Stormwater Capital Program

What is a Watershed?

Do you live in a watershed? The answer is “yes” - everyone does. A watershed is an area of land where rainwater flows into a common body of water such as a stream, creek, river, lake or ocean. A watershed can be as small as a backyard or many thousands of square miles. For example, a small watershed like your neighborhood can be part of a larger watershed like the Trinity River Watershed which encompasses 18,000 square miles and includes all or parts of 38 Texas counties. The Mississippi River Watershed drains to the Gulf of Mexico, just like the Trinity River, but is comprised of 1.5 million square miles!

Within the City of Arlington, most property drains to creeks. The City of Arlington has 10 major watersheds which can be broken into smaller watersheds for the various creek tributaries. The creeks within each watershed have an associated 100-year floodplain. The 100-year floodplain is the area that has a 1% chance of flooding within any given year. The 100-year floodplain is the area that is regulated by the City and FEMA. The City participates in the National Flood Insurance Program (NFIP) which underwrites flood insurance based upon a properties flood risk. While all properties are within a watershed, not all properties are located within the 100-year floodplain. The City can help you determine if you are in the floodplain.

Why study the watersheds?

There are several reasons to study the watersheds:

Accurate and credible flood risk data - Some of the data used in the current FEMA floodplain maps has not been updated since the 1970s. Land development has significantly changed the quantity of water within its creeks and the way that the water flows within its watersheds. The watershed studies will update this information so that floodplain mapping is more accurate.

Updated FEMA Maps - Once the studies are complete and the floodplain is remapped, the data will be submitted to FEMA. FEMA will update its current Flood Insurance Rate Maps (FIRM) which are used to determine which properties need flood insurance and what the flood insurance rates should be.

Better project planning - The City has an extensive database of flooding concerns. However, many properties that experience flooding do not report the flooding to the city. The watershed studies will identify areas of flood risk to coordinate with the reported flooding concerns which provides a more comprehensive flood mitigation program.

Risk identification to protect development - When new development occurs, information within the studies will be used to make sure that the new development is protected while also ensuring that it is not impacting flooding on adjacent property.

Channel stability assessment - The creeks are also evaluated for their condition with respect to erosion. This allows the city to protect its infrastructure - waterlines, sewer lines, bridges, roads, etc. - and provides a catalog of current creek conditions.

What steps are included in a watershed study?

The City retains professional engineering firms to perform its watershed studies. These firms or teams of firms take the following steps when studying a watershed:

Information Gathering - The first step is to know what information already exists for the watershed. Items such as current floodplain maps and computer models, maps of the storm drain system, construction plans, and floodplain map changes are important as a base to the study. Public meetings also occur during this time to gather information from residents impacted by the creek.

Survey - Professional land surveyors will perform field survey of the creeks within the watershed. Homeowners in the area of the survey will receive a letter notifying them of the survey. A combination of field survey and topographical maps will be used to create watershed boundaries and creek cross sections.

Hydrology - Hydrology is the term used for determining how much water is generated by the watershed. This is based on the land area, the impervious area within the area and the flow path of the water. A computer model is used to take these factors and determine the quantity of water at points along the creek for various storm events - 5-year event, 25-year event, 100-year event, etc.

Hydraulics - Hydraulics is the term used for determining how the water flows through the creeks. A computer model will be used to determine the water surface elevations and velocities along the creek for various storm events.

Mapping - Once the hydrology and hydraulics are complete, the new floodplain area will be mapped. The hydrologic and hydraulic model results will be forwarded to FEMA for incorporation into their Flood Insurance Rate Maps (FIRM).

Problem Area Identification and Project Identification - Once the maps are complete, properties at risk for flooding will be identified. These will also be cross-referenced with our historic drainage concerns and potential drainage projects will be identified. These projects are prioritized and programmed into the stormwater capital budget. The City Council approves the capital budget each spring.

What is the status of the current watershed studies?

Studies of 6 of the 10 watersheds within the City of Arlington are either complete or underway.

Fish Creek and Cottonwood Creek - These were our first studies and were a part of a FEMA grant and partnership with the City of Grand Prairie. The City has completed these studies and they are currently in the 90-day appeals process with FEMA. Seven flood mitigation projects were identified through this study. Two of the projects - Sherry Street Culvert at Tributary CC-3 and Susan Drive Culvert at Cottonwood Creek - are under construction. These two projects were coordinated with other projects which allowed them to be expedited and to be less expensive since they were part of larger projects. A third project - Cottonwood Creek at Park Row - is in design right now.

Rush Creek - In 2010, Tropical Storm Hermine hit the Rush Creek watershed particularly hard. Extensive flooding within the watershed highlighted risks to structures and infrastructure within the watershed and led to it being the first comprehensive study performed exclusively with stormwater utility funds. This study is nearing completion and submittal to FEMA is anticipated in early 2016. Ten flood mitigation projects were identified. Two of the projects - Sublett Creek Neighborhood Drainage Improvements and Country Club Road Local Drainage and Channel Improvements (south of Park Row) - are currently in the design phase.

