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, "'3. ,-,'., . ~ ",", .; _._-'"~~,",-~. ~ I ~ ~ I ~ waterlogging in areas downgradient. Waterlogging in other areas is caused by subirrigation because the water table is intentionally raised to the plant root zone, The average annual delivery of irrigation water in the San Luis valley is about one million acre-feet to about 600,000 acres of land. Development since 1900 has been confined to improvements in existing systems and installation of many irrigation wells, both artesian and pumped. Severe wa ter shortages occur, particularly during the latter part of July and during August and September or after the snow melt season, Fot. many years water users have attempted to solve this problem by storing water in the subsoil for use later. This process is becoming increasingly difficult due to installation of numerous pumps. The area north of the Rio Grande is a closed basin with no return of surface flow to the Rio Grande. The Bureau of Reclamation's Closed Basin Project will alleviate this condition when completed, 2,2 BACKGROUND , II In past years the Valley irrigation ditches diverted as much as 3,500 cfs from the river's peak flows for the use of valley irrigators, which in turn resulted in a substantial flood control benefit to the Valley communities. -. A However, sOUrces in the Valley determined that agricultural areas in the Valley were already fully saturated and consequently there was little or no demand for water to be diverted from the Rio Grande to, the farmers' fields, The unprecedented series of high water years in the Rio Grande drainage had filled the reservoirs and restored ground water conditions to the highest levels in recent history. In fact, the farmers' fields had become so saturated that tractors frequently became mired, ~ ~ ... ~ A solution to the problem, favored by many of the interests in the Valley, was to embark upon an immediate program of repair and rehabilitation of the drainage systems leading east from the irrigated area into the Closed Basin Project sump. The required repairs to these drains was due to a history of dry years where irrigators were able to use all the water rights authorized to them, The original drains that emptied into San Luis Lake were not maintained, and in some cases were covered over. Before the beginning of the wet cycle San Luis Lake was dry, ~ ~m The reconstruction of the drains would permit water currently saturating the fields to be drained into the sump land to the east which. in turn, would permit diversion of additional flows from the river. In addition, there would be an opportunity for flows diverted from the river to be delivered to the Closed Basin sump. A A