This report provides the results of a detailed Level II analysis of scour potential at structure NEWFTH00350042 on Town Highway 35 crossing Stratton Hill Brook, Newfane, 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 (FHWA, 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 1.16-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forested.
In the study area, Stratton Hill Brook has an incised, striaght channel with a slope of approximately 0.1 ft/ft, an average channel top width of 36 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 121 mm (0.396 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 20, 1996, indicated that the reach was stable.
The Town Highway 34 crossing of Stratton Hill Brook is a 34-ft-long, one-lane bridge consisting of a 32-foot steel-beam span (Vermont Agency of Transportation, written communication, April 6, 1995). The opening length of the structure parallel to the bridge face is 30.8 ft. The bridge is supported by vertical, concrete abutments with upstream wingwalls. The channel is skewed approximately 20 degrees to the opening while the computed opening-skew-to-roadway is 15 degrees.
During the Level I assessment, it was observed that the right abutment footing was exposed 1.5 feet. The only scour protection measure at the site was type-1 stone fill (less than 12 inches diameter) along the downstream left 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 Davis, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for all modelled flows was zero ft. Abutment scour ranged from 2.3 to 3.3 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 Davis, 1995, p. 46). 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/ofr98404","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., and Ivanoff, M.A., 1998, Level II scour analysis for Bridge 42 (NEWFTH00350042) on Town Highway 35, crossing Stratton Hill Brook, Newfane, Vermont: U.S. Geological Survey Open-File Report 98-404, iv, 48 p., https://doi.org/10.3133/ofr98404.","productDescription":"iv, 48 p.","costCenters":[],"links":[{"id":162363,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr98404.JPG"},{"id":279987,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0404/report.pdf"}],"country":"United States","state":"Vermont","city":"Newfane","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a6150","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":241068,"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":241067,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50221,"text":"ofr98152 - 1998 - Level II scour analysis for Bridge 37 (TOWNTH00290037) on Town Highway 29, crossing Mill Brook, Townshend, Vermont","interactions":[],"lastModifiedDate":"2013-12-17T13:42:56","indexId":"ofr98152","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-152","title":"Level II scour analysis for Bridge 37 (TOWNTH00290037) on Town Highway 29, crossing Mill Brook, Townshend, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nTOWNTH00290037 on Town Highway 29 crossing Mill Brook, Townshend, 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 (FHWA, 1993). Results of a Level I scour \ninvestigation also are included in Appendix E of this report. A Level I investigation \nprovides a qualitative geomorphic characterization of the study site. Information on the \nbridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled \nprior to conducting Level I and Level II analyses and is found in appendix D.\nThe site is in the New England Upland section of the New England physiographic province \nin southeastern Vermont. The 13.9-mi2\n drainage area is in a predominantly rural and \nforested basin. In the vicinity of the study site, the surface cover is forest upstream of the \nbridge. Downstream of the bridge the surface cover is pasture on the left bank and shrub and \nbrushland on the right bank.\nIn the study area, Mill Brook has an incised, sinuous channel with a slope of approximately \n0.01 ft/ft, an average channel top width of 53 ft and an average bank height of 8 ft. The \nchannel bed material ranges from gravel to boulder with a median grain size (D50) of 70.0 \nmm (0.230 ft). The geomorphic assessment at the time of the Level I and Level II site visit \non August 14, 1996, indicated that the reach was laterally unstable. There are large cutbanks and point bars upstream and downstream of the bridge. There is also moderate \nfluvial erosion on the upstream left bank and downstream right bank.\nThe Town Highway 29 crossing of Mill Brook is a 33-ft-long, one-lane bridge consisting of \none 30-foot steel-girder span (Vermont Agency of Transportation, written communication, \nApril 7, 1995). The opening length of the structure parallel to the bridge face is 24.8 ft. The \nbridge is supported by vertical, concrete abutments with wingwalls, the downstream left \nwingwall, however, is “laid-up” stone. The channel is skewed approximately 45 degrees to \nthe opening while the computed opening-skew-to-roadway is 25 degrees. 2\nA scour hole 1.0 ft deeper than the mean thalweg depth was observed along the right \nabutment during the Level I assessment. This scour hole continues downstream along the \nright bank and deepens to 1.5 ft deeper than the mean thalweg. The scour protection \nmeasures at the site included type-2 stone fill (less than 36 inches diameter) along the \nupstream left and right banks and along the upstream right wingwall. Type-3 stone fill (less \nthan 48 inches diameter) was along the downstream right wingwall and downstream right \nbank and a short stone wall is on the downstream left bank. 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 Davis, 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 0.0 to 2.1 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Left abutment scour ranged from 6.7 \nto 8.7 ft. The worst-case left abutment scour occurred at the incipient roadway-overtopping \ndischarge. Right abutment scour ranged from 7.8 to 9.5 ft. The worst-case right 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 Davis, 1995, p. 46). 