EDUCATING CITIZENS ABOUT THE LIMITS OF WATER SUPPLY: HYDROGEOLOGY FOR THE PUBLIC GOOD IN AMES, IOWA

The limits of water supply – particularly groundwater – are not well understood by citizens in humid areas. Water scientists, including hydrogeologists, generally avoid presentations to the public on the subject. Science (in general) and hydrogeology (in particular) could be helped greatly by individuals studying local water supply problems and reporting back to the local community. The “nerdy” scientist is then your neighbor, has instant credibility, and can be trusted to do what is best for public good. Drawing inspiration from the watershed restoration efforts of Mary Stoertz in Ohio, the lead author answered the call in 2005 when dropping water levels and a 50 Mgal/yr ethanol plant – drawing 200 Mgal/yr from the Ames aquifer – sparked concern about the sustainability of aquifer. The City of Ames, Iowa (population~50,000) relies on the alluvial/buried valley aquifer for drinking water. The 3-year project has been very different and required appearances in public/church forums, writing news releases, doing radio interviews, starring in a cable-TV video, and prompted conversations in department stores, supermarkets, school concerts, and in the kitchens of in-laws – all providing opportunities to educate the public. We cite three educational highlights. First, a 2-D, analytic element, groundwater flow model (GFLOW) has shown that the emergency water supply, Ada Hayden Lake, is not an inert “bathtub” but instead a source of recharge to the Ames aquifer. Second, the redox geochemical/microbiological environment of the aquifer has reduced specific capacity; hence, old wells might have been rehabilitated prior to constructing new ones. Third, a larger GFLOW model was constructed for 2,112 sq. km region of central Iowa. With the aid of PEST, calibration of 134 hydraulic head and 3 baseflow targets produced a MAD of 1.1 m and 0.01 cms for hydraulic head and baseflow, respectively. Despite previous ideas that South Skunk River and Squaw Creek recharge the aquifer, the model clearly shows that both are gaining streams and that a substantial underflow component occurs in the unconfined aquifer south of Ames. This "discovery" will help site a new well field free from induced infiltration from the river. In summary, we believe this project brings science and hydrogeology into the public forum, educates citizens about the limits of water supply, and benefits the public good in Ames, Iowa.