The Lake Aidar (Aidar-Kul) belongs to the man-caused Aidar-Arnasai system of lakes, which covers an area of 400 000 hectares (approx. 988,422 acres). This system includes 3 brackish water lakes (Aidar-Kul, Arnasay and Tuzkan) located in the salines of south-eastern Kyzyl Kum (now in Uzbekistan and Kazakhstan). Up to middle of the last century Arnasai lowland most of time during a year remained a dry saline. Only in spring at the lowland glistened small ephemeral Lake Tuzkan disappearing in hot time. In the early sixties Syr Darya was dammed up. Simultaneously Chardarya irrigation dam was constructed. There were provided the floodgates in the dam for the flood control. Soon in 1969 an extremely raging flood happened. Since February 1969 till February 1970 almost 60 percents of average annual Syr Darya's water yield (21 cubic kilometers) were drained from Chardarya Reservoir into Arnasay lowland. In such a way new lakes was unintentionally created. Since 1969 Lake Aidar constantly receives the waters of Syr Darya River when they overflow capacity of Chardarya Reservoir. This gradually filled up the natural cavity of Arnasai lowland to create the second largest (after Aral Sea) lake at the region. In 2005 Lake Aidar has contained 44.3 cubic kilometers of water. Today the area of Lake Aidar amounts 3,000 sq km (approx. 1170 sq mi). It is nearly 250 km (approx. 155 miles) long and up to 15 km (approx. 9 miles) wide.

Mineralization of the water in Lake Aidar averages only 2 gram (0,07 ounces) per one 1 liter.

Many sorts of fish including (Sazan) (Cyprinus caprio), Pike perch (Stizostedion lucioperca), Bream (Abramis brama), Cat-fish (Silurus glanis), Hzereh (Aspius aspius), Chehon (Pelecus cultratus) Ophidian fish (Channa argus) were introduced to the Lake, which nowadays works as a source of industrial fishing. The lake system provides between 760 and 2,000 tones of fish annually (according to statistic data between 1994 and 2001).

In addition to animality common for Kyzil Kum, there are many kinds of water birds migrating from Aral Sea that make their homes around the lake.

The Lake Aidar is located away from inhabited locality, therefore around the lake there is perfect silence. At the present time 345 families (near 1760 people) reside near the lake.

The region of Aidar Lake is an area of great potential for fishing, yurting and camel-back riding tourist activities.