{ "bbox":null, "type":"Feature", "geometry":{ "bbox":null, "type":"Point", "coordinates":[ -71.7231, 43.3156 ] }, "properties":{ "provider":"NAE", "code":"BWD", "slug":"bwd", "elevation":514.99, "horizontal_datum":"WGS84", "vertical_datum":"", "state":"NH", "kind":"PROJECT", "nearest_city":"Concord", "public_name":"Blackwater Dam", "location_code":8033021, "nsid":null, "aliases":{ "NIDID":"NH00001", "CWMS Legacy Naming":"BWD", "CWMS Standard Naming":"BWD", "USGS Station Number":"01087000" }, "timeseries":[ { "tsid":"BWD.Stor.Inst.15Minutes.0.DCP-rev", "label":"Flood Storage", "base_parameter":"Stor", "parameter":"Stor", "unit":"ac-ft", "unit_long_name":"Acre-feet", "latest_time":"2026-08-25T21:30:00Z", "latest_value":5.15, "delta24h":null, "sort_order":11, "results":null }, { "tsid":"BWD.Flow-Inflow.Total.15Minutes.6Hours.DCP-rev", "label":"Inflow", "base_parameter":"Flow", "parameter":"Flow-Inflow", "unit":"cfs", "unit_long_name":"Cubic feet per second", "latest_time":"2026-08-25T21:30:00Z", "latest_value":23.6, "delta24h":null, "sort_order":6, "results":null }, { "tsid":"BWD.Stage-TAILWATER.Inst.15Minutes.0.DCP-rev", "label":"Stage Tailwater", "base_parameter":"Stage", "parameter":"Stage-TAILWATER", "unit":"ft", "unit_long_name":"Feet", "latest_time":"2026-08-25T21:30:00Z", "latest_value":2.03, "delta24h":null, "sort_order":5, "results":null }, { "tsid":"BWD.Flow.Inst.15Minutes.0.DCP-rev", "label":"Outflow", "base_parameter":"Flow", "parameter":"Flow", "unit":"cfs", "unit_long_name":"Cubic feet per second", "latest_time":"2026-08-25T21:30:00Z", "latest_value":23.6, "delta24h":null, "sort_order":7, "results":null }, { "tsid":"BWD.Elev-Pool.Inst.15Minutes.0.DCP-rev", "label":"Elevation", "base_parameter":"Elev", "parameter":"Elev-Pool", "unit":"ft", "unit_long_name":"Feet", "latest_time":"2026-08-25T21:30:00Z", "latest_value":515.51, "delta24h":null, "sort_order":1, "results":null }, { "tsid":"BWD.Precip.Inst.15Minutes.0.DCP-rev", "label":"Precipitation", "base_parameter":"Precip", "parameter":"Precip", "unit":"in", "unit_long_name":"Inches", "latest_time":"2026-08-25T21:30:00Z", "latest_value":26.92, "delta24h":null, "sort_order":16, "results":null } ], "name":"Blackwater Dam", "hasResopsAverages":"false", "nidId":"NH00001", "nidid":"", "levels":[ { "slug":"elev.bottom of normal", "label":"Bottom of Normal", "parameter":"Elev-Pool", "base_parameter":"Elev", "tsid":"BWD.Elev-Pool.Inst.0.Bottom of Normal", "latest_value":515, "units":"ft", "units_long_name":"Feet", "type":"CONSTANT" }, { "slug":"elev.top of flood", "label":"Top of Flood", "parameter":"Elev-Pool", "base_parameter":"Elev", "tsid":"BWD.Elev-Pool.Inst.0.Top of Flood", "latest_value":566, "units":"ft", "units_long_name":"Feet", "type":"CONSTANT" }, { "slug":"elev.top of normal", "label":"Top of Normal", "parameter":"Elev-Pool", "base_parameter":"Elev", "tsid":"BWD.Elev-Pool.Inst.0.Top of Normal", "latest_value":516, "units":"ft", "units_long_name":"Feet", "type":"CONSTANT" }, { "slug":"elev.streambed", "label":"Streambed", "parameter":"Elev", "base_parameter":"Elev", "tsid":"BWD.Elev.Inst.0.Streambed", "latest_value":515, "units":"ft", "units_long_name":"Feet", "type":"CONSTANT" }, { "slug":"elev.top of dam", "label":"Top of Dam", "parameter":"Elev", "base_parameter":"Elev", "tsid":"BWD.Elev.Inst.0.Top of Dam", "latest_value":584, "units":"ft", "units_long_name":"Feet", "type":"CONSTANT" }, { "slug":"elev.top of flood", "label":"Top of Flood", "parameter":"Elev", "base_parameter":"Elev", "tsid":"BWD.Elev.Inst.0.Top of Flood", "latest_value":566, "units":"ft", "units_long_name":"Feet", "type":"CONSTANT" }, { "slug":"stor.top of flood", "label":"Top of Flood", "parameter":"Stor", "base_parameter":"Stor", "tsid":"BWD.Stor.Inst.0.Top of Flood", "latest_value":46000, "units":"ac-ft", "units_long_name":"Acre-feet", "type":"CONSTANT" }, { "slug":"stor.top of normal", "label":"Top of Normal", "parameter":"Stor", "base_parameter":"Stor", "tsid":"BWD.Stor.Inst.0.Top