Climate change and groundwater resources in Lao PDR

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1 Journal of Groundwater Science and Engineering Vol.5 Vol.4 No.1 No.2 Mar. Jun Climate change and groundwater resources in Lao PDR Khongsab Somphone 1*, OunakoneKone Xayviliya 1 1 Division of Groundwater, Department of Water Resources, MoNRE, Nahaidiew Road, Chanthabouly District, Vientiane Capital, Laos PDR. Abstract: The national economy of Lao PDR is highly dependent on water resources. Consequently, the sustainable management of groundwater and successful adaptations to future climate change are major concerns. Climate projections for Lao PDR predict increased rainfall and hot weather, with more intense rainfall events and more frequent and severe droughts and floods. Under climate change, reductions in the amount and quality of groundwater are two critical problems. Reductions of the groundwater level will restrict the access of local people to groundwater resources, thereby posing a threat to food security and livelihoods. Lao PDR suffers from a limited number of human resources with the requisite skills to perform groundwater investigations and provide sustainable management. For the successful implementation of groundwater management plans, limitations associated with funding and technology should be resolved via support from the government and international cooperation. Advanced action plans for capacity building and training courses should be established to strengthen administrative and individual capacities. Technical measures, such as groundwater monitoring, aquifer characterizations, and water treatment systems, should be implemented to manage future climate change and water resource security. Keywords: Groundwater; Water resource; Climate change; Lao PDR 1 Introduction 1.1 Status of groundwater in Lao PDR Climate and water resources Lao PDR is situated within the Indochinese Peninsula of Southeast Asia and borders Myanmar, Cambodia, China, Thailand, and Vietnam. Lao PDR has a tropical climate that is influenced by the southeast monsoon, which causes significant rainfall and high humidity. The climate is divided into the following two distinct seasons: A rainy season (or monsoon season) from May to mid-october and a dry season from mid-october to April. The average annual rainfall is approximately mm (Source Data: Water Balance Study in Laos, DMH, 2008). The average temperatures in the northern and eastern mountainous areas and the plateaus are 20 C, and * Corresponding author. SK.somphone@gmail.com C in the plains. Temperature ranges from highs of approximately 40 C along the Mekong in March and April to lows of 5 C or less in the uplands of Xiangkhoang and Phôngsali in January (Lao PDR, 2009). Table 1 Summary of the water supply of Lao PRD in terms of aerial coverage (Department of Statistics and the Center for Development and Environment in the MONRE 2010 census) Source Area (m 2 ) % Total Piped water % Borehole % Dug well % Surface water % Mountain spring % Rainwater % Other sources % Lao PDR has abundant surface water resources. Consequently, surface water serves as a major water supply source. However, an increased demand in the water supply and climate changes has led to increases in groundwater utilization in 53

2 Journal of Groundwater Science and Engineering Vol.4 Vol.5 No.2 No.1 Jun. Mar Lao PDR, particularly in the southern plains area, where surface water cannot meet the water demand. Table 1 summarizes the water supply situation in Lao PDR. A comparison of the surface water flow rates and estimated water demands of the area (primarily for irrigation) showed that the Sebanghieng and Sedone River Basins in the southern part of Lao PDR are expected to suffer from water shortage problems in the future if the current irrigation development level is maintained. 1.2 Climate change The climate change projections for Lao PDR are consistent with those of the wider Southeast Asia region. The Southeast Asia Science Technology and Environment Agency Regional Center (SEA START RC) has predicted the future climate changes of Southeast Asia and climate change vulnerability of the region using the Conformal Cubic Atmospheric Model (CCAM), which is a second-generation regional climate model developed by the CSIRO Division of Atmospheric Research in Australia (SEA START RC, 2006). The CCAM simulations were produced using an atmospheric CO 2 concentration of 360 ppm as the baseline representing present-day levels. For the future projections, the CO 2 concentrations were increased to 540 ppm (150% of current CO 2 concentration) and 720 ppm (200%). According to the climate change projection results with different atmospheric CO 2 concentration scenarios, Southeast Asia, including Lao PDR, is likely to experience increased rainfall and hot weather in the future. The predicted climate scenarios indicate that the region will tend to be slightly cooler under the increased CO 2 concentration of 540 ppm but warmer under the CO 2 concentration of 720 ppm. Slight decreases in air temperature under the 540 ppm CO 2 scenario could be related to the increased cloud cover in the region. The change in temperature under this set of climatic scenarios will be within the range of 1-2 o C, although the change in the number of annual hot and cool days will be prominent. Hot days, which are defined as the number of days with a maximum temperature over 33 C, will increase by 2-3 weeks, and the cool days, which are defined as days with a minimum temperature under 15 C, 54 will be reduced by 2-3 weeks throughout the region. Consequently, the summer time or dry season in the Mekong Region will be significantly longer in the future. The simulation results also revealed a trend of increasing precipitation throughout the region, especially in the eastern and southern part of Lao PDR (SEA START RC, 2006). The climate of Lao PDR is expected to be most affected by elevated CO 2 concentrations, especially during the wet season (March to August). The rainfall during the wet season would increase by 30% under both climate change scenarios (540 and 720 ppm) (Chinvanno S and Snidvongs A, 2005). Climate variability will also tend to be more extreme with increases in the range of precipitation between dry and wet years. Thus, more intense rainfall events and more frequent and severe droughts and floods will occur. 