在开发任何半细粒自流含水层作为给水来源时，一个关键的基本假设是，水质将随时间而变化。要解决的问题是如何发展供水，以最大限度地降低变化率。本文讨论了佛罗里达州南部碳酸盐含水层的发育和东部沿海平原硅质碎屑含水层的发育。从本次讨论中可以得出的一个主要结论是，如果对给定场地的地下水系统没有很好的了解，那么井场的设计应该非常保守。 这意味着增加生产井间距和生产井数量，以有效降低单井产量。随着获得更多数据，可以对井场设计进行更改，以降低成本。

A key basic assumption in the development of any semiconfined artesian aquifer as a source of feedwater is that the quality of the water will change with time. The issue to be resolved is how to develop the water supply to minimize the rate of change. This paper discusses the development of carbonate aquifers in South Florida and the development of siliciclastic aquifers of the Eastern Coastal Plain. A major conclusion that can be drawn from this discussion is that if the groundwater system is not well understood at a given site, the design of the wellfield should be very conservative. This means increasing production well spacing and increasing the number of production wells to effectively decrease individual well yields. As additional data are obtained, changes can be made to the wellfield design to reduce costs.