3 III.
Methodology
The methodology of this research study consists in literature
review focused the causes of the degradation of Lake Azuei watershed causing
impacts on its ecological balance. To achieve this, we will be collecting
information on the study area (soil, climate, topography, land use) and on the
physico-chemical parameters of Lake Azuei.
3.1 Geology
Lake Azuei constitutes a closed depression, a remnant of
inlets which occupied the plain of the Cul-de-Sac probably during the
Pleistocene (Quaternary) between the mountain
of in Trou d'eau and the Massif de la Selle.
The explanation for the formation of the lake has been assigned by
Woodring et al, 1924, a deposition of alluvial sediments from
the surrounding mountains. This lake is located in an alluvial plain bordered
by mountain ranges mostly carbonate, ground and karstified (landscapes lapiaz)
coral limestone and basalt, with variable topography (Pierre,
2008). It is at a distance about 30 km from the Bay of Port-au-Prince.
Its functioning is related to rainfall and its power by the torrential waters
and karst springs emerging from the massive and very bottom of the lake. The
original side of the bank of the lake is about 20 m, the highest point between
the lakeshore and coastline of the Bay of Port-au-Prince reached 38m where a
vertical drop of 18 m.
3.2 Prevailing Winds
The waters of Lake Azuei are constantly under the influence
steady winds of about 18 to 36 km / h. The prevailing winds are from the
Dominican Republic. During hurricanes, winds raise waves of up to two meters
amplitude (Michel, 2011).
3.3 The rainfall in the study area
The operation of the Lake Azuei is related to rainfall (600 mm
annual average) and its power by the torrential waters and springs emerging
from the massive karst and the lake bottom. During 2007, rainfall measured at
meteorological stations in the Ministère de l'agriculture, des
ressources naturelles et du développement rural
(MARNDR ) at Thomaseau gave 1900 mm against 499 to 800 mm
traditional, three times the average rainfall in the area.
The abundant rainfall in the chain of Trou d'Eau (North side)
is caused the appearance of many sources in the bottom of the Lake Azuei.
According to some experts, the karst structure of Trou d'Eau mountains would
have facilitated the infiltration of rainwater that accumulates in a layer of
clay below and cause the emergence of several underground sources or
underground rivers that would discharge into the Lake Azuei temporarily.
Graph I: Jimani Station Average Monthly Precipitation
(Romero and Poteau, 2011)
3.4 The watersheds of Lake Azuei
The watersheds of Lake Azuei consists of two slopes karstic
mountain ranges (Woodring et al, 1924): the chain of Trou d'eau and the Massif
de la Selle. It is the eastern extension of the chain of Matheux and a branch
of the Sierra de Neiba in Dominican Republic. The chain of Selle is a mountain
range located at south of Haiti. It extends to the Dominican Republic under the
name chain of Baoruco. The lake drains the southern slopes of the chain of Trou
d'Eau from which originate the majority of its sources. It also drains some of
the water that comes from the North Slope of the chain of Selle.
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