Lake Level & Temperature 
United States Geological Survey (USGS) websites provides data on Iowa Great Lakes lake water level and water temperature. WEST LAKE OKOBOJI – data is taken at the Lakeside Laboratory in Millers Bay of West Lake Okoboji in Wahpeton, IA. The lake level and water temperature for East Okoboji, Lower Gar, Upper Gar, and Minnewashta should be similar since these lakes are interconnected with West Lake Okoboji. For West Lake data see website: http://ia.waterdata.usgs.gov/nwis/uv?06604200 For 730 Day Data Capability To determine the water level in inches compared to crest level – at which point water will flow over the dam at the bottom end of Lower Gar use the following formula: Subtract 4.04 from the given Gage Height (in feet) and then multiply that difference times 12. The resulting number is the number of inches that the water is low (if the figure is a negative number). Or how much higher than the dam if the water is flowing over (if the figure is a positive number). Example: (3.47 – 4.04) x 12 = 6.84 This means that that West Lake Okoboji must rise 6.8 inches before water will run over the dam at the South end of Lower Gar Lake that controls the lake level of West Okoboji, East Okoboji, Lower Gar, Upper Gar, and Minnewashta. SPIRIT LAKE – data is taken at Marble Beach State Park on the West shore of Big Spirit Lake. For Big Spirit Lake data see website http://ia.waterdata.usgs.gov/nwis/uv?06604000 For 730 Day Data Capability To determine the water level in inches compared to crest level – at which point water will flow over the dam at the Spillway at the bottom end of Big Spirit Lake use the following formula: Subtract 14.15 from the given Gage Height (in feet) and then multiply that difference times 12. The resulting number is the number of inches that the water is low (if the figure is a negative number). Or how much higher than the dam if the water is flowing over (if the figure is a positive number). Example: (13.46 – 14.15) x 12 = 8.28 This means that Big Spirit Lake must rise 8.3 inches before water will run over the spillway.

