KUCHING: Sarawak’s plans to intensify development in Upper Rajang needs to be balanced with biodiversity conservation in an integrated manner to ensure sustainability of the area for posterity.
WWF-Malaysia hopes that environmental protection will be a key component in the development masterplan to be carried out by the new Upper Rajang Development Agency (URDA), as announced in the press recently.
“It is imperative that any development in the Upper Rajang River Basin be done in a sustainable manner, integrating considerations for the area’s importance for water supply and biodiversity conservation, and coordinating all actions in the basin in an integrated manner,” said WWF-Malaysia Sarawak Programme Leader Dr Jason Hon.
WWF-Malaysia is currently working with some government agencies and the private sector to promote an Integrated Watershed Management plan for the Rajang Basin, he said in a statement responding to government’s plans to intensify development in Upper Rajang that was announced last week.
Dr Hon explained that this is crucial as land use and human activities in the basin can affect both the rivers and water quality there, as well as to downstream areas.
Conversion of forest landscapes into other land uses for example, can result in an increase in runoff and sediment flows into rivers and the existing dam reservoirs, he said.
“This will reduce the capacity of the reservoirs to store water over time and ultimately reduce its energy generation capacity. Forests play an important role in regulating the hydrological cycle and thus, the water balance in an area,” he said.
“Management of the area from a basin perspective and adopting an integrated river basin management approach is highly encouraged to optimize benefits so that the environment which produces the ecosystem services we depend on is also protected, and social and economic benefits can be better optimized in the long term,” he added.
Dr Hon lauded the state government’s efforts in recognising Upper Rajang area as an important biodiversity area and encouraging Kapit to become a biodiversity research centre.
This will contribute to better understanding of the biodiversity and ecosystems in the area and ensure that they will be well managed and protected, he said.
The Rajang River basin covers an area of 5 million ha. Its major tributaries are Balui River, Baleh River and Katibas River. The headwaters drain from the Iran and Hose mountains in the upper Rajang in the central region, within the boundaries of Sarawak’s Heart of Borneo.
This area holds great values for biodiversity and ecosystem services. Rivers in the headwater areas are habitats for Sarawak’s iconic freshwater fish – the Empurau (Tor tambroides) and Semah (Tor douronensis) – and contain forest habitats with a wealth of species still largely unstudied.
In November 2015, Forest Department Sarawak, Universiti Malaysia Sarawak, Sarawak Energy Berhad and WWF-Malaysia conducted a joint scientific expedition in Upper Baleh. Findings showed that a lot could still be learned from this area, including potential new species and distribution records for flora and fauna.
Apart from biodiversity, one of the most important values of the Upper Rajang River Basin is the water supply it provides to sustain the existing Sarawak’s Corridor of Renewable Energy (SCORE) project and more importantly, the water needs of people in the Basin for both upstream and downstream.
The Kapit gazetted water catchment covers approximately 3.5 million ha of this area and is the biggest for Sarawak.
Within it are the Bakun and Murum dams, which have a total catchment of about 1.5 million ha in the upper basin area.
The Upper Rajang River Basin contributes about 50,000 million cubic metres of mean annual runoff at Belaga alone, providing important water supply for all human and industry activities downstream.
