RAIN GARDEN DESIGN CONTEST 2013 MARCH 11 TH – 27 TH

WHAT IS A RAIN GARDEN? Water collects in rain gardens and is filtered through the plants and the soil  Reduces speed of water, lessening erosion damage that usually occurs from fast- moving runoff  Removes pollutants and excess nutrients from the water  Recharges groundwater with filtered water  Reduces polluted runoff water that enters waterways

WHY DO WE NEED A RAIN GARDEN?

FALLS LAKE CLEAN WATER REQUIREMENT EPA requirements for the Falls Lake Watershed:  20% reduction in total nitrogen by 2016  If the lake quality fails to improve by 2016, a $115 million upgrade of Raleigh’s E.M. Johnson Treatment Plant will be needed.  Other improvements may cost an additional $200 million.

OUR GOAL  Our proposed rain garden will remove ~ 1 lb of nitrogen per year, ~0.1 lb of phosphorous per year, and ~ 60lb of suspended solids per year  Engage local community to construct neighborhood and backyard rain gardens  Assist local homeowners with rain garden construction to expand the impact of the best management practice.

OUR CURRENT LOCATION Fig. 2 Heavy runoff from parking lot during rain event Fig.1 Current site: Royall Parking Lot

MAP OF WATER FLOW

PHOTOS OF WATER FLOW

PHOTO OF WATER FLOW

Impervious Area = 6390 square ft Pervious Area = 1278 square ft Total Drainage Area = 7668 square ft Imperv. Percentage in Watershed(%) = 83 Pervious Percentage in Watershed(%)=17 Rv (runoff coefficient) = 0.67 V(runoff volume) = 42 cubic ft Partial sun exposure Appropriate site; not wet/saturated 1.5 days after rainfall Soil Type: urban soil Rain Garden Size: 1024 square ft Peak storm water runoff  C (runoff coefficient) = 0.73  I (peak storm water runoff) = 7.2 in/hr  Q (peak flow) = cubic ft/second SITE MEASUREMENTS

TIMELINE + SUBMISSION Deadline: March 27 th, 9:00 AM If you have any questions, please contact