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":"Reston, VA","doi":"10.3133/ofr98152","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and the Federal Highway Administration","usgsCitation":"Burns, R., and Medalie, L., 1998, Level II scour analysis for Bridge 37 (TOWNTH00290037) on Town Highway 29, crossing Mill Brook, Townshend, Vermont: U.S. Geological Survey Open-File Report 98-152, 50 p., https://doi.org/10.3133/ofr98152.","productDescription":"50 p.","additionalOnlineFiles":"N","costCenters":[],"links":[{"id":175942,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr98152.JPG"},{"id":279846,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0152/report.pdf"}],"country":"United States","state":"Vermont","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":"4f4e4b17e4b07f02db6a6303","contributors":{"authors":[{"text":"Burns, R.L.","contributorId":62651,"corporation":false,"usgs":true,"family":"Burns","given":"R.L.","email":"","affiliations":[],"preferred":false,"id":240984,"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":240983,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50222,"text":"ofr9856 - 1998 - Level II scour analysis for Bridge 58 (SPRITH00060058) on Town Highway 6, crossing Baltimore Brook, Springfield, Vermont","interactions":[],"lastModifiedDate":"2013-12-02T09:38:52","indexId":"ofr9856","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-56","title":"Level II scour analysis for Bridge 58 (SPRITH00060058) on Town Highway 6, crossing Baltimore Brook, Springfield, Vermont","language":"ENGLISH","doi":"10.3133/ofr9856","usgsCitation":"Burns, R., and Medalie, L., 1998, Level II scour analysis for Bridge 58 (SPRITH00060058) on Town Highway 6, crossing Baltimore Brook, Springfield, Vermont: U.S. Geological Survey Open-File Report 98-56, 47 p., https://doi.org/10.3133/ofr9856.","productDescription":"47 p.","costCenters":[],"links":[{"id":175943,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":280034,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0056/report.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a5a7b","contributors":{"authors":[{"text":"Burns, R.L.","contributorId":62651,"corporation":false,"usgs":true,"family":"Burns","given":"R.L.","email":"","affiliations":[],"preferred":false,"id":240986,"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":240985,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50200,"text":"ofr98541 - 1998 - Level II scour analysis for Bridge 20 (WALDTH00050020) on Town Highway 5, crossing Stanard Brook, Walden, Vermont","interactions":[],"lastModifiedDate":"2013-12-02T09:46:26","indexId":"ofr98541","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-541","title":"Level II scour analysis for Bridge 20 (WALDTH00050020) on Town Highway 5, crossing Stanard Brook, Walden, Vermont","language":"ENGLISH","doi":"10.3133/ofr98541","usgsCitation":"Burns, R., and Olson, S., 1998, Level II scour analysis for Bridge 20 (WALDTH00050020) on Town Highway 5, crossing Stanard Brook, Walden, Vermont: U.S. Geological Survey Open-File Report 98-541, 54 p., https://doi.org/10.3133/ofr98541.","productDescription":"54 p.","costCenters":[],"links":[{"id":176469,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":280053,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0541/report.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8381","contributors":{"authors":[{"text":"Burns, R.L.","contributorId":62651,"corporation":false,"usgs":true,"family":"Burns","given":"R.L.","email":"","affiliations":[],"preferred":false,"id":240945,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Olson, S.A.","contributorId":58681,"corporation":false,"usgs":true,"family":"Olson","given":"S.A.","email":"","affiliations":[],"preferred":false,"id":240944,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50271,"text":"ofr9815 - 1998 - Level II scour analysis for Bridge 17 (NEWHTH00200017) on Town Highway 20, crossing Little Otter Creek, New Haven, Vermont","interactions":[],"lastModifiedDate":"2016-10-13T15:50:54","indexId":"ofr9815","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-15","title":"Level II scour analysis for Bridge 17 (NEWHTH00200017) on Town Highway 20, crossing Little Otter Creek, New Haven, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure NEWHTH00200017 on Town Highway 20 crossing Little Otter Creek, New Haven, 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 Champlain section of the St. Lawrence Valley physiographic province in west-central Vermont. The 10.8-mi2 drainage area is in a predominantly rural and wetland basin. In the vicinity of the study site, the surface cover is shrubland on the downstream right overbank. The surface cover of the downstream left overbank, the upstream right overbank and the upstream left overbank is wetland and pasture.
In the study area, Little Otter Creek has a meandering channel with a slope of approximately 0.0007 ft/ft, an average channel top width of 97 ft and an average bank height of 5 ft. The channel bed material ranges from silt and clay to cobble. Medium sized silt and clay is the channel material upstream of the approach cross-section and downstream of the exit cross-section. The median grain size (D50) of the silt and clay channel bed material is 1.52 mm (0.005 ft), which was used for contraction and abutment scour computations. From the approach cross-section, under the bridge, and to the exit cross-section, stone fill is the channel bed material. The median grain size (D50) of the stone fill channel bed material is 95.7 mm (0.314 ft). The stone fill median grain size was used solely for armoring computations. The geomorphic assessment at the time of the Level I and Level II site visit on June 11, 1996, indicated that the reach was stable.
The Town Highway 20 crossing of Little Otter Creek is a 32-ft-long, two-lane bridge consisting of a 28-ft steel-beam span (Vermont Agency of Transportation, written communication, December 15, 1995). The opening length of the structure parallel to the bridge face is 24.9 ft. The bridge is supported by almost vertical, concrete abutments. The channel is skewed approximately 15 degrees to the opening while the opening-skew-toroadway is zero degrees.
The scour countermeasures at the site consisted of type-1 stone fill (less than 12 inches diameter) along the left and right abutments, as well as along the upstream left and right banks. Type-2 stone fill (less than 36 inches diameter) was present along the downstream 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 Davis, 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 9.7 to 13.8 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 6.9 to 7.9 ft. Right abutment scour ranged from 10.5 to 11.8 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 Davis, 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/ofr9815","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., and Burns, R.L., 1998, Level II scour analysis for Bridge 17 (NEWHTH00200017) on Town Highway 20, crossing Little Otter Creek, New Haven, Vermont: U.S. Geological Survey Open-File Report 98-15, iv, 51 p., https://doi.org/10.3133/ofr9815.","productDescription":"iv, 51 p.","costCenters":[],"links":[{"id":162288,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":279989,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0015/report.pdf"}],"country":"United States","state":"Vermont","city":"New Haven","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8222","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":241064,"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":241063,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50265,"text":"ofr98156 - 1998 - Level II scour analysis for Bridge 27 (WSTOTH00070027) on Town Highway 7, crossing Jenny Coolidge Brook, Weston, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T13:46:05","indexId":"ofr98156","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-156","title":"Level II scour analysis for Bridge 27 (WSTOTH00070027) on Town Highway 7, crossing Jenny Coolidge Brook, Weston, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure WSTOTH00070027 on Town Highway 7 crossing Jenny Coolidge Brook, Weston, 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 (FHWA, 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 southwestern Vermont. The 2.9-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture downstream of the bridge while upstream of the bridge is forested.
In the study area, the Jenny Coolidge Brook has an incised, sinuous channel with a slope of approximately 0.04 ft/ft, an average channel top width of 51 ft and an average bank height of 6 ft. The channel bed material ranges from sand to boulders with a median grain size (D50) of 122 mm (0.339 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 20, 1996, indicated that the reach was stable.
The Town Highway 7 crossing of the Jenny Coolidge Brook is a 52-ft-long, two-lane bridge consisting of a 50-foot steel-beam span (Vermont Agency of Transportation, written communication, April 7, 1995). The opening length of the structure parallel to the bridge face is 49.2 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 5 degrees to the opening while the computed opening-skew-to-roadway is 15 degrees.
The legs of the skeleton-type right abutment were exposed approximately 2 feet (vertically) and approximately 2 feet (horizontally) during the Level I assessment. Scour protection measures at the site include type-1 stone fill (less than 12 inches diameter) along the downstream right wingwall, and type-2 stone fill (less than 36 inches diameter) along the upstream banks, upstream left wingwall, left abutment, downstream left wingwall and downstream left bank. A stone wall levee extends along the downstream 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 Davis, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for all modelled flows was zero ft. Abutment scour ranged from 3.0 to 4.1 ft. The worst-case left abutment scour occurred at the 100-year discharge. The worst-case 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 particlesize distribution.
It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). 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/ofr98156","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., 1998, Level II scour analysis for Bridge 27 (WSTOTH00070027) on Town Highway 7, crossing Jenny Coolidge Brook, Weston, Vermont: U.S. Geological Survey Open-File Report 98-156, iv, 48 p., https://doi.org/10.3133/ofr98156.","productDescription":"iv, 48 p.","costCenters":[],"links":[{"id":178628,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr98156.JPG"},{"id":279995,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0156/report.pdf"}],"country":"United States","state":"Vermont","city":"Weston","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b19e4b07f02db6a7f95","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":241056,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":50197,"text":"ofr98538 - 1998 - Level II scour analysis for Bridge 10 (GRAFTH00020010) on Town Highway 2 (FAS 126 and State Route 121), crossing the Saxtons River, Grafton, Vermont","interactions":[],"lastModifiedDate":"2013-12-02T09:47:30","indexId":"ofr98538","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-538","title":"Level II scour analysis for Bridge 10 (GRAFTH00020010) on Town Highway 2 (FAS 126 and State Route 121), crossing the Saxtons River, Grafton, Vermont","language":"ENGLISH","doi":"10.3133/ofr98538","usgsCitation":"Boehmler, E., and Hammond, R., 1998, Level II scour analysis for Bridge 10 (GRAFTH00020010) on Town Highway 2 (FAS 126 and State Route 121), crossing the Saxtons River, Grafton, Vermont: U.S. Geological Survey Open-File Report 98-538, 51 p., https://doi.org/10.3133/ofr98538.","productDescription":"51 p.","costCenters":[],"links":[{"id":176466,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":280056,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0538/report.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8475","contributors":{"authors":[{"text":"Boehmler, E.M.","contributorId":88405,"corporation":false,"usgs":true,"family":"Boehmler","given":"E.M.","affiliations":[],"preferred":false,"id":240939,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hammond, R.E.","contributorId":56292,"corporation":false,"usgs":true,"family":"Hammond","given":"R.E.","email":"","affiliations":[],"preferred":false,"id":240938,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50209,"text":"ofr98557 - 1998 - Level II scour analysis for Bridge 33 (PFRDTH00230033) on Town Highway 23, crossing Otter Creek, Pittsford, Vermont","interactions":[],"lastModifiedDate":"2013-12-02T09:43:34","indexId":"ofr98557","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-557","title":"Level II scour analysis for Bridge 33 (PFRDTH00230033) on Town Highway 23, crossing Otter Creek, Pittsford, Vermont","language":"ENGLISH","doi":"10.3133/ofr98557","usgsCitation":"Boehmler, E., and Ivanoff, M., 1998, Level II scour analysis for Bridge 33 (PFRDTH00230033) on Town Highway 23, crossing Otter Creek, Pittsford, Vermont: U.S. Geological Survey Open-File Report 98-557, 52 p., https://doi.org/10.3133/ofr98557.","productDescription":"52 p.","costCenters":[],"links":[{"id":176577,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":280046,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0557/report.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b19e4b07f02db6a7746","contributors":{"authors":[{"text":"Boehmler, E.M.","contributorId":88405,"corporation":false,"usgs":true,"family":"Boehmler","given":"E.M.","affiliations":[],"preferred":false,"id":240963,"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":240962,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50193,"text":"ofr98528 - 1998 - Level II scour analysis for Bridge 4 (SUTTTH00450004) on Town Highway 45, crossing Calendar Brook, Sutton, Vermont","interactions":[],"lastModifiedDate":"2019-06-04T12:34:20","indexId":"ofr98528","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-528","title":"Level II scour analysis for Bridge 4 (SUTTTH00450004) on Town Highway 45, crossing Calendar Brook, Sutton, Vermont","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/ofr98528","usgsCitation":"Serra, M., and Medalie, L., 1998, Level II scour analysis for Bridge 4 (SUTTTH00450004) on Town Highway 45, crossing Calendar Brook, Sutton, Vermont: U.S. Geological Survey Open-File Report 98-528, 48 p., https://doi.org/10.3133/ofr98528.","productDescription":"48 p.","costCenters":[],"links":[{"id":176373,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":280060,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0528/report.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a61bf","contributors":{"authors":[{"text":"Serra, M.M.","contributorId":81974,"corporation":false,"usgs":true,"family":"Serra","given":"M.M.","email":"","affiliations":[],"preferred":false,"id":240933,"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":240932,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50226,"text":"ofr9887 - 1998 - Level II scour analysis for Bridge 35, (ANDOVT00110035) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T12:58:36","indexId":"ofr9887","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-87","title":"Level II scour analysis for Bridge 35, (ANDOVT00110035) 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 ANDOVT00110035 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 (Federal Highway Administration, 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 south-central Vermont. The 4.65-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest on the left bank and small trees and brush on the right bank upstream and downstream of the bridge.
