This report provides the results of a detailed Level II analysis of scour potential at structure TUNBTH00450033 on Town Highway 45 crossing the First Branch White River, Tunbridge, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.
The site is in the New England Upland section of the New England physiographic province in central Vermont. The 86.4-mi 2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture upstream and downstream of the bridge, while woody vegetation sparsely covers the immediate banks.
In the study area, the First Branch White River has an incised, sinuous channel with a slope of approximately 0.003 ft/ft, an average channel top width of 68 ft and an average bank height of 7 ft. The channel bed material ranges from sand to gravel with a median grain size (D50) of 27.1 mm (0.089 ft). The geomorphic assessment at the time of the Level I and Level II site visit on October 18, 1995, indicated that the reach was laterally unstable due to a cut-bank present on the upstream right bank and a wide channel bar in the upstream reach.
The Town Highway 45 crossing of the First Branch White River is a 67-ft-long, one-lane bridge consisting of one 54-foot timber thru-truss span (Vermont Agency of Transportation, written communication, March 23, 1995). The opening length of the structure parallel to the bridge face is 53.5 ft. The bridge is supported on the right by a vertical, concrete abutment with an upstream wingwall, and on the left by a vertical, stone abutment. The channel is skewed approximately 20 degrees to the opening while the computed opening-skew-to-roadway is 10 degrees.
A scour hole 1.5 ft deeper than the mean thalweg depth was observed along the right abutment during the Level I assessment. Scour countermeasures at the site include type-1 stone fill (less than 12 inches diameter) along the upstream right wingwall, type-2 stone fill (less than 36 inches diameter) along the right abutment, and type-3 stone fill (less than 48 inches diameter) 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 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 3.0 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 12.8 to 31.0 ft. Right abutment scour ranged from 9.8 to 19.0 ft. The worst-case left and right abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in Tables 1 and 2. A cross-section of the scour computed at the bridge is presented in Figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.
It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/ofr97803","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and the Federal Highway Administration","usgsCitation":"Wild, E., and Severance, T., 1997, Level II scour analysis for Bridge 33 (TUNBTH00450033) on Town Highway 45, crossing the First Branch White River, Tunbridge, Vermont: U.S. Geological Survey Open-File Report 97-803, iv, 52 p., https://doi.org/10.3133/ofr97803.","productDescription":"iv, 52 p.","additionalOnlineFiles":"N","costCenters":[],"links":[{"id":161572,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97803.JPG"},{"id":279659,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0803/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Tunbridge","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -7.035,43.01527777777778 ], [ -7.035,0.0011111111111111111 ], [ -72.5,0.0011111111111111111 ], [ -72.5,43.01527777777778 ], [ -7.035,43.01527777777778 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b18e4b07f02db6a6881","contributors":{"authors":[{"text":"Wild, E.C. 0000-0001-6157-7629","orcid":"https://orcid.org/0000-0001-6157-7629","contributorId":71227,"corporation":false,"usgs":true,"family":"Wild","given":"E.C.","affiliations":[{"id":5081,"text":"Libraries","active":false,"usgs":true}],"preferred":false,"id":240657,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Severance, Timothy","contributorId":104927,"corporation":false,"usgs":true,"family":"Severance","given":"Timothy","email":"","affiliations":[],"preferred":false,"id":240658,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50027,"text":"ofr97805 - 1997 - Level II scour analysis for Bridge 16 (GROTTH00170016) on Town Highway 17, crossing the Wells River, Groton, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T15:08:07","indexId":"ofr97805","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":"97-805","title":"Level II scour analysis for Bridge 16 (GROTTH00170016) on Town Highway 17, crossing the Wells River, Groton, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nGROTTH00170016 on Town Highway 17 crossing the Wells River, Groton, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.\nThe site is in the New England Upland section of the New England physiographic province \nin eastern Vermont. The 43.4-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, while the left bank downstream is forested. \nIn the study area, the Wells River has an incised, straight channel with a slope of \napproximately 0.003 ft/ft, an average channel top width of 57 ft and an average bank height \nof 4 ft. The channel bed material ranges from sand to boulder with a median grain size (D50) \nof 77.8 mm (0.255 ft). The geomorphic assessment at the time of the Level I and Level II \nsite visit on August 29, 1995, indicated that the reach was stable.