Introduction: Benefits of Flexible Water Delivery

This issue contains two papers by Merriam et al. that describe the concept and application of flexible irrigation water supplies. The papers are the final submittals of a task committee on the Benefits of Providing Flexible Water Delivery formed in 1995. The task committee presented a series of nine papers at the 27th IAHR Congress in August 1997. The purpose of the task committee was to demonstrate through case studies the economic benefits of providing flexible water availability at the farm level and the residual benefits of water conservation, reduced drainage, improved return water quality and reduced operational costs to the purveyor. A flexible water supply allows the farmer the opportunity to choose an on-farm system that best meets the needs of the desired crop, the cost and availability of labor, and other economic or social situations. This flexibility needs to be in terms of rate, frequency, and duration of supply. A rigidly controlled rotational system can reduce the efficiency of even the most sophisticated, well-designed on-farm system. Flexible supplies can allow furrow and border strip systems to select and adjust optimum instanta-