In the study area, the Middle Branch Williams River has an incised, meandering channel with a slope of approximately 0.02 ft/ft, an average channel top width of 57 ft and an average bank height of 4 ft. The channel bed material ranges from gravel to boulder with a median grain size (D50) of 31.4 mm (0.103 ft). The geomorphic assessment at the time of the Level I and Level II site visit on August 28, 1996, indicated that the reach was laterally unstable. There are cut-banks upstream and downstream of the bridge and an island in the channel upstream.
The State Route 11 crossing of the Middle Branch Williams River is a 28-ft-long, two-lane bridge consisting of one 24-ft concrete tee-beam span (Vermont Agency of Transportation, written communication, March 28, 1995). The opening length of the structure parallel to the bridge face is 23.6 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 45 degrees to the opening while the computed opening-skew-to-roadway is 25 degrees.
A scour hole ranging from 1.5 to 1.75 ft deeper than the mean thalweg depth was observed along the upstream left wingwall, the left abutment, and the downstream left wingwall during the Level I assessment. The scour countermeasures at the site included type-1 stone fill (less than 12 inches diameter) at the right road approach upstream and downstream of the bridge and type-2 stone fill (less than 36 inches diameter) at the left road approach upstream and downstream of the bridge. 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 Davis, 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 2.0 to 4.3 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 14.4 to 16.5 ft at the left abutment and from 6.3 to 8.8 ft at the right abutment. 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 Davis, 1995, p. 46). 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/ofr9887","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Burns, R.L., and Wild, E.C., 1998, Level II scour analysis for Bridge 35, (ANDOVT00110035) on State Route 11, crossing the Middle Branch Williams River, Andover, Vermont: U.S. Geological Survey Open-File Report 98-87, iv, 51 p., https://doi.org/10.3133/ofr9887.","productDescription":"iv, 51 p.","costCenters":[],"links":[{"id":175947,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr9887.JPG"},{"id":280031,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0087/report.pdf"}],"country":"United States","state":"Vermont","city":"Andover","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a6464","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240993,"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":240994,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50192,"text":"ofr98527 - 1998 - Level II scour analysis for Bridge 20 (MENDTH00070020) on Town Highway 7, crossing Mendon Brook, Mendon, Vermont","interactions":[],"lastModifiedDate":"2013-12-02T09:51:01","indexId":"ofr98527","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-527","title":"Level II scour analysis for Bridge 20 (MENDTH00070020) on Town Highway 7, crossing Mendon Brook, Mendon, Vermont","language":"ENGLISH","doi":"10.3133/ofr98527","usgsCitation":"Willoughby, S., and Severance, T., 1998, Level II scour analysis for Bridge 20 (MENDTH00070020) on Town Highway 7, crossing Mendon Brook, Mendon, Vermont: U.S. Geological Survey Open-File Report 98-527, 50 p., https://doi.org/10.3133/ofr98527.","productDescription":"50 p.","costCenters":[],"links":[{"id":176372,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":280061,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0527/report.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8146","contributors":{"authors":[{"text":"Willoughby, S.A.","contributorId":87187,"corporation":false,"usgs":true,"family":"Willoughby","given":"S.A.","email":"","affiliations":[],"preferred":false,"id":240930,"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":240931,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50268,"text":"ofr9823 - 1998 - Level II scour analysis for Bridge 46 (LINCTH00060046) on Town Highway 6, crossing the New Haven River, Lincoln, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T13:59:57","indexId":"ofr9823","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-23","title":"Level II scour analysis for Bridge 46 (LINCTH00060046) on Town Highway 6, crossing the New Haven River, Lincoln, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure LINCTH00060046 on Town Highway 6 crossing the New Haven River, Lincoln, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D.
The site is in the Green Mountain section of the New England physiographic province in west-central Vermont. The 45.9-mi2 drainage area is in a predominantly suburban and forested basin. In the vicinity of the study site, the surface cover is forest upstream of the bridge. The downstream right overbank near the bridge is suburban with buildings, homes, lawns, and pavement (less than fifty percent). The downstream left overbank is brushland while the immediate banks have dense woody vegetation.
