In the Soviet Union, water and energy resources were managed in an integrated and top-down approach. Water resources were used for the best Union-wide benefit, to which each republic contributed. For Central Asia, the priority was cotton production, and therefore the whole Central Asian water management system was oriented toward this goal. In this respect, two important inter-republican governance mechanisms were established. One is the water-energy exchange system among the republics and the other are the water withdrawal quotas for each republic. Both have had a tremendous impact on today's water usage patterns and policy strategies.
The quota system (see table on page 23) favours the irrigation needs of downstream countries. Compared to the data on water formation, the quotas show that those republics where most water resources originate-the Kyrgyz and Tajik SSRs-have the right to use only a small amount. The downstream SSRs of Kazakhstan, Uzbekistan and Turkmenistan were entitled to use most of the water resources as most of the population of central Asia lived here and most of the cotton production of the Soviet Union took place in those republics. These quotas reflected historical and geographical conditions and actual needs. However, after independence, this arrangement did not reflect the needs and interests of the upstream countries, which now had to make best use of their resources to achieve national development. Nevertheless, the water quotas established even regarding smaller rivers are still in place. It is a highly political issue to assess and potentially re-negotiate them, as this exercise may ultimately affect the end the socioeconomic stability of each state.
The second important inter-republican governance mechanism was the establishment of the water-energy exchange system among the republics. As explained above, in the two upstream Kyrgyz and Tajik SSRs, huge reservoirs were constructed in order to store the water until it was needed in the downstream countries for irrigation. The original aim of the attached hydropower plants was only to provide energy in peak times, while the regular needs were covered by the unified energy system. Since independence, this has changed. The unified energy system broke down, and downstream states demanded market prices for their energy fossils. As a consequence, the upstream states have increasingly been using the dams for hydropower generation in order to cover their domestic energy needs.
Hydropower production is a non-consumptive water usage; the regulation in this case does not have to address the general amount of water withdrawal (like the quota system), but instead has to determine the time and seasonal amount of water release from the dams. This is a contested task, as there is a trade-off between water needs for irrigation and for hydropower production. Water is needed for irrigation purposes during the growing period in spring and summer, while energy needs are highest in winter. Thus, while the downstream states of Kazakhstan, Turkmenistan, and Uzbekistan especially need water for irrigated agriculture, the upstream states of Kyrgyzstan and Tajikistan need the energy produced by water discharge in winter. Due to a lack of working management mechanisms, these rival usage interests have caused irrigation water shortages downstream as well as energy shortages upstream in recent years.
The Soviet legacy thus brought up two questions that had to be addressed by the new states: How to share water concerning the quantity of water withdrawals, and how to share water concerning the timing of water releases.