\nThe Town Highway 17 crossing of the Wells River is a 43-ft-long, one-lane bridge \nconsisting of one 41-foot steel-beam span with a concrete deck (Vermont Agency of \nTransportation, written communication, March 24, 1995). The opening length of the \nstructure parallel to the bridge face is 39.4 ft. The bridge is supported by vertical, concrete \nabutments. The channel is skewed approximately 0 degrees and the opening-skew-toroadway is also zero degrees. \nA scour hole 1.7 ft deeper than the mean thalweg depth was observed from 30 ft upstream \nto 70 ft downstream in mid-channel during the Level I assessment. Scour protection \nmeasures at the site included: type-3 stone fill (less than 48 inches diameter) along the left \nand right bank upstream, and along the left and right bank downstream. The protection \nalong the banks begins in the road embankment areas where the wingwalls would be \nlocated. Additional details describing conditions at the site are included in the Level II \nSummary and Appendices D and E.\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) \nfor the 100- and 500-year discharges. In addition, the incipient roadway-overtopping \ndischarge is determined and analyzed as another potential worst-case scour scenario. Total \nscour at a highway crossing is comprised of three components: 1) long-term streambed \ndegradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow \narea at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.\nContraction scour for all modelled flows was 0 ft. Abutment scour ranged from 7.6 to 8.4 ft \nat the left abutment and from 9.9 to 14.8 ft at the right abutment. The worst-case abutment \nscour occurred at the 500-year discharge. Additional information on scour depths and \ndepths to armoring are included in the section titled “Scour Results”. Scoured-streambed \nelevations, based on the calculated scour depths, are presented in tables 1 and 2. A crosssection of the scour computed at the bridge is presented in figure 8. Scour depths were \ncalculated assuming an infinite depth of erosive material and a homogeneous particle-size \ndistribution. \nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97805","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and the Federal Highway Administration","usgsCitation":"Striker, L., and Ivanoff, M., 1997, Level II scour analysis for Bridge 16 (GROTTH00170016) on Town Highway 17, crossing the Wells River, Groton, Vermont: U.S. Geological Survey Open-File Report 97-805, 51 p., https://doi.org/10.3133/ofr97805.","productDescription":"51 p.","additionalOnlineFiles":"N","costCenters":[],"links":[{"id":161675,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97805.JPG"},{"id":279657,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0805/report.pdf"}],"projection":"24000","country":"United States","state":"Vermont","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.250,44.125 ], [ -72.250,44.250 ], [ -72.125,44.250 ], [ -72.125,44.125 ], [ -72.250,44.125 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8373","contributors":{"authors":[{"text":"Striker, L.K.","contributorId":55872,"corporation":false,"usgs":true,"family":"Striker","given":"L.K.","email":"","affiliations":[],"preferred":false,"id":240662,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Ivanoff, M.A.","contributorId":45758,"corporation":false,"usgs":true,"family":"Ivanoff","given":"M.A.","email":"","affiliations":[],"preferred":false,"id":240661,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50029,"text":"ofr97808 - 1997 - Level II scour analysis for Bridge 5 (WOLCTH00150005) on Town Highway 15, crossing the Wild Branch Lamoille River, Wolcott, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T13:13:10","indexId":"ofr97808","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":"97-808","title":"Level II scour analysis for Bridge 5 (WOLCTH00150005) on Town Highway 15, crossing the Wild Branch Lamoille River, Wolcott, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure WOLCTH00150005 on Town Highway 15 crossing the Wild Branch Lamoille River, Wolcott, 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.
During the August 1995 and July 1997 flood events, the left roadway was overtopped. Although there was loss of stone fill along the right abutment, the structure withstood both events.
The site is in the Green Mountain section of the New England physiographic province in north- central Vermont. The 38.3-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture upstream and downstream of the bridge, while the immediate banks have dense woody vegetation.
In the study area, the Wild Branch Lamoille River has an incised, sinuous channel with a slope of approximately 0.006 ft/ft, an average channel top width of 98 ft and an average bank height of 5 ft. The channel bed material ranges from gravel to bedrock with a median grain size (D50) of 89.1 mm (0.292 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 17, 1996, indicated that the reach was stable.
The Town Highway 15 crossing of the Wild Branch Lamoille River is a 46-ft-long, two-lane bridge consisting of a 43-foot prestressed concrete box-beam span (Vermont Agency of Transportation, written communication, October 13, 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 10 degrees to the opening while the opening- skew-to-roadway is zero degrees.
