This report provides the results of a detailed Level II analysis of scour potential at structure \nNEWFVT00300013 on State Route 30 crossing Smith Brook, Newfane, 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 New England Upland section of the New England physiographic province \nin southeastern Vermont. The 9.38-mi2\n drainage area is in a predominantly rural and \nforested basin. In the vicinity of the study site, the surface cover is grass and shrubs except \nfor the upstream right bank which is forested.
\nIn the study area, Smith Brook has an incised, sinuous channel with a slope of \napproximately 0.01 ft/ft, an average channel top width of 53 ft and an average bank height \nof 5 ft. The channel bed material is predominantly cobbles with a median grain size (D50) of \n79.5 mm (0.261 ft). The geomorphic assessment at the time of the Level I and Level II site \nvisit on August 20, 1996, indicated that the reach was stable.
\nThe State Route 30 crossing of Smith Brook is a 69-ft-long, two-lane bridge consisting of \none 66-foot steel-beam span (Vermont Agency of Transportation, written communication, \nMarch 30, 1995). The bridge is supported by vertical, concrete abutments with wingwalls. \nThe channel is skewed approximately 45 degrees to the opening while the opening-skew-to-\nroadway is 55 degrees.
\nThe scour protection measures at the site were type-1 stone fill (less than 12 inches \ndiameter) along the upstream right bank. There was also type-2 stone fill (less than 36 \ninches diameter) along the upstream left bank. A stone wall extends to 72 feet upstream \nfrom the end of the upstream left wingwall. There is another stone wall along the upstream \nright bank. 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 500-year discharge. Abutment scour ranged from 14.4 to \n18.2 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/ofr97218","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., and Medalie, L., 1997, Level II scour analysis for Bridge 30 (NEWFVT00300013) on Vermont Highway 30, crossing Smith Brook, Newfane, Vermont: U.S. Geological Survey Open-File Report 97-218, iv, 48 p., https://doi.org/10.3133/ofr97218.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":169645,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97218.GIF"},{"id":279778,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0218/report.pdf"}],"scale":"25000","country":"United States","state":"Vermont","city":"Newfane","otherGeospatial":"Smith 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":"4f4e4b19e4b07f02db6a7eb9","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240458,"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":240457,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49908,"text":"ofr97225 - 1997 - Level II scour analysis for Bridge 27 (ANDOTH00290027) on Town Highway 29, crossing Middle Branch Williams River, Andover, Vermont","interactions":[],"lastModifiedDate":"2014-01-05T13:56:45","indexId":"ofr97225","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":"97-225","title":"Level II scour analysis for Bridge 27 (ANDOTH00290027) on Town Highway 29, crossing Middle Branch Williams River, Andover, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nANDOTH00290027 on Town Highway 29 crossing the Middle Branch Williams River, \nAndover, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, \nincluding a quantitative analysis of stream stability and scour (U.S. Department of \nTransportation, 1993). Results of a Level I scour investigation also are included in \nAppendix E of this report. A Level I investigation provides a qualitative geomorphic \ncharacterization of the study site. Information on the bridge, gleaned from Vermont Agency \nof Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II \nanalyses and is found in Appendix D.
\nThe site is in the Green Mountain section of the New England physiographic province in \ncentral Vermont. The 12.7-mi2\n drainage area is in a predominantly rural and forested basin. \nIn the vicinity of the study site, the surface cover is pasture on the left bank upstream of the \nbridge while the immediate bank has woody vegetation. The surface cover on the upstream \nright bank is forest. Downstream of the bridge the left bank is pasture and the right bank \nhas woody vegetation.
\nIn the study area, the Middle Branch Williams River has an incised, straight channel with a \nslope of approximately 0.009 ft/ft, an average channel top width of 63 ft and an average \nbank height of 5 ft. The channel bed material ranges from sand to cobble with a median \ngrain size (D50) of 64.7 mm (0.212 ft). The geomorphic assessment at the time of the Level \nI and Level II site visit on September 10, 1996, indicated that the reach was stable.
\nThe Town Highway 29 crossing of the Middle Branch Williams River is a 34-ft-long, two-\nlane bridge consisting of one 32-foot steel-beam span (Vermont Agency of Transportation, \nwritten communication, April 5, 1995). The bridge is supported by vertical, concrete \nabutments with wingwalls. The channel is skewed approximately 25 degrees to the opening \nwhile the opening-skew-to-roadway is 0 degrees.
\nA scour hole 1.5 ft deeper than the mean thalweg depth was observed along the left \nabutment during the Level I assessment. Scour protection measures at the site include type-\n2 stone fill (less than 36 inches diameter) along the upstream right bank and downstream \nleft bank and around the upstream left and right wingwalls. Type- 3 stone fill (less than 48 \ninches diameter) is located along the base of the left abutment in the scour hole, at the end \nof the downstream left wingwall and along the upstream left 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.
\nContraction scour for all modelled flows ranged from 0.4 to 0.9 ft. The worst-case \ncontraction scour occurred at the incipient-overtopping discharge and the 100-year \ndischarge. Abutment scour ranged from 10.7 to 13.6 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/ofr97225","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 27 (ANDOTH00290027) on Town Highway 29, crossing Middle Branch Williams River, Andover, Vermont: U.S. Geological Survey Open-File Report 97-225, iv, 50 p., https://doi.org/10.3133/ofr97225.","productDescription":"iv, 50 p.","numberOfPages":"55","costCenters":[],"links":[{"id":169646,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97225.GIF"},{"id":279775,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0225/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Andover","otherGeospatial":"Middle Branch Williams River","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":"4f4e4b1ae4b07f02db6a7ffe","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240460,"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":240459,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49909,"text":"ofr97226 - 1997 - Level II scour analysis for Bridge 12 (HUNTTH00010012) on Town Highway 001, crossing Brush Brook, Huntington, Vermont","interactions":[],"lastModifiedDate":"2014-01-06T11:07:06","indexId":"ofr97226","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":"97-226","title":"Level II scour analysis for Bridge 12 (HUNTTH00010012) on Town Highway 001, crossing Brush Brook, Huntington, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nHUNTTH00010012 on Town Highway 1 crossing Brush Brook, Huntington, Vermont \n(figures 1–9). 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.
\nIn August 1976, Hurricane Belle caused flooding at this site which resulted in road and \nbridge damage (figures 7-8). This was approximately a 25-year flood event based on flood-\nfrequency data contained in the Flood Insurance Study for the Town of Huntington (U.S. \nDepartment of Housing and Urban Development, 1978).
\nThe site is in the Green Mountain section of the New England physiographic province in \ncentral Vermont. The 9.19-mi2\n drainage area is in a predominantly rural and forested basin. \nIn the vicinity of the study site, the surface cover is pasture while the immediate banks have \nsome woody vegetation.
\nIn the study area, the Brush Brook has a sinuous channel with a slope of approximately 0.02 \nft/ft, an average channel top width of 62 ft and an average bank height of 5 ft. The channel \nbed material ranges from gravel to cobble with a median grain size (D50) of 100.0 mm \n(0.328 ft). The geomorphic assessment at the time of the Level I and Level II site visit on \nJune 25, 1996, indicated that the reach was stable.
\nThe Town Highway 1 crossing of Brush Brook is a 64-ft-long, two-lane bridge consisting of \none 62-foot steel-stringer span (Vermont Agency of Transportation, written \ncommunication, November 30, 1995). The bridge is supported by vertical, concrete \nabutments with wingwalls. The channel is skewed approximately 10 degrees to the opening \nwhile the opening-skew-to-roadway is 6 degrees.
\nChannel scour 2.2 ft deeper than the mean thalweg depth was observed along the upstream \nright bank and along the base of the spill-through protection for the right abutment during \nthe Level I assessment. Scour protection measured at the site was type-2 stone fill (less \nthan 36 inches diameter) along the upstream left and right banks and in front of all four \nwingwalls. In front of the abutments, there was type-3 stone fill (less than 48 inches \ndiameter) forming a spill-through slope. 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.
\nThere was no computed contraction scour for any modelled flow. Abutment scour ranged \nfrom 1.4 to 2.8 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 9. 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/ofr97226","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 12 (HUNTTH00010012) on Town Highway 001, crossing Brush Brook, Huntington, Vermont: U.S. Geological Survey Open-File Report 97-226, iv, 49 p., https://doi.org/10.3133/ofr97226.","productDescription":"iv, 49 p.","numberOfPages":"54","costCenters":[],"links":[{"id":169718,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97226.GIF"},{"id":279777,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0226/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\": [ [ [ -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":"4f4e4b1ae4b07f02db6a83b3","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240462,"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":240461,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49914,"text":"ofr97342 - 1997 - Level II scour analysis for Bridge 43 (CHESVT00110043) on State Highway 11, crossing the Middle Branch Williams River, Chester, Vermont","interactions":[],"lastModifiedDate":"2014-01-05T13:14:13","indexId":"ofr97342","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":"97-342","title":"Level II scour analysis for Bridge 43 (CHESVT00110043) on State Highway 11, crossing the Middle Branch Williams River, Chester, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nCHESVT00110043 on State Route 11 crossing the Middle Branch of the Williams River, \nChester, 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 principally in the Green Mountain section of the New England physiographic \nprovince in southeastern Vermont. The 13.7-mi2\n drainage area is in a predominantly rural \nand forested basin. In the vicinity of the study site, the surface cover is predominantly forest \nexcept for the area downstream and right of the bridge which is pasture.
