DIS in the Mountains

Disconnected Impervious Surface

Innovative Stormwater Projects

Disconnected Impervious Surface, or DIS, is a simple, cost-effective technique that directs runoff to a flat vegetated area like a lawn or rain garden where it can soak into the ground.  This process, known as infiltration, recharges groundwater and filters out pollutants.  Keeping runoff on-site and out of the storm sewer also reduces the burden on stormwater infrastructure, lessens downstream flooding, and protects water quality.  

DIS in the Mountains is a pilot research project funded by the North Carolina Land and Water Fund to find innovative solutions to implementing DIS in steep slope areas.  RiverLink is partnering with Blue Earth Planning, Engineering & Design, Wildlands Engineering, and local homeowners to develop and install innovative DIS designs that are suited to steep slope conditions. The focus of the project will be residential sites in the Central Asheville Watershed that meet specific criteria, including having slopes greater than 8%.

Have Questions?

If you’d like to learn more about this project contact our Water Resources Manager, Renee Fortner at: renee@riverlink.org or (828) 252-8474 X 114

In Asheville, during a typical year, a 1,000 square foot roof would shed almost 30,000 gallons of rainwater.  Now, imagine the runoff from the roofs of thousands of homes, and we’re dealing with many millions of gallons of stormwater runoff (and pollutants) flowing into our streams every year.

Project Goals & Outcomes

  • Develop Disconnected Impervious Surface (DIS) designs that make DIS stormwater features a viable option for managing runoff in steep slope areas.
  • Work with homeowners to implement innovative DIS designs on residential properties in the Central Asheville Watershed.
  • Measure the effectiveness and homeowner acceptance of installed DIS designs.
  • Develop operation and maintenance manual for DIS stormwater features in mountain regions.
  • Conduct social research to better understand public perception of stormwater runoff and the perceived barriers and opportunities to managing stormwater. 
  • Use social research to design effective stormwater education material, including updates to the WaterRICH program.
  • Submit project findings to NCDEQ for possible expansion of DIS design criteria in the State BMP Design Manual. 

The project team will work with homeowners in the Central Asheville Watershed to develop innovative DIS designs that may include “earth works” such as berms & swales, terraces or spiral-shaped rain gardens. Once installed, the project team will monitor the innovative stormwater features for their effectiveness. Results from the pilot research project will help make DIS a cost effective solution to runoff in mountainous areas. 

In addition to the technical challenges, stormwater management also involves a number of social challenges and opportunities. In order to address social obstacles of implementing DIS on a wide scale, students from the Sustainability Studies Program at Lenoir-Rhyne University- Asheville will conduct social research using focus groups and surveys to assess residents’ awareness, understanding and perceived benefits and barriers of DIS. The social research findings will be used to develop educational materials on the negative impacts of stormwater runoff and emphasize DIS as a simple, cost-effective solution.