A scour hole 2.0 ft deeper than the mean thalweg depth was observed near the bridge along the left side of the channel during the Level I assessment. Scour countermeasures at the site consists of type-1 stone fill (less than 12 inches diameter) along the upstream left bank and along the left and right downstream banks, type-2 stone fill (less than 36 inches diameter) along the downstream left and right wingwalls, type-3 stone fill (less than 48 inches diameter) along the upstream left wingwall and the right abutment, and type-4 stone fill (less than 60 inches diameter) along the upstream right wingwall and the left abutment. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.
Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995) for the 100- and 500-year discharges. 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 was zero ft. Left abutment scour ranged from 7.9 to 23.3 ft. The worst-case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 21.5 to 22.8 ft. The worst-case right abutment scour occurred at the incipient roadway-overtopping discharge. Additional in formation 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/ofr97808","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., 1997, Level II scour analysis for Bridge 5 (WOLCTH00150005) on Town Highway 15, crossing the Wild Branch Lamoille River, Wolcott, Vermont: U.S. Geological Survey Open-File Report 97-808, iv, 50 p., https://doi.org/10.3133/ofr97808.","productDescription":"iv, 50 p.","numberOfPages":"55","additionalOnlineFiles":"N","costCenters":[],"links":[{"id":162124,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97808.GIF"},{"id":279655,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0808/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Wolcott","otherGeospatial":"Wild Branch Lamoille River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.750,43.500 ], [ -72.750,43.625 ], [ -72.625,43.625 ], [ -72.625,43.500 ], [ -72.750,43.500 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a5d90","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":240665,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":50038,"text":"ofr97207 - 1997 - Level II scour analysis for Bridge 27 (BRIGVT001140027) on State Route 114, crossing Pherrins River, Brighton, Vermont","interactions":[],"lastModifiedDate":"2013-12-02T10:07:54","indexId":"ofr97207","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":"97-207","title":"Level II scour analysis for Bridge 27 (BRIGVT001140027) on State Route 114, crossing Pherrins River, Brighton, Vermont","language":"ENGLISH","doi":"10.3133/ofr97207","usgsCitation":"Boehmler, E.M., 1997, Level II scour analysis for Bridge 27 (BRIGVT001140027) on State Route 114, crossing Pherrins River, Brighton, Vermont: U.S. Geological Survey Open-File Report 97-207, 49 p., https://doi.org/10.3133/ofr97207.","productDescription":"49 p.","costCenters":[],"links":[{"id":175956,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":280089,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0207/report.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a7fde","contributors":{"authors":[{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240680,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":50040,"text":"ofr97392 - 1997 - Level II scour analysis for Bridge 13 (EDENTH00170013) on Town Highway 17, crossing the Gihon River, Eden, Vermont","interactions":[],"lastModifiedDate":"2013-12-02T10:08:28","indexId":"ofr97392","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":"97-392","title":"Level II scour analysis for Bridge 13 (EDENTH00170013) on Town Highway 17, crossing the Gihon River, Eden, Vermont","language":"ENGLISH","doi":"10.3133/ofr97392","usgsCitation":"Ivanoff, M., 1997, Level II scour analysis for Bridge 13 (EDENTH00170013) on Town Highway 17, crossing the Gihon River, Eden, Vermont: U.S. Geological Survey Open-File Report 97-392, 50 p., https://doi.org/10.3133/ofr97392.","productDescription":"50 p.","costCenters":[],"links":[{"id":175958,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":280090,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0392/report.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a838f","contributors":{"authors":[{"text":"Ivanoff, M.A.","contributorId":45758,"corporation":false,"usgs":true,"family":"Ivanoff","given":"M.A.","email":"","affiliations":[],"preferred":false,"id":240683,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":50041,"text":"ofr97824 - 1997 - Level II scour analysis for Bridge 11 (STAMVT01000011) on State Route 11, crossing Crazy John Stream, Stamford, Vermont","interactions":[],"lastModifiedDate":"2013-12-02T10:09:45","indexId":"ofr97824","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":"97-824","title":"Level II scour analysis for Bridge 11 (STAMVT01000011) on State Route 11, crossing Crazy John Stream, Stamford, Vermont","language":"ENGLISH","doi":"10.3133/ofr97824","usgsCitation":"Ivanoff, M., and Degnan, J., 1997, Level II scour analysis for Bridge 11 (STAMVT01000011) on State Route 11, crossing Crazy John Stream, Stamford, Vermont: U.S. Geological Survey Open-File Report 97-824, 50 p., https://doi.org/10.3133/ofr97824.","productDescription":"50 p.","costCenters":[],"links":[{"id":175959,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":280092,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0824/report.