The Shrinking White Bear Lake EarthCache

This cache has been archived.

Grey Wolf and Wild Rice: After a lot of thought , I have decided to archive this Earthcache. While the lesson was powerful in the past, it has diminished since the lake has pretty much returned to it's normal level.

Just to note:
When published, the waterline was about 400 feet out.
Water levels continued to recede until the water was about 750 feet out.
Today, the waterline is within 75 feet of the coordinates.

A lot of change has occurred over the past 7 years.

Thanks to all who visited. Sorry, but any new found logs will be deleted.

It has been great to bring this lesson of lake level fluctuation to the geocaching community.

Grey Wolf

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Hidden : 7/6/2011
Difficulty:
1.5 out of 5
Terrain:
1.5 out of 5

Size: Size: other (other)

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Geocache Description:

As legend has it, the 10,000 Lakes of Minnesota were formed from the footprints of Paul Bunyan and Babe the Blue Ox while they wandered blindly in a deep blizzard. But that's just legend, so read below----

At 2,417 acres of water surface, White Bear Lake is the largest lake in Ramsey County. Even with the shrinking water level of recent years, Bald Eagle's area of 1,269 acres is still a distant second. In recent years, White Bear Lake has been suffering from a major drop in water levels. Below is a chart of lake levels recorded from 1924 to 2006:
Since 2006, more precise measurements have been made and on 10/19/2010, the lowest water lever ever recorded in modern history was 919.43 feet above sea level. While 4 feet below the average does not seem like a lot, the amount of lakebed that has become exposed is massive.

GEOLOGY/HYDROGEOLOGY

Bedrock Geology
White Bear Lake is underlain by St. Peter Sandstone and Prairie du Chien group bedrock units. The greatest part of the lake has St. Peter underneath it. The St. Peter Sandstone is a fine to medium grained quartz sandstone. In its lower zone, it is composed of mudstone, siltstone, and shale with interbedded coarse sandstone, which acts as a confining unit. The upper part of the Prairie du Chien Group is composed of thin-bedded dolostone with sandstone and chert. The Lower part is composed of thick-bedded dolostone. The St. Peter rests uncomfortably on the Prairie du Chien. Note: the Jordan Sandstone lies beneath the Prairie du Chien Group. It is a medium-grained friable quartz sandstone. It is in direct hydrologic contact with the basal Prairie du Chien. In effect, the two units act as a single aquifer.

Depth to bedrock varies from less than 30 feet on the southwest shore to greater than 200 ft on the northeast shore. The majority of the lake area appears to have a thickness of surficial deposits between 50 and 150 feet thick.

Surficial Geology
White Bear Lake is part of a chain of lakes that formed from blocks of ice lodging in bedrock valleys and the subsequent melting of the ice creating depressions in the landscape. On top of the bedrock units are several units of glacial origin covering the majority of the lake area. A deeply incised bedrock valley is found on the northeast end of the lake.

The sequence of glacial deposits in the eastern portion of the lake from bottom to top are: olive brown glacial till deposits of pre-Wisconsin age; reddish-brown, sandy to loamy unsorted glacial till associated with the Superior Lobe; and, directly beneath the lake, sandy to gravely outwash associated with the Superior Lobe.

The western portion of White Bear Lake is underlain, from bottom to top, by: meltwater stream deposits of medium to coarse grained sand associated with the Superior Lobe; loam textured till associated with the Grantsburg Sublobe with bands of Superior Lobe till; and, directly beneath the lake, sandy lake sediment consisting of fine to medium grained sand with silt and clay associated with the Grantsburg Sublobe. The western portion of White Bear Lake is on the edge of the southern extent of the Anoka Sand Plain that was created by outwash from the melting of the Grantsburg Sublobe of the Des Moines Lobe.

Hydrogeology
The Prairie du Chien/Jordan formation are one of the two major aquifers in the Twin City area (the other is the Mount Simon). The St. Peter Sandstone also supplies water locally. Some units of the glacial material act as water table aquifers that interact with White Bear Lake. Potential yield from the St. Peter Sandstone is less than 250 gallons per minute (g.p.m.) and from the Prairie du Chien/Jordan is less than 1000 g.p.m. (1000-2000 g.p.m. at SE 1/4 of White Bear Lake)
The ground water flow direction in the water table aquifer is generally toward the west/northwest. The bedrock aquifers have higher heads at White Bear Lake than at the Mississippi River near St. Paul and their ground water flow direction is generally toward the southwest.
(source:Report to the Legislative Committee on Minnesota Resources June 1998 Minnesota Department of Natural Resources Waters)


Where is the water going?


