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"tsid":"GNGT2.Stor.Inst.0.Spillway Crest", "latest_value":229441, "units":"ac-ft", "units_long_name":"Acre-feet" }, { "slug":"stor.streambed", "label":"Streambed", "parameter":"Stor", "base_parameter":"Stor", "tsid":"GNGT2.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":"GNGT2.Stor.Inst.0.Top of Conservation", "latest_value":51822, "units":"ac-ft", "units_long_name":"Acre-feet" }, { "slug":"stor.top of dam", "label":"Top of Dam", "parameter":"Stor", "base_parameter":"Stor", "tsid":"GNGT2.Stor.Inst.0.Top of Dam", "latest_value":659786, "units":"ac-ft", "units_long_name":"Acre-feet" }, { "slug":"stor.top of flood", "label":"Top of Flood", "parameter":"Stor", "base_parameter":"Stor", "tsid":"GNGT2.Stor.Inst.0.Top of Flood", "latest_value":230481, "units":"ac-ft", "units_long_name":"Acre-feet" }, { "slug":"stor.top of inactive", "label":"Top of Inactive", "parameter":"Stor", "base_parameter":"Stor", "tsid":"GNGT2.Stor.Inst.0.Top of Inactive", "latest_value":0, "units":"ac-ft", "units_long_name":"Acre-feet" } ], "id":550044, "associatedStructuresCount":0, "conditionAssessDate":null, "conditionAssessDetail":null, "conditionAssessId":6, "damHeight":115, "damLength":15240, "distance":null, "drainageArea":475, "eapId":1, "dsacAssignedDate":"2018-05-16T12:00:00.000Z", "eapMeetsGuidelinesId":1, "emergencyContactsUpdated":"2024-09-27T12:00:00.000Z", "eapLastRevDate":"2021-03-12T12:00:00.000Z", "enforcementAuthorityId":0, "federalId":"TX08005", "oldFederalId":"TX08005", "hazardId":4, "hydraulicHeight":114, "inspectionAuthorityId":0, "inspectionDate":"2022-05-18T12:00:00.000Z", "inspectionFrequency":5, "jurisdictionAuthorityId":0, "latitude":30.701476783, "lengthOfLocks":0, "secondaryLengthOfLocks":null, "longitude":-97.329838762, "maxDischarge":342330, "maxStorage":650000, "nidHeight":115, "nidStorage":650000, "normalStorage":65500, "numberOfLocks":0, "operationalStatusDate":"2018-05-16T12:00:00.000Z", "operationalStatusId":1, "originalDesignerName":null, "otherStructureId":null, "permittingAuthorityId":0, "politicalPartyId":null, "privateDamId":null, "projectDescription":"The U.S. Army Corps of Engineers (USACE) completed construction of Granger Dam in 1980 in accordance with Flood Control Act approved September 1954 (Public Law 780, 83rd Congress, 2nd Session), and in accordance with the plan of improvement and with the recommendation of the Chief of Engineers outlined in House Document No. 535 (81st Congress, 2nd Session). In conjunction, North Fork and South Fork Reservoirs were also authorized in 1962 for construction. Granger Dam, formerly known as Laneport Reservoir, was built on the San Gabriel River to reduce the risk of flooding to mostly rural areas within 60 miles downstream of the dam, including the City of Cameron, Texas, adjacent towns and counties, and the downstream Texas cities of Sugarland and Freeport, which are located approximately 258 to 350 miles downstream. Granger Dam is located 10 miles northeast of the City of Taylor in Williamson County, Texas and reduces the risk of flooding to downstream communities by holding back waters during heavy rain events until they can be released minimizing loss of life, property or the environment. The dam consists of an earthen embankment 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 ogee weir spillway which holds water to 27\u2010feet below the top of the dam to allow water to flow out when water levels within the reservoir become high. The main dam is made up of soil and rock and is approximately 115 feet high (approximately 12 stories) at a crest elevation of 555.0 feet (NGVD29 vertical datum control). Excluding the spillway, the dam embankment is approximately 15,425.5 feet long. The reservoir is kept at or below the conservation pool elevation of 504.0 feet NGVD29 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. Granger 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, the dam also provides water supply, fish and wildlife conservation, and unique recreation opportunities. These benefits all significantly improve the quality of life in the area.", "riskCharSummary":"Even though Granger 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 Granger Dam in May 2017 that characterizes the risk associated with the project as very low. This classification is based on an unlikely event involving internal erosion of foundation gravels under the right abutment embankment of the auxiliary spillway and overtopping of the dam during extreme flooding events. The most likely scenario that could result in downstream flooding from Granger Dam are high volume releases through the uncontrolled overflow spillway during significant storm events. Such higher releases from the spillway could create conditions like how the river might behave if the dam did not exist. In the remote event of a dam breach, the largest impacts would be mostly in rural areas located within 60 miles of the dam and in the Cities of Laneport, San Gabriel, and Cameron, Texas. Although these communities have local emergency managers meeting regularly with USACE to discuss emergency response planning to flood events, including the unlikely potential for dam failure, breach of the dam would likely 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 dam is safely and properly performing. 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 annually inspects and monitors instruments that help ensure that the structure is performing as intended and help detect potential concerns. 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 updates the Granger Dam Emergency Action Plan; conducts emergency exercises with state and local response teams; and annually communicates risks associated with Granger Dam with stakeholders and Emergency Managers.", "riverName":"SAN GABRIEL RIVER", "separateStructuresCount":0, "sourceAgency":"US Army Corps of Engineers", "spillwayTypeId":3, "spillwayWidth":950, "stateFedId":"TX08005", "stateRegulatoryAgency":null, "stateRegulatedId":0, "structuralHeight":115, "submitDate":"2023-10-26T00:00:00.000Z", "surfaceArea":4400, "volume":15687500, "widthOfLocks":0, "secondaryWidthOfLocks":null, "yearCompleted":1979, "congDist":"Congressional District 31, Texas", "city":"LANEPORT", "county":"Williamson", "aiannh":null, "websiteUrl":"https://www.swf-wc.usace.army.mil/granger/", "coreTypeIds":"3", "damTypeIds":"8", "fedConstructionIds":"1", "fedDesignIds":"1", "fedFundingIds":"1", "fedInspectionIds":"1", "fedOperationIds":"1", "fedOtherIds":"1", "fedOwnerIds":"1", "fedRegulatoryIds":"1", "formerNames":"Laneport Reservoir", "foundationTypeIds":"1;3", "nonFederalDamOnFederalId":0, "designerNames":"CESWF", "otherNames":"Granger Lake", "ownerNames":"USACE - Fort Worth District", "ownerTypeIds":"3", "primaryDamTypeId":8, "primaryOwnerTypeId":3, "primaryPurposeId":8, "purposeIds":"8;4;5;9", "dsacId":5, "femaRegion":"6", "lastEapExcerDate":"2024-10-10T12:00:00.000Z", "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":179048, "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/179048?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/179048?f=jsonld" }, { "rel":"alternate", "type":"text/html", "title":"This document as HTML", "href":"https://api.wwdh.internetofwater.app/collections/usace-edr/items/179048?f=html" }, { "rel":"collection", "type":"application/json", "title":"USACE Access2Water API", "href":"https://api.wwdh.internetofwater.app/collections/usace-edr" } ] }