039) on Town Highway 8, crossing Potter Brook, Lowell, Vermont","interactions":[],"lastModifiedDate":"2013-12-18T12:42:52","indexId":"ofr97629","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":"97-629","title":"Level II scour analysis for Bridge 39 (LOWETH00080039) on Town Highway 8, crossing Potter Brook, Lowell, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nLOWETH00080039 on Town Highway 8 crossing Potter Brook, Lowell, 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 \nnorth-central Vermont. The 4.69-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover consists of shrub and brushland, \nexcept for the left overbank upstream which is forest.
\nIn the study area, Potter Brook has a sinuous channel with a slope of approximately 0.004 \nft/ft, an average channel top width of 34 feet and an average bank height of 3 ft. The \npredominant channel bed materials are gravel and sand with a median grain size (D50) of \n18.7 mm (0.0613 ft). The geomorphic assessment at the time of the Level I and Level II site \nvisit on June 15, 1995, indicated that the reach was laterally unstable. This assessment of \nthe reach was primarily due to the meandering of the channel with cut-banks and narrow \npoint bars and the fine bank and bed material near the site.
\nThe Town Highway 8 crossing of Potter Brook is a 23-ft-long, one-lane bridge consisting of \none 21-foot steel-beam span (Vermont Agency of Transportation, written communication, \nMarch 7, 1995). The bridge is supported by vertical, concrete abutments with wingwalls. \nThe channel is skewed approximately 20 degrees to the opening while the opening-skew-toroadway is zero degrees.\nA scour hole 2.0 feet deeper than the mean thalweg depth was observed along the left \nabutment during the Level I assessment. There were no scour protection measures evident \nat the site. Additional details describing conditions at the site are included in the Level II \nSummary and Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). \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 0.3 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 1.8 to \n5.5 feet. The worst-case abutment scour occurred at the 100-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/ofr97629","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 39 (LOWETH00080039) on Town Highway 8, crossing Potter Brook, Lowell, Vermont: U.S. Geological Survey Open-File Report 97-629, iv, 50 p., https://doi.org/10.3133/ofr97629.","productDescription":"iv, 50 p.","numberOfPages":"55","costCenters":[],"links":[{"id":175735,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97629.GIF"},{"id":279709,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0629/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Lowell","otherGeospatial":"Potter 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":"4f4e4b17e4b07f02db6a6257","contributors":{"authors":[{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240559,"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":240558,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49968,"text":"ofr97628 - 1997 - Level II scour analysis for Bridge 31 (BRISTH00030031) on Town Highway 3, crossing the New Haven River, Bristol, Vermont","interactions":[],"lastModifiedDate":"2013-12-18T12:51:55","indexId":"ofr97628","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":"97-628","title":"Level II scour analysis for Bridge 31 (BRISTH00030031) on Town Highway 3, crossing the New Haven River, Bristol, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nBRISTH00030031 on Town Highway 3 crossing the New Haven River, Bristol, 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 \nwest-central, western Vermont. The 69.1-mi2\n drainage area is in a predominantly rural and \nforested basin. In the vicinity of the study site, the surface cover is forest except on the \ndownstream left overbank which has closely spaced houses with lawns.
\nIn the study area, the New Haven River has an incised, sinuous channel with a slope of \napproximately 0.01 ft/ft, an average channel top width of 136 ft and an average bank height \nof 13 ft. The channel bed material ranges from gravel to boulder with a median grain size \n(D50) of 233 mm (0.765 ft). The geomorphic assessment at the time of the Level I and Level \nII site visit on June 20, 1996, indicated that the reach was stable.
\nThe Town Highway 3 crossing of the New Haven River is a 105-ft-long, two-lane bridge \nconsisting of a 101-ft-long pony truss span (Vermont Agency of Transportation, written \ncommunication, November 30, 1995). The opening length of the structure parallel to the \nbridge face is 98 ft. The bridge is supported by vertical, concrete abutments with wingwalls. \nThe channel is skewed approximately 60 degrees to the opening, with no opening-skew-to-roadway.
