Our objective is twofold
- To assess how runoff in the Amu Darya and Syr Darya Rivers will change in the future under a range of climate change scenarios.
- To assist water resource managers with adaption strategies to changing runoff, we explore the impact of adopting efficient irrigation systems and changing crop patterns.
To address the first objective, we will develop a new glacio-hydrological model by coupling a glacier flow model to the Dynamic ﬂuxEs and ConnectIvity for Predictions of HydRology (DECIPHeR). Tuyuksu glacier, in the Kazakh part of the Tien Shan, will be used as a case study to evaluate the performance of the new model. This benchmark glacier has the longest continuous measurements of surface mass balance in central Asia, extending from the 1956 to the present day. Discharge rates from the Little Almatinka River downstream of the glacier will be used to validate the simulated runoff. Meteorological observations, retreat rates and discharge measurements downstream of the glacier will be provided by the Institute of Geography, Al-Farabi Kazakh National University, Kazakhstan.
The model will be used to simulate discharge in the Amu Darya and Syr Darya for the future using PRECIS regional climate modelling data for Central Asia provided by collaborators at Nazarbayev University, Kazakhstan. We also apply the model to other glacier fed rivers systems in Central Asia such as the Chon Kemin and Ili Rivers. The Chon Kemin is a tributary of the important Chu River which provides Kyrgyzstan’s capital Bishkek with freshwater. The Ili River which runs from north western China into Kazakhstan terminates at Lake Balkhash. This is the 15th largest lake in the world and an important resource for Kazakhstan’s water supply, including the population of the capital Almaty.
We use the future runoff projections to test whether there is sufficient river discharge to sustain current irrigation practices and at what point in the future adaptation measures need to be considered. This leads to the second objective which is to test adaption options to reduced runoff. Several strategies to meet the water demand deficit are explored. These include reducing the irrigated area and increasing reservoir capacity to store rain water in the winter. We test the impact of replacing open channel irrigation with subsurface drip fed irrigation or overhead sprinkler irrigation. Reducing the water demand by planting different crops is also tested. For example, replacing cotton, which is water intensive to grow, with crops that are important for food security such as wheat, rice and legumes.