HR: 0800h
AN: H51B-0442    [Abstracts]
TI: Temporal and Spatial Variations in Total Suspended and Dissolved Solids in the Upper Part of Manoa Stream, Hawaii
AU: Fares, A
AF: Watershed Hydrology Laboratory, Department of Natural Resources and Environmental Management, 1910 East-West Road, Honolulu, HI 96822, United States
AU: * Augustijn, D
EM: d.c.m.augustijn@utwente.nl
AF: Water Engineering and Management, University of Twente, P.O. Box 217, Enschede, 7500 AE, Netherlands
AU: Tran, N
AF: Watershed Hydrology Laboratory, Department of Natural Resources and Environmental Management, 1910 East-West Road, Honolulu, HI 96822, United States
AB: Hawaiian watersheds are small and steep and receive large amounts of rainfall with a strongly non-uniform distribution. Therefore streams are flashy in nature which has its effect on water quality. Total suspended solids (TSS) and total dissolved solids (TDS) were used to investigate the variability in water quality parameters in the upper part of Manoa Stream in Honolulu. With a few interruptions, water samples were taken on a daily basis between October 2005 and June 2006. TSS and TDS varied from nearly nothing to 724 and 302 mg/l, respectively. TSS and TDS did not show a correlation with discharge. Data from a separate study by US Geological Survey, performed between 1991 and 2001 for the same stream, showed values for TSS up to 1320 mg/l for discharges higher than measured in this study. For the high discharges of the USGS data TSS showed an increasing and TDS a decreasing trend. It is concluded that the rainfall leading to extreme discharges (> 5 m3/s) causes more land and channel erosion and dilutes the solutes in base flow. At lower, more common discharges the system is supply-limited and affected by local conditions. The results of this study stresses the necessity of recognizing the variability in small streams for setting up a monitoring strategy, building a model to describe water quality or extrapolating water quality data to annual loads.
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2007 Fall Meeting