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a840b","contributors":{"authors":[{"text":"Ivanoff, M.A.","contributorId":45758,"corporation":false,"usgs":true,"family":"Ivanoff","given":"M.A.","email":"","affiliations":[],"preferred":false,"id":240685,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Degnan, J.R.","contributorId":18423,"corporation":false,"usgs":true,"family":"Degnan","given":"J.R.","email":"","affiliations":[],"preferred":false,"id":240684,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50042,"text":"ofr97822 - 1997 - Level II scour analysis for Bridge 22 (TOPSTH00490022) on Town Highway 49, crossing Waits River, Topsham, Vermont","interactions":[],"lastModifiedDate":"2013-12-02T10:11:27","indexId":"ofr97822","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":"97-822","title":"Level II scour analysis for Bridge 22 (TOPSTH00490022) on Town Highway 49, crossing Waits River, Topsham, Vermont","language":"ENGLISH","doi":"10.3133/ofr97822","usgsCitation":"Striker, L., and Degnan, J., 1997, Level II scour analysis for Bridge 22 (TOPSTH00490022) on Town Highway 49, crossing Waits River, Topsham, Vermont: U.S. Geological Survey Open-File Report 97-822, 50 p., https://doi.org/10.3133/ofr97822.","productDescription":"50 p.","costCenters":[],"links":[{"id":175960,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":280094,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0822/report.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8104","contributors":{"authors":[{"text":"Striker, L.K.","contributorId":55872,"corporation":false,"usgs":true,"family":"Striker","given":"L.K.","email":"","affiliations":[],"preferred":false,"id":240687,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Degnan, J.R.","contributorId":18423,"corporation":false,"usgs":true,"family":"Degnan","given":"J.R.","email":"","affiliations":[],"preferred":false,"id":240686,"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":50139,"text":"ofr97130 - 1997 - Seismic-Hazard Maps for California, Nevada, and Western Arizona/Utah","interactions":[],"lastModifiedDate":"2012-02-10T00:10:10","indexId":"ofr97130","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":"97-130","title":"Seismic-Hazard Maps for California, Nevada, and Western Arizona/Utah","language":"ENGLISH","publisher":"Geological Survey (U.S.)","doi":"10.3133/ofr97130","usgsCitation":"Frankel, A.D., Mueller, C., Barnhard, T., Perkins, D., Leyendecker, E.V., Dickman, N., Hanson, S., and Hopper, M., 1997, Seismic-Hazard Maps for California, Nevada, and Western Arizona/Utah: U.S. Geological Survey Open-File Report 97-130, 12 maps; Sheets numbered A-L with individual subtitles, https://doi.org/10.3133/ofr97130.","productDescription":"12 maps; Sheets numbered A-L with individual subtitles","costCenters":[{"id":595,"text":"U.S. Geological Survey","active":false,"usgs":true}],"links":[{"id":175283,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":4324,"rank":200,"type":{"id":11,"text":"Document"},"url":"https://geo-nsdi.er.usgs.gov/metadata/open-file/97-131/metadata.faq.html","linkFileType":{"id":5,"text":"html"}}],"scale":"2000000","projection":"Albers Equal Area Conic","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -125,32 ], [ -125,43 ], [ -111,43 ], [ -111,32 ], [ -125,32 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a9be4b07f02db65e144","contributors":{"authors":[{"text":"Frankel, Arthur D. 0000-0001-9119-6106 afrankel@usgs.gov","orcid":"https://orcid.org/0000-0001-9119-6106","contributorId":1363,"corporation":false,"usgs":true,"family":"Frankel","given":"Arthur","email":"afrankel@usgs.gov","middleInitial":"D.","affiliations":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"preferred":false,"id":240823,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Mueller, C.","contributorId":40201,"corporation":false,"usgs":true,"family":"Mueller","given":"C.","email":"","affiliations":[],"preferred":false,"id":240827,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Barnhard, T.","contributorId":63458,"corporation":false,"usgs":true,"family":"Barnhard","given":"T.","email":"","affiliations":[],"preferred":false,"id":240828,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Perkins, D.","contributorId":83589,"corporation":false,"usgs":true,"family":"Perkins","given":"D.","affiliations":[],"preferred":false,"id":240829,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Leyendecker, E. V.","contributorId":87162,"corporation":false,"usgs":true,"family":"Leyendecker","given":"E.","email":"","middleInitial":"V.","affiliations":[],"preferred":false,"id":240830,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Dickman, N.","contributorId":17279,"corporation":false,"usgs":true,"family":"Dickman","given":"N.","email":"","affiliations":[],"preferred":false,"id":240824,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Hanson, S.","contributorId":35781,"corporation":false,"usgs":true,"family":"Hanson","given":"S.","affiliations":[],"preferred":false,"id":240826,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Hopper, M.","contributorId":25999,"corporation":false,"usgs":true,"family":"Hopper","given":"M.","affiliations":[],"preferred":false,"id":240825,"contributorType":{"id":1,"text":"Authors"},"rank":8}]}} ,{"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":49913,"text":"ofr97341 - 1997 - Level II scour analysis for Bridge 2 (BENNCYPARK0002) on Park Street, crossing Furnace Brook, Bennington, Vermont","interactions":[],"lastModifiedDate":"2014-01-05T13:22:53","indexId":"ofr97341","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-341","title":"Level II scour analysis for Bridge 2 (BENNCYPARK0002) on Park Street, crossing Furnace Brook, Bennington, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nBENNCYPARK0002 on the Park Street crossing of Furnace Brook, Bennington, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.
