THE USE OF RADAR ALTIMETRY IN THE MAPPING OF A RESERVOIR 
by P.G. MOTT, B.A., A. M.I.C. E., F.R.I.C.S.. 
  
IN APRIL 1958, the Electricity Corporationof Nigeria, together withthe Federal 
and Northern RegionGovernments of Nigeria appointed Balfour Beatty & Co.Ltd. and 
NEDECO (the Dutch Consulting Engineers) jointly to investigate the feasibility of con- 
trolling the Niger at or upstream of Jebba for the purpose of power production, irriga- 
tion, navigation and flood control. 
Inthe latter partof 1958 some preliminary mapping was carriedoutfrom exis ting 
R, A.F. and NigerianGovernment photography of a possible dam site at Jebba and a 
reservoir above it. The results of this mapping were embodied in a Feas ibility Report 
which showed that a reservoir of sufficient capacity to control the river would be most 
economically provided by a dam located about 60 miles upstream of Jebba, The Feasi- 
bility Report was accepted by the Clients and a further and more detailed inves tigation 
was put in hand, 
Consequently, in July 1959, HuntingSurveys Limited, who had carried out the 
preliminary survey, were commissioned to prepare large-scale photogrammetric 
plans of dam sites at Kurwasa and Donko and to produce a 1/50, 000 scale map 
with contours at 20ft. vertical intervals covering a reservoir area of approximately 
1,500 square miles upstream of Kurwasa. 
To enable the new development to be commissioned in time to meet the rising demand 
for electricity supply before further large-scale thermal stations became necessary,the 
report on the detailed investigation was required during 1960. This meant that the com= 
pleted reservoir plans had to be in the hands of the engineers not later than February 1960, 
  
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KADUNA