\nIn the study area, the Middle Branch of the Williams River has a sinuous channel with a \nslope of approximately 0.01 ft/ft, an average channel top width of 77 ft and an average bank \nheight of 8 ft. The channel bed material ranges from gravel to boulder with a median grain \nsize (D50) of 76.6 mm (0.251 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on September 11, 1996, indicated that the reach was laterally unstable. \nLateral instability was evident from the several point bars and cut banks located through the \nstudy reach.
\nThe State Route 11 crossing of the Middle Branch of the Williams River is a\n76-ft-long, two-lane bridge consisting of two 37-foot concrete Tee-beam spans (Vermont \nAgency of Transportation, written communication, March 29, 1995). The bridge is \nsupported by vertical, concrete abutments with wingwalls. The channel is skewed \napproximately 35 degrees to the opening. The computed opening-skew-to-roadway was 30 \ndegrees but the historical records indicate this angle is 25 degrees.
\nScour protection measures at the site consist of type-1 stone fill (less than 12 inches \ndiameter) along the downstream banks and the upstream right wing wall. Type-2 (less than \n36 inches diameter) stone fill protection is noted on the upstream and downstream left \nwingwalls and upstream along the left bank. Additional details describing conditions at the \nsite are included in the Level II Summary and Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). \nTotal scour at a highway crossing is comprised of three components: 1) long-term \nstreambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction \nin flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.
\nContraction scour for all modelled flows ranged from 0.0 to 1.5 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 7.2 to \n10.7 ft. The worst-case abutment scour occurred at the 500-year discharge for the right \nabutment. Pier scour ranged from 7.3 to 8.6 ft. The worst-case pier scour occurred at the \n500-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/ofr97342","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Striker, L.K., and Burns, R.L., 1997, Level II scour analysis for Bridge 43 (CHESVT00110043) on State Highway 11, crossing the Middle Branch Williams River, Chester, Vermont: U.S. Geological Survey Open-File Report 97-342, iv, 50 p., https://doi.org/10.3133/ofr97342.","productDescription":"iv, 50 p.","numberOfPages":"55","costCenters":[],"links":[{"id":169723,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":279771,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0342/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Chester","otherGeospatial":"Williams River","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":"4f4e4b17e4b07f02db6a614c","contributors":{"authors":[{"text":"Striker, Lora K.","contributorId":41481,"corporation":false,"usgs":true,"family":"Striker","given":"Lora","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":240468,"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":240469,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49915,"text":"ofr97343 - 1997 - Level II scour analysis for Bridge 53 (WILMVT01000053) on State Route 100, crossing Cold Brook, Wilmington, Vermont","interactions":[],"lastModifiedDate":"2014-01-05T13:06:31","indexId":"ofr97343","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":"97-343","title":"Level II scour analysis for Bridge 53 (WILMVT01000053) on State Route 100, crossing Cold Brook, Wilmington, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nWILMVT01000053 on State Route 100 crossing Cold Brook, Wilmington, 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 \nsouth-central Vermont. The 8.38-mi2 drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover predominantly is pasture except for \nthe immediate channel banks, which are tree covered.
\nIn the study area, Cold Brook has a straight channel with a slope of approximately 0.04 ft/ft, \nan average channel top width of 63 feet and an average bank height of 9 feet. The channel is \nconstructed with stone fill completely covering both banks for 300 feet upstream of the site. \nThe predominant channel bed materials are gravel and cobbles with a median grain size \n(D50) of 66.2 mm (0.217 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on August 7, 1996, indicated that the reach was constructed.
\nThe State Route 100 crossing of Cold Brook is a 23-ft-long, two-lane bridge divided by a \nmedian strip consisting of one 20-foot concrete span (Vermont Agency of Transportation, \nwritten communication, November 1, 1995). The bridge is supported by vertical, concrete \nabutments with wingwalls. The channel is not skewed to the opening and the opening-skew-\nto-roadway also is zero degrees.
\nThe scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) \non the upstream banks, the upstream wingwalls, and the downstream left wingwall. \nAdditional details describing conditions at the site are included in the Level II Summary \nand Appendices D and E.
\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a \nhighway crossing is comprised of three components: 1) long-term streambed degradation; \n2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) \nand; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is \nthe sum of the three components. Equations are available to compute depths for contraction \nand local scour and a summary of the results of these computations follows.
\nContraction scour for all modelled flows ranged from 0.6 to 2.7 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 4.8 to \n10.9 ft. The worst-case abutment scour occurred at the left abutment for 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/ofr97343","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Boehmler, E.M., 1997, Level II scour analysis for Bridge 53 (WILMVT01000053) on State Route 100, crossing Cold Brook, Wilmington, Vermont: U.S. Geological Survey Open-File Report 97-343, iv, 49 p., https://doi.org/10.3133/ofr97343.","productDescription":"iv, 49 p.","numberOfPages":"54","costCenters":[],"links":[{"id":170176,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":279770,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0343/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Wilmington","otherGeospatial":"Cold 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":"4f4e4b17e4b07f02db6a5b46","contributors":{"authors":[{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240470,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":49917,"text":"ofr97345 - 1997 - Level II scour analysis for Bridge 11R (ROCKTH0001011R) on Town Highway 1 (VT 121 & FAS 125), crossing the Saxtons River, Rockingham, Vermont","interactions":[],"lastModifiedDate":"2014-01-05T12:42:26","indexId":"ofr97345","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":"97-345","title":"Level II scour analysis for Bridge 11R (ROCKTH0001011R) on Town Highway 1 (VT 121 & FAS 125), crossing the Saxtons River, Rockingham, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nROCKTH0001011R on Town Highway 1 crossing the Saxtons River, Rockingham, \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 southeastern Vermont. The 68.3-mi2\n drainage area is in a predominantly rural and \nforested basin. In the vicinity of the study site, the surface cover consists of houses, short \ngrass, and scattered trees except along the immediate river banks, which are tree covered.
\nIn the study area, the Saxtons River has a sinuous channel with a slope of approximately \n0.005 ft/ft, an average channel top width of 121 ft and an average bank height of 8 ft. The \npredominant channel bed materials are gravel and cobbles with a median grain size (D50) of \n109 mm (0.359 ft). The geomorphic assessment at the time of the Level I and Level II site \nvisit on September 3, 1996, indicated that the reach was laterally unstable. Lateral \ninstability was evident with respect to a cut-bank on the left bank upstream with slip failure \nof bank material. Furthermore, there is a wide point bar along the right bank upstream \nopposite the cut-bank.
\nThe Town Highway 1 crossing of the Saxtons River is a 184-ft-long, two-lane bridge \nconsisting of three steel-beam spans (Vermont Agency of Transportation, written communication, March 30, 1995). \nThe bridge is supported by vertical, concrete, skeletal-style abutment walls with spill-through embankments adjacent to \neach wall. The channel is skewed approximately 35 degrees to the opening while the opening-skew-to-roadway is 30 \ndegrees.
\nThe only scour protection measure at the site was type-3 stone fill (less than 48 inches \ndiameter) on the spill-through embankments. Additional details describing conditions at the \nsite are included in the Level II Summary and Appendices D \nand E.
\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a \nhighway crossing is comprised of three components: 1) long-term streambed degradation; \n2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) \nand; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is \nthe sum of the three components. Equations are available to compute depths for contraction \nand local scour and a summary of the results of these computations follows.
\nThere was no computed contraction scour for all modelled flows at this site. Abutment \nscour ranged from 9.0 to 13.4 feet. The worst-case abutment scour occurred at the 500-year \ndischarge for the left abutment. There are two piers for which computed pier scour ranged \nfrom 9.0 to 18.4 feet. The left and right piers in this report are presented as pier 1 and pier 2, \nrespectively. The worst-case pier scour occurred at pier 2 for 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/ofr97345","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Boehmler, E.M., 1997, Level II scour analysis for Bridge 11R (ROCKTH0001011R) on Town Highway 1 (VT 121 & FAS 125), crossing the Saxtons River, Rockingham, Vermont: U.S. Geological Survey Open-File Report 97-345, iv, 49 p., https://doi.org/10.3133/ofr97345.","productDescription":"iv, 49 p.","numberOfPages":"54","costCenters":[],"links":[{"id":170100,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97345.GIF"},{"id":279768,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0345/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Rockingham","otherGeospatial":"Saxtons 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":"4f4e4b1ae4b07f02db6a83de","contributors":{"authors":[{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240472,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":49918,"text":"ofr97346 - 1997 - Level II scour analysis for Bridge 43 (BENNCYDEPO0043) on Depot Street, crossing the Walloomsac River, Bennington, Vermont","interactions":[],"lastModifiedDate":"2014-01-05T12:21:42","indexId":"ofr97346","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":"97-346","title":"Level II scour analysis for Bridge 43 (BENNCYDEPO0043) on Depot Street, crossing the Walloomsac River, Bennington, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nBENNCYDEPO0043 on the Depot Street crossing of the Walloomsac River, Bennington, \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 \nsouthwestern Vermont. The 30.1-mi2\n drainage area is a predominantly rural and forested \nbasin. The bridge site is located within an urban setting in the Town of Bennington with \nbuildings and parking lots on overbanks.
