{ "bbox":null, "type":"Feature", "geometry":{ "bbox":null, "type":"Point", "coordinates":[ -96.52556, 30.32222 ] }, "properties":{ "provider":"SWF", "code":"SOMT2", "slug":"somt2", "elevation":0.0, "horizontal_datum":"", "vertical_datum":"NGVD29", "state":"TX", "kind":"PROJECT", "nearest_city":"Somerville, TX", "public_name":"Somerville Lake", "location_code":187048, "nsid":null, "aliases":{ "NID Dam Name":"SOMERVILLE LAKE", "NIDID":"TX00013" }, "timeseries":[ { "tsid":"SOMT2.Stor.Inst.1Hour.0.Decodes-Rev", "label":"Conservation Storage", "base_parameter":"Stor", "parameter":"Stor", "unit":"ac-ft", "unit_long_name":"Acre-feet", "latest_time":"2026-04-14T22:00:00Z", "latest_value":111640.61, "delta24h":null, "sort_order":13, "results":null }, { "tsid":"SOMT2.Elev.Inst.1Hour.0.Decodes-Rev", "label":"Elevation", "base_parameter":"Elev", "parameter":"Elev", "unit":"ft", "unit_long_name":"Feet", "latest_time":"2026-04-14T22:00:00Z", "latest_value":234.31, "delta24h":null, "sort_order":1, 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"units_long_name":"Acre-feet" } ], "id":550003, "associatedStructuresCount":0, "conditionAssessDate":null, "conditionAssessDetail":null, "conditionAssessId":6, "damHeight":80, "damLength":20210, "distance":null, "drainageArea":1012, "eapId":1, "dsacAssignedDate":"2019-03-29T12:00:00.000Z", "eapMeetsGuidelinesId":1, "emergencyContactsUpdated":"2024-09-27T12:00:00.000Z", "eapLastRevDate":"2020-09-18T12:00:00.000Z", "enforcementAuthorityId":0, "federalId":"TX00013", "oldFederalId":"TX00013", "hazardId":4, "hydraulicHeight":75, "inspectionAuthorityId":0, "inspectionDate":"2023-05-16T12:00:00.000Z", "inspectionFrequency":5, "jurisdictionAuthorityId":0, "latitude":30.320401529, "lengthOfLocks":0, "secondaryLengthOfLocks":null, "longitude":-96.524091374, "maxDischarge":348081, "maxStorage":1042000, "nidHeight":80, "nidStorage":1042000, "normalStorage":226000, "numberOfLocks":0, "operationalStatusDate":"2019-03-29T12:00:00.000Z", "operationalStatusId":2, "originalDesignerName":null, "otherStructureId":null, "permittingAuthorityId":0, "politicalPartyId":null, "privateDamId":null, "projectDescription":"The U.S. Army Corps of Engineers (USACE) completed construction of Somerville Dam in December 1967 in accordance with the Flood Control Act approved 3 September 1954 (Public Law 780, 83rd Congress, 2nd Session), and in accordance with the recommendation of the Chief of Engineers contained in House Document No. 535 (81st Congress, 2nd Session) \u201cReport of Survey of Brazos River and Tributaries, Texas, Oyster Creek, Texas and Jones Creek, Texas\u201d. Somerville Dam is located immediately upstream of the town of Somerville, Texas at river mile 20 on Yegua Creek and reduces the risk of flooding to downstream communities by holding back waters during heavy rain events until they can be released without damage to lives, property or the environment. Somerville Lake is operated as part of the Brazos River Basin System, providing flood protection along the Brazos River and its tributaries. The sponsoring agency is the Brazos River Authority (BRA). The dam consists of an earthen embankment and dike that holds water in the reservoir, rising stem sluice gates that are operated to release water in a regulated manner during and after flood events, and an uncontrolled ogee weir spillway which holds water to 22\u2010feet below the top of the dam to allow water to flow out when water levels within the reservoir become high. The dam embankment is made up of soil and rock and is approximately 80 feet high (about 8 stories) at a crest elevation of 280.1 feet (NAVD88 vertical datum control). The earthen dike, located west of the spillway, is 20 feet tall and 4,715 feet in length. The reservoir is kept at or below the conservation pool elevation of 238.1 feet NAVD88 for most of the year. When heavy rains occur, surface water runoff is stored in the reservoir and releases are made in accordance with the water control manual. Somerville Dam is designed to reduce the peak flooding levels downstream without risking the structural integrity of the dam. Although flood risk management is the project\u2019s primary focus, Somerville Dam is also utilized for water supply, recreation, and environmental benefits. These benefits significantly improve the quality of life in the area.", "riskCharSummary":"Even though Somerville Dam reduces the risk of flooding to the downstream communities, the dam does not eliminate the risk of flooding. USACE Fort Worth District completed a risk assessment for Somerville Dam in April 2018 that characterizes the risk associated with the project as moderate. This classification is primarily based upon events involving the possibility of; (1) concentrated leak erosion of the embankment core material into the downstream embankment at the Main Dam; (2) concentrated leak erosion along the left abutment embankment contact; and/or (3) embankment material eroding into fractures and openings in the foundation rock near an inactive fault. Also, the dam overtops during extreme flood events. Due to lack of as\u2010built construction documentation, there is significant uncertainty regarding the physical characteristics of the dam as related to these types of failure mechanisms. Although Somerville Dam has historically performed well, extreme rainfall and