In 2003, the City of Latrobe became one of approximately 670 small urban communities within the Commonwealth of Pennsylvania required to have its municipal separate storm sewer system (MS4) regulated under the Pennsylvania Department of Environmental Protection’s (PADEP’s) National Pollution Discharge Elimination System (NPDES) Phase II permit program for storm water discharges from storm sewer systems within small to medium-sized communities within urbanized areas as defined by the 2000 U.S. Census.
What is an MS4?
MS4 is an acronym for a Municipal Separate Storm Sewer System. An MS4 is defined as a collection and conveyance system or a group of collection and conveyance systems owned, operated and maintained by a state, city, township, borough or other public entity that is dedicated solely for the handling of surface runoff from precipitation events and discharging it into tributaries, streams, rivers, lakes or other natural or man-made receiving waters within the Commonwealth of Pennsylvania. The MS4 system may include such structures as storm pipes, catch basins, trench drains, roadside swales and cross drains, conveyance channels, detention ponds, or other structures designated for the collection and conveyance of stormwater runoff.
What is Stormwater Runoff?
Stormwater runoff is water from rainfall, snowmelt, and/or ice melt that flows over ground or impervious surfaces (paved streets, parking lots and rooftops) and does not percolate into the ground. Stormwater runoff may flow directly into natural tributaries, streams, rivers, lakes or other waterways within the Township or it is intercepted and collected by the Township’s municipal separate storm sewer system where it is then discharged at discrete locations (outfalls) into streams, rivers, lakes and other natural waterways.
What is Non-Stormwater Discharge?
Non-stormwater discharge is discharge into the City’s MS4 system or natural waterways that is not due directly to a rainfall or snowmelt runoff event. Non-stormwater discharge includes groundwater exfiltration, mine pool discharge, discharges from potable water sources such as fire hydrants or waterline blow-off valves, sanitary sewer discharges either from publically-owned treatment works collection systems or on-lot septic systems. Many non-stormwater discharges are prohibited under the Township’s illicit discharge and connection ordinance.
Why can stormwater runoff be a problem in the Township?
As stormwater runoff flows over lawns, impervious surfaces, or land disturbed by construction activities, it accumulates chemicals, oils and grease, debris and litter, sediment, heat or other pollutants that contaminate and adversely affect the water quality of our natural waterways. Also, as more impervious cover is constructed or as natural vegetation is cleared and the underlying soil is compacted, more stormwater runoff is generated. Stormwater runoff pollution can lead to deterioration of the quality of our natural waterways which are used for fishing, swimming, boating, as well as sources of our potable water supply. Increases in stormwater volume can lead to accelerated stream bank erosion and more frequent stream channel flooding which can result in damage to and loss of property as well as premature failure of roadway culverts and bridges.
What is the City doing about stormwater runoff?
As part of its MS4 permit program, the City has implemented several actions, or control measures, to ensure the proper handling and discharge of stormwater through its MS4 system. Such measures include the following:
What can residents of the City of Latrobe do to improve stormwater and public drinking quality in the City?
It takes everyone to provide continual improvement to the waterways within the City of Latrobe. We would hope that every person realizes that what is dumped into the City’s MS4 system, ultimately ends up in the Allegheny River, a source for recreation and public drinking water. Here are several things each of us can do to help keep our rivers and other waterways clean.
Related Links and more information for the City’s Stormwater Program: