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"label":"Top of Inactive", "parameter":"Elev", "base_parameter":"Elev", "tsid":"STIT2.Elev.Inst.0.Top of Inactive", "latest_value":515, "units":"ft", "units_long_name":"Feet" }, { "slug":"stor.bottom of inactive", "label":"Bottom of Inactive", "parameter":"Stor", "base_parameter":"Stor", "tsid":"STIT2.Stor.Inst.0.Bottom of Inactive", "latest_value":0, "units":"ac-ft", "units_long_name":"Acre-feet" }, { "slug":"stor.design capacity", "label":"Design Capacity", "parameter":"Stor", "base_parameter":"Stor", "tsid":"STIT2.Stor.Inst.0.Design Capacity", "latest_value":1002168, "units":"ac-ft", "units_long_name":"Acre-feet" }, { "slug":"stor.spillway crest", "label":"Spillway Crest", "parameter":"Stor", "base_parameter":"Stor", "tsid":"STIT2.Stor.Inst.0.Spillway Crest", "latest_value":622489, "units":"ac-ft", "units_long_name":"Acre-feet" }, { "slug":"stor.streambed", "label":"Streambed", "parameter":"Stor", "base_parameter":"Stor", "tsid":"STIT2.Stor.Inst.0.Streambed", "latest_value":0, "units":"ac-ft", "units_long_name":"Acre-feet" }, { "slug":"stor.top of conservation", "label":"Top of Conservation", "parameter":"Stor", "base_parameter":"Stor", "tsid":"STIT2.Stor.Inst.0.Top of Conservation", "latest_value":229881, "units":"ac-ft", "units_long_name":"Acre-feet" }, { "slug":"stor.top of flood", "label":"Top of Flood", "parameter":"Stor", "base_parameter":"Stor", "tsid":"STIT2.Stor.Inst.0.Top of Flood", "latest_value":624581, "units":"ac-ft", "units_long_name":"Acre-feet" }, { "slug":"stor.top of inactive", "label":"Top of Inactive", "parameter":"Stor", "base_parameter":"Stor", "tsid":"STIT2.Stor.Inst.0.Top of Inactive", "latest_value":86, "units":"ac-ft", "units_long_name":"Acre-feet" } ], "id":550004, "associatedStructuresCount":0, "conditionAssessDate":null, "conditionAssessDetail":null, "conditionAssessId":6, "damHeight":195, "damLength":9720, "distance":null, "drainageArea":1319, "eapId":1, "dsacAssignedDate":"2019-09-21T12:00:00.000Z", "eapMeetsGuidelinesId":1, "emergencyContactsUpdated":"2024-09-27T12:00:00.000Z", "eapLastRevDate":"2022-08-09T12:00:00.000Z", "enforcementAuthorityId":0, "federalId":"TX00014", "oldFederalId":"TX00014", "hazardId":4, "hydraulicHeight":195, "inspectionAuthorityId":0, "inspectionDate":"2021-05-13T12:00:00.000Z", "inspectionFrequency":5, "jurisdictionAuthorityId":0, "latitude":31.0224470520001, "lengthOfLocks":0, "secondaryLengthOfLocks":null, "longitude":-97.531105918, "maxDischarge":781483, "maxStorage":1013800, "nidHeight":200, "nidStorage":1013800, "normalStorage":235700, "numberOfLocks":0, "operationalStatusDate":"2019-09-21T12:00:00.000Z", "operationalStatusId":1, "originalDesignerName":null, "otherStructureId":null, "permittingAuthorityId":0, "politicalPartyId":null, "privateDamId":null, "projectDescription":"The U.S. Army Corps of Engineers (USACE) completed construction of Stillhouse Hollow Dam in 1968 in accordance with the Flood Control Act approved 3 September 1954 (Public Law 780, 83rd Congress, Second Session) and substantially in accordance with the recommendations of the Chief of Engineers contain 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 Stillhouse Hollow Dam, formerly known as Lampasas Dam, was built on the Lampasas River to reduce the risk of flooding to the downstream Texas cities of Belton, Little River/Academy, and adjacent towns and counties by holding back waters during heavy rain events until they can be released without damage to lives, property or the environment. Stillhouse Hollow Dam is located 5 miles southwest of the City of Belton in Bell County, Texas. The dam consists of an earthen embankment and dike that holds water in the reservoir, hydraulic slide gates that are operated to release water in a regulated manner during and after flood events, and an uncontrolled broadcrested weir spillway which holds water to 32\u2010feet below the top of the dam to allow water to flow out when water levels within the reservoir become high. The dam is made up of soil and rock and is approximately 200 feet high (approximately 20 stories) at a crest elevation of 698.24 feet (NAVD88 vertical datum control). The embankment is approximately 8,070 feet long, not including the spillway. The earthen dike, located south of the spillway, is 6,004 feet long and armored with riprap on the upstream slope. The reservoir is kept at or below the conservation pool elevation of 622.24 feet NAVD88 for most of the year. When heavy rains occur, surface water runoff is stored in the reservoir and released in accordance with