National Engineering Handbook:
Section 4 - Hydrology
Author: USDA Soil Conservation Service (SCS)
Natural Resources Conservation Service (NRCS)
"This section of the engineering handbook contains methods and examples for
studying the hydrology of watersheds and for solving special hydrologic problems that
arise in planning, evaluating, and design of soil and water conservation and flood
prevention measures, including structures for water use, control, and disposal."
NEH-4 is a "must have" reference for any engineer involved in hydrology.
While the size (2" thick) may be intimidating, it contains authoritative
information on many central topics including: