Composite unit hydrograph
"Superposition of unit hydrographs of a large catchment with the beginning of rise times appropriately lagged by travel times from the outlets of the sub-areas to the outlet of the catchment." (United Nations Publications, 2013)
Sources
United Nations Publications. "Glossary of Shared Water Resources (English-Arabic): Technical, Socioeconomic and Legal Terminology." (2013). DOI:https://dx.doi.org/10.18356/70b462ce-en