Annual Municipal Separate Storm Sewer System (MS4) Status Report (2021-2022)
Welcome to the Borough of Carlisle’s Stormwater Management Information page. This page is designed to provide Borough residents and businesses with access to information, tools and resources to help preserve and protect clean water in the Borough and downstream communities. We hope that you will find this information useful. Please remember that actions taken by both residents and businesses can have a positive impact on our water resources.
What is Stormwater Runoff?
Stormwater runoff is water from rain or melting snow that “runs off” across the land instead of seeping into the ground. It is created when rain or snow falls on roads, driveways, parking lots, rooftops and other covered surfaces that do not allow water to soak into the ground. Stormwater runoff is the number one cause of stream impairment in urban areas such as the Borough of Carlisle.
Most of the rain and snow falling within the Borough eventually enters area waterways. The Borough operates and maintains a storm sewer system to collect runoff from streets and other impervious surfaces and conveys the water to area streams. Carlisle’s Municipal Separate Storm Sewer System (also referred to as its MS4) includes over 28 miles of underground pipes and over 2,000 street inlets. The Borough also owns the land just west of W. South Street and S. Orange Street. This large field is used to capture and temporarily hold stormwater before it is released into storm sewers.
As stormwater flows over streets, sidewalks, lawns, and other areas; it can pick up pollutants such as motor oil, road salt, pet waste, fertilizers, pesticides, and debris. The stormwater eventually travels through the storm sewer system and is discharged untreated to either Letort Spring Run, Conodoguinet Creek, or Alexander Spring Creek, impacting area water quality.
In addition to Borough owned and maintained facilities, there are numerous private facilities, such as detention basins, vegetative swales, and other landscaped areas, that help manage stormwater and reduce runoff.