{"pageNumber":"417","pageRowStart":"10400","pageSize":"25","recordCount":36991,"records":[{"id":21850,"text":"ofr96460 - 1996 - \"The Great Cataract\" - Effects of Late Holocene Debris Flows on Lava Falls Rapid, Grand Canyon National National Park, Arizona","interactions":[],"lastModifiedDate":"2012-02-02T00:07:42","indexId":"ofr96460","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-460","title":"\"The Great Cataract\" - Effects of Late Holocene Debris Flows on Lava Falls Rapid, Grand Canyon National National Park, Arizona","docAbstract":"Lava Falls Rapid is the most formidable reach of whitewater on the Colorado River in Grand Canyon and is one of the most famous rapids in the world. Although the rapid was once thought to be controlled by the remnants of lava dams of Pleistocene age, Lava Falls was created and is maintained by frequent debris flows from Prospect Canyon. We used 232 historical photographs, of which 121 were replicated, and 14C and 3He dating methods to reconstruct the ages and, in some cases, the magnitudes of late Holocene debris flows. We quantified the interaction between Prospect Canyon debris flows and the Colorado River using image processing of the historical photographs.\r\n\r\nThe highest and oldest debris-flow deposits on the debris fan yielded a 3He date of 2.9?0.6 ka (950 BC), which indicates predominately late Holocene aggradation of one of the largest debris fans in Grand Canyon. The deposit, which has a 25-m escarpment caused by river reworking, crossed the Colorado River and raised its base level by 30 m for an indeterminate, although probably short, period. We mapped depositional surfaces of 6 debris flows that occurred after 950 BC. The most recent prehistoric debris flow occurred no more than 500 years ago (AD 1434).\r\n\r\nFrom April 1872 to July 1939, no debris flows occurred in Prospect Canyon. Debris flows in 1939, 1954, 1955, 1963, 1966, and 1995 constricted the Colorado River between 35 and 80 percent and completely changed the pattern of flow through the rapid. The debris flows had discharges estimated between about 290 and 1,000 m3/s and transported boulders as heavy as 30 Mg. The recurrence interval of these debris flows, calculated from the volume of the aggraded debris fan, ranged from 35 to 200 yrs. The 1939 debris flow in Prospect Canyon appears to have been the largest debris flow in Grand Canyon during the last 125 years.\r\n\r\nDebris flows in Prospect Canyon are initiated by streamflow pouring over a 325-m waterfall onto unconsolidated colluvium, a process called the firehose effect. Floods in Prospect Valley above the waterfall are generated during regional winter storms, localized summer thunderstorms, and occasional tropical cyclones. Winter precipitation has increased in the Grand Canyon region since the early 1960s, and the most recent debris flows have occurred during winter storms. Summer rainfall has declined in the same period, decreasing the potential for debris flows in the summer months.\r\n\r\nThe history of river reworking of the Prospect Canyon debris fan illustrates the interrelation between tributary debris fans and mainstem floods in bedrock canyons. Lava Falls Rapid did not change despite Colorado River floods of 8,500 m3/s in 1884 and 6,230 m3/s in 1921. Floods up to 3,540 m3/s that occurred after the historical, pre-dam debris flows removed most of the deposits within 3 years. Releases in 1965 from Glen Canyon Dam that were above powerplant capacity but less than 1,640 m3/s removed most of the debris fan deposited in 1963, and the combination of dam releases and a 1973 flood on the Little Colorado River removed the 1966 aggradation. About 4,800 m3 of the 1995 deposit was reworked on the day of the 1995 debris flow, dam releases of less than 570 m3/s had not reworked the remainder of the aggraded debris fan.\r\n\r\nLava Falls Rapid has been the most unstable reach of whitewater in Grand Canyon during the late Holocene and particularly during the last 120 years. Rapids in bedrock canyons controlled by tributary deposition in the main channel are aggradational features that reflect the net effect of tributary-mainstem interactions. Boulders that form the core of rapids in Grand Canyon are essentially immobile by both regulated and unregulated Colorado River flows. Historical operation of Glen Canyon Dam, which was completed in 1963, has reduced the potential for reworking of debris fans, and has accelerated the rate of net aggradation at the mouths of tributary canyons. Because debris fans that formed after 196","language":"ENGLISH","publisher":"U.S. Geological Survey,","doi":"10.3133/ofr96460","issn":"0566-8174","usgsCitation":"Webb, R., Melis, T., Wise, T.W., and Elliott, J.G., 1996, \"The Great Cataract\" - Effects of Late Holocene Debris Flows on Lava Falls Rapid, Grand Canyon National National Park, Arizona: U.S. Geological Survey Open-File Report 96-460, 96 p. :ill. (1 col.), maps ;28 cm., https://doi.org/10.3133/ofr96460.","productDescription":"96 p. :ill. (1 col.), maps ;28 cm.","numberOfPages":"96","costCenters":[{"id":568,"text":"Southwest Biological Science Center","active":true,"usgs":true}],"links":[{"id":153203,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":1243,"rank":100,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.water.usgs.gov/ofr96460","linkFileType":{"id":5,"text":"html"}}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"53cd4901e4b0b290850eecd3","contributors":{"authors":[{"text":"Webb, Robert H. rhwebb@usgs.gov","contributorId":1573,"corporation":false,"usgs":false,"family":"Webb","given":"Robert H.","email":"rhwebb@usgs.gov","affiliations":[{"id":12625,"text":"School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA","active":true,"usgs":false}],"preferred":false,"id":185965,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Melis, Theodore S. 0000-0003-0473-3968 tmelis@usgs.gov","orcid":"https://orcid.org/0000-0003-0473-3968","contributorId":1829,"corporation":false,"usgs":true,"family":"Melis","given":"Theodore S.","email":"tmelis@usgs.gov","affiliations":[{"id":568,"text":"Southwest Biological Science Center","active":true,"usgs":true}],"preferred":true,"id":185966,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Wise, Thomas W.","contributorId":89162,"corporation":false,"usgs":true,"family":"Wise","given":"Thomas","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":185967,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Elliott, John G. jelliott@usgs.gov","contributorId":832,"corporation":false,"usgs":true,"family":"Elliott","given":"John","email":"jelliott@usgs.gov","middleInitial":"G.","affiliations":[],"preferred":true,"id":185964,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}}
,{"id":23810,"text":"ofr96117 - 1996 - Geohydrology and potential water-supply development on Bumkin, Gallops, Georges, Grape, Lovell, and Peddocks Islands, eastern Massachusetts","interactions":[],"lastModifiedDate":"2020-03-27T10:41:23","indexId":"ofr96117","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-117","title":"Geohydrology and potential water-supply development on Bumkin, Gallops, Georges, Grape, Lovell, and Peddocks Islands, eastern Massachusetts","docAbstract":"<p>An investigation of the geohydrology and of the potential for water-supply development on several of the Boston Harbor Islands, eastern Massachusetts, was conducted to evaluate the possibility of developing a permanent small-capacity water supply to support recreational activities, such as camping, hiking, and swimming. The Boston Harbor Islands, including Bumkin, Gallops, Georges, Grape, Lovell, and Peddocks Islands are part of a larger group of glacially deposited drumlins, which are composed of thick, dense, homogeneous till in their core that are overlain by a thin layer of stratified-beach deposits. The surficial materials over-lie a weathered zone of the metasedimentary Cambridge Argillite in the Boston Harbor area and were deposited by continental ice sheets that covered New England twice during the late Pleistocene Epoch, and by near-shore processes in the Holocene Epoch. The thickness of these materials range from less than 1 to about 300 feet where present. </p><p>The till was deposited by glacial ice and is characterized as an unsorted matrix of sand, silt, and clay with variable amounts of stones and large boulders. The stratified deposits primarily consist of sorted and layered sand and gravel that accumulated and formed the beaches and tombolos of the harbor islands. These deposits overlie the till at altitudes generally less than 10 feet above sea level.</p><p> A cross-sectional, ground-water-flow model was developed to estimate depth to the water table for a hypothetical drumlin-island flow system, which was assumed to be representative of the drumlin islands in Boston Harbor. Areas were identified in each island flow system with the greatest potential for small-capacity water-supply development based on the model-calculated depth to water and surficial geology of the islands. Model-calculated depth to water estimates were used because of the lack of available hydrologic data for the islands. Model results indicate that the simulated depth to water is less than 20 feet within 240 feet from the shore of the hypothetical drumlin-island flow system. This area on the topographic maps of the six Boston Harbor Islands roughly coincides with the high transmissivity zones of stratified-beach deposits and weathered till on the lower slopes of the drumlins where ground-water discharge and surface and subsurface runoff occurs.</p>","language":"English","publisher":"U.S. Geological Survey","doi":"10.3133/ofr96117","usgsCitation":"Masterson, J., Stone, B.D., and Rendigs, R., 1996, Geohydrology and potential water-supply development on Bumkin, Gallops, Georges, Grape, Lovell, and Peddocks Islands, eastern Massachusetts: U.S. Geological Survey Open-File Report 96-117, iii, 22 p., https://doi.org/10.3133/ofr96117.","productDescription":"iii, 22 p.","costCenters":[{"id":40020,"text":"Florence Bascom Geoscience Center","active":true,"usgs":true}],"links":[{"id":53024,"rank":300,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0117/report.pdf","linkFileType":{"id":1,"text":"pdf"}},{"id":156815,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/of/1996/0117/report-thumb.jpg"}],"country":"United States","state":"Massachusetts","otherGeospatial":"Bumkin Island, Gallops Island, Georges Island, Grape Island, Lovells Island, Peddocks Island","geographicExtents":"{\n  \"type\": \"FeatureCollection\",\n  \"features\": [\n    {\n      \"type\": \"Feature\",\n      \"properties\": {},\n      \"geometry\": {\n        \"type\": \"Polygon\",\n        \"coordinates\": [\n          [\n            [\n              -70.94932079315186,\n              42.286611704476755\n            ],\n            [\n              -70.94605922698975,\n              42.286579956197585\n            ],\n            [\n              -70.9425401687622,\n              42.289119767970696\n            ],\n            [\n              -70.93756198883055,\n              42.2836907958173\n            ],\n            [\n              -70.93739032745361,\n              42.28537350973319\n            ],\n            [\n              -70.9390640258789,\n              42.28810385554954\n            ],\n            [\n              -70.93460083007811,\n              42.29302452881708\n            ],\n            [\n              -70.93262672424315,\n              42.295818030305995\n            ],\n            [\n              -70.92700481414795,\n              42.298230500058324\n            ],\n            [\n              -70.92563152313232,\n              42.300579394960764\n            ],\n            [\n              -70.92782020568848,\n              42.30305516230249\n            ],\n            [\n              -70.93408584594727,\n              42.303118642236306\n            ],\n            [\n              -70.93640327453613,\n              42.300008050211034\n            ],\n            [\n              -70.93554496765137,\n              42.29715124869881\n            ],\n            [\n              -70.93936443328857,\n              42.29343721297362\n            ],\n            [\n              -70.94361305236816,\n              42.291437256860554\n            ],\n            [\n              -70.9503936767578,\n              42.290992813544584\n            ],\n            [\n              -70.95065116882324,\n              42.29007217098532\n            ],\n            [\n              -70.94932079315186,\n              42.286611704476755\n            ]\n          ]\n        ]\n      }\n    },\n    {\n      \"type\": \"Feature\",\n      \"properties\": {},\n      \"geometry\": {\n        \"type\": \"Polygon\",\n        \"coordinates\": [\n          [\n            [\n              -70.92567443847656,\n              42.3179077219822\n            ],\n            [\n              -70.92520236968994,\n              42.319621253343435\n            ],\n            [\n              -70.92636108398438,\n              42.3220962718212\n            ],\n            [\n              -70.93082427978516,\n              42.32241357484161\n            ],\n            [\n              -70.93125343322754,\n              42.32104916050047\n            ],\n            [\n              -70.93138217926025,\n              42.31927220444314\n            ],\n            [\n              -70.92949390411377,\n              42.31746346549393\n            ],\n            [\n              -70.92803478240965,\n              42.31701920586935\n            ],\n            [\n              -70.92696189880371,\n              42.31774905931072\n            ],\n            [\n              -70.92567443847656,\n              42.3179077219822\n            ]\n          ]\n        ]\n      }\n    },\n    {\n      \"type\": \"Feature\",\n      \"properties\": {},\n      \"geometry\": {\n        \"type\": \"Polygon\",\n        \"coordinates\": [\n          [\n            [\n              -70.93966484069824,\n              42.324253900804166\n            ],\n            [\n              -70.93344211578369,\n              42.32625281456479\n            ],\n            [\n              -70.93361377716063,\n              42.32660182474028\n            ],\n            [\n              -70.93734741210938,\n              42.326982560905236\n            ],\n            [\n              -70.94133853912354,\n              42.328061300858955\n            ],\n            [\n              -70.94266891479492,\n              42.3269508329795\n            ],\n            [\n              -70.94035148620605,\n              42.324317359359995\n            ],\n            [\n              -70.93966484069824,\n              42.324253900804166\n            ]\n          ]\n        ]\n      }\n    },\n    {\n      \"type\": \"Feature\",\n      \"properties\": {},\n      \"geometry\": {\n        \"type\": \"Polygon\",\n        \"coordinates\": [\n          [\n            [\n              -70.92339992523193,\n              42.325269230016424\n            ],\n            [\n              -70.92275619506836,\n              42.32637972757989\n            ],\n            [\n              -70.92962265014648,\n              42.33342299848599\n            ],\n            [\n              -70.92962265014648,\n              42.334025764313395\n            ],\n            [\n              -70.9309959411621,\n              42.33386714228732\n            ],\n            [\n              -70.93258380889893,\n              42.33282022688166\n            ],\n            [\n              -70.93138217926025,\n              42.33167811747311\n            ],\n            [\n              -70.93189716339111,\n              42.3288544801997\n            ],\n            [\n              -70.93146800994873,\n              42.32831511933613\n            ],\n            [\n              -70.92988014221191,\n              42.32837857379541\n            ],\n            [\n              -70.92704772949217,\n              42.32723638373504\n            ],\n            [\n              -70.92623233795166,\n              42.32574515994394\n            ],\n            [\n              -70.92533111572266,\n              42.32517404359888\n            ],\n            [\n              -70.92339992523193,\n              42.325269230016424\n            ]\n          ]\n        ]\n      }\n    },\n    {\n      \"type\": \"Feature\",\n      \"properties\": {},\n      \"geometry\": {\n        \"type\": \"Polygon\",\n        \"coordinates\": [\n          [\n            [\n              -70.89503288269043,\n              42.28003946955424\n            ],\n            [\n              -70.89687824249268,\n              42.28178578242755\n            ],\n            [\n              -70.90142726898193,\n              42.28283354691986\n            ],\n            [\n              -70.90370178222655,\n              42.28140477283768\n            ],\n            [\n              -70.90297222137451,\n              42.28026173024424\n            ],\n            [\n              -70.90018272399902,\n              42.279626697621374\n            ],\n            [\n              -70.89640617370605,\n              42.27940443469142\n            ],\n            [\n              -70.89503288269043,\n              42.28003946955424\n            ]\n          ]\n        ]\n      }\n    },\n    {\n      \"type\": \"Feature\",\n      \"properties\": {},\n      \"geometry\": {\n        \"type\": \"Polygon\",\n        \"coordinates\": [\n          [\n            [\n              -70.92041730880737,\n              42.267512225001596\n            ],\n            [\n              -70.92003107070923,\n              42.26824265235251\n            ],\n            [\n              -70.91897964477539,\n              42.2684490759395\n            ],\n            [\n              -70.91816425323485,\n              42.26894131407298\n            ],\n            [\n              -70.91711282730103,\n              42.26875077073535\n            ],\n            [\n              -70.91636180877686,\n              42.27054503100655\n            ],\n            [\n              -70.91797113418579,\n              42.27202168477405\n            ],\n            [\n              -70.91973066329956,\n              42.27157710448389\n            ],\n            [\n              -70.92185497283936,\n              42.27052915282104\n            ],\n            [\n              -70.92556715011597,\n              42.269798751964686\n            ],\n            [\n              -70.92618942260742,\n              42.26883016386268\n            ],\n            [\n              -70.92554569244385,\n              42.26762337753574\n            ],\n            [\n              -70.92329263687134,\n              42.26728991934532\n            ],\n            [\n              -70.92041730880737,\n              42.267512225001596\n            ]\n          ]\n        ]\n      }\n    }\n  ]\n}","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1be4b07f02db6a8c92","contributors":{"authors":[{"text":"Masterson, John P. 0000-0003-3202-4413","orcid":"https://orcid.org/0000-0003-3202-4413","contributorId":102516,"corporation":false,"usgs":true,"family":"Masterson","given":"John P.","affiliations":[{"id":466,"text":"New England Water Science Center","active":true,"usgs":true}],"preferred":false,"id":190773,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Stone, Byron D. 0000-0001-6092-0798 bdstone@usgs.gov","orcid":"https://orcid.org/0000-0001-6092-0798","contributorId":1702,"corporation":false,"usgs":true,"family":"Stone","given":"Byron","email":"bdstone@usgs.gov","middleInitial":"D.","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":190772,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Rendigs, R.R.","contributorId":50506,"corporation":false,"usgs":true,"family":"Rendigs","given":"R.R.","affiliations":[],"preferred":false,"id":190771,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}}
,{"id":23428,"text":"ofr96140 - 1996 - Science for a Sustainable Future of the Great Plains: Water-Quality Assessment in Central Nebraska","interactions":[],"lastModifiedDate":"2012-02-02T00:08:14","indexId":"ofr96140","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-140","title":"Science for a Sustainable Future of the Great Plains: Water-Quality Assessment in Central Nebraska","language":"ENGLISH","publisher":"U.S. Geological Survey","doi":"10.3133/ofr96140","issn":"0094-9140","usgsCitation":"Huntzinger, T.L., and Stamer, J.K., 1996, Science for a Sustainable Future of the Great Plains: Water-Quality Assessment in Central Nebraska: U.S. Geological Survey Open-File Report 96-140, 1 sheet :col. ill., col. maps ;43 x 28 cm. folded to 22 x 28 cm., https://doi.org/10.3133/ofr96140.","productDescription":"1 sheet :col. ill., col. maps ;43 x 28 cm. folded to 22 x 28 cm.","costCenters":[{"id":595,"text":"U.S. Geological Survey","active":false,"usgs":true}],"links":[{"id":156967,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":13212,"rank":300,"type":{"id":11,"text":"Document"},"url":"https://ne.water.usgs.gov/Nawqa/pubs/OFR-96-140.pdf","linkFileType":{"id":1,"text":"pdf"}}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a0de4b07f02db5fd3b0","contributors":{"authors":[{"text":"Huntzinger, Thomas L.","contributorId":104054,"corporation":false,"usgs":true,"family":"Huntzinger","given":"Thomas","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":190085,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Stamer, John K.","contributorId":104481,"corporation":false,"usgs":true,"family":"Stamer","given":"John","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":190086,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":49815,"text":"ofr96387 - 1996 - Level II scour analysis for Bridge 36 (BRIDTH00050036) on Town Highway 5, crossing Bridgewater Hollow Brook, Bridgewater, Vermont","interactions":[],"lastModifiedDate":"2013-12-10T14:46:43","indexId":"ofr96387","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-387","title":"Level II scour analysis for Bridge 36 (BRIDTH00050036) on Town Highway 5, crossing Bridgewater Hollow Brook, Bridgewater, Vermont","docAbstract":"<p>This report provides the results of a detailed Level II analysis of scour potential at structure \nBRIDTH00050036 on town highway 5 crossing Bridgewater Hollow Brook, Bridgewater, \nVermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including \na quantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.</p>\n<br/>\n<p>The site is in the Green Mountain section of the New England physiographic province of \ncentral Vermont. The 3.60-mi<sup>2</sup>\n drainage area is in a predominantly forested basin. In the \nvicinity of the study site, the banks have dense woody vegetation coverage.</p>\n<br/>\n<p>In the study area, Bridgewater Hollow Brook has an incised, sinuous channel with a slope \nof approximately 0.028 ft/ft, an average channel top width of 24 ft and an average channel \ndepth of 4 ft. The predominant channel bed material is cobble (D<sub>50</sub> is 196 mm or 0.644 ft). \nThe geomorphic assessment at the time of the Level I and Level II site visit on November 2, \n1994, indicated that the reach was stable.</p>\n<br/>\n<p>The town highway 5 crossing of Bridgewater Hollow Brook is a 30-ft-long, one-lane bridge \nconsisting of one 27-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, August 25, 1994). The bridge is supported by vertical, concrete abutments \nwith wingwalls. The channel is skewed approximately 30 degrees to the opening and the \nopening-skew-to-roadway is also 30 degrees. </p>\n<br/>\n<p>The scour protection measures at this site were sparse type-2 stone fill (less than 36 inches \ndiameter) along both abutments, upstream wingwalls, and the downstream left wingwall \nand type-1 stone fill (less than 12 inches diameter) along the downstream right wingwall.\nAdditional details describing conditions at the site are included in the Level II Summary \nand Appendices D and E.</p>\n<br/>\n<p>Scour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a \nhighway crossing is comprised of three components: 1) long-term streambed degradation; \n2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) \nand; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is \nthe sum of the three components. Equations are available to compute depths for contraction \nand local scour and a summary of the results of these computations follows.</p>\n<br/>\n<p>There was no contraction scour for all modelled flows. Abutment scour ranged from 4.9 to \n7.0 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution. </p>\n<br/>\n<p>It 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.</p>","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96387","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Olson, S.A., and Boehmler, E.M., 1996, Level II scour analysis for Bridge 36 (BRIDTH00050036) on Town Highway 5, crossing Bridgewater Hollow Brook, Bridgewater, Vermont: U.S. Geological Survey Open-File Report 96-387, iv, 30 p., https://doi.org/10.3133/ofr96387.","productDescription":"iv, 30 p.","numberOfPages":"35","costCenters":[],"links":[{"id":178614,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96387.GIF"},{"id":279353,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0387/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Bridgewater","otherGeospatial":"Bridgewater Hollow Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.625 ], [ -72.75,43.75 ], [ -72.625,43.75 ], [ -72.625,43.625 ], [ -72.75,43.625 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a6446","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":240309,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240310,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":49832,"text":"ofr96566 - 1996 - Level II scour analysis for Bridge 96 (BLOOVT01050096) on Vermont Route 105, crossing Nulhegan River, Bloomfield, Vermont","interactions":[],"lastModifiedDate":"2013-12-10T13:38:00","indexId":"ofr96566","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-566","title":"Level II scour analysis for Bridge 96 (BLOOVT01050096) on Vermont Route 105, crossing Nulhegan River, Bloomfield, Vermont","docAbstract":"<p>This report provides the results of a detailed Level II analysis of scour potential at structure BLOOVT01050096 on Vermont Route 105 crossing the Nulhegan River, Bloomfield, 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.</p>\n<br/>\n<p>The site is in the White Mountain section of the New England physiographic province of north-east Vermont in the town of Bloomfield. The 103-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is shrub and brushland upstream. Downstream of the bridge, the surface cover is forest.</p>\n<br/>\n<p>In the study area, the Nulhegan River has an incised, sinuous channel with a slope of approximately 0.015 ft/ft, an average channel top width of 78 ft and an average channel depth of 5 ft. The predominant channel bed material is cobble with a median grain size (D50) of 133 mm (0.435 ft). About 100 feet upstream, the streambed and bank materials abruptly change predominantly to sand. The geomorphic assessment at the time of the Level I and Level II site visit on July 6, 1995, indicated that the upstream reach, which is experiencing channel scour and severe bank cutting into the alluvial channel boundaries, is not stable. The downstream reach is semi- to non-alluvial and is assessed as stable.</p>\n<br/>\n<p>The Vermont Route 105 crossing of the Nulhegan River is a 74-ft-long, two-lane bridge consisting of one 71-foot steel stringer type superstructure with a concrete deck (Vermont Agency of Transportation, written communication, August 5, 1994). 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 25 degrees.</p>\n<br/>\n<p>A scour hole 4.0 ft deeper than the mean thalweg depth was observed along the upstream channel during the Level I assessment. Scour protection measures at the site consist of type-2 stone fill (less than 24 inches diameter) along the entire base length of both abutments and all wingwalls. Additional details describing conditions at the site are included in the Level II Summary and Appendices D\nand E.</p>\n<br/>\n<p>Scour depths and 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.</p>\n<br/>\n<p>Contraction scour for all modelled flows ranged from 0.5 to 1.1 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 10.5 to 16.2 ft. The worst-case abutment 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.</p>\n<br/>\n<p>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.