\nThe site is in the Green Mountain section of the New England physiographic province in \nsouthwestern Vermont. The 12.8-mi2\n drainage area is a predominantly rural and forested \nbasin. The bridge site is located within an urban setting in the Town of Bennington with \nbuildings, homes, lawns, and pavement on the overbanks.
\nIn the study area, Furnace Brook has a mildly sinuous channel located on a delta and has a \nslope of approximately 0.01 ft/ft, an average channel top width of 35 ft and an average bank \nheight of 4 ft. The predominant channel bed materials are gravel and cobble with a median \ngrain size (D50) of 58.4 mm (0.192 ft). The geomorphic assessment at the time of the Level \nI and Level II site visit on August 6, 1996, indicated that the reach was unstable. However, \nin the immediate vicinity of the bridge the reach has been stabilized with bank protection. \nUpstream of the protection, there is bank cutting and channel scour.
\nThe Park Street crossing of Furnace Brook is a 29-ft-long, two-lane bridge consisting of one \n26-foot concrete span (Vermont Agency of Transportation, written communication, \nDecember 14, 1995). The width of the bridge opening parallel to the downstream bridge \nface is 25.3 feet. The bridge is supported by vertical, concrete abutments with no wingwalls. \nThe upstream channel is skewed approximately 45 degrees to the opening while the \nopening-skew-to-roadway is 10 degrees.
\nScour countermeasures at the site include type-2 stone fill (less than 36 inches diameter) on \nthe right banks upstream and downstream of the bridge and type-3 stone fill (less than 48 \ninches diameter) on the upstream left bank. Additional details describing conditions at the \nsite are included in the Level II Summary and Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). \nTotal scour at a highway crossing is comprised of three components: 1) long-term \nstreambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction \nin flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.
\nThere was no contraction scour computed for any of the modelled flows. Computed left \nabutment scour ranged from 2.5 to 5.6 ft. with the worst-case scour occurring at the 500-\nyear discharge. Computed right abutment scour ranged from 5.6 to 8.4 ft. with the worst-\ncase scour also occurring at the 100-year discharge. Additional information on scour depths \nand depths to armoring are included in the section titled “Scour Results”. Scoured-\nstreambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. \nA cross-section of the scour computed at the bridge is presented in figure 8. Scour depths \nwere calculated assuming an infinite depth of erosive material and a homogeneous particle-\nsize distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97341","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Olson, S.A., 1997, Level II scour analysis for Bridge 2 (BENNCYPARK0002) on Park Street, crossing Furnace Brook, Bennington, Vermont: U.S. Geological Survey Open-File Report 97-341, iv, 51 p., https://doi.org/10.3133/ofr97341.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":169722,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97341.GIF"},{"id":279772,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0341/report.pdf"}],"country":"United States","state":"Vermont","city":"Bennington","otherGeospatial":"Furnace Brook","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a81a3","contributors":{"authors":[{"text":"Olson, Scott A. 0000-0002-1064-2125 solson@usgs.gov","orcid":"https://orcid.org/0000-0002-1064-2125","contributorId":2059,"corporation":false,"usgs":true,"family":"Olson","given":"Scott","email":"solson@usgs.gov","middleInitial":"A.","affiliations":[{"id":405,"text":"NH/VT office of New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240467,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":22010,"text":"ofr97279 - 1997 - Palynostratigraphy of Cretaceous and Quaternary strata in the Robins Point corehole, Aberdeen Proving Ground, Harford County, Maryland","interactions":[],"lastModifiedDate":"2020-10-08T16:48:47.922311","indexId":"ofr97279","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":"97-279","title":"Palynostratigraphy of Cretaceous and Quaternary strata in the Robins Point corehole, Aberdeen Proving Ground, Harford County, Maryland","docAbstract":"No abstract available.