Benefits Provided by Dams

Dams provide benefits to residents and businesses by mitigating flood impacts by containing stormwater, and reducing flood insurance premiums. Downstream areas of these dams are considered a minimal flood risk zone by the Federal Emergency Management Agency (FEMA). Dam failures are vary rare but can occur from different causes.

Most Common Reasons for Dam Failures

Overtopping

Failure from overtopping can occur when water flows over the top of an earthen embankment, resulting in erosion of the embankment. This is most often the result of inadequate spillway capacity, debris blockage, or embankment settlement.

Piping

Seepage occurs naturally on most dams, but defects can occur when earthen materials internally erode and progress to form voids in the dam.

Embankment Defects

Common embankment defects than can lead to a dam failure include excessive settlement, slope slides and instabilities, and cracking.

Inadequate Maintenance

Common maintenance issues include vegetation maintenance, repair of concrete structures, maintaining spillway capacity, and instrumentation monitoring

City of Dallas Dam Safety Protocol

Minimizing the Risk of Dam Failures

The City of Dallas maintains dams at the highest standards to increase safety and minimize the risk of dam failures by meeting state dam safety laws and regulations as required by the Texas Commission on Environmental Quality.

Below highlights some of the activities Dallas Water Utilities and Dallas Park & Recreation conduct to maintain safety standards.

Regular inspection and monitoring programs

• Performs maintenance inspections on dams quarterly and after large rainfall events
• Annual inspections by City engineers
• Engineering consultants with dam safety expertise are contracted every 5 years to perform detailed engineering inspections

Regular maintenance program

• Vegetation Control Rock Riprap Maintenance and Repair
• Mechanical Maintenance
• Cleaning and Debris Removal
• Pedestrian and Traffic Control
• Animal/Rodent/Fire Ant Control

Maintaining Emergency Action Plans (EAPs)

• Practice emergency preparedness with the City of Dallas Office of Emergency Management, Dallas Fire Department, Dallas Police Department, National Weather Service and TCEQ
• Update Emergency Notification Call list quarterly

Detailed reviews and analyses

• Flood studies
• Stability analyses
• Potential Failure Mode Analyses (PFMA)

Residential Safety Measures

Residents and businesses located near a dam and/or in the downstream areas of a dam should take the following actions to decrease risks.

• Sign up for emergency notifications through the DallasAlert program.
• Create an action plan with a checklist of important items and their locations
• Keep valuable information and items easily accessible on high tables or shelves and never on the floor or lower shelves

Residents and Businesses Should Consider Flood Insurance

Residing near dams is a potential risk; however, the City of Dallas encourages residents and businesses to consult with their insurance provider on whether they need flood insurance to protect themselves and their property.

Flood Insurance

Dallas residents benefit from the City's participation in the National Flood Insurance (NFIP) and the Community Rating System (CRS) to provide property owners with an opportunity to purchase flood insurance at a lower premium rate. The City of Dallas encourages residents to speak with their insurance provider for more details to prepare for unlikely flooding events.

Steps to Take if there is a Flood

• Beware of bad weather conditions
• Do not drive through a flooded area: "Turn around, don't drown!"
• Listen to emergency notifications
• Stay away from power lines and electrical wires
• Do not walk through flowing water
• Evacuate if needed