ARE GOLF COURSES INFILTRATION SITES? SEASONAL DIFFERENCES IN RUNOFF SOURCES AND RATES IN A SMALL SUBURBAN WATERSHED

Stream restoration and other projects are usually initiated by observed problems such as high or flashy flood events, damage to infrastructure, bank erosion, or high sediment loads. Causes of these problems are often inferred from land-use or field observations. In this study, we examined precipitation-runoff relationships and storm hydrographs at 5 locations in a small headwater 2^nd order catchment. Headwater portions of the watershed are contained within a golf course, but the lower watershed is bisected by a major highway and has impervious cover from large buildings, parking lots and roadways. The monitoring was short-term (9 months) and designed to evaluate runoff response from the different portions of the catchment during both the cold season (including snowmelt) and the warm season. Major storms occurred in both seasons during the monitoring period. During the snowmelt season, saturated areas developed on the golf course. The headwater saturated areas and areas with low infiltration, such as adjacent to paved cart-paths, both generated overland flow that contributed to streamflow. The major roadway did not contribute to the main snowmelt peak because salting of the surface caused runoff during and shortly after snowfall, prior to the snowmelt peak. During snowmelt and spring storms, the golf course contributed both streamflow and sediment to the stream and hydrographs peaks did not build significantly downstream of the golf course. During summer storms, however, golf course runoff came from low infiltration areas, but not from headwater saturated areas and wetlands. The major roadway and impervious surfaces in the lower watershed contributed significant streamflow and discharge increased significantly downstream. Although intense summer storms generated the largest hydrograph response, significant erosion and sediment transport occurred during the spring snowmelt and storm events.