ENGINEERING :: FLOODPLAIN / ELEVATION

Flood Awareness and Protection

Every year, flooding causes hundreds of millions of dollars worth of damage to homes and businesses around the country. Standard homeowner and commercial property insurance policies do not cover flood losses. So, to meet the need for this vital coverage, the Federal Emergency Management Agency (FEMA) administers the National Flood Insurance Program (NFIP). The NFIP’s Community Rating System (CRS) recognizes community efforts beyond minimum standards by reducing flood insurance premiums for the community’s property owners.

The City of Arlington’s CRS Rating of 8 provides property owners a 10% discount on flood insurance premiums. The following information is intended to inform you of flood hazards in the City of Arlington and to present ways your property can be protected against flood damage.

Flood Hazard Area

The vast majority of these creeks, streams, or tributaries are primarily located in the city of Arlington; thus flows from surrounding communities have minimal impact on the city of Arlington. Eight major drainage basins (watersheds) are identified in the city limits of Arlington, TX include Johnson Creek, Rush Creek, Cottonwood Creek, Fish Creek, Lynn Creek, Bowman Branch, Village Creek, the West Fork of the Trinity River as well as various smaller creeks, streams, and tributaries. Due to the continued increase in urban development throughout the City of Arlington, flood risks to life and property have increased.

Floodplains are the area where there is a 1-percent chance annually that a flood will equal or exceed this limit. This is typically referred to as the 100 year floodplain. For reference, if a structure is located in the 1-percent chance flood zone, over the life of a 30-year mortgage there is a 26% chance that the structure will be flooded at least once.

The 1-percent chance floodplain area is subject to dangerous flash flooding following heavy storms. Flash flooding can occur within minutes. Therefore, being prepared to evacuate the flood hazard area quickly is very important. Flood hazards include quickly rising and fast moving water, which is sometimes accompanied by debris.

Map Determination

The City’s Geographic Information System (GIS) has the following Flood Insurance Rate Map (FIRM) information:

• The parcels located in an identified special flood hazard area.
• The community number, panel number and suffix.
• The date of the FIRM and the FIRM zone.
• The base flood elevation shown on the FIRM and the elevation datum used on the FIRM.

The City of Arlington’s Department of Public Works and Transportation also maintains information that can provide the Best Available Information about flood risk in addition to the FEMA Flood Insurance Rate Map information. If you have questions about your location in relation to the floodplain, you can find your property on the FEMA Flood Insurance Rate Map by clicking here or you can contact the City of Arlington’s Department of Public Works and Engineering at 817-459-6550 for assistance or to request a flood determination.

Flood Warning System

The National Weather Service has developed a flood warning system for areas in the Upper Trinity River system. A warning will be disseminated by radio stations including KRLD 1080AM, WBAP 820 AM, KLIF 570 AM and others. The National Weather Service issues official weather bulletins to local and regional television stations including KDFW (FOX), KTVT (CBS), KXAS (NBC), WFAA (ABC), KDAF (WB), and KXTX (Independent).

The National Weather Service has hourly precipitation data available at the following link: http://www.srh.noaa.gov/rfcshare/precip_analysis_hourly.php.

The U.S. Geological Survey also has stream gauge data available for Lake Arlington at the following link: http://waterdata.usgs.gov/nwis/uv?08049200

When an evacuation is ordered, local television and radio stations broadcast the order. A flash flood watch means flash flooding is possible within the watch area. A flash flood warning means flash flooding is imminent or has been reported in the warning area.

You can obtain additional information about evacuation, shelters and emergency procedures by calling 911, the Fire Department at 817-459-5500 or the Police Department at 817-459-5700.

Flood Safety

During a flood, gas, water and power lines can be ruptured. Before leaving your property, turn off electric circuits and shut off gas and water valves. These simple steps can prevent additional losses due to fire, and the following actions can help to mitigate the flood hazard during heavy rainfall:

• Monitor the level of water in streams and stay tuned to the radio or television for possible flood waters or warnings.
   
