HOW STORMWATER AFFECTS YOUR RIVERS

HOW STORMWATER AFFECTS YOUR RIVERS

When managed properly, this water is a valuable resource. However, when stormwater is managed like a waste product, it exacerbates flooding and becomes contaminated with pollutants.

WHAT IS STORMWATER?
Stormwater (or polluted runoff) is rain or melting snow that flows over the ground. In urban or developed areas, stormwater runs over pavement and parking lots, picking up oil and other pollutants before flowing into a nearby river or stream. In more natural areas including forests and wetlands, stormwater can soak into the ground, or be stored and filtered.

WHAT ARE THE IMPACTS OF “IMPERVIOUS SURFACES”?
Impervious surfaces such as roads, parking lots, and roofs associated with sprawling urban development significantly change natural river flow patterns and the recharge of underground water supplies.

Rainfall cannot soak into the ground through these surfaces and thus does not replenish groundwater supplies. Impervious surfaces also increase the amount and speed of water entering rivers and other water bodies.

The result is an increase in the severity and frequency of floods, the displacement and destruction of habitat for fish and other water dependent species, and a decrease in base flows in our streams and water in our aquifers.

WHAT ARE THE HEALTH IMPACTS OF POLLUTION?
Urbanization has fundamentally altered the way that water moves through the landscape. When rainwater can’t soak into the ground, it runs along streets and parking lots and picks up pollutants.

This polluted runoff can flow into our rivers and streams, or overwhelm local infrastructure to cause sewage overflows.