{ "bbox":null, "type":"Feature", "geometry":{ "bbox":null, "type":"Point", "coordinates":[ -91.52778, 41.72472 ] }, "properties":{ "provider":"MVR", "code":"CRVI4", "slug":"crvi4", "elevation":645.0, "horizontal_datum":"", "vertical_datum":"NGVD29", "state":"IA", "kind":"PROJECT", "nearest_city":"Coralville", "public_name":"Coralville Lake Reservoir MET Station", "location_code":17017, "nsid":null, "aliases":{ "NIDID":"IA00012", "USGS Station Number":"05453510", "CWMS Legacy Naming":"CRVI4", "CWMS Standard Naming":"CRVI4" }, "timeseries":[ { "tsid":"CRVI4.Temp-Air.Inst.30Minutes.0.rev", "label":"Air Temperature", "base_parameter":"Temp", "parameter":"Temp-Air", "unit":"F", "unit_long_name":"Fahrenheit", "latest_time":"2026-05-20T14:00:00Z", "latest_value":51.52, "delta24h":null, "sort_order":22, "results":null }, { "tsid":"CRVI4.Flow-In.Inst.30Minutes.0.smoothed", "label":"Inflow", "base_parameter":"Flow", "parameter":"Flow-In", "unit":"cfs", "unit_long_name":"Cubic feet per second", "latest_time":"2026-05-20T11:00:00Z", "latest_value":3045.81, "delta24h":null, "sort_order":6, "results":null }, { "tsid":"CRVI4.Elev-Tail.Inst.30Minutes.0.rev", "label":"Elevation Tailwater", "base_parameter":"Elev", "parameter":"Elev-Tail", "unit":"ft", "unit_long_name":"Feet", "latest_time":"2026-05-20T14:00:00Z", "latest_value":651.56, "delta24h":null, "sort_order":3, "results":null }, { "tsid":"CRVI4.Elev-Pool.Inst.30Minutes.0.rev", "label":"Elevation", "base_parameter":"Elev", "parameter":"Elev-Pool", "unit":"ft", "unit_long_name":"Feet", "latest_time":"2026-05-20T14:00:00Z", "latest_value":684.07, "delta24h":null, "sort_order":1, "results":null }, { "tsid":"CRVI4.Stor.Inst.30Minutes.0.rev", "label":"Flood Storage", "base_parameter":"Stor", "parameter":"Stor", "unit":"ac-ft", "unit_long_name":"Acre-feet", "latest_time":"2026-05-20T14:00:00Z", "latest_value":29527.87, "delta24h":null, "sort_order":11, "results":null }, { "tsid":"CRVI4.Precip.Inst.30Minutes.0.rev", "label":"Precipitation", "base_parameter":"Precip", "parameter":"Precip", "unit":"in", "unit_long_name":"Inches", "latest_time":"2026-05-20T14:00:00Z", "latest_value":69.63, "delta24h":null, "sort_order":16, "results":null }, { "tsid":"CRVI4.Stor.Inst.30Minutes.0.rev", "label":"Conservation Storage", "base_parameter":"Stor", "parameter":"Stor", "unit":"ac-ft", "unit_long_name":"Acre-feet", "latest_time":"2026-05-20T14:00:00Z", "latest_value":29527.87, "delta24h":null, "sort_order":13, "results":null }, { "tsid":"CRVI4.Dir-Wind.Inst.30Minutes.0.rev", "label":"Wind Direction", "base_parameter":"Dir", "parameter":"Dir-Wind", "unit":"deg", "unit_long_name":"Degrees", "latest_time":"2026-05-20T14:00:00Z", "latest_value":338.0, "delta24h":null, "sort_order":23, "results":null }, { "tsid":"CTWI4.Flow.Inst.30Minutes.0.rev", "label":"Outflow", "base_parameter":"Flow", "parameter":"Flow", "unit":"cfs", "unit_long_name":"Cubic feet per second", "latest_time":"2026-05-20T14:00:00Z", "latest_value":3122.5, "delta24h":null, "sort_order":7, "results":null } ], "name":"Coralville Lake Reservoir MET Station", "hasResopsAverages":"true", "nidId":"IA00012", "nidid":"", "levels":[ { "slug":"elev.tempsl", "label":"TempSL", "parameter":"Elev-Pool", "base_parameter":"Elev", "tsid":"CRVI4.Elev-Pool.Const.0.TempSL", "latest_value":683, "units":"ft", "units_long_name":"Feet" }, { "slug":"elev.top of conservation", "label":"Top of Conservation", "parameter":"Elev-Pool", "base_parameter":"Elev", "tsid":"CRVI4.Elev-Pool.Const.0.Top of Conservation", "latest_value":683, "units":"ft", "units_long_name":"Feet" }, { "slug":"elev.top of exclusive flood control", "label":"Top of Exclusive Flood Control", "parameter":"Elev-Pool", "base_parameter":"Elev", "tsid":"CRVI4.Elev-Pool.Const.0.Top of Exclusive Flood Control", "latest_value":712, "units":"ft", "units_long_name":"Feet" }, { "slug":"elev.streambed", "label":"Streambed", "parameter":"Elev-Pool", "base_parameter":"Elev", "tsid":"CRVI4.Elev-Pool.Inst.0.Streambed", "latest_value":646, "units":"ft", "units_long_name":"Feet" }, { "slug":"elev.top of conservation", "label":"Top of Conservation", "parameter":"Elev-Pool", "base_parameter":"Elev", "tsid":"CRVI4.Elev-Pool.Inst.0.Top of Conservation", "latest_value":683, "units":"ft", "units_long_name":"Feet" }, { "slug":"elev.top of dam", "label":"Top of Dam", "parameter":"Elev-Pool", "base_parameter":"Elev", "tsid":"CRVI4.Elev-Pool.Inst.0.Top