The irrigated area in the Aral Sea basin totals about 7. 5 million hectare. Part of the water supplied to this area is consumed by the irrigated crop; the remainder of the supplied water drains to the groundwater basin, to downstream depressions, or back to the rivers. During its use, however, this drained part of the water accumulates salts and chemicals. The disposal of this polluted water causes a variety of (environmental) problems. If the percentage consumed water of the total water supply to an irrigated area (the so-called overall consumed ratio) can be increased, less water needs to...

In the context of water management, structures that measure the flow rate in open channels are used for a variety of purposes: (i) In hydrology, they measure the discharge from catchments; (ii) In irrigation, they measure and control the distribution of water at canal bifurcations and at off-take structures; (iii) In sanitary engineering, they measure the flow from urban areas and industries into the drainage system; (iv) In both irrigation and drainage, they can control the upstream water at a desired level. This thesis represents an attempt to place such flow measurements on a solid...

Managing land and water is a complex affair. Decisions must be made constantly to allocate and use natural resources. Decision and action in any use of resources often have strong interactions and side-effects on others, therefore it is extremely important to monitor and forecast the impacts of the decisions very carefully. Reliable information and clear data manipulation procedures are compulsory for monitoring and forecasting.
Remote Sensing has considerable potential to provide reliable information. A Geographic Information System is an easy tool for manipulating and analysing the...

The irrigated area in the Aral Sea basin totals about 7. 5 million hectare. Part of the water supplied to this area is consumed by the irrigated crop; the remainder of the supplied water drains to the groundwater basin, to downstream depressions, or back to the rivers. During its use, however, this drained part of the water accumulates salts and chemicals. The disposal of this polluted water causes a variety of (environmental) problems. If the percentage consumed water of the total water supply to an irrigated area (the so-called overall consumed ratio) can be increased, less water needs to...