River water bad, dam water dropping

Going with the flow: Air Selangor workers using excavators to block the flow of water from the contaminated Sg Buah into Sg Semenyih.

PETALING JAYA: While the authorities are grappling to contain the contamination that has shut down water treatment plants three times this month, they also have another problem on their hands.

The water level at the Sungai Selangor dam that supplies 60% of Selangor and Putrajaya’s treated water is dropping fast and is now close to the 40% level which triggered water rationing two years ago.

The dam is now at 43.29%, dropping more than 6% in the past 15 days alone, according to data from the Selangor Water Management Authority (Luas).

On March 2, 2014, water rationing was imposed in the Klang Valley and Selangor on March 2 to May 1 after the water level dipped below 40%.

The critical level for the dam is 30%, and the current reading is far below the 82.58% recorded exactly a year ago.

“There’s a risk of rationing if the level continues to drop,” said Asso­ciation of Water and Energy Research Malaysia president S. Piarapakaran.

He cited two possible reasons for the rapid drop.

The first is the lower than average rainfall over the Sungai Selangor dam’s catchment area.

The second is that a higher than normal rate of water is being released from the dam, to meet demand by treatment plants after the river contamination elsewhere.

Piarapakaran said the Sungai Selangor Phase 1 treatment plant was producing 10% more treated water than usual, while the Sungai Selangor Phase 3 plant was producing 30% more.

“If we don’t get lots of rain soon, the Klang Valley could end up with a situation similar to Mersing,” he added, referring to the Johor town which was hit by a six-month long scheduled water supply exercise which only ended yesterday.

MetMalaysia brought no immediate cheer.

A spokesman said the inter monsoon period this month would see less rainfall.

In October last year, there was 100mm to 250mm below average rainfall, according to the department’s website.

“However, the situation is expected to improve with more rains from early next month due to the arrival of the north-east monsoon,” said the spokesman.

The north-east monsoon brings heavy rain not just to the east coast of Peninsular Malaysia.

West coast states, including Selangor, can also get as much as 20% to 60% above average rainfall.