</p>","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96566","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ayotte, J., and Ivanoff, M.A., 1996, Level II scour analysis for Bridge 96 (BLOOVT01050096) on Vermont Route 105, crossing Nulhegan River, Bloomfield, Vermont: U.S. Geological Survey Open-File Report 96-566, iv, 48 p., https://doi.org/10.3133/ofr96566.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":162556,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96566.PNG"},{"id":279295,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0566/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Bloomfield","otherGeospatial":"Nulhegan River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -71.75,44.75 ], [ -71.75,44.875 ], [ -71.625,44.875 ], [ -71.625,44.75 ], [ -71.75,44.75 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b16e4b07f02db6a559d","contributors":{"authors":[{"text":"Ayotte, Joseph D. jayotte@usgs.gov","contributorId":1802,"corporation":false,"usgs":true,"family":"Ayotte","given":"Joseph D.","email":"jayotte@usgs.gov","affiliations":[{"id":466,"text":"New England Water Science Center","active":true,"usgs":true}],"preferred":false,"id":240336,"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":240337,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":49854,"text":"ofr96644 - 1996 - Level II scour analysis for Bridge 31 (HARDTH00050031) on Town Highway 5, crossing the Lamoille River, Hardwick, Vermont","interactions":[],"lastModifiedDate":"2013-11-20T14:42:57","indexId":"ofr96644","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-644","title":"Level II scour analysis for Bridge 31 (HARDTH00050031) on Town Highway 5, crossing the Lamoille River, Hardwick, Vermont","language":"ENGLISH","doi":"10.3133/ofr96644","usgsCitation":"Olson, S., 1996, Level II scour analysis for Bridge 31 (HARDTH00050031) on Town Highway 5, crossing the Lamoille River, Hardwick, Vermont: U.S. Geological Survey Open-File Report 96-644, 50 p., https://doi.org/10.3133/ofr96644.","productDescription":"50 p.","costCenters":[],"links":[{"id":162282,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":279271,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0644/report.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b19e4b07f02db6a7eb3","contributors":{"authors":[{"text":"Olson, S.A.","contributorId":58681,"corporation":false,"usgs":true,"family":"Olson","given":"S.A.","email":"","affiliations":[],"preferred":false,"id":240369,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
,{"id":24746,"text":"ofr96477 - 1996 - U.S. Geological Survey Nitrogen-Cycling Workshop: Denver, Colorado October 30 - November 2, 1995","interactions":[],"lastModifiedDate":"2019-12-07T09:44:58","indexId":"ofr96477","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-477","title":"U.S. Geological Survey Nitrogen-Cycling Workshop: Denver, Colorado October 30 - November 2, 1995","docAbstract":"<p>No abstract available.</p>","language":"English","publisher":" U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/ofr96477","issn":"0094-9140","usgsCitation":"Triska, F.J., 1996, U.S. Geological Survey Nitrogen-Cycling Workshop: Denver, Colorado October 30 - November 2, 1995: U.S. Geological Survey Open-File Report 96-477, 88 p., https://doi.org/10.3133/ofr96477.","productDescription":"88 p.","costCenters":[{"id":392,"text":"Minnesota Water Science Center","active":true,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":272566,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0477/report.pdf"},{"id":158186,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/of/1996/0477/report-thumb.jpg"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a2be4b07f02db6130e4","contributors":{"editors":[{"text":"Puckett, Larry J. lpuckett@usgs.gov","contributorId":31739,"corporation":false,"usgs":true,"family":"Puckett","given":"Larry J.","email":"lpuckett@usgs.gov","affiliations":[{"id":451,"text":"National Water Quality Assessment Program","active":true,"usgs":true}],"preferred":false,"id":749341,"contributorType":{"id":2,"text":"Editors"},"rank":1}],"authors":[{"text":"Triska, Frank J.","contributorId":88781,"corporation":false,"usgs":true,"family":"Triska","given":"Frank","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":192485,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
,{"id":49839,"text":"ofr96582 - 1996 - Level II scour analysis for Bridge 32 (CONCTH00030032) on Town Highway 3, crossing the Moose River, Concord, Vermont","interactions":[],"lastModifiedDate":"2013-12-05T16:07:22","indexId":"ofr96582","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-582","title":"Level II scour analysis for Bridge 32 (CONCTH00030032) on Town Highway 3, crossing the Moose River, Concord, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nCONCTH00030032 on Town Highway 3 crossing the Moose River, Concord, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.\nApproximately 85 percent of the drainage above the site is in the White Mountain section \nand 15 percent is in the New England Upland section of the New England physiographic \nprovince in northeastern Vermont. The 98.7-mi<sup>2</sup>\n drainage area is in a predominantly rural \nand forested basin. In the vicinity of the study site, the surface cover is primarily grass with \nseveral houses and other buildings while the immediate channel banks have dense woody \nvegetation.\nIn the study area, the Moose River has an incised, sinuous channel with a slope of \napproximately 0.01 ft/ft, an average channel top width of 83 ft and an average channel \ndepth of 3 ft. The predominant channel bed material is cobble with a median grain size \n(D<sub>50</sub>) of 86.2 mm (0.283 ft). There are bedrock exposures downstream of the bridge. The \ngeomorphic assessment at the time of the Level I and Level II site visit on August 17, 1995, \nindicated that the reach was stable.\nThe Town Highway 3 crossing of the Moose River is a 96-ft-long, two-lane bridge \nconsisting of two steel-beam spans (Vermont Agency of Transportation, written \ncommunication, March 24, 1995). The bridge is supported by vertical, concrete abutments \nwith wingwalls and a concrete pier. The channel is skewed approximately 10 degrees to the \nopening while the opening-skew-to-roadway is 0 degrees. \nThe right upstream end of the pier is undermined by 1.3 feet. The footing of the right \nabutment is exposed by as much as 4.0 feet vertically. The footing of the downstream right \nwingwall is exposed 3.5 feet and the end of the wingwall has broken and fallen into the \nriver. Type-3 stone fill (less than 48 inches diameter) has been placed at the end of the \nexisting wingwall. Additional details describing conditions at the site are included in the \nLevel II Summary and Appendices \nD and E.\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a \nhighway crossing is comprised of three components: 1) long-term streambed degradation; \n2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) \nand; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is \nthe sum of the three components. Equations are available to compute depths for contraction \nand local scour and a summary of the results of these computations follows.\nContraction scour for all modelled flows ranged from 0.0 to 0.7 ft. Abutment scour ranged \nfrom 9.9 to 16.4 ft. Pier scour ranged from 14.4 to 16.2 ft. The worst-case contraction, \nabutment, and pier scour occurred at the 500-year discharge. Additional information on \nscour depths and depths to armoring are included in the section titled “Scour Results”. \nScoured-streambed elevations, based on the calculated scour depths, are presented in tables \n1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour \ndepths were calculated assuming an infinite depth of erosive material and a homogeneous \nparticle-size distribution. \nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.","language":"English","publisher":"U.S. Geological Survey","doi":"10.3133/ofr96582","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Olson, S.A., 1996, Level II scour analysis for Bridge 32 (CONCTH00030032) on Town Highway 3, crossing the Moose River, Concord, Vermont: U.S. Geological Survey Open-File Report 96-582, iv, 51 p., https://doi.org/10.3133/ofr96582.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":162563,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96582.PNG"},{"id":279287,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0582/report.pdf"}],"country":"United States","state":"Vermont","city":"Concord","otherGeospatial":"Moose River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -71.933288,44.35054 ], [ -71.933288,44.505065 ], [ -71.738643,44.505065 ], [ -71.738643,44.35054 ], [ -71.933288,44.35054 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a7ee4b07f02db648627","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":240347,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
,{"id":49807,"text":"ofr96309 - 1996 - Level II scour analysis for Bridge 37 (BRIDTH00050037) on Town Highway 5, crossing North Branch Ottauquechee River, Bridgewater, Vermont","interactions":[],"lastModifiedDate":"2013-12-10T16:16:11","indexId":"ofr96309","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-309","title":"Level II scour analysis for Bridge 37 (BRIDTH00050037) on Town Highway 5, crossing North Branch Ottauquechee River, Bridgewater, Vermont","docAbstract":"<p>This report provides the results of a detailed Level II analysis of scour potential at structure \nBRIDTH00050037 on town highway 5 crossing the North Branch Ottauquechee River, \nBridgewater, 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). A Level I study is included in Appendix E of this report. A Level I \nstudy provides a qualitative geomorphic characterization of the study site. Information on \nthe bridge available from VTAOT files was compiled prior to conducting Level I and Level \nII analyses and can be found in Appendix D.</p>\n<br/>\n<p>The site is in the Green Mountain physiographic province of central Vermont in the town of \nBridgewater. The 10.5-mi<sup>2</sup>\n drainage area is a predominantly rural basin. In the vicinity of \nthe study site, the left and right banks are forested. Town highway 5 runs parallel to the \nupstream left and downstream right banks.</p>\n<br/>\n<p>In the study area, the North Branch Ottauquechee River has a sinuous channel with a slope \nof approximately 0.013 ft/ft, an average channel top width of 50 ft and an average channel \ndepth of 5 ft. The predominant channel bed materials are gravel and cobble (D<sub>50</sub> is 79.3 mm \nor 0.260 ft). The geomorphic assessment at the time of the Level I and Level II site visit on \nNovember 2, 1994, indicated that the reach was stable.</p>\n<br/>\n<p>The town highway 5 crossing of the North Branch Ottauquechee Riveris a 38-ft-long, onelane bridge consisting of one 35-foot steel beam span (Vermont Agency of Transportation, \nwritten commun., August 25, 1994). The bridge is supported by vertical, stone abutments \nwith wingwalls. The right abutment has settled due to scour. Type-3 stone fill (less than 36 \ninches diameter) provides protection to the upstream end of the upstream left wingwall and \nthe base of the downstream right wingwall. The channel is skewed approximately 35 \ndegrees; the opening-skew-to-roadway is 20 degrees. Additional details describing \nconditions at the site are included in the Level II Summary and Appendix E.</p>\n<br/>\n<p>Scour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1993). Total scour at a \nhighway crossing is comprised of three components: 1) long-term streambed degradation; \n2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) \nand; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is \nthe sum of the three components. Equations are available to compute depths for contraction \nand local scour and a summary of the results of these computations follows.</p>\n<br/>\n<p>Contraction scour for all modelled flows ranged from 0.4 to 1.5 ft. The worst-case \ncontraction scour occurred at the incipient overtopping discharge, which was less than the \n100-year discharge. Abutment scour ranged from 11.0 to 14.9 ft. 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. </p>\n<br/>\n<p>It is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1993, p. 48). Many factors, \nincluding historical performance during flood events, the geomorphic assessment, scour \nprotection measures, and the results of the hydraulic analyses, must be considered to \nproperly assess the validity of abutment scour results. Therefore, scour depths adopted by \nVTAOT may differ from the computed values documented herein, based on the \nconsideration of additional contributing factors and experienced engineering judgement.</p>","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96309","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Olson, S.A., and Ivanoff, M.A., 1996, Level II scour analysis for Bridge 37 (BRIDTH00050037) on Town Highway 5, crossing North Branch Ottauquechee River, Bridgewater, Vermont: U.S. Geological Survey Open-File Report 96-309, iv, 30 p., https://doi.org/10.3133/ofr96309.","productDescription":"iv, 30 p.","numberOfPages":"35","costCenters":[],"links":[{"id":179406,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96309.GIF"},{"id":279374,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0309/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Bridgewater","otherGeospatial":"North Branch Ottauquechee River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.625 ], [ -72.75,43.75 ], [ -72.625,43.75 ], [ -72.625,43.625 ], [ -72.75,43.625 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a635c","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":240293,"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":240294,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":49774,"text":"ofr96159 - 1996 - Level II scour analysis for Bridge 22 (WODSTH00180022) on Town Highway 18, crossing north Bridgewater Brook, Woodstock, Vermont","interactions":[],"lastModifiedDate":"2013-12-12T11:30:09","indexId":"ofr96159","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-159","title":"Level II scour analysis for Bridge 22 (WODSTH00180022) on Town Highway 18, crossing north Bridgewater Brook, Woodstock, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nWODSTH00180022 on town highway 18 crossing North Bridgewater Brook, Woodstock, \nVermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including \na quantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). A Level I study is included in Appendix E of this report. A Level I study provides \na qualitative geomorphic characterization of the study site. Information on the bridge, \navailable from VTAOT files, was compiled prior to conducting Level I and Level II \nanalyses and can be found in Appendix D.