Module 9 - China: Consumptive Use in Water Resource Management for Productivity, Equity, and the Ecology

Historical irrigation development in the southern part of the Xinjiang Uygur Autonomous Region in northwestern China has resulted in a severe reduction in downstream flows and in negative environmental impacts. The Tarim Basin is a desert climate (50 millimeters annual rainfall), and the water source is principally high mountain snow and glacier melt into tributaries of the Tarim River, as well as some groundwater that is recharged, mainly from irrigation.

In the past, irrigation development in the Tarim Basin involved continual expansion of irrigated area without consideration of the ecological balance or of other users (including downstream users) affected by reduced water supply. Attempts to restrict water usage were perceived by farmers and irrigation technicians as a regulatory measure that would result in decreased productivity and production potential.

Project Objectives and Description

The Tarim Basin II Project was designed to implement a system of sustainable water resources development and management. The project has the potentially conflicting objectives of increasing downstream flows to preserve the environment of the lower reaches of the Tarim River, while increasing the incomes of upstream farmers who depend on irrigated agriculture. The project has supported the establishment and strengthening of the Tarim Basin Water Resources Commission (TBWRC), with overall responsibility for water resources management in the basin. TBWRC has set quotas for water use in the tributary sub-basins and has implemented a system to monitor and enforce the quotas. In addition, physical and management measures on the main Tarim River will deliver more water downstream.

The project is based on the concept of “beneficial consumptive use,” in which knowledge of the hydrological process and a basin-wide approach are used to optimize the availability and use of water to meet the objectives of increased production and productivity, equitable access across the basin, and long-term preservation of the hydrological and ecological balance.

Water consumption in the upstream sub-basins is presently at the limit allowed by the quotas established and enforced by TBWRC, so no additional water is available; in other words, total ET in the sub-basins is fixed at present levels. ET was divided into three components for project planning and management purposes: (1) consumptive use (CU) related to human activity (mostly in irrigated agriculture); (2) beneficial ET (BET) from trees and green areas along rivers and in and around oases; and (3) nonbeneficial ET (NBET), mostly in low-lying areas with high water tables (including areas of salinization) and evaporation from nonecologically beneficial water surfaces.