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/ofr97279","issn":"0094-9140","usgsCitation":"Frederiksen, N.O., Powars, D.S., Hoffmeister, A.P., and Sheehan, T.P., 1997, Palynostratigraphy of Cretaceous and Quaternary strata in the Robins Point corehole, Aberdeen Proving Ground, Harford County, Maryland: U.S. Geological Survey Open-File Report 97-279, 31 p., https://doi.org/10.3133/ofr97279.","productDescription":"31 p.","costCenters":[],"links":[{"id":379241,"rank":2,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0279/report.pdf","linkFileType":{"id":1,"text":"pdf"}},{"id":153263,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/of/1997/0279/report-thumb.jpg"}],"country":"United States","state":"Harford County","otherGeospatial":"Aberdeen Proving Ground","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -76.36749999999999,39.266666666666666 ], [ -76.36749999999999,39.5 ], [ -76.11749999999999,39.5 ], [ -76.11749999999999,39.266666666666666 ], [ -76.36749999999999,39.266666666666666 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4ae3e4b07f02db689450","contributors":{"authors":[{"text":"Frederiksen, Norman O.","contributorId":50880,"corporation":false,"usgs":true,"family":"Frederiksen","given":"Norman","email":"","middleInitial":"O.","affiliations":[],"preferred":false,"id":186671,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Powars, David S. 0000-0002-6787-8964 dspowars@usgs.gov","orcid":"https://orcid.org/0000-0002-6787-8964","contributorId":1181,"corporation":false,"usgs":true,"family":"Powars","given":"David","email":"dspowars@usgs.gov","middleInitial":"S.","affiliations":[{"id":243,"text":"Eastern Geology and Paleoclimate Science Center","active":true,"usgs":true},{"id":40020,"text":"Florence Bascom Geoscience Center","active":true,"usgs":true}],"preferred":true,"id":186668,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Hoffmeister, Alan P.","contributorId":46558,"corporation":false,"usgs":true,"family":"Hoffmeister","given":"Alan","email":"","middleInitial":"P.","affiliations":[],"preferred":false,"id":186670,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Sheehan, Thomas P. tsheehan@usgs.gov","contributorId":4277,"corporation":false,"usgs":true,"family":"Sheehan","given":"Thomas","email":"tsheehan@usgs.gov","middleInitial":"P.","affiliations":[],"preferred":true,"id":186669,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":49978,"text":"ofr97653 - 1997 - Level II scour analysis for Bridge 25 (REDSTH00360025) on Town Highway 36, crossing the West Branch Deerfield River, Readsboro, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T16:16:53","indexId":"ofr97653","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":330,"text":"Open-File Report","code":"OFR","onlineIssn":"2331-1258","printIssn":"0196-1497","active":true,"publicationSubtype":{"id":5}},"seriesNumber":"97-653","title":"Level II scour analysis for Bridge 25 (REDSTH00360025) on Town Highway 36, crossing the West Branch Deerfield River, Readsboro, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nREDSTH00360025 on Town Highway 36 crossing the West Branch Deerfield River, \nReadsboro, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the \nsite, including a quantitative analysis of stream stability and scour (U.S. Department of \nTransportation, 1993). Results of a Level I scour investigation also are included in \nAppendix E of this report. A Level I investigation provides a qualitative geomorphic \ncharacterization of the study site. Information on the bridge, gleaned from Vermont Agency \nof Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II \nanalyses and is found in Appendix D.
\nThe site is in the Green Mountain section of the New England physiographic province in \nsouth-central Vermont. The 14.5-mi2\n drainage area is in a predominantly rural and forested \nbasin. In the vicinity of the study site, the surface cover is pasture on the upstream right \nbank and forest on the upstream left bank. The surface cover on the downstream right and \nleft banks is primarily grass, shrubs and brush.
\nIn the study area, the West Branch Deerfield River has an incised, sinuous channel with a \nslope of approximately 0.02 ft/ft, an average channel top width of 65 ft and an average bank \nheight of 4 ft. The channel bed material ranges from gravel to boulders, with a median grain \nsize (D50) of 117 mm (0.383 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on August 1, 1996, indicated that the reach was stable.
