With climate changing causing major shifts in weather behavior and ecosystem conditions, a focus in urban cities concerns the development of “green infrastructure” to tackle urban flooding and runoff into streams and lakes.
The city of Madison is offering to fund a rainwater collection features as part of a $290,000 study aiming to evaluate infrastructure used to gather and redirect rainwater. In a West Side neighborhood near Westmorland Park, Madison is offering up to $1,000 to homeowners if they install features such as rain gardens and porous pavement that prevent water from entering storm sewers.
In areas with greater natural coverage such as trees and grass, around 50% of rainfall reenters the earth, 10% goes as runoff, and the remainder evaporates. In contrast, in compact urban spaces, over 50% of rainfall goes as runoff. This runoff puts stress on environmental networks to absorb and appropriately drain the water, and recent years have shown the consequences as streets frequently flood.
The city seeks to encourage construction of water-absorbing “green infrastructure” on private properties in the 605-home study area. This area constitutes approximately 7% of Lake Wingra’s watershed. The city hopes to increase water infiltration by 6 million gallons per year with this new construction.
Residents of the property will be offered reimbursements for 80% of up to $1,000 in costs for new installations and projects approved by engineering departments. If property owners decide to perform the work themselves, they are eligible for 110% reimbursements, with a maximum of $1,000.
This “green infrastructure” study and construction is a response to previous years of urban flooding from major rainstorms in 2017 and 2018. These events are anticipated to occur more frequently in the future with warming climates, urging city council and engineers to develop plans for watersheds and infrastructure to keep rainwater from entering lakes and rivers.
Adding on to this pilot study, the city plans to replace sewage and storm pipes near Topfer Avenue. This will come along with new installations of pavement that allow water penetration, enhanced stormwater terraces to gather water, and rock cribs designed to collect water underground.
Eventually, researchers with the U.S. Geological Survey will perform analysis of the efficiency and effectiveness of these developments on preventing runoff and restoring and stabilizing natural ecosystems. Researchers hope that, through this study, the affects of green infrastructure on stormwater reduction will be quantified. This study will help ensure the success of natural lands and public spaces across the city.
[Sources: Wisconsin State Journal; City of Madison; Dane County]