\nIn the study area, the Walloomsac River has a straight channel with constructed channel \nbanks through much of the reach. The channel is located on a delta and has a slope of \napproximately 0.02 ft/ft, an average channel top width of 48 ft and an average bank height \nof 6 ft. The predominant channel bed material is cobble with a median grain size (D50) of \n108 mm (0.356 ft). The geomorphic assessment at the time of the Level I and Level II site \nvisit on August 5, 1996, indicated that the reach was stable.
\nThe Depot Street crossing of the Walloomsac River is a 46-ft-long, two-lane bridge \nconsisting of one 40-foot concrete span (Vermont Agency of Transportation, written \ncommunication, December 13, 1995). The bridge is supported by vertical, concrete \nabutments with wingwalls. The channel is skewed approximately \n5 degrees to the opening and the opening-skew-to-roadway is 15 degrees.
\nScour countermeasures at the site include type-2 stone fill (less than 36 inches diameter) at \nthe upstream end of the upstream right wing wall and type-1 stone fill (less than 12 inches \ndiameter) along the base of the upstream left wing wall. Downstream banks are protected by \nconcrete and stone walls. The upstream right bank is protected by alternating type-2 stone \nfill and masonry walls. Additional details describing conditions at the site are included in \nthe 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 computed for all modelled flows ranged from 0.0 to 4.1 ft. \nThe worst-case contraction scour occurred at the 500-year discharge. \nComputed right abutment scour ranged from 2.9 to 13.4 ft. with the worst-case \nscour occurring at the 500-year discharge. Computed left abutment scour \nranged from 5.6 to 16.3 ft. with the worst-case scour also occurring at the 500-year discharge. \nAdditional information on scour depths and depths to armoring are included in the section titled \n“Scour Results”. Scoured-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 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/ofr97346","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Olson, S.A., 1997, Level II scour analysis for Bridge 43 (BENNCYDEPO0043) on Depot Street, crossing the Walloomsac River, Bennington, Vermont: U.S. Geological Survey Open-File Report 97-346, iv, 50 p., https://doi.org/10.3133/ofr97346.","productDescription":"iv, 50 p.","numberOfPages":"55","costCenters":[],"links":[{"id":170101,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":279767,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0346/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Bennington","otherGeospatial":"Walloomsac River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -73.25,42.75 ], [ -73.25,43.0 ], [ -73.125,43.0 ], [ -73.125,42.75 ], [ -73.25,42.75 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a615b","contributors":{"authors":[{"text":"Olson, Scott A. 0000-0002-1064-2125 solson@usgs.gov","orcid":"https://orcid.org/0000-0002-1064-2125","contributorId":2059,"corporation":false,"usgs":true,"family":"Olson","given":"Scott","email":"solson@usgs.gov","middleInitial":"A.","affiliations":[{"id":405,"text":"NH/VT office of New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240473,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":49919,"text":"ofr97362 - 1997 - Level II scour analysis for Bridge 7 (CHESTH00030007) on Town Highway 3, crossing the South Branch Williams River, Chester, Vermont","interactions":[],"lastModifiedDate":"2014-01-04T15:31:30","indexId":"ofr97362","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":"97-362","title":"Level II scour analysis for Bridge 7 (CHESTH00030007) on Town Highway 3, crossing the South Branch Williams River, Chester, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nCHESTH00030007 on Town Highway 3 which is also State Route 35 crossing the South \nBranch Williams River, Chester, Vermont (figures 1–8). A Level II study is a basic \nengineering analysis of the site, including a quantitative analysis of stream stability and \nscour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation \nalso are included 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 southern Vermont. The 10.4-mi2 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 while the immediate bank has some trees. Downstream of the bridge and the upstream \nleft bank are forested.
\nIn the study area, the South Branch Williams River has an incised, sinuous channel with a \nslope of approximately 0.03 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 boulder with a median grain \nsize (D50) of 70.5 mm (0.231 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on August 26, 1996, indicated that the reach was laterally unstable. There \nare cutbanks on both the left and right banks alternating with point bars in the upstream \nreach.
\nThe Town Highway 3 (VT 35) crossing of the South Branch Williams River is a 74-ft-long, \ntwo-lane bridge consisting of one 72-foot steel-beam span (Vermont Agency of \nTransportation, written communication, March 30, 1995). The bridge is supported by spill-\nthrough abutments. The channel is skewed approximately 5 degrees to the opening and the \nopening-skew-to-roadway is also 5 degrees.
\nThree channel scour holes 1.0 ft deeper than the mean thalweg depth were observed during \nthe Level I assessment in the upstream reach. There are no scour protection measures at the \nsite. 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 0.4 ft. The worst-case \ncontraction scour occurred at the 100-year. Abutment scour ranged from 4.1 to 15.5 ft. The \nworst-case abutment scour occurred at the 500-year. Additional information on scour \ndepths and depths to armoring are included in the section titled “Scour Results”. Scoured-\nstreambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. \nA cross-section of the scour computed at the bridge is presented in figure 8. Scour depths \nwere calculated assuming an infinite depth of erosive material and a homogeneous particle-\nsize distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97362","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Burns, R.L., 1997, Level II scour analysis for Bridge 7 (CHESTH00030007) on Town Highway 3, crossing the South Branch Williams River, Chester, Vermont: U.S. Geological Survey Open-File Report 97-362, iv, 50 p., https://doi.org/10.3133/ofr97362.","productDescription":"iv, 50 p.","numberOfPages":"55","costCenters":[],"links":[{"id":170102,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97362.GIF"},{"id":279766,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0362/report.pdf"}],"scale":"62500","country":"United States","state":"Vermont","city":"Chester","otherGeospatial":"South Branch Williams River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.0 ], [ -72.75,43.5 ], [ -72.5,43.5 ], [ -72.5,43.0 ], [ -72.75,43.0 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b16e4b07f02db6a576d","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240474,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":49999,"text":"ofr97760 - 1997 - Level II scour analysis for Bridge 4 (MAIDTH00070004) on Town Highway 7, crossing Cutler Mill Brook, Maidstone, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T12:28:59","indexId":"ofr97760","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-760","title":"Level II scour analysis for Bridge 4 (MAIDTH00070004) on Town Highway 7, crossing Cutler Mill Brook, Maidstone, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nMAIDTH00070004 on Town Highway 7 crossing the Cutler Mill Brook, Maidstone, \nVermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including \na quantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.
\nThe site is in the White Mountain section of the New England physiographic province in \nnortheastern Vermont. The 18.1-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is predominantly shrub and \nbrushland.
\nIn the study area, the Cutler Mill Brook has a non-incised, meandering channel with local \nbraiding and a slope of approximately 0.004 ft/ft, an average channel top width of 43 ft and \nan average bank height of 2 ft. The channel bed material ranges from sand to cobble with a \nmedian grain size (D50) of 27.6 mm (0.091 ft). The geomorphic assessment at the time of \nthe Level I and Level II site visit on July 19, 1995, indicated that the reach was laterally \nunstable due to large meanders in the channel.
\nThe Town Highway 7 crossing of the Cutler Mill Brook is a 25-ft-long, one-lane bridge \nconsisting of one 22-foot concrete span (Vermont Agency of Transportation, written \ncommunication, August 5, 1994). The opening length of the structure parallel to the bridge \nface is 21.7 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The \nchannel is skewed approximately 20 degrees to the opening while the opening-skew-to-roadway is 0 degrees.
\nA scour hole 2.0 ft deeper than the mean thalweg depth was observed along the left \nabutment during the Level I assessment. The only scour protection measure at the site was \ntype-2 stone fill (less than 36 inches diameter) along both banks upstream, along the entire \nbase length of the upstream left wingwall, and along the upstream end of the upstream right \nwingwall. Additional details describing conditions at the site are included in the Level II \nSummary and Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge was determined and analyzed as another potential worst-case scour scenario. \nTotal scour at a highway crossing is comprised of three components: 1) long-term \nstreambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction \nin flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.