• Evacuate the flood hazard area in times of impending flood or when advised to do so by the police or fire department.
   
• Do not walk through flowing water. Drowning is the number one cause of flood deaths. Currents can be deceptive; six inches of moving water can knock you off your feet. If you walk in standing water, use a pole or stick to ensure that the ground is still there.
   
• Do not drive through a flooded area. More people drown in their cars than anywhere else. Do not drive around road barriers; the road or bridge may be washed out.
  "TURN AROUND… DON’T DROWN!"
   
• Stay away from power lines and electrical wires. The number two flood killer after drowning is electrocution. Electrical current can travel through water. Report downed power lines to 911 and ONCOR Electric at 1-888-313-4747.
   
• Be alert for gas leaks. Use a flashlight to inspect for damage. Don’t smoke or use candles, lanterns, or open flames unless you know the gas has been turned off and the area has been ventilated.
   
• Look out for animals, especially snakes. Small animals that have been flooded out their homes may seek shelter in your home. Use a pole or stick to poke and turn things over and scare away small animals.
   
• Keep children away from floodwaters, ditches, culverts and storm drains, and be especially cautious at night.

Flood Insurance

Your homeowner’s insurance policy will not cover losses due to flooding. The City of Arlington participates in the National Flood Insurance Program, which makes flood insurance available to all city residents. If you don’t have flood insurance, talk to your insurance agent. This insurance is backed by the Federal government and is available to everyone, even for properties that have been flooded.

Don’t wait for the next flood to buy insurance protection. There is a 30-day waiting period before National Flood Insurance Program coverage takes effect. Contact your insurance agent for more information on rates and coverage.

Some people have purchased flood insurance because it was required by the bank when the received their mortgage or home improvement loan. Usually these standard flood insurance policies only cover the building’s structure and not the contents. During typical flood events in Arlington, there is usually more damage to the furniture and contents than there is to the structure.

As of October 2009 there were 1,537 flood insurance policies in the City of Arlington. If you are covered, double-check that the building coverage is adequate and make sure you have contents coverage. REMEMBER: Even if the last flood missed your property or you have done some flood proofing, the next flood could be worse. Flood insurance covers all surface floods.

For general program information or inquiries about the laws, regulation or administrative policies related to NFIP, visit FEMA’s web site or call them at 1-800-427-4661.

Property Protection

There are steps that can be taken to flood-proof structures. Some of these include:

• Elevate the structure so floodwaters do not reach any damageable portion of the structure.
   
• Construct barriers between the structure and floodwaters.
   
• Make structural walls and floors watertight so water does not enter (dry flood-proofing). Modify the structure and relocate the contents so there is little or no damage when floodwaters enter the building. Prevent sewer backups and basement flooding by installing a one-way check valve in the sewer line.
   
• Elevate electrical panel boxes, furnaces, air conditioning equipment, water heaters and laundry equipment.

There are also special flood-proofing techniques used in unusual flooding situations, including elevation on fill and elevation on reinforced mat slabs. For more information on Floodproofing, visit FEMA’s Floodproofing web page.

Floodplain Development Regulations

The City of Arlington has adopted regulations and permit procedures to control development in or adjacent to the Special Flood Hazard Areas. The regulations require new buildings to be elevated a minimum of 2 feet above the base flood elevation. If additions or remodeling to an existing structure located in a special flood hazard area equal or exceed 25% of the market value of the structure, the structure must meet the same requirements as a new building. If an existing structure located in a special flood hazard area is damaged and repairs equal or exceed 50% of the market value of the structure, the structure must meet the same requirements as a new building.

Other additions, remodeling, repair, filling or excavating on the property require a permit which must be applied for at the City’s Community Development and Planning Department One Start permit center prior to beginning any construction. For construction activities associated with structures in or adjacent to the floodplain, the City of Arlington requires an Elevation Certificate be completed and filed with the City upon the completion of construction. All Elevation Certificates filed with the City of Arlington are available to the public for review in determining flood risk.

