A Conceptual Planning Process for Management of Subsurface Drainage

Abstract

Management of subsurface agricultural drainage is a complex resources management issue. In California, for example, over one-half of the San Joaquin Valley (Valley) has no natural outlet for surface or subsurface drainage. As of 1987, an area of approximately 750,000 acres had ground-water levels within 5 feet of the surface and this shallow water area is continuing to expand. This affects agricultural production and introduces obstacles to conventional irrigated farming. In addition, most of the drainage contains relatively high levels of contaminants such as selenium which greatly complicate the drainage disposal effort. The variability and interrelationships among hydrology, soil characteristics, land use, institutions, and opportunities for drainage disposal within the drainage problem area required the San Joaquin Valley Drainage Program (SJVDP) to consider a systems approach to evaluate alternative solutions and select a recommended plan. This approach includes identification, quantification, and awareness of the interdependency of major variables.