{ "bbox":null, "type":"Feature", "geometry":{ "bbox":null, "type":"Point", "coordinates":[ -72.31196, 42.998 ] }, "properties":{ "provider":"NAE", "code":"SMD", "slug":"smd", "elevation":485.0, "horizontal_datum":"", "vertical_datum":"NGVD29", "state":"NH", "kind":"PROJECT", "nearest_city":"Keene", "public_name":"Surry Mountain Dam", "location_code":8162021, "nsid":null, "aliases":{ "NIDID":"NH00007", "CWMS Legacy Naming":"SMD", "CWMS Standard Naming":"SMD", "USGS Station Number":"01158000" }, "timeseries":[ { "tsid":"SMD.Stage-Pool.Inst.15Minutes.0.DCP-rev", "label":"Stage", "base_parameter":"Stage", "parameter":"Stage-Pool", "unit":"ft", "unit_long_name":"Feet", "latest_time":"2026-08-25T22:00:00Z", "latest_value":6.39, "delta24h":null, "sort_order":4, "results":null }, { "tsid":"SMD.Stage-TAILWATER.Inst.15Minutes.0.DCP-rev", "label":"Stage Tailwater", "base_parameter":"Stage", "parameter":"Stage-TAILWATER", "unit":"ft", "unit_long_name":"Feet", "latest_time":"2026-08-25T22:00:00Z", "latest_value":4.66, "delta24h":null, "sort_order":5, "results":null }, { "tsid":"SMD.Flow-Inflow.Inst.6Hours.0.Forecast", "label":"Inflow", "base_parameter":"Flow", "parameter":"Flow-Inflow", "unit":"cfs", "unit_long_name":"Cubic feet per second", "latest_time":"2026-08-26T00:00:00Z", "latest_value":0.0, "delta24h":null, "sort_order":6, "results":null }, { "tsid":"SMD.Flow.Inst.15Minutes.0.DCP-rev", "label":"Outflow", "base_parameter":"Flow", "parameter":"Flow", "unit":"cfs", "unit_long_name":"Cubic feet per second", "latest_time":"2026-08-25T22:00:00Z", "latest_value":12.82, "delta24h":null, "sort_order":7, "results":null }, { "tsid":"SMD.Precip.Inst.15Minutes.0.DCP-rev", "label":"Precipitation", "base_parameter":"Precip", "parameter":"Precip", "unit":"in", "unit_long_name":"Inches", "latest_time":"2026-08-25T22:00:00Z", "latest_value":31.26, "delta24h":null, "sort_order":16, "results":null }, { "tsid":"SMD.Temp-Air.Inst.15Minutes.0.DCP-rev", "label":"Air Temperature", "base_parameter":"Temp", "parameter":"Temp-Air", "unit":"F", "unit_long_name":"Fahrenheit", "latest_time":"2026-08-25T22:00:00Z", "latest_value":71.3, "delta24h":null, "sort_order":22, "results":null }, { "tsid":"SMD.Stor.Inst.15Minutes.0.DCP-rev", "label":"Flood Storage", "base_parameter":"Stor", "parameter":"Stor", "unit":"ac-ft", "unit_long_name":"Acre-feet", "latest_time":"2026-08-25T22:00:00Z", "latest_value":0.0, "delta24h":null, "sort_order":11, "results":null } ], "name":"Surry Mountain Dam", "hasResopsAverages":"false", "nidId":"NH00007", "nidid":"", "levels":[ { "slug":"stage.bottom of normal", "label":"Bottom of Normal", "parameter":"Stage-Pool", "base_parameter":"Stage", "tsid":"SMD.Stage-Pool.Inst.0.Bottom of Normal", "latest_value":14.5, "units":"ft", "units_long_name":"Feet", "type":"CONSTANT" }, { "slug":"stage.spillway crest", "label":"Spillway Crest", "parameter":"Stage-Pool", "base_parameter":"Stage", "tsid":"SMD.Stage-Pool.Inst.0.Spillway Crest", "latest_value":65, "units":"ft", "units_long_name":"Feet", "type":"CONSTANT" }, { "slug":"stage.streambed", "label":"Streambed", "parameter":"Stage-Pool", "base_parameter":"Stage", "tsid":"SMD.Stage-Pool.Inst.0.Streambed", "latest_value":0, "units":"ft", "units_long_name":"Feet", "type":"CONSTANT" }, { "slug":"stage.top of dam", "label":"Top of Dam", "parameter":"Stage-Pool", "base_parameter":"Stage", "tsid":"SMD.Stage-Pool.Inst.0.Top of Dam", "latest_value":83, "units":"ft", "units_long_name":"Feet", "type":"CONSTANT" }, { "slug":"stage.top of flood", "label":"Top of Flood", "parameter":"Stage-Pool", "base_parameter":"Stage", "tsid":"SMD.Stage-Pool.Inst.0.Top of Flood", "latest_value":65, "units":"ft", "units_long_name":"Feet", "type":"CONSTANT" }, { "slug":"stage.top of normal", "label":"Top of Normal", "parameter":"Stage-Pool", "base_parameter":"Stage", "tsid":"SMD.Stage-Pool.Inst.0.Top of Normal", "latest_value":14.5, "units":"ft", "units_long_name":"Feet", "type":"CONSTANT" }, { "slug":"stor.bottom of normal", "label":"Bottom