In the study area, the New Haven River has an incised, sinuous channel with a slope of approximately 0.01 ft/ft, an average channel top width of 95 ft and an average bank height of 7 ft. The channel bed material ranges from sand to bedrock with a median grain size (D50) of 120.7 mm (0.396 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 13, 1996, indicated that the reach was stable.
The Town Highway 34 crossing of the New Haven River is a 85-ft-long, two-lane bridge consisting of an 80-foot steel arch truss (Vermont Agency of Transportation, written communication, December 14, 1995). The opening length of the structure parallel to the bridge face is 69 feet. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 25 degrees to the opening while the opening-skew-to-roadway is 5 degrees.
A scour hole 2.0 ft deeper than the mean thalweg depth was observed in the downstream channel during the Level I assessment. Protection measures at the site include type-1 stone fill (less than 12 inches diameter) at the upstream left wingwall, type-2 stone fill (less than 36 inches diameter) at the downstream end of the downstream left wingwall, and type-3 stone fill (less than 48 inches diameter) at the upstream right wingwall and the downstream end of the downstream right wingwall. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E.
Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995). Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for all modelled flows ranged from 0.0 to 1.7 ft. The worst-case contraction scour occurred at the incipient roadway-overtopping discharge. Left abutment scour ranged from 12.9 to 17.8 ft. Right abutment scour ranged from 5.9 to 11.9 ft. The worst-case 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 Davis, 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/ofr9823","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., 1998, Level II scour analysis for Bridge 46 (LINCTH00060046) on Town Highway 6, crossing the New Haven River, Lincoln, Vermont: U.S. Geological Survey Open-File Report 98-23, iv, 51 p., https://doi.org/10.3133/ofr9823.","productDescription":"iv, 51 p.","costCenters":[],"links":[{"id":178631,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr9823.JPG"},{"id":279992,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0023/report.pdf"}],"country":"United States","state":"Vermont","city":"Lincoln","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a6077","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":241059,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":50208,"text":"ofr98556 - 1998 - Level II scour analysis for Bridge 37 (PLYMTH00080037) on Town Highway 8, crossing Broad Brook, Plymouth, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T15:43:04","indexId":"ofr98556","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-556","title":"Level II scour analysis for Bridge 37 (PLYMTH00080037) on Town Highway 8, crossing Broad Brook, Plymouth, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure PLYMTH00080037 on Town Highway 8 crossing Broad Brook, Plymouth, 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 (FHWA, 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 in south-central Vermont. The 5.6-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest upstream and downstream of the bridge.
In the study area, Broad Brook has an incised, sinuous channel with a slope of approximately 0.02 ft/ft, an average channel top width of 46 ft and an average bank height of 5 ft. The channel bed material ranges from gravel to boulders with a median grain size (D50) of 87.5 mm (0.287 ft). The geomorphic assessment at the time of the Level I and Level II site visit on October 3, 1995, indicated that the reach was laterally unstable due to cut-banks present on the upstream left bank and the downstream left and right banks.
The Town Highway 8 crossing of Broad Brook is a 31-ft-long, one-lane bridge consisting of a 28-foot steel-stringer span (Vermont Agency of Transportation, written communication, March 22, 1995). The opening length of the structure parallel to the bridge face is 27.0 ft. The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 15 degrees to the opening while the opening-skew-to-roadway is 15 degrees.
During the Level I assessment, it was observed that the left abutment footing was exposed 1.25 ft at the downstream end, and the subfooting was exposed 1 ft. Scour protection measures at the site included type-1 stone fill (less than 12 inches diameter) along the upstream right wingwall, the right abutment and the downstream right wingwall. Type-2 stone fill (less than 36 inches diameter) was along the upstream left wingwall, the upstream end of the left abutment and the downstream end of the downstream left wingwall. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E.
Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 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 0.5 ft. The worst-case contraction scour occurred at the incipient roadway-overtopping discharge, which was less than the 100-year discharge. Left abutment scour ranged from 11.1 to 12.0 ft. Right abutment scour ranged from 3.0 to 7.7 ft. The worst-case abutment scour occurred at the 500-year discharge. Pier scour ranged from 6.2 to 7.1 ft. The worst-case pier scour also 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 Davis, 1995, p. 46). 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/ofr98556","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., and Medalie, L., 1998, Level II scour analysis for Bridge 37 (PLYMTH00080037) on Town Highway 8, crossing Broad Brook, Plymouth, Vermont: U.S. Geological Survey Open-File Report 98-556, iv, 50 p., https://doi.org/10.3133/ofr98556.","productDescription":"iv, 50 p.","costCenters":[],"links":[{"id":176576,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr98556.JPG"},{"id":280047,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0556/report.pdf"}],"country":"United States","state":"Vermont","city":"Plymouth","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a62f7","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":240961,"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":240960,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50206,"text":"ofr98554 - 1998 - Level II scour analysis for Bridge 32 (BURKTH00440032) on Town Highway 44, crossing Roundy Brook, Burke, Vermont","interactions":[],"lastModifiedDate":"2013-12-02T09:44:32","indexId":"ofr98554","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-554","title":"Level II scour analysis for Bridge 32 (BURKTH00440032) on Town Highway 44, crossing Roundy Brook, Burke, Vermont","language":"ENGLISH","doi":"10.3133/ofr98554","usgsCitation":"Serra, M., and Boehmler, E., 1998, Level II scour analysis for Bridge 32 (BURKTH00440032) on Town Highway 44, crossing Roundy Brook, Burke, Vermont: U.S. Geological Survey Open-File Report 98-554, 49 p., https://doi.org/10.3133/ofr98554.","productDescription":"49 p.","costCenters":[],"links":[{"id":176574,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":280049,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0554/report.