Stormwater is precipitation (usually rain, but snow counts too) that does not seep into the ground, but runs off into our storm drain systems, where it eventually flows into our streams and lakes. Impervious surfaces such as roads, parking lots, driveways, and roofs that are common in urban areas, prevent the rainwater from percolating into the ground and increase the amount of stormwater runoff.
Stormwater is not treated before it is discharged into our waterbodies. Thus, anything that stormwater comes into contact with as it flows over the landscape can contaminate it. Polluted stormwater runoff can be harmful to plants, fish, animals, and people. Some of the most common contaminants that are found in stormwater are listed below:
Sediment can cloud the water and make it difficult for aquatic plants to grow. Plants form the base of the food chain and provide nourishment and habitat for fish and other aquatic life. In addition, much of the sediment is deposited into the storm drain system, never reaching a waterbody; this reduces the drainage system capacity and increases the chance of flooding.
Excess nutrients from lawn fertilizers can cause algae blooms that form green scum on the surface of the water. When the algae die, their decomposition removes oxygen from the water. Fish and other aquatic organisms cannot exist without oxygen. The low oxygen level in the water can lead to massive fish die-offs, called fish kills.
Bacteria and disease causing organisms can be transported into waterbodies from pet waste or raw, untreated sewage. If the water is used for recreational purposes (fishing, swimming, boating), these contaminants can create health hazards.
Debris and trash such as plastic bags, cans, bottles and cigarette butts can choke, suffocate or entangle aquatic life including ducks, fish, turtles, and birds when washed into our waterbodies. This debris and trash can also build up in the storm drain system, reducing flow and capacity, thus increasing the chance of flooding.
Household chemicals like insecticides, pesticides, paint, solvents, used motor oil, and other auto fluids can poison aquatic life.
Metal particles deposited on roadways from automobiles can be washed into the storm drains when it rains. Metals have a tendency to bioaccumulate in the environment, meaning that as small fish become contaminated with metals and are eaten by progressively larger fish, the concentrations of metals in the fish tissue continue to increase. This poses a significant health risk for humans that consume tainted fish.
Polluted stormwater can also affect drinking water sources and can impact human health and increase drinking water treatment costs. Stormwater runoff from Tyler flows to one of the following creeks:
- Black Fork Creek
- Gilley Creek
- Indian Creek
- Shackleford Creek
- West Mud Creek
- Willow Creek
A portion of our stormwater runoff flows into Lake Tyler, one of the primary sources of drinking water for the City of Tyler. Drinking water is treated to remove harmful contaminants and make it safe for human consumption. Higher concentrations of contaminants in the stormwater require more treatment to make the water safe for us to drink. The goal of our Stormwater Management Program is to reduce the amount of stormwater pollution that enters our streams and lakes and improve the quality of life in our City.