When the lake fell to similar levels in 1998 and 1989, there was a lot of concern, but old time residents reminded everyone that fluctuation in lake levels was a common occurrence and nothing to be concerned about. It happened before and the lake always returned to normal. In May of 2007, the water level was at 922.69 feet, just short of the average of 923.42.

The loss of water in recent years has been a cause of concern for many local groups. The City of White Bear Lake, White Bear Township, the White Bear Conservation District, the USGS, and local homeowner's groups have all attempted to find answers to the issue. Numerous studies have been conducted to see why the lake is losing water. One early thought was that it was solely due to the fact that White Bear Lake was an ice-contact lake formed with a very small watershed and nearby Bald Eagle Lake was maintaining its water level due to having a number of streams flowing into it. White Bear Lake has no streams feeding it and has to rely on local rainfall to maintain the water level and loss of water is primarily from evaporation. When it was determined that rainfall averages had not dropped significantly, other reasons have been looked at. One in particular was the possibility that there was some sort of 'hole' in the lake bottom that was the problem. Another was that a dewatering project a few miles away had somehow contributed to the loss of water.



From the 1900's until 1977, water was pumped into White Bear Lake (augmentation) from 12" wells in the county beach area up to a maximum rate of 5200 G.P.M. A maximum of 2551 million gallons were pumped in 1932 or 3.56 feet over the entire acreage of the lake. If you go north on the walking path, you will see a round brick building that housed one of the pumps. I am told that there was also another one that has been removed. Restarting the pumps has been discussed, but the MN DNR no longer allows pumping to maintain lake levels. During the winter of 2010/2011 the possibility of dumping the large snowfalls we were experiencing onto the ice from roads and parking lots was discussed, but the amount of snow needed to raise the lake even a small amount was determined to be more that could be hauled in economically. Another possibility discussed was to divert water from other lakes or the Mississippi river. These were rejected due to high cost, time necessary to construct diversions, and the possibility that numerous invasive species would be introduced to the lake.



One very recent theory that has gained momentum is that the White Bear area has experienced a 'micro-drought'. It is thought that the local rainfall had been much less than recorded by the nearby Vadnais Lake weather station, but no data could be found to support that possibility.



More recently, studies have focused on the SE portion of the lake where depths drop to about 80 feet. On July 11, the United States Geological Survey launched a drone submarine to study the deepest part of the lake. The purpose is to determine the relationship between the lake at the nearby underwater aquifers. Local divers have been interviewed to determine where cold spots might be that would indicate underwater springs the feed the lake. Results will be presented in a draft report in February 2012 and a final report in September 2012.

Here are some pictures of the Ecomapper in action taken by Jared Trost, USGS, Mounds View, MN. (Used with permission)



With the large areas of lakebed being exposed, a whole new set of issues have surfaced. One is ownership. Below is the Minnesota DNR's position:



General DNR Guidelines
--A very general "rule of thumb" is that the shoreline property owner's rights follow the water level up and down.
--The public normally has no right to use the shoreline or dry lake bed unless the adjoining shoreline is already in public ownership
--Landowners cannot fill, grade, build structures and otherwise alter the topography of the dry lakebed. This type of activity is strictly regulated through the DNR Division of Waters permit program

Facts
--White Bear Lake is designated as one of 5,480 "meandered" lakes in Minnesota.
--The land inside the "meander line" of the lake has not been assigned to a particular owner
--The lake bed is jointly owned by all of the landowners surrounding the lake

Summary
--The public does not have the right to use the dry lakebed area in front of a private lakeshore owner's property
--Private lakeshore owners do not have the right to fill, grade, build structures (including fences, and boundary structures) or alter the dry lakebed



Where has the water gone? And will it return naturally? Looks like we will be waiting be another year to find out.



To log this Earthcache, please do the following:

1)From the posted coordinates, walk out to the current waterline and email greywolfandwildrice@gmail.com the distance in feet shown on your GPS of where the shoreline is on the date of your visit. If it has rained recently, you made need to do a little wading to get to the shoreline. (In the winter, plan to bring a shovel to find the ice)

Note: If the distance is more than 528 feet, you may need to change your GPS's display so it displays 'feet' after reaching 528 feet. Also, don't bother to try and take the measurement from an aerial view. I'll know if you used that, as it is much different.

2) Describe your observations as to whether the water level is returning to normal or continuing to decline.

3) Look around GZ and you will see signs of where the normal water level has been. Take an approximate measurement from the posted coordinates to the normal shoreline. (Visible with moderate levels of snowfall. You may need to poke around a bit.)

4) Optional: Post a picture of the dry lakebed from GZ.

Grey Wolf's Stamp of Approval.
This Earthcache is located in a White Bear Lake City park with posted hours. It is your responsibility to be aware of and adhere to any hours of operation. Logs indicating caching outside of those hours will be deleted.

Additional Hints (No hints available.)



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