TITLE:
Prospects for Minimizing the Potential Environmental Impacts of the Hydro-Agricultural Dam of M’Bahiakro (Côte d’Ivoire)
AUTHORS:
Lazare Kouakou Kouassi, Innocent Kouassi Kouamé, Séraphin Kouakou Konan, Brou Dibi, Soumahoro Moussa, Diakaria Koné, Dago Gnakri
KEYWORDS:
Hydrology; Irrigation; Dam; Suspended Sediment; N’Zi River
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.5 No.9,
September
12,
2013
ABSTRACT:
This study aims at characterizing the physical environment and suggesting
solutions for a better management of the hydro-agricultural dam of M’Bahiakro
which is being constructed over the N’Zi River and is the first inflatable dam
in Cote d’Ivoire. In this
survey, data related to hydrology, characteristics of the dam and the irrigated
rice production area were obtained with the Water Resources Agency and the
National Office of Rice Development of Cote d’Ivoire. Physicochemical parameters
of the N’Zi River were collected seasonally at three monitoring stations. Results
showed that the N’Zi River is characterized by a high water level period from
April to November and a low water level period from November to April. The gap
between the low flows and the high flows is important (about 206 m3/s on average). The annual
average flow is 40 m3/s
with a standard deviation of 32.52 m3/s
and a variation coefficient of 0.88. The SAR average value (1.63) and the
average conductivity (78.44 μS/cm) showed that waters of the N’Zi River are of
high quality to be used for irrigation. Suspended sediment concentrations do
not present significant difference along the river. But the seasonal variations
are important; they are higher during the rainy seasons (45.8 mg/L on average)
than in the dry seasons (17.7 mg/L on average). The annual solid flux of the
N’Zi River is 41897 tons, i.e. 15810 m3 of
sediments. The annual sediment flux is important and can lead to high
depositions in the line-shaped reservoir of the dam and that calls for
attention to control the silting up of the reservoir. Great efforts concerning
interdisciplinary approaches, as well as extensive and intensive field work are
needed in order to better manage the hydro-agricultural dam of M’Bahiakro.