| Abstract: | ABSTRACT Urban storm water from a 1,067-acre drainage basin in Durham, N.C. was characterized to determine yield of pollutants. Population density averaged 9 persons per acre (ranging from <3 to 16). Annual BOD contribution attributable to surface wash during storms was determined to be approximately equal to contribution by its secondary wastewater treatment plant effluent. Total organic matter (COD) was estimated to exceed the amount in raw sanitary sewage from a residentially developed area of the same size. Mean basin yields (Ib/acre/day) were: BOD-0.23, COD-2.85, Total Solids-43.6, Volatile Total Solids-4.8, Total Phosphate-0.01 and Chloride-0.20 (as NaQ). The yield of lead presumed to originate from internal combustion engines operating on and near the basin was determined to be 0.006 Ib/acre/day. The concentration of total pesticides (Dieldrin; p,p'DDE; p,p-DDT; p,p'DDD and p,p'DDT) weighted for flow significance was estimated to be 1.2 parts per billion. The major long-term pollutional impact on a projected downstream reservoir was considered to be the fixed solids residue and long-term oxygen demand (COD). Intermittent release of other pollutants in slugs during runoff periods may be a significant factor in causing undesirable effects in streams draining urban areas. |
