Nutrient and fecal coliform discharge from coastal North Carolina golf courses

Water quality investigations were conducted at five golf courses in southea stern North Carolina to determine levels of pollutants contributed by the c ourses to adjacent coastal streams. In general, nitrate levels were greater in streams leaving the courses compared with streams entering the courses, but concentrations varied considerably among courses. Ammonium concentrati ons increased in passage through most of the courses. Orthophosphate concen trations were elevated on midcourse sites on two courses, but were low in t he outflow water except at one course. The golf courses studied were not si gnificant sources of fecal coliform bacteria to nearby waterways; in fact, passage through some courses served to reduce coliform loads entering from upstream suburbs. Recent rainfall and fertilization application influenced outfall nitrate concentrations only at some courses. Landscape management p ractices appeared to play a critical role in determining nutrient concentra tions in the outfall and at midcourse sites. Nutrient addition bioassay exp eriments conducted in one of the coastal creeks receiving golf course efflu eut demonstrated that nutrient concentrations as low as 50 to 100 mu g nitr ate N L-1 were capable of causing significant phytoplankton biomass increas es. Nitrate levels in the outflow streams were at or above concentrations c ausing significant increases in phytoplankton biomass in our bioassay exper iments. These coastal creeks host spring and summer algal blooms; thus, som e golf course discharge nutrient concentrations are at levels great enough to contribute to eutrophication problems in estuarine waters. Vegetated buf fer zones, wet detention ponds, and wooded wetland areas led to considerabl y lower nutrient output than sites lacking such management practices and sh ould be used whenever possible to protect nutrient-sensitive receiving wate rs.