Tran Thi Hong Ngoc^1,, Mark Honti²

Aquaculture in the Long Xuyen Quadrangle-An Giang (LXQ-AG), has drawn a lot of interest due to the favourable conditions of the area and therefore it has experienced significant development by local people. Products from aquaculture are crucial in the healthy nutrition and they possess a great export value, improving the living standard of local people. However, aquaculture may be unsustainable due to many reasons, such as eliminating significant water resources via pollution. In the LXQ-AG, aquaculture competes for the vital, limited water resources with irrigation that supports rice cultivation. This competition has not received proper attention yet. Therefore, the total water demand for the aquaculture sector should be calculated to ensure the sustainability and potential development of both aquaculture and irrigation. The open-water evaporation model of Penman was used to calculate evaporation losses from ponds, various assumptions were made to estimate the water required to flush the ponds. The result shows that the total water demand was 2,188 million m³ yr^-1 in 2015. It is estimated that in 2020, aquacultural water demand will be 18,140 million m³ yr^-1, an increase by a factor of 8.29. The main reason for this rise is that the local managers expect the catfish farming area to increase by 80%, and farm operators are expected to apply the “VietGAP standards”. The study showed that the inevitable evaporative losses are negligible in the total water demand of aquacultural ponds. Therefore, it is straightforward to reduce the future water demand by adopting water-saving operating procedures in the dry season.

Vietnam, An Giang Province, evapotranspiration, aquaculture, Penman equation