Addressing the Issue of Increasing Stormwater Levels
Star Tribune reports of inter-community efforts to address the challenge of increasing stormwater levels brought about by the warmer climate. WET (Weather-Extreme Trends) is a study project coordinated by the Minnehaha Creek Watershed District and funded in part by the National Oceanic and Atmospheric Administration. The project aims to examine weaknesses in existing rainfall and land use trends in the area and explore ways to adapt to changing precipitation levels and patterns caused by the warming climate.
A Signature Trend
According to the study project, both climate research and present/projected weather trends indicate a substantial increase in precipitation levels in terms of both frequency and severity. Since the existing infrastructure and control measures were originally built to deal with past climate patterns, it may ultimately prove inadequate to deal with present climate patterns. Mark Seeley, a climatologist from the Universityof Minnesota Extension, stated that annual precipitation in parts of south central and southeastMinnesota went up by an estimated 15 percent. Other parts of the area also documented record levels in annual rainfall in recent years.
Unusual increase in normal rainfall levels is seen as a “signature trend” of warming climate. This is because warm air has a greater capacity for retaining water. Thermal pollution is associated with an increase in stormwater levels especially in urban areas.
Stormwater Challenges: Flooding and Degraded Water Quality
Stormwater presents several challenges to the urban community as well as to the natural environment. According to Land-of-Sky Regional Council’s fact sheet Stormwater Problems and Impacts: Why All the Fuss?, flooding and degraded water quality are the two major concerns. Increased stormwater levels can cause flooding if existing control measures are not enough to adequately handle the volume. Especially in urbanized areas where impervious surfaces (roads, parking lots, asphalt, etc.) have interfered with natural hydrology, this is a serious issue. Natural ground cover allows 25% shallow infiltration, 25% deep infiltration, 40% evapotranspiration, and only 10% runoff. But covering the natural ground with impervious surface by only 10-20% doubles the amount of runoff. A 35-50% impervious surface covering equals 30% runoff, and a 75-100% impervious surface covering results in 55% runoff. Failure to control heavy stormwater runoff results in public and private property damages including sewer line washouts, sediment deposition on roads, bridge damage and others.
The uncontrolled flow of stormwater runoff also degrades water quality due to the pollutants the runoff carries. This may include sediments, fertilizer chemicals, bacteria, grease, oil, trace metals, and even thermal pollution, which can severely harm marine habitats once they reach streams, rivers, and other bodies of water.
A Timely Effort
Addressing the challenges of a warming climate such as increased stormwater levels is a timely effort. System inventory, hydrologic studies, and control measure options need to be integrated in the community stormwater control plan. Preventive measures which focus on civilian behavior and attitude change is an inexpensive and effective way to address the issue at the individual level. Investing on improvement of control measures which focus on structural defenses and practices can also help in preventing heavy losses in the future.
Programs like WET help to bring down the issue of climate change to local communities in an actual, practical level. By involving the local community, people can relate as well as respond to this critical issue by their individual and community efforts.
Reasons to JOIN US include:
- It's absolutely FREE!
- Get Green Tips You MUST know about.
- How to's on going green, saving money, and having fun.
- Keep up-to-date on our posts in cased you missed them.