\nThe site is in the Green Mountain physiographic province of central Vermont. The 4.34-mi<sup>2</sup>\ndrainage area is in a predominantly rural and forested basin. In the vicinity of the study site, \nthe left bank is forested and the right bank is covered by shrub and brush and is adjacent to \nwoods. The right bank of North Bridgewater Brook is parallel to town highway 18 \nupstream of the bridge.\nIn the study area, North Bridgewater Brook has a sinuous channel with a slope of \napproximately 0.038 ft/ft, an average channel top width of 48 ft and an average channel \ndepth of 7 ft. The predominant channel bed materials are gravel and cobbles (D<sub>50</sub> is 63.2 \nmm or 0.207 ft). Due to cut banks and other channel features the geomorphic assessment at \nthe time of the Level I and Level II site visit on August 16, 1994, indicated that the reach \nwas laterally unstable. In addition, the stream approach to the bridge has a high gradient. \nHowever, near the upstream face of the bridge the gradient shallows. Approximately 100 \nfeet downstream of the bridge the gradient steepens again.\nThe town highway 18 crossing of North Bridgewater Brook is a 40-ft-long, two-lane bridge \nconsisting of one 35-foot concrete span (Vermont Agency of Transportation, written \ncommun., August 2, 1994). The bridge is supported by vertical, concrete abutments with \nwingwalls. The left and right abutments are not protected by stone fill. Additional details \ndescribing conditions at the site are included in the Level II Summary and Appendices D \nand E.\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1993). Scour depths were \ncalculated assuming an infinite depth of erosive material and a homogeneous particle-size \ndistribution. The scour analysis results are presented in tables 1 and 2 and a graph of the \nscour depths is presented in figure 8.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, New Hampshire","doi":"10.3133/ofr96159","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Olson, S.A., 1996, Level II scour analysis for Bridge 22 (WODSTH00180022) on Town Highway 18, crossing north Bridgewater Brook, Woodstock, Vermont: U.S. Geological Survey Open-File Report 96-159, iv, 28 p., https://doi.org/10.3133/ofr96159.","productDescription":"iv, 28 p.","numberOfPages":"33","costCenters":[],"links":[{"id":179329,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96159.PNG"},{"id":279422,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0159/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Woodstock","otherGeospatial":"Bridgewater Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.625,43.625 ], [ -72.625,43.75 ], [ -72.5,43.75 ], [ -72.5,43.625 ], [ -72.625,43.625 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a810e","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":240240,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
,{"id":49773,"text":"ofr96158 - 1996 - Level II scour analysis for Bridge 22 (CRAFTH00180022) on Town Highway 18, crossing Black River, Craftsbury, Vermont","interactions":[],"lastModifiedDate":"2013-12-12T11:41:04","indexId":"ofr96158","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-158","title":"Level II scour analysis for Bridge 22 (CRAFTH00180022) on Town Highway 18, crossing Black River, Craftsbury, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nCRAFTH00180022 on town highway 18 crossing the Black River, Craftsbury, 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). A Level I study is included in Appendix E of this report. A Level I study provides \na qualitative geomorphic characterization of the study site. Information on the bridge, \navailable from VTAOT files, was compiled prior to conducting Level I and Level II \nanalyses and can be found in Appendix D.\nThe site is in the New England Upland physiographic province of north-central Vermont in \nthe town of Craftsbury. The 41.6-mi<sup>2</sup>\n drainage area is in a predominantly rural and forested\nbasin. In the vicinity of the study site, the banks and floodplains are pasture and have no \nwoody vegetation coverage.\nIn the study area, the Black River is not incised, has a meandering channel with a slope of \napproximately 0.0004 ft/ft, an average channel top width of 66 ft, and an average channel \ndepth of 3 ft. The predominant channel bed material is sand (D<sub>50</sub> is 0.148 mm or 0.000487\nft). The geomorphic assessment at the time of the Level I and Level II site visit on June 13, \n1995, indicated that the reach was laterally unstable.\nThe town highway 18 crossing of the Black Riveris a 60-ft-long, one-lane bridge consisting \nof one 55-foot clear-span riveted through-girder type structure with a timber deck (Vermont \nAgency of Transportation, written commun., August 3, 1994). The bridge is supported by \nconcrete abutments with no wingwalls. The bridge skew is approximately 5 degrees and \nthere is no opening-skew-to-roadway. \nA scour hole 3 ft deeper than the mean thalweg depth was observed 35 ft downstream of the \nbridge during the Level I assessment. There is also approximately 2 ft of channel scour \nupstream of the bridge. There is type-one (less than 12 in diameter) protection on both \nabutments that may act, in part, as spill-through abutments; the material however is partially \nmade up of the remnants of older log-cribbing abutments, when the bridge length was \nsignificantly less than the current structure. Additional details describing conditions at the \nsite are included in the Level II Summary and Appendices D and E.\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1993). Scour depths were \ncalculated assuming an infinite depth of erosive material and a homogeneous particle-size \ndistribution. The scour analysis results are presented in tables 1 and 2 and a graph of the \nscour depths is presented in figure 8.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96158","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ayotte, J., 1996, Level II scour analysis for Bridge 22 (CRAFTH00180022) on Town Highway 18, crossing Black River, Craftsbury, Vermont: U.S. Geological Survey Open-File Report 96-158, iv, 31 p., https://doi.org/10.3133/ofr96158.","productDescription":"iv, 31 p.","numberOfPages":"36","costCenters":[],"links":[{"id":179328,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96158.PNG"},{"id":279423,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0158/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Craftsbury","otherGeospatial":"Black River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -77.5,44.625 ], [ -77.5,44.75 ], [ -72.375,44.75 ], [ -72.375,44.625 ], [ -77.5,44.625 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8153","contributors":{"authors":[{"text":"Ayotte, Joseph D. jayotte@usgs.gov","contributorId":1802,"corporation":false,"usgs":true,"family":"Ayotte","given":"Joseph D.","email":"jayotte@usgs.gov","affiliations":[{"id":466,"text":"New England Water Science Center","active":true,"usgs":true}],"preferred":false,"id":240239,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
,{"id":49772,"text":"ofr96157 - 1996 - Level II scour analysis for Bridge 26 (BRIDTH00340026) on Town Highway 034, crossing Ottauquechee River, Bridgewater, Vermont","interactions":[],"lastModifiedDate":"2013-12-12T11:48:50","indexId":"ofr96157","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-157","title":"Level II scour analysis for Bridge 26 (BRIDTH00340026) on Town Highway 034, crossing Ottauquechee River, Bridgewater, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nBRIDTH00340026 on town highway 34 crossing the Ottauquechee River, Bridgewater, \nVermont (figures 1–8). A Level II study is a basic engineering analysis of the site, \nincluding a quantitative analysis of stream stability and scour (U.S. Department of \nTransportation, 1993). A Level I study is included in Appendix E of this report. A Level \nI study provides a qualitative geomorphic characterization of the study site. Information on \nthe bridge available from VTAOT files were compiled prior to conducting Level I and \nLevel II analyses and can be found in Appendix D.\nThe site is in the Green Mountain physiographic province of central Vermont in the town of \nBridgewater. The 38.0-mi<sup>2</sup>\n drainage area is in a predominantly rural and forested basin. In \nthe vicinity of the study site, the banks have dense woody vegetation coverage except for \nthe upstream right bank, which is grass covered.\nIn the study area, the Ottauquechee River has an incised, sinuous channel with a slope of \napproximately 0.01 ft/ft, an average channel top width of 62.5 ft and an average channel \ndepth of 4.5 ft. The predominant channel bed material is cobble (D<sub>50</sub> is 97.3 mm or 0.319\nft). The geomorphic assessment at the time of the Level I and Level II site visit on \nNovember 8, 1994, indicated that the reach was stable.\nThe town highway 34 crossing of the Ottauquechee Riveris a 69-ft-long, two-lane bridge \nconsisting of one 63-foot clear-span steel-pony truss-type superstructure (Vermont Agency \nof Transportation, written commun., August 24, 1994). The bridge is supported by vertical, \nconcrete abutments with wingwalls. The channel is skewed approximately 40 degrees to the \nopening while the opening-skew-to-roadway is 45 degrees. \nA scour hole 4.5 ft deeper than the mean thalweg depth was observed along the upstream \nleft wingwall during the Level I assessment. The only scour protection measure at the site \nwas type-1 stone fill (less than 12 inches diameter) at the upstream end of the upstream left \nwingwall. Additional details describing conditions at the site are included in the Level II \nSummary and Appendices D \nand E.\nScour depths were computed using the general guidelines described in Hydraulic \nEngineering Circular 18 (Richardson and others, 1993). These guidelines provide scour \nequations, which assume an infinite depth of erosive material and a homogeneous particle-size distribution. The scour analysis results are presented in tables 1 and 2 and a graph of \nthe scour depths is presented in figure 8.","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96157","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Boehmler, E.M., 1996, Level II scour analysis for Bridge 26 (BRIDTH00340026) on Town Highway 034, crossing Ottauquechee River, Bridgewater, Vermont: U.S. Geological Survey Open-File Report 96-157, iv, 31 p., https://doi.org/10.3133/ofr96157.","productDescription":"iv, 31 p.","numberOfPages":"36","costCenters":[],"links":[{"id":179327,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96157.PNG"},{"id":279424,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0157/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Bridgewater","otherGeospatial":"Ottauquechee 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":"4f4e4b1ae4b07f02db6a8154","contributors":{"authors":[{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240238,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
,{"id":49769,"text":"ofr96154 - 1996 - Level II scour analysis for Bridge 20 (IRASTH00080020) on Town Highway 8, crossing the Black River, Irasburg, Vermont","interactions":[],"lastModifiedDate":"2014-01-09T11:51:56","indexId":"ofr96154","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-154","title":"Level II scour analysis for Bridge 20 (IRASTH00080020) on Town Highway 8, crossing the Black River, Irasburg, Vermont","docAbstract":"<p>This report provides the results of a detailed Level II analysis of scour potential at structure \nIRASTH00080020 on town highway 8 crossing the Black River, Irasburg, 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). A Level I study is included in Appendix E of this report. A Level I study provides \na qualitative geomorphic characterization of the study site. Information on the bridge, \navailable from VTAOT files, was compiled prior to conducting Level I and Level II \nanalyses and can be found in Appendix D.</p>\n<br/>\n<p>The site is in the New England Upland physiographic province of north-central Vermont in \nthe town of Irasburg. The 110-mi<sup>2</sup>\n drainage area is in a predominantly rural basin. In the \nvicinity of the study site, the left bank surface cover is pasture and row crops and the right \nbank is covered by shrub and brush and is adjacent to woods.</p>\n<br/>\n<p>In the study area, the Black River has a sinuous channel with a slope of approximately \n0.002 ft/ft, an average channel top width of 90 ft and an average channel depth of 5 ft. The \npredominant channel bed material is gravel and cobbles (D<sub>50</sub> is 49.7 mm or 0.163 ft). The \ngeomorphic assessment at the time of the Level I and Level II site visit on October 4, 1994, \nindicated that the reach was laterally unstable.</p>\n<br/>\n<p>The town highway 8 crossing of the Black River is a 88-ft-long, one-lane covered bridge \nconsisting of one 80-foot span (Vermont Agency of Transportation, written commun., \nAugust 2, 1994). The bridge is supported by vertical, concrete abutments with wingwalls on \nthe upstream and downstream sides of the right abutment. The right abutment has stone fill \nprotection. The channel is skewed approximately 25 degrees to the opening while the \nopening-skew-to-roadway is zero degrees. Additional details describing conditions at the \nsite are included in the Level II Summary and Appendices D and E.</p>\n<br/>\n<p>Scour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1993). Scour depths were \ncalculated assuming an infinite depth of erosive material and a homogeneous particle-size \ndistribution. The scour analysis results are presented in tables 1 and 2 and a graph of the \nscour depths is presented in figure 8.</p>","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96154","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Olson, S.A., 1996, Level II scour analysis for Bridge 20 (IRASTH00080020) on Town Highway 8, crossing the Black River, Irasburg, Vermont: U.S. Geological Survey Open-File Report 96-154, iv, 28 p., https://doi.org/10.3133/ofr96154.","productDescription":"iv, 28 p.","numberOfPages":"33","costCenters":[],"links":[{"id":176852,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96154.PNG"},{"id":279427,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0154/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Irasburg","otherGeospatial":"Black River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.375,44.75 ], [ -72.375,44.875 ], [ -72.25,44.875 ], [ -72.25,44.75 ], [ -72.375,44.75 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8023","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":240235,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
