Looking for advice for a lake here in Iowa called big creek. Mainly looking for pre spawn tips if possible. https://www.iowadnr.gov/Portals/idnr/uploads/fish/maps/BIC77.pdf Is a map of the lake. 

5' evelation map lakes don't show a lot of details but does have shaded areas that indicate depth changes. My quick initial look for pre spawn is the upper 2/3rd of this lake above the narrows at the State Park using the 10' line for structure definations. Any lines that have sharp 90 turns are usually something man made and of interest. Several humps off shore are of interest. The major main lake points near the bay or coves are of interest.

The lower 1/3rd west shore has a few areas of interest like the channel leading towards the outlet canal should hold some bass. The mid section has some interest hook shape points with adjacent coves that could hold staging pre spawners.

Will take a closer look if time permits. 

Tom

What is the water temperature???