Stormwater Science: Recent Research Highlights

In recent years, scientists have become increasingly concerned about new types of contaminants in our water, including microplastics, tire wear particles, antibiotic resistance genes, and per- and polyfluoroalkyl substances (PFAS). These pollutants can cause problems for fish, plants, and even human health if they end up in our rivers, lakes, and oceans. A recent review by Bodus et al. (2023) examines how these emerging contaminants interact with green stormwater infrastructure and explores potential design modifications to enhance their removal. While source reduction remains the best option for addressing these contaminants, the authors found that properly designed green stormwater infrastructure can serve as an important line of defense.

To maximize removal of these emerging contaminants, the authors found specific design modifications are needed for different green infrastructure practices. For microplastics and tire wear particles, bioretention systems and rain gardens should incorporate finer filter media and increased depth to enhance filtration. Adding a pre-treatment zone with coarser materials can help trap larger particles before they enter the main system. To address antibiotic resistance genes, designers should focus on increasing clay content in the soil media to promote adsorption and consider regular replacement of the top layer to prevent accumulation. For PFAS removal, incorporating specialized adsorbents like activated carbon or biochar into the soil mix can significantly improve performance. Constructed wetlands can be optimized by selecting plant species known for their ability to uptake and metabolize PFAS. Across all practices, increasing the hydraulic retention time through design features like check dams or internal storage zones can provide more opportunity for contaminant removal. While thermal pollution is also a concern, it can be mitigated through deeper soil profiles and shading strategies. By tailoring these design elements to target specific emerging contaminants, green stormwater infrastructure can more effectively protect our water resources from these new environmental threats.

Iowa News

EPA Enforcement Action Highlights Importance of Stormwater Management

In a recent enforcement action, the EPA fined Linwood Mining and Minerals Corporation $23,244 for alleged Clean Water Act violations at their Davenport, Iowa facility. The company was found to have discharged pollutants into Donaldson Creek, a tributary of the Mississippi River, in violation of their permit. This action serves as a crucial reminder of the importance of proper stormwater management for industrial facilities.

This case highlights the ongoing challenges in managing industrial stormwater runoff. To assist those facilities impacted by General Permits 1 and 3, ISWEP offers an industrial stormwater management training webinar during the summer. These sessions provide valuable updates on regulations and best practices. We encourage facilities to take advantage of this resource to assist with permit compliance and ensure their stormwater management plans remain effective and up-to-date.

Iowa Stormwater Management Manual Updates

IDNR will soon publish the following updates/new sections in the Iowa Stormwater Management Manual: stormwater management criteria; grass swales; vegetative filter strip; sediment forebay; hydrodynamic separators; catch basin sumps and inserts; tree and planter systems, and underground detention. The ISWMM committee will develop a new rainwater harvesting chapter over the next year.

IDALS Request for Pre-Applications for WQI Urban Conservation Projects

The Request for Pre-Applications for WQI Urban Conservation Projects is now available at the following link on the IDALS website.

Pre-applications are due by 4:30 pm on Friday, November 22, 2024. If you have any problems getting the document from the link, or any questions please email UrbanConservation@iowaagriculture.gov. Urban Conservation team members are available to assist you through the pre-application process and they are listed in the linked document.

ISWEP News

IStorm 2024 Conference: Don't Forget to Register!

The 2024 IStorm Conference will be held on October 30-31 at the FFA Enrichment Center in Ankeny. We have a great program, tour, and reception lined up for you! There are still sponsorship opportunities.

ISWEP Welcomes New Professional Members

ISWEP is pleased to welcome two new Professional Members to our organization this year: Sherwood Design Engineers and ISG Engineering, both bringing valuable expertise to our growing network of stormwater professionals.

New Resource: Monthly Newsletter Articles for City Members

We're excited to announce a new addition to our resources: a monthly article designed for our city members to use in their own local publications. Each month, we'll provide a short, engaging article written for the general public, along with a complementary social media post. These pieces will focus on important stormwater management topics, offering practical advice and information to residents.

Members are welcome to adapt these articles to suit their specific needs and local context. These ready-made pieces aim to save you time while helping educate your residents about environmental issues. We also encourage you to submit ideas or specific needs for future articles – we're here to create content that serves your community best. Look for this new feature in each newsletter and feel free to incorporate it into your city's outreach efforts. (See below for the first version!)

Manage Leaves, Safeguard Streams

Fall leaves can be beautiful, but they pose a risk to our water systems if not managed properly. When leaves enter storm drains, they can clog pipes, cause street flooding, and contribute excess nutrients to our waterways as they decay. These issues not only affect our local infrastructure but can also harm aquatic ecosystems. Proper leaf management is crucial for protecting our water resources, ensuring public safety, and preventing property damage.

There are several effective ways to handle fall leaves responsibly. Never rake or blow leaves into streets, ditches, or storm drains. Instead, collect them in paper bags or bins for curbside yard debris pickup, if available in your area. Composting leaves at home is an excellent way to create nutrient-rich soil for your garden. You can create natural compost by layering shredded leaves and grass clippings in a garden bed or wooded area, allowing nature to break it down over winter into nutrient-rich organic matter. Alternatively, use a mulching lawnmower to recycle leaves and their nutrients directly into your lawn. By keeping sidewalks and streets clear of leaves, we ensure safety and proper drainage. With these simple steps, we can turn our fall leaves from a potential problem into a valuable resource.

Compliance Connections: Winter Button Up

It's getting to be that time of year when you need to start preparing your construction sites for winter. You can distribute this flyer to contractors in your area to get started on preparing for the cold weather.

ISWEP Member Conference Registration Scholarship

ISWEP members have the opportunity to apply for a scholarship to attend a national stormwater related conference of their choice every year. Scholarships up to $400 are awarded on a first come, first served basis until funds for the year have run out. Fill out and return this application if you have a conference you'd like to attend.

ISWEP Educational Resource Server

ISWEP Members have access to all educational resources through our website. The educational resource server can be accessed by following the link below and logging in. Resources from the most recent member meeting are found in the "+ Latest Educational Toolkit" folder. Please contact Loulou Dickey, ldickey@iowastormwater.org if you are experiencing any issues with the website or resource server.

ISWEP Swag Shop

Show your passion for the stormwater cause and your support for ISWEP with some swag. Our online shop has shirts, polos, sweatshirts, jackets, and more in men's and women's sizes and a variety of colors. Help us spread the word of ISWEP across the state! Check it out at the link below.

Items Available For Checkout