Geography:
 The
Gambia is situated in the Sahelian zone on the West
Coast of Africa. It is one of the smallest countries
in Africa (the smallest being Seychelles archipelago)
and has a total area of 11,300 square km, of which about
20 percent is described as wetland. The river runs from
east to west, dividing the country in two strips of
land 25 to 50 km wide and about 300 km long.
 The
country has a total boundary length of 820 km (510 mi),
of which 80 km (50 mi) is coastline. The River Gambia,
the country's major waterway, rises in Guinea and follows
a twisting path for about 1,600 km (1,000 mi) to the
sea.
 A
flat plateau of tertiary sandstone, capped with an infertile
ironstone crust, gently rises from 10- 15 m at the coast
to 100 m at 400 km inland. The rest of the catchments
consists of older worn Paleozoic and Pre-Cambrian rock
with a maximum height of about 1500 m in the Fouta Djallon.
Pleistocene and Holocene (Nouakchottian transgression)
exist along the coast, along the estuaries and in river
valleys.
The landscape two major geomorphologic units can be
distinguished between the uplands and the lowlands:
On the upland plateaus, weathered tropical soils are
found. These soils have low intrinsic fertility and
low water retention capacity, but their drainage conditions
are good. The plateau is intersected by watercourses
flowing downwards on the lowlands. These streams have
formed narrow fluvio colluvial valleys (Wulumbangos).
The lowlands include the floodplain of the River Gambia
in the Upper Valley, and tidal plains (Banta Faros)
in the Central Valley and Lower Valley. The soils of
the lowlands are flat, fine textured and poorly drained.
In the LV potentially acid sulphate soils occur, which
can become acidic soils unless water logging is prevented
by drainage.
Water Resources:
Outside salinity risk areas (Scott Wilson Kirkpatrick,
1993), freshwater can be found throughout The Gambia,
at depths ranging from 4 to 30 mbgl (metres below ground
level). In general, depths increase with proximity to
the border with Senegal. Groundwater recharge depends
on the quantity and spatial and temporal distribution
of rainfall, surface geology, and land use (Howard Humphreys
and Sons, 1974; Chow, 1964). Good quality surface water
within the country is only found in the eastern third
of the River Gambia. From June to December, freshwater
availability is boosted by flows from the middle and
upper Gambia River Basin areas. Low flows from January
to May are mostly sustained by local rainfall (Njie,
2002).
Natural Habitats:
The main feature of the land is predominantly Guinea
woodland savannah and Sahelian scrub with with mangroves
concentrated near the estuary of the River Gambia and
along its banks and Bolongs.
 The
vegetation is comprised of the Savannah type with shrub
and grass understoreys. Mangroves are found in the western
half of the country in the floodplains of the river
region. The cultivable land area is roughly 430,000
hectares, which is 38 percent of the total area. Back
in 2002 available arable land was 250,000 hectares,
while 5,000 hectares were under permanent crops. |
