Tuesday, July 17, 2012

Your Backyard Woods - Reducing runoff & erosion

Soil particles carried off your property by overland flow and deposited in a channel is the primary pollutant that your woodland can produce. Many woodland activities have the potential to cause soil erosion. Your goal is to keep eroded soil on your land, and not let it reach a road ditch, gully, or stream. Once the water reaches one of these channels, it will eventually be carried to a lake, reservoir, or the ocean where it will be deposited. Along the way it can harm stream fish habitat, fill stream channels, and increase water treatment costs.

Water is a product of your backyard woods and everything you do or do not do in your woods can impact it. Backyard woods management practices, such as protecting your property from wildfire, keeping your woods healthy, attracting wildlife, helping your preferred trees grow, planting trees, harvesting wood and special forest products, building and maintaining roads and trails, providing access to livestock, and doing nothing in your woods are some of the practices that can impact water production. Each practice can have either a negative or positive impact on water depending on how it is used or not used. 

Potential practice impacts on water quality are:
• Wildfires burn the litter layer and can increase erosion.
• A healthy woods produces more leaf litter, which protects the soil from rainfall impact.
• Helping preferred trees grow produces more litter on the ground and reduces fire risk.
• Large numbers of wildlife (deer, as an example) can impact tree growth, which reduces the litter layer.
• Planting trees expands your woods, and more acres of woods produce more clean water.
• Harvesting products may require machinery in your woods that can compact soil and remove litter layer.
• Constructing and maintaining roads and trails remove litter layer and compact the soil.
• Unrestricted livestock access compacts the soil and removes vegetation.
• Doing nothing may increase fire risk and reduce tree health.

Litter layer removal begins the erosion process. As raindrops fall on unprotected soil, soil particles are loosened and fill soil spaces on the surface, reducing infiltration. The water collects on the soil surface and begins flowing over the surface in a sheet. As the rain continues, sheet flow increases and forms tiny channels and these combine to form larger channels. Given enough slope and bare soil, water will reach a road ditch, gully, or a stream.

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