,{"id":49796,"text":"ofr96241 - 1996 - Level II scour analysis for Bridge 45 (CHELTH00440045) on Town Highway 44, crossing first Branch White River, Chelsea, Vermont","interactions":[],"lastModifiedDate":"2013-12-11T11:07:51","indexId":"ofr96241","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-241","title":"Level II scour analysis for Bridge 45 (CHELTH00440045) on Town Highway 44, crossing first Branch White River, Chelsea, Vermont","docAbstract":"<p>This report provides the results of a detailed Level II analysis of scour potential at structure \nCHELTH00440045 on town highway 44 crossing the First Branch White River, Chelsea, \nVermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including \na quantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). A Level I study is included in Appendix E of this report. A Level I study provides \na qualitative geomorphic characterization of the study site. Information on the bridge \navailable from VTAOT files was compiled prior to conducting Level I and Level II \nanalyses and can be found in Appendix D.</p>\n<br/>\n<p>The site is in the Green Mountain physiographic province of central Vermont in the town of \nChelsea. The 32.5-mi<sup>2</sup>\n drainage area is in a predominantly rural and forested basin. In the \nvicinity of the study site, the banks have low to moderate woody vegetation coverage except \nfor the upstream right bank, which is grass covered. The immediate vicinity of the site is \nsuburban and the overbank areas are occupied by houses, driveways, and lawn areas. The \nupstream right bank area is a dirt parking lot for a small auto repair garage.</p>\n<br/>\n<p>In the study area, the First Branch White River has an incised, sinuous channel with a slope \nof approximately 0.003 ft/ft, an average channel top width of 41 ft and an average channel \ndepth of 4 ft. The predominant channel bed material is gravel (D<sub>50</sub> is 43.1 mm or 0.141 ft). \nThe geomorphic assessment at the time of the Level I and Level II site visit on November \n17, 1994, indicated that the reach was stable.</p>\n<br/>\n<p>The town highway 44 crossing of the First Branch White Riveris a 31-ft-long, two-lane\nbridge consisting of one 27-foot clear-span concrete-encased steel beam deck \nsuperstructure (Vermont Agency of Transportation, written commun., August 25, 1994). \nThe bridge is supported by vertical, concrete abutments with wingwalls. The channel is \nskewed approximately 10 degrees to the opening while the opening-skew-to-roadway is 5 \ndegrees. </p>\n<br/>\n<p>Both abutment footings were reported as exposed and the left abutment was reported to be \nundermined by 0.5 ft at the time of the Level I assessment. The only scour protection \nmeasure at the site was type-1 stone fill (less than 12 inches diameter) along the left \nabutment which was reported as failed. Additional details describing conditions at the site \nare included in the Level II Summary and Appendices D and E.</p>\n<br/>\n<p>Scour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1993). Total scour at a \nhighway crossing is comprised of three components: 1) long-term streambed degradation; \n2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) \nand; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is \nthe sum of the three components. Equations are available to compute depths for contraction \nand local scour and a summary of the results of these computations follows.</p>\n<br/>\n<p>Contraction scour for all modelled flows ranged from 0.4 to 5.1 ft. with the worst-case \noccurring at the 500-year discharge. Abutment scour ranged from 9.9 to 20.3 ft. The worst-case abutment scour also occurred at the 500-year discharge. Additional information on \nscour depths and depths to armoring are included in the section titled “Scour Results”. \nScoured-streambed elevations, based on the calculated scour depths, are presented in tables \n1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour \ndepths were calculated assuming an infinite depth of erosive material and a homogeneous \nparticle-size distribution. </p>\n<br/>\n<p>It is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1993, p. 48). Many factors, \nincluding historical performance during flood events, the geomorphic assessment, scour \nprotection measures, and the results of the hydraulic analyses, must be considered to \nproperly assess the validity of abutment scour results. Therefore, scour depths adopted by \nVTAOT may differ from the computed values documented herein, based on the \nconsideration of additional contributing factors and experienced engineering judgement.</p>","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96241","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ayotte, J., and Hammond, R.E., 1996, Level II scour analysis for Bridge 45 (CHELTH00440045) on Town Highway 44, crossing first Branch White River, Chelsea, Vermont: U.S. Geological Survey Open-File Report 96-241, iv, 31 p., https://doi.org/10.3133/ofr96241.","productDescription":"iv, 31 p.","numberOfPages":"36","costCenters":[],"links":[{"id":179184,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96241.GIF"},{"id":279386,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0241/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Chelsea","otherGeospatial":"First Branch White River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.5,43.875 ], [ -72.5,44.0 ], [ -72.375,44.0 ], [ -72.375,43.875 ], [ -72.5,43.875 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a611f","contributors":{"authors":[{"text":"Ayotte, Joseph D. jayotte@usgs.gov","contributorId":1802,"corporation":false,"usgs":true,"family":"Ayotte","given":"Joseph D.","email":"jayotte@usgs.gov","affiliations":[{"id":466,"text":"New England Water Science Center","active":true,"usgs":true}],"preferred":false,"id":240273,"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":240274,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":49822,"text":"ofr96405 - 1996 - Level II scour analysis for Bridge 37 (BARTTH00080037) on Town Highway 8, crossing Willoughby River, Barton, Vermont","interactions":[],"lastModifiedDate":"2013-12-10T14:23:31","indexId":"ofr96405","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-405","title":"Level II scour analysis for Bridge 37 (BARTTH00080037) on Town Highway 8, crossing Willoughby River, Barton, Vermont","docAbstract":"<p>This report provides the results of a detailed Level II analysis of scour potential at structure \nBARTTH00080037 on town highway 8 crossing the Willoughby River, Barton, 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.</p>\n<br/>\n<p>The site is in the New England Upland section of the New England physiographic province\nof north-central Vermont in the town of Barton. The 60.4-mi<sup>2</sup>\n drainage area is in a \npredominantly rural and forested basin. In the vicinity of the study site, the banks have \nsparse to moderate woody vegetation coverage.</p>\n<br/>\n<p>In the study area, the Willoughby River is probably incised, has a sinuous channel with a \nslope of approximately 0.009 ft/ft, an average channel top width of 108 ft and an average \nchannel depth of 6 ft. The predominant channel bed material is cobble (D<sub>50</sub> is 95.1 mm or \n0.312 ft). The geomorphic assessment at the time of the Level I and Level II site visit on \nOctober 20, 1994, indicated that the reach was stable.</p>\n<br/>\n<p>The town highway 8 crossing of the Willoughby River is a 96-ft-long, two-lane bridge \nconsisting of one 94-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, August 4, 1994). The bridge is supported by vertical, concrete abutments \nwith wingwalls. The channel is skewed approximately 15 degrees to the opening while the \nopening-skew-to-roadway is 10 degrees. </p>\n<br/>\n<p>No scour was reported in the channel or along abutments or wingwalls during the Level I \nassessment. Type-2 stone fill (less than 24 inches diameter) was reported at each abutment \nand all four wingwalls. Additional details describing conditions at the site are included in \nthe Level II Summary and Appendices D and E.</p>\n<br/>\n<p>Scour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1993). Scour depths were \ncalculated assuming an infinite depth of erosive material and a homogeneous particle-size \ndistribution. Data in appendix D (Vermont Agency of Transportation, written \ncommunication, August 4, 1994) indicate that the right abutment may be founded on or near \nmarble bedrock which may limit scour depths. Bedrock was not detected by borings in the \nvicinity of the left abutment. The scour analysis results are presented in tables 1 and 2 and a \ngraph of the scour depths is presented in figure 8.</p>\n<br/>\n<p>Contraction scour for all modelled flows was 0 ft. Abutment scour ranged from 7.3 to 10.7 \nft and the worst-case abutment scour occurred at the 500-year discharge. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution. </p>\n<br/>\n<p>It is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1993, 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.</p>","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96405","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ayotte, J., and Boehmler, E.M., 1996, Level II scour analysis for Bridge 37 (BARTTH00080037) on Town Highway 8, crossing Willoughby River, Barton, Vermont: U.S. Geological Survey Open-File Report 96-405, iv, 48 p., https://doi.org/10.3133/ofr96405.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":178733,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96405.PNG"},{"id":279344,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0405/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Barton","otherGeospatial":"Willoughby River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.25,44.75 ], [ -72.25,44.875 ], [ -72.125,44.875 ], [ -72.125,44.75 ], [ -72.25,44.75 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a63bb","contributors":{"authors":[{"text":"Ayotte, Joseph D. jayotte@usgs.gov","contributorId":1802,"corporation":false,"usgs":true,"family":"Ayotte","given":"Joseph D.","email":"jayotte@usgs.gov","affiliations":[{"id":466,"text":"New England Water Science Center","active":true,"usgs":true}],"preferred":false,"id":240320,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240321,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":49823,"text":"ofr96406 - 1996 - Level II scour analysis for Bridge 46 (CHELTH00680046) on Town Highway 68, crossing the First Branch of the White River, Chelsea, Vermont","interactions":[],"lastModifiedDate":"2013-12-10T14:21:02","indexId":"ofr96406","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-406","title":"Level II scour analysis for Bridge 46 (CHELTH00680046) on Town Highway 68, crossing the First Branch of the White River, Chelsea, Vermont","docAbstract":"<p>This report provides the results of a detailed Level II analysis of scour potential at structure \nCHELTH00680046 on town highway 68 crossing the First Branch of the White River, \nChelsea, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, \nincluding a quantitative analysis of stream stability and scour (U.S. Department of \nTransportation, 1993). Results of a Level I scour investigation also are included in \nAppendix E of this report. A Level I investigation provides a qualitative geomorphic \ncharacterization of the study site. Information on the bridge, gleaned from Vermont Agency \nof Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II \nanalyses and is found in Appendix D.</p>\n<br/>\n<p>The site is in the Green Mountain section of the New England physiographic province of \ncentral Vermont in the town of Chelsea. The 58.2-mi<sup>2</sup>\n drainage area is in a predominantly \nrural and forested basin. In the vicinity of the study site, the banks have dense woody \nvegetation coverage.</p>\n<br/>\n<p>In the study area, the First Branch of the White River has a sinuous channel with a slope of \napproximately 0.0054 ft/ft, an average channel top width of 92 ft and an average channel \ndepth of 4 ft. The predominant channel bed material is gravel and cobble (D<sub>50</sub> is 52.7 mm \nor 0.173 ft). The geomorphic assessment at the time of the Level I and Level II site visit on \nNovember 16, 1994, indicated that the reach was stable.</p>\n<br/>\n<p>The town highway 68 crossing of the First Branch of the White River is a 61-ft-long, onelane covered bridge with a 52-foot clear-span (Vermont Agency of Transportation, written \ncommun., August 26, 1994). The bridge is supported by vertical, stone abutments with a \nconcrete wingwall on the downstream right. The left abutment is laid-up stone supported by \nconcrete at the upstream and downstream ends of the laid-up stone abutment. The channel \nis skewed approximately 40 degrees to the opening while the opening-skew-to-roadway is \n15 degrees.</p>\n<br/>\n<p>A scour hole 1.5 ft deeper than the mean thalweg depth was observed under the bridge \nduring the Level I assessment. The scour protection measures in place at the site were type-\n2 stone fill (less than 36 inches diameter) at the road approach embankments except the \ndownstream left embankment which had no protection. The upstream right road \nembankment, impacted by the channel bend, has an extensive covering of stone fill for \nerosion protection. Type-3 stone fill (less than 48 inches diameter) was noted along the \nright abutment. Additional details describing conditions at the site are included in the Level \nII Summary and Appendices\nD and E.