\nThe Town Highway 36 crossing of the West Branch Deerfield River is a 59-ft-long, two-lane bridge consisting of one 57-foot concrete T-beam span (Vermont Agency of \nTransportation, written communication, September 28, 1995). The opening length of the \nstructure parallel to the bridge face is 54 ft. The bridge is supported by vertical, concrete \nabutments with wingwalls. The channel is skewed approximately 50 degrees to the opening \nwhile the opening-skew-to-roadway is 30 degrees.
\nDuring the Level I assessment, a scour hole approximately 2 ft deeper than the mean \nthalweg depth was observed along the upstream right wingwall and a scour hole \napproximately 1 ft deeper than the mean thalweg depth was observed along the downstream \nleft wingwall. The scour protection measure at the site was type-2 stone fill (less than 36 \ninches diameter) at the downstream end of the downstream left wingwall, at the upstream \nend of the upstream right wingwall, at the downstream end of the right abutment, along the \nentire base length of the downstream right wingwall, along the upstream right bank and \nalong the downstream left bank. A stone wall was noted along the upstream left bank. \nAdditional details describing conditions at the site are included in the Level II Summary \nand Appendices D and E.
\nScour depths and recommended rock rip-rap sizes were computed using the general \nguidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). \nTotal scour at a highway crossing is comprised of three components: 1) long-term \nstreambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction \nin flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.
\nContraction scour for all modelled flows ranged from 0.0 to 0.6 ft. The worst-case \ncontraction scour occurred at the incipient-overtopping discharge. Abutment scour ranged \nfrom 15.1 to 16.3 ft along the left abutment and from 7.4 to 9.2 ft along the right abutment. \nThe worst-case abutment scour occurred at the incipient-overtopping and 500-year \ndischarges for the left abutment and at the 500-year discharge for the right abutment. \nAdditional information on scour depths and depths to armoring are included in the section \ntitled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, \nare presented in \ntables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. \nScour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution.
\nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr97653","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Flynn, R.H., and Burns, R.L., 1997, Level II scour analysis for Bridge 25 (REDSTH00360025) on Town Highway 36, crossing the West Branch Deerfield River, Readsboro, Vermont: U.S. Geological Survey Open-File Report 97-653, iv, 54 p., https://doi.org/10.3133/ofr97653.","productDescription":"iv, 54 p.","numberOfPages":"59","costCenters":[],"links":[{"id":175372,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97653.GIF"},{"id":279700,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0653/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Readsboro","otherGeospatial":"Deerfield River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -73.125,42.75 ], [ -73.125,42.875 ], [ -72.875,42.875 ], [ -72.875,42.75 ], [ -73.125,42.75 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a801d","contributors":{"authors":[{"text":"Flynn, Robert H. rflynn@usgs.gov","contributorId":2137,"corporation":false,"usgs":true,"family":"Flynn","given":"Robert","email":"rflynn@usgs.gov","middleInitial":"H.","affiliations":[{"id":405,"text":"NH/VT office of New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240571,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240572,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50002,"text":"ofr97767 - 1997 - Level II scour analysis for Bridge 31 (JERITH00350031) on Town Highway 35, crossing Mill Brook, Jericho, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T13:31:00","indexId":"ofr97767","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":"97-767","title":"Level II scour analysis for Bridge 31 (JERITH00350031) on Town Highway 35, crossing Mill Brook, Jericho, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure JERITH00350031 on Town Highway 35 crossing Mill Brook, Jericho, Vermont (figures 1– 8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gathered from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.
The site is in the Green Mountain section of the New England physiographic province and the Champlain section of the St. Lawrence physiographic province in northwestern Vermont. The 15.7-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest upstream of the bridge. The downstream left overbank is pasture. The downstream right overbank is brushland.
In the study area, the Mill Brook has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 117 ft and an average bank height of 11 ft. The channel bed material ranges from gravel to boulders with a median grain size (D50) of 81.1 mm (0.266 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 3, 1996, indicated that the reach was laterally unstable.
The Town Highway 35 crossing of the Mill Brook is a 53-ft-long, one-lane bridge consisting of a 50-foot steel-beam span with a wooden deck (Vermont Agency of Transportation, written communication, November 30, 1995). The opening length of the structure parallel to the bridge face is 48 ft. The bridge is supported by a vertical, concrete abutment with wingwalls on the left. On the right, the abutment and wingwalls are laid-up stone with a concrete cap. The channel is not skewed to the opening. The roadway is skewed 10 degrees to the opening.
