Stormwater – precipitation that does not soak into the ground – can have a large impact in a short amount of time. Rain falling on a grassy area is slowed by the leaves and stems; these areas hold about 90% of the water. Rain falling on a paved driveway picks up momentum as it flows toward the nearest low spot; these areas catch very little water. Each new stretch of pavement or hard surface in a town sends more runoff toward drainage systems.
How much runoff are we talking about? That depends on where the rain is falling. In Grand Island, we can find:
– average annual precipitation: 26 inches
– recent size of the city: 30 square miles
So if 1 square mile receives 26 inches in 1 year, and Grand Island is about 30 square miles, then Grand Island receives about 521.4 million gallons of precipitation each year.
But Grand Island isn’t all hard surfaces or all green space, we have a mix. Experts in this area agree that small urbanized areas in rural communities lose about 30% of precipitation as runoff. Another quick calculation (30% of 521.4 million) gives us about 156.4 million gallons each year that don’t soak into the ground. 156.4 million gallons of water rushing off to… somewhere.
Residents of Central Nebraska rely on clean water.
Tourism in Central Nebraska relies on clean water.
