Nutrient Concentration Distribution in Sediment and Overlying Water at Bukit Merah Reservoir, Perak

Abstract

Bukit Merah Reservoir (BMR) is the oldest reservoir in Malaysia constructed to supply irrigation water to the Kerian Irrigation Scheme. Depletion of storage capacity due to sedimentation process is the most concerning issue of the reservoir recently. Sediment analysis is also very important when monitoring the substances that appear in the reservoir water. Environmental toxins, like heavy metals and hydrophobic organic components, as well as nutrients such as nitrogen and phosphorus are readily bond to the particulate matter. Factors in the reservoir that affect the particulate matter will aid the distribution of contaminants in the sediments. The contaminants in the sediments could have higher concentrations compared to those found in the overlying water. This means that the sediment plays an important role in the cycling of nutrients and distribution of contaminants in the ecosystem. The objectives of this research are to determine the relationship of nutrient and heavy metal content for sediment and overlying water. Nutrient profile information is provided from sediment sample analysis. Based on the data from the horizontal distribution of surface sediment phosphorus in BMR, it was apparent that the highest concentration occurred in the reservoir inlet from Sungai Kurau catchment area. Phosphorus and nitrogen in BMR have a similar trend of decreasing concentration from upstream to downstream. The phosphorus and nitrogen concentrations of surface sediment were in fact significantly correlated with phosphorus and nitrogen concentrations of surface water because of the high value of determination of correlation (R2). As a conclusion, the deposition of sediments was found to bring along external nutrients. Variability of phosphorus and nitrogen concentrations in the sediment directly affects the quality of water which is very important for irrigation and domestic uses.