</p>\n<br/>\n<p>Scour depths and rock rip-rap sizes were computed using the general guidelines described \nin 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.</p>\n<br/>\n<p>Contraction scour for all modelled flows ranged from 0.9 to 2.6 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 14.3 to \n24.0 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution. The left abutment sits atop a bedrock outcrop. The \nresults of the calculated scour depths will be limited by the bedrock.</p>\n<br/>\n<p>It 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.</p>","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96406","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., and Song, D.L., 1996, Level II scour analysis for Bridge 46 (CHELTH00680046) on Town Highway 68, crossing the First Branch of the White River, Chelsea, Vermont: U.S. Geological Survey Open-File Report 96-406, iv, 50 p., https://doi.org/10.3133/ofr96406.","productDescription":"iv, 50 p.","numberOfPages":"55","costCenters":[],"links":[{"id":178734,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96406.PNG"},{"id":279343,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0406/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Chelsea","otherGeospatial":"First Branch Of The White River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.5,43.875 ], [ -72.5,44.0 ], [ -72.375,44.0 ], [ -72.375,43.875 ], [ -72.5,43.875 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a60c8","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240322,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Song, Donald L.","contributorId":107335,"corporation":false,"usgs":true,"family":"Song","given":"Donald","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240323,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":49824,"text":"ofr96407 - 1996 - Level II scour analysis for Bridge 49 (BRIDTH00530049) on Town Highway 53, crossing North Branch Ottauquechee River, Bridgewater, Vermont","interactions":[],"lastModifiedDate":"2013-12-10T14:19:09","indexId":"ofr96407","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-407","title":"Level II scour analysis for Bridge 49 (BRIDTH00530049) on Town Highway 53, crossing North Branch Ottauquechee River, Bridgewater, Vermont","docAbstract":"<p>This report provides the results of a detailed Level II analysis of scour potential at structure \nBRIDTH00530049 on town highway 53 crossing the North Branch of the Ottauquechee \nRiver, Bridgewater, Vermont (figures 1–8). A Level II study is a basic engineering analysis \nof the site, including a quantitative analysis of stream stability and scour (U.S. Department \nof Transportation, 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 available from VTAOT files \nwas compiled prior to conducting Level I and Level II analyses and can be found in \nAppendix D.</p>\n<br/>\n<p>The site is in the Green Mountain physiographic province of central Vermont in the town of \nBridgewater. The 26.6-mi<sup>2</sup>\n drainage area is in a predominantly rural and forested basin. In \nthe vicinity of the study site, the immediate banks have woody vegetation coverage with \ngrass on the overbanks.</p>\n<br/>\n<p>In the study area, the North Branch Ottauquechee River has a sinuous channel with a slope \nof approximately 0.0075 ft/ft, an average channel top width of 66 ft and an average channel \ndepth of 6 ft. The predominant channel bed material is cobble and gravel (D<sub>50</sub> is 68.4 mm or \n0.224 ft). The geomorphic assessment at the time of the Level I and Level II site visit on \nOctober 27, 1994, indicated that the reach was stable.</p>\n<br/>\n<p>The town highway 53 crossing of the North Branch of the Ottauquechee Riveris a 51-ftlong, one-lane bridge consisting of one 49-foot steel-beam span (Vermont Agency of \nTransportation, written communication, August 25, 1994). The bridge is supported by \nvertical, concrete abutments with wingwalls. The channel is not skewed to the opening and \nthe opening-skew-to-roadway is zero degrees. </p>\n<br/>\n<p>The scour protection measures in place at the site are type-1 stone fill (less than 12 inches \ndiameter) along the upstream left wingwall and type-2 stone fill (less than 36 inches \ndiameter) along the upstream right wingwall. Additional details describing conditions at \nthe site are included in the Level II Summary and Appendices D and E.</p>\n<br/>\n<p>Scour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1993).\nTotal scour at a highway crossing is comprised of three components: 1) long-term \naggradation or degradation; 2) contraction scour (due to reduction in flow area caused by a \nbridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total \nscour is the sum of the three components. Equations are available to compute scour depths \nfor contraction and local scour and a summary of the results follows.</p>\n<br/>\n<p>Contraction scour for all modelled flows was 0 feet. Abutment scour ranged from 2.3 to \n12.0 feet and the worst-case abutment scour also occurred at the 500-year discharge. \nAdditional information on scour depths and depths to armoring are included in the section \ntitled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, \nare presented in tables 1 and 2. A cross-section of the scour computed at the bridge is \npresented in figure 8. Scour depths were calculated assuming an infinite depth of erosive \nmaterial and a homogeneous particle-size distribution.</p>\n<br/>\n<p>It is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1993, 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.</p>","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96407","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Ivanoff, M.A., and Olson, S.A., 1996, Level II scour analysis for Bridge 49 (BRIDTH00530049) on Town Highway 53, crossing North Branch Ottauquechee River, Bridgewater, Vermont: U.S. Geological Survey Open-File Report 96-407, iv, 30 p., https://doi.org/10.3133/ofr96407.","productDescription":"iv, 30 p.","numberOfPages":"35","costCenters":[],"links":[{"id":178735,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96407.PNG"},{"id":279341,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0407/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Bridgewater","otherGeospatial":"North Branch Ottauquechee 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":"4f4e4b17e4b07f02db6a5fa6","contributors":{"authors":[{"text":"Ivanoff, Michael A.","contributorId":27105,"corporation":false,"usgs":true,"family":"Ivanoff","given":"Michael","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":240325,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"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":240324,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":49826,"text":"ofr96409 - 1996 - Level II scour analysis for Bridge 32 (BRNATH00470032) on Town Highway 47, crossing Locust Creek, Barnard, Vermont","interactions":[{"subject":{"id":49826,"text":"ofr96409 - 1996 - Level II scour analysis for Bridge 32 (BRNATH00470032) on Town Highway 47, crossing Locust Creek, Barnard, Vermont","indexId":"ofr96409","publicationYear":"1996","noYear":false,"title":"Level II scour analysis for Bridge 32 (BRNATH00470032) on Town Highway 47, crossing Locust Creek, Barnard, Vermont"},"predicate":"SUPERSEDED_BY","object":{"id":50492,"text":"ofr2002150 - 2002 - Revised Protocols for Sampling Algal, Invertebrate, and Fish Communities as Part of the National Water-Quality Assessment Program","indexId":"ofr2002150","publicationYear":"2002","noYear":false,"title":"Revised Protocols for Sampling Algal, Invertebrate, and Fish Communities as Part of the National Water-Quality Assessment Program"},"id":1}],"supersededBy":{"id":50492,"text":"ofr2002150 - 2002 - Revised Protocols for Sampling Algal, Invertebrate, and Fish Communities as Part of the National Water-Quality Assessment Program","indexId":"ofr2002150","publicationYear":"2002","noYear":false,"title":"Revised Protocols for Sampling Algal, Invertebrate, and Fish Communities as Part of the National Water-Quality Assessment Program"},"lastModifiedDate":"2013-12-10T13:49:00","indexId":"ofr96409","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-409","title":"Level II scour analysis for Bridge 32 (BRNATH00470032) on Town Highway 47, crossing Locust Creek, Barnard, Vermont","docAbstract":"<p>This report provides the results of a detailed Level II analysis of scour potential at structure \nBRNATH00470032 on town highway 47 crossing Locust Creek, Barnard, 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.</p>\n<br/>\n<p>The site is in the Green Mountain section of the New England physiographic province of \ncentral Vermont in the town of Barnard. The 6.26-mi2\n drainage area is in a predominantly \nrural and forested basin. In the vicinity of the study site, the banks have dense woody \nvegetation coverage except for the upstream right bank, which is grass and brush covered.</p>\n<br/>\n<p>In the study area, Locust Creek has an incised, sinuous channel with a slope of \napproximately 0.029 ft/ft, an average channel top width of 44 ft., and an average channel \ndepth of 5 ft. The predominant channel bed material is gravel and cobbles (D50 is 91.7 mm \nor 0.301 ft). The geomorphic assessment at the time of the Level I and Level II site visit on \nOctober 12, 1994, indicated that the reach was stable.</p>\n<br/>\n<p>The town highway 47 crossing of Locust Creek is a 28-ft-long, one-lane bridge consisting \nof one 25-foot span concrete slab superstructure (Vermont Agency of Transportation, \nwritten commun., August 23, 1994). The bridge is supported by vertical, concrete\nabutments with concrete wingwalls. The channel is skewed approximately 10 degrees to the \nopening while the opening-skew-to-roadway is 35 degrees.</p>\n<br/>\n<p>The scour protection measures at the site were type-2 stone fill (less than 36 inches \ndiameter) on the banks upstream, the upstream wingwalls, the downstream right wingwall, \nand the downstream right bank. The downstream left wingwall and left bank are protected \nwith type-3 stone fill (less than 48 inches diameter). Additional details describing \nconditions at the site are included in the Level II Summary and Appendices D and E.</p>\n<br/>\n<p>Scour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1993).\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 these computed results \nfollow.</p>\n<br/>\n<p>Contraction scour for all modelled flows ranged from 1.4 to 2.2 feet. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 10.3 to \n15.0 feet. The worst-case abutment scour also occurred at the 500-year discharge. \nAdditional information on scour depths and depths to armoring are included in the section \ntitled “Scour Results”. Scoured-streambed elevations, based on the calculated depths, are \npresented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented \nin figure 8. Scour depths were calculated assuming an infinite depth of erosive material and \na homogeneous particle-size distribution. </p>\n<br/>\n<p>It is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1993, 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.</p>","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96409","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Adminitration","usgsCitation":"Boehmler, E.M., 1996, Level II scour analysis for Bridge 32 (BRNATH00470032) on Town Highway 47, crossing Locust Creek, Barnard, Vermont: U.S. Geological Survey Open-File Report 96-409, iv, 48 p., https://doi.org/10.3133/ofr96409.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":179258,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96409.PNG"},{"id":279339,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0409/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Barnard","otherGeospatial":"Locust Creek","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.625 ], [ -72.75,43.75 ], [ 72.625,43.75 ], [ 72.625,43.625 ], [ -72.75,43.625 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a7fe4b07f02db6486bf","contributors":{"authors":[{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240328,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
