376 
Figure 1. Study area as part of Eastern Kenya, 
including Landsat mosaic of june '75, band 7. 
ble for irrigation. The strategy of opening up and 
incorporating the Lower Tana River area includes the 
establishment of large scale irrigation schemes and 
the utilization of Tana River water for the genera 
tion of elecricity by the construction of reservoirs 
in the middle reaches of the River. This policy 
objective is being pursued vigorously. 
In the development scenario outlined above the beha 
viour of the flooded river in the floodplain is felt 
as an outstanding constraint. It creates difficul 
ties of accessibility, damages infrastructure and in 
general impedes these development efforts. 
A major problem for these development efforts of land 
in the lower Tana River is the way in which the land 
is held and used by the traditional communities 
inhabiting the area, of which very little is known, 
in official records. Small sedentary communities live 
by growing rice and maize on basin lands and levees, 
mainly relying on flood water which comes once or 
twice a year. Practices related to agriculture 
include cutting down and burning of forest, digging 
of channels from the river to the shainbas, pumping of 
water and excavation of canals for irrigation. In 
the midst of the agricultural communities and around 
them land is occupied by groups of pastoralists, 
keeping cattle in combination with various other 
animals such as sheep, goats, donkeys and camels. 
The main pastoral groups are nomadic, migrating 
between different parts of the floodplain or between 
the riverine and outlying lands in different seasons 
of the year. 
1.3 Objectives of the described study 
The land use in the study area is of a very complex 
nature given the relationship between this land use 
and a highly dynamic river and riverine environment. 
The consequences of changes in land use, due to the 
implementation of irrigation schemes or changes in 
the hydraulic regime due to the construction of the 
hydro-electric power dams are not all that easy to 
analyse given the nature of the environment. 
It is therefore important to carry out an inventory 
of land utilization types (land utilization types), 
with emphasis on the relation between the land utili 
zation types and the hydraulic regime. 
The TRMS study yields results on expected changes in 
the morphology of the river. These results can be 
combined with the results of the inventory and des 
cription of the "hydro-environmental land utilization 
types". 
The objective of the study component on which this 
article reports can be summarized as the testing of 
low-cost remote sensing techniques in the inventory 
of land utilization types in the remote and inacces 
sible floodplains of the Tana River. 
The use of low-cost remote sensing techniques was 
required given the limited budget of the study. The 
budget also did not allow a quantitative analysis 
(with a satisfacory amount of data and field sam 
ples), but this was not felt as a serious constraint 
given the objective and the much more information 
yielding inventory than imagined possible during the 
start of the TRMS. 
This article reports on the methodology using micro 
light aircraft as a platform for vertical and oblique 
aerial photography which was of great use in the 
inventory, together with Landsat-imagery and existing 
small-scale aerial photography. It also presents some 
results of the inventory of land utilization types in 
relation to the hydraulic regime of the river and of 
course the physiography and climate of the riverine 
lands. 
2. Methodology 
2.1 Land utilization types 
It is assumed that traditional land use patterns bind 
together the information concerning the climate, the 
soil, the river and the history and the capacity of 
the people to develop or improve their situation. 
From this assumption and the high spatial variability 
within the floodplains it follows that land utiliza 
tion types can be described for many different cases. 
However the limited study budget and the demonstra 
tion character of the project did not allow a tho 
rough inventory of all these land utilization types, 
therefore a generalization was performed after the 
collection of all study data. This generalisation 
resulted in four broad land utilization types, with a 
however consistent relation between land use and 
hydraulics. 
The description of these land utilization types is 
based on data collected during different fieldwork 
periods and the study of existing literature, 
Landsat-imagery and existing aerial photographs. The 
fieldwork consisted of three periods in which obser 
vations were made during the different seasons, du 
ring floods and during periods of drought. The tec 
hniques for data collection in the project were the 
use of interviews, descriptions of vegetation and 
soils, and the use of a microlight aircraft as a 
platform for vertical and oblique aerial photography 
as well as visual reconnaissance. 
2.2 Use of existing information, aerial photography 
and satellite imagery 
Literature of the study area exists albeit in 
scattered and separate hoards. This information has 
been reviewed prior to the collection of additional 
data. The literature covers topics such as policy 
and planning, physiography, human population and 
settlements, climate, wildlife and ecology, soils, 
land use , water utilization and productivity. Howe 
ver, the data in the literature do not always provide 
a consistent starting data base. 
For instance do the population data of the national 
census of 1979 not contain a breakdown for riverine 
and nonriverine areas in the Tana River District, 
neither do they contain the geographical distribution 
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