Johnson Creek - Johnson Creek has historically been Arlington's most talked-about creek. Historic problems in this watershed have led to the buyout of many homes and plans for linear parks along it. While many of the problems have been addressed, there are still many to go. This study is also nearing completion and submittal to FEMA is anticipated by the end of the year. Project identification is in progress. Currently 19 projects have been identified. These projects are currently being verified and ranked.

Trinity Tributaries and Lower Village Creek - This is the newest study and includes all of Lower Village Creek and the major tributaries to the Trinity River. This study was started in July 2015 and data gathering and survey are underway. A series of three public meetings has been held to gather information from residents within the watershed. Completion is anticipated in 2017.

What studies are still needed?

Upper Village Creek and Remaining Trinity Tributaries - Proposed to start in 2017

Lynn Creek, Bowman Branch and Walnut Creek - Proposed to start in 2018 and will include stream assessment for Fish and Cottonwood Creeks.

How are watershed studies funded?

The City's stormwater program is funded through the Stormwater Utility Fee that is included with the water bill. Currently, the Stormwater Utility Fee is $5.25 per residential lot and based on the amount of impervious area (parking lots, buildings, driveways, etc.) for commercial property. The fee supports all aspects of the stormwater program including: watershed studies, flood mitigation projects, a stormwater field crew, environmental compliance, environmental education, and engineering and administration staff.

How can I find out more information?

You may contact the Department of Public Works and Transportation at 817-459-6550 and ask to speak with a stormwater engineer. The stormwater engineers can talk to you about drainage problems you are having, floodplain questions or other stormwater-related issues.

• Map of Major Arlington Watersheds(PDF, 238KB)
• Rush Creek Watershed Study(PDF, 238KB)
• Rush Creek Watershed Study Area Map(PDF, 5MB)

The Municipal Separate Storm Sewer System (MS4) is more commonly known as the storm drainage system. The storm drainage system collects excess rainwater (stormwater) and discharges it into our local creeks, streams, rivers and lakes. This system of inlets, pipes, channels, flumes, culverts and other components helps reduce flooding by moving excess water off roadways and away from homes, schools and businesses. The storm drainage system provides an essential service to our community. However, it is important to understand that the storm drainage system is not the same as the sanitary sewer system. The sanitary sewer system collects wastewater from kitchens and bathrooms using a series of underground pipes. It is then discharged to a sewage treatment facility where the wastewater is filtered, treated and then discharged. Stormwater is not treated prior to discharging into our natural waterways therefore anything left on the ground or in the street has the potential to become a stormwater pollutant.

Here are some things you can do to help maintain our storm drain system and keep our local waterways clean:

• Do not pour any chemicals into the storm drainage system. Paints, automotive fluids, household cleaners need to be taken to the local household hazardous waste collection center.
• Keep yard wastes like leaves, grass clipping, tree limbs or sticks out of the storm drain.
• Repair any vehicle leaks or drips immediately.
• Collect and recycle motor oil.
• Clean up spills and don’t wash them into a storm drain.
• Maintain swimming pools and septic tanks properly.
• Reduce your use of pesticides and fertilizers. Always use lawn chemicals in accordance with the manufacturer’s recommendations. Never use chemicals on your lawn when it is going to rain.
• Always pick up after your pet.

Visit the Stormwater Educationpage to learn more about Stormwater Pollution and Prevention.

Fill out the online flooding questionnaire.

Please contact the Public Works Department at 817-459-6550 or submit an Ask Arlington concern. A Stormwater Engineer will evaluate your concern and determine if it is a drainage project candidate. We recommend flood insurance to all property owners or renters in Arlington. Flood insurance is available to everyone in Arlington. Please see the Flood Insurance Program page for more information.

Ensure your lot is properly graded so that water runs away from your buildings and towards a street or storm drainage system. If an area of your yard is experiencing erosion due to concentrated runoff, plant grass or other vegetation with roots that will hold the soil in place. Occasionally, private area drains and underground pipes may be necessary. We recommend they are designed by a civil engineer or landscape contractor experienced in drainage problems so that the they are properly sized and sloped. Drains should be placed in low points away from any buildings and must be maintained regularly. Perforated pipes surrounded by rock or “french drains” should not be used unless you are addressing an issue with groundwater rather than surface runoff. A stormwater engineer may be able to visit your property and offer advice on how you can reduce your flooding risk depending on the current workload. To request a site visit or an evaluation of a proposed plan for a private drainage system, please contact the Public Works Department at 817-459-6550 or submit an Ask Arlington concern.

These situations are civil matters between property owners. It does not violate city code for one lot to drain onto another. You should meet with your neighbor and discuss the problem to work toward a mutually agreeable and beneficial solution. Diverting or concentrating the natural flow of water violates Texas Water Law. City code covers new construction that meets permitting thresholds, but unpermitted improvements or existing drainage that violates Texas Water Law can only be enforced through civil court action.

If the area drained onto the adjacent property prior to development, it may continue to do so after development. New development may not worsen existing flooding as reported to the City. If problems are being created during construction, contact the Planning and Development Services at 817-459-6502.