,{"id":49827,"text":"ofr96561 - 1996 - Level II scour analysis for Bridge 4  (MNTGTH00020004) on Town Highway 2, crossing Wade Brook, Montgomery, Vermont","interactions":[],"lastModifiedDate":"2013-12-10T13:45:03","indexId":"ofr96561","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-561","title":"Level II scour analysis for Bridge 4  (MNTGTH00020004) on Town Highway 2, crossing Wade Brook, Montgomery, Vermont","docAbstract":"<p>This report provides the results of a detailed Level II analysis of scour potential at structure \nMNTGTH00020004 on town highway 2 crossing Wade Brook, Montgomery, 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). A Level I study is included in Appendix E of this report. A Level I study provides \na qualitative geomorphic characterization of the study site. Information on the bridge, \ngleaned from VTAOT files, was compiled prior to conducting Level I and Level II analyses \nand can be found in Appendix D.</p>\n<br/>\n<p>The site is in the Green Mountain physiographic province of north-central Vermont in the \ntown of Montgomery. The 1.68-mi<sup>2</sup>\n drainage area is in a predominantly rural and forested\nbasin. In the vicinity of the study site, the banks have woody vegetation coverage.</p>\n<br/>\n<p>In the study area, Wade Brook has an incised, sinuous channel with a slope of \napproximately 0.0454 ft/ft, an average channel top width of 30 ft and an average channel \ndepth of 2 ft. The predominant channel bed materials are gravel and cobbles (D<sub>50</sub> is 77.7 \nmm or 0.255 ft). The geomorphic assessment at the time of the Level I and Level II site visit \non November 8, 1994, indicated that the reach was degraded. There were no scour holes \nobserved during the Level I assessment. However, general streambed lowering was evident \nas both abutments were undermined equally with no localized scour on one abutment over \nthe other. </p>\n<br/>\n<p>The town highway 2 crossing of Wade Brook is a 23-ft-long, two-lane bridge consisting of \none 20-foot concrete slab span (Vermont Agency of Transportation, written \ncommunication, August 3, 1994). The bridge is supported by vertical, concrete abutments \nwith wingwalls. The channel is skewed approximately 30 degrees to the opening while the \ncomputed opening-skew-to-roadway is 25 degrees. </p>\n<br/>\n<p>The scour protection measures at the site were type-1 stone fill (less than 12 inches \ndiameter) on the upstream right wingwall and all road approach embankments, type-2 stone \nfill (less than 36 inches diameter) on the left abutment, and a “laid-up” stone wall at the \nupstream end of the upstream left wingwall and in front of the upstream left bank. \nAdditional details describing conditions at the site are included in the Level II Summary \nand Appendices D and E.</p>\n<br/>\n<p>Scour depths and rock rip-rap sizes were computed using the general guidelines described \nin 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.</p>\n<br/>\n<p>Contraction scour for all modelled flows was 0.1 ft. The worst-case contraction scour \noccurred at the 100-year and 500-year discharges. Abutment scour ranged from 3.9 to 5.2 ft. \nThe worst-case abutment scour also occurred at the 500-year discharge. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution. </p>\n<br/>\n<p>It is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Many factors, \nincluding historical performance during flood events, the geomorphic assessment, scour \nprotection measures, and the results of the hydraulic analyses, must be considered to \nproperly assess the validity of abutment scour results. Therefore, scour depths adopted by \nVTAOT may differ from the computed values documented herein, based on the \nconsideration of additional contributing factors and experienced engineering judgement.</p>","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96561","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Boehmler, E.M., 1996, Level II scour analysis for Bridge 4  (MNTGTH00020004) on Town Highway 2, crossing Wade Brook, Montgomery, Vermont: U.S. Geological Survey Open-File Report 96-561, iv, 48 p., https://doi.org/10.3133/ofr96561.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":179259,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96561.PNG"},{"id":279338,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0561/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Montgomergy","otherGeospatial":"Wade Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.5 ], [ -72.75,43.625 ], [ -72.625,43.625 ], [ -72.625,43.5 ], [ -72.75,43.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a6220","contributors":{"authors":[{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240329,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
,{"id":49831,"text":"ofr96565 - 1996 - Level II scour analysis for Bridge 42 (HARDELMSTR0042) on Elm Street, crossing Cooper Brook, Hardwick, Vermont","interactions":[],"lastModifiedDate":"2013-12-10T13:41:46","indexId":"ofr96565","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-565","title":"Level II scour analysis for Bridge 42 (HARDELMSTR0042) on Elm Street, crossing Cooper Brook, Hardwick, Vermont","docAbstract":"<p>This report provides the results of a detailed Level II analysis of scour potential at structure HARDELMSTR0042 on Elm Street crossing Cooper Brook, Hardwick, 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.</p>\n<br/>\n<p>The site is in the New England Upland section of the New England physiographic province in north-central Vermont. The 16.6-mi2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the overbanks are primarily grass covered with some brush along the immediate channel banks except the upstream right bank and overbank which is forested and the downstream left overbank which has a lumberyard.</p>\n<br/>\n<p>In the study area, Cooper Brook has a sinuous channel with a slope of approximately 0.005 ft/ft, an average channel top width of 50 ft and an average channel depth of 6 ft. The predominant channel bed materials are sand and gravel with a median grain size (D50) of 1.25 mm (0.00409 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 24, 1995, indicated that the reach was stable.</p>\n<br/>\n<p>The Elm Street crossing of Cooper Brook is a 39-ft-long, two-lane bridge consisting of one 37-foot concrete span (Vermont Agency of Transportation, written communication, March 17, 1995). The bridge is supported by vertical, concrete abutments with wingwalls. The channel is skewed approximately 40 degrees to the opening while the opening-skew-to-roadway is 45 degrees.</p>\n<br/>\n<p>On August 17, 1995 the site was revisited to investigate the effect of the August 4-5, 1995 flood on the structure. Channel features such as scour holes and point bars were shifted by the high flow event. Details of these changes can be found in the Level I data form in Appendix E. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and G.</p>\n<br/>\n<p>Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). 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.</p>\n<br/>\n<p>Contraction scour for all modelled flows ranged from 0.0 to 3.4 ft. The worst-case contraction scour occurred at the incipient-overtopping discharge which was less than the 100-year discharge. Abutment scour ranged from 7.1 to 10.4 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.</p>\n<br/>\n<p>It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1993, p. 48). 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.</p>","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96565","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Olson, S.A., 1996, Level II scour analysis for Bridge 42 (HARDELMSTR0042) on Elm Street, crossing Cooper Brook, Hardwick, Vermont: U.S. Geological Survey Open-File Report 96-565, iv, 55 p., https://doi.org/10.3133/ofr96565.","productDescription":"iv, 55 p.","numberOfPages":"60","costCenters":[],"links":[{"id":162471,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96565.PNG"},{"id":279296,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0565/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Hardwick","otherGeospatial":"Cooper Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.5,44.375 ], [ -72.5,44.625 ], [ -72.25,44.625 ], [ -72.25,44.375 ], [ -72.5,44.375 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a5fc4","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":240335,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
,{"id":49834,"text":"ofr96568 - 1996 - Level II scour analysis for Bridge 45b (BRIDTH00040045b) on Town Highway 4, crossing an unnamed Dailey Hollow Branch Tributary, Bridgewater, Vermont","interactions":[],"lastModifiedDate":"2013-12-10T10:32:37","indexId":"ofr96568","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-568","title":"Level II scour analysis for Bridge 45b (BRIDTH00040045b) on Town Highway 4, crossing an unnamed Dailey Hollow Branch Tributary, Bridgewater, Vermont","docAbstract":"<p>This report provides the results of a detailed Level II analysis of scour potential at structure BRIDTH0004045B on town highway 4 crossing an unnamed Dailey Hollow Branch Tributary, Bridgewater, 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.</p>\n<br/>\n<p>The site is in the Green Mountain section of the New England physiographic province in central Vermont. The 2.47-mi<sup>2</sup> drainage area is in a predominantly rural and forested basin. Surface cover in the vicinity of the study site is variable. A gravel road is adjacent to the left bank with the immediate upstream left bank covered by grass and the immediate downstream left bank covered by shrubs and brush. The upstream right bank is densely forested; the downstream right overbank is covered by grass with trees and brush on the immediate channel bank.</p>\n<br/>\n<p>In the study area, this unnamed Dailey Hollow Branch Tributary has an incised channel with a slope of approximately 0.04 ft/ft, an average channel top width of 29 ft and an average channel depth of 4 ft. The predominant channel bed material is gravel with a median grain size (D<sub>50</sub>) of 47.0 mm (0.154 ft). The geomorphic assessment at the time of the Level I and Level II site visit on November 15, 1994, indicated that the reach was stable.</p>\n<br/>\n<p>The town highway 4 crossing of the unnamed Dailey Hollow Branch Tributary is a 62-ft-long, corrugated steel multi-plate arch structure. It is supported by concrete footings leaving natural stream bed exposed (Vermont Agency of Transportation, written communication, January, 1996). The road embankments are protected by stone fill, however, the size is unknown due to sand and grass covering the fill except for the upstream left embankment which has type-2 stone fill (less than 36 inches diameter). The downstream left bank is protected by type-3 stone fill (less than 48 inches diameter) extending 25 feet downstream of the culvert. The channel approach to the culvert has a mild s-curve bend with the opening skewed ten degrees to flow. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.</p>\n<br/>\n<p>Scour depths and rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and others, 1993). 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.</p>\n<br/>\n<p>Contraction scour for all modelled flows ranged from 1.1 to 1.8 ft. The worst-case contraction scour occurred at the 500-year discharge. Abutment scour ranged from 7.7 to 11.7 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution.</p>\n<br/>\n<p>It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and others, 1993, p. 48). 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.</p>","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96568","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Boehmler, E.M., 1996, Level II scour analysis for Bridge 45b (BRIDTH00040045b) on Town Highway 4, crossing an unnamed Dailey Hollow Branch Tributary, Bridgewater, Vermont: U.S. Geological Survey Open-File Report 96-568, iv, 47 p., https://doi.org/10.3133/ofr96568.","productDescription":"iv, 47 p.","numberOfPages":"52","costCenters":[],"links":[{"id":162558,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96568.PNG"},{"id":279293,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0568/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Bridgewater","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.75,43.625 ], [ -72.75,43.75 ], [ -72.625,43.75 ], [ -72.625,43.625 ], [ -72.75,43.625 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a60e8","contributors":{"authors":[{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240339,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
,{"id":49835,"text":"ofr96569 - 1996 - Level II scour analysis for Bridge 28 (HARDTH00300028) on Town Highway 30, crossing the Lamoille River, Hardwick, Vermont","interactions":[],"lastModifiedDate":"2013-12-10T10:22:12","indexId":"ofr96569","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-569","title":"Level II scour analysis for Bridge 28 (HARDTH00300028) on Town Highway 30, crossing the Lamoille River, Hardwick, Vermont","docAbstract":"<p>This report provides the results of a detailed Level II analysis of scour potential at structure HARDTH00300028 on town highway 30 crossing the Lamoille River, Hardwick, 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.</p>\n<br/>\n<p>The site is in the New England Upland section of the New England physiographic province in north-central Vermont. The 63.7-mi<up>2</sup> drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover upstream and on the downstream right is primarily pasture with some row crops. Trees line the immediate channel banks. The left bank downstream surface cover is primarily brush.</p>\n<br/>\n<p>In the study area, the Lamoille River has an incised, sinuous channel with a slope of approximately 0.002 ft/ft, an average channel top width of 76 ft and an average bank height of 6 ft. The predominant channel bed materials are gravel and cobble with a median grain size (D<sub>50</sub>) of 46.6 mm (0.153 ft). The geomorphic assessment at the time of the Level I and Level II site visit on July 25, 1995, indicated that the reach was laterally unstable. The site was revisited on August 21, 1995, after the August 5-6, 1995 flood on the Lamoille River. Findings from this follow-up visit are presented in Appendix G.</p>\n<br/>\n<p>The town highway 30 crossing of the Lamoille River is a 54-ft-long, one-lane bridge consisting of one 52-foot steel-beam span (Vermont Agency of Transportation, written communication, April 3, 1995). The bridge is supported by vertical, stone abutments with wingwalls. Scour, about one foot below the mean thalweg, exists along the right abutment and right upstream wingwall. Sheet piling has been driven around the right abutment and wingwalls and filled with concrete. The channel is skewed approximately 5 degrees to the opening while the opening-skew-to-roadway is 0 degrees. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.</p>\n<br/>\n<p>Scour depths and 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.</p>\n<br/>\n<p>Contraction scour for all modelled flows ranged from 1.9 to 2.5 ft. The worst-case contraction scour occurred at the 100-year discharge. Abutment scour ranged from 11.2 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.</p>\n<br/>\n<p>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.