Water and Adaptation Interventions in Central and West Asia
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Technical Assistance Consultant’s Report Project Number: 44066-012 (RETA 7532) June 2012 Regional Technical Assistance: Water and Adaptation Interventions in Central and West Asia Prepared by FCG Finnish Consulting Group Ltd In association with FutureWater and Finnish Meteorological Institute For Asian Development Bank This consultant’s report does not necessarily reflect the views of ADB or the Government concerned, and ADB and the Government cannot be held liable for its contents. (For project preparatory technical assistance: All the views expressed herein may not be incorporated into the proposed project’s design. FCG Finnish Consulting Group Ltd. in association with FINAL REPORT • FutureWater • Finnish Meteorological Institute Executive Summary Asian Development Bank Water and Adaptation Interventions in Central and West Asia TA 7532 June 2012 ADB / TA 7532 WATER AND ADAPTATION INTERVENTIONS IN CENTRAL AND WEST ASIA - SUMMARY OF RESULTS ABSTRACT. Central Asia is one of the regions suffering most from the impacts of climate change on its nature and economy. The report describes results from a study which developed models on the impacts of climate change on water resources and natural hazards in the Aral Sea Basin. The past climate was reconstructed using data from global climate databases compiled by using field and satellite observations. Several international climate change scenarios were used to model the changes of temperature, precipitation, glaciers and snow cover in the future up to 2050. The final goal of the project is to support Central Asian countries to prepare national strategies, policies and investment plans for climate resilience and adaptation. Modeling of future hydrology of the rivers helps to plan water management considering agriculture, hydropower, environment and municipal water services. The project made forecasts on climate change induced hazards as floods, droughts, mudflows, landslides and avalanches. The purpose was also to present proposals for adaptation interventions and capacity building in order to increase climate resilience in different regions. In 2050, river flows in the Amu Darya Basin will be 30 % less compared with the average flow of the past 10 years. Because the glaciers will diminish 45 - 60 %, spring flow remains high and late summer flow will radically decrease. This means floods in spring and droughts during hotter summer months and growing season. Thawing of permafrost in the higher mountains will generate landslides and mudflows. Annual total water demand in the Syr Darya Basin increases by 3.0 - 3.9 % in 2050. Annual unmet demand increases from 8.8% currently to 31.6 - 39.7% in 2050. Annual total water demand in the Amu Darya basin increases by 3.8 - 5.0 % in 2050. Annual unmet demand increases from 24.8 % currently to 45.8 - 54.5 % in 2050. Most cost-effective adaptation measures are (i) improving agricultural practice, (ii) deficit irrigation, (iii) increasing the reuse of water in agriculture, and (iv) the reduction of irrigated areas. Costs for closing the entire water gap (43,000 Mm3) are estimated at US$ 1,730 million per year in 2050. Closing the additional water shortage caused by climate change only (25,000 Mm3) will cost US$ 550 million per year in 2050. Climate Change Finnish Consulting Group is implementing an ADB financed Climate Change Adaptation project in five Central Asian countries together with Finnish Meteorological Institute and FutureWater from the Netherlands. The objective of the project is to generate models describing impacts of climate change on water resources and natural hazards in the Aral Sea Basin as well as to develop strategies for adaptation interventions. In the project, past climate was reconstructed using data from global climate databases compiled by using field and satellite observations. There are several international programs generating satellite-based climate data from the world and this data can be downloaded from Internet. Several international universities and research organizations have compiled complex climate change scenarios forecasting future climate (Fig. 1). Five different scenarios were used to model the changes of temperature, precipitation, glaciers and snow cover in the future up to 2050. Outputs will be applied to the development of climate resilience and risk management strategies at the regional, national, and river-basin levels. The activities of the project include: 1) Collection of existing field records and new satellite-based data on climate, hydrology and land-use in order to reconstruct the past and present situation; 2) Development of methodologies relating to downscaling of climate change scenarios, hydrological modeling, glacial melt, climate impact assessment, climate vulnerability and risk analysis; 3) Modeling of future hydrology of the rivers and identification of water management problems considering agriculture, hydropower, environment and municipal water services; 4) Generating forecasts on climate change induced hazards as floods, droughts, mudflows, landslides and avalanches; 