Florinsky, Igor 
  
International cooperation should focus on exchanging jointly gathered data. This paper addresses the 
potential role of remotely obtained geo-information of river basins, shows some examples and the 
type of information what can be assesses, and discusses opportunities to utilize existing international 
space programs and databases better. 
2 Need for an accounting and monitoring system 
The irrigation sector is by environmentalists often regarded as inefficient, with huge amounts of water 
being wasted. This is somewhat short-visioned, as leaking and percolating water supplements aquifers 
and often or flow back to the lower laying river valley. It is ultimately somebody’s else water 
resource. Water in river basins is recycled both naturally and man-induced and this decreases the 
water losses (Keller and Keller, 1995). Recapturing irrigation losses through groundwater extraction 
of industries or by means of seepage towards wetlands are examples of depleting left overs of 
irrigation water diversions. The river should be seen as a central, unifying feature at the heart of a 
region, with the capacity to recycle water. Consequently, linkages between sources, uses and re-uses 
must thus be fully understood to appraise system losses, efficiency and possibilities of water savings 
(Perry, 1999). Saving irrigation water can thus be detrimental for industries, who rely on sufficient 
groundwater quantities. 
Proper water accounts support the appraisal of room for improving the productivity of water in a river 
basin. Water accounting is a basically new dimension to the water balance as it describes by whom 
the water is used and provides insights how water can be made more productive and economically 
rational (Molden and Sakthivadivel, 1999). Water accounting addresses issues such as water storage, 
flow committed to neighboring areas, water consumed by environments, water consumed by native 
vegetation, crop consumptive use leading to food production, depletion due to industrial producers 
and non-beneficial use of water such as soil evaporation. The depletion of water in a river basin is 
according to water accounting diverted into processes and non-processes. An example is given in Fig. 
1 based on the hydrological year 1998 of a drainage basin in Kenya. It shows that most water is 
consumed by native vegetation and natural forests. The total amount of depleted water is a large 
fraction of the gross inflow, which implies that little water flows out from this basin. Most water is 
however depleted by native vegetation such as low productive rangeland and bushland (606 million 
m”). Despite the inhabitants view on water resources use, most crop consumptive use occurs in the 
rainfed agricultural fields being located uphill far away from the villages. Rainfed crops consume with 
517 million m? seven times more water than the irrigated crops in the vicinity of the lake. The 
irrigated farms create also substantial employment and is good for Kenya's export. This demonstrates 
the advantages of thinking in the basin context and the need of accounts to understand what happens. 
  
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 441