the water control manual. Although flood risk management is the project\u2019s primary focus, the dam also provides water conservation, water supply, and unique recreation opportunities. These benefits significantly improve the quality of life in the surrounding communities.", "riskCharSummary":"Even though Stillhouse Hollow Dam reduces the risk of flooding to the downstream communities, the dam does not eliminate the risk of flooding. USACE Fort Worth District performed a Semi\u2010Quantitative Risk Assessment (SQRA) in January 2014 and completed a 2019 Phase 2 Issue Evaluation Study (IES). The Phase II IES was conducted to better define the risk characterization of the project and reduce uncertainties. Field investigations were conducted, including mapping of three faults, mapping of bedrock, and completing material sampling and testing from borings executed to install additional instrumentation. A thorough analysis of construction documents was conducted as a part of completing the Phase 2 IES. Re\u2010evaluation of the 2014 potential failure modes based on Phase 2 IES information resulted in classifying the risk associated with Stillhouse Hollow Dam to be low. The primary risks associated with the project are concentrated leak erosion and overtopping. In the remote event of a dam breach, the primary consequence centers of Belton, Little River\u2010Academy and Cameron, Texas, would see flood wave arrival times close to 1.5\u20103 hours following the breach. Bell County, TX accounts for over 70% of the total population at risk within 60 miles of the dam. Brazoria County, TX, which is 380 miles downstream near Freeport, TX, has the greatest population at risk of any county but flood wave arrival time is greater than 5 days. In any of these unlikely scenarios, downstream flood depths would be high and the main impact areas closer to the dam would reach 36 feet above streambank with 2 hours after breach, destroying buildings and critical infrastructure. Although these communities have well practiced 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. USACE Fort Worth District regularly inspects and monitors instruments that help ensure that the structure is performing as intended and to help detect potential concerns. USACE recently added a left abutment seepage collection weir based on observations of past performance in this area and Phase 2 IES report recommendations. An automated data collection system was also added to measure spillway seepage flows at Chalk Ridge falls and select piezometers were installed during the 2017 IES investigations. A stockpile of emergency supply materials has been recently added along the right abutment of the dam. USACE Fort Worth District also 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; annually update the Stillhouse Hollow Dam Emergency Action Plan; conduct emergency exercises with state and local response teams; and communicate risks associated with Stillhouse Hollow Dam annually with stakeholders and Emergency Managers.", "riverName":"LAMPASAS RIVER", "separateStructuresCount":1, "sourceAgency":"US Army Corps of Engineers", "spillwayTypeId":3, "spillwayWidth":1650, "stateFedId":"TX00014", "stateRegulatoryAgency":null, "stateRegulatedId":0, "structuralHeight":200, "submitDate":"2023-10-26T00:00:00.000Z", "surfaceArea":6430, "volume":11804000, "widthOfLocks":0, "secondaryWidthOfLocks":null, "yearCompleted":1968, "congDist":"Congressional District 31, Texas", "city":"CAMERON", "county":"Bell", "aiannh":null, "websiteUrl":"https://www.swf-wc.usace.army.mil/stillhouse/", "coreTypeIds":"3", "damTypeIds":"8", "fedConstructionIds":"1", "fedDesignIds":"1", "fedFundingIds":"1", "fedInspectionIds":"1", "fedOperationIds":"1", "fedOtherIds":"1", "fedOwnerIds":"1", "fedRegulatoryIds":"1", "formerNames":null, "foundationTypeIds":"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":4, "femaRegion":"6", "lastEapExcerDate":"2025-02-12T12:00:00.000Z", "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":"120702", "doi_region":"ART", "doi_region_name":"Arkansas-Rio Grande-Texas Gulf", "doi_region_number":6 }, "id":191048, "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/191048?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/191048?f=jsonld" }, { "rel":"alternate", "type":"text/html", "title":"This document as HTML", "href":"https://api.wwdh.internetofwater.app/collections/usace-edr/items/191048?f=html" }, { "rel":"collection", "type":"application/json", "title":"USACE Access2Water API", "href":"https://api.wwdh.internetofwater.app/collections/usace-edr" } ] }