Dam Report

Lewisville Dam dam

Texas, USA Elm Fork Of The Trinity River Hazard High
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Tonight low
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Dam height
130ft
Hazard rating
High
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Lewisville Dam -- None dam
Lewisville Dam None · Elm Fork Of The Trinity River
About this dam

Lewisville Dam

Lewisville Dam, located in Denton, Texas, along the Elm Fork of the Trinity River, serves as a crucial flood risk reduction infrastructure designed by the US Army Corps of Engineers. Completed in 1955, the dam stands at 130 feet high and spans 32,328 feet in length, with a primary purpose of flood risk reduction. Despite its effectiveness in reducing downstream flooding, a risk assessment conducted in October 2014 identified the dam as having a high hazard potential, particularly during extreme flood events that could lead to a breach or large flows over the spillway, impacting communities downstream such as Lewisville, Coppell, Carrollton, Farmers Branch, Irving, and Dallas.

To address the identified deficiencies and reduce the risk associated with the dam, the US Army Corps of Engineers has implemented various risk management measures. These include working closely with local emergency managers to develop evacuation plans, regularly updating the emergency action plan, conducting emergency exercises, and ongoing inspections and maintenance of the dam. Furthermore, construction is underway for dam safety modifications, such as building a downstream inverted filter berm, anchoring the spillway weir, and constructing a barrier wall downstream of the spillway to enhance the dam's structural integrity and reduce the risk of failure. Despite the remote probability of failure, efforts are ongoing to safeguard the dam and surrounding communities from potential catastrophic impacts.

StateNone
River / streamElm Fork Of The Trinity River
NID IDTX00008
Owner typeFederal
Primary purposeFlood Risk Reduction
Dam typeEarth
Year built1955
Dam height130 ft
Dam length32,328 ft
Max storage1,804,300 AF
Normal storage618,400 AF
Surface area23,280.0 ac
Drainage area1,660.0 sq mi
Hazard potentialHigh
ConditionNot Available
Last inspectionFri, 08 Mar 2019 06:00:00 GMT
EAP preparedYes

Dam data reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action.
Poor
A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environmental damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Detailed forecast

Plan around the weather

Same NOAA / yr.no feed Snoflo's iOS app uses. Watch the precipitation column on the meteogram -- rain on the basin upstream typically lifts inflow 24-72 hours later.

Hourly detail

Next 5 days, hour by hour

Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.

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Deep dive

5-day forecast table

Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.

TimeConditionTemp (°F)Snow (in)Rain (in)Humidity (%)Wind (mps)Wind dir
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Long-term outlook

15-day temperature & precipitation

Daily temperatures, snow, and rain projected over the next two weeks.

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Regional inflow

Nearby streamflow gauges

USGS streamgauges around Lewisville Dam -- inflows here typically show up in storage 24-72 hours later.

Track Lewisville Dam in the Snoflo app

Save this dam as a favorite and get the local NOAA / yr.no forecast plus regional flow context wherever you are.

FAQ

About Lewisville Dam

Where does the data for Lewisville Dam come from?

Structural and regulatory data come from the U.S. Army Corps of Engineers' National Inventory of Dams (NID). Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.

How often is the report updated?

NID structural data refreshes annually as the Corps publishes updated assessments. The weather forecast refreshes throughout the day.

What does the High hazard rating mean?

The Corps of Engineers' hazard potential classification grades probable consequences if the dam fails: High = probable loss of human life; Significant = no probable loss of human life but possible economic loss / environmental damage; Low = no probable loss of human life, only minor economic / environmental losses. See the Dam Data Reference card above for the full definitions.

What's "% of normal"?

The current storage value compared to the historical average storage on this calendar day. 100% = right on average; values above 100% mean above-normal storage (wet year); values below mean below-normal (dry year or drought).

Can I get alerts when storage crosses a threshold?

Yes -- alerts are managed in the Snoflo iOS app. Favorite this dam, set a threshold, and you'll get a push the moment conditions cross.