Continuous and sustainable water supply

Abas Abdullah and Kevin Starling, Malay mail Online

Selangor implemented water rationing in March and April this year due to trending of low water levels in the Sungai Selangor Dam (SSD) and Sungai Tinggi Dam (STD).

It started with 200 million litres per day (mld) under Phase 1, followed by 500mld and 1000mld under Phase 2 and 3 respectively. For Cheras and Kuala Langat areas, the water treatment plants (WTPs) were also affected by the presence of high ammonia content in the raw water during times of low flow, which led to the water rationing exercise.

The releasing of water from dams, particularly for water supply purposes, by operators are implemented based on dam designer’s guidelines, which is a tool to manage the water resources in an efficient and effective manner. However, these rules may change, if one resource is substitutable with other resources or substantial rainfall is recorded in the upper or low catchment areas results in minimum release of water from the dam.

In March, SSD recorded 46.31 per cent (106.52 million cubic meter, mcm) storage whilst STD recorded 76.76  per cent (87.89 mcm) storage. Selangor had lifted water rationing effective 30 April 2014 when both dams and lower catchment areas had good rainfall.

The main reason Selangor implemented rationing during that period was mainly to create longer sustainability of resources in both dams.

It should be noted that water rationing was not only implemented in Selangor, but other states such as parts of Johor, parts of Perak and parts of Negri Sembilan, which had similar scenarios and mitigation measures.

Before Selangor lifted the water rationing, the State explored risk mitigation measures by exploring alternative resources to substitute the shortfall release or to cut back release from the dams.

These measures were primarily to ensure that the State can provide continuous sustainable water supply until the next wet season forecasted to be in mid-Oct 2014.

Two key tasks had been adopted to explore the alternative water supply from the Bestari Jaya ponds and intensive cloud seeding in the catchment areas based on the advice of the Bureau of Royal Thai Rain Making Agency.

As at 31 July 2014, the SSD was at 33.46 per cent storage capacity (equivalent to 76.96 mcm), whilst the STD was at 47.29 per cent storage capacity (equivalent to 54.26 mcm). The storage levels presented in LUAS’ website was referring to ACTIVE storage or net usable water in the dams.

Based on the operating guidelines for SSD and STD, on 31 July 2014, there should have been a cut back in production for SSP1, SSP2, SSP3 and Rasa WTPs from an average production per day of 2805mld to 2200mld. However, the shortfall or deficit of 605mld was mitigated through the Bestari Jaya pond pumping and natural low base flow in Sungai Selangor.

Without the raw water supply from these ponds, there would have been a water rationing or hydrological risk.

The State Government through the various agencies, namely UPEN, LUAS, JPS and Kumpulan Semesta, are targeting to deliver 800mld or higher volume from these ponds in order to allow further cut back of water release from the dams.

These initiatives are well-supported by SPAN and the Ministry of Energy, Green Technology and Water.

With the substitution of dam release as an alternative water source, the trigger point of rationing may vary downwards to a 30 per cent storage level or lower, unlike in March and April when there was no alternative plan. However, if the situation does not improve, the state may have to impose water rationing as a last resort.

The State Government is constantly on alert mode and working closely with SPAN to impose a stringent rule on water operators with regards to water rationing.

Nevertheless, the State efforts did not stop here. Recently, the Federal Government agreed to assist the State in the cloud seeding operations together with LUAS.

Two airplanes were employed in each operation (one each from TUDM and LUAS) to enhance and improve the probability of rain-making that was highly dependable on the presence of suitable clouds.

However, even with 2 airplanes in use in each operation of the cloud seeding, it was considered insignificant as compared to Thailand’s 25 airplanes and 5 airplanes for each operation.

In order to achieve higher success rate, more frequent flights were implemented during the day and night as well as increasing the number of airplanes in operations. In July, 12 trips of cloud seeding operations were implemented.

The unfavourable weather conditions of the tropical storms in Filipina and Taiwan caused low pressure and movement of clouds towards both countries. Hence, there was hardly any cloud in Malaysia and Selangor.

The other key focus areas included ensuring that the treated water supply from WTPs meets the national drinking standard. In addition to laboratory tests conducted by water operators on the treated water quality, the Ministry of Health (MOH) also monitors and regularly conducts tests at the WTPs, balancing reservoirs and distribution networks.

For sources from Bestari Jaya ponds, water samplings had been undertaken on a weekly basis by MOH regardless of the water level in the ponds.

In addition to the above efforts, the State and KDEB have also initiated discussion with the World Health Organisation (WHO) representatives in Kuala Lumpur to undertake an independent forensic study on water from ex-mining pools.

However, WHO was unable to undertake the task due to limited resources and expertise but referred the state and KDEB to various independent consultants. Amongst the consultants, CH2MHILL, an independent water consultant agreed to undertake an independent and objective assessment of the drinking water safety and public health risk from supplementing the Sungai Selangor flows with water stored in offline former mining pools.

The study will cover the whole spectrum from the mining pools to Sungai Selangor as well as the water treatment plants, thus, giving value added deliverables to the State in developing Bestari Jaya ponds into Hybrid Off River Augmentation System 3000 (HORAS 3000). In spite of the high costs involved, the study will still be undertaken in the interest of ensuring water safety to consumers.

Another critical aspect of the water industry in Selangor is an on-going awareness programme to educate consumers on saving water consumption, which will be immediately implemented by the new consolidated State-owned water company upon completion of the water restructuring exercise.

Selangor State Water Task Force Committee