1.   Purpose and objectives

     To examine and review those aspects of flood estimation methods and research most relevant to reservoir flood safety appraisals.

2.   Description

     This component is a report summarising a study of reservoir flood estimation techniques. It is mostly drawn on United Kingdom methods and experience, while selectively reviewing procedures and developments elsewhere. The report identifies currently recommended procedures and explores aspects of flood estimation and research particularly relevant to reservoir flood safety appraisals.

     Special topics discussed include:

     - sensitivity of flood estimates to the precise storm duration assumed;

     - seasonal variation in the Probable Maximum Flood (PMF);

     - 10,000-year flood estimates.

     Controversial topics such as the inclusion of snowmelt in PMF estimates and the incorporation of local data into reservoir design floods are also discussed.

     A new algorithm for `level-pool' flood routing is presented, along with detailed examples. Approximate formulae are considered for the peak- to-peak lag time and attenuation ratio associated with reservoir routing. Listings in FORTRAN are given for ROUTER (a reservoir routing program) and
a simple program for peak interpolation.

     The report contains more than 150 references, mostly post-dating the UK Flood Studies Report (NERC, 1975).

3.   Input

     Not applicable.

4.   Output

     Not applicable.

5.   Operational requirements and restrictions

     Not applicable.

6.   Form of presentation

     Report in English: Institute of Hydrology Report No 114, 87 pages, 9 figures, 29 tables, 2 program listings in FORTRAN.

7.   Operational experience

     Not applicable.

8.   Originator and technical support

     Institute of Hydrology, Wallingford.

9.   Availability

     From the HOMS National Reference Centre of the United Kingdom.

10.  Conditions on use

     Free of charge.