Formation of human-induced lakes in Uzbekistan: The Aydar-arnasay lakes system case study
The Aydar-Arnasay lakes system (AALS) is situated in the south-eastern part of Uzbekistan on the territory of Navoi and Dzhizak provinces. In the north it is bordered by the Kyzyl-Kum desert whereas in the south by the foothills of the North-Nuratau mountains and extensive irrigated areas of the Golodnaya steppe in the east. The Aydar-Arnasay lakes system includes lakes Aydarkul, Tuzkan, Arnasay or East Arnasay lakes and surrounding desert areas. The total length east to west of these lakes is 300 km and its north to south width varies from 30 to 50 km. The water level of the lakes system is about 240-242 m, water-surface area more than 3700 square km and volume about 44,3 cubic km.
The current development of the Aydar-Arnasay lakes system (AALS), which is one of the remarkable examples of the human-induced ecosystems, depends on numerous political and environmental factors. On the one hand, the political tensions and disagreements between Central Asian republics alter the implementation of the coordinated water policy in terms of agreed water discharges to the Aydar-Arnasay lakes. The republics concerned, i.e. Uzbekistan, Kazakhstan and Kyrgyzstan, are focused on their own national interests and are not trying to consult the neighbors’ water needs. On the other hand, forecasting change of the regional climate has an uncertain influence on these lakes. It is unclear, how the assumed climate change will impact the hydrological features of the AALS, such as volume water level, thermal regime and others in future.
Therefore, the future fate of this system is completely undetermined. Besides, fisheries situated in these lakes, wetlands ecosystems designated as a Ramsar site and recreational activity and tourism directly depend on the Aydar-Arnasay lakes. In accordance with a level of regional cooperation between republics and significance of climate change the Aydar-Arnasay lakes can have various development scenarios in future. These scenarios will take into consideration the different situations in terms of water discharges coming to these lakes and the general water policy in the republics concerned.
The following objectives were pursued in order to achieve the main goal of the project:
- to describe the overall review of the Aydar-Arnasay lakes system (AALS), including preconditions of the lakes’ formation, hydrological research conducted, current ecological conditions, and evolution of fish farming;
- to analyze contemporary ICT as a tool for assisting environmental science and consider the successful worldwide examples and best practices of ICT application;
- to analyze practical use of methods such as environmental modeling, scenario approach and remote sensing for data analysis;
- to identify the main scientific methods for data collection and analysis which can contribute to the goal achievement;
- to examine the past of the Aydar-Arnasay lakes system in terms of historical stages of the lakes’ formation and change dynamics of the AALS water level and volume;
- to examine the present development of the Aydar-Arnasay lakes from the socio-economic and environmental aspects;
- to elaborate possible water management for the analyzing future development trends of the Aydar-Arnasay lakes;
- to create the model of the Aydar-Arnasay lakes system for testing the elaborated scenarios using STELLA software;
- to simulate model for each water management scenario;
- to interpret the results obtained from the model simulation for achieving the main goal.
In order to achieve the main goal of the project, a complex of different research methods was applied to ensure that this study meets its objectives. The main methods used for data collection are literature review, unstructured interviews, and GIS data mining. Among the main methods for data analysis, the following have been applied:scenario approach for elaboration of the water management scenarios; environmental modeling assisted by the STELLA software; GIS methods using the Arcview program; Remote Sensing using the MultiSpec program.
Based on the analysis of the archival materials and national scientific books and reports historical stages of the Aydar-Arnasay lakes formation have been identified. Besides, a set of maps illustrating the lakes’ evolution has been made by the author. Practical exercise aimed to analyze the change dynamics of the AALS water-surface area in 1969-2009 has been accomplished by the author using GIS technologies.
Examination of the present state of the Aydar-Arnasay lakes, including analysis of the fisheries situated in these lakes, wetlands designated as a Ramsar site and recreational activity has been carried out.
The most important objectives established for the main goal achievement have been executed. Namely, a set of various water management scenarios based on level of regional cooperation and level of climatic changes have been elaborated. They are “Ready for Challenge”, “Fall Behind”, “Promising Future”, and “Business as Usual”. Then, the Chardara – Aydar-Arnasay lakes model aimed to test these scenarios has been created using the STELLA software. Finally, the model created has been simulated for each water management scenario and results illustrating the change of the AALS volume in 2010-2040 have been obtained.
In the process of the interpreting results and their discussion the following conclusions have been found:
Scenario I “Ready for challenge” has two alternative water management sub-scenarios, which are:
1. Sub-scenario Ia which is focused on the full cooperation between Uzbekistan, Kazakhstan, and Kyrgyzstan; it has been concluded that this sub-scenario is quite idealistic for the future development of the Aydar-Arnasay lakes; the main reason of that is impossibility to have such high cooperation between countries as it is assumed in the scenario; besides, consulting interests which is more probable for the AALS future development;
2.Sub-scenario Ib which is based on consulting interests; it has been found that this scenario is more probable for the AALS future development comparing with the previous one. Meeting the water needs of the neighbors will be taken into account and the AALS maintenance will be included into the national water policies of Uzbekistan’s neighbors. Moreover, it is highly probably that climate changes will have some impact on the hydrological conditions of the lakes;
Scenario II “Fall behind” is one of most plausible and realistic for the future development because of a high probability of low regional cooperation between countries in future and assumed change the regional climate which will lead to aggravation of the balanced development of the whole lakes system;
Scenario III “Promising Future” is the most idealized for the AALS future development and could not be brought into real life because of the impossibility to achieve such high regional cooperation between countries;
Scenario IV “Business as Usual” is the most realistic and feasible for the future development of these lakes; the prime features of this scenario are illustrative for the current state of the Aydar-Arnasay lakes condition; it is possible that these same AALS development trends will be observed over the next thirty years.