WRRCPR No.94-06 Microbiological Assessment of Kaelepulu Stream and the Impact of Discharge in Kailua Bay (KB-3)

Abstract

Kaelepulu Pond is an inland brackish water pond (20 ppt salinity) which is under tidal influence and is fed by rainfall. Water from this pond flows via canals and streams (Kaelepulu Stream) for approximately 2 miles through a residential community (Kailua) and discharges into the ocean at Kailua Beach, the most popular beach on the windward side of Oahu, Hawaii. Water in the Kaelepulu pond and stream system has been classified for recreational use and must meet the State standard of 200 fecal coliform/100 ml. A sewage pumping station located next to this stream has been documented to occasionally discharge untreated sewage into the stream. The bacterial quality of the water in this stream system has been previously determined to be poor, and citizens of this community have concluded that the sewage from the pumping station is responsible for the poor water quality. The objective of this study was to determine the sources of fecal indicator bacteria entering the Kaelepulu Stream system and to assess the impact of this stream on the water quality of water at Kailua Beach. Water from throughout the stream system, soil, and duck feces were analyzed for indicator bacteria (fecal coliform, enterococci, E. coli, and C. perfringens). Storm drains and tributary streams (especially during rainfall, soil, and duck feces) were the major sources of fecal indicator bacteria Kaelepulu Stream. Analysis of stream water samples showed the, of the three recreational water quality standards, the enterococci standard was exceeded most frequently, followed by the E. coli and the fecal coliform standard.