2 Climate changes and groundwater sustainability 2.1 Climate changes and hydrologic variability The hydrologic cycle represents the continuous movement of water between the atmosphere, the earth s surface (glaciers, snowpack, stream, wetlands and oceans) and soil and rock. The hydrologic cycle is driven by solar energy, which heats the earth s surface and causes water from the surface to evaporate, sublimate and transpire. Water moves from the atmosphere back to the earth s surface as either rain or snow. Any variations in climate have the potential to affect the water cycle, including runoff, evapotranspiration, groundwater recharge and discharge. SEA START RC estimated the impact of climate change on future hydrological regimes in the lower Mekong River region using the Variable Infiltration Capacity (VIC) hydrological model (LIANG X et al. 1994; SEA START RC, 2006). The model predicts that the rainfall intensity of the region would be increased while the length of the rainy season would remain the same, which will result in higher discharge in most of the Mekong River tributaries during the wet season. For the wet year scenario, almost every watershed will have

3 Journal of Groundwater Science and Engineering Vol.5 Vol.4 No.1 No.2 Mar. Jun higher discharge under the climate conditions at the CO 2 concentration of 540 ppm and increase further under the climate conditions at the CO 2 concentration of 720 ppm. In the dry season, however, many sub-basins will have slightly less water under the climate conditions at the CO 2 concentration of 540 ppm, although the discharge will increase under the climate conditions at the CO 2 concentration of 720 ppm. Future hydrological variability of the Mekong River Basin under the projected climate change has also been studied by the CSIRO (Eastham J et al. 2008). According to their analysis, all of the catchments in the Mekong River Basin will experience an increase in annual runoff by In the dry season, however, runoff reductions are likely to occur for 1-3 months, including in the MoungNouy and ThaNgon catchments of Lao PDR. The potential evaporation is also projected to increase by The projected increase in annual potential evaporation averaged across the basin ranges from 1.54 to 1.48 m, which is a change of 2%. 2.2 Impacts of climate change on groundwater Predicted sustainability of groundwater resources under climate change The term groundwater refers to water contained in soil and geologic formations that are fully saturated. The inflow of atmospheric and surface water to groundwater bodies can occur via several paths, including infiltration of rainfall and snowmelt and infiltration from stream channels, lakes and wetlands into the soil. The loss of groundwater to the atmosphere occurs through the process of evapotranspiration, which includes direct evaporation of shallow groundwater and transpiration by vegetation. Groundwater may flow into streams, springs, wetlands and oceans or may be pumped from wells for human use. The process by which water is lost from groundwater is called discharge. The difference between recharge and discharge determines the volume of water in groundwater storage. The impact of climate change on groundwater use is complicated. Any variations in climate have the potential to directly or indirectly affect groundwater recharge, discharge and quality. An example of a direct impact would be the variation in groundwater recharge because of changes in precipitation, runoff, and evapotranspiration. Sea water intrusions to coastal aquifers because of sea level rise can deteriorate the quality of coastal groundwater. Groundwater quantity and quality can also be affected by climate change and water usage patterns. Increased frequencies of severe droughts during the dry season will expand the exploitation of groundwater across the country, which could result in substantial reductions of groundwater resources. In central and southern areas of Lao PDR, including Khammoune, Savannakhet and Champasak, groundwater is an important water supply when the region experiences a reduction in the runoff rate and available surface water in the dry season. Moreover, with an increase in groundwater use, arsenic pollution is observed, especially in Champasak Province in southern Lao PDR. To sustainably manage groundwater resources to meet future water demands, an assessment of available groundwater must be performed. A reduction of groundwater during the dry season will decrease the flow rates of the major rivers of Lao PDR as well because the base flow accounts for a significant portion of river discharge during the dry season. 2.3 Impact of climate change on groundwater-dependent systems and sectors Reductions in groundwater amounts and quality are two critical problems under climate change, which are primarily observed in the following three aspects: Human community, agriculture and industry, and ecosystems Human communities The intensive use of groundwater will lead to the drying of shallow wells and decreases of groundwater levels below the bottom of hand pumps. Reductions in the groundwater level will restrict the access of local people to groundwater resources, thereby posing a threat to food security and livelihoods. 55