\nContraction scour for all modelled flows ranged from 2.2 to 4.2 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 5.7 to \n12.4 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97760","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Striker, L.K., and Medalie, L., 1997, Level II scour analysis for Bridge 4 (MAIDTH00070004) on Town Highway 7, crossing Cutler Mill Brook, Maidstone, Vermont: U.S. Geological Survey Open-File Report 97-760, iv, 51 p., https://doi.org/10.3133/ofr97760.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176340,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97760.GIF"},{"id":279679,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0760/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Maidstone","otherGeospatial":"Cutler Mill Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -71.625,44.5 ], [ -71.625,44.625 ], [ -71.5,44.625 ], [ -71.5,44.5 ], [ -71.625,44.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a61ed","contributors":{"authors":[{"text":"Striker, Lora K.","contributorId":41481,"corporation":false,"usgs":true,"family":"Striker","given":"Lora","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":240611,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Medalie, Laura 0000-0002-2440-2149 lmedalie@usgs.gov","orcid":"https://orcid.org/0000-0002-2440-2149","contributorId":3657,"corporation":false,"usgs":true,"family":"Medalie","given":"Laura","email":"lmedalie@usgs.gov","affiliations":[{"id":466,"text":"New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240610,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50000,"text":"ofr97765 - 1997 - Level II scour analysis for Bridge 4 (RYEGTH00050004) on Town Highway 5, crossing the Wells River, Ryegate, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T16:18:31","indexId":"ofr97765","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-765","title":"Level II scour analysis for Bridge 4 (RYEGTH00050004) on Town Highway 5, crossing the Wells River, Ryegate, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nRYEGTH00050004 on Town Highway 5 crossing the Wells River, Ryegate, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.\nThe site is in the New England Upland section of the New England physiographic province \nin eastern Vermont. The 84.7-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover includes shrubs and brush on the \nupstream left bank and downstream right bank of the bridge. The upstream right bank and \ndownstream left bank of the bridge is forested.\nIn the study area, the Wells River has an incised, sinuous channel with a slope of \napproximately 0.008 ft/ft, an average channel top width of 107 ft and an average bank \nheight of 11 ft. The channel bed material ranges from gravel to boulder with a median grain \nsize (D50) of 67.4 mm (0.221 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on August 21, 1995, indicated that the reach was laterally unstable with \nmass wasting along the upstream right bank.\nThe Town Highway 5 crossing of the Wells River is a 108-ft-long, two-lane bridge \nconsisting of a 100-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, March 27, 1995). The opening length of the structure parallel to the bridge \nface is 93.4 ft. The bridge is supported by vertical, stone block abutments with wingwalls. \nThe channel is skewed approximately 50 degrees to the opening while the opening-skew-toroadway is 45 degrees. \nThe scour protection counter-measures at the site included type-1 stone fill (less than 12 \ninches diameter) along the downstream left road embankment. Also, type-2 stone fill (less \nthan 36 inches diameter) along the upstream right wingwall, extending 30 feet upstream \nalong the right bank, along the downstream end of the downstream right wingwall, along \nthe downstream right road embankment, and along the downstream left bank below the old \nrailroad bed. Additional details describing conditions at the site are included in the Level II \nSummary and Appendices D and E.\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. Total scour at a highway crossing is comprised of \nthree components: 1) long-term streambed degradation; 2) contraction scour (due to \naccelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused \nby accelerated flow around piers and abutments). Total scour is the sum of the three \ncomponents. Equations are available to compute depths for contraction and local scour and \na summary of the results of these computations follows.\nContraction scour for all modelled flows ranged from 1.8 to 2.6 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 10.2 to \n22.6 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution. \nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97765","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., and Hammond, R.E., 1997, Level II scour analysis for Bridge 4 (RYEGTH00050004) on Town Highway 5, crossing the Wells River, Ryegate, Vermont: U.S. Geological Survey Open-File Report 97-765, iv, 48 p., https://doi.org/10.3133/ofr97765.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":176341,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97765.PNG"},{"id":279678,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0765/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Ryegate","otherGeospatial":"Wells River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.25,44.125 ], [ -72.25,44.25 ], [ -72.125,44.25 ], [ -72.125,44.125 ], [ -72.25,44.125 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a6209","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240612,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hammond, Robert E.","contributorId":61862,"corporation":false,"usgs":true,"family":"Hammond","given":"Robert","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":240613,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50001,"text":"ofr97766 - 1997 - Level II scour analysis for Bridge 46 (BRNETH00610046) on Town Highway 61, crossing East Peacham Brook, Barnet, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T16:11:32","indexId":"ofr97766","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-766","title":"Level II scour analysis for Bridge 46 (BRNETH00610046) on Town Highway 61, crossing East Peacham Brook, Barnet, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nBRNETH00610046 on Town Highway 61 crossing East Peacham Brook, Barnet, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.\nThe site is in the New England Upland section of the New England physiographic province \nin east-central Vermont. The 15.8-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is forest.\nIn the study area, East Peacham Brook has an incised, sinuous channel with a slope of \napproximately 0.02 ft/ft, an average channel top width of 59 ft and an average bank height \nof 5 ft. The channel bed material ranges from gravel to boulder with a median grain size \n(D50) of 121 mm (0.397 ft). The geomorphic assessment at the time of the Level I and Level \nII site visit on August 23, 1995, indicated that the reach was laterally unstable with cut \nbanks both upstream and downstream of the bridge.\nThe Town Highway 61 crossing of East Peacham Brook is a 28-ft-long, one-lane bridge \nconsisting of one 26-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, March 24, 1995). The opening length of the structure parallel to the bridge \nface is 24.5 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The \nchannel is skewed approximately 5 degrees to the opening while the opening-skew-toroadway is zero degrees. \nA scour hole 0.7 ft deeper than the mean thalweg depth was observed along the upstream \nleft wingwall extending along the left abutment during the Level I assessment. The only \nscour protection measure at the site was type-2 stone fill (less than 36 inches diameter) at \nthe upstream end of the upstream left wingwall extending along the upstream left bank and \nalong the entire base of the downstream left wingwall. Additional details describing \nconditions at the site are included in the Level II Summary and Appendices D and E.\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge is determined and analyzed as another potential worst-case scour scenario. Total \nscour at a highway crossing is comprised of three components: 1) long-term streambed \ndegradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow \narea at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.\nContraction scour for all modelled flows ranged from 0 to 1.2 ft. The worst-case contraction \nscour occurred at the 500-year discharge. Abutment scour ranged from 10.4 to 13.9 ft. The \nworst-case abutment scour occurred at the 500-year discharge. Additional information on \nscour depths and depths to armoring are included in the section titled “Scour Results”. \nScoured-streambed elevations, based on the calculated scour depths, are presented in tables \n1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour \ndepths were calculated assuming an infinite depth of erosive material and a homogeneous \nparticle-size distribution. \nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97766","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., 1997, Level II scour analysis for Bridge 46 (BRNETH00610046) on Town Highway 61, crossing East Peacham Brook, Barnet, Vermont: U.S. Geological Survey Open-File Report 97-766, iv, 51 p., https://doi.org/10.3133/ofr97766.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176342,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97766.PNG"},{"id":279677,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0766/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Barnet","otherGeospatial":"East Peacham Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.25,44.25 ], [ -72.25,44.375 ], [ -72.0,44.375 ], [ -72.0,44.25 ], [ -72.25,44.25 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a60f8","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240614,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":50003,"text":"ofr97768 - 1997 - Level II scour analysis for Bridge 22 (WALDTH00180022) on Town Highway 18, crossing Coles Brook, Walden, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T16:01:28","indexId":"ofr97768","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-768","title":"Level II scour analysis for Bridge 22 (WALDTH00180022) on Town Highway 18, crossing Coles Brook, Walden, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nWALDTH00180022 on Town Highway 18 crossing Coles Brook also known as Joes \nBrook, Walden, Vermont (figures 1–8). A Level II study is a basic engineering analysis of \nthe site, including a quantitative analysis of stream stability and scour (U.S. Department of \nTransportation, 1993). Results of a Level I scour investigation also are included in \nAppendix E of this report. A Level I investigation provides a qualitative geomorphic \ncharacterization of the study site. Information on the bridge, gleaned from Vermont Agency \nof Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II \nanalyses and is found in Appendix D.\nThe site is in the New England Upland section of the New England physiographic province \nin northeastern Vermont. The 12.5-mi2\n drainage area is in a predominantly rural and \nforested basin. In the vicinity of the study site, the surface cover is predominantly forested \nwhile the downstream left bank is shrub and brushland.\nIn the study area, the Coles Brook has an incised, sinuous channel with a slope of \napproximately 0.004 ft/ft, an average channel top width of 54 ft and an average bank height \nof 4 ft. The channel bed material ranges from gravel to bedrock with a median grain size \n(D50) of 124.1 mm (0.407 ft). The D50 was taken from a pebble count in the downstream \nchannel, because the upstream channel is primarily bedrock. The geomorphic assessment at \nthe time of the Level I and Level II site visit on August 8, 1995, indicated that the reach was \nstable.\nThe Town Highway 18 crossing of the Coles Brook is a 46-ft-long, one-lane bridge \nconsisting of one 44-foot steel-beam span with a wooden deck (Vermont Agency of \nTransportation, written communication, April 5, 1995). The opening length of the structure \nparallel to the bridge face is 41.4 ft. The bridge is supported by a vertical, concrete abutment \nwith wingwalls on the left and by a vertical, stone abutment with stone wingwalls with a \nconcrete cap on the right. The channel is skewed approximately 5 degrees to the opening \nwhile the computed opening-skew-to-roadway is 10 degrees. \nThe only scour protection measure at the site was a stone wall along the upstream left bank \nand type-2 stone fill (less than 36 inches diameter) along the entire base length of the \nupstream left wingwall, left abutment, and downstream left wing wall. Additional details \ndescribing conditions at the site are included in the Level II Summary and Appendices D \nand E.