\nA local scour hole 3 ft deeper than the mean thalweg depth was observed near the exit cross \nsection during the Level I assessment. Scour countermeasures included a stone wall on the \nupstream right bank, type-3 stone fill (less than 48 inches diameter) on the upstream and \ndownstream left banks, and type-2 stone fill (less than 36 inches diameter) on the \ndownstream end of the right abutment and on the downstream right bank. 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). \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 for any of the modelled flows. Abutment scour ranged from \n12.7 to 16.4 ft. The worst-case abutment scour occurred at the 500-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/ofr97628","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Degnan, J.R., 1997, Level II scour analysis for Bridge 31 (BRISTH00030031) on Town Highway 3, crossing the New Haven River, Bristol, Vermont: U.S. Geological Survey Open-File Report 97-628, iv, 48 p., https://doi.org/10.3133/ofr97628.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":175734,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97628.GIF"},{"id":279710,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0628/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Bristol","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":"4f4e4b19e4b07f02db6a7dcd","contributors":{"authors":[{"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":240557,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"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":49966,"text":"ofr97626 - 1997 - Level II scour analysis for Bridge 18 (GROTTH00480018) on Town Highway 48, crossing the Wells River Groton, Vermont","interactions":[],"lastModifiedDate":"2013-12-18T13:12:37","indexId":"ofr97626","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":"97-626","title":"Level II scour analysis for Bridge 18 (GROTTH00480018) on Town Highway 48, crossing the Wells River Groton, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nGROTTH00480018 on Town Highway 48 crossing the Wells River, Groton, 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 53.6-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is pasture on the right bank \nupstream and the left bank downstream while the surface cover is shrub and brushland \nalong the left bank upstream and the right bank downstream. The immediate banks are \nvegetated with brush and scattered trees.
\nIn the study area, the Wells River has an incised, straight channel with a slope of \napproximately 0.003 ft/ft, an average channel top width of 69 ft and an average bank height \nof 7 ft. The channel bed material ranges from sand to cobble with a median grain size (D50) \nof 66.7 mm (0.219 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 stable.
\nThe Town Highway 48 crossing of the Wells River is a 38-ft-long, one-lane bridge \nconsisting of one 36-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 33.7 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The \nchannel is skewed approximately 0 degrees to the opening and the opening-skew-toroadway is also 0 degrees.
\nLocal scour 3.25 ft deeper than the mean thalweg depth was observed underneath the bridge \nalong the left and right abutments during the Level I assessment. In addition, a scour hole \nextends from 90 ft US to 50 ft DS for a total length of 115 ft with an average scour depth of \n2.0 ft. The only scour protection measure at the site was type-2 stone fill (less than 36 \ninches diameter) along the left bank upstream, along the entire base length of the \ndownstream right wingwall, and along the left and right banks downstream; and type-1 \nstone fill (less than 12 inches diameter) along the entire base length of the upstream left \nwingwall. Additional details describing conditions at the site are included in the Level II \nSummary and Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge 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 was 0.0 ft. Abutment scour ranged from 2.0 to 2.3 \nft at the left abutment and 8.8 to 14.6 ft at the right abutment. The worst-case abutment \nscour occurred at the 500-year discharge at the right abutment. Additional information on \nscour depths and depths to armoring are included in the section titled “Scour Results”. \nScoured-streambed elevations, based on the calculated scour depths, are presented in tables \n1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour \ndepths were calculated assuming an infinite depth of erosive material and a homogeneous \nparticle-size distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97626","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Striker, L.K., and Medalie, L., 1997, Level II scour analysis for Bridge 18 (GROTTH00480018) on Town Highway 48, crossing the Wells River Groton, Vermont: U.S. Geological Survey Open-File Report 97-626, iv, 51 p., https://doi.org/10.3133/ofr97626.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":175732,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97626.GIF"},{"id":279712,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0626/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Groton","otherGeospatial":"Wells River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.25,44.125 ], [ -72.25,44.25 ], [ -72.125,44.25 ], [ -72.125,44.125 ], [ -72.25,44.125 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8308","contributors":{"authors":[{"text":"Striker, Lora K.","contributorId":41481,"corporation":false,"usgs":true,"family":"Striker","given":"Lora","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":240555,"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":240554,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49965,"text":"ofr97594 - 1997 - Level II scour analysis for Bridge 40 (ANDOVT00110040) on State Route 11, crossing Lyman Brook, Andover, Vermont","interactions":[],"lastModifiedDate":"2013-12-18T13:35:28","indexId":"ofr97594","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":"97-594","title":"Level II scour analysis for Bridge 40 (ANDOVT00110040) on State Route 11, crossing Lyman Brook, Andover, Vermont","docAbstract":"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":49964,"text":"ofr97593 - 1997 - Level II scour analysis for Bridge 13 (SHARTH00040013) on Town Highway 4, crossing Broad Brook, Sharon, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T16:06:05","indexId":"ofr97593","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":"97-593","title":"Level II scour analysis for Bridge 13 (SHARTH00040013) on Town Highway 4, crossing Broad Brook, Sharon, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure SHARTH00040013 on Town Highway 4 crossing Broad Brook, Sharon, 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 New England Upland section of the New England physiographic province in central Vermont. The 16.6-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is brushland on the downstream left overbank and row crops on the right overbank, while the immediate banks have dense woody vegetation. Upstream of the bridge, the overbanks are forested.
