The water conservation function and appropriate management of agricultural land

摘要

Fostering river flow and ground water by temporarily retention water to lighten the peak discharge of flood flow and slowing the effluent stream detention of water is called the water conservation function. The water conservation function of forestsis fully understood, and it plays a role in efforts to conserve our forests. But awareness of the water conservation function of agricultural land is far lower than that of the same function served by forests. For this reason, it is necessary to preserve agricultural land and irrigation and drainage facilities with the assistance of people who are not farmers by scientifically evaluating the water conservation function of agricultural land and facilities based on data and to achieve a social consensuson the nature of this function. This report is an explanation of the water conservation function of agricultural land and of the irrigation and drainage facilities that help achieve such a consensus. We have introduced the "water buffering capacity" as amacro indicator of a water conservation function, and explaining water conservation functions based on the results of a water balance survey and of run-off analysis. These results reveal that agricultural land and agricultural facilities have substantial functions that play important role in water conservation.