Policy Analysis of Water Management for the Netherlands

This volume describes the District Hydrologic and Agriculture Model (DISTAG). It describes methodology only, and contains no results or conclusions about water management for the Netherlands — such results appear in other volumes. DISTAG simulates the hydrologic cycle. It assumes that the amount of rain and conditions determining evaporation are known, as are hydrologic conditions (e.g., quantity of water stored in the soil) at the beginning of a time interval. It then determines how much water actually evaporates, both directly and in the form of transpiration from plants; how much water and salt remain in the soil; how much water and salt drain out of the soil into the surface water system; and the groundwater level. In addition to these strictly hydrologic quantities, the model also computes quantity of water and operating cost of sprinkling and drought and water damage to crops.