</p>","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96569","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Olson, S.A., and Degnan, J.R., 1996, Level II scour analysis for Bridge 28 (HARDTH00300028) on Town Highway 30, crossing the Lamoille River, Hardwick, Vermont: U.S. Geological Survey Open-File Report 96-569, iv, 64 p., https://doi.org/10.3133/ofr96569.","productDescription":"iv, 64 p.","numberOfPages":"69","costCenters":[],"links":[{"id":162559,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96569.PNG"},{"id":279292,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0569/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Hardwick","otherGeospatial":"Lamoille River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.375,44.5 ], [ -72.375,44.625 ], [ -72.25,44.625 ], [ -72.25,44.5 ], [ -72.375,44.5 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b19e4b07f02db6a7f87","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":240341,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Degnan, James R. 0000-0002-5665-9010 jrdegnan@usgs.gov","orcid":"https://orcid.org/0000-0002-5665-9010","contributorId":498,"corporation":false,"usgs":true,"family":"Degnan","given":"James","email":"jrdegnan@usgs.gov","middleInitial":"R.","affiliations":[{"id":405,"text":"NH/VT office of New England Water Science Center","active":true,"usgs":true},{"id":466,"text":"New England Water Science Center","active":true,"usgs":true}],"preferred":true,"id":240340,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":49836,"text":"ofr96570 - 1996 - Level II scour analysis for Bridge 10 (HANCTH00010010) on Town Highway 1, crossing the White River, Hancock, Vermont","interactions":[],"lastModifiedDate":"2013-12-10T10:25:52","indexId":"ofr96570","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-570","title":"Level II scour analysis for Bridge 10 (HANCTH00010010) on Town Highway 1, crossing the White River, Hancock, Vermont","docAbstract":"<p>This report provides the results of a detailed Level II analysis of scour potential at structure HANCTH00010010 on town highway 1 crossing the White River, Hancock, 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.</p>\n<br/>\n<p>The site is in the Green Mountain section of the New England physiographic province of central Vermont. The 59.8-mi<sup>2</sup> drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is primarily grass with trees and brush on the immediate channel banks.</p>\n<br/>\n<p>In the study area, the White River has a sinuous channel with a slope of approximately 0.005 ft/ft, an average channel top width of 104 ft and an average channel depth of 6 ft. The predominant channel bed materials are gravel and cobble with a median grain size (D50) of 98.9 mm (0.325 ft). The geomorphic assessment at the time of the Level I and Level II site visit on November 15, 1994, indicated that the reach was stable.</p>\n<br/>\n<p>The town highway 1 crossing of the White River is a 91-ft-long, two-lane bridge consisting of one 89-foot steel-beam span (Vermont Agency of Transportation, written communication, August 26, 1994). 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 0 degrees. Additional details describing conditions at the site are included in the Level II Summary and Appendices D and E.</p>\n<br/>\n<p>Scour depths and 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.</p>\n<br/>\n<p>Contraction scour for all modelled flows was 0.0 feet. Abutment scour ranged from 13.1 to 17.1 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.</p>\n<br/>\n<p>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.</p>","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Pembroke, NH","doi":"10.3133/ofr96570","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Olson, S.A., and Ivanoff, M.A., 1996, Level II scour analysis for Bridge 10 (HANCTH00010010) on Town Highway 1, crossing the White River, Hancock, Vermont: U.S. Geological Survey Open-File Report 96-570, iv, 51 p., https://doi.org/10.3133/ofr96570.","productDescription":"iv, 51 p.","numberOfPages":"56","costCenters":[],"links":[{"id":162560,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96570.PNG"},{"id":279291,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0570/report.pdf"}],"scale":"24000","country":"United States","state":"Vermont","city":"Hancock","otherGeospatial":"White River","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.875,43.875 ], [ -72.875,44.0 ], [ -72.75,44.0 ], [ -72.75,43.875 ], [ -72.875,43.875 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1ae4b07f02db6a8456","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":240342,"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":240343,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":49837,"text":"ofr96571 - 1996 - Level II scour analysis for Bridge 5 (IRASTH00010005) on Town Highway 1, crossing Lords Creek, Irasburg, Vermont","interactions":[],"lastModifiedDate":"2013-12-05T16:19:17","indexId":"ofr96571","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-571","title":"Level II scour analysis for Bridge 5 (IRASTH00010005) on Town Highway 1, crossing Lords Creek, Irasburg, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nIRASTH00010005 on town highway 1 crossing Lords Creek, Irasburg, Vermont (figures 1–\n8). A Level II study is a basic engineering analysis of the site, including a quantitative \nanalysis of stream stability and scour (U.S. Department of Transportation, 1993). Results of \na Level I scour investigation also are included in Appendix E of this report. A Level I \ninvestigation provides a qualitative geomorphic characterization of the study site. \nInformation on the bridge, gleaned from VTAOT files, was compiled prior to conducting \nLevel I and Level II analyses and can be found in Appendix D.\nThe site is in the New England Upland section of the New England physiographic province \nof north-central Vermont in the town of Irasburg. The 15.1-mi<sup>2</sup>\n drainage area is in a \npredominantly rural and forested basin with some pasture land mainly along the valley \nbottom. In the vicinity of the study site, the bank vegetation coverage is pasture grasses.\nIn the study area, Lords Creek has a meandering channel with a slope of approximately \n0.0026 ft/ft, an average channel top width of 32 ft and an average channel depth of 3 ft. The \nchannel bed material ranged from gravel (D50 is 46.6 mm or 0.153 ft) to silt/clay material \n(D<sub>50</sub> of 1.006 mm or 0.0033 ft). The geomorphic assessment at the time of the Level I and \nLevel II site visit on October 5 and 6, 1994, indicated that the reach was laterally unstable.\nThe town highway 1 crossing of Lords Creek is a 65-ft-long, two-lane bridge consisting of \none 61-foot, steel-beam span (Vermont Agency of Transportation, written communication, \nAugust 2, 1994). The bridge is supported by vertical, concrete abutments on wooden piles \ndriven to bedrock with no wingwalls. Each abutment wall has a spill-through slope \nprotected with type-2 stone fill (less than 36 inches diameter). The channel is skewed \napproximately 25 degrees to the opening while the opening-skew-to-roadway is 15 degrees. \nAdditional details describing conditions at the site are included in the Level II Summary \nand Appendices D and E.\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1995).\nTotal scour at a highway crossing is comprised of three components: 1) long-term \nstreambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction \nin flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and \nabutments). Total scour is the sum of the three components. Equations are available to \ncompute depths for contraction and local scour and a summary of the results of these \ncomputations follows.\nContraction scour for all modelled flows ranged from 2.4 to 4.6 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 7.2 to \n9.8 ft. The worst-case abutment scour also occurred at the 500-year discharge. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution. \nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.","language":"English","publisher":"U.S. Geological Survey","doi":"10.3133/ofr96571","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Boehmler, E.M., and Song, D.L., 1996, Level II scour analysis for Bridge 5 (IRASTH00010005) on Town Highway 1, crossing Lords Creek, Irasburg, Vermont: U.S. Geological Survey Open-File Report 96-571, iv, 49 p., https://doi.org/10.3133/ofr96571.","productDescription":"iv, 49 p.","numberOfPages":"54","costCenters":[],"links":[{"id":162561,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96571.PNG"},{"id":279290,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0571/report.pdf"}],"country":"United States","state":"Vermot","city":"Irasburg","otherGeospatial":"Lords Creek","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.374482,44.752937 ], [ -72.374482,44.875157 ], [ -72.195393,44.875157 ], [ -72.195393,44.752937 ], [ -72.374482,44.752937 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b17e4b07f02db6a5f94","contributors":{"authors":[{"text":"Boehmler, Erick M.","contributorId":96303,"corporation":false,"usgs":true,"family":"Boehmler","given":"Erick","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":240344,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Song, Donald L.","contributorId":107335,"corporation":false,"usgs":true,"family":"Song","given":"Donald","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":240345,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":49838,"text":"ofr96572 - 1996 - Level II scour analysis for Bridge 99 (LUDLVT01000099) on State Highway 99, crossing Branch Brook, Ludlow, Vermont","interactions":[],"lastModifiedDate":"2013-12-05T16:13:32","indexId":"ofr96572","displayToPublicDate":"1994-01-01T00:00:00","publicationYear":"1996","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":"96-572","title":"Level II scour analysis for Bridge 99 (LUDLVT01000099) on State Highway 99, crossing Branch Brook, Ludlow, Vermont","docAbstract":"This report provides the results of a detailed Level II analysis of scour potential at structure \nLUDLVT01000099 on State Highway 100 crossing Branch Brook, Ludlow, Vermont \n(figures 1–8). A Level II study is a basic engineering analysis of the site, including a \nquantitative analysis of stream stability and scour (U.S. Department of Transportation, \n1993). Results of a Level I scour investigation also are included in Appendix E of this \nreport. A Level I investigation provides a qualitative geomorphic characterization of the \nstudy site. Information on the bridge, gleaned from Vermont Agency of Transportation \n(VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is \nfound in Appendix D.\nThe site is in the Green Mountain section of the New England physiographic province in \ncentral Vermont. The 15.7-mi<sup>2</sup>\n drainage area is in a predominantly rural and forested basin. \nIn the vicinity of the study site, the channel banks are densely covered by trees and brush. \nThe overbanks are primarily covered by field grasses.\nIn the study area, Branch Brook has an incised, straight channel with a slope of \napproximately 0.003 ft/ft, an average channel top width of 73 ft and an average channel \ndepth of 5 ft. The predominant channel bed materials are cobble and gravel with a median \ngrain size (D<sub>50</sub>) of 60.5 mm (0.198 ft). The geomorphic assessment at the time of the Level \nI and Level II site visit on October 13, 1995, indicated that the reach was stable.\nThe State Highway 100 crossing of Branch Brook is a 84-ft-long, two-lane bridge \nconsisting of one 82-foot steel-beam span (Vermont Agency of Transportation, written \ncommunication, March 13, 1995). The bridge is supported by vertical, concrete abutments. \nThe abutments are set back from the channel edge and have a spill-through slope consisting \nof type-4 stone fill (median size less than 60 inches in diameter). The channel skew and the \nopening-skew-to-roadway is zero degrees. Additional details describing conditions at the \nsite are included in the Level II Summary and Appendices D and E.\nScour depths and rock rip-rap sizes were computed using the general guidelines described \nin Hydraulic Engineering Circular 18 (Richardson and others, 1995). Total scour at a \nhighway crossing is comprised of three components: 1) long-term streambed degradation; \n2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) \nand; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is \nthe sum of the three components. Equations are available to compute depths for contraction \nand local scour and a summary of the results of these computations follows.\nContraction scour for all modelled flows ranged from 0.0 to 1.5 ft. The worst-case \ncontraction scour occurred at the 500-year discharge. Abutment scour ranged from 1.0 to \n7.4 ft. The worst-case abutment scour occurred at the 500-year discharge. Additional \ninformation on scour depths and depths to armoring are included in the section titled “Scour \nResults”. Scoured-streambed elevations, based on the calculated scour depths, are presented \nin tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure \n8. Scour depths were calculated assuming an infinite depth of erosive material and a \nhomogeneous particle-size distribution. \nIt is generally accepted that the Froehlich equation (abutment scour) gives “excessively \nconservative estimates of scour depths” (Richardson and others, 1995, p. 47). Usually, \ncomputed scour depths are evaluated in combination with other information including (but \nnot limited to) historical performance during flood events, the geomorphic stability \nassessment, existing scour protection measures, and the results of the hydraulic analyses. \nTherefore, scour depths adopted by VTAOT may differ from the computed values \ndocumented herein.","language":"English","publisher":"U.S. Geological Survey","doi":"10.3133/ofr96572","collaboration":"Prepared in cooperation with Vermont Agency of Transportation and Federal Highway Administration","usgsCitation":"Olson, S.A., 1996, Level II scour analysis for Bridge 99 (LUDLVT01000099) on State Highway 99, crossing Branch Brook, Ludlow, Vermont: U.S. Geological Survey Open-File Report 96-572, iv, 48 p., https://doi.org/10.3133/ofr96572.","productDescription":"iv, 48 p.","numberOfPages":"53","costCenters":[],"links":[{"id":162562,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/ofr96572.PNG"},{"id":279289,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/1996/0572/report.pdf"}],"country":"United States","state":"Vermont","city":"Ludlow","otherGeospatial":"Branch Brook","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -72.759799,43.32211 ], [ -72.759799,43.468717 ], [ -72.661104,43.468717 ], [ -72.661104,43.32211 ], [ -72.759799,43.32211 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b16e4b07f02db6a55a1","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":240346,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
]}