Runoff Water

How important is the Earth's runoff water? Even though we don't hear much about it, it's all around us.

When rain or snow falls onto the earth, it starts moving down the soil. A portion of the water seeps into the ground to replenish Earth's groundwater.

The other portion of it flows downhill as runoff. Runoff is extremely important in that not only does it keep rivers and lakes full of water, but it also changes the landscape by erosion. Flowing water is so powerful that it can move boulders and carve out canyons like the Grand Canyon. During storms, is when we get most of our runoff water. This water flows into rivers and streams.

Some meteorological factors affecting runoff are for instance, type of precipitation, rain, snow, sleet, rainfall, intensity, amount, and duration. Some physical characteristics affecting runoff are land use, vegetation, soil type, drainage area, basin shapes, elevation, slope, topography, drainage network patterns, and ponds.

Moreover, in storm runoff and water quality the majority of storm water is absorbed by the soil, which is called infiltration. This water is stored as ground water and slowly discharges into the streams. In these conditions flooding is less significant because some of the runoff from a storm is absorbed by the soil.

As watersheds develop by our urban cities, much of the natural soil is turned into impervious surface. These man made surfaces reduces the area where water can be absorbed by infiltration. Thus more runoff water occurs and now human made drainage systems, curbs, and ditches carry most of the water directly to the streams. Simply put, developed watersheds carry the runoff water more quickly to the streams, resulting in an increasing of the likelihood that more floods will occur. 

How do we take care of this problem? Well we use drainage ditches that carry off the storm water runoff to storage ponds and these often hold off and collect sediments in order to keep it going out to streams.

Also runoff from farms and even your own yard carry extra nutrients, like nitrogen and phosphorus into streams, lakes, and groundwater drinking water. All the excess nutrients can degrade our water quality we use for drinking, swimming, and fishing.

Runoff water is an important factor for us and we can make changes in our habits to keep our water safe. We can do this by limiting the pesticides in our yards. Also, by not dumping paint, used motor oil, and insecticides into the ground or into storm drains. To limit flooding we can limit the times we water our yards and cover piles of dirt or mulch being used in landscaping projects. All these precautions can prevent extra sediments in our groundwater. If we take all of these measures, we will have cleaner drinking water and ultimately a heather society.

References:

http://water.epa.gov/action/weatherchannel/stormwater.cfm
http://ga.water.usgs.gov/edu/runoff.html
http://www.baysoundings.com/spring04/lid.html
http://www.portlandonline.com/bes/index.cfm?c=34598