A n EE P 
2. Close together with the river basin development the vegetation development is 
connected.Large parts are still close forests(miombo) especially within the less 
undulated topography. Here subsistance farming is sparcely found. In the lower 
lands vegetation is poor and the remaining shrubs are often not higher than l m. 
They are dying during the dry periods which last nearly 4 to 5 months every year 
under the influence of the southern monsun. 
The intensive shamba cultivation in these areas is responsible for a low shrub: 
and grass cover. Partly a regeneration of the vegetation is not possible.. 
A population increase,caused by better health services automatically rises the 
shamba extensions. Ecology protecting subsi tance farming of the past will chan- 
ge to rapid exploitation of the still fertile soils which are not developing 
other vegetation than a poor grass cover within the rainy and changing periods. 
The vicious circle of erosion and soil exploitation of spontanous extensive far- 
ming is unavoidable. 
3. The rainfall intensities are quite stable over the entire year and falling 
within the period from october to march. Rainfall duration is often 1 to 2 hours 
accompanied by sudden havy rain storms with an immediate runoff,low infiltration 
at the beginning and a steep ascending branch of the runoff hydrograph and high 
tractive forces. 1 to 2 cm soil cover losses can be observed during those rain- 
storms. 
The transportation energy of the satellite observed sediment load can be conclu- 
ded from the change of sediment amount,strongly correlated with the size and the 
amount of the catchment area. 
The decrease of the vegetation canopy leads to a higher heating up of the soils 
and a quicker convection of the heated air which is mixed in 1 km height with 
the cooler air coming from the sea and causes increased clouds and following 
rain storms. This phenomenon is preferably observable in regions with a progres- 
sive desertification like in the northern and southern parts of Dar-es-Salaam, 
from the Usambara-Mountains to the Rufiji-River-Delta. 
If no erosion protection is taken desertification will spread out in Southern 
Tanzania as well as in other parts of the country. 
Evaporation is depending on wind speed more than on temperature and humidity 
as the latter is quite constant within the vegetated zones and only varies with- 
in the wilted vegetation and on bare soil surfaces during a day. 
Where the evaporation and evapotranspiration,detectable by near infrared field 
observations together with satellite reflectances,are strongly varying during a 
day higher bare soil amounts and shrub vegetation is present. 
The low evaporating and highly heated soils and shrubs are leading to the men- 
tioned rain storms washing away the soils. 
Erosion and sedimentation is finally the end stage of every badland development 
in these regions. 
8. Cost of periodic monitoring 
The costs can be divided into two categories: 
1. the at once costs 
2. the current costs 
To the at once costs belongs: the purchase of a radiometer,the camera equipment 
with different mounting accessories,the densitometer,a manual digitizer or a 
digital tablet with a desk or pocket computer connection. 
All together can be figured out presently to 5000 to 10 000 dollars. 
The current costs are for: purchase and processing of images,films and develo- 
ping materials,aerial photography and machine processed images. 
Figured for one monitoring mission this is up to 1000 to 2000 dollars. 
If a mission is to be untertaken all half a year at the end or beginning of the 
two tropical seasons,the current yearly costs are around 5000 dollars. 
Compared with one mission project with high sophisticated technology and very 
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