of Normal", "parameter":"Stor", "base_parameter":"Stor", "tsid":"SMD.Stor.Inst.0.Bottom of Normal", "latest_value":1, "units":"ac-ft", "units_long_name":"Acre-feet", "type":"CONSTANT" }, { "slug":"stor.top of flood", "label":"Top of Flood", "parameter":"Stor", "base_parameter":"Stor", "tsid":"SMD.Stor.Inst.0.Top of Flood", "latest_value":32500, "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":"SMD.Stor.Inst.0.Top of Normal", "latest_value":1, "units":"ac-ft", "units_long_name":"Acre-feet", "type":"CONSTANT" } ], "id":550194, "associatedStructuresCount":0, "conditionAssessDate":null, "conditionAssessDetail":null, "conditionAssessId":6, "damHeight":83, "damLength":1800, "distance":null, "drainageArea":100, "eapId":1, "dsacAssignedDate":"2019-04-25T12:00:00.000Z", "eapMeetsGuidelinesId":0, "emergencyContactsUpdated":"2024-12-20T12:00:00.000Z", "eapLastRevDate":"2021-03-30T12:00:00.000Z", "enforcementAuthorityId":1, "federalId":"NH00007", "oldFederalId":"NH00007", "hazardId":4, "hydraulicHeight":77, "inspectionAuthorityId":1, "inspectionDate":"2023-06-01T12:00:00.000Z", "inspectionFrequency":5, "jurisdictionAuthorityId":1, "latitude":42.9977804660001, "lengthOfLocks":0, "secondaryLengthOfLocks":null, "longitude":-72.309261098, "maxDischarge":50000, "maxStorage":44000, "nidHeight":83, "nidStorage":44000, "normalStorage":1320, "numberOfLocks":0, "operationalStatusDate":"2019-04-25T12:00:00.000Z", "operationalStatusId":2, "originalDesignerName":null, "otherStructureId":null, "permittingAuthorityId":1, "politicalPartyId":null, "privateDamId":null, "projectDescription":"The U.S. Army Corps of Engineers (USACE) built Surry Mountain Dam in 1939 to 1941 across the Ashuelot River. Surry Mountain Dam holds a 260-acre recreation pool outside of flood events. The dam holds back additional water during flood events and works together with nearby Otter Brook Dam to reduce the risk of downstream flooding on the Ashuelot and Connecticut Rivers. The dam was built in response to the severe flooding that occurred in the region in the 1930\u2019s. Since it began operations, the dam has reduced damage caused by downstream flooding by more than $541 million.\n\nThe dam is made of compacted earth and rock fill and is approximately 9 stories (86 feet) high. A 10-foot diameter concrete pipe called a conduit passes through the dam. Metal gates at the upstream side of the conduit are opened to allow water to pass through the dam and are closed when water needs to be stored during flood events. To maintain the structural integrity of the dam when the water level in the reservoir gets high, water can also be released across the spillway, a sloped concrete structure located at the west end of the dam. A spillway is similar in concept to a sink overflow that prevents a sink bowl from completely overflowing. The spillway is approximately one football field in length and approximately two stories below the top of the dam.", "riskCharSummary":"USACE completed a risk assessment of Surry Mountain Dam in 2018 and has classified the risks associated with the dam as Moderate. The dam significantly reduces the risk of flooding to surrounding communities. However, it does not entirely eliminate the risk. The most likely scenario that could result in downstream flooding from Surry Mountain Dam would be an uncontrolled high volume release of water from the dam's spillway during significant storm events. The amount of water being released could be great enough to cause flooding in downstream communities. Such higher releases from the spillway could create conditions similar to how the river might behave during a flood event if the dam did not exist. \n\nThere are also two extremely unlikely, but far more devastating scenarios that would result in failure of the dam and downstream flooding: (1) A flood so large that the capacity of the dam to store water is exceeded, resulting in flows over the top of the dam, even with maximum possible releases being made through the conduit, and (2) a flood so large that water flowing over the spillway damages the spillway structure. Were either of these events to occur, an uncontrolled surge of water would flow out of the reservoir, flooding downstream communities. Keene, Swanzey, Winchester, and Hinsdale, NH are the major areas in immediate danger in the event of the flood. Towns and cities further downstream, including Hartford, CT would also be impacted, but less so. \n\nEven though very unlikely, if any of the scenarios described above were to occur, the downstream floodwater would be swift and deep, destroying buildings and key infrastructure, and those caught unaware and/or unable to evacuate could perish. In the less likely dam breach scenarios, the water depth, property damage, and lives lost would likely be far greater than flooding due to spillway discharges. In a worst case scenario, you could see water higher than a two story building.", "riskManagementMeasures":"No emergency situation currently exists at Surry Mountain Dam. Should a crisis occur, we will use our expertise to quickly find a solution to resume operations. While we cannot completely eliminate risk, we are taking actions to further reduce the risks. We closely monitor the performance of Surry Mountain Dam and will modify operations if we feel there is risk to the public. We will continue to work closely with state and local emergency managers, conducting emergency exercises, and incorporate any new information into our Emergency Action Plan for the dam. We will also continue our rigorous monitoring and surveillance of the dam, especially during high water events. We closely follow rainfall forecasts to determine when high water events may occur so that necessary flood warnings may be issued in a timely manner. USACE is planning for additional studies to further understand the risk associated with Surry Mountain Dam, and what, if any, actions can be completed to reduce the risk.", "riverName":"ASHUELOT RIVER", "separateStructuresCount":0, "sourceAgency":"US Army Corps of Engineers", "spillwayTypeId":3, "spillwayWidth":338, "stateFedId":"NH00007", "stateRegulatoryAgency":"NH DES", "stateRegulatedId":1, "structuralHeight":83, "submitDate":"2023-02-16T17:25:15.070Z", "surfaceArea":260, "volume":1118000, "widthOfLocks":0, "secondaryWidthOfLocks":null, "yearCompleted":1941, "congDist":"Congressional District 02, New Hampshire", "city":"SURRY", "county":"Cheshire", "aiannh":null, "websiteUrl":"https://www.nae.usace.army.mil/Missions/Civil-Works/Flood-Risk-Management/New-Hampshire/Surry/", "coreTypeIds":"3", "damTypeIds":"5;8;9", "fedConstructionIds":"1", "fedDesignIds":"1", "fedFundingIds":"1", "fedInspectionIds":"1", "fedOperationIds":"1", "fedOtherIds":"1", "fedOwnerIds":"1", "fedRegulatoryIds":"1", "formerNames":null, "foundationTypeIds":"1;3", "nonFederalDamOnFederalId":0, "designerNames":"CENAE", "otherNames":"Surry Mountain Lake", "ownerNames":"USACE - New England District", "ownerTypeIds":"3", "primaryDamTypeId":5, "primaryOwnerTypeId":3, "primaryPurposeId":9, "purposeIds":"9;5", "dsacId":3, "femaRegion":"1", "lastEapExcerDate":"2024-04-05T12:00:00.000Z", "dataUpdated":"2025-03-17T12:00:00.000Z", "usaceDistrict":"New England District", "noConsequencesId":0, "secretaryAgricultureBuiltId":null, "nrcsWatershedAuthorizationId":null, "isAssociatedStructureId":"No", "fedRegulatedId":"Yes", "inundationNidAddedId":1, "damStatusId":2, "huc06":"010802", "doi_region":null, "doi_region_name":"North Atlantic-Appalachian", "doi_region_number":1 }, "id":8162021, "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/8162021?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/8162021?f=jsonld" }, { "rel":"alternate", "type":"text/html", "title":"This document as HTML", "href":"https://api.wwdh.internetofwater.app/collections/usace-edr/items/8162021?f=html" }, { "rel":"collection", "type":"application/json", "title":"USACE Access2Water API", "href":"https://api.wwdh.internetofwater.app/collections/usace-edr" } ] }