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Ic ~~~° rye. a Contilllted from gage 9
<br />water levels, development of
<br />conservation plans and inves-
<br />tigation of alternate sources of
<br />water.
<br />"In no case, does the plan
<br />say that, based solely on the
<br />modeling, you can't use this
<br />source," Elvrum said.
<br />Predictions resulting from
<br />the modeling include:
<br />Water levels in the Prairie
<br />du Chien-Jordan aquifer; the
<br />major source of ground water
<br />for most of the metropolitan
<br />area, will decline 5 feet or less
<br />by 2030. But levels will drop up
<br />to 20 feet in Woodbury, Cottage
<br />Grove, Apple Valley and parts of
<br />Afton, Rosemount and Lakeville.
<br />By 2050, some of those
<br />communities will see declines of
<br />30 to 40 feet, and a belt of sub-
<br />urbs rumling from Chanhassen
<br />2050 Model-projected Drawdown in the Prairie du Chien-
<br />Jordan Aquiter Under Long-term Average Conditions, Assuming
<br />Continued Development of Traditional Water Supplies during
<br />SummerConditions
<br />Master water Supply plan -appendix 1
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<br />Created 6y the Me[ropolitan Council on 9/8/2008
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<br />http://gis. mete. state. mn. us/makeamap/
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<br />20 Miles I I
<br />through Medina and into Maple
<br />Grove will experience declines
<br />of 5 to 20 feet in the Prairie du
<br />Chien-Jordan.
<br />In Woodbury and Cottage Grove,
<br />pumps, which now are fed by pressur-
<br />ized water driven up through a rock
<br />layer that confines the Prairie du Chien-
<br />Jordan aquifer, would be drawing water
<br />from beneath the rock layer by 2030 if
<br />pumping continued and was expanded
<br />as it would have to be to meet the two
<br />cities' expected grov,~th. State law that
<br />defines permissible "safe yield" prohibits
<br />such pumping, Elvrum said.
<br />High-capacity municipal pumps
<br />in Woodbury, Cottage Grove, Apple
<br />Valley, Lakeville and parts of Rosemount
<br />and Farmington could interfere with
<br />private wells in those communities as
<br />water levels decline.
<br />l By 2030, water levels-measured
<br />by the height to which water rises in a
<br />well casing-would drop by 50 percent
<br />in a number of communities, including:
<br />Hastings, Inver Grove Heights, Maple-
<br />wood, Newport; Prior Lake, Rosemount,
<br />Savage, Shakopee, South St. Paul, St. Paul
<br />Park and Stillwater. Parts of St. Paul,
<br />Metropolitan Council map showing areas where water levels in the Prairie duChien-Jordan aquifer are projected to decline by 2050.
<br />Areas of biggest decline are: Woodbury, Cottage Grove, Apple Valley, Burnsville, Lakeville, Rosemount and Prior Lake.
<br />but not the area where municipal wells
<br />are located, also would face that kind of
<br />draw-down.. The Department of Natural
<br />Resources considers such a drop to be an
<br />indicator of possible over-use.
<br />Another aquifer, the Franconia-
<br />Ironton-Galesville, will experience water
<br />-level declines in Woodbury, Cottage
<br />Grove, Corcoran, Maple Grove, Prior
<br />Lake and a few other areas.
<br />Many large and small communities
<br />across the metro area will face declines
<br />in their water tables-the saturated soil
<br />and gravel just below the surface of
<br />the land-of 1 meter or more by 2030.
<br />In some cases, water table declines
<br />would dry up wetlands and streams.
<br />Communities predicted to experience
<br />these declines include: Andover, Blaine,
<br />Bloomington, Brooklyn Center, Brook-
<br />lyn Park, Champlin, Corcoran, Dayton,
<br />Eagan, Farmington, Forest Lake, Hugo,
<br />Lake Elmo, Lakeville, Maple Grove,
<br />Osseo, Ramsey, Richfield and Savage.
<br />Elvrum said planners and water utility
<br />managers in many of the affected commu-
<br />nities would not be surprised by the mod-
<br />eling predictions. "We have guessed that
<br />there were going to be problems in these
<br />areas," he said. "Now we have something
<br />to verify that."
<br />Klayton Eckles, Woodbury's city engi-
<br />neer and deputy director of public works,
<br />said he welcomed the Metropolitan Coun-
<br />cil's water plan, and he said it presented
<br />no surprises. Eckles said the particular
<br />problem the modeling projects for Wood-
<br />bury and Cottage Grove by 2030-pump-
<br />ing that would cause a confined aquifer to
<br />become unconfined-would result more
<br />from the peculiar geology of the area than
<br />from unrestrained pumping. "Factures
<br />and Karst mean it's essentially already
<br />unconfined in some areas," he said.
<br />Eckles said Woodbury officials expect
<br />the community will be able to rely on
<br />ground water for the foreseeable future.
<br />But he said officials of the St. Paul water
<br />system have offered to sell water to
<br />Woodbury and other suburbs.
<br />FACETS December 2008
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