In the study area, Broad Brook has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 69 ft and an average bank height of 5 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) of 112 mm (0.369 ft). The geomorphic assessment at the time of the Level I site visit on April 11, 1995 and Level II site visit on July 23, 1996, indicated that the reach was stable.
The Town Highway 4 crossing of Broad Brook is a 34-ft-long, two-lane bridge consisting of one 31-foot concrete tee beam span (Vermont Agency of Transportation, written communication, March 23, 1995). The opening length of the structure parallel to the bridge face is 30.1 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 10 degrees to the opening while the opening-skew-to-roadway is 15 degrees.
A scour hole 2.0 ft deeper than the mean thalweg depth was observed along the upstream end of the right abutment. At the downstream end of the left abutment, a 1.0 foot scour hole was observed . Scour countermeasures at the site include type-2 stone fill (less than 3 feet diameter) at each road embankment. 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 0.7 to 1.8 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 5.6 to 9.4 ft. The worst case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 19.0 to 19.8 ft. The worst-case right abutment scour occurred at the incipient-overtopping discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.
It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97593","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., and Weber, M.A., 1997, Level II scour analysis for Bridge 13 (SHARTH00040013) on Town Highway 4, crossing Broad Brook, Sharon, Vermont: U.S. Geological Survey Open-File Report 97-593, iv, 52 p., https://doi.org/10.3133/ofr97593.","productDescription":"iv, 52 p.","numberOfPages":"57","costCenters":[],"links":[{"id":175730,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97593.GIF"},{"id":279714,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0593/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Sharon","otherGeospatial":"Broad 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":"4f4e4b1ae4b07f02db6a8330","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":240550,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Weber, Matthew A.","contributorId":41483,"corporation":false,"usgs":true,"family":"Weber","given":"Matthew","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240551,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49963,"text":"ofr97592 - 1997 - Level II scour analysis for Bridge 48 (FFIETH00300048) on Town Highway 30, crossing Wanzer Brook, Fairfield, Vermont","interactions":[],"lastModifiedDate":"2013-12-18T14:02:55","indexId":"ofr97592","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":"97-592","title":"Level II scour analysis for Bridge 48 (FFIETH00300048) on Town Highway 30, crossing Wanzer Brook, Fairfield, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nFFIETH00300048 on Town Highway 30 crossing Wanzer Brook, 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 \nnorthwestern Vermont. The 6.78-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover upstream of the bridge and on the \ndownstream right bank is primarily pasture. The downstream left bank is forested.
\nIn the study area, Wanzer Brook has an incised, straight channel with a slope of \napproximately 0.03 ft/ft, an average channel top width of 65 ft and an average bank height \nof 5 ft. The channel bed material is cobble with a median grain size (D50) of 111 mm (0.364 \nft). The geomorphic assessment at the time of the Level I and Level II site visit on July 11, \n1995, indicated that the reach was stable.
\nThe Town Highway 30 crossing of Wanzer Brook is a 31-ft-long, two-lane bridge \nconsisting of one 28-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 26 ft.The bridge is supported by vertical stone wall abutments with concrete caps and \n“kneewall” footings. The channel is skewed approximately 25 degrees to the opening while \nthe measured opening-skew-to-roadway is 20 degrees.