A scour hole 1.5 ft deeper than the mean thalweg depth was observed along the left abutment during the Level I assessment. Scour countermeasures at the site were type-2 stone fill (less than 36 inches diameter) at the upstream and downstream left wingwalls, the upstream and downsteam left channel banks, and the downstream left road embankment. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.
Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). In addition, the incipient roadway-overtopping discharge is analyzed since it has the potential of being the worst-case scour scenario. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for all modelled flows ranged from 0.4 to 1.3 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 9.9 to 12.4 ft. Right abutment scour ranged from 13.8 to 17.8 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/ofr97767","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., 1997, Level II scour analysis for Bridge 31 (JERITH00350031) on Town Highway 35, crossing Mill Brook, Jericho, Vermont: U.S. Geological Survey Open-File Report 97-767, iv, 52 p., https://doi.org/10.3133/ofr97767.","productDescription":"iv, 52 p.","numberOfPages":"57","costCenters":[],"links":[{"id":176343,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97767.PNG"},{"id":279676,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0767/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Jericho","otherGeospatial":"Mill Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -73.125,44.375 ], [ -73.125,44.5 ], [ -73.0,44.5 ], [ -73.0,44.375 ], [ -73.125,44.375 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a653e","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":240615,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":49926,"text":"ofr97369 - 1997 - Level II scour analysis for Bridge 10 (CHESTH00030010) on Town Highway 3 (VT 35), crossing the South Branch of Williams River, Chester, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T15:10:28","indexId":"ofr97369","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":"97-369","title":"Level II scour analysis for Bridge 10 (CHESTH00030010) on Town Highway 3 (VT 35), crossing the South Branch of Williams River, Chester, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure CHESTH00030010 on Town Highway 3 (VT 35) crossing the South Branch Williams River, Chester, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of a Level I scour investigation also are included in Appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in Appendix D.
The site is in the New England Upland section of the New England physiographic province in southeastern Vermont. The 9.44-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest.
In the study area, the South Branch Williams River has an incised, sinuous channel with a slope of approximately 0.03 ft/ft, an average channel top width of 67 ft and an average bank height of 5 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 69.0 mm (0.226 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 26-27, 1996, indicated that the reach was stable.
The Town Highway 3 (VT 35) crossing of the South Branch Williams River is a 69-foot-long, two-lane bridge consisting of one 67-foot steel-stringer span with a concrete deck (Vermont Agency of Transportation, written communication, August 23, 1994). The opening length of the structure parallel to the bridge face is 64.5 ft. The bridge is supported by vertical, concrete abutments with spill-through embankments. The channel is skewed approximately 50 degrees to the opening while the opening-skew-to-roadway is 30 degrees.
The scour protection (spill-through abutments) measured at the site was type-3 stone fill (less than 48 inches diameter) extending the entire base length and around the ends of the left and right abutments. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.
Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for modelled flows ranged from 0.8 to 3.8 ft. The worst-case contraction scour occurred at the incipient roadway-overtopping discharge. Left abutment scour ranged from 13.3 to 14.9 ft. The worst-case scour at the left abutment occurred at the 500-year discharge. Right abutment scour ranged from 4.1 to 6.0 ft. The worst-case scour at the right abutment 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/ofr97369","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 10 (CHESTH00030010) on Town Highway 3 (VT 35), crossing the South Branch of Williams River, Chester, Vermont: U.S. Geological Survey Open-File Report 97-369, iv, 52 p., https://doi.org/10.3133/ofr97369.","productDescription":"iv, 52 p.","numberOfPages":"57","costCenters":[],"links":[{"id":170458,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr97369.JPG"},{"id":279756,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0369/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Chester","otherGeospatial":"South Branch Williams River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8469","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":240484,"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":240485,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50140,"text":"ofr97176 - 1997 - Estimates of water use in the western United States in 1990, and water-use trends, 1960-90","interactions":[],"lastModifiedDate":"2012-02-02T00:11:16","indexId":"ofr97176","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":"97-176","title":"Estimates of water use in the western United States in 1990, and water-use trends, 1960-90","language":"ENGLISH","doi":"10.3133/ofr97176","usgsCitation":"Solley, W.B., 1997, Estimates of water use in the western United States in 1990, and water-use trends, 1960-90: U.S. Geological Survey Open-File Report 97-176, 15 p., https://doi.org/10.3133/ofr97176.","productDescription":"15 p.","costCenters":[],"links":[{"id":175284,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a0ce4b07f02db5fc9fa","contributors":{"authors":[{"text":"Solley, Wayne B.","contributorId":61409,"corporation":false,"usgs":true,"family":"Solley","given":"Wayne","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":240831,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ]}