4 Journal of Groundwater Science and Engineering Vol.4 Vol.5 No.2 No.1 Jun. Mar Agriculture and industry The use of groundwater for irrigation may increase in the future to meet the water supply required for crop production in Lao PDR. Projected future climate change will cause a reduction of rain-fed rice cultivation in Lao PDR. The seasonal shift and change in precipitation patterns may change crop cycles and yields. A modelling study of crop yields by SEA STRAT RC (2006) predicted that the yield of rice production may be reduced by almost 10% in Lao PDR (Songkhone District, Savannakhet Province). Currently, irrigation schemes in Laos in which groundwater is used on a large scale have not been reported. Groundwater is often used for small homestead gardens by using hand-dug wells and boreholes. Pumping from surface streams is widely used for major irrigation projects. Many of these systems are old and have been performed poorly during periods of low river flows. Thus, an attempt to compare the costs of stream-supplied systems and groundwater-fed systems should be conducted. Information from the Khorat Plateau in Thailand would be a good reference because both the climate and the geology of this region are similar to those of central Lao PDR (e.g., in Savannakhet). Most industries in Lao PDR prefer locations next to major rivers and use surface water because of the lack of available hydrogeological information. The most notable example of the industrial use of groundwater in Lao PDR is the Lao Beverage Company, which produces Lao Beer and Tigerhead bottled water. The industrial plant in Vientiane initially used groundwater for manufacturing. The company attempted to improve the yield of groundwater wells via deepening, although during the process, the well encountered halite (rock salt), which subsequently ruined the existing wells. Because the failure of well development, the plant in Vientiane switched to surface water resources. This case strongly demonstrates the need for improved hydrogeological databases and groundwater flow system studies in Lao PDR Ecosystems The impact of climate change is likely to accentuate the competition between human and ecological water uses, particularly during periods 56 of protracted drought (Loáiciga H A, 2003). Environmental implications include the reduction or elimination of stream base flows and refugia for aquatic plants and animals, dieback of groundwater-dependent vegetation, and reduced water supplies for terrestrial fauna. In areas where salinization occurs, salt-sensitive species may be lost. Other sources of groundwater contamination may also adversely affect ecosystems. Climate change can lead to wetland drying and saline soils and the disappearance of spring, ponds and lakes (Bach H et al. 2014). A reduction in groundwater volumes and subsequent decreases in groundwater discharge into lakes, streams, and wetlands will exacerbate the drying process and threaten the variety of groundwater-dependent ecosystems. 3 Adaptations to climate change 3.1 Policies and management practices to protect water resources under climate change Because of the significance of climate change to water resources, the government of Lao PDR has implemented and improved the relevant policies, regulations, and laws to protect water resources. Based on the vision 2030 and strategy of water resources 2025 of Lao PDR, the department of water resources (DWR) of MoNRE (Ministry of Natural Resources and Environment), strategies and action plans are currently being improved. The water resource strategy for 2025 in Lao PDR consists of the following 12 programs: (1) Institutional strengthening and coordination; (2) legislation, plans and implementation; (3) river basin and sub-river basin management and planning; (4) groundwater management; (5) data and information management; (6) water allocation; (7) water quality monitoring, management and ecosystems protection; (8) wetland management; (9) flood and drought management; (10) water resource risk management and climate change adaptation; (11) sustainable IWRM (integrated water resource management) financing; and (12) awareness, participation and capacity building. Of these 12 programs, groundwater management (Program 4) aims to (1) formulate and implement regulations and groundwater manage-

5 Journal of Groundwater Science and Engineering Vol.5 Vol.4 No.1 No.2 Mar. Jun ment planning and (2) strengthen groundwater management capacities by promoting the involvement of all relevant sectors, public awareness and capacity building. The strategy and action plans regarding climate change adaptation are described in Program 10, which is the water resource risk management and climate change adaption program. At current level, the program mainly focuses on understanding the link between climate change and hydrological processes via data collection, planning and monitoring. Building the technical capacity of staff and promoting the public understanding of the risks, impacts and climate change adaptations for water resources are also the main objectives to be accomplished through the program. Lao PDR has updated its laws and regulations on water resource management. The new water resources law is being updated from the last version from The new version includes details on water resource management, including groundwater management. Parallel groundwater management regulations at the ministerial level have been drafted to ensure the implementation of productive groundwater management. Building the adaptive capacity for groundwater resources is important for the current conditions of Lao PDR. Currently, the Ground Water Division (GWD) of the DWR is responsible for groundwater management at the national level. The GWD and other relevant agencies of Lao PDR, however, do not have sufficient personnel with the requisite skills to perform groundwater investigations and sustainable management. The implementation of new action plans for capacity building and training courses will help the government to strengthen administrative and individual capacities. To implement advanced capacity building programs, limitations in funding and technology should be resolved via support from the government and international cooperation. 