Municipal Separate Storm Sewer Systems (MS4)
The City of Monroe’s permit requires the City to prevent the discharge of pollutants into our streams and waterbodies.
MONROE, LA
Municipal Separate Storm Sewer Systems (MS4)
What is MS4?
A Municipal Separate Storm Sewer System (MS4) is a publicly owned system of conveyances, including roads, ditches, catch basins, curbs, gutters, and storm drains, designed to collect and transport stormwater runoff. Unlike sanitary sewers that carry wastewater to treatment plants, MS4 systems discharge untreated stormwater directly into local streams, bayous, and other water bodies.
The City of Monroe’s MS4 permit, issued by the Louisiana Department of Environmental Quality (LDEQ), requires the City to develop and implement a Stormwater Management Program that reduces the discharge of pollutants to the maximum extent practicable. This program protects water quality in our local waterways and ensures compliance with the federal Clean Water Act.
Why Stormwater Management Matters
When rain falls on streets, parking lots, rooftops, and other hard surfaces, it cannot soak into the ground. Instead, this stormwater runoff flows across the land, picking up pollutants before entering the storm drain system. Since this water receives no treatment before reaching our waterways, preventing pollution at the source is essential.
Common stormwater pollutants and their effects include:
- Sediment: Soil particles clog storm drains and increase flooding risk. When deposited in streams and bayous, sediment smothers aquatic habitats and degrades water quality.
- Excess Nutrients: Fertilizers and organic waste promote excessive algae growth, which depletes oxygen in the water and creates conditions where fish and other aquatic life cannot survive.
- Bacteria and Pathogens: Pet waste, failing septic systems, and sanitary sewer overflows introduce harmful bacteria that pose risks to public health and can result in waterway advisories.
- Household Chemicals: Oil, antifreeze, pesticides, paints, and cleaning products are toxic to aquatic life. Even small amounts can contaminate large volumes of water.
- Trash and Debris: Litter that enters storm drains accumulates in waterways, harms wildlife, and degrades the appearance and recreational value of our water resources.