Hydrology, water quality and trophic state of Pergau Reservoir, Kelantan, Malaysia

Abstract

ABSTRACT To acquire baseline data for a remote Pergau Hydroelectric Power Plant reservoir, a hydrological and water quality examination of feeder rivers and reservoir water was conducted in 2013. The water balance of the reservoir was determined, and gauging and sampling were carried out in dry and wet periods. Dilution gauging was used to estimate the feeder river discharge. The total water flow into the reservoir increases nearly fivefold between the dry and wet seasons, while river discharge increases two to fivefold. All of the river intakes had Class 1 NWQS water quality. The lake’s water quality was Class 1 up to the top 3 meters, but below that, at some places, the water quality deteriorated to Class II. In the dry season, the trophic status of Pergau Reservoir is eutrophic as measured by TP (59.21) and chlorophyll-a (52.36) and the TSI (SD) was 53.93 Eutrophication occurrences will cause serious limitations in water use applicability. This research contributes to the biogeographical and limnological understanding of the Pergau catchment, as well as laying the groundwork for more sophisticated hydro-ecological investigations. Anthropogenic activities, together with run-off from agricultural operations and the presence of algae, are some of the sources of contamination noted in the study. Stricter legislation, stricter enforcement of current standards, matching of non-technical and techno-social remedial actions, and education are among the recommendations made for the Pergau Reservoir’s protection.