Prairie and Turfgrass buffer strips modify water infiltration and leachate resulting from impervious surface runoff
Concerns over NO3–N concentrations in drinking water and potential subsurface transport of P to surface waters are driving legislation on precautionary N and P application restrictions on turfgrass areas and in recommendations for vegetative plantings within urban environments. Two plant communities and three impervious:pervious surface ratios were examined for effects on leachate water quantity and quality over a 3-yr period. A Kentucky bluegrass blend (Poa pratensis L.) and a mixed forb and grass prairie were monitored for 3 yr for total leachate volumes, total dissolved N (TDN) loading, and soluble PO4–P loading. Both types of vegetation provided similar annual groundwater recharge rates. Annual TDN losses from fertilized turf and unfertilized prairie were similar during and after establishment, with postestablishment losses averaging 3.6 and 2.2 kg ha–1, respectively. Mean annual soluble PO4–P losses postestablishment were 0.6 and 0.7 kg ha–1 for fertilized turf and unfertilized prairie, respectively. When compared with the absence of a buffer area, pervious surfaces at least one-half the size of impervious surfaces resulted in at least a 50% reduction in drainage water volumes. Fertilized turfgrass and unfertilized prairie vegetation provided similar groundwater protection and recharge abilities, and both resulted in some natural biogeochemical nutrient cycling.