Implications of climate change and drought on water requirements in a semi-mountainous region of the Vietnamese Mekong Delta

As the backbone of Vietnam's economy, the country has recently established a number of policies for promoting and investing in smart agriculture in the Mekong Delta, the country's largest agricultural hub, to foster overall socio-economic development. However, water remains a critical constraint for crop production, with progress being hindered by water scarcity and quality issues, and compounded by socio-economic transformation and climate change. Considering these challenges, this study used the CROPWAT model and a wide spectrum of climate change scenarios to investigate future total water demands in the 2030s and 2050s as well as drought levels in two underdeveloped semi-mountainous reservoir catchments, i.e., O Ta Soc and O Tuk Sa in An Giang province. The results suggest that the usable storage capacity of the O Ta Soc reservoir will increase to 650,000 m³ to meet water supply demands under all climate change scenarios and the medium-term, moderate drought conditions. The useable storage capacity of the O Tuk Sa reservoir will also be increased to 880,000 m³ and the irrigation area would see a marked 70% reduction compared to its design irrigation. Under these circumstances, the O Tuk Sa reservoir will continue to supply water under all climate change scenarios and medium-term droughts. As a core element for strategic planning and to ensure efficient management of water resources, the results highlight the importance of estimating potential runoff and rainfall in semi-mountainous reservoir catchments under various drought conditions in order to propose the suitable expansion of the useable water storage capacities.

A study on assessing the urban growth, population, and water resources of Bodrum Peninsula, Turkey

In recent years, it has been difficult to establish a supply-demand balance between urban growth, increasing population, and existing water resources in many countries. In this study, the Bodrum Peninsula, which is an important tourism center for Turkey, was examined in terms of the relationship between the urban growth of the peninsula, population projections, the need for drinking and potable water, and the availability of the existing water resources. Using the Geographic Information System, it has been determined that the urban growth of the peninsula increased by 11.36% between 1985 and 2010. Urban growth is mostly concentrated in the coastal areas where 2 houses are densely built. The population is expected to increase approximately six times between 2010 and 2060. The amount of drinking and potable water required according to the population projection is 12.38, 26.50, 69.12, and 109.50 hm³/year for 2010, 2030, 2050, and 2060 respectively. The existing water resources of the peninsula will be able to meet the requirements until 2030. In order to meet the water needs of the peninsula until 2055, the Bozalan and Gökçeler dams located nearby as well as the Namnam dam located at mid-range to the peninsular should be built. It is not possible to meet the water needs of the peninsula in 2060 with just the near and medium distance water resources. However, by supplying water from the Akköprü dam located at a further distance, it is possible that 2060 water needs can be met.

Adapting water resources systems to climate change in tropical areas: Ecuadorian coast

Climate change is expected to increase rainfall and temperature in the tropical areas of the Ecuadorian coast. The increase in temperature will also increase evapotranspiration therefore, future water balance on Ecuadorian coast will have a slight variation. Changes in precipitation patterns and evapotranspiration will produce an increase in the water requirements for current crops, so an imbalance in the water resources systems between natural resources and water demands is expected. This study presents water resources management as an adaptation measure to climate change for reducing vulnerability in tropical areas. Twelve bias-corrected climate projections are used, from: two AR5 General Circulation Models (GCMs), two Representative Concentration Pathways, 4.5-8.5 scenarios, and three time periods, short-term (2010-2039), medium-term (2040-2069) and long-term (2070-2099). These data were incorporated into the Lumped Témez Hydrological Model. Climate change scenarios predict for the long-term period both a mean rainfall and temperature increases up to 22%-2.8 °C, respectively. Besides, the potential evapotranspiration will increase until 12% by Penman-Monteith method and 60% by Thornthwaite method. Therefore, natural water resources will finally have an increase of 19% [8-30%]. Additionally, water requirements for crops will increase around 4% and 45%. As this research shows, in tropical regions, currently viable water resources systems could become unsustainable under climate change scenarios. To guarantee the water supply in the future additional measures are required as reservoir operation rules and irrigation efficiency improvement of system from 0.43 to 0.65, which it involves improving the distribution and application system. In study area future irrigation areas have been estimated for 13,268 ha, which under climate change scenarios is unsustainable, only 11,500 ha could be expanded with a very high irrigation efficiency of 0.73. Therefore, in tropical areas the effect of climate change on expansion projects for irrigated areas should be considered to ensure the functioning systems.