of Dam", "latest_value":743, "units":"ft", "units_long_name":"Feet" }, { "slug":"elev.top of flood", "label":"Top of Flood", "parameter":"Elev-Pool", "base_parameter":"Elev", "tsid":"CRVI4.Elev-Pool.Inst.0.Top of Flood", "latest_value":712, "units":"ft", "units_long_name":"Feet" }, { "slug":"stor.top of conservation", "label":"Top of Conservation", "parameter":"Stor", "base_parameter":"Stor", "tsid":"CRVI4.Stor.Inst.0.Top of Conservation", "latest_value":28070, "units":"ac-ft", "units_long_name":"Acre-feet" }, { "slug":"stor.top of flood", "label":"Top of Flood", "parameter":"Stor", "base_parameter":"Stor", "tsid":"CRVI4.Stor.Inst.0.Top of Flood", "latest_value":420960, "units":"ac-ft", "units_long_name":"Acre-feet" } ], "id":549868, "associatedStructuresCount":1, "conditionAssessDate":null, "conditionAssessDetail":null, "conditionAssessId":6, "damHeight":100, "damLength":1400, "distance":null, "drainageArea":3115, "eapId":1, "dsacAssignedDate":"2019-04-25T12:00:00.000Z", "eapMeetsGuidelinesId":1, "emergencyContactsUpdated":"2024-05-28T12:00:00.000Z", "eapLastRevDate":"2020-06-01T12:00:00.000Z", "enforcementAuthorityId":0, "federalId":"IA00012", "oldFederalId":"IA00012", "hazardId":4, "hydraulicHeight":93, "inspectionAuthorityId":0, "inspectionDate":"2023-12-06T12:00:00.000Z", "inspectionFrequency":1, "jurisdictionAuthorityId":0, "latitude":41.724478155, "lengthOfLocks":0, "secondaryLengthOfLocks":null, "longitude":-91.5297752069999, "maxDischarge":244000, "maxStorage":420960, "nidHeight":132, "nidStorage":420960, "normalStorage":28100, "numberOfLocks":0, "operationalStatusDate":"2019-04-25T12:00:00.000Z", "operationalStatusId":1, "originalDesignerName":null, "otherStructureId":null, "permittingAuthorityId":0, "politicalPartyId":null, "privateDamId":null, "projectDescription":"The U.S. Army Corps of Engineers (USACE) completed construction of Coralville Dam in June 1957 for the purpose of flood risk management, recreation, and fish and wildlife management. Coralville Dam is located on the Iowa River about 4 miles north of Iowa City, Iowa. The earthen dam is over about a quarter mile long with a maximum height of 96 feet. Water can be released from the lake in two ways. The first is through the gated outlet structure, which consists of a gate tower, a 23-feet-diameter reinforced concrete conduit, and a stilling basin, which helps slow down water as it is released from the lake. The second is through an emergency spillway located on the west side of the dam. The spillway structure consists of a concrete barrier wall with a concrete lined chute and side walls. The spillway allows water to flow over the top of the barrier wall during extremely high lake levels. The spillway structure transitions into a natural ground spillway that empties into the Iowa River approximately a quarter mile downstream of the dam. Coralville Dam has prevented over $700 million in flood damages and protects more than 23,000 people living and working in the area below the dam. The highest lake elevation observed was in 2008 and was just over 5 feet higher than the crest of the emergency spillway. Water has reached the spillway only two times, in 1993 and 2008. The 2008 event released the record amount of water through the dam at 39,500 cubic feet per second, approximately 16% of the design capacity.", "riskCharSummary":"USACE completed a risk assessment in May 2014 and classified the risk associated with Coralville Dam as low. Water released from the dam could impact densely populated sections of Iowa City and Coralville, Iowa, to include the University of Iowa, with little warning time in the extremely unlikely event of a dam failure. The dam was found to be well-designed, well-constructed, and well-maintained and is expected to be reliable during major floods. However, there is a very remote risk of dam failure from a failure of the spillway slabs and training walls leading to erosion of the dam embankment. Although highly unlikely, a dam failure would produce a devastating flood with flood depths greater than 15 feet through downtown Iowa City and Coralville. The flood would inundate portions of Iowa City and Coralville along the Iowa River and the small towns and rural communities downstream along the Iowa River. Approximately 23,000 people live or work within the worst-case inundation area of the flooding caused by a dam