3.2 Technical measures to protect water resources under the climate change Managing groundwater recharge, storage, and discharge Understanding the processes of groundwater recharge, storage, and discharge is vital to establish proper management plans for groundwater. Aquifer systems are usually complex and show strong spatial and temporal variations. Without sufficient investigations of the aquifer environment, the sustainable management of groundwater cannot be achieved. The failed groundwater exploitation shown by the Lao Beverage Company is a good example that demonstrates the need for adequate investigations of the hydrogeological environments in Lao PDR. Climate change is a long-term process, and identifying the linkage between climate change and groundwater requires long investigations. The technical measures required to implement sustainable groundwater adaptation plans under climate change include enhanced monitoring technology, advanced aquifer characterization methods, and groundwater reservoir system construction Managed aquifer recharge Managed aquifer recharge (MAR) involves building infrastructure and/or modifying the landscape to intentionally enhance groundwater recharge. MAR is increasingly being considered as an option for improving the quality of water supplies (Gale I, 2005). MAR may be the most significant adaptation opportunity for many countries in Southeast Asia because it reduces the seasonal hydrological variability of the water resources. To successfully implement MAR, aquifer conditions must be appropriate for artificial recharge and suitable water sources must be available (e.g., excess wet season surface water flows or treated waste water). Sand dams or vegetation cover management may represent proper technical options for managing groundwater resources. Sand dams are produced by constructing a wall across a riverbed, which slows ephemeral water flows and allows coarser sediment to settle out and form a shallow artificial aquifer (Gale I, 2005). Adjusting vegetation cover or land use practices can optimize groundwater recharge and protect groundwater quality. Table 2 summarizes the potential technical options for water resource adaptations to climate change. 57

6 Journal of Groundwater Science and Engineering Vol.4 Vol.5 No.2 No.1 Jun. Mar Table 2 Technical options for water resource adaptations to climate change Adaptation option group Modify exposure to climate risk Adaptations (1) Manage or reduce the level of woody vegetation cover to optimize groundwater recharge (while protecting ecological values and avoiding erosion). (2) Managed aquifer recharge (MAR; or other forms of artificial rech-arge) in/near urban and rural settings to capture and use the following: - Urban storm water, including the use of detention ponds and infiltration systems; - Treated wastewater from industrial facilities and urban wastewater treatment plants; - Overland flows, such as dam reservoirs that are designed to leak and recharge water tables; - River flows (3) Adjust land management practices in groundwater recharge areas to maximize water table recharge and reduce overland flows, such as by maintaining ground cover, contouring banks, implementing keyline farming systems, etc. (4) River regulation to maintain flows over recharge beds for alluvial aquifers. 4 Challenges and problems The government of Lao PDR is focused on the current climate conditions and the associated impacts to groundwater and related economic development. Although the government has attempted to enhance its groundwater governance and polices to manage future climate changes, a number of challenges must be overcome to achieve this agenda. A lack of technical groundwater survey and management abilities represents the major issues restricting efficient groundwater management strategies. Limited data and funds are available to support national water management strategies, which represents a major challenge to be resolved. Collaboration and cooperation with national and international agencies and organizations would provide considerable opportunities to strengthen institutional and technical capacities for sustainable groundwater management in Lao PDR. The DWR has cooperated with agencies from Vietnam, China, Hungary, etc. and will extend these collaborations to other national and international agencies to achieve water resource security in the future. References Chinvanno S, Snidvongs A The pilot study of future climate change impact on water resource and rain-fed agriculture production case studies in Lao PDR and Thailand. Southeast Asia START RC technical report No. 13. Bangkok: Proceedings of the APN CAPABLE CB, 2004, 1. Eastham J, Mpelasoka F, et al Mekong river basin water resources assessment: Impacts of climate change. CRISO: Water for A Healthy Country National Research Flagship. Gale I Strategies for Managed Aquifer Recharge (MAR) in semi-arid areas. Paris: UNESCO IHP, 34. Lao PDR National adaptation programme of action to climate change. New York: UNDP, WREA, GEF, 106. Accessible at me/library/environment_energy/national_ad aptation_programme_climate_change.html LIANG X, Lettenmaier D P, et al A simple hydrologically based model of land surface water and energy fluxes for general circulation models. Journal of Geophysical Research, Atmospheres, 99(D7): Loáiciga H A Climate change and groundwater. Annals of the Association of American Geographers, 93(1): Bach H, Glennie P, et al Cooperation for water, energy and food security in transboundary basins under changing climate. Lao PDR: Mekong River Commission. SEA START RC (Southeast Asia STRAT Regional Center) Southeast Asia regional vulnerability to changing water resource and extreme hydrological events due to climate change. Bangkok: SEA START RC Technical Report No. 15,