[Slide index], c. 1940s

The hundreds of slides that make up this subseries are visual depictions of the groundwater studies found in the earlier series. Significantly represented are Kiowa Creek, the San Luis Valley, and the South Platte artificial recharge project. Also included are a significant number of slides on well drilling and general irrigation structures and methods. Notably, a card index provides important information about the dates and contents of many of the slides. The original order, alphabetic by folder title, is maintained, with some slides found elsewhere in the collection inserted accordingly.