In place since 1990, the National Pollutant Discharge Elimination System (NPDES) Stormwater Program focuses on maintaining clean storm sewer systems along with managing water requirements for industrial and construction-related activities. Since then, further enhancements by state governments and local municipalities have taken matters a step further with added regulations to enhance the state of stormwater management.
By enforcing these policies, governments are protecting city water sources from polluted water runoff due to poorly designed landscapes and impervious surfaces, while often having the added effect of reducing potable water usage in situations where it's not necessary, like irrigation and flushing toilets.
The three mini-case studies below are excellent examples of how projects around the country are responding to local requirements.
Multi-Family Development in Portland, Oregon
One of many stormwater projects associated with the City of Portland, Headwaters at Tryon Creek worked especially hard to incorporate a range of stormwater management techniques during project design and construction in order to stay on top of local regulations. Completed in 2008, this multi-family development is still a great example of innovative use of many stormwater management techniques.
The stormwater work on this site began during site excavation, when more than 2,200 tons of contaminated soil were discovered, removed and replaced from the job site, allowing the area to start fresh with clean soil and gravel.
One of the most significant aspects of this project was the daylighting of Tryon Creek. The creek, which had previously been routed underground, was brought back to an above ground channel, which was then used to connect local wetlands with a newly developed rain garden. This project made natural habitats available for local animals. In addition, swales were thoughtfully placed around buildings to collect water runoff from roofs. The swales were positioned to feed into the on-site rain garden. Together, the rain garden, creek and wetlands act as a natural solution for stormwater management.
Further efforts incorporated two eco-roofs, which grow herbs, protect roofs from deterioration and act as a natural water filter for rain, so that roof run-offs that splash into swales below are pre-filtered and highly safe for fish and wildlife in the creek/wetland areas.
The development also received new permeable parking lots, which allow rainwater to saturate into the ground and prevent flooding, as well as flow-through planters to provide decorative runoff management. For these successes, Headwaters at Tryon Creek received the American Society of Landscape Architects (ASLA) Oregon Honor Award in 2008.
Community Park in Baltimore, Maryland
After the Baltimore City Department of Housing and Community Development demolished 18 homes that were part of a rowhouse community, the Parks & People Foundation moved in to enhance the ultra-urban area and create a green space for public use, which would be known as the New Broadway East Community Park.
As is common in areas that have supported residential living for a long time, soil at the site was found to be highly compacted and severely lacking in stormwater retention ability. The Parks & People Foundation de-compacted the soil, then landscaped the area with permeable concrete and pavers and native plants and trees.
The New Broadway East Community Park was funded by a $200,000 state grant, as well as additional funds provided by private companies and local groups. Following completion in 2013, the park received the 2013 Smart, green & Growing Award for Innovations in Stormwater Management.
Public University in Minneapolis, Minnesota
The University of Minnesota is reducing the demands on municipal water supplies by introducing rainwater storage cisterns, which it says "can help cities meet increasingly stringent MS-4 stormwater rules while reducing the load on existing storm water conveyances."
The project was initiated in part due to the state's stormwater management requirements, and also in observance of its recent success with a similar project, which involved installing a 35,000-gallon cistern near a residence hall, allowing resident students to use roof runoff for flushing toilets and doing laundry.
This new project will use another underground cistern to harvest and retain rainwater for use in the university's evaporative chiller system. Currently, U of M's evaporative chiller system uses potable water supplied by ground water wells. Due to the water's high mineral content, it can only be cycled through the system three to four times before the system becomes endangered for mineral buildup. At this point, the water is flushed out and replaced. The school has reported that it uses about 100 million gallons of potable water per year purely for its evaporative chiller system.
By using harvested rainwater, which is naturally distilled and low in chemicals and acids, U of M will save money on water costs while also preserving the potable water supply for use in drinking fountains and taps. The project is funded by a $300,000 university-sourced grant, and is halfway through a two-year timeline with an estimated completion date in June of 2016.
These projects demonstrate how it’s possible to meet local requirements, saving money and even receiving national recognition along the way. To learn more, download our article on the impacts of development on the hydrologic cycle and learn how long-term stormwater management can be achieved.