\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100-year and 500-year discharges. Total scour at a highway crossing is comprised of \nthree components: 1) long-term streambed degradation; 2) contraction scour (due to \naccelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused \nby accelerated flow around piers and abutments). Total scour is the sum of the three \ncomponents. Equations are available to compute depths for contraction and local scour and \na summary of the results of these computations follows.\nContraction scour for all modelled flows was 0.0 ft. Abutment scour ranged from 6.4 to 7.9 \nft at the left abutment and from 11.8 to 14.9 ft at the right abutment. The worst-case \nabutment scour occurred at the 500-year discharge. Additional information on scour depths \nand depths to armoring are included in the section titled “Scour Results”. Scouredstreambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. \nA cross-section of the scour computed at the bridge is presented in figure 8. Scour depths \nwere calculated assuming an infinite depth of erosive material and a homogeneous particlesize distribution. \nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97768","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Striker, L.K., and Ivanoff, M.A., 1997, Level II scour analysis for Bridge 22 (WALDTH00180022) on Town Highway 18, crossing Coles Brook, Walden, Vermont: U.S. Geological Survey Open-File Report 97-768, iv, 48 p., https://doi.org/10.3133/ofr97768.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":176344,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97768.PNG"},{"id":279675,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0768/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Walden","otherGeospatial":"Coles Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.25,44.375 ], [ -72.25,44.5 ], [ -72.0,44.5 ], [ -72.0,44.375 ], [ -72.25,44.375 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a810d","contributors":{"authors":[{"text":"Striker, Lora K.","contributorId":41481,"corporation":false,"usgs":true,"family":"Striker","given":"Lora","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":240617,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240616,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50005,"text":"ofr97770 - 1997 - Level II scour analysis for Bridge 8 (WELLTH00020008) on Town Highway 2, crossing Wells Brook, Wells, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T15:28:52","indexId":"ofr97770","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-770","title":"Level II scour analysis for Bridge 8 (WELLTH00020008) on Town Highway 2, crossing Wells Brook, Wells, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nWELLTH00020008 on Town Highway 2 crossing the Wells Brook, Wells, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.\nThe site is in the Taconic section of the New England physiographic province in southwestern Vermont. The 14.4-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover on the right overbanks is \npredominantly suburban while the immediate banks are vegetated with trees and brush. The \nleft bank upstream and downstream is predominantly pasture.\nIn the study area, the Wells Brook has an incised, straight channel with a slope of \napproximately 0.005 ft/ft, an average channel top width of 51 ft and an average bank height \nof 7 ft. The channel bed material ranges from gravel to boulder with a median grain size \n(D50) of 48.6 mm (0.159 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on September 19, 1995, indicated that the reach was stable.\nThe Town Highway 2 crossing of the Wells Brook is a 35-ft-long, two-lane bridge \nconsisting of one 32-foot concrete span (Vermont Agency of Transportation, written \ncommunication, March 22, 1995). The opening length of the structure parallel to the bridge \nface is 31.7 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The \nchannel is skewed approximately 10 degrees to the opening while the opening-skew-toroadway is 5 degrees. \nA scour hole 1.5 ft deeper than the mean thalweg depth was observed along the left \nabutment during the Level I assessment. The only scour protection measure at the site was \ntype-2 stone fill (less than 36 inches diameter) along the left bank upstream, and type-5 \n(placed stone wall) at the upstream end of the upstream left wingwall, at the downstream \nend of the downstream left wingwall, and along the downstream left bank. Additional \ndetails describing conditions at the site are included in the Level II Summary and \nAppendices D and E.\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge is determined and analyzed as another potential worst-case scour scenario. Total \nscour at a highway crossing is comprised of three components: 1) long-term streambed \ndegradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow \narea at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.\nContraction scour for all modelled flows ranged from 0.0 to 0.8 ft. The worst-case \ncontraction scour occurred at the incipient roadway-overtopping discharge, which was less \nthan the 100-year discharge. Abutment scour ranged from 5.6 to 10.0 ft at the left abutment \nand from 3.1 to 4.2 ft at the right abutment. The worst-case abutment scour occurred at the \nincipient roadway-overtopping discharge at the left abutment. Additional information on \nscour depths and depths to armoring are included in the section titled “Scour Results”. \nScoured-streambed elevations, based on the calculated scour depths, are presented in tables \n1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour \ndepths were calculated assuming an infinite depth of erosive material and a homogeneous \nparticle-size distribution. \nUsually, computed scour depths are evaluated in combination with other information \nincluding (but not limited to) historical performance during flood events, the geomorphic \nstability assessment, existing scour protection measures, and the results of the hydraulic \nanalyses. Therefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97770","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Striker, L.K., and Ivanoff, M.A., 1997, Level II scour analysis for Bridge 8 (WELLTH00020008) on Town Highway 2, crossing Wells Brook, Wells, Vermont: U.S. Geological Survey Open-File Report 97-770, iv, 51 p., https://doi.org/10.3133/ofr97770.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176713,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97770.PNG"},{"id":279673,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0770/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Wells","otherGeospatial":"Wells Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -73.25,43.375 ], [ -73.25,43.5 ], [ -73.125,43.5 ], [ -73.125,43.375 ], [ -73.25,43.375 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b16e4b07f02db6a5639","contributors":{"authors":[{"text":"Striker, Lora K.","contributorId":41481,"corporation":false,"usgs":true,"family":"Striker","given":"Lora","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":240621,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240620,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50006,"text":"ofr97771 - 1997 - Level II scour analysis for Bridge 41 (ANDOVT00110041) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T12:32:19","indexId":"ofr97771","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-771","title":"Level II scour analysis for Bridge 41 (ANDOVT00110041) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure ANDOVT00110041 on State Route 11 crossing the Middle Branch Williams River, Andover, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.
The site is in the Green Mountain section of the New England physiographic province in southeastern Vermont. The 12.1-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is grass on the upstream right overbank while the immediate banks have dense woody vegetation. The upstream left overbank and downstream right overbank are brushland. The downstream left overbank is forested.
In the study area, the Middle Branch Williams River has an incised, sinuous channel with a slope of approximately 0.018 ft/ft, an average channel top width of 71 ft and an average bank height of 4 ft. The channel bed material ranges from gravel to boulders with a median grain size (D50) of 85.0 mm (0.279 ft). The geomorphic assessment at the time of the Level I and Level II site visit on September 10, 1996, indicated that the reach was laterally unstable due to a cut-bank present on the upstream right bank and a wide channel bar with vegetation in the upstream reach.
The State Route 11 crossing of the Middle Branch Williams River is a 46-ft-long, two-lane bridge consisting of a concrete 44-foot tee-beam span (Vermont Agency of Transportation, written communication, March 29, 1995). The opening length of the structure parallel to the bridge face is 42 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 35 degrees to the opening while the opening-skew-toroadway is zero degrees.
A scour hole 0.8 ft deeper than the mean thalweg depth was observed along the downstream end of the left abutment and downstream left wingwall during the Level I assessment. Type- 2 stone fill (less than 36 inches diameter) protects the upstream end of the upstream left wingwall, the downstream ends of the downstream left and right wingwalls and the downstream right road embankment. Type-3 stone fill protects the upstream end of the upstream right wingwall and the upstream right bank. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.
Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). In addition, the incipient roadway-overtopping discharge was determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for all modelled flows ranged from 0.0 to 2.1 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 11.1 to 18.7 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.
It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97771","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., and Hammond, R.E., 1997, Level II scour analysis for Bridge 41 (ANDOVT00110041) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont: U.S. Geological Survey Open-File Report 97-771, iv, 52 p., https://doi.org/10.3133/ofr97771.","productDescription":"iv, 52 p.","numberOfPages":"57","costCenters":[],"links":[{"id":176714,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97771.PNG"},{"id":279672,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0771/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Andover","otherGeospatial":"Williams River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -73.125,44.375 ], [ -73.125,44.5 ], [ -73.0,44.5 ], [ -73.0,44.375 ], [ -73.125,44.375 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a61ab","contributors":{"authors":[{"text":"Wild, Emily C. 0000-0001-6157-7629 ecwild@usgs.gov","orcid":"https://orcid.org/0000-0001-6157-7629","contributorId":1810,"corporation":false,"usgs":true,"family":"Wild","given":"Emily","email":"ecwild@usgs.gov","middleInitial":"C.","affiliations":[{"id":5081,"text":"Libraries","active":false,"usgs":true}],"preferred":false,"id":240622,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hammond, Robert E.","contributorId":61862,"corporation":false,"usgs":true,"family":"Hammond","given":"Robert","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":240623,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50008,"text":"ofr97772 - 1997 - Level II scour analysis for Bridge 18 (SHEFTH00410018) on Town Highway 41, crossing Millers Run, Sheffield, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T14:15:28","indexId":"ofr97772","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-772","title":"Level II scour analysis for Bridge 18 (SHEFTH00410018) on Town Highway 41, crossing Millers Run, Sheffield, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure SHEFTH00410018 on Town Highway 41 crossing Millers Run, Sheffield, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.
