News Release, Kansas Geological Survey, Sept. 4, 1998
Survey water specialist Marios Sophocleous edited the book, Perspectives on Sustainable Development of Water Resources in Kansas, which points out flaws in a traditional management concept known as safe yield.
Under a "safe yield" approach to water management, says Sophocleous, water use is limited to the amount of annual recharge--that is, the amount replenished naturally through precipitation and water seepage from the surface.
Sensible as this simple formula seems, Sophocleous says, "if you use safe yield as a definite recipe, you end up depleting other water supplies." Like many simple concepts, safe yield doesn't tell the whole story.
The problem is that safe yield ignores the complex relationships between surface water (lakes, streams, springs, and marshes) and groundwater (water found in underground rock formations called aquifers).
For example, under natural conditions, before wells start pumping, aquifers discharge water to streams, marshes, and springs. The amount discharged equals the amount of recharge. This means that under a traditional safe yield approach, pumping removes groundwater that would otherwise be discharged at the surface. The streams, marshes, and springs eventually dry up.
"This is what has happened to some perennial streams in western Kansas," Sophocleous says.
Sophocleous says that a recognition of the connection between surface water and groundwater is already shaping the way water resources are managed in Kansas. Two of the state's five groundwater management districts now factor in natural ground-water discharge when evaluating new applications to use groundwater.
Promoting a better understanding of the complexities of the water system was one of the goals with this new book. Towards that end, Sophocleous asked nine other water scientists to write chapters discussing issues of safe yield and sustainability from a variety of perspectives. In addition to Sophocleous's chapters on Kansas water resources and sustainability issues, the book includes chapters on water chemistry, agriculture, and climate change. "The book presents the most up to date views on the subject and places the discussion on a sound scientific footing," says Sophocleous.
Sophocleous admits that understanding the complex relationships between ground and surface water is just a first step down the path towards sustainable development, managing the state's water so that both current and future needs are met. "As a concept," Sophocleous says, "sustainable development is still pretty vague. No one knows for sure exactly what it means or how it can be attained."
How the concept will be applied in Kansas remains to be worked out, but it will be different in different parts of the state. In western Kansas, where irrigation sucks up 90% of the ground water, sustainability will be difficult to achieve. In central and eastern Kansas, where there's less irrigation and more precipitation, "sustainability is a possibility," says Sophocleous. But, he adds, "education is vital if consensus on these issues is to be achieved."
Written in semi-technical language, the book contains numerous illustrations and a lengthy glossary.
Copies of the book are available from the Kansas Geological Survey at 1930 Constant Avenue in Lawrence (785-864-3965). The cost is $25.00, which includes sales tax, shipping, and handling. Copies are also available from the Survey's Wichita office (316-943-2343).