History of hydrological modeling
Truckee River, one of the first rivers to have a comprehensive hydrological/water quality model. Source: Bruce C.Cooper
Hydrological modeling was undertaken to better understand the relationships between rainfall and runoff in the latter half of the 19th century in response to three main engineering problems: urban sewer design, land reclamation drainage systems design, and reservoir spillway design. It is conceivable however that these types of engineering problems date back to before the Roman Empire, and that planners of that time dealt with similar issues at smaller scales (see History of Hydrology).
The major goal of the first attempts at hydrological modeling was to estimate discharge. Many of the first models were based on empirical equations developed under unique conditions and used in applications under similar conditions. Some models used the rational method to encompass and predict runoff peaks. Early in the 20th century, hydrologists tried to improve the applicability of the rational method to large catchments with heterogeneous rainfall and catchment characteristics. The resulting unit hydrograph technique, using the principle of superposition, was introduced in the early 1930’s. This concept dominated hydrology for more than twenty-five years and is still in widespread use today. The unit hydrograph was the first model to estimate the entire shape of a hydrograph rather than simply hydrograph peak flow values.
During the 1950’s, hydrologists began developing conceptual models. The 1960’s brought the introduction of computers into hydrological modeling, enabling complex water problems to be simulated as complete systems. The first comprehensive hydrologic computer model, the Stanford Watershed Model, was developed at Stanford University. Real-time forecasting rainfall-runoff models were developed in the late 1970’s and 1980’s in response to the need of warnings in flood-prone areas and as a tool for reservoirs and hydraulic structures management.
Surface runoff models
Generally surface runoff models were developed later than river channel models, partly due to the delayed interest in analyzing contaminant runoff from non-point sources. The surface runoff element, which allows assessment of sediment, fertilizer, herbicide, pesticide and other chemical contaminants. Building on the research of Horton, the unit hydrograph theory was developed by Dooge in 1959. It required the presence of the National Environmental Policy Act and kindred other national legislation to provide the impetus to integrate water chemistry to hydrological modeling. In the 1970s the United States Environmental Protection Agency began developing a series of water quality models in response to requirements of the Clean Water Act. An example of these efforts was developed at the Southeast Water Laboratory, one of the first attempts to calibrate a surface runoff model with field data for a variety of chemical contaminants.
Further reading
- P.E.O’Connell. 1991. A historical perspective. In Recent Advances in the Modeling of Hydrologic Systems. Kluwer, Dordrecht. pp. 3-30.
- N.H.Crawford and R.K.Linsley. 1966. Digital simulation in hydrology: Stanford Watershed Model IV, Technical Report No.39 Stanford University, Palo Alto, Ca
- J.C.I.Dooge. 1959. Parameterization of hydrologic processes, JSC Study Conference on Land Surface Processes in Atmospheric General Circulation Models, 243-284 (1959)
- C.M.Hogan, Leda Patmore, Gary Latshaw, Harry Seidman et al. 1973. Computer modeling of pesticide transport in soil for five instrumented watersheds, U.S. Environmental Protection Agency, Southeast Water Laboratory, Athens, Ga. by ESL Inc., Sunnyvale, California
- C.Michael Hogan, Marc Papineau et al. 1987. Development of a dynamic water quality simulation model for the Truckee River, Earth Metrics Inc., Environmental Protection Agency Technology Series, Washington D.C.
- D.F. Manzer and M.P. Barnett.1962. Analysis by Simulation: Programming techniques for a High-Speed Digital Computer, in Arthur Maas et al, Design of Water Resource Systems, pp. 324--390, Harvard University Press, Cambridge, MA
- V.P.Singh. 1995. Watershed Modeling. In Computer Models of Watershed Hydrology. ed. Singh, V.P. Colorado: Water Resources Publications. pp. 1-22.
- E.Todini. 1988. Rainfall-runoff modeling - past, present, and future. Journal of Hydrology. 100: 341- 352.
- USEPA. 1991. Guidance for water quality-based decisions: The TMDL process, EPA 440/4-91-001. U.S. Environmental Protection Agency, Office of Water, Washington, DC
