the status of minnesota’s groundwater
Post on 24-Feb-2016
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DESCRIPTIONThe Status of Minnesota’s Groundwater. Jason Moeckel, DNR Dale Setterholm , MGS Glenn Skuta, MPCA Bruce Montgomery, MDA Joe Zachmann , MDA Chris Elvrum, MDH Keith Buttleman , Metropolitan Council Jim Sehl, DNR James Stark, USGS. The Problem…. - PowerPoint PPT Presentation
Clean Water Fund
The Status of Minnesotas Groundwater
Jason Moeckel, DNRDale Setterholm, MGSGlenn Skuta, MPCABruce Montgomery, MDAJoe Zachmann, MDAChris Elvrum, MDHKeith Buttleman, Metropolitan CouncilJim Sehl, DNR James Stark, USGS
Mr. Chair, and members, thank you for the opportunity to testify here this morning. My name is Jason Moeckel, I work for the Dept. of Natural Resources, Division of Ecological and Water Resources.
The importance of groundwater and managing it sustainable can not be overstated. Representatives Wagenius and Hansen have asked us to provide you with a status report of Minnesotas groundwater resources. And specifically they have asked us to provide very technical information and use case studies to illustrate our understanding of the challenges we face.
We have organized a series of speakers this morning and carrying into next Tuesday. Each of the speakers will be building on what previous speakers have addressed. The visuals of this room make it particularly challenging to illustrate some of the information we have to share, but well do our best to explain the graphics as we go.
This will be fast and perhaps frustrating for some of you. We have packed a lot of information into a short time, and our intent is to leave some time for questions and discussion at the end.
In the materials provided we have a few summary sheets with key ideas that may serve as valuable reminders for you and perhaps a place to note your questions. 1The ProblemThere are places in Minnesota where we are not achieving sustainability of our groundwater resources and we are currently making decisions with a lack of informationKey RisksOver useContamination
What we hope to leave you with is a much better understanding of our states groundwater resources and appreciation for the challenges we face.
Simply stated the problem we are increasingly recognizing is that there are .2Minnesotas Drinking Water Sources
Municipal Groundwater2.7 million people
75 % from groundwater; drought plan for surface water = groundwaterIn aggregate, about 75% of drinking water comes from groundwater and groundwater is the backup for surface water in the case of drought.3
This map depicts the current status of drought in Minnesota. This is not expected to change very much between now and the end of March. The amount of moisture we get in April and May will play a major role in determining whether conditions get worse or better. This is a significant consequence to small businesses and municipal water suppliers. The City of Fairmont in southern Minnesota is facing a tough situation because they are dependent on a lake to meet their supply needs.
On Tuesday, many of you heard about the challenges that a changing climate brings. Many of the questions you asked had to do with groundwater and drinking water supplies.
As mentioned Tuesday by Dr. Seeley, we are now experiencing floods and droughts in the same year and even in the same location. Duluth Minnesota is an unfortunate example.4
I didnt think it was possible to run out of water in the land of 10,000 lakes. Weve never had any problem before in the 14 years Ive lived here," Mackay said, adding that at least four of her neighbors have had wells run dry in recent weeks.Here is the headline for an article in the Duluth News Tribune from December 31. This area received nearly 10 inches of rain and experienced devastating floods. Who would have thought that by October homeowners would be experiencing wells that do not produce water.
The center of the red circle is the home in question. The dark and light blue dots represent nearby wells, all of which are for domestic supply. This is just one recent example, which illustrates that there are places in Minnesota where we are not achieving sustainability.
The quote also reflects what many Minnesotans believewe are a land of plenty when it comes to water.
Perhaps not so much
This graph represents the cumulative number of wells within the 1.5 mile radius, the red circle on the previous slide. This shows the increase in number of wells over time. If you look at the arrow, which points to 1988, there were just over 30 private wells in the area. Now there are 161. That amounts to more than 5 times the number of wells and use of a limited supply.
When we heard about this developing situation we immediately looked for any information we may have to help understand what may be going on. Unfortunately, the nearest monitoring well is 25 miles away. Basically, of no value.
This community is growing in an area underlain by bedrock that does not yield very much water.
Sustainable do we have sufficient water even in periods of draught6
This recent headline from the Star Tribune on Dec. 23 speaks to the other major risk to our groundwater and that is contamination.
Next Tuesday our colleagues from Departments of Health, Agriculture and Pollution Control Agency will provide you all with the most up to date information about groundwater contamination. What we know and dont know, and the some of the risks. 7Minnesotas Drinking Water
Community Surface Water Supplies
Surface water is used by several large communities, typically where perennial rivers or large lakes and mine pits supply it.In the Arrowhead, geology sometimes rules out drilling a high capacity well so surface water is a great option to have.8Community Ground Water Supplies
Minnesotas Drinking WaterGroundwater is used everywhere else for drinking water. It rarely needs expensive treatment and can usually be used just as it comes out of the ground. 9Private Wells
Minnesotas Drinking WaterDNR does not track the water used from these private wells because they are not required to have permits. When we add up groundwater use from permitted users, we can see this trend:10Groundwater Provinces:
A complex resource!
Recall this image from our last presentation. Each of these have different characteristics and variability that must be considered when determining how many wells and where to locate them.
The availability and sources of potable groundwater vary significantly across Minnesota. In some parts of the state groundwater resources are limited and local aquifers of limited extent may be extremely important as a primary potable water supply. These aquifers may be overlain by relatively impermeable layers of glacial till and therefore be more protected from surface sources of contamination, or they may be at the ground surface and highly vulnerable to contamination.
In the Twin Cities area and extending to the southeast most potable groundwater comes from large regional aquifers that extend over significant distances.
When an aquifer is composed of limestone or dolomite, groundwater may flow rapidly through large fractures and be extremely vulnerable to contamination. This is referred to as a karst aquifer and is common in southeast Minnesota.
In central Minnesota, extensive shallow sand deposits from glacial outwash are the primary source of groundwater and may also be highly vulnerable to contamination.
In much of Minnesota, the characteristics and conditions of an aquifer may vary significantly over very short distances. Because of this variability in the characteristics of aquifers, information is generally needed on a local scale to properly manage groundwater resources. 11Private Wells
Twin Cities Drinking Water
Surface Water Supplies
Ground Water Supplies
Some of you may live in the Metropolitan Area. If you have your own well its probably one of these little pink dots along with all of the other wells that dont use enough water to require a permit. The green and red dots show ground and surface water permits the bigger the dot, the more water is being used. The Twin Cities is at the confluence of two major rivers - ideally located to use surface water when it is abundant and groundwater when it is not. This concept is called conjunctive use. Investment in planning for conjunctive use is something I hope to hear more about as we work with the Metropolitan Council and others on Metro water supply issues. 12West Metro (45 12)
Here is what the water level in the PdC-J is doing out by Lake Minnetonka. It is very good to have a long period of record, though not so good to see what it reveals. The greatest drawdown ever measured in this well occurred this past September (-50.002 9-6-2012).13
water supply interferenceGround water withdrawal affects surface water and ground water users
14How do conflicts occur? Here is an example of what can happen in a conflict. The top dashed line shows the water level before high volume pumping. Water is obtained by the domestic well and the nearby surface water body; in this case, a wetland (plants) also has access to the groundwater.
Once the high volume pumping well starts to pump, the drawdown of the aquifer (cone of depression) brings the water levels down to what you see here in blue. Now the intake of the well is above the water level in the aquifer and the wetlands access to the groundwater is cut off.