failure.", "riskManagementMeasures":"USACE works to reduce the risks posed to the community by Coralville Dam. The dam\u2019s Emergency Action Plan is updated regularly, and the emergency notification charts are updated annually. This plan has been coordinated with state and local Emergency Management Agencies to help improve their dam incident response planning and preparedness responsibilities. Emergency exercises are routinely held with local and state emergency responders and stakeholders to enhance the local communities\u2019 response plan and evacuation procedures. Dam breach flood maps are available for public viewing on the National Inventory of Dams. USACE is developing a detailed communication plan based on the latest risk assessment findings and will engage in communication activities with state and local representatives, stakeholders, emergency managers, and the general public to increase awareness. The dam has a robust instrumentation and monitoring program that allows USACE staff to regularly monitor the dam\u2019s performance under changing lake levels. USACE operations and engineering staff routinely conducts detailed inspections of the dam during both normal and high lake levels to ensure the integrity of the dam, identify deficiencies, and monitor known deficiencies. The dam is well maintained through continuous operations and regular maintenance activities. Lastly, the Iowa River Master Reservoir Regulation Manual, Water Control Manual for Coralville Lake is coordinated with upstream and downstream stakeholders, to allow the lake to be better managed in terms of earlier reservoir releases ahead of increasing lake levels in an effort to prevent emergency spillway releases.", "riverName":"IOWA RIVER", "separateStructuresCount":1, "sourceAgency":"US Army Corps of Engineers", "spillwayTypeId":3, "spillwayWidth":500, "stateFedId":"IA00012", "stateRegulatoryAgency":null, "stateRegulatedId":0, "structuralHeight":132, "submitDate":"2023-02-16T17:25:28.076Z", "surfaceArea":4050, "volume":1212835, "widthOfLocks":0, "secondaryWidthOfLocks":null, "yearCompleted":1958, "congDist":"Congressional District 01, Iowa", "city":"IOWA CITY", "county":"Johnson", "aiannh":null, "websiteUrl":"https://www.usace.army.mil/Missions/Civil-Works/Dam-Safety-Program/Article/2870967/dam-safety-program/", "coreTypeIds":"3", "damTypeIds":"9;8", "fedConstructionIds":"1", "fedDesignIds":"1", "fedFundingIds":"1", "fedInspectionIds":"1", "fedOperationIds":"1", "fedOtherIds":"1", "fedOwnerIds":"1", "fedRegulatoryIds":"1", "formerNames":null, "foundationTypeIds":"1;3", "nonFederalDamOnFederalId":0, "designerNames":"CEMVR", "otherNames":"Coralville Lake", "ownerNames":"USACE - Rock Island District", "ownerTypeIds":"3", "primaryDamTypeId":9, "primaryOwnerTypeId":3, "primaryPurposeId":9, "purposeIds":"9;5", "dsacId":4, "femaRegion":"7", "lastEapExcerDate":"2021-10-05T12:00:00.000Z", "dataUpdated":"2025-05-21T12:00:00.000Z", "usaceDistrict":"Rock Island District", "noConsequencesId":0, "secretaryAgricultureBuiltId":null, "nrcsWatershedAuthorizationId":null, "isAssociatedStructureId":"No", "fedRegulatedId":"Yes", "inundationNidAddedId":1, "damStatusId":2, "huc06":"070802", "doi_region":null, "doi_region_name":"Mississippi Basin", "doi_region_number":4, "thirtyYearAverage":99.1784, "tenthPercentile":32.2848, "ninetiethPercentile":234.2898 }, "id":17017, "links":[ { "type":"application/json", "rel":"root", "title":"The landing page of this server as JSON", "href":"https://arizonawaterobservatory-api.rtd.asu.edu?f=json" }, { "type":"text/html", "rel":"root", "title":"The landing page of this server as HTML", "href":"https://arizonawaterobservatory-api.rtd.asu.edu?f=html" }, { "rel":"self", "type":"application/geo+json", "title":"This document as JSON", "href":"https://arizonawaterobservatory-api.rtd.asu.edu/collections/usace-edr/items/17017?f=json" }, { "rel":"alternate", "type":"application/ld+json", "title":"This document as RDF (JSON-LD)", "href":"https://arizonawaterobservatory-api.rtd.asu.edu/collections/usace-edr/items/17017?f=jsonld" }, { "rel":"alternate", "type":"text/html", "title":"This document as HTML", "href":"https://arizonawaterobservatory-api.rtd.asu.edu/collections/usace-edr/items/17017?f=html" }, { "rel":"collection", "type":"application/json", "title":"USACE Access2Water API", "href":"https://arizonawaterobservatory-api.rtd.asu.edu/collections/usace-edr" } ] }