of Normal", "latest_value":10, "units":"ac-ft", "units_long_name":"Acre-feet", "type":"CONSTANT" } ], "id":550183, "associatedStructuresCount":0, "conditionAssessDate":null, "conditionAssessDetail":null, "conditionAssessId":6, "damHeight":75, "damLength":1150, "distance":null, "drainageArea":128, "eapId":1, "dsacAssignedDate":"2018-11-26T12:00:00.000Z", "eapMeetsGuidelinesId":1, "emergencyContactsUpdated":"2024-12-20T12:00:00.000Z", "eapLastRevDate":"2021-06-02T12:00:00.000Z", "enforcementAuthorityId":1, "federalId":"NH00001", "oldFederalId":"NH00001", "hazardId":4, "hydraulicHeight":64, "inspectionAuthorityId":1, "inspectionDate":"2022-10-25T12:00:00.000Z", "inspectionFrequency":5, "jurisdictionAuthorityId":1, "latitude":43.316114607, "lengthOfLocks":0, "secondaryLengthOfLocks":null, "longitude":-71.722189214, "maxDischarge":42800, "maxStorage":93400, "nidHeight":75, "nidStorage":93400, "normalStorage":0, "numberOfLocks":0, "operationalStatusDate":"2018-11-26T12:00:00.000Z", "operationalStatusId":1, "originalDesignerName":null, "otherStructureId":null, "permittingAuthorityId":1, "politicalPartyId":null, "privateDamId":null, "projectDescription":"The U.S. Army Corps of Engineers (USACE) operates and maintains more than 700 dams across the United States. A dam is an earthen embankment and/or solid concrete structure that is built across a river, stream, or other waterway to temporarily hold back and store water that would otherwise flow downstream. More detail related to this specific dam will be added at a future time.", "riskCharSummary":"Dams do not eliminate all risk of flooding. USACE works to address all types of flood risk associated with the dam. Dams have limited capacity to store water. Water may be released through the dam to manage water levels up or downstream or to relieve pressure on the dam to maintain its structural integrity. Severe weather events that bring inconsistent or larger amounts of water into the system can also lead to dam releases or in some cases overwhelm and lead to issues occurring at a dam. \n\nAlthough Blackwater Dam educes the risk of flooding to downstream communities, the dam does not eliminate the risk of flooding. Blackwater Dam is designed to manage peak flooding levels downstream without risking the structural integrity of the dam. The most likely scenario that could result in downstream flooding is high volume releases from Blackwater Dam through the ungated spillway during high water events. This type of water release occurs when the reservoir's flood storage capacity is exceeded and excess water flows through the spillway. Water moving through the spillway during the largest expected flood in the watershed would put thousands of people at risk and flood waters could be as deep as a four-story building. While weather can be unpredictable, this type of event can often be predicted 1-2 days before flood waters would impact downstream communities. USACE will engage state emergency managers when such an event is forecasted and support actions to get people to safety.\n\nUSACE completed a risk assessment in 2018 and classified the risks associated with the Blackwater Dam as low. This classification is based on the large population that lives immediately downstream of the dam in Webster and Contoocook, NH, as well as smaller communities along the Merrimack River. Two unlikely, but devastating scenarios that would produce significant downstream flooding are breach of the dam due to water flowing over the top of the dam or embankment erosion leading to breach. In the case of an extremely rare and large rain event, water could potentially flow over the top of the dam, which could cause erosion of the earthen embankment, and breach of the dam. In addition, internal erosion of the embankment could create a flow path through the dam, which could eventually allow the crest to collapse. In these scenarios, Webster and Contoocook, along with