KUCHING: The flash floods that hit southern Sarawak earlier this year were due to drainage issues, it has been confirmed.
In a series of presentation by Local Government Minister Senator Datuk Dr Sim Kui Hian said floods in February and mid May were storm water related – not river flooding as was the case in 2009, 2004, 2003 and 1963.
The “executive summary of Kuching flood mitigation update” dated June 19, showed the state capital at risks of floods from four factors. The probability of further storm water flooding was rated as “high” and “medium” impact.
The second risk factor was river flooding, with the probability set at “medium” but its impact was “high”.
Dam failure (referring to the water supply reservoir of Bengoh) as a cause of floods was rated as “very low” but with an impact of “very high”.
The probability of floods caused by tidal breach was rated at “very low” and impact at “high”. The tidal breach refers to the Kuching barrage.
“The floods in February were caused by storm waters. The city’s drainage was only designed for 150-180mm of rain,” he said.
Back then, areas in Kuching that have almost never flooded before – such as the Sarawak General Hospital and a fire rescue station in the inner city – were submerged under water. The state police headquarters was affected too.
Data from Feb 27 and 28 showed more than 300mm of rainfall was recorded.
The abnormally heavy rainfall in southern Sarawak in February caused at least 194 landslides and embankment failures, forcing some 20,000 to be evacuated in three episodes of floods.
In the slides that Dr Sim shared, a five-prong solution was suggested. These included prevention and avoidance, placing emphasis on better land development regulation and source control.
Under protection and mitigation, it called for more flood risks management assets like flood channel improvement, river control mechanisms and reservoir impounding. Asset maintenance was also highlighted as key.
Public safety awareness campaigns was emphasised under preparedness, including authorities’ ability to spread forecasting information and warnings.
The risk management called for better emergency actions during and post disasters. Frequent reviews of flooding events, “learn lessons” and “updates on flood boundary maps” were suggested.
Just after the May 7 Sarawak Election, flash floods hit the capital after what seemed like relatively short spells of heavy rain. Back then, the newly appointed Local Government Minister issued a statement saying an extra RM70mil would be sought to improve drainage in the inner city.
The amount was based on estimates for projects drawn up by the a new flood prevention committee formed after February’s natural disasters.
For years, a flood diversion channel that will cost billions of ringgit had also been talked about.