Temperature - European Investment Bank

WEST AFRICAN POWER POOL (WAPP) PÖYRY ENERGY LTD.
Mount Coffee HPP ESIA and RAP 2012-09-18
ESIA Report Page 82
Another way of calculating is through the Morpho Edaphic Index, MEI= water
conductivity / average depth of the reservoir (Handerson and Welcomme, 1974 cited by
Welcomme et Barley, 1998); in this case, the formula stands as follows:
Y= 23.2�MEI.
There is no indication of the average water depth in available documents; this parameter
is of course lower than the main dam height at spillway level, i.e. 18.3m. An average
hypothetical depth half of this level, i.e. 9 m has been considered. The estimated
production would be
Y=23.2�75/9 = 70 kg/ha; for the 8.1 km 2 reservoir, this equates 70 x 8100 = 567tons.
Results are thus different according to the adopted formula; the actual figure may be in
between the two calculated data. Taking the average it would be around 370 tons, i.e.
about 1.5 times the production currently registered by upstream fishers at Mount Coffee.
With the afflux of more fishermen to exploit this additional resource, an improved
management strategy with the help of the Fisheries Bureau is needed. The average in
tropical waters is 2 to 4 fishermen per km 2 for sustainable exploitation. Over the 8 km 2
reservoir, this means a maximum of 20 professional fishermen should be authorised to
exercise in Mount Coffee reservoir (in addition to the already recorded native fishers).
The construction of a fish market with cold conservation facilities would be welcome to
improve the quality of fresh fish sold and overall nutritional welfare and health.
The Bureau of Fisheries may design production sheets where each fisherman would be
encouraged to record catch amounts and species composition. The responsible in charge
at the Bureau of Fisheries, M. Georges Weefar, has indicated his full availability to
animate community management of the new fishery to come, prevailing reasonable
functioning means are provided at start. With time, if all plans are implemented in due
form, sustainable management of the resource would not need any subsides. In joint
collaboration including LEC, the Bureau of Fisheries and fishermen leaders, minimum
needs for fishery resource protection should be realised: protection of restricted access
areas (from 1000 m upstream to 500 m downstream of the main dam); periodic transfer
of anadromous species from downstream to upstream; participation of fishers to stock
assessment and establishment of fishing regulation (permits with provisions on total
acceptable capture, periodic fishing closure, etc.).
11.5 Mitigation Measures
11.5.1 Mitigation Measures Related to Natural Habitats and Biodiversity
� Protecting fish biodiversity by securing protected zones with restricted access
near the dam (500 m downstream 1000 m upstream of the dam sites) and
insuring stock reinforcement of selected fish species adopting a partnership
approach involving native fishers.
� Fish transfer from downstream of the dam to the reservoir and vice versa. In
general it can be stated that, given the height of less than 20 m which the fish
would have to overcome a fish pass facility would be possible to implement, but it
should only be recommended based on sound scientific data, which are currently
lacking. Fish passes have been developed mainly in North America and Europe
for a very limited number of target species, mainly salmonides and clupeids. In