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Geographic and temporal scale

To begin with, let us start with a description of the geographic and temporal scale of the Aydar-Arnasay lakes model. The present model is one-dimensional, i.e. it includes only one space dimension. The model considers the Chardara reservoir situated in the middle stream of the Syrdarya River and the Aydar-Arnasay lakes system fed by the Chardara water (Figure 25).

Figure 25. Geographical location of the simulated area²⁰

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The quantitative value of the model’s parameters is basically determined by availability of reliable data. The most precise data for the model’s parameters have been found for 2000- 2008. These data have been obtained from the current field research, scientific calculations, experts’ estimations and national reports. Therefore, all quantitative data which we will put in the model will be average mean calculated for 2000-2008.
Simulation of the developed water management scenarios using the model will be conducted for the period 2010-2040. Consequently, the future development of the Aydar- Arnasay lakes will be analyzed for this period of time.

²⁰ The present map has been made by the author using the Arcview program

2. Basic assumptions

The Chardara- AALS model is based upon the following basic assumptions:

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  The model assumes that the most important input parameters for the Aydar-Arnasay lakes system are water discharges from the Chardara reservoir, inflow from drainage network, and inflow from the rainfall;
  
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  Water losses from the Aydar-Arnasay lakes basically occur only through the outflow from evaporation and percolation;
  
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  The model takes into consideration changes on average annual temperature based on historical records. It has been concluded that average annual temperature made up 13- 16 C degrees during 1970-2010. Random coefficient composes about 0-0,6 C degrees;
  
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  At present, the annual average temperature is 14,8 ºC and evaporation is 2,7 km³ (EDB 2009);
  
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  The model supposes that the amount of precipitation in dry periods is 100-200mm, in wet periods - 300-400 mm; the proportion between dry and wet years is 7:3 (Mamatov and Kurnanbaev 2006).
  

These assumptions are valid and justified by the analysis of the Aydar-Arnasay lakes system carried out by the national experts and research results published in scientific papers.
The list of assumptions provided above is not exhaustive. More assumptions used for the development of a particular model block are considered in corresponding sections below.

3.