The Blue Lake and Lewis Lake surveys included topographic surveying of the surface, photogrammetry, and bathymetric surveys of Blue Lake and Lewis Lake to collect data to determine total storage volume, useable volume, and dead pool volume of each lake. Additionally, the invert of the Blue Lake water tunnel was surveyed. A remote controlled sonar equipped boat was used to measure the lake bottom elevations. Del-Mont obtained quality, usable information without draining the lakes.