Soil's Role In Storm Water Management

In celebration of the International Year of Soil 2015 (IYS), the Soil Science Society of America (SSSA) is coordinating a series of activities throughout to educate the public about the importance of soil. April’s theme is “Soils Clean and Capture Water”. In SSSA’s April 1 Soils Matter blog post, experts explain why communities are using more storm water management features (https://soilsmatter.wordpress.com/2015/04/01/why-are-cities-using-retention-basins-and-rain-gardens/).

According to Gary Pierzynski, as towns grow into cities, more of the earth’s surface is covered with impervious materials. This creates a need for systems to manage the runoff. Pierzynski is a soil scientist and professor at Kansas State University.

“Consider a highly urbanized area that might have more than 95% of the area covered by buildings or pavement,” says Pierzynski. “These surfaces essentially absorb nothing. All the rainfall becomes surface runoff. The amounts can be significant.” A standard city block (1/8 mile by 1/8 mile, about 10 acres in size) creates nearly 300,000 gallons of surface runoff from a one-inch rainfall if none of it enters into the soil. Even residential areas can have more half the surface covered with prohibitive surfaces.

Under-designed storm water systems contribute to urban flooding during heavy precipitation events. The design has to handle the total amount of normal runoff as well as the peak amount. Five inches of rain falling over 24 hours creates a much different storm water need compared to five inches of rain falling in two hours!

Newer developments are correcting previous mistakes. Concrete-lined channels prevent erosion at high flows and pumping stations to keep water moving if the natural landscape does not provide gravity flow.

There is also an increased focus on cleaning the runoff by using the natural cleaning ability of soils. “Everything you see on streets and sidewalks--salt, petroleum products, pesticides, plant nutrients, litter, and other contaminants--moves with the runoff. Often it ends up in local lakes and streams as pollution. Rain gardens and retention basins allow water to flow more slowly and naturally through soil.” This facilitates the removal of many of these undesirable materials.

Finally, city planners know to look to the future. One prediction with global climate change is less frequent but more intense storm events. This suggests a need to enhance our storm water management capabilities, before we need it!

As part of their celebration of IYS, SSSA is developing a series of twelve 2-minute educational videos. April’s Soils Clean and Capture Water video can be viewed at www.soils.org/iys/monthly-videos. Educational materials can be viewed atwww.soils.org/iys by clicking on the April tab.

For more information, visit www.soils.org/discover-soils, www.soils4teachers.org,  www.soils4kids.org.

The Soil Science Society of America (SSSA) is a progressive international scientific society that fosters the transfer of knowledge and practices to sustain global soils. Based in Madison, WI, and founded in 1936, SSSA is the professional home for 6,000+ members and 1,000+ certified professionals dedicated to advancing the field of soil science. The Society provides information about soils in relation to crop production, environmental quality, ecosystem sustainability, bioremediation, waste management, recycling, and wise land use.