If you know of construction, filling or excavation that is taking place without a City Permit, please report the activity to the City’s Community Development and Planning Department at 817-459-6652. If you know of any action that is affecting the City’s drainage systems and is being done without a permit, please contact the Public Works & Transportation Department at 817-459-6550.

Natural and Beneficial Functions

Local and regional floodplains play a valuable role in providing natural and beneficial functions that benefit to both human and natural systems. These include aesthetic as well as active processes such as filtering nutrients. The Upper Trinity River’s tributary floodplains are used as a means to filter municipal run-off. It is the riparian areas associated with these floodplains that act as a filter and assist in filtering storm and floodwaters so as to maintain bio-diversity and ecosystem sustainability. These floodplains also contain historic and archeological sites that provide opportunity for education and study. Floodplains include areas for waterfowl, fish, and other wildlife habitats in addition to feeding and breeding grounds. When flooding spreads out across the floodplain, its energy is dissipated, which results in lower flood flows downstream, reduced erosion of the streambank and channel, and deposition of sediments higher in the watershed. Poorly planned development in the floodplain can lead to streambank erosion, loss of valuable property, increased risk of flooding to downstream properties and degradation of water quality.

Maintenance of Drainage Systems

The City’s Public Works & Transportation Department maintains the storm drainage system throughout the City. For the drainage system to operate efficiently, ditches, streams and channels must be kept clean. Debris, leaves, grass clippings, tires or furniture in ditches and streams obstruct the flow of water, cause flooding of streets and yards, and degrade water quality.

The City’s Stormwater Ordinance and State Regulations prohibits dumping of any material in a stream or channel and also makes it illegal to take any action which will impede the flow of water in natural streams and waterways. If you know of or are aware of illegal dumping or prohibited activities, please report the activity to Public Works & Transportation Department at 817-459-6550. Before making any changes to existing drainage of your property, please discuss your plans with a representative of the City’s Community Development and Planning Department.

Frequently Asked Questions

What is a 100-year floodplain?
It is the area of land inundated by floodwaters from a storm that has a one percent (1%) probability of being equal at or exceeded in any given year.

What is the difference between FEMA designated zones A, AE, and X?
Zone A is an area of the 100-year floodplain that has not been studied in sufficient detail to determine the water surface elevation of the 100-year flood. Zone AE is the area of the 100-year floodplain with the elevation of the 100-year flood available and the floodway designated. Zone X is an area inundated by the 500-year storm or areas outside of land inundated by the 500-year storm.

Who do I need to speak with to construct something in a floodplain?
Please contact the City's Department of Public Works receptionist at 817-459-6550 and she will forward your inquiry to the appropriate staff person.

What is the floodway?
The area of the channel of a creek and the adjacent land areas that are reserved for flood flows. This area is to be clear of fences, buildings, fill, or any other obstructions that could inhibit flood flows.

How do I get an elevation certificate?
The City can provide you with a copy of an existing elevation certificate on file. However, if there is no elevation certificate on file then you will have to contact an engineer or surveyor of your choice to obtain an elevation certificate.

I have never been in a floodplain before and my property has never flooded but now my mortgage company and/or insurance provider is wanting me to secure flood insurance because my house is now designated in the floodplain.
Usually this is caused by a refinance, replat, or add-on construction requiring a building permit.  This can also be caused by updated FEMA flood maps.  One solution to this issue is to secure an Elevation Certificate.  If the Elevation Certificate states that your slab is high enough above the floodplain, you may satisfy your mortgage lender or qualify for reduced insurance rates.

I have specific floodplain questions concerning my Arlington property.  Who do I contact to have my questions answered?
Please contact the Department of Public Works at 817-459-6550.

Where can I find information and answers to general floodplain questions on protecting my home from flooding?
Please visit the Federal Emergency Management Agency's (FEMA) website at www.fema.gov .

[ back ]