Quality of storm-water runoff, Mililani Town, Oahu, Hawaii, 1980-84

Water-Resources Investigations Report 85-4265




Storm water runoff and rainfall data were collected at two urban sites in Mililani Town, Oahu, Hawaii between September 1980 and August 1984. The data included results from analyses of 300 samples of storm water runoff. Turbidity, suspended solids, Kjeldahl nitrogen, and phosphorus concentrations exceeded the State of Hawaii Department of Health 's streamwater standards in more than 50% of the samples. Mercury, lead, and fecal coliform bacteria levels exceeded the U.S. EPA 's recommended criteria for either freshwater aquatic life or shellfish harvesting waters in more than half the samples. Other constituents exceeding State or federal standards in at least one sample included pH, cadmium, nitrate plus nitrite, iron, alkalinity, manganese, chromium, copper, zinc, and the pesticides heptachlor , lindane, and melathion. Runoff correlated well with rainfall in both basins. Antecedent rainfall conditions and rainfall intensity had little effect on the quality of runoff. No statistically significant relationships were found between quantity of runoff and concentration of water quality constituents. A ' first flush ' effect was observed for chemical oxygen demand, suspended solids, lead, nitrate plus nitrite, fecal coliform bacteria, dissolved solids, and mercury. There were significant (alpha = 0.05) differences between the two basins for values of discharge, turbidity, specific conductance, chemical oxygen demand, suspended solids, nitrate plus nitrite, phosphorus, lead, dissolved solids, and mercury. The larger basin had higher median and maximum values, and wider ranges of values. (Author 's abstract)

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Quality of storm-water runoff, Mililani Town, Oahu, Hawaii, 1980-84
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Water-Resources Investigations Report
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U.S. Geological Survey,
vii, 64 p. :ill., map ;28 cm.