The site is in the White Mountain section of the New England physiographic province in northeastern Vermont. The 16.2-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is grass upstream and downstream of the bridge while the immediate banks have dense woody vegetation.
In the study area, Millers Run has an incised, straight channel with a slope of approximately 0.01 ft/ft, an average channel top width of 50 ft and an average bank height of 6 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) of 50.9 mm (0.167 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 1, 1995, indicated that the reach was laterally unstable, which is evident in the moderate to severe fluvial erosion in the upstream reach.
The Town Highway 41 crossing of the Millers Run is a 30-ft-long, one-lane bridge consisting of a 28-foot steel-stringer span (Vermont Agency of Transportation, written communication, March 28, 1995). The opening length of the structure parallel to the bridge face is 22.2 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 20 degrees to the opening. The computed opening-skewto-roadway is 5 degrees, while it is zero degrees in the historical form.
A scour hole 1.0 ft deeper than the mean thalweg depth was observed along the left abutment during the Level I assessment. The scour protection measure at the site includes type-1 stone fill (less than 12 inches diameter) along the upstream right wingwall and the upstream left wingwall. Type-2 stone fill (less than 36 inches diameter) extends along the downstream end of the downstream left wingwall, the upstream right bank and the downstream left bank. The downstream right bank is protected by type-2 stone fill and a stone masonry wall. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.
Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge is determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for all modelled flows ranged from 0.2 to 1.8 ft. The worst-case contraction scour occurred at the 100-year and 500-year discharges. Left abutment scour ranged from 14.1 to 16.4 ft. The worst-case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 6.9 to 9.3 ft. The worst-case right abutment scour occurred at the incipient roadway-overtopping discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.
It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97772","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., and Boehmler, E.M., 1997, Level II scour analysis for Bridge 18 (SHEFTH00410018) on Town Highway 41, crossing Millers Run, Sheffield, Vermont: U.S. Geological Survey Open-File Report 97-772, iv, 51 p., https://doi.org/10.3133/ofr97772.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176806,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97772.PNG"},{"id":279671,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0772/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Sheffield","otherGeospatial":"Millers Run","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a81cb","contributors":{"authors":[{"text":"Wild, Emily C. 0000-0001-6157-7629 ecwild@usgs.gov","orcid":"https://orcid.org/0000-0001-6157-7629","contributorId":1810,"corporation":false,"usgs":true,"family":"Wild","given":"Emily","email":"ecwild@usgs.gov","middleInitial":"C.","affiliations":[{"id":5081,"text":"Libraries","active":false,"usgs":true}],"preferred":false,"id":240625,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240626,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49993,"text":"ofr97753 - 1997 - Level II scour analysis for Bridge 45 (BRNETH00070045) on Town Highway 7, crossing the Stevens River, Barnet, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T13:29:28","indexId":"ofr97753","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":"97-753","title":"Level II scour analysis for Bridge 45 (BRNETH00070045) on Town Highway 7, crossing the Stevens River, Barnet, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nBRNETH00070045 on Town Highway 7 crossing the Stevens River, Barnet, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.
\nThe site is in the New England Upland section of the New England physiographic province \nin east-central Vermont. The 41.5-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is forest upstream and pasture \ndownstream of the bridge while the immediate banks have dense woody vegetation.
\nIn the study area, the Stevens River has an incised, sinuous channel with a slope of \napproximately 0.02 ft/ft, an average channel top width of 100 ft and an average bank height \nof 17 ft. The channel bed material ranges from gravel to boulder with a median grain size \n(D50) of 105 mm (0.344 ft). The geomorphic assessment at the time of the Level I and Level \nII site visit on August 22, 1995, indicated that the reach was stable.
\nThe Town Highway 7 crossing of the Stevens River is a 37-ft-long, two-lane bridge \nconsisting of one 34-foot concrete slab span (Vermont Agency of Transportation, written \ncommunication, March 16, 1995). The opening length of the structure parallel to the bridge \nface is 33 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The \nchannel is skewed approximately 10 degrees to the opening while the opening-skew-to-roadway is 20 degrees.
\nThe only scour protection measure at the site was type-2 stone fill (less than 36 inches \ndiameter) along the entire left and right abutments, upstream and downstream wingwalls, \nand upstream and downstream banks. 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 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 0.8 to 5.4 ft. The worst-case \ncontraction scour occurred at the incipient roadway-overtopping discharge, which was \ngreater than the 100-year discharge. Left abutment scour ranged from 21.8 to 28.6 ft. The \nworst-case left abutment scour occurred at the 500-year discharge. Right abutment scour \nranged from 14.6 to 17.4 ft. The worst-case right abutment scour occurred at the incipient \nroadway-overtopping discharge. Additional information on scour depths and depths to \narmoring are included in the section titled “Scour Results”. Scoured-streambed elevations, \nbased on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the \nscour computed at the bridge is presented in figure 8. Scour depths were calculated \nassuming an infinite depth of erosive material and a homogeneous particle-size distribution.
\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/ofr97753","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., and Hammond, R.E., 1997, Level II scour analysis for Bridge 45 (BRNETH00070045) on Town Highway 7, crossing the Stevens River, Barnet, Vermont: U.S. Geological Survey Open-File Report 97-753, iv, 51 p., https://doi.org/10.3133/ofr97753.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176840,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97753.GIF"},{"id":279685,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0753/report.pdf"}],"scale":"25000","country":"United States","state":"Vermont","city":"Barnet","otherGeospatial":"Stevens River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.25,44.25 ], [ -72.25,44.375 ], [ -72.0,44.375 ], [ -72.0,44.25 ], [ -72.25,44.25 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a60fa","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240599,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hammond, Robert E.","contributorId":61862,"corporation":false,"usgs":true,"family":"Hammond","given":"Robert","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":240600,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":49955,"text":"ofr97423 - 1997 - Level II scour analysis for Bridge 63 (CHESTH00090063) on Town Highway 9, crossing the Williams River, Chester, Vermont","interactions":[],"lastModifiedDate":"2013-12-19T10:08:17","indexId":"ofr97423","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":"97-423","title":"Level II scour analysis for Bridge 63 (CHESTH00090063) on Town Highway 9, crossing the Williams River, Chester, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nCHESTH00090063 on Town Highway 9 crossing the Williams River, Chester, 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 24.0-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is grass with trees and brush along \nthe immediate banks.\nIn the study area, the the Williams River has an incised, sinuous channel with a slope of \napproximately 0.005 ft/ft, an average channel top width of 64 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 57.7 mm (0.189 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on September 18, 1996, indicated that the reach was stable.\nThe Town Highway 9 crossing of the Williams River is a 45-ft-long, two-lane bridge \nconsisting of one 35-foot steel-beam span with a timber deck (Vermont Agency of \nTransportation, written communication, April 6, 1995). The bridge is supported by vertical, \nconcrete abutments with wingwalls. The channel is skewed approximately 5 degrees to the \nopening while the opening-skew-to-roadway is 0 degrees.\nA scour hole 1.8 ft deeper than the mean thalweg depth was observed along the left \nabutment during the Level I assessment. The scour hole undermines the left abutment and \nextends from 50 ft upstream of the upstream bridge face to 50 ft downstream of the \ndownstream bridge face. The scour protection measures at the site included type-3 stone fill \n(less than 48 inches diameter) under the bridge along the entire base length of the right \nabutment and along the right bank from 50 to 88 ft upstream. Type-2 (less than 36 inches \ndiameter) stone fill scour protection was observed along the downstream left bank from 18 \nft to 115 ft, along the downstream right bank from 8 ft to 25 ft and along the upstream left \nbank from 50 to 75 ft. 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 was computed to be 0.0 ft. Abutment scour ranged \nfrom 10.1 ft to 11.0 ft along the left abutment and from 14.1 ft to 15.1 ft along the right \nabutment. The worst-case abutment scour for the left abutment occurred at the 500-year \ndischarge while the worst-case abutment scour for the right abutment occurred at the 100-\nyear discharge. Additional information on scour depths and depths to armoring are included \nin the 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/ofr97423","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Flynn, R.H., 1997, Level II scour analysis for Bridge 63 (CHESTH00090063) on Town Highway 9, crossing the Williams River, Chester, Vermont: U.S. Geological Survey Open-File Report 97-423, iv, 50 p., https://doi.org/10.3133/ofr97423.","productDescription":"iv, 50 p.","numberOfPages":"55","costCenters":[],"links":[{"id":176454,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97423.PNG"},{"id":279727,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0423/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Chester","otherGeospatial":"Williams River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.625,43.25 ], [ -72.625,43.375 ], [ -72.5,43.375 ], [ -72.5,43.25 ], [ -72.625,43.25 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b16e4b07f02db6a5911","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":240534,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":50010,"text":"ofr97774 - 1997 - Level II scour analysis for Bridge 29 (DORSTH00100029) on Town Highway 10, crossing the Mettawee River, Dorset, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T13:29:02","indexId":"ofr97774","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-774","title":"Level II scour analysis for Bridge 29 (DORSTH00100029) on Town Highway 10, crossing the Mettawee River, Dorset, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure DORSTH00100029 on Town Highway 10 crossing the Mettawee River, Dorset, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.
