Thailand is facing challenges with managing water quality in many reservoirs across the country due to pressure from agricultural, domestic, and industrial pollution, coupled with urbanisation and climate change.
The Australian Water Partnership’s Australia-Mekong Water Facility is supporting exchange of knowledge, expertise and standard methodologies of reservoir quality management between Australian partners (led by Griffith University) and the Thailand Royal Irrigation Department (RID) water quality team.
Traditionally, RID supplied and managed water for irrigation, however, in recent decades many local and small business activities, including fish farming, recreational fishing and swimming have become reliant on reservoirs. The multifunctional use of reservoirs has meant there is a need to improve water quality management and procedures.
The most immediate issue for the management of RID reservoirs is the control of aquatic weeds. In the north-east and north-west of the country many reservoirs have become blocked by uncontrolled weed growth. The reservoirs are no longer able to be accessed by local communities who rely on them for food and travel.
In Thailand, the expansion of agricultural areas surrounding reservoirs acts as a non-point source pollution through improper application of fertilisers and pesticides, along with disposal of animal manure, leading to eutrophication of the reservoirs. Some of the problems due to elevated nutrient levels in reservoirs include the rapid spread of aquatic weeds such as Salvina molesta. This plant, native to south-eastern Brazil, has been spread widely throughout the world over the past several decades and can reduce the flow capacity of irrigation canals thereby reducing the availability of water to the farmer’s field.
Aquatic weeds can interfere with aquaculture by assimilating large quantities of nutrients from the water reducing their availability for planktonic algae, and reduce oxygen levels. Experts from Griffith University, CSIRO and Chulalongkorn University have been working with the RID to develop a manual, including implementation strategies and guidelines for reservoir water quality management, monitoring and eutrophication prevention and mitigation in Thailand.
“This project will allow greater utilisation of the available water across many industries, from large irrigators, right down to the local villages accessing food and water,” said Griffith University Project Leader, Adjunct Associate Professor Kelvin O’Halloran.
In April 2022, Associate Professor O’Halloran and Dr Edoardo Bertone facilitated an intensive workshop with the RID water quality team in Thailand. The workshop was followed by monthly meetings reviewing the progress of projects arising from the workshop, and other potential steps that could be taken to improve water quality.
In November and December 2022 representatives from RID, the Royal Agricultural Department, and the Public Works Authority along with senior academics from Chulalongkorn University will visit Australia to exchange knowledge on water resources and management.
A central part of the delegation program will be site visits to regional authorities in south-east Queensland who regularly manage aquatic weeds using a mixture of biological and chemical control. In addition, the delegation will visit CSIRO facilities to observe the most up-to-date knowledge of biological control. This visit will be followed by a final workshop to finalise the manual for adoption to improve reservoir water quality management in Thailand.