smaller communities along the river, would be the most impacted. Downstream flooding in Webster would occur less than an hour after of breach and the rapidly moving water could be as deep as 31 feet, destroying buildings and critical infrastructure. In addition, some evacuation routes would be under water, increasing evacuation distances. The estimated potential incremental life loss associated with a failure of the dam is up to 52 people. \n\nThe risk of failure of the two dikes is also considered to be low. It is driven by the possibility of leaking through the embankment leading to internal erosion, then breach. The area likely to be impacted by dike failure is the valley between the dikes and Contoocook, NH. The estimated potential incremental life loss associated with a failure of a dike is up to 17 people.", "riskManagementMeasures":"USACE manages dam-related flood risks by continually monitoring the condition and health of the dam, prioritizing activities that will most impact the risks, and engaging upstream and downstream emergency managers and members of the public to raise awareness of the dam and support actions to prepare and be ready to respond in the case of a dam-related emergency. USACE works closely with local emergency managers to share what is known about the dam and support the development of local emergency and evacuation plans. USACE regularly updates the emergency action plan for the dam. Regular maintenance and repairs are performed as needed to keep the dam functioning properly. \n\nBlackwater Dam is operated in conjunction with Franklin Falls Dam, and is staffed full time. During high pools, Blackwater Dam is inspected on a daily basis. When the pool continues to rise, engineers conduct a site visit to evaluate dam performance. Geotechnical instrumentation data is reviewed regularly during normal pools and more frequently during high pools.", "riverName":"BLACKWATER RIVER", "separateStructuresCount":2, "sourceAgency":"US Army Corps of Engineers", "spillwayTypeId":3, "spillwayWidth":241, "stateFedId":"NH00001", "stateRegulatoryAgency":"NH DES", "stateRegulatedId":1, "structuralHeight":69, "submitDate":"2023-02-16T17:25:11.672Z", "surfaceArea":1, "volume":299000, "widthOfLocks":0, "secondaryWidthOfLocks":null, "yearCompleted":1941, "congDist":"Congressional District 02, New Hampshire", "city":"WEBSTER", "county":"Merrimack", "aiannh":null, "websiteUrl":"https://www.nae.usace.army.mil/Missions/Civil-Works/Flood-Risk-Management/New-Hampshire/Blackwater/", "coreTypeIds":"3", "damTypeIds":"9;8", "fedConstructionIds":"1", "fedDesignIds":"1", "fedFundingIds":"1", "fedInspectionIds":"1", "fedOperationIds":"1", "fedOtherIds":"1", "fedOwnerIds":"1", "fedRegulatoryIds":"1", "formerNames":"Dodge Estate Dike", "foundationTypeIds":"1", "nonFederalDamOnFederalId":0, "designerNames":"CENAE", "otherNames":"Dry Reservoir", "ownerNames":"USACE - New England District", "ownerTypeIds":"3", "primaryDamTypeId":9, "primaryOwnerTypeId":3, "primaryPurposeId":9, "purposeIds":"9", "dsacId":4, "femaRegion":"1", "lastEapExcerDate":"2024-09-05T12:00:00.000Z", "dataUpdated":"2025-01-21T12:00:00.000Z", "usaceDistrict":"New England District", "noConsequencesId":0, "secretaryAgricultureBuiltId":null, "nrcsWatershedAuthorizationId":null, "isAssociatedStructureId":"No", "fedRegulatedId":"Yes", "inundationNidAddedId":1, "damStatusId":2, "huc06":"010700", "doi_region":null, "doi_region_name":"North Atlantic-Appalachian", "doi_region_number":1 }, "id":8033021, "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/8033021?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/8033021?f=jsonld" }, { "rel":"alternate", "type":"text/html", "title":"This document as HTML", "href":"https://api.wwdh.internetofwater.app/collections/usace-edr/items/8033021?f=html" }, { "rel":"collection", "type":"application/json", "title":"USACE Access2Water API", "href":"https://api.wwdh.internetofwater.app/collections/usace-edr" } ] }