There are many freely available resources for hydrology education that I use in my teaching. I have linked a few of these below, to share with others:

Books:

• Rainfall Runoff Processes – Dave Tarboton (link)
• HydroInformatics – JP Gannon (link)
• Statistical Methods in Water Resources – Dennis R. Helsel, Robert M. Hirsch, Karen R. Ryberg, Stacey A. Archfield, and Edward J. Gilroy (link)

Tools and Apps:

• StreamStats (watershed delineation, land cover, regression equations) – USGS (link)
• Storm Runoff Simulation – Stroud Water Research Center (link)
• Model My Watershed (monthly water balance simulation and more) – Stroud Water Research Center (link)
• HBV Model Calibration for Worldwide Watersheds – JP Gannon (link)
• Ping Pong Unit Hydrograph – Rod Lammers (link)
• Web Soil Survey – USDA (link)
• SoilWeb (visual soil mapping – great for in the field) – UC Davis Soil Resource Lab (link)
• Climate Toolbox – Applied Climate Science Lab at UC Merced (link)

Videos:

• Access my videos for my classes (Surveying and Land Development, Water Resources Engineering, Hydrology) here – link