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b19e4b07f02db6a7d5c","contributors":{"authors":[{"text":"Serra, M.M.","contributorId":81974,"corporation":false,"usgs":true,"family":"Serra","given":"M.M.","email":"","affiliations":[],"preferred":false,"id":240956,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Boehmler, E.M.","contributorId":88405,"corporation":false,"usgs":true,"family":"Boehmler","given":"E.M.","affiliations":[],"preferred":false,"id":240957,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50257,"text":"ofr98289 - 1998 - Level II scour analysis for Bridge 42 (BRNETH00810042) on Town Highway 81, crossing Stevens River, Barnet, Vermont","interactions":[],"lastModifiedDate":"2013-12-02T09:23:25","indexId":"ofr98289","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-289","title":"Level II scour analysis for Bridge 42 (BRNETH00810042) on Town Highway 81, crossing Stevens River, Barnet, Vermont","language":"ENGLISH","doi":"10.3133/ofr98289","usgsCitation":"Serra, M., 1998, Level II scour analysis for Bridge 42 (BRNETH00810042) on Town Highway 81, crossing Stevens River, Barnet, Vermont: U.S. Geological Survey Open-File Report 98-289, 51 p., https://doi.org/10.3133/ofr98289.","productDescription":"51 p.","costCenters":[],"links":[{"id":179415,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":280003,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0289/report.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a6166","contributors":{"authors":[{"text":"Serra, M.M.","contributorId":81974,"corporation":false,"usgs":true,"family":"Serra","given":"M.M.","email":"","affiliations":[],"preferred":false,"id":241042,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":50247,"text":"ofr9855 - 1998 - Level II scour analysis for Bridge 4 (PROCTH00060004) on Town Highway 6, crossing Otter Creek, Proctor, Vermont","interactions":[],"lastModifiedDate":"2013-12-02T09:27:17","indexId":"ofr9855","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-55","title":"Level II scour analysis for Bridge 4 (PROCTH00060004) on Town Highway 6, crossing Otter Creek, Proctor, Vermont","language":"ENGLISH","doi":"10.3133/ofr9855","usgsCitation":"Ivanoff, M., and Medalie, L., 1998, Level II scour analysis for Bridge 4 (PROCTH00060004) on Town Highway 6, crossing Otter Creek, Proctor, Vermont: U.S. Geological Survey Open-File Report 98-55, 49 p., https://doi.org/10.3133/ofr9855.","productDescription":"49 p.","costCenters":[],"links":[{"id":178621,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":280012,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0055/report.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a6205","contributors":{"authors":[{"text":"Ivanoff, M.A.","contributorId":45758,"corporation":false,"usgs":true,"family":"Ivanoff","given":"M.A.","email":"","affiliations":[],"preferred":false,"id":241026,"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":241025,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50202,"text":"ofr98543 - 1998 - Level II scour analysis for Bridge 40 (ROCKTH00140040) on Town Highway 14, crossing the Williams River, Rockingham, Vermont","interactions":[],"lastModifiedDate":"2016-08-25T13:01:59","indexId":"ofr98543","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-543","title":"Level II scour analysis for Bridge 40 (ROCKTH00140040) on Town Highway 14, crossing the Williams River, Rockingham, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure ROCKTH00140040 on Town Highway 14 crossing the Williams River, Rockingham, 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 (FHWA, 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 99.2-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture downstream of the bridge. Upstream of the bridge, the left bank is forested and the right bank is suburban.
In the study area, the Williams River has an incised, sinuous channel with a slope of approximately 0.005 ft/ft, an average channel top width of 154 ft and an average bank height of 11 ft. The channel bed material ranges from silt and clay to cobble with a median grain size (D50) of 45.4 mm (0.149 ft). The geomorphic assessment at the time of the Level I and Level II site visit on September 4, 1996, indicated that the reach was stable.
The Town Highway 14 crossing of the Williams River is a 106-ft-long, one-lane covered bridge consisting of two steel-beam spans with a maximum span length of 73 ft (Vermont Agency of Transportation, written communication, April 6, 1995). The opening length of the structure parallel to the bridge face is 94.5 ft. The bridge is supported by a vertical, concrete abutment with wingwalls on the left, a vertical, laid-up stone abutment on the right and a concrete pier. The channel is skewed approximately 10 degrees to the opening while the opening-skew-to-roadway is zero degrees.
A scour hole 2.1 ft deeper than the mean thalweg depth was observed towards the left side of the channel under and just downstream of the bridge during the Level I assessment. Scour protection measures at the site included type-1 stone fill (less than 12 inches diameter) at the upstream end of the upstream left wingwall and type-2 stone fill (less than 36 inches diameter) along the upstream left bank 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 Davis, 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 13.9 to 19.2 ft. Right abutment scour ranged from 7.0 to 11.7 ft. The worst-case abutment scour occurred at the 500-year discharge. Pier scour ranged from 18.7 to 24.7 ft and the worst case 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 particlesize distribution.
