TY - JOUR AU - Grismer, Mark E. AU - Tod, Ian C. AU - Robinson, Frank E. TI - Drainage system performance after 20 years JF - California Agriculture JO - Calif Agr Y1 - 1988/05/01 VL - 42 IS - 3 SP - 24 EP - 25 PB - University of California Agriculture and Nature Resources SN - 0008-0845 UR - http://www.ucanr.edu/sites/calagjournal/archive/?article=ca.v042n03p24 AB - As part of a study of the longevity and effectiveness of clay, bituminous fiber, and concrete drainage pipes, several pairs of these pipes were installed in a heavy clay soil at the Imperial Valley Agricultural Center at El Centro, California in January 1964. Drain lines were laid at a depth of 7 feet and a spacing of 120 feet. Bituminous-fiber drains were installed in a fiberglass envelope; washed gravel was used to enclose the clay and concrete pipes.