Stormwater is generally rain that runs off surfaces that cannot absorb water. These surfaces include rooftops, pavement, and compacted gravel lots. As water flows on these surfaces towards the storm drains, it picks up pollutants such as sediment, pet waste, oil, grease, fertilizers, chemicals, and whatever else is on the ground and makes its way untreated to local ditches and canals, eventually reaching the Laguna Madre.

Our storm drain system, unlike the sanitary sewer system that comes from your house, receives no treatment before it eventually reaches the Laguna Madre. The pollutants it picks up on its way have the potential of harming fish, wildlife, and polluting large areas of water.

Land that is undeveloped absorbs approximately 90% of all rain. As an area develops and the amount of open space is decreased by parking lots, roads, and buildings, the absorption rate during rains decreases to approximately 35%. This excess runoff caused by the decrease in absorption can cause flooding. In addition, garbage picked up by these waters can clog the drainage system, causing a slowdown in the drainage ability of the City’s system. A combination of these two events has the potential to cause flooding within the City.

The water that drains into the stormwater system makes its way to the Hidalgo County Drainage District’s stormwater system, and eventually ends up at the Laguna Madre’s Tidal Segment 2491 at the outfall just south of Port Mansfield. These waters are listed in the Texas Draft 2010 303(d) List of Impaired Surface Waters. They have been found to contain bacteria and depressed dissolved oxygen. This means the water does not have the peak oxygen needed to sustain fish and other wildlife.

Over fertilizing your lawn or fertilizing before a storm, not picking up pet waste, blowing grass clippings or leaves into the street, and washing your car in your driveway are all things that impact the stormwater system. The golden rule is: "Only Rain Down the Drain."

For a more in depth look at what the stormwater program does for grass clippings and other illicit discharges please see the presentation below:

• Organic Impact on Flood Stormwater Management

Note: While most pollution is accidental, some people deliberately dump chemicals or waste directly into storm drains. If you witness someone dumping materials into the drainage system: Do not take it upon yourself to stop them. Take down their license plate number if you can, and call the police department immediately. This type of activity is illegal and will be handled through ticketing, fines, and in some cases jail time. If possible, call the Stormwater Specialist at 956-388-8210 or the Stormwater Hotline at 956-388-8999.