Terrain constraints to urban land use : the case of Enugu, Nigeria

The quest for the best way to grapple with a myriacl of topographical
hurdles in the process of urhan land use management in Enugu motivated
this work. TI1e ernpirical investigation startecl with air photo-interpretation
and proceeded through field worJ< involving pedo-geomorpho:Jogical
and morphometric examination of the landscape.
Statistically and logically verifieè field information revealed
a high degree of terrain irregularities and hence the existence of
serious terrain constraints to urban land uses. The Enugu .Master Plan
aUempi io guide. urban planning process,
was seen as a planned, concertedlbut. unfortunately~ its neglect of
detailed geological and geomoJ.1lhologica1 datais a serious clefect.
The issue of slooe instabili ty and colJ apse of urban buildings
generated much concern. Our sub-soil investigation revealed a sequence
of over 50% clayey materials at a depth of 120cm helow the irround
surface. Gi ven the area' s l, SOOnun-annual rainfall, a li thology wi th
significant clayey strata sets the stage for a violent·operation of
catenary processes necessitated by surficial overlancl flow. In.teraction
of the catenary and surficial processes-explains slope instahility
and collapse of buildings found in the study area, while the hazard
is perpetrated by wrong land use allocation and encroachment upon
the green verges,
Unprecedented rncreases in bu_il t-up · areas are helcl to be responsihlPfor
decreasing infiltration, increased runoff and consequent erosion
and inu'llation over parts of the area. ln order to obvia te such