Stormwater Management
Permeable Pavement
"When it rains it drains." Illinois State University was the first public university in the State of Illinois to install pervious concrete to address water quality runoff. Pervious Concrete allows water to flow through the concrete and seep into the ground water.
First installed in the G-73 parking lot (Main Street- Hancock Field), the project was used as a training session for area contractors, the Illinois Ready Mix Concrete Association, and the Indiana Ready Mix Concrete Association. There are now a total of three permeably paved lots. The second was installed in 2006 in the G-86 parking lot (School and Willow). In 2009, a third lot was completed on Gregory Street near the new recreation fields.
This project drains all storm water runoff through pervious concrete. It is designed not only to address "first flush" requirements, but can store up to 1 (one) inch of rain fall under the parking lot to percolate back into the soil, or the water can be directed to the storm water system after flowing through the underground gravel bed.
Photos of the Process
Concrete diagram.
Preparing the site to install the permeable pavement.
Laying the aggregate.
Installing the porous drain.
Demonstrating how it works.
Bioswales
The expansion of the Town of Normal’s Constitution Trail, through campus provided the Grounds department an opportunity to install the campus's first bioswale to handle water runoff. The Trail runs through the parking lot behind Redbird Baseball field, which sheet drains into nearby Sugar Creek. A 10' wide by 150' long strip of asphalt was excavated, and two and half feet of sandy soil mix was installed in its place. Both an erosion control and wet-meadow seed mix was specifically selected and sown. The bioswale is slightly concave in an effort to store some runoff as water percolates into the soil.
A second and larger bioswale was installed on Gregory St. near the recreation fields. Water that is filtered through the permeable concrete from the adjacent parking lot is directed into the bioswale for double stormwater protection!
Bioswale Sign
The sign, located off of the Constitution trail and reads:
This is a Bioswale
A bioswale is a low-gradient basin system which contains a dense cover of vegetation and is used to maintain and clean runoff during storm events. The gentle grade of the land slows the water flow, while the soil and vegetation filter and store runoff, removing 30% to 80% of pollutants such as petroleum products, excess nutrients, metals and sediments that may be found in stormwater. In other words, the bioswale acts like a sponge, absorbing rain water and slowly filtering and releasing it further into the ground. This promotes ground water recharge through infiltration and in turn minimizes stormwater runoff into streams and rivers. It is an environmentally sensitive approach to pollution control that adds natural beauty to the community and provides a haven for many mammals and birds.
Rain Garden
In the fall of 2009, the University installed its first rain garden. Rain gardens are landscape features that are designed with stormwater retention as a primary goal. These gardens use different media such as rocks and mulch to reduce erosion and increase water absorption. Plants are selected that can withstand saturated soils and higher concentrations of nutrient like nitrogen and phosphorus that are common contaminants of stormwater runoff.
Check out the before and after photos of the rain garden installation.
Before.
Installing the rain garden.
After the rain garden is completed.
