System Dynamics Modeling of Water Level Variations of Lake Issyk-Kul, Kyrgyzstan

Yilinuer Alifujiang,Alim Samat,Jilili Abuduwaili,Long Ma,Michael Groll

doi:10.3390/w9120989

Abstract

Lake Issyk-Kul is an important endorheic lake in arid Central Asia. Climate change, anthropogenic water consumption and a complex basin hydrology with interlocked driving forces have led to a high variability of the water balance and an overall trend of decreasing lake water levels. The main objective of this study was to investigate these main driving forces and their interactions with the lake’s water level. Hydro-meteorological and socioeconomic data from 1980 to 2012 were used for a dynamic simulation model, based on the system dynamics (SD) method. After the model calibration and validation with historical data, the model provides accurate simulation results of the water level of Lake Issyk-Kul. The main factors impacting the lake’s water level were evaluated via sensitivity analysis and water resource scenarios. Results based on the sensitivity analysis indicated that socio-hydrologic factors had different influences on the lake water level change, with the main influence coming from the water inflow dynamic, namely, the increasing and decreasing water withdrawal from lake tributaries. Land use changes, population increase, and water demand decrease were also important factors for the lake water level variations. Results of four scenario analyses demonstrated that changes in the water cycle components as evaporation and precipitation and the variability of river runoff into the lake are essential parameters for the dynamic of the lake water level. In the future, this SD model can help to better manage basins with water availability uncertainties and can guide policymakers to take necessary measures to restore lake basin ecosystems.

Highlights

Water is considered the most precious natural resource [1], and its availability is directly threatened by human activities [2]
The year 2012 was characterized by another small decrease with a water level of 1606.99 m at the end of that year (+0.81 m in 14 years; +5.79 cm/year)
The highest water level during the study period was detected in 2011 (1607.02 m), and the lowest water level was recorded in 1998 (1606.18 m), while the years from 1998 up to 2011 registered an increasing lake level amplitude of 0.84 m, indicating a high temporal dynamic. These fluctuations of the Issyk-Kul water level are the result of the climate change and the anthropogenic water use in the catchment

Summary

Introduction

Water is considered the most precious natural resource [1], and its availability is directly threatened by human activities [2]. Combined with projected population growth, expanding irrigation schemes, increased evapotranspiration rates, and the growing water demand for domestic and industrial purposes, these climatic changes will have a significant impact on the water balance in the near future [5]. This thematic issue is serious in Central Asia [6], a region characterized by intense water-related issues and heavily affected by the climate change [7,8,9]. It is evident that in many lake catchments the agriculture development is associated with increasing water withdrawal from lake tributaries, which causes serious lake water level drops [14,15,16]

Objectives

Results

Conclusion