PERFORMANCE OF PEARL GRASS AS RIVER SILTATION CONTROL ASSOCIATED WITH RUNOFF

River pollution is majorly contributed by non-point source pollution which includes sediment-carried surface water runoff. Nowadays, man-made materials such as silt fence, jute fabric and wood excelsior which are used to control sediment carried-runoff are less preferred compared to natural vegetative system commonly called vegetative filter strips (VFS). This grass filter strips are more preferred because it is biologically natural, easier to maintain and cost effective. With the objective to study the effectiveness of vegetative filter strips to control sediment-carried surface water runoff, pearl grass (Axonopus compressus (dwarf)) was chosen as a subject in this study. The experiment was conducted in a 2m x 22m field erosion plot using 2m )4 2m filter strips. Samples of surface water runoff containing total suspended solid (TSS) were collected before and after the runoff water enters the pearl grass vegetative strips and water analysis on TSS was done using spectrophotometer. The plant leaves has the ability to absorb falling impact of rainfall, reduces the velocity of surface water runoff and thus filters and reduces the sediment carried by the water runoff downslope into open water bodies. In this study, mean total suspended solid (TSS) before VFS ranges from 2170 mg/L to 4575 mg/L while mean TSS after passing through VFS ranges from 1040 mg/L to 6463.33 mg/L. Pearl grass is 25.08% to 47.93% effective in reducing TSS and can be used as natural vegetative barrier for sediments entering open water bodies but due to morphological factor of pearl grass has thus limit the usage of pearl grass under certain circumstances.