Following
an idea from a comment at one of my last post, concerning the groundwater
availability, I found the next project at the lake Chad.
"Advice on groundwater resources for the Lake Chad Basin
Commission" Again a cooperation between the LCBC and the BMZ (GIZ), but
this time with the additional help of the BGR. The project runs from July 2011
to June 2017 with a budget of 4 million €.
First of all, for a better understanding of the importance or potential
of groundwater, I start with a quotation from the LCBC website; “The Lake Chad
Basin is one of the largest sedimentary groundwater basins in Africa“ (LCBC).
But at the same time it is also one of the largest “closed” groundwater
basins, which means there are just inflows and no outflows. The inflows are provided from mainly
two river systems the Chari-Logone River, which provides up to 95% of the
inflow and ends into the southern pool and the Komandugu-Yobe River, which ends
into the northern pool. But most time of the year, the Komandugu-Yobe River
doesn’t even arrive at the lake and runs dry kilometres before. (GIWA regional43)
The
groundwater basin is divided into three main aquifers, “the upper Quaternary
(alluvial aquifer), the Lower Pliocene and the ‘Continental Terminal’
(Oligocene – Miocene) (both sands and sandstone)” (LCBC). The main recharge to
these aquifers is provided by surface waters and by the lake. Therefore, the
vulnerability is quite high.
Figure 6: BGR
„The
groundwater quality of the Quaternary phreatic aquifer is suitable for domestic
consumption of the local population and livestock. The Lower Pliocene Aquifer,
found at depths of about 250 m with average thickness of 60 m, is an artesian
aquifer intensively used in the Nigerian part of the basin. Although the
reserve of the Lower Pliocene Aquifer is unknown, the exploitation of this
aquifer is estimated at about 3 million cubic meters per year.“ (BGR)
The project aims to provide knowledge of sustainable use of the
groundwater and the trans boundary exchange of collected data between the
member states of the LCBC. The project is divided into two stages; the first
stage is all about collecting data, groundwater levels and the quality of the
water. The second stage concentrates more on creating a groundwater database and
giving the knowledge from stage one to LCBC experts, so that they can move on
by themselves. The project will finish by creating integrated water resources
management strategies. (LCBC)
Thank you for taking my thoughts from last two post. :) I think the cooperation between the two institutions are very important as you discussed in your previous post. The fortunate thing is, as you mentioned before, that the groundwater is a closed system (therefore not much loss through outflow), but this also might mean that pollutants from upstream of the surface inflows would accumulate into the system (like solutes carried by erosion taking place during intensive rainfall upstream / agricultural fertilizers). Also, in the case of sustainably managing the groundwater quantity and quality, I think that they need an alternative source of freshwater from somewhere else as well as managing efficient use of groundwater. I very much look forward to reading your next post soon. :)
AntwortenLöschenThe question of pollution and alternative water sources, I am hopefully going to answer in my next post :) Thank you, for the inspiration!
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