The site is in the Taconic section of the New England physiographic province in southwestern Vermont. The 9.5-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest on the upstream left overbank and the upstream and downstream right overbanks. The downstream left overbank is pasture and brushland.
In the study area, the Mettawee River has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 66 ft and an average bank height of 8 ft. The channel bed material ranges from gravel to boulders with a median grain size (D50) of 79.0 mm (0.259 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 5, 1996, indicated that the reach was stable.
The Town Highway 10 crossing of the Mettawee River is a 26-ft-long, two-lane bridge consisting of a 24-ft steel-stringer span (Vermont Agency of Transportation, written communication, September 28, 1995). The opening length of the structure parallel to the bridge face is 24.1 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 45 degrees to the opening while the opening-skew-to-roadway is zero degrees.
At the upstream end of the right abutment, there is a scour hole 1.0 ft deeper than the mean thalweg depth. Scour counter-measures at the site include type-1 stone fill (less than 12 inches diameter) along the downstream right wingwall. Type-2 stone fill (less than 36 inches diameter) is present along the downstream left and right banks. Type-3 stone fill (less than 48 inches diameter) is present along the upstream left bank and sparsely in front of the right abutment. A concrete wall (old abutment) extends along the upstream right bank. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.
Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. In addition, the incipient roadway-overtopping discharge is determined and analyzed as another potential worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for all modelled flows ranged from 0.4 to 1.9 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 10.5 to 10.8 ft. The worst-case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 11.4 to 11.9 ft. The worst-case right abutment scour occurred at the 100-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.
It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97774","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., 1997, Level II scour analysis for Bridge 29 (DORSTH00100029) on Town Highway 10, crossing the Mettawee River, Dorset, Vermont: U.S. Geological Survey Open-File Report 97-774, iv, 51 p., https://doi.org/10.3133/ofr97774.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":176808,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97774.PNG"},{"id":279669,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0774/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Dorset","otherGeospatial":"Mettawee River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b19e4b07f02db6a7f30","contributors":{"authors":[{"text":"Wild, Emily C. 0000-0001-6157-7629 ecwild@usgs.gov","orcid":"https://orcid.org/0000-0001-6157-7629","contributorId":1810,"corporation":false,"usgs":true,"family":"Wild","given":"Emily","email":"ecwild@usgs.gov","middleInitial":"C.","affiliations":[{"id":5081,"text":"Libraries","active":false,"usgs":true}],"preferred":false,"id":240629,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":49925,"text":"ofr97368 - 1997 - Level II scour analysis for Bridge 38 (ANDOVT00110038) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont","interactions":[],"lastModifiedDate":"2013-12-20T14:53:21","indexId":"ofr97368","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":"97-368","title":"Level II scour analysis for Bridge 38 (ANDOVT00110038) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nANDOVT00110038 on State Route 11 crossing the Middle Branch Williams River, \nAndover, 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 \nsouth central Vermont. The 5.65-mi2\n drainage area is in a predominantly rural and forested \nbasin. Upstream and downstream of the study site banks and overbanks are forested.
\nIn the study area, the Middle Branch Williams River has an incised, sinuous channel with a \nslope of approximately 0.02 ft/ft, an average channel top width of 44 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 54.0 mm (0.177 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on September 5, 1996, indicated that the reach was stable.
\nThe State Route 11 crossing of the Middle Branch Williams River is a 33-ft-long, two-lane \nbridge consisting of one 31-foot concrete T-beam span (Vermont Agency of Transportation, \nwritten communication, March 29, 1995). The bridge is supported by vertical, concrete \nabutments with wingwalls. The channel is skewed approximately 55 degrees to the opening \nwhile the measured opening-skew-to-roadway is 45 degrees.
\nThere were no scour problems observed during the Level I assessment. Type-4 stone fill \n(less than 60 inches diameter) and type-3 stone fill (less than 48 inches diameter) was \npresent on the left bank upstream and right bank upstream respectively. Type-2 stone fill \n(less than 36 inches diameter) was present in the upstream left wing wall area. Additional \ndetails describing conditions at the site are included in the Level II Summary and \nAppendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). \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 1.8 to 3.4 ft. The worst-case \ncontraction scour occurred at the 500-year flow. Abutment scour ranged from 12.0 to 14.0 \nft. The worst-case abutment scour occurred at the 500-year flow at 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 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/ofr97368","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Striker, L.K., and Hammond, R.E., 1997, Level II scour analysis for Bridge 38 (ANDOVT00110038) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont: U.S. Geological Survey Open-File Report 97-368, iv, 50 p., https://doi.org/10.3133/ofr97368.","productDescription":"iv, 50 p.","numberOfPages":"55","costCenters":[],"links":[{"id":170457,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97368.PNG"},{"id":279757,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0368/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Andover","otherGeospatial":"Middle Branch Williams River","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":"4f4e4b17e4b07f02db6a62e1","contributors":{"authors":[{"text":"Striker, Lora K.","contributorId":41481,"corporation":false,"usgs":true,"family":"Striker","given":"Lora","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":240482,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hammond, Robert E.","contributorId":61862,"corporation":false,"usgs":true,"family":"Hammond","given":"Robert","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":240483,"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":49888,"text":"ofr97183 - 1997 - Level II scour analysis for Bridge 26 (PUTNTH00010026) on Town Highway 1, crossing Sacketts Brook, Putney, Vermont","interactions":[],"lastModifiedDate":"2014-01-07T10:05:39","indexId":"ofr97183","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":"97-183","title":"Level II scour analysis for Bridge 26 (PUTNTH00010026) on Town Highway 1, crossing Sacketts Brook, Putney, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nPUTNTH00010026 on Town Highway 1 crossing Sacketts Brook, Putney, 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 southern Vermont. The 10.1-mi2 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, Sacketts Brook has an incised, straight channel with a slope of \napproximately 0.01 ft/ft, an average channel top width of 35 ft and an average bank height \nof 5 ft. The channel bed material is predominantly cobble with a median grain size (D50) of \n68.3 mm (0.224 ft). The geomorphic assessment at the time of the Level I and Level II site \nvisit on August 20, 1996, indicated that the reach was stable.
\nThe Town Highway 1 crossing of Sacketts Brook is a 49-ft-long, two-lane bridge consisting\nof one 46-foot concrete T-beam span (Vermont Agency of Transportation, written\ncommunication, March 30, 1995). The bridge is supported by vertical, concrete abutments.\nThe channel is skewed approximately 35 degrees to the opening while the opening-skew-to-\nroadway is 45 degrees.
\nThe scour protection measure at the site was type-2 stone fill (less than 36 inches diameter) \nat the upstream end of the left abutment and along the entire base length of the right \nabutment. There was also a vertical stone wall along the upstream left bank. Additional \ndetails describing conditions at the site are included in the Level II Summary and \nAppendices D and E.
\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a \nhighway crossing is comprised of three components: 1) long-term streambed degradation; \n2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) \nand; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is \nthe sum of the three components. Equations are available to compute depths for contraction \nand local scour and a summary of the results of these computations follows.
\nContraction scour for modelled flows ranged from 0.0 to 2.7 ft. The worst-case contraction \nscour occurred at the 500-year discharge. Left abutment scour ranged from 7.9 to 9.9 ft. \nwith the worst-case occurring at the 100-year discharge. Right abutment scour ranged from \n12.6 to 17.0 ft. with the worst-case occurring 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/ofr97183","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., 1997, Level II scour analysis for Bridge 26 (PUTNTH00010026) on Town Highway 1, crossing Sacketts Brook, Putney, Vermont: U.S. Geological Survey Open-File Report 97-183, iv, 50 p., https://doi.org/10.3133/ofr97183.","productDescription":"iv, 50 p.","numberOfPages":"55","costCenters":[],"links":[{"id":170020,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97183.GIF"},{"id":279814,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0183/report.pdf"}],"scale":"25000","country":"United States","state":"Vermont","city":"Putney","otherGeospatial":"Sacketts Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,42.875 ], [ -72.75,43.125 ], [ -72.5,43.125 ], [ -72.5,42.875 ], [ -72.75,42.875 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8018","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240425,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":49887,"text":"ofr97182 - 1997 - Level II scour analysis for Bridge 4 (ARLITH00010004) on Town Highway 1, crossing Warm Brook, Arlington, Vermont","interactions":[],"lastModifiedDate":"2014-01-07T10:30:16","indexId":"ofr97182","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":"97-182","title":"Level II scour analysis for Bridge 4 (ARLITH00010004) on Town Highway 1, crossing Warm Brook, Arlington, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nARLITH00010004 on Town Highway 1 crossing Warm Brook, Arlington, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.
