Lake Okabena Bottom Studies

1956 Data Presented in Water Depth sequence

1956 water level at the time of the study was 1573.2, as designated on the chart below by the BLUE horizontal line at 1573.2. This study was done in a period of low water. The water level was 2.8 feet BELOW the dam runover level of 1576. Notice that over 90% ( 43 out of 49) of these were less than a water depth of four feet.

1956 Data Presented in SILT Depth sequence

This may be some help seeing the relationships between silt and depth or bottom characteristics. Over 70% of these show more silt than water depth. Those high silt places are denoted by the 1 pixel black border and light gray background.

1956 Data Presented in SOLID BOTTOM sequence

Solid bottom for a lake like this is usually designated as where hard clay begins. Typically a lake's solid bottom has probably been in the same place, undisturbed, since the last glacier, since it is only top soil, sand and gravel that move around.

However, in many cases, this 1956 study has did not go deep enough to establish where sand ends and clay begins. So, it is more difficult to establish where the bottom of the lake is on these borings. The borings where solid bottom was found are presented on the chart below first. These are followed by the borings that have sand bottoms which have were given a sand colored border to make it obvious that this boring never went below sand.

The lowest solid bottom was at 1553.2 feet above sea level (#18A).

The places where silt depth was greater than water depth are denoted by the 1 pixel black border and light gray background. Be aware that water level was 2.8 feet below dam runover point. This effects the interpretation of borings like #53 which, if the water level were at runover level could be 7.6 feet of water and thus, while it had more silt than water at the time of the 1956 study, it could have more water than silt if the water level were at dam runover level of 1576.

1956 Data Presented in boring # sequence

Bust 1952-56 lake bottom boring data out of frame to allow entire results to be printed

The 1952 and 1956 core borings of the bottom of West Lake Okabena were both documented on the same large lake map. This map and data came from files in the Soil Conservation District Office. The data was transferred to the attached spreadsheet for use here. The position of the numbers on this lake map correspond to the location of the core borings. The background view of the lake is a more recent satellite view of Worthington, not from the 1952-56 era.

Elevation above sea level is used to help make these studies comparable even though they were done when the water was at different levels.

The 1952 study ( boring numbers 1 to 14) was done when the water surface level was 1576.09 feet above sea level. The 1956 study (boring numbers 15 on) was done when the water surface level was 1573.2. The dam runover level is 1576 feet above sea level.