Why Stormwater Matters

Impacts of Runoff on Henry County Watersheds

Land development has a profound influence on the quality of Henry County waters. To start, development dramatically alters the local hydrologic cycle which is the process by which the majority of rainwater, falling on undeveloped land, infiltrates into the soil and slowly makes its way to creeks and lakes. The hydrology of an undeveloped site changes during the initial clearing and grading that occur during construction. Trees, meadow grasses, and agricultural crops that once intercepted and absorbed rainfall are removed and natural depressions that temporarily pond water are graded to a uniform slope. Cleared and graded sites erode, are often severely compacted, and can no longer prevent rainfall from being rapidly converted into stormwater runoff.

The situation can worsen after construction. Roof-tops, roads, parking lots, driveways and other impervious surfaces no longer allow rainfall to soak into the ground. Consequently, most rainfall is converted directly to runoff while ground water flows slow to a trickle. The increase in stormwater runoff can be too much for remaining natural drainage systems to handle. As a result, the natural drainage system is often altered to rapidly collect runoff and quickly convey it away (using curb and gutter, enclosed storm sewers, and lined channels). The stormwater runoff is subsequently discharged to streams, reservoirs or lakes. The following example demonstrates the effect of stormwater runoff.

Click the image above to view a larger image.

The overriding condition that governs the quantity of stormwater runoff is the amount of impervious surfaces located on your property (driveways, roofs, carports, sidewalks, etc.)

Stormwater quality, however, is governed by the accumulation of pollutants on the entire surface area, regardless of whether it is grassed or paved. As the use of chemicals around the home such as fertilizers, pesticides, herbicides, engine oils, anti-freeze and similar products increases, the more degraded the stormwater runoff from your property will be.

Although the effect of one property on the quality and quantity of stormwater runoff may seem insignificant, the cumulative impact from hundreds of thousands of properties across the State is destructive to our water quality. The following activities will minimize stormwater runoff from your property:

• Limit the amount of impervious surfaces in your landscape. Use permeable paving surfaces such as wood decks, bricks, and concrete lattice to allow water to soak into the ground. Where possible, direct runoff from impervious surfaces across vegetated areas.
• Allow "thick" vegetation or "buffer strips" to grow alongside waterways to filter and slow runoff and soak up pollutants.
• Plant trees, shrubs, and groundcover. They will absorb up to fourteen times more rainwater than a grass lawn and they don't require fertilizer.

For more information on environmentally friendly planting and landscaping designs, contact Henry County Stormwater Management Department or the Henry County Extension Office.

Additional activities that will reduce fertilizer, pesticide, and sediment runoff:

• Use natural alternatives to chemical fertilizers and pesticides.
• If you must use fertilizers or pesticides, test your soil to determine the appropriate amount.
• If a lawn care company services your lawn, make certain it is not applying "blanket" applications of fertilizer and pesticides.
• Ask if they have conducted soil tests and a pest analysis to determine appropriate applications.
• Also, re-sod or reseed bare patches in your lawn as soon as possible to avoid erosion.