Surface Wash: The Dominant Geomorphic Process in the Surviving Rainforest of Singapore

Severe wet spells and vulnerability of urban slopes: case of Singapore

“…1 a Rezaur et al (2002Rezaur et al ( , 2003; b Rahman (1992); c Chatterjea (1989aChatterjea ( , 1994; d Author-current field data, obtained from 50 samples at each site; e Chatterjea (1989bChatterjea ( , 1991 safety. Data from various sources are looked at in detail with a view to establishing and emphasizing the relationship between rainfall events and slope failures, as observed by many researchers on this topic.…”

“…These records are for the surface soils at 0-28 cm depths. The suction recovery may be attributed to root action and also to the generally high clay content of all Singapore soils as well as the high evaporation-related moisture loss from the caked surfaces soon after the onset of the dry days (Chatterjea 1989b;Gasmo et al 1999;Pitts and Cy 1987;Rezaur et al 2003). Negative pore-water pressure, u w , or matric suction when referenced to the pore-air pressure, u a , (u a -u w ), plays a significant role in stability of slopes (Lim et al 1996).…”

Effectiveness of Grass Cover in Reducing Risk of Sediment Generation on Urban Slopes: An Example From Singapore

“…Urban development of any area involves a transient period of rapid construction work when extensive areas are cleared of vegetation cover, the underlying soil is exposed, and the ground is kept bare and vulnerable to the erosive forces of rainfall. Although the scale of the development work determines the degree of such disruption, accelerated erosion during this period is a common occurrence (Douglas, 1978;Leigh, 1982;Gupta, 1982;Poon, 1984;Chatterjea, 1989a). The results of the sharp rise in sediment generation can be seen in the extensive gully development on the bare slopes at the construction sites (Leigh, 198 1;Douglas, 1983;Chatterjea, 1989a) as well as in the sedimentation patterns downstream from the area of sediment generation.…”

“…Although the scale of the development work determines the degree of such disruption, accelerated erosion during this period is a common occurrence (Douglas, 1978;Leigh, 1982;Gupta, 1982;Poon, 1984;Chatterjea, 1989a). The results of the sharp rise in sediment generation can be seen in the extensive gully development on the bare slopes at the construction sites (Leigh, 198 1;Douglas, 1983;Chatterjea, 1989a) as well as in the sedimentation patterns downstream from the area of sediment generation. Extension of sediment plumes from river mouths onto the coastal waters of Singapore have been reported and these have been ascribed to the catchment areas undergoing construction work or other types of anthropogenic changes (Chatterjea, 1989a;Nichol et al, 1990).…”

“…The results of the sharp rise in sediment generation can be seen in the extensive gully development on the bare slopes at the construction sites (Leigh, 198 1;Douglas, 1983;Chatterjea, 1989a) as well as in the sedimentation patterns downstream from the area of sediment generation. Extension of sediment plumes from river mouths onto the coastal waters of Singapore have been reported and these have been ascribed to the catchment areas undergoing construction work or other types of anthropogenic changes (Chatterjea, 1989a;Nichol et al, 1990). However, this accelerated erosion during the construction period is short-lived and rates are reduced close to natural undisturbed levels as urban development projects are completed (Gupta, 1982).…”