Since the implementation of the Clean Water Act in 1972, the Environmental Protection Agency has been able to curtail pollution to waterways from many point sources. However, pollution impacts from nonpoint source stormwater runoff continue to increase. Stormwater management has become an increasingly important topic in the state of Iowa with a large focus on finding ways of improving agricultural runoff, which pollutes streams and rivers with high nutrient and sediment loads. While the vast majority of land in Iowa is dedicated to agricultural production, there is another major culprit to non-point pollution sources: construction sites.Continue reading
Post written by Hanna Bates, Program Assistant at the Iowa Water Center
Urban zones are ever expanding in Iowa with new houses, apartment complexes, and businesses emerging every year. Construction in urban zones often causes negative impacts on the soil, including compaction, which can thwart root zone growth in green spaces and may lead to erosion and water quality impairments. A new study by Logsdon et al. in the Journal of Water Resource and Protection shows that compost has the ability to improve soil and water quality in post construction sites in urban areas.
Researchers examined lawn grass plots and prairie plots that had simulated construction activities, such as driving over the plots with a tractor. This activity mimics the increase of soil compaction that occurs at construction sites due to the heavy machinery used. The plots received a treatment with three types of compost application methods: compost with aeration, rototill and compost, and surface compost. These plots were compared against bluegrass, which is a traditional lawn grass, without compost. Plots then underwent a rainfall scenario with the use of a rainfall simulator. Researchers measured numerous variables in the soil including soil water, bulk density (the degree of compaction), and morphology (the observable elements of the soil).
The study found that the use of compost lessened the bulk density in the soil (Logsdon et al 2017). High bulk density is an indicator that the soil has low absorbency for water and limits plant growth. By lowering bulk density, there is an increased ability to support healthy plant life and increase the water retained in the soil. In this study, compost additions not only provided the benefit for soil health, but it also darkened the soil more than the addition of topsoil. The study also found that when compost was combined with prairie grasses, it increased infiltration and minimized runoff and sediment loss when compared to bluegrass lawn.
If you’re a developer or even a homeowner, it may be worthwhile to consider composting and planting prairie rather than traditional lawn grass. It will not only keep your soil in place, but it will make a positive impact on the surrounding environment and lessen the stress on the public water infrastructure.
Logsdon, S.D., Sauer, P.A. and Shipitalo, M.J. (2017) Compost Improves Urban Soil and Water Quality. Journal of Water Resource and Protection, 9, 345-357. 7. https://doi.org/10.4236/jwarp.2017.94023.
Hanna Bates is the Program Assistant at the Iowa Water Center. She has an MS in Sociology and Sustainable Agriculture from Iowa State University. She is currently pursuing an MBA with a leadership certificate from the University of Iowa.
On the [second] day of Christmas, the Iowa Water Center gave to me…descriptions for the breakout session Green Infrastructure: Function.
The following presentations will take place at the Iowa Water Conference in Ames on the afternoon of Wednesday, March 23, 2016. Registration for the conference will open in January.
Native Vegetation in Stormwater BMPs: How to Put the Plants to Work
Chant Eicke, Professional Wetland Scientist, EarthView Environmental, Inc.
Establishing vegetation in stormwater BMPs can be a nightmare, often pushing design professionals toward reliance on aggressive, non-native plant species. By utilizing a few basic planning, design, and maintenance tools, native plants can establish, flourish, and provide superior performance.
Stormwater BMP Designs – Beyond the Designs and Drainage Report
Judith Joyce, Geologist & Professional Wetland Scientist, EarthView Environmental, Inc.
Are your Stormwater BMPs ugly muddy holes, full of sediment and/or weeding vegetation? Was it designed by the numbers, yet still “wrong”? Let’s look beyond the drainage calculations to an understanding on how natural systems work.
Installed BMP’s Can Make A Difference – Come and See How
Monica Smith, PE, President/Design Engineer, Robinson Engineering Company
Robinson Engineering has worked with the staff at the University of Northern Iowa to design and install a number of Best Management Practices in one area of their campus, resulting in increased aquatic habitats and better water quality.
Water Reuse- Retrofitting Last Century Technology for the Future
Meghan Funke, Limnologist, Emmons & Olivier Resources, Inc.
We present a tool that quantifies the benefits (volume and phosphorus capture) and optimizes the design (storage volumes, operations) of stormwater reuse and harvesting systems. Scenario results using the tool show sensitivity to storage size and availability of green space.