To review existing techniques available for flood estimation in ungauged small rural and urban catchments and suggest a preferred technique or suggest further research (Phase 1).
Phase 1 will review the present methods for small catchments, recommend interim procedures if appropriate, and assess a range of possible future applicable methods. These methods might include various simple methods, FEH-type methods, hybrid models, and continuous simulation models. The suggested outcomes from Phase 1 will then be used as a basis for the development of new techniques for flood estimation in ungauged small catchments (Phase 2). The findings of the report and its recommendations (Phase 1) will be used by all hydrologists and engineers requiring flood estimates for small catchments.
Phase 2 will analyse datasets, develop techniques, and produce tools to enable reliable flood estimation for: small rural and urban catchments, changes in flood response due to urbanisation, flood peaks alone, and flood hydrographs. If Phase 1 suggest any new methods should be developed in Phase 2 then they should:
a) be simple to use, so that they can be applied to relatively low-cost studies
b) apply over a range of catchment types so that there are no artificial breakpoints, with associated discontinuities in results (e.g. as catchment urbanisation increases and it moves from one class to another)
c) be based on analysis of reliable high flow data
d) be based on sound science
e) be robust to uncertainties in catchment characteristics