Agricultural production has been directly related to groundwater levels. Seasonal variations and irrigated volumes make it difficult to determine the time relation between a given water table and production. There is sufficient field data to establish empirical relationships between groundwater and crop yield. Criteria were proposed to calculate optimum drain spacing as a function of average groundwater depth and of system installation costs. Spacing was found to optimize the relationship between percent production per unit space between drains and the percent cost for piping and installation. The resulting model considers the main physical parameters including hydraulic recharge and conductivity, drain radius and depth, and spacing. Software was developed to create on-screen graphs of the results. The method is illustrated using field data taken from Irrigation District 076, Mexico. The results showed that a relative decrease in yield is accompanied by a large decrease in investment.
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