Dam spillway level may not reflect lake level

After an email discussion with the Public Works Director we theorized that the level of the water at the spillway may not be a true representation for the whole lake. When the water in the lake reaches the spillway it begins to swell from the force of the current. The amount of swell may vary depending on the volume of water traveling over the dam.
I will be measuring the lake level deviation from normal from my dock which 3/4 mile away from the dam. Since there is no established normal level I used watermarks from surrounding docks as guides. The log is viewable on the right hand side of this blog. An entry of zero in the lake column means the lake is at the established normal level. The dam column represents the level at the dam spillway, 3" - 6" is the established safe level there. The Public Works Director will be using comparing these values against the dam spillway log. If there is a significant difference between the two values, I assume corrective action would be taken for judging the lakes true level.