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Controlling flooding levels using a spillway
Spillways are most appropriate for sites where there is a need to control the
frequency and amount of flooding. Instead of a breach,
tidal water enters the site on tides over a spillway built in the seawall. The
structure is effectively a broad crested weir. An advantage of this technique
is that the number of inundations a year can be controlled. The design height
of the spillway is determined by compiling a curve showing the tidal height
above which the corresponding frequency of desired flooding per annum is obtained.
Caption:
A simplified diagram of a spillway. Other examples are described in the more
general context of Regulated
Tidal Exchange in (Lamberth &
Haycock 2002).
| Guidance: One advantage of controlling flooding through a spillway
is that there is no need for the construction of an embankment to limit
the extent of the flooded area. The width of the spillway determines how
much water flows onto the site. |
References
Lamberth, C. & Haycock, N.
2002.
Regulated Tidal Exchange: An Intertidal Habitat Creation Technique. Report by Haycock Associates Limited, St. Albans.
RSPB and Environment Agency.
RSPB and Environment Agency.
RSPB and Environment Agency.
RSPB and Environment Agency.
Environment Agency and the Royal Society for the Protection of Birds.
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