hurricane events may cause areas downstream to be flooded. Even when the dam operates in accordance with the water control manual, downstream flooding is possible during very large rain events, necessitating large quantities of water to be released through the dam gates and uncontrolled spillway. In the remote event of a dam breach, the largest impacts would be to the city of Somerville, TX, located immediately downstream of the dam. In any of these unlikely scenarios, downstream flooding in Somerville, TX would occur within 30 minutes of breach and could reach 16.7 feet above the top of bank, destroying buildings and critical infrastructure. Although local communities have well\u2010practiced emergency action plans and local emergency managers meet regularly with USACE to discuss emergency response to flood events, including the unlikely potential for dam failure, breach of the dam would result in significant loss of life and severe economic damages.", "riskManagementMeasures":"To lower the risks associated with the dam, inspections and monitoring are performed regularly to ensure the health and safety of the dam. Surveillance and inspections are increased as the lake elevation rises. Routine maintenance and dam safety monitoring are performed to ensure the dam is functioning as designed. Somerville Dam is well maintained with an instrumentation and monitoring system, allowing USACE staff the ability to evaluate the dam for changing conditions. In 2018, the Vicksburg District cleaned the relief well system to maintain its efficiency and meet current guidelines for frequency of cleaning relief wells. The USACE is currently assessing the necessity for cleaning the relief well system on this recurring 5\u2010year interval based on modern\u2010day seepage analyses. In addition, USACE continues to identify and implement interim risk reduction measures such as stockpiling materials for emergency flood fighting; monitoring structural movement and settlement through drone topographic surveys; cleaning, inspecting, and maintaining project instrumentation; dewatering and inspecting the outlet works and spillway stilling basins; evaluating the need to install new instrumentation; repairing the spillway drainage system; inspecting the conduit; and repairing/replacing outlet works gates. USACE Fort Worth District works closely with local emergency managers to encourage and support the development and update of local evacuation plans to maximize time for evacuation and designating evacuation routes; regularly update the Somerville Dam Emergency Action Plan; conduct emergency exercises with state and local response teams, and annually communicate risks associated with Somerville Dam with stakeholders and Emergency Managers.", "riverName":"YEGUA CREEK", "separateStructuresCount":0, "sourceAgency":"US Army Corps of Engineers", "spillwayTypeId":3, "spillwayWidth":1250, "stateFedId":"TX00013", "stateRegulatoryAgency":null, "stateRegulatedId":0, "structuralHeight":80, "submitDate":"2023-10-26T00:00:00.000Z", "surfaceArea":6430, "volume":7434000, "widthOfLocks":0, "secondaryWidthOfLocks":null, "yearCompleted":1967, "congDist":"Congressional District 10, Texas", "city":"SOMERVILLE", "county":"Washington", "aiannh":null, "websiteUrl":"https://www.swf-wc.usace.army.mil/somerville/", "coreTypeIds":"3", "damTypeIds":"8", "fedConstructionIds":"1", "fedDesignIds":"1", "fedFundingIds":"1", "fedInspectionIds":"1", "fedOperationIds":"1", "fedOtherIds":"1", "fedOwnerIds":"1", "fedRegulatoryIds":"1", "formerNames":null, "foundationTypeIds":"1;3", "nonFederalDamOnFederalId":0, "designerNames":"CESWF", "otherNames":null, "ownerNames":"USACE - Fort Worth District", "ownerTypeIds":"3", "primaryDamTypeId":8, "primaryOwnerTypeId":3, "primaryPurposeId":9, "purposeIds":"9;4;5;8", "dsacId":3, "femaRegion":"6", "lastEapExcerDate":"2025-06-26T12:00:00.000Z", "dataUpdated":"2025-07-02T12:00:00.000Z", "usaceDistrict":"Fort Worth District", "noConsequencesId":0, "secretaryAgricultureBuiltId":null, "nrcsWatershedAuthorizationId":null, "isAssociatedStructureId":"No", "fedRegulatedId":"Yes", "inundationNidAddedId":1, "damStatusId":2, "huc06":"120701", "doi_region":"ART", "doi_region_name":"Arkansas-Rio Grande-Texas Gulf", "doi_region_number":6, "thirtyYearAverage":199.7666, "tenthPercentile":149.8024, "ninetiethPercentile":232.1597 }, "id":187048, "links":[ { "type":"application/json", "rel":"root", "title":"The landing page of this server as JSON", "href":"https://api.wwdh.internetofwater.app?f=json" }, { "type":"text/html", "rel":"root", "title":"The landing page of this server as HTML", "href":"https://api.wwdh.internetofwater.app?f=html" }, { "rel":"self", "type":"application/geo+json", "title":"This document as JSON", "href":"https://api.wwdh.internetofwater.app/collections/usace-edr/items/187048?f=json" }, { "rel":"alternate", "type":"application/ld+json", "title":"This document as RDF (JSON-LD)", "href":"https://api.wwdh.internetofwater.app/collections/usace-edr/items/187048?f=jsonld" }, { "rel":"alternate", "type":"text/html", "title":"This document as HTML", "href":"https://api.wwdh.internetofwater.app/collections/usace-edr/items/187048?f=html" }, { "rel":"collection", "type":"application/json", "title":"USACE Access2Water API", "href":"https://api.wwdh.internetofwater.app/collections/usace-edr" } ] }