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Lake Bottom Study 1999 Home Page
Water Depth SUMMARY
R E C A P   of  1 9 9 9   D a t a    B Y   W A T E R   D E P T H   R A N G E
    A v e r a g e   D e p t h   o f Average % # in this # places Silt 
    Water Silt Silt Depth range More than Water
  10+ Feet 11.9 6.1 51.2% 32 1
  9 to 10 Feet 9.4 4.7 50.0% 6 0
  8 to 9 Feet 8.4 6.1 73.2% 21 8
  7 to 8 Feet 7.2 5.4 75.0% 52 11
  6 to 7 Feet 6.6 4.0 60.1% 56 8
  5 to 6 Feet 5.4 1.5 27.4% 28 0
  4 to 5 Feet 4.6 1.1 23.6% 24 0
        Totals 219 28

Silt Depth SUMMARY
R E C A P   of  1 9 9 9   D a t a    B Y   S I L T   D E P T H    R A N G E
    A v e r a g e   D e p t h   o f Average % # in this # places Silt 
    Silt Water Silt Depth range More than Water
  10+ Ft Silt 11.2 9.7 115.6% 8 6
  9 to 10 Ft Silt 9.5 9.2 103.6% 6 4
  8 to 9 Ft Silt 8.3 9.8 85.1% 13 4
  7 to 8 Ft Silt 7.5 8.2 91.5% 21 14
  6 to 7 Ft Silt 6.4 8.1 79.3% 14 0
  5 to 6 Ft Silt 5.5 7.3 75.2% 25 0
  4 to 5 Ft Silt 4.6 7.8 58.4% 19 0
  3 to 4 Ft Silt 3.4 7.8 43.6% 17 0
  2 to 3 Ft Silt 2.3 7.0 33.6% 27 0
  1 to 2 Ft Silt 1.5 6.7 21.7% 42 0
  < 1 ft Silt 0.6 5.3 11.1% 27 0
        Totals 219 28
 
                Hard Bottom Depth SUMMARY
R E C A P   of  1 9 9 9   D a t a    B Y   HARD  BOTTOM   D E P T H    R A N G E
      A v e r a g e   D e p t h   o f Average % # in this # places Silt 
    Hard Bottom Silt Water Silt Depth range More than Water
  0 to 2 Ft: 1576 no data          
  2 to 4 Ft: 1574 no data          
  4 to 6 Ft: 1572 5.4 0.7 4.7 14.5% 25 0
  6 to 8 Ft: 1568 7.0 1.4 5.6 25.5% 33 0
  8 to10 Ft: 1566 9.2 2.4 6.8 35.7% 29 0
  10 to 12 Ft: 1564 11.2 3.8 7.4 50.9% 37 0
  12 to 14 Ft: 1562 13.0 5.2 7.8 65.9% 38 2
  14 to 16  Ft: 1560 15.0 7.1 7.9 89.5% 23 15
  16 to 18 Ft: 1558 17.2 7.4 9.7 76.2% 10 5
  18 to 20 Ft: 1556 19.1 8.9 10.2 87.0% 12 5
  20 to 22 Ft: 1554 20.9 8.6 12.3 70.3% 10 4
  23 to 24 Ft: 1552 23.8 11.7 12.1 96.7% 2 1
            219 31


Bottom Views to CHOOSE FROM
View Illustrated Silt
Depths
View Illustrated Cross Sections
 of lake bottom along
six(6)  North-
South lines
across the lake
North - South Cross Sections
 Click on a letter image to view the detail bottom at that cross section
 
Lake Cross Section A   
Lake Cross Section B
Lake Cross Section C
  
Lake Cross Section D
Lake Cross Section E
Lake Cross Section F
View Illustrated Cross Sections
 of Four Deep
 Spots
Cross Sections of Deep Spots 
Click on an image to view the detail bottom  cross sections of that Deep Spot
Centennial Park offshore
Deep Spot

 

Vogt Park
 Offshore
Deep Spot

Sunset Park
 Offshore
Deep Spot

Sailboard Beach
Offshore
Deep Spot

View Illustrated Hard
Bottom
Depths
Hard Bottom Depth Views 
Click on an image to view the a larger version
 
View Illustrated Data in several ways
Water Depth Sequence
this shows the test results in depth ranges as images side-by-side
   
 

 

Silt Depth Sequence
this shows the test result in silt depth ranges as images side-by-side
       
Test Shot # Sequence
 view test result by number
   
Hard Bottom Sequence
View test result  by common hard bottom depths side-by-side


METHOD
There were 219 places that were tested through the winter ice to determine water depth and where hard bottom began that produced valid data. There were a few more test shots done on land that are left out of this presentation.

The method used was to press a pole against the bottom of the lake and determine where water ended and soil began ( soft stop) and then where solid bottom was found ( hard stop). This simple process was used to determine the depth of the water and the silt.

There was no way, with the 1999 study, to determine soil composition as had been done on the 1944, 1952, 1956 and some of the 1977 bottom studies.

This method was not as precise as the core boring methods used in 1944, 1952, 1956 and some of  the 1977 study, but it was much less expensive.

All water depths in this presentation are against the dam runover level of 1576 feet above sea level, not the water surface level on the day of the study. 

OBSERVATIONS:
There were more test sites studied on this bottom study than any of the other years.

Over 10% of the test sites showed more silt than water depth at that point.

No tests were done in water less than 4 feet deep.

There were grouping of tests done on the four areas of the lake where deep areas exists.

There were six groupings of tests done in a North-South pattern across the lake at several points, following the same cross-section pattern as had been done in several previous studies.

This study was sponsored by the Southwest Minnesota Fishing Club, Nobles County Environmental Services Department, Okabena-Ocheda Watershed District and Nobles Soil and Water Conservation District.

Labor was provided by: The Southwest Minnesota Fishing Club, The Nobles Soil and Water Conservation District, Nobles County Environmental Services Department

The Okabena-Ocheda Watershed District paid for the survey
The Okabena-Ocheda-Bella Clean Water Partnership Board may have paid part of the cost of publishing the brochure
Zieske Land Surveying of Windom, MN was paid to do the survey work, Houston Engineering of Fargo, ND was hired to draw the topographic map of the lake bottom for the brochure

The Excel spreadsheet analysis, graphic images and presentation were created by Bob Rohrer in 2007
  Original Data Collection Sheets 1999 Lake Map ( originally 24' x 3.5")
Source These are written results of each test from the day of the testing in 1999 for water depth and hard bottom
 
Water Depth 1 2 3 4 5 6 7 8
Hard Bottom 1 2 3 4 5 6 7 8
Each document is an image approx 100 kb
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Designed by Rohrer & Associates 2007