\nA scour hole 1.5 ft deeper than the mean thalweg depth was observed along the downstream \nleft retaining wall (extended concrete footing) during the Level I assessment. It was also \nobserved that the right abutment is undermined with a scour depth of 0.5 ft. The scour \nprotection at the site was limited to four large boulders (type-4, less than 60 inches \ndiameter) along the downstream right retaining wall. The channel under the bridge is a \n“corduroy” log mat floor composed of 13 logs which are parallel to the bridge face and \nextend from 5 ft under the bridge to the downstream bridge face. The most downstream log \nis approximately 0.3 to 0.4 ft higher than the other logs and controls flow at lower flows. \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). \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 0.3 to 0.6 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 14.1 to \n16.0 ft at the left abutment and from 6.8 to 7.6 ft at the right abutment. The worst-case \nabutment scour occurred at the 500-year discharge. Additional information on scour depths \nand depths to armoring are included in the section titled “Scour Results”. 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/ofr97592","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Flynn, R.H., and Boehmler, E.M., 1997, Level II scour analysis for Bridge 48 (FFIETH00300048) on Town Highway 30, crossing Wanzer Brook, Fairfield, Vermont: U.S. Geological Survey Open-File Report 97-592, iv, 48 p., https://doi.org/10.3133/ofr97592.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":175622,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97592.GIF"},{"id":279715,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0592/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Fairfield","otherGeospatial":"Wanzer Brook","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":"4f4e4b17e4b07f02db6a606a","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":240548,"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":240549,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49962,"text":"ofr97591 - 1997 - Level II scour analysis for Bridge 22 (JAY-TH00400022) on Town Highway 40, crossing Jay Branch, Jay, Vermont","interactions":[],"lastModifiedDate":"2013-12-18T14:14:08","indexId":"ofr97591","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":"97-591","title":"Level II scour analysis for Bridge 22 (JAY-TH00400022) on Town Highway 40, crossing Jay Branch, Jay, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nJAY-TH00400022 on Town Highway 40 crossing Jay Tributary, Jay, Vermont (figures 1–\n8). 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 \nnorthern Vermont. The 2.15-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is primarily pasture on the upstream \nand downstream left overbank while the immediate banks have dense woody vegetation. \nThe downstream right overbank of the bridge is forested.
\nIn the study area, Jay Branch Tributary has an incised, sinuous channel with a slope of \napproximately 0.02 ft/ft, an average channel top width of 26 ft and an average bank height \nof 3 ft. The channel bed material ranges from gravel to cobble with a median grain size \n(D50) of 40.5 mm (0.133 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on June 7, 1995, indicated that the reach was stable.
\nThe Town Highway 40 crossing of Jay Branch Tributary is a 27-ft-long, two-lane bridge \nconsisting of one 25-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, March 6, 1995). The opening length of the structure parallel to the bridge \nface is 23.5 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The \nchannel skew and the opening-skew-to-roadway are zero degrees.
\nThe scour counter-measures at the site included type-2 stone fill (less than 36 inches \ndiameter) at the upstream end of the left and right abutments, at the upstream right \nwingwall, and at the downstream left wingwall. There was also type-3 stone fill (less than \n48 inches diameter) at the upstream left and downstream 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). \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 0.7 to 1.1 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Left abutment scour ranged from 4.6 \nto 4.9 ft. The worst-case left abutment scour occurred at the 100-year discharge. Right \nabutment scour ranged from 4.0 to 5.0 ft. The worst-case right abutment scour occurred at \nthe 500-year discharge. Additional information on scour depths and depths to armoring are \nincluded in the section titled “Scour Results”. Scoured-streambed elevations, based on the \ncalculated scour depths, are presented in tables 1 and 2. A cross-section of the scour \ncomputed at the bridge is presented in figure 8. Scour depths were calculated assuming an \ninfinite 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/ofr97591","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., and Song, D.L., 1997, Level II scour analysis for Bridge 22 (JAY-TH00400022) on Town Highway 40, crossing Jay Branch, Jay, Vermont: U.S. Geological Survey Open-File Report 97-591, iv, 48 p., https://doi.org/10.3133/ofr97591.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":175621,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97591.GIF"},{"id":279716,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0591/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Jay","otherGeospatial":"Jay Branch Tributary","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.5,44.875 ], [ -72.5,45.0 ], [ -72.375,45.0 ], [ -72.375,44.875 ], [ -72.5,44.875 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a816f","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240546,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Song, Donald L.","contributorId":107335,"corporation":false,"usgs":true,"family":"Song","given":"Donald","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240547,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ]}