Hydrological Methodology Evolution for Runoff Estimations at Ungauged Sites

This review paper recites fundamentals of historical runoff estimation methodologies that were developed for ungauged drainage basins. Additionally, new approaches are also provided as extensions modern ones. Early calculations suggested towards the end 18th century, when there was no record availability rainfall or runoff. Some these have not been cited in scientific literature, but they frequently used by engineers practical hydrological different parts United States, especially Kansas. hydrologists aware shortcomings, hampered shortage reliable streamflow and data. These methods did consider recurrence intervals associated with designs, their drawbacks originated more from a useful hydrologic data rather than logical rational interconnection between causative resultant factors. With measured data, early studies considered daily total amounts design purposes, which continued until 1935 frequency maps published durations shorter 24 h. Frequency analysis advancement 1940s regional flood sites. The transition to frequency-based started 1950 onwards. It is main purpose this cite recent simple area rainfall, works. provides each approach so reader may become acquainted evolution studies.