Determining Impact of Irrigation on Ground Water

Agriclture in arid and subarid regions comprising some 22% of the world's arable land, depends on supplemental irrigation. Irrigation eventually may lead to salinity problems and has led to the theory that a civilization cannot long endure when dependent on irrigated agriculture. However, effective planning and management could delay or perhaps avert the ultimate destruction of the irrigated system. It may be too late for an effective action if the symptoms of salinization have already begun. A simple inexpensive modeling procedure is described here which may be used to determine the long term effects of irrigation and agricultural practices on the system. Pauma subbasin in Southern California is used to demonstrate the application of the model.