Assessment of surface water resources in Bay Nui region, An Giang province in the context of climate change

Abstract

The objective of this study is to assess surface water resources from small reservoirs in the Bay Nui region, An Giang province. To achieve the above objective, firstly, to assess the current state and potential of surface water resources from the small reservoirs in the study area according to the climate change scenarios for the period 2030s and 2050s; to estimate water demands of different water sectors; thereby to assess water supply capacity from the reservoirs and to propose water use alteratives. The results show that the total water capacity of existing reservoirs is 2.61×10⁶m³, and under planning reservoirs is 6.36×10⁶m³. The estimated water demand for domestic and agricultural activities (cultivation - one rice crop and one crop, and animal husbandry) is very large and the total current capacity can meet only 3.28% of the water demand for six months of dry season. Water demand under climate change scenarios (RCP2.6, RCP4.5, and RCP8.5) in the period of 2030s and 2050s according to alternative 1 (PA1) (01 rice crop and 01 vegetable crop) is 151.96×10⁶m³ to 158.19×10⁶m³, respectively; PA2 (perennial fruit tree) is 150.33×10⁶m³ to 150.40×10⁶m³; and PA3 (perennial fruit tree - application of irrigation for water saving) is 56.61×10⁶m³ to 61.43 ×10⁶m³. The total existing reservoir water has capable of supplying water according to PA1 is 7.53% to 7.77%; PA2 reaches from 6.22% to 6.58%; and PA3 reaches from 14.81% to 16.27%. Therefore, it is necessary to have a plan to change the structure of plants and animals accordingly. In addition, to adopt reasonable water storage solutions, it is necessary to make the investment into distributed and small and medium reservoirs to supply for agricultural production.