Computerized Procedure for Estimating Costs of Desalting Systems

The need for an economical method of providing good-quality water to customers has always been a problem for many communities in South Dakota. The state lies entirely in the Great Plains region, where there is a lack of natural surface water supplies, and where rainfall averages from less than 16 in./yr in the western part of the state to about 27 in./yr in the east. Presently, the only surface water that can provide an adequate full-time supply is the Missouri River, which crosses near the middle of the state and flows in a southeasterly direction. There are four major impoundments of this river in South Dakota from which a municipal water supply can be procured. However, a problem still exists in that the majority of the cities in the state are a considerable distance from the river, and water transmission costs are beyond the financial capabilities of most communities. As a result, nearly all municipalities in the state receive their water from underground sources. Wells in the state range from depths of 20-30 ft, which tap shallow aquifers in glacial deposits to depths in excess of 4,000 ft, which penetrate artesian aquifers in various bedrock formations.