It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). 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/ofr98543","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Burns, R.L., and Wild, E.C., 1998, Level II scour analysis for Bridge 40 (ROCKTH00140040) on Town Highway 14, crossing the Williams River, Rockingham, Vermont: U.S. Geological Survey Open-File Report 98-543, iv, 55 p., https://doi.org/10.3133/ofr98543.","productDescription":"iv, 55 p.","costCenters":[],"links":[{"id":176471,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/of/1998/0543/report-thumb.jpg"},{"id":86308,"rank":300,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0543/report.pdf","linkFileType":{"id":1,"text":"pdf"}}],"country":"United States","state":"Vermont","city":"Rockingham","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a61a6","contributors":{"authors":[{"text":"Burns, Ronda L.","contributorId":71602,"corporation":false,"usgs":true,"family":"Burns","given":"Ronda","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240948,"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":240949,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":50297,"text":"ofr9818 - 1998 - Bibliography of National Drilling Company--United States Geological Survey reports on the water resources of Abu Dhabi Emirate, 1987-1997","interactions":[],"lastModifiedDate":"2012-02-02T00:10:25","indexId":"ofr9818","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-18","title":"Bibliography of National Drilling Company--United States Geological Survey reports on the water resources of Abu Dhabi Emirate, 1987-1997","language":"ENGLISH","doi":"10.3133/ofr9818","usgsCitation":"Hutchinson, C.B., 1998, Bibliography of National Drilling Company--United States Geological Survey reports on the water resources of Abu Dhabi Emirate, 1987-1997: U.S. Geological Survey Open-File Report 98-18, iv, 63 p. : ill., map ; 29 cm., https://doi.org/10.3133/ofr9818.","productDescription":"iv, 63 p. : ill., map ; 29 cm.","costCenters":[],"links":[{"id":169502,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/of/1998/0018/report-thumb.jpg"},{"id":86310,"rank":300,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0018/report.pdf","linkFileType":{"id":1,"text":"pdf"}}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a51e4b07f02db629969","contributors":{"authors":[{"text":"Hutchinson, C. B.","contributorId":94655,"corporation":false,"usgs":true,"family":"Hutchinson","given":"C.","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":241142,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":50207,"text":"ofr98555 - 1998 - Level II scour analysis for Bridge 20 (BURKTH00560020) on Town Highway 56, crossing the East Branch Passumpsic River, Burke, Vermont","interactions":[],"lastModifiedDate":"2013-12-02T09:44:14","indexId":"ofr98555","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"98-555","title":"Level II scour analysis for Bridge 20 (BURKTH00560020) on Town Highway 56, crossing the East Branch Passumpsic River, Burke, Vermont","language":"ENGLISH","doi":"10.3133/ofr98555","usgsCitation":"Serra, M., and Severance, T., 1998, Level II scour analysis for Bridge 20 (BURKTH00560020) on Town Highway 56, crossing the East Branch Passumpsic River, Burke, Vermont: U.S. Geological Survey Open-File Report 98-555, 50 p., https://doi.org/10.3133/ofr98555.","productDescription":"50 p.","costCenters":[],"links":[{"id":176575,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":280048,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0555/report.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8347","contributors":{"authors":[{"text":"Serra, M.M.","contributorId":81974,"corporation":false,"usgs":true,"family":"Serra","given":"M.M.","email":"","affiliations":[],"preferred":false,"id":240958,"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":240959,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":44311,"text":"ofr97102 - 1998 - Hydrogeology and water quality of the Clinton Street-Ballpark Aquifer near Johnson City, New York","interactions":[],"lastModifiedDate":"2017-04-06T11:08:21","indexId":"ofr97102","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1998","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":"97-102","title":"Hydrogeology and water quality of the Clinton Street-Ballpark Aquifer near Johnson City, New York","docAbstract":"The Clinton Street-Ballpark aquifer, in the Susquehanna River valley in southern Broome County, N.Y., supplies drinking water to the Village of Johnson City near Binghamton. The hydrogeology and water quality of the aquifer were studied in 1994-95 to identify the source area of 1,1,1-trichloroethane, which was detected at the Johnson City Camden Street wellfield in 1991.
The aquifer is generally 100 to 150 ft thick and consists primarily of ice-contact deposits of silty sand and gravel that are overlain by outwash deposits of sand and gravel. These two types of deposits are separated by lacustrine silt and clay of variable thickness into an upper and a lower layer of the aquifer. The coarse deposits form a single aquifer in areas where the lacustrine deposits are absent.
Synoptic water-level surveys indicated that ground water moves from upgradient areas flanking the aquifer boundaries toward two major pumping centers?the Anitec wellfield in Binghamton and the Camden Street wellfield in Johnson City. Areas contributing recharge to municipal and industrial wells in the aquifer were delineated by a previously developed groundwater- flow model. The residence time of ground water within the area contributing recharge to Johnson City well no. 2 in the Camden Street wellfield was estimated to be less than 6 years.
