The water resources potential of the urban estuarine complex comprised of the Saugus and Pines Rivers and Lynn Harbor, Massachusetts, was evaluated. Impairment of recreational usage is caused by eutrophication resulting from raw waste discharges and nutrient reserves in sediments. A laboratory study of the growth of marine algae, Ulva latissima, made in flowing sea water, indicates an optimum growth at nitrogen-phosphorous ratios of between 40 and 60 to 1, at a phosphate concentration of 120 micrograms per liter. Average values for nutrients in eutrophic areas were 268 micrograms/liter total orthophosphate and 0.513 mg/1 nitrates. Sediments from these areas averaged 5.98% volatile solids, 0.532 mg/1 extracted orthophosphates, and 2.177 mg/1 total Kjeldahl nitrogen. In contrast, oligotrophic areas, including parts of the Pines River, had average values of 164 micrograms/1 total orthophosphate, 0.175 mg/1 nitrates, 0.79% volatile solids, 0.349 mg/1 extracted orthophosphates and 0.294 mg/1 total Kjeldahl nitrogen. (WRSIC abstract)