{ "bbox":null, "type":"Feature", "geometry":{ "bbox":null, "type":"Point", "coordinates":[ -81.2261, 40.3558 ] }, "properties":{ "provider":"LRH", "code":"Tappan", "slug":"tappan", "elevation":870.0, "horizontal_datum":"WGS84", "vertical_datum":"NGVD29", "state":"OH", "kind":"PROJECT", "nearest_city":"Feed Springs", "public_name":"Tappan Lake", "location_code":578108, "nsid":null, "aliases":{ "Local Loc ID":"TAL", "NIDID":"OH00010" }, "timeseries":[ { "tsid":"Tappan-Lake.Flow.Inst.15Minutes.0.OBS", "label":"Inflow", "base_parameter":"Flow", "parameter":"Flow", "unit":"cfs", "unit_long_name":"Cubic feet per second", "latest_time":"2026-04-14T22:15:00Z", "latest_value":32.13, "delta24h":null, "sort_order":6, "results":null }, { "tsid":"Tappan-Lake.Elev.Inst.15Minutes.0.OBS", "label":"Elevation", "base_parameter":"Elev", "parameter":"Elev", "unit":"ft", "unit_long_name":"Feet", "latest_time":"2026-04-14T22:15:00Z", "latest_value":899.85, "delta24h":null, "sort_order":1, "results":null }, { "tsid":"Tappan-Outflow.Stage.Inst.15Minutes.0.OBS", "label":"Stage Tailwater", "base_parameter":"Stage", "parameter":"Stage", "unit":"ft", "unit_long_name":"Feet", "latest_time":"2026-04-14T22:15:00Z", "latest_value":4.41, "delta24h":null, "sort_order":5, "results":null }, { "tsid":"Tappan-Lake.Stor.Inst.15Minutes.0.OBS", "label":"Conservation Storage", "base_parameter":"Stor", "parameter":"Stor", "unit":"ac-ft", "unit_long_name":"Acre-feet", "latest_time":"2026-04-14T22:15:00Z", "latest_value":36440.0, "delta24h":null, "sort_order":13, "results":null }, { "tsid":"Tappan-Outflow.Flow.Inst.15Minutes.0.OBS", "label":"Outflow", "base_parameter":"Flow", "parameter":"Flow", "unit":"cfs", "unit_long_name":"Cubic feet per second", "latest_time":"2026-04-14T22:15:00Z", "latest_value":32.13, "delta24h":null, "sort_order":7, "results":null }, { "tsid":"Tappan-Lake.Stor.Inst.15Minutes.0.OBS", "label":"Flood Storage", "base_parameter":"Stor", "parameter":"Stor", "unit":"ac-ft", "unit_long_name":"Acre-feet", "latest_time":"2026-04-14T22:15:00Z", "latest_value":36440.0, "delta24h":null, "sort_order":11, "results":null }, { "tsid":"Tappan-Outflow.Elev.Inst.15Minutes.0.OBS", "label":"Elevation Tailwater", "base_parameter":"Elev", "parameter":"Elev", "unit":"ft", "unit_long_name":"Feet", "latest_time":"2026-04-14T22:15:00Z", "latest_value":865.41, "delta24h":null, "sort_order":3, "results":null }, { "tsid":"Tappan-Lake.Elev.Inst.1Day.0.RUL", "label":"Elevation Rule Curve", "base_parameter":"Elev", "parameter":"Elev", "unit":"ft", "unit_long_name":"Feet", "latest_time":"2026-04-14T17:00:00Z", "latest_value":899.3, "delta24h":null, "sort_order":2, "results":null } ], "name":"Tappan Lake", "hasResopsAverages":"true", "nidId":"OH00010", "nidid":"", "levels":[ { "slug":"elev.bottom of conservation", "label":"Bottom of Conservation", "parameter":"Elev", "base_parameter":"Elev", "tsid":"Tappan.Elev.Inst.0.Bottom of Conservation", "latest_value":870, "units":"ft", "units_long_name":"Feet" }, { "slug":"elev.bottom of flood", "label":"Bottom of Flood", "parameter":"Elev", "base_parameter":"Elev", "tsid":"Tappan.Elev.Inst.0.Bottom of Flood", "latest_value":899.3, "units":"ft", "units_long_name":"Feet" }, { "slug":"elev.streambed", "label":"Streambed", "parameter":"Elev", "base_parameter":"Elev", "tsid":"Tappan.Elev.Inst.0.Streambed", "latest_value":868, "units":"ft", "units_long_name":"Feet" }, { "slug":"elev.top of dam", "label":"Top of Dam", "parameter":"Elev", "base_parameter":"Elev", "tsid":"Tappan.Elev.Inst.0.Top of Dam", "latest_value":924.4, "units":"ft", "units_long_name":"Feet" }, { "slug":"elev.top of flood", "label":"Top of Flood", "parameter":"Elev", "base_parameter":"Elev", "tsid":"Tappan.Elev.Inst.0.Top of Flood", "latest_value":909, "units":"ft", "units_long_name":"Feet" }, { "slug":"elev.top of flood threat", "label":"Top of Flood Threat", "parameter":"Elev", "base_parameter":"Elev", "tsid":"Tappan.Elev.Inst.0.Top of Flood Threat", "latest_value":902, "units":"ft", "units_long_name":"Feet" }, { "slug":"elev.top