\nThe site is in the Taconic section of the New England physiographic province in \nsouthwestern Vermont. The 12.1-mi2\n drainage area consists of a predominantly rural and \nforested basin. In the vicinity of the study site, the surface cover is brush except for the \nupstream and downstream right banks which are covered by brush and grass.
\nIn the study area, Warm Brook has an incised, straight channel with a slope of \napproximately 0.003 ft/ft, an average channel top width of 19 ft and an average bank height \nof 1 ft. The channel bed material ranges from sand to cobble with a median grain size (D50) \nof 33.3 mm (0.109 ft). The geomorphic assessment at the time of the Level I and Level II \nsite visit on July 30, 1996, indicated that the reach was stable.
\nThe Town Highway 1 crossing of Warm Brook is a 49-ft-long, two-lane bridge consisting \nof one 44-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, January 30, 1996). The bridge is supported by vertical, concrete abutments \nwith wingwalls. The abutments have been placed on top of the previous stone abutments. \nThe channel is skewed approximately 0 degrees to the opening while the opening-skew-to-\nroadway is 20 degrees.
\nA scour hole approximately 1.0 ft deeper than the mean thalweg depth was observed mid-\nchannel in the upstream reach within 30 ft of the bridge. The only scour protection measure \nat the site was type-2 stone fill (less than 36 inches diameter) along the upstream left bank \napproach to the bridge. Additional details describing conditions at the site are included in \nthe Level II Summary and Appendices D and E.
\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a \nhighway crossing is comprised of three components: 1) long-term streambed degradation; \n2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) \nand; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is \nthe sum of the three components. Equations are available to compute depths for contraction \nand local scour and a summary of the results of these computations follows.
\nContraction scour for all modelled flows ranged from 0.0 to 1.7 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 8.3 to \n11.9 ft. The worst-case abutment scour also occurred at the 500-year discharge. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97182","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Olson, S.A., and Ivanoff, M.A., 1997, Level II scour analysis for Bridge 4 (ARLITH00010004) on Town Highway 1, crossing Warm Brook, Arlington, Vermont: U.S. Geological Survey Open-File Report 97-182, iv, 51 p., https://doi.org/10.3133/ofr97182.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":170173,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97182.GIF"},{"id":279815,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0182/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Arlington","otherGeospatial":"Warm Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -73.25,43.0 ], [ -73.25,43.125 ], [ -73.125,43.125 ], [ -73.125,43.0 ], [ -73.25,43.0 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a6221","contributors":{"authors":[{"text":"Olson, Scott A. 0000-0002-1064-2125 solson@usgs.gov","orcid":"https://orcid.org/0000-0002-1064-2125","contributorId":2059,"corporation":false,"usgs":true,"family":"Olson","given":"Scott","email":"solson@usgs.gov","middleInitial":"A.","affiliations":[{"id":405,"text":"NH/VT office of New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240423,"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":240424,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":67563,"text":"i2585 - 1997 - Digital shaded-relief image of Alaska","interactions":[],"lastModifiedDate":"2019-12-25T09:01:48","indexId":"i2585","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":320,"text":"IMAP","code":"I","active":false,"publicationSubtype":{"id":5}},"seriesNumber":"2585","title":"Digital shaded-relief image of Alaska","docAbstract":"One of the most spectacular physiographic images of the conterminous United States, and the first to have been produced digitally, is that by Thelin and Pike (USGS I-2206, 1991). The image is remarkable for its crispness of detail and for the natural appearance of the artificial land surface. Our goal has been to produce a shaded-relief image of Alaska that has the same look and feel as the Thelin and Pike image. The Alaskan image could have been produced at the same scale as its lower 48 counterpart (1:3,500,000). But by insetting the Aleutian Islands into the Gulf of Alaska, we were able to print the Alaska map at a larger scale (1:2,500,000) and about the same physical size as the Thelin and Pike image. Benefits of the 1:2,500,000 scale are (1) greater resolution of topographic features and (2) ease of reference to the U.S. Geological Survey (USGS) (1987) Alaska Map E and the statewide geologic map (Beikman, 1980), which are both 1:2,500,000 scale.
Manually drawn, shaded-relief images of Alaska's land surface have long been available (for example, Department of the Interior, 1909; Raisz, 1948). The topography depicted on these early maps is mainly schematic. Maps showing topographic contours were first available for the entire State in 1953 (USGS, 1:250,000) (J.H. Wittmann, USGS, written commun., 1996). The Alaska Map E was initially released in 1954 in both planimetric (revised in 1973 and 1987) and shaded-relief versions (revised in 1973, 1987, and 1996); topography depicted on the shaded-relief version is based on the 1:250,000-scale USGS topographic maps. Alaska Map E was later modified to include hypsometric tinting by Raven Maps and Images (1989, revised 1993) as copyrighted versions. Other shaded-relief images were produced for The National Geographic Magazine (LaGorce, 1956; 1:3,000,000) or drawn by Harrison (1970; 1:7,500,000) for The National Atlas of the United States. Recently, the State of Alaska digitally produced a shaded-relief image of Alaska at 1:2,500,000 scale (Alaska Department of Natural Resources, 1994), using the 1,000-m digital elevation data set referred to below.
An important difference between our image and these previous ones is the method of reproduction: like the Thelin and Pike (1991) image, our image is a composite of halftone images that yields sharp resolution and preserves contrast. Indeed, the first impression of many viewers is that the Alaskan image and the Thelin and Pike image are composites of satellite-generated photographs rather than an artificial rendering of a digital elevation model.
A shaded-relief image represents landforms in a natural fashion; that is, a viewer perceives the image as a rendering of reality. Thus a shaded-relief image is intrinsically appealing, especially in areas of spectacular relief. In addition, even subtle physiographic features that reflect geologic structures or the type of bedrock are visible. To our knowledge, some of these Alaskan features have not been depicted before and so the image should provide earth scientists with a new \"look\" at fundamental geologic features of Alaska.
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J.","affiliations":[],"preferred":false,"id":276710,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Plafker, George","contributorId":3920,"corporation":false,"usgs":false,"family":"Plafker","given":"George","email":"","affiliations":[],"preferred":false,"id":276706,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Till, A.B.","contributorId":37755,"corporation":false,"usgs":true,"family":"Till","given":"A.B.","email":"","affiliations":[],"preferred":false,"id":276709,"contributorType":{"id":1,"text":"Authors"},"rank":9}]}} ,{"id":49994,"text":"ofr97754 - 1997 - Level II scour analysis for Bridge 21 (MIDBTH00230021) on Town Highway 23, crossing the Middlebury River, Middlebury, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T13:20:16","indexId":"ofr97754","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":"97-754","title":"Level II scour analysis for Bridge 21 (MIDBTH00230021) on Town Highway 23, crossing the Middlebury River, Middlebury, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nMIDBTH00230021 on Town Highway 23 crossing the Middlebury River, Middlebury, \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 \nwest-central Vermont. The 44.8-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is suburban consisting of single \nhouses, each with a lawn, trees, and shrubs on all of the overbank areas bordering the river.
\nIn the study area, the Middlebury River has a straight channel with a slope of approximately \n0.02 ft/ft, an average channel top width of 87 ft and an average channel depth of 11 ft. The \nchannel bed material ranges from gravel to boulders with a median grain size (D50) of 152 \nmm (0.498 ft). The geomorphic assessment at the time of the Level I and Level II site visit \non June 18, 1996, indicated that the reach was stable.
\nThe Town Highway 23 crossing of the Middlebury River is a 52-ft-long, two-lane bridge \nconsisting of one 49-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, December 14, 1995). The opening length of the structure parallel to the \nbridge face is 42.3 feet. The bridge is supported by vertical, concrete abutments with \nwingwalls at each end of the left abutment only. The channel is skewed approximately 10 \ndegrees to the opening. The opening-skew-to-roadway from the VTAOT records is zero \ndegrees while 5 degrees was computed from surveyed points.
\nA scour hole 1.0 foot deeper than the mean thalweg depth was observed in the channel at \nthe upstream bridge face during the Level I assessment. The scour protection measure at the \nsite was type-2 stone fill (less than 36 inches diameter) on the upstream and downstream \nbanks and the upstream and downstream left wingwalls. Additional details describing \nconditions at the site are included in the Level II Summary and Appendices D and E.
\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-\nyear discharges. In addition, the incipient roadway-overtopping discharge is determined and \nanalyzed as another potential worst-case scour scenario. Total scour at a highway crossing \nis comprised of three components: 1) long-term streambed degradation; 2) contraction \nscour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local \nscour (caused by accelerated flow around piers and abutments). Total scour is the sum of \nthe three components. Equations are available to compute depths for contraction and local \nscour and a summary of the results of these computations follows.
\nContraction scour for all modelled flows ranged from 1.2 to 1.8 feet. The worst-case \ncontraction scour occurred at the incipient overtopping discharge, which is less than the \n500-year discharge. Abutment scour ranged from 17.7 to 23.7 feet. 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.
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