Severe flooding was highlighted in StarMetro’s Nov 9 report “Kepong residents want bigger retention pond”.
The Drainage and Irrigation Department (DID) has said physically widening the Benteng 1 Flood Retention Pond is nearly impossible due to surrounding private land and infrastructure, while deepening it is fraught with risks concerning the water table and water quality.
We must start treating this as a hydraulic engineering challenge. I propose a dual-pronged technical solution: implementing an active pump station integrated with a dedicated sediment forebay.
The fundamental flaw of the current 90,000cu m pond is its reliance on passive gravity drainage.
During intense monsoon rains, Sungai Jinjang swells, with the “backwater effect” preventing the pond from draining into the river, thus filling up and overflowing.
By installing a high-capacity, automated pump station, we can convert the pond into an “active detention” system.
Pumps will mechanically discharge water into the river regardless of level.
By drastically reducing emptying times, the pumps effectively increase the pond’s storage capacity.
A rapidly emptied pond provides a highly effective buffer during intense rainfall.
However, pumps are highly susceptible to silt and debris. This is where the second part of the solution comes in, based on standard Erosion and Sediment Control Plans (ESCP).
Current DID maintenance involves dredging the entire pond annually, which is inefficient and costly.
The pond must be retrofitted to include a separate, smaller sediment storage zone, or forebay, at the inlet.
Using data-driven hydrological modelling and Revised Universal Soil Loss Equation formulas, we can calculate exact sediment yields.
Heavy silt will drop out in this smaller zone before entering the main basin, protecting the pumps and ensuring DID only needs to dredge the forebay while preserving the main pond’s capacity.
DID must enforce upstream ESCP on all surrounding commercial and residential developments.
Silt fencing and check dams must be mandated to prevent soil from washing into the catchment area.
The pump station must have automatic backup generators to survive storms that knock out the power grid, alongside automated trash screens to manage Malaysia’s river debris.
By combining modern hydrological modelling and active pump infrastructure, DID and Kuala Lumpur City Hall can provide a permanent, resilient flood-mitigation system.
PHILLIP M RAJOO
Seremban