of inactive", "label":"Top of Inactive", "parameter":"Elev", "base_parameter":"Elev", "tsid":"Tappan.Elev.Inst.0.Top of Inactive", "latest_value":870, "units":"ft", "units_long_name":"Feet" }, { "slug":"elev.top of normal", "label":"Top of Normal", "parameter":"Elev", "base_parameter":"Elev", "tsid":"Tappan.Elev.Inst.0.Top of Normal", "latest_value":899.3, "units":"ft", "units_long_name":"Feet" }, { "slug":"elev.top of record", "label":"Top of Record", "parameter":"Elev", "base_parameter":"Elev", "tsid":"Tappan.Elev.Inst.0.Top of Record", "latest_value":905.55, "units":"ft", "units_long_name":"Feet" }, { "slug":"elev.top of recreation", "label":"Top of Recreation", "parameter":"Elev", "base_parameter":"Elev", "tsid":"Tappan.Elev.Inst.0.Top of Recreation", "latest_value":899.3, "units":"ft", "units_long_name":"Feet" }, { "slug":"stor.top of conservation", "label":"Top of Conservation", "parameter":"Stor", "base_parameter":"Stor", "tsid":"Tappan.Stor.Inst.0.Top of Conservation", "latest_value":35081, "units":"ac-ft", "units_long_name":"Acre-feet" }, { "slug":"stor.top of dam", "label":"Top of Dam", "parameter":"Stor", "base_parameter":"Stor", "tsid":"Tappan.Stor.Inst.0.Top of Dam", "latest_value":121440, "units":"ac-ft", "units_long_name":"Acre-feet" }, { "slug":"stor.top of flood", "label":"Top of Flood", "parameter":"Stor", "base_parameter":"Stor", "tsid":"Tappan.Stor.Inst.0.Top of Flood", "latest_value":61600, "units":"ac-ft", "units_long_name":"Acre-feet" }, { "slug":"stor.top of inactive", "label":"Top of Inactive", "parameter":"Stor", "base_parameter":"Stor", "tsid":"Tappan.Stor.Inst.0.Top of Inactive", "latest_value":46, "units":"ac-ft", "units_long_name":"Acre-feet" }, { "slug":"stor.top of normal", "label":"Top of Normal", "parameter":"Stor", "base_parameter":"Stor", "tsid":"Tappan.Stor.Inst.0.Top of Normal", "latest_value":35100, "units":"ac-ft", "units_long_name":"Acre-feet" } ], "id":550245, "associatedStructuresCount":0, "conditionAssessDate":null, "conditionAssessDetail":null, "conditionAssessId":6, "damHeight":null, "damLength":1550, "distance":7, "drainageArea":71, "eapId":1, "dsacAssignedDate":"2018-11-26T12:00:00.000Z", "eapMeetsGuidelinesId":1, "emergencyContactsUpdated":"2024-07-25T12:00:00.000Z", "eapLastRevDate":"2009-09-16T12:00:00.000Z", "enforcementAuthorityId":0, "federalId":"OH00010", "oldFederalId":"OH00010", "hazardId":4, "hydraulicHeight":45, "inspectionAuthorityId":0, "inspectionDate":"2024-04-04T12:00:00.000Z", "inspectionFrequency":5, "jurisdictionAuthorityId":0, "latitude":40.3588845560001, "lengthOfLocks":0, "secondaryLengthOfLocks":null, "longitude":-81.226639652, "maxDischarge":23700, "maxStorage":61600, "nidHeight":52, "nidStorage":61600, "normalStorage":35100, "numberOfLocks":0, "operationalStatusDate":"2018-11-26T12:00:00.000Z", "operationalStatusId":1, "originalDesignerName":null, "otherStructureId":null, "permittingAuthorityId":0, "politicalPartyId":null, "privateDamId":null, "projectDescription":"Flood control structures at the Tappan Lake Project includes an embankment with a parapet wall, an outlet works, and an uncontrolled saddle spillway.", "riskCharSummary":"The dam significantly reduces the risk of flooding to surrounding communities; however, it does not entirely eliminate the risk. Although Tappan Dam has historically performed well, extreme rain events may cause areas downstream to be flooded. Even when the dam operates as intended, downstream flooding could still occur in a very large rainfall event. An event such as this could require unusually large quantities of water to be released. \n\nA 2024 risk assessment for Tappan Dam classified the risk of failure for the entire project system as low. The risk categorization is based on the risk of rare storm events occurring which would cause more rainfall than the dam can store safely. During such an event, the uncontrolled spillway 800 feet south of the left abutment of the dam has the potential to pass up to 33, 250 cubic feet of water per second. The uncontrolled spillway is designed to pass water to prevent the dam from overtopping and potentially breaching.