Civil Engineering

Canopies of forested and agricultural ecosystems can significantly alter rainfall patterns into separate stemflow
and throughfall areas. These two areas often have also different organic matter contents and soil compaction
properties, and hence also soil hydraulic properties, thus causing further differences in the local infiltration
rates close to and away fromtrees. In this studywe analyzed possible differences in the unsaturated soil hydraulic
properties of the stemflow and throughfall areas below an oil palmtree. Tension disc infiltrometer experiments
were carried out underneath the canopy and in the interspace area of an oil palm tree plantation at successive
tensions of 5, 2, and 0 cm. Soil hydraulic properties were estimated inversely from the measured data using
the HYDRUS-2D/3D software package. Four van Genuchten soil hydraulic parameters (i.e., the residual water
content, θr, the shape factors α and n, and the saturated hydraulic conductivity, Ks) were optimized. Saturated
water contents, θs, were fixed at their laboratory-measured values. Initial estimates of the optimized parameters
were set according to Wooding's solution, which ensured rapid convergence of the inverse solution. The
stemflow and throughfall regions exhibited contrasting hydraulic properties as indicated by the estimated
hydraulic parameters. Values of θs, α, n and Ks for the stemflow area were all found to be higher as compared
to those of the throughfall area. The inverse solution using tension disc infiltrometer data proved to be very useful
for rapid characterization of hydraulic properties of soil under the oil palm trees.

The possible occurrence of stratification was assessed in Sembrong reservoir located in
Kluang, Johor, Peninsular Malaysia. It is a man-made reservoir. Profile samplings were
conducted at eight points. Water samples at each point were collected at discrete depth
intervals of 1m. In situ measurement of Temperature , pH, Conductivity and Oxidation
Reduction Potential (ORP) were carried out using Hydrolab DSX5. Water samples were
analysed in lab for Fe, Al and Mn using Inductively Coupled Plasma Optical Emission
Spectroscopy (ICP-OES).The results show that pH, temperature and ORP tend to decrease
after 3m depth. On the other hand, concentrations of Fe, Mn and Al slightly increased with
depth as a result of reduction process. This phenomenon confirms the occurrence of reservoir
stratification

For the past decades, the number of research on Non Point Source (NPS) pollution has increased due to its nature being the major source of pollution to water degradation around the world. The study of NPS in Malaysia is scarce especially in agricultural areas. This research aims to provide quality and quantity of runoff pollutant loadings from an agricultural farm at a plot scale. Two plots were constructed at different land use (fruit orchard and vegetable farm). Tipping bucket flow gauges were installed at the end of each slope to measure runoff volume and collect water sample. The water samples were collected over a period of three months, immediately following rainfall events. Nine water parameter (Nitrite, Nitrate, Ammonia, Total Nitrogen, Phosphate, Total Phosphorus, Chemical Oxygen Demand, Total Suspended Solid, pH) analyses were conducted by using the DR5000 UV-Spectrometer. Result indicated that Total Suspended Solid (TSS) from fruit orchard is much higher while the nutrien...