The developer of a subdivision or a commercial site is required to maintain stormwater pollution prevention controls on his property until adequate vegetation is established. Contact the Public Works Department at 817-459-6550 and ask to speak with the Environmental Division or submit a stormwater pollution Ask Arlington concern.

If the pool is draining onto private property then it is a civil matter between property owners. However, it is a violation of city code to drain chlorinated pool water into the street or to flood adjacent property. If you are concerned that City code is being violated, contact the Public Works Department at 817-459-6550 and ask for the Environmental Division.

The City of Arlington will remove large debris that may increase the risk of flooding or change the natural course of water within a stream. Downed trees or other large obstructions should be reported to the City. Property owners are otherwise responsible for maintaining the stream on their property. Vegetation is the best natural defense against stream erosion. Make sure to plant non-invasive, native plants. Stream erosion is often a combination of erosion from streamflow and erosion caused by runoff going into the stream. Reduce concentrated points of runoff into your stream and ensure there is a 5-10’ unmoved vegetated buffer at the top of your streambank. Do not dump yard or construction debris onto the streambank as this can cause further erosion within the stream and can cause debris jams that may result in flooding. Yard debris or other hazardous materials can also be highly detrimental to aquatic life within streams. If you are experiencing severe stream erosion, it may be necessary to hire a professional engineer to design improvements. Walls or other improvements in streams may require City permits, federal permits, flood studies, and/or FEMA map changes.

While some debris is naturally occurring, like leaves or branches, an oversupply of yard debris or other materials such as tires, plastic, or construction debris are detrimental to the stream ecosystem and aquatic life. Refrain from storing potential debris, including scrap lumber, firewood, leaf piles, or hazardous materials in streambank areas where it may be washed into the stream. Disposing of yard waste in your stream is strictly prohibited by law for several reasons. Piled grass clippings kill off underlying vegetation that could otherwise help stabilize the stream bank. When these nutrient-rich clippings enter the water, they can cause algae growth, odor issues, and reduce the amount of oxygen in the water, killing fish and other aquatic organisms. Debris jams often resulting in localized flooding and erosion of streambanks. If yard waste is disposed of illegally on a stream bank, the landowner will be asked to remove the debris and may be subject to a fine.

If your street is public, we will place your location on a list and it will be surveyed and given a rating based on the severity of the ponding. If the problem is fairly minor, it will be placed on a list to be repaired by the Public Works and Transportation Department’s Street Division. If it is more significant, it may be placed on a list for a future street rebuild project. If you live in a private subdivision, then it is the responsibility of the homeowner’s association or the individual homeowner to correct the problem.

The Stormwater Management Division will inspect for blockages and remove debris if present. If it appears there is a capacity issue, then it may become a candidate for a drainage improvement project. If the system is private, then it is the responsibility of the homeowner’s association or the individual homeowner to maintain the system.

Fences are allowed in drainage easements in some situations. A fence permit and Easement Use Agreement must be obtained from the Planning and Development Services for any fence construction within an easement. Any fences placed in an easement without an Easement Use Agreement are subject to removal by the City. Fences are never allowed across concrete channels, within natural creeks, or within the floodway.

Public drainage systems are located within public drainage easements or street right-of-way, and are the city’s maintenance responsibility. Private drainage systems are located on private property and may or may not be located within drainage easements. Private drainage systems are required to be maintained by the property owner or homeowner’s association.

If a drainage problem is caused by public infrastructure (or lack of necessary infrastructure) then the City may designate the problem as a project candidate. Each year project candidates are listed and ranked based on specific criteria including number of residences that flood, frequency of flooding, and cost effectiveness of the project. After the projects are ranked, they are placed on the Stormwater Program. The Stormwater Program is a multi-year plan that identifies drainage projects proposed for upcoming years. Project priorities can change from year to year as new problem areas are identified. The number of drainage projects planned for a given year is based on the project costs as related to the revenues generated by the Stormwater Utility Fee. If you have any questions about a project on the list, contact the Department of Public Works and Transportation at 817-459-6550.

Please contact the Department of Public Works at 817-459-6550 and ask to speak with a Stormwater Engineer. We can send someone out to evaluate whether the water is groundwater, tap water, or sanitary sewer water. If it is groundwater, then it is the property owner’s responsibility to address the problem. You may wish to contact a civil engineer or landscape contractor experienced in drainage problems.

Please contact the Department of Public Works at 817-459-6550. If the system is public, we can investigate the cause of the problem and repair the system if necessary. If the system is private, then the owner of the system is responsible for maintenance.

Please contact the Department of Public Works at 817-459-6550. The City has a program to inspect and clean concrete channels. A work order will be issued, and they will call you to discuss the problem. Workloads and other priorities will determine when the channel will be cleaned. You are responsible for maintaining the area between your fence line and the top of the concrete channel.

City crews will clean and regrade ditches as needed, but homeowners are responsible for cleaning out driveway culverts.

Contact the Department of Public Works at 817-459-6550 and ask to speak with a Stormwater Engineer or submit and Ask Arlington concern. Once any questions have been answered or action has been taken, the engineer will log the complaint into a database for future tracking.