What is Stormwater?
In undeveloped landscapes, rainwater runoff is part of the natural hydrologic cycle. Vegetation, soils, and a wide range of organisms filter, absorb, and use rainfall in their living processes. Evaporation and transpiration takes place, and this completes the cycle. Excess precipitation infiltrates into groundwater and flows into surface waters, recharging aquifers, and supporting aquatic life. The entire system is affected when the landscape is changed: impervious surfaces (paved streets, parking lots, rooftops, etc.) prevent stormwater from percolating into the ground and cause it to pick up debris, sediments, chemicals, and other pollutants as it moves over the ground.
Diagram overlaying the hydrologic cycle and how the process works (University of California, San Diego).
Why is Stormwater Management Important?
Stormwater management is essential to prevent erosion of agricultural, developed, and developing areas. Failed stormwater practices, or a lack thereof, can cause severe damages and flooding. Any new development will have some impact on the surrounding environment; the construction of buildings and infrastructure will significantly alter the hydraulic properties of an area. Pervious surfaces, or surfaces that allow stormwater to percolate and infiltrate the ground below, often become less permeable or impermeable and prevent percolation once development takes place.
Municipal Separate Storm Sewer System (MS4)
An MS4 is a system of conveyances owned by a public entity and discharges stormwater runoff to waters of the Commonwealth. The system is designed to collect or convey stormwater. Please note that the storm sewer system is not a combined sewer system. The Township’s stormwater conveyance system, unlike the sewer system, conveys surface water runoff from rain, irrigation, and outdoor water use directly to our waterways without treatment. The stormwater conveyance system includes streets, sidewalks, curbs, gutters, ditches, man-made channels, catch basins, and storm drain inlets. In Lower Macungie Township, the stormwater conveyance system ultimately discharges to the Lehigh River, which then flows westward to its end point at the Delaware River. In our Township, the MS4 is monitored for erosion, flooding, and spills to ensure the best quality runoff into our waterways.
Diagram showing how the municipal storm sewer system and its components work to convey stormwater flows (Lake County Ohio).
For a better explanation of stormwater and why it should matter to you, please view the following video: After the Storm (Environmental Protection Agency).
After the Storm - Environmental Protection Agency 2006 - EPA 841-C-06-001 - After the Storm: Co-Produced by the U.S. EPA and The Weather Channel. The show highlights three case studies—Santa Monica Bay, the Mississippi River Basin/Gulf of Mexico, and New York City—where polluted runoff threatens watersheds highly valued for recreation, commercial fisheries and navigation, and drinking water. Key scientists and water quality experts, and citizens involved in local and national watershed protection efforts provide insight into the problems as well as solutions to today's water quality challenges. After the Storm also explains simple things people can do to protect their local watershed-such as picking up after one's dog, recycling household hazardous wastes, and conserving water. The program is intended for educational and communication purposes in classrooms, conferences, etc.
WE NEED YOUR HELP TO KEEP OUR RIVERS AND STREAMS HEALHTY!
Erosion & Sediment Control Hotline – (610) 391-9583
If the stormwater is “cloudy” or “dirty” and originated from an area of active earth disturbance, you will receive the quickest response by calling the Lehigh County Conservation District at 610-391-9583. The Conservation District is responsible for investigating all erosion and sediment control concerns for the Township. Please provide your name, address, telephone number, and the specific location of the origin of the sediment laden runoff.
Illicit Discharge Hotline – (610) 966-4343 or 911
If you witness a potential illicit discharge into waters of the Commonwealth, or any other event that could adversely affect water quality, please contact Lower Macungie Township at 610-966-4343. It would also be wise to contact the Lehigh County Office of Emergency Services by dialing 911, or the Department of Environmental Protection’s Northeast Regional Office at 570-826-2511.
Please stay tuned for more updates.
- Chapter 23A: Little Lehigh Basin Stormwater Management Ordinance
- Chapter 23B: Perkiomen Creek Headwaters Act 167 Stormwater Management Ordinance
- Chapter 23C: Lower Macungie Township Municipal Separate Storm Sewer Systems
- Lehigh County Conservation District
- Partnership for the Delaware Estuary
- Pennsylvania Emergency Management Agency
- Pennsylvania Department of Environmental Protection
- PA DEP Erosion and Sediment Pollution Control Program Manual
- PA DEP MS4 Resources and Education
- Pennsylvania Organization for Watersheds and Rivers
- Stormwater PA MS4 Program
- US Environmental Protection Agency