As noted in the history above, urban development has a profound influence on the quality of Baltimore’s waters. Rooftops, roads, parking lots, driveways and other impervious surfaces no longer allow rainfall to soak into the ground. Rainfall becomes runoff. This increase in surface water can be too much for the existing natural drainage system to handle, especially as it speeds up in man-made channels and gushes out into our streams.

The accumulation of trash, oil, fertilizers and animal waste affects water quality. Sediment from bare or poorly vegetated ground ultimately enters the Chesapeake Bay. Inflow of sediment can cloud water, blocking sunlight from reaching aquatic plants. Sediment also settles to the bottom of streams, clogging the gravel beds used by fish for laying their eggs. Nutrients, such as phosphorus and nitrogen from fertilizers enter the water and promote unusually rapid algae growth. As this algae dies, its decomposition reduces or eliminates oxygen needed for survival by fish and crabs and other aquatic life.

These are all examples of what is known as nonpoint source pollution (not from a specific source), one of the major contributors to the degradation of quality in Baltimore’s waterways. Storm water management practices help control nonpoint source pollution using structural and/or nonstructural techniques to intercept, filter and treat surface runoff, including trash, from developed areas. This water is then discharged at a controlled rate into a body of water.

The overriding condition that governs the quantity of storm water runoff is the amount of impervious surface located on public and private property (driveways, streets, roofs, sidewalks, etc.). Water that can be absorbed by vegetated and porous surfaces is naturally slowed and filtered.

Surface water quality is impacted by the accumulation of pollutants, chemicals, oil, trash and animal waste on exterior surfaces. As the use of chemicals around homes and businesses increases, the more degraded the storm water runoff will be. As litter is allowed to accumulate on sidewalks, streets, lots and alleys, damage to our surface waters occurs because this material will find its way into a storm drain.

Although the effect of one property on the quality and quantity of stormwater runoff may seem insignificant, the cumulative impact from thousands of properties across Baltimore continues to erode our water quality. Although one piece of trash on the ground from one person may seem minor, the cumulative impact of tons of litter is destroying our streams, our harbor, our Bay and our civic standing in the nation and the world.