One of the key attributes of small reservoirs in many locations in the world is the unreliability (or
the absence) of up-to-date inventories. The evaluation of their potential at national or regional scales,
and the strategic planning of future infrastructure in selected areas, are dependant on accurate
information. It is important to have at disposition a synoptic perspective highlighting “where
reservoirs are”.
Burkina Faso is probably the West African country with the highest density of small reservoirs. As
elsewhere, the demand for the creation of new reservoirs remains constant. Neither the actual
distribution of small reservoirs nor the spatial dynamics associated with the construction of new
devices are available. Basic information regarding the status of small reservoirs i.e. their locations
and size remain to be gathered and shared.
Small reservoirs are artificially created aquatic ecosystems. Intrinsic factors such as size (depth)
determine their potential (e.g. capacity, biological productivity). But external driving pressures,
hereafter called contexts, ultimately control their effective properties (Cecchi 2007). Growing
populations and intensive use of watersheds may exert severe pressures that e.g. modify runoff or
stimulate eutrophication. Conversely the value of small reservoirs isolated in an area devoid of
people is questionable. Contexts, including human behavior, modulate their potential. It is useful to
locate reservoirs in response to the key drivers exerted by their environment.
A ‘pilot’ Atlas of Lakes and Reservoirs of Burkina Faso, called FasoMAB, has been developed to
fulfill these needs. Earlier versions of the atlas were developed to help to profile specific
interventions of the SRP in Burkina Faso, and first of all determine “where to work”. It was decided
to focus scientific activities in areas simultaneously characterized by high densities of populations
and high densities of reservoirs (hot spots). Administrative limits were first used to select these
areas, with departments (N=351) as finest grain (Fig. 1). Further refinements provided alternative
geographical perceptions of these hot spots. Using the grid of the Climatic Research Unit to pixelize
the country allowed a neutral identification of clusters of reservoirs; the use of a Digital Elevation
Model furnished a hydrographic perspective and allowed the identification of target basins.