 |
Thursday, September 02, 2010
|
|
 |
|
|
| | Email this article • Print this article | LS Power water use permit must pass aquifer test with DNR
BY DENISE MARTIN
There were about 50 people attending a program June 2 at Sunrise's Wilcox Community Center, where speakers shared their expertise on local aquifer systems and how a proposed electric generating station's operational needs might affect local hydrological conditions.
LS Power LLC seeks to develop a natural gas/fuel fired peaking electric generating facility, next to the Xcel Substation, in Lent Township.
One issue of great interest is the need for water for cooling generating equipment. There have been no permit applications filed by the developer; but in recent public meetings the potential for the electric plant to consume up to 5 million gallons per day has been put forward.
Legislation adopted in the just-completed Session caps this project at pumping no more than 2 million gallons per day, averaged out over a 30-day period. LS Power is looking for water supplies from wastewater treatment facilities in the nearby region. Citizens have concerns about this cap being enforced, and have questions about negative effects from pumping even 2 million gallons of water.
Sunrise meeting speakers last week presented field research and studies done on groundwater and recharge capacity in the general area of the project. What the experts say is: Chisago County water usage is estimated at 111 gallons, per day, per person. (This is based on the 2000 census.)
This amounts to about 4.5 million gallons per day consumed in Chisago County.
"What I can't tell you is what's available," said Dale Setterholm, MN Geologic Survey Association Director. Setterholm said the research is less clear on what's available.
Data for a "geologic atlas" of Chisago County has been compiled and organized for two years. Setterholm said geologic survey teams ordinarily need three years to complete the work. (A geology atlas has been completed for 25 of 87 counties in Minnesota.)
John Nieber, of Lindstrom, spoke next on "renewable flux." This is what renews our groundwater and surface water stores through rain and snowfall. Minnesota is a headwaters state and doesn't get water flowing into it from large water sources elsewhere.
Regions of Minnesota are defined by their permeable soil types, geological formations, depths of aquifers, etc. Knowing this and knowing the renewable flux contributors, there can be educated estimates on what is sustainable local consumption of ground and surface water.
The county gets an annual average of 30 inches of rainfall. The estimate is that 7.68 inches become run-off or stream flow, this is what's useable in lakes, recharges supplies that we can drink, etc. The rest, or 75 percent of the total, is lost to evapo-transpiration, explained Nieber.
To avoid over-depletion of water resources, Nieber said we must not consume more water than what is replenished. Using up water supplies at a faster rate than renewable flux quantities is dangerous.
Aquifers, where quantities of water move slowly beneath the earth's surface and can be stored, have been plotted out in Chisago County based on years of well drilling reports, required to be submitted when any well is punched.
Jerry Spetzman, County Water Plan Coordinator, shared data on 8,000 wells verified in Chisago County. Well drillers tell authorities where the wells are, at what depth water was located and which soils were encountered along the way. (Permits are held by special farming operations but also by municipalities so consumption through these permits is included within the Geologic Survey estimates on per capita consumption.)
Spetzman said based on reports by permitted water-users (10,000 gallons per day and more) there's 4.4 million gallons pumped every day, in Chisago County, by these permit-holders alone.
A report released in 2008 from the MN Environmental Quality Board also calculates net water use as a percentage of renewable resource, and the bottom line is in this county 5 percent of the renewable flux is used by humans.
Nieber reminded those at this meeting that research is based on averages and there's always droughts or wet years that can skew any calculations. Plus, he added, "All we've talked about is quantity of water, not quality."
Mike Mueller, Regional Hydrologist for the Dept. of Natural Resources, told the audience there have been two meetings with LS Power and its local consultants Barr Engineering. The DNR is prepared to move forward on monitoring an aquifer test, but first, Barr has been asked to supply information on private wells in the vicinity of the electric plant site. Mueller said about 100 wells exist within a mile and a half radius of the LS plant site.
Even though there's quite extensive research already done on Chisago County groundwater, its aquifers and soils, Mueller said, "The ultimate science is to do an actual aquifer test."
LS Power will drill test wells at the site and for 30 days the state will work closely with LS Power engineers performing a maximum pumping test, drawing 2 million gallons per day. Mueller said local wells within an "area of influence" will be watched for "drawdown." Local wetlands and other natural water storage areas will also be monitored during this test.
In applying for a permit to use the maximum 2 million gallons daily, Mueller said criteria in state law tell the DNR Commissioner what he can consider. The "103G" rules require a determination that water supply remains adequate for higher priority residential and public use. The commissioner may also weigh the economic benefits of a permit project. The commissioner gets public input at various stages of the permit review.
Mueller explained that the Mt. Simon-Hinckley aquifer, in the area of the power plant, is protected by state law within the seven county metro area but not in Chisago County. In 1992 the legislature restricted access to this aquifer in the Twin Cities to only potable water uses, due to concerns about industrial consumption out of this aquifer and possible contamination.
A Q and A session wrapped up the meeting, and State Senator Rick Olseen and Rep. Jeremy Kalin spoke briefly with the audience. The program was sponsored by the Friends of the Sunrise River.
|
|
|
|
|