\n\nWhile the Tappan Dam spillway has never flowed. If operated, it could result in significant flooding in downstream communities from Dennison, OH to Coshocton, OH. Depending on the amount of water released, significant damages to houses, buildings, factories, roads, bridges, power, and water supply may occur. Critical infrastructure, including roadways (evacuation routes) and bridges along Little Stillwater Creek, Stillwater Creek, and the Tuscarawas Creek, may not be passable due to high flood waters during spillway flows. Although the odds of such a storm even occurring are considered extremely unlikely, Tappan Dam has an emergency action plan to lower the risk of life loss if any unanticipated scenarios were to occur. \n\nWhile rare events like these have not occurred to date, if they were to happen, water is likely to reach high elevations quickly and be more than tens of feet deep depending on the location. In the rare event Tappan Dam must pass these extreme flows, follow all directions from emergency officials, including evacuation orders. Failure to do so puts you and your family\u2019s lives at risk.", "riskManagementMeasures":"There are numerous activities that U.S. Army Corps of Engineers conducts on a day-to-day basis to help manage risk at Tappan Dam. The dam is well maintained through continuous operations and maintenance activities, and the U.S. Army Corps of Engineers conducts detailed inspections of the dam during both normal lake levels and during flood events. Supplementing these inspections, the dam has a specialized instrumentation and monitoring system to allow U.S. Army Corps of Engineers staff to continually evaluate the dam for changing conditions. Risk management and emergency response actions are being supported by conducting emergency exercises and dam safety training with U.S. Army Corps of Engineers staff and local and state emergency responders. Additionally, the dam\u2019s Emergency Action Plan is routinely updated to improve emergency response actions, and flood fighting materials are stored onsite in case of an emergency.", "riverName":"LITTLE STILLWATER CREEK", "separateStructuresCount":0, "sourceAgency":"US Army Corps of Engineers", "spillwayTypeId":3, "spillwayWidth":250, "stateFedId":"OH00010", "stateRegulatoryAgency":null, "stateRegulatedId":0, "structuralHeight":52, "submitDate":"2023-12-11T20:53:46.281Z", "surfaceArea":2350, "volume":644500, "widthOfLocks":0, "secondaryWidthOfLocks":null, "yearCompleted":1936, "congDist":"Congressional District 06, Ohio", "city":"DENNISON", "county":"Harrison", "aiannh":null, "websiteUrl":"https://www.lrh.usace.army.mil/Missions/Civil-Works/Dam-Safety-Program/", "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":"CELRH", "otherNames":"Tappan Lake", "ownerNames":"USACE - Huntington District", "ownerTypeIds":"3", "primaryDamTypeId":8, "primaryOwnerTypeId":3, "primaryPurposeId":9, "purposeIds":"9;4;5", "dsacId":4, "femaRegion":"5", "lastEapExcerDate":"2024-07-25T12:00:00.000Z", "dataUpdated":"2025-04-23T12:00:00.000Z", "usaceDistrict":"Huntington District", "noConsequencesId":0, "secretaryAgricultureBuiltId":null, "nrcsWatershedAuthorizationId":null, "isAssociatedStructureId":"No", "fedRegulatedId":"Yes", "inundationNidAddedId":1, "damStatusId":2, "huc06":"050400", "doi_region":null, "doi_region_name":"Great Lakes", "doi_region_number":3, "thirtyYearAverage":44.1033, "tenthPercentile":42.6026, "ninetiethPercentile":45.9554 }, "id":578108, "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/578108?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/578108?f=jsonld" }, { "rel":"alternate", "type":"text/html", "title":"This document as HTML", "href":"https://api.wwdh.internetofwater.app/collections/usace-edr/items/578108?f=html" }, { "rel":"collection", "type":"application/json", "title":"USACE Access2Water API", "href":"https://api.wwdh.internetofwater.app/collections/usace-edr" } ] }