Technical Report No. 71
BASELINE QUALITY DATA FOR KALIHI STREAM
Gordon K. Matsushita, Reginald H.F. Young
June 1973
ABSTRACT
The purpose of this study was to determine the changes in stream water quality related to variations in land use patterns and to establish some baseline data for assessing the Hawaii State Water Quality Standards for surface waters. Effects on water quality were determined by collecting and analyzing water samples taken from four sites that were located along the course of Kalihi Stream from October 1971 to August 1972. The sites were selected within different land use areas along the stream to account for any variation in contribution from undeveloped and developed lands. Water samples were analyzed for physical, chemical, bacteriological parameters as well as pesticides and heavy metals. Rainfall for the drainage area and stream discharges were also recorded during the study period.
The stream water quality for wet and dry weather flows were found to compare favorably with other Hawaiian investigators and were in the same order of magnitude as those in the U.S. and other countries. Pollution loads were also calculated on a lbs/acre/day basis and these results compared favorably with U.S. and Hawaiian investigators. The parameter concentrations and pollutional loads were found to increase in a downstream direction as incremental and individual subbasin drainage areas increased in development, land use activity, population density and housing density. The water quality results established baseline data for Kalihi Stream and were compared with the State Water Quality Standards. It was found that fecal and total coliform densities exceeded Class 2 Standards during dry and wet weather conditions and that the nutrient standards for Class A waters were also exceeded during dry and wet weather. There was no significant pesticide contribution to pollution of Kalihi Stream as all results were in the low ppt range.