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​Q. I am hearing more and more about stormwater runoff and how it affects our environment. Considering the large amount of rain that we've seen in the last few weeks, I want to figure out how I can keep more water in my landscape instead of watching it run down the street drain. Is this a silly idea?

A. This is a great idea!! The ways we design and manage our properties directly affects Alabama's waterways – positively or negatively.

wp street trees - aug 2011 012.JPGIn natural areas such as forests, heavy rains seep into the soil. However, in human-built landscapes, water often runs from impervious surfaces such as roofs, walks, and drives directly into our waterways. This "stormwater" can significantly impact our watersheds - surface water such as rivers and lakes, and groundwater from which many of us get our drinking water.

Excessive flows of stormwater cause severe damage as it flows overland; often creating flooding and stream bank erosion. Rapidly moving, high volume runoff doesn't have time to percolate into natural areas and washes excessive sediment into rivers and streams. Muddy, cloudy water is harmful to plants and fish, giving room for invasive species to thrive. Excessive water flowing across our landscapes washes oil and lubricants from your car, and other materials into our water systems. Fertilizers and pesticides, especially when left on the driveway, are flushed into rivers and streams. These contaminants also mean a higher cost to cleaning this water before we can use it for drinking water.

To minimize the negative impacts of your landscape on our watersheds, consider these practices before applying pesticides to your landscape.
• Put the right plant in the right place. Healthy, stress-free plants suffer less from pests.
• Identify the plant first.  Be aware of its normal, healthy appearance.
• Identify the pest second. Not all suspicious characters cause problems.
• Read and abide by the pesticide label.  THE LABEL IS THE LAW.
• Avoid having leftover chemicals. When choosing chemical controls, buy and mix only what you need.
• More is not better.  Use the lowest labeled concentration rate that will get the job done.
• Protect beneficial creatures. Spot treat the pest and avoid broadcast applications of pesticide.
•Follow the label instructions for disposal. Do not put unused pesticides in household garbage containers.

Changes to your landscape design can also help reduce the adverse effects of stormwater runoff.

--Drip-line infiltration trench. This is simply a trench, about 18-inches wide and about 8-inches deep, with crushed stone of various sizes in layers, under the roof drip line. Think of it as a dry stream bed. It captures heavy roof runoff, allowing it to seep into the soil naturally. It works best in sandy or well-drained soils; otherwise you may need to install a perforated PVC pipe as well in the trench.

--Pervious walkways and patios. Or install strips of permeable material surrounding or disecting a large paved area. Lay bricks, flagstones, or other pavers in a bed of sand or small gravel. Water can soak between pavers into a stone reservoir underneath if the area receives excess water. You can find pervious pavers for driveways, as well.

--Rain barrels. Place these large drums, often plastic and 55-gallon capacity or similar, under downspouts to collect water for later use in watering plants. Make sure and empty between rains to ensure there is enough space to capture runoff from large storms. Cisterns are larger capacity versions.

--Rain gardens. These bowl-shaped gardens utilize soil, mulch, and plants to absorb runoff and allow it to then seep into the soil naturally. When making your selections, do a little research to find plants that will handle dry periods as well as standing in water for a short amount of time. Native flood-plain plants often fit the bill.

--Water bar. If you have a moderately steep path, drive, or walk, consider adding one of these. Bury a 6- or 8-inch wide rot-resistant timber across the path at an angle, with a trench of similar depth on the upward side, lined with geotextile (like weed barrier) fabric and filled with crushed stone. As water flows down the slope it will soak into the trench, then the timber directs it to the side where it can infiltrate.

Everyone can contribute to maintaining high water quality for Alabama.  Learn more by using our Smart Yard information at www.aces.edu .

written by Bethany A. O'Rear of the Alabama Cooperative Extension System, C. Beaty Hanna Horticulture & Environmental Center, which is based at the Birmingham Botanical Gardens.


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