1,1,1-Trichloroethane, trichloroethene, and their metabolites were detected in ground water at several locations in and near Johnson City. Relatively high concentrations of 1,1,1-trichloroethane were found in ground water about 3,000 ft north of the Camden Street wellfield. The suspected source is an area bordered on the south by Field Street, on the north by Harry L. Drive, on the east by New York State Route 201, and on the west by Marie Street. A trichloroethene metabolite, cis-1,2-dichloroethene, appears to be migrating westward from U.S. Air Force Plant 59 toward the Camden Street well-field, 1,000 ft southwest of the plant, although this compound has not been detected in water pumped by municipal wells, possibly because it has become diluted by ground water from other locations within the contributing area to the wells.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/ofr97102","collaboration":"Prepared in cooperation with the U.S. Air Force","usgsCitation":"Coon, W.F., Yager, R.M., Surface, J.M., Randall, A.D., and Eckhardt, D.A., 1998, Hydrogeology and water quality of the Clinton Street-Ballpark Aquifer near Johnson City, New York: U.S. Geological Survey Open-File Report 97-102, Report: 63 p.; 5 Plates, https://doi.org/10.3133/ofr97102.","productDescription":"Report: 63 p.; 5 Plates","onlineOnly":"Y","additionalOnlineFiles":"Y","costCenters":[{"id":474,"text":"New York Water Science Center","active":true,"usgs":true}],"links":[{"id":326220,"rank":5,"type":{"id":17,"text":"Plate"},"url":"https://pubs.usgs.gov/of/1997/0102/ofr1997102_plate3.pdf","text":"Plate 3 ","size":"7.52 MB","linkFileType":{"id":1,"text":"pdf"},"description":"OFR 1996-0102","linkHelpText":"- Areas contributing ground water to municipal and industrial wells, and travel times of selected flow lines near Johnson, City, N.Y., 1994"},{"id":326221,"rank":6,"type":{"id":17,"text":"Plate"},"url":"https://pubs.usgs.gov/of/1997/0102/ofr1997102_plate4.pdf","text":"Plate 4 ","size":"5.67 MB","linkFileType":{"id":1,"text":"pdf"},"description":"OFR 1996-0102","linkHelpText":"- Concentration of 1,1,1- Trichloroethane (1,1,1-TCA) and 1,1-Dichlorethane (1,1-DCA) in ground water, Johnson City, N.Y., 1994–95"},{"id":326218,"rank":3,"type":{"id":17,"text":"Plate"},"url":"https://pubs.usgs.gov/of/1997/0102/ofr1997102_plate1.pdf","text":"Plate 1","size":"7.84 MB","linkFileType":{"id":1,"text":"pdf"},"description":"OFR 1996-0102","linkHelpText":" - Location of wells and surface-water measurement sites in Binghamton and Johnson City, N.Y."},{"id":169353,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/of/1997/0102/coverthb.jpg"},{"id":3724,"rank":2,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1997/0102/ofr19970102.pdf","text":"Report","size":"644 KB","linkFileType":{"id":1,"text":"pdf"},"description":"OFR 1996-0102"},{"id":326219,"rank":4,"type":{"id":17,"text":"Plate"},"url":"https://pubs.usgs.gov/of/1997/0102/ofr1997102_plate2.pdf","text":"Plate 2 ","size":"637 MB","linkFileType":{"id":1,"text":"pdf"},"description":"OFR 1996-0102","linkHelpText":"- Water-table and selected ground-water flow directions in the unconfined layer of the Clinton Street-Ballpark aquifer, Broome County, N.Y., May 1995"},{"id":326222,"rank":7,"type":{"id":17,"text":"Plate"},"url":"https://pubs.usgs.gov/of/1997/0102/ofr1997102_plate5.pdf","text":"Plate 5 ","size":"4.37 MB","linkFileType":{"id":1,"text":"pdf"},"description":"OFR 1996-0102","linkHelpText":"- Concentrations of 1,1,1-Trichlorethene (TCE) and cis-1,2-Dichloroethene (cis-1,2-DCE) in ground water, Johnson City, N.Y., 1994–95"}],"contact":"Director, New York Water Science Center
U.S. Geological Survey
425 Jordan Rd
Troy, NY 12180
(518) 285-5695
http://ny.water.usgs.gov/
This report provides the results of a detailed Level II analysis of scour potential at structure LINCTH00010013 on Town Highway 1 crossing Cota Brook, Lincoln, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (FHWA, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D.
The site is in the Green Mountain section of the New England physiographic province in west-central Vermont. The 3.0-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is forest along the upstream right bank and brushland along the upstream left bank. Downstream of the bridge, the surface cover is pasture along the left and right banks.
In the study area, Cota Brook has an sinuous channel with a slope of approximately 0.01 ft/ ft, an average channel top width of 30 ft and an average bank height of 2 ft. The channel bed material ranges from sand to cobble with a median grain size (D50) of 34.7 mm (0.114 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 10, 1996, indicated that the reach was laterally unstable due to cut-banks and wide, vegetated point bars upstream and downstream of the bridge.
The Town Highway 1 crossing of Cota Brook is a 38-ft-long, two-lane bridge consisting of a 36-foot steel-stringer span (Vermont Agency of Transportation, written communication, December 14, 1995). The opening length of the structure parallel to the bridge face is 34.4 ft. The bridge is supported by vertical, concrete abutments. The channel is skewed approximately 15 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 along the upstream right bank during the Level I assessment. Along the right abutment, it is 0.25 ft deeper than the mean thalweg depth. Scour protection measures at the site included type-1 stone fill (less than 12 inches diameter) along the upstream right bank and type-2 stone fill (less than 36 inches diameter) along the left and right abutments and along the downstream left 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 Davis, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows.
Contraction scour for all modelled flows ranged from 0.0 to 1.7 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 9.1 to 11.3 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 Davis, 1995, p. 46). 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/ofr98157","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Wild, E.C., 1998, Level II scour analysis for Bridge 13 (LINCTH00010013) on Town Highway 1, crossing Cota Brook, Lincoln, Vermont: U.S. Geological Survey Open-File Report 98-157, iv, 49 p., https://doi.org/10.3133/ofr98157.","productDescription":"iv, 49 p.","costCenters":[],"links":[{"id":178627,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr98157.JPG"},{"id":279996,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1998/0157/report.pdf"}],"country":"United States","state":"Vermont","city":"Lincoln","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8483","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":241055,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ]}