5) Presenting proposals for adaptation interventions and capacity building in order to increase climate resilience in different regions; and 6) Development of capacity in the use and application of hydroclimatic models in the region. Figure 1. Climate warming of the study area (Aral Sea Basin) downscaled from five different climate change models (A1B emission scenario). Hydrologic Impacts of Climate Change The modeling results showed rather remarkable changes in the hydrology of the Aral Sea Basin. In the Tien Shan and Pamir Mountains the volume of glaciers will dramatically decrease as a result of climate warming. Until 2050, 45 - 60 % of the glacier cover has disappeared. During the 20 coming years, the runoff from melting glaciers will increase only in the high mountain areas, but the total discharge of the main rivers will decrease. The small ice caps especially from Tien Shan will disappear and also the melting water will be dramatically reduced (Fig. 2). In 2050, river flows in the Amu Darya Basin will be 30 % less compared with the average flow of the past 10 years (Figure 3 and 4). The situation will be worst in the late summer and early autumn when the river discharges are 45 % less than today. Without regulation capacity and reservoirs there will be shortage of irrigation water in the downstream areas. This fact should especially be considered in the management of the downstream part of the Amu Darya River and in the Karakum Canal. In the Syr Darya Basin (Figure 5 and 6), river flows will be 25 % less compared to the average of the past 10 years. For this basin, major flow reductions also occur in late summer and early autumn. The diminishing water resources together with the increasing temperatures in the plains create major risk for agricultural production. Figure 2. Also geomorphological evidence, moraines indicating bigger size of glaciers, shows that glaciers have already receded substantially during the last 150 years (KAZ/KGZ border, Almaty; Google Earth). Figure 3. Origin of water in the past ten years. In the Nurek reservoir in Amu Darya basin glacier melt is very important contributor to total runoff. Therefore, diminishing glaciers will cause major shortage of water in the downstream areas. Figure 4. Origin and volume of water in the past and future in the Nurek reservoir in Amu Darya basin. Reducing glaciers and glacier melt have major effect on the total volume of discharges in the river. Figure 5. In the Toktogul reservoir in Syr Darya basin, glacier melt is less important. Snow melt and rain-runoff are the most important contributors to total runoff. Figure 6. Origin and volume of water in the past and future in the Toktogul reservoir in Syr Darya basin. Impacts on Water Resources Management People living in the upper stretches of rivers will certainly continue to construct reservoirs to ensure water allocation to irrigated fields there. This may lead to a situation, where farming in the downstream areas becomes difficult. The situation can clearly be seen from the inflow figures of the reservoirs in the both basins (Fig. 7). Figure 7. Accelerated decrease of discharges to the Nurek reservoir (Tajikistan, Amu Darya Basin) and linear decrease in Toktogul reservoir (Kyrgyzstan, Syr Darya Basin) 2001 – 2050 modeled using five different climate change scenarios [1]. The models also predict possible annual variations between different years based on the reference period 2001 - 2010. We analyzed the past and present annual hydrology and modeled the impact of climate change on the rivers and generated hydrographs comparing the present discharges with the predicted future situation (Figure 8). The most significant changes can be seen in the rivers which are flowing out from areas dominated by glaciers. Figure 8. Annual hydrographs for the Nurek reservoir (Tajikistan, Amu Darya Basin) and Toktogul reservoir (Kyrgyzstan, Syr Darya Basin) in the past (field observations) and in the future modeled using five different climate change scenarios [1]. In January-May the discharges (Q) will remain similar as today, but major reduction will take place in June- November discharges because of diminishing glaciers. Because the glaciers will diminish, their run-off regulation capacity will be lost. In general, the models do not predict higher discharges for future spring times, but sudden changes in temperature and rainfall may cause abrupt run-off peaks. Also in the future, major snowstorms and fast snow melting may easily generate major floods in spring time. Impacts on Mountain Environment Because of the rapid melting and retreat of the of the margin of glaciers, new proglacial lakes will be generated. It is common that ice-cored moraines create dams in front of fast receding valley glaciers (Fig. 9). Such lakes may have extensive amount of water and whenever the dam collapses, a catastrophic flood may occur. Flood protection interventions are needed in areas identified to be vulnerable to flood damages. Figure 9. A catastrophic flood may occur when an ice-cored dam of a proglacial lake will collapse (Petrov Lake, Kyrgyzstan. Google Earth). The snowline will raise 200 - 300 meters in average until 2050 (Fig.