| Abstract | The Prairie Ronde fan, a discrete glaciofluvial deposit in southwestern Michigan, contains a productive but highly vulnerable unconfined aquifer used for irrigation, municipal, and domestic supply. A comprehensive hydrogeological study of the aquifer delineated shallow, local flow systems that interact with ponds and wetlands on the fan surface, overlying a deeper intermediate/regional flow system extending to the base of the glacial drift. Ground water within the shallow flow systems contains tritium concentrations indicative of a post-bomb age and is heavily impacted by nonpoint source contamination. Nitrate commonly exceeds drinking water standards in the shallow flow system. Although no continuous physical barrier separates the two flow systems, the deeper flow system is generally lacking in tritium as well as nonpoint source contaminants derived from surface land uses. High capacity pumping from the deeper flow system, however, will likely draw contaminants downward from the shallow flow system. Background-water quality in the aquifer is controlled by equilibrium with calcite and slight undersaturation with respect to dolomite. No spatial trends in major ions were observed, suggesting that carbonate mineral equilibrium is achieved rapidly in the vadose zone and further chemical evolution along ground-water flow paths is minimal. Iron concentrations are highly variable in the aquifer and not correlated with depth. Recharge from lakes and wetlands is a significant cause of elevated iron concentrations in the shallow flow systems. |
| Text | 212575 1996 10.1111/j.1745 6584.1996.tb02030.x ISI Web of Science WOS A1996UJ26900014 Scopus 2 s2.0 0030151237 Ground water Quality and Flow in a Shallow Glaciofluvial Aquifer impacted by Agricultural Contamination Kehew A.E., Steinmann W.K., Barrese P.G., Passarella G., Peng W.S. Alan E. Kehew, W. Thomas Straw Department of Geology, Western Michigan University, Kalamazoo, Michigan 49008. William K. Steinmann Envirologic Technologies Inc., 2960 Interstate Parkway, Kalamazoo, Michigan4900 I. Patrick G. Barrese Soil and Materials Engineers, Inc., 43980 Plymouth Oaks Blvd., Plymouth, Michigan48170. Giuseppe Passarella CNR IRSA, V. Ie F. De Basio, 5, Bari, Italy. Wei Shyuan Peng Dell Engineering, Inc., 3352 128th Ave., Holland, Michigan 49424. The Prairie Ronde fan, a discrete glaciofluvial deposit in southwestern Michigan, contains a productive but highly vulnerable unconfined aquifer used for irrigation, municipal, and domestic supply. A comprehensive hydrogeological study of the aquifer delineated shallow, local flow systems that interact with ponds and wetlands on the fan surface, overlying a deeper intermediate/regional flow system extending to the base of the glacial drift. Ground water within the shallow flow systems contains tritium concentrations indicative of a post bomb age and is heavily impacted by nonpoint source contamination. Nitrate commonly exceeds drinking water standards in the shallow flow system. Although no continuous physical barrier separates the two flow systems, the deeper flow system is generally lacking in tritium as well as nonpoint source contaminants derived from surface land uses. High capacity pumping from the deeper flow system, however, will likely draw contaminants downward from the shallow flow system. Background water quality in the aquifer is controlled by equilibrium with calcite and slight undersaturation with respect to dolomite. No spatial trends in major ions were observed, suggesting that carbonate mineral equilibrium is achieved rapidly in the vadose zone and further chemical evolution along ground water flow paths is minimal. Iron concentrations are highly variable in the aquifer and not correlated with depth. Recharge from lakes and wetlands is a significant cause of elevated iron concentrations in the shallow flow systems. 34 http //onlinelibrary.wiley.com/doi/10.1111/j.1745 6584.1996.tb02030.x/abstract Articolo su rivista internazionale con IF Received December 1994, revised June 1995, accepted June 1995. Ground water Quality and Flow in a Shallow Glaciofluvial Aquifer impacted by Agricultural Contamination Articolo su rivista internazionale con IF Received December 1994, revised June 1995, accepted June 1995. INT_Articolo_in_Rivista_J_02.pdf Articolo in rivista Blackwell 0017 467X Ground water Ground water Ground water Ground water. GW giuseppe.passarella PASSARELLA GIUSEPPE TA.P04.005.008 Integrazione di metodologie per il monitoraggio e la modellizzazione per la gestione delle risorse idriche |
