Storm Water Management

Slow, Soak and Release

These words are the key components of any storm water management technique. Slow down the velocity of runoff, soak up the volume of runoff and release what is not soaked in, slowly and pollutant free.

The state of Oklahoma receives an average annual precipitation of 36 inches. The precipitation that is not infiltrated as part of the natural hydrological is considered runoff. A natural, undeveloped area allows for about 18 inches per hour of infiltration, where an average lawn allows for about 2 inches per hour. Impervious surfaces like pavement and rooftops, offer no infiltration at all. 

Stormwater is the water coming off roofs from your home, garage, and down your driveway. If a home has 2,000 square feet of impervious surfaces, that is equal to 1,246 gallons of stormwater runoff. That’s a lot of water that needs somewhere to go! When our drainage system is overwhelmed by excessive rainfall, water can back up and cause localized flooding.


When water is no longer filtered by trees and soil, it quickly accumulates on paved surfaces and either causes flooding or runoff.  This runoff can pick up debris, chemicals, bacteria, sediment, and other pollutants as it travels from the paved ground and into the storm sewer system. It’s important to be aware of stormwater, where it comes from, and where it goes because it impacts water quality in our local watershed. Flooding, pollutants, erosion, and property damage can all result from uncontrolled stormwater runoff. This polluted water is not treated and goes directly into water ways. The EPA estimates that stormwater runoff contributes to 65% of pollution in receiving water bodies. 

The infiltration process is what recharges our groundwater supply. Certain methods can be utilized to lessen the amount of water that flows directly to the storm sewer. Storing and soaking up water replenishes groundwater, and greatly reduces the amount of water entering the storm sewer system.

Management of stormwater systems is the responsibility of everyone but it is generally the individual homeowner who maintains the portion of the channel on his/her property. Roadside ditches are designed to carry street runoff to the nearest wash or culvert crossing. Vegetation must be kept out of roadside ditches or closely trimmed and maintained so as not to retard flows or trap debris and clog the ditch. Many stormwater blockages in streets occur due to clogged storm sewer inlets. If there is an inlet in the street adjacent to your home, residents are asked to keep this drain clear of all obstructions including leaves, grass and debris. The purpose is to maintain the free flow of water and not impede or reduce the water carrying capacity of the tinhorn or channel. Tinhorns should not be filled in, plugged, blocked, diverted or altered in any way.

People in older neighborhoods should assess their property for tinhorn and ditch conditions as well as the slope away from the foundation. The tinhorn should be clear, currently tinhorns are required to be 18 inches in diameter. The pad should slope away from the house at a 5:1 slope, for a minimum of 10 feet.

In new developments, streets are designed and built with curb and gutter along the street and with storm sewers underneath the pavement. The curb and gutter directs stormwater from the pavement into the storm sewers. These storm sewers not only collect water from the roadway, but also connect to other drainage systems to collect water from yards and subdivisions and transport the stormwater to detention basins and other outlets.

Mustang relies on a network of swales and ditches, storm sewers, detention basins and streets.

  • Swales and Ditches – Swales are small, grass lined channels that carry water. Ditches are larger channels that have the same function but are designed to carry more water than swales.

  • Storm Sewers – Stormwater runoff from roadways, parking lots, sidewalks and lawns are usually collected by a storm sewer. The storm sewer consists of a network of inlets on the surface covered by a grate that empty into a series of storm sewer pipes. Storm sewers are designed to contain and transport stormwater from most typical storm events. Most storm sewers deposit runoff into detention basins before the water continues through the Stormwater Management System.

  • Detention Basins – A detention basin is an area where stormwater may be quickly collected but slowly released to minimize the impact on the surrounding area. Detention basins may be a pond that fills with additional water during a storm event, or a dry area that temporarily holds water during a storm event. Dry detention basins may include parks, business parking lots and portions of residential yards.


Flooding and disaster impact the community as a whole. Mustang is asking citizens to join us in becoming water wise. This comes in the form of education, understanding and responsibility. The more you know, the more you can do! One simple tip is to clean up your dogs waste. Runoff contaminated with pet waste's can contain pathogens such as bacteria, parasites, and viruses that are harmful; causing sore throats, intestinal problems, rashes, nausea, and infections. Pet waste demands oxygen to decompose, this reduces the amount available to fish and plant life, causing them to die. Pick up poop and properly dispose of it. Many stormwater contaminants are made up of common items used by most of us such as fertilizer, car oil and grease, yard clippings, soil, and pet waste. There are simple and low cost changes that you can make in your daily life that can help to prevent stormwater pollution. 

Poor drainage and low spots can lead to flooding and soggy spots in the yard. Since water follows the natural downward flow of the land, some simple redirection can help keep it moving off your property. In some cases, the best way to keep your yard from flooding will involve more than one method of controlling the rainwater.

The key to management is maintenance. Maintain culverts and channels, clean out tinhorms and gutters. These systems are ineffectual if they are not properly taken care of. Clean gutters regularly, remove dirt and blockage from tinhorns, maintain the slope of the channels. However, there are many additional methods to choose from, each requires care in order to perform. 

Homeowners can take additional steps to mitigate stormwater on their personal property. Home Advisor Website

All construction sites within the City of Mustang must comply with rules and regulations set forth by the Oklahoma Department of Environmental Quality. Please contact the Community Development Department for more information about our Stormwater Quality Program. If you wish to report a complaint or concern regarding a development under construction, please contact the Community Development Department at 405-376-9873. 

The New Approach to Stormwater Management 

In the past, stormwater management was addressed solely through infrastructure. Infrastructure fails over time from wear and quickly becomes outdated and ineffective. The current system attempts to capture runoff and quickly move it from its natural path to a series of channels and pipes that deposit the water into a receiving water body. In a natural system water is dispersed across the landscape along a path. It is infiltrated into the ground, absorbed by plants and evaporated back to the atmosphere. 


Infrastructure is costly to build, costly to maintain and costly to upgrade. Employing green methods will lessen the burden on the infrastructure along with benefitting the environment. Green stormwater management seeks to replicate the natural process that has been lost to urbanization. These methods have been adopted across the United States with success. As stated earlier; slow, soak and release. There are many ways to do this, the method employed will depend on drainage assesments, individual needs and lot characteristics. Going green can be as easy as adding gutters to your house and directing the downspout to the yard and not the driveway. 

The water wise program will provide a guide to installing your preferred method of stormwater management and reuse.  Workshops and events will be available in the near future. 

Supporting Documents

City of Mustang's current Stormwater Management Plan (SWMP)

OSU Guide to Water Wise Landscaping (12 MB)

OSU Guide to Understanding Stormwater (848 KB)

ODEQ What is Stormwater (1 MB)

How to Drain Your Pool (54 KB)

Mustang MS4 NPDES Phase II Permit Annual Report 2019 (4 MB)

Mustang MS$ NPDES Phase II Permit Annual Report 2020 (448 KB)