Florinsky, Igor 
  
   
  
  
Interception 231 — 1 
- Native vegetation 606 
* Swamps 48 
* Natural forest 403 
* Wildlife 2 
* Economic Forest 17 
  
  
  
Ire 
  
Fig. 1: Water accounts for the Lake Naivasha drainage basin during 1998, Kenya. The numbers 
present million m! yr? (data withdrawn from Salah, 1999) 
Conflict prevention is perhaps, the most important water management strategy for the 21* century. A 
regional cooperation on water issues and comparison between fellow states in a basin requires a 
standardized description of the water flows and the resulting processing emerging from that. One 
possible way of promoting a climate of confidence and favourable political will is by database 
building and deriving the water accounts subsequently from that. It must be admitted that nobody has 
reliable data related to water resources conditions, as data gathering and definition procedures greatly 
differ. We are plagued by insufficient data on water resources, just as we are plagued by insufficient 
water (Bastiaanssen, 1999). Satellite measurements can therefore have a significant contribution, and 
this aspect is grossly underestimated. 
3 Geo-information for all stakeholders 
3.1 Remote sensing and GIS 
Trust and faith in international river basin water resources management increases if rainfall, diverted 
water, soil moisture, crop evapotranspiration and plant growth data is collected at a range of scales, is 
adequate, available and accessible. It must be admitted that in a relatively short time span, 
hydrologists cannot diagnose the water accounts at the regional scale if hydrological data is improper 
or incomplete. It requires several months or even years by professionals to thoroughly quantify or 
model the hydrological processes and cycles in a river basin using other parties data. Satellite data can 
form an attractive alternative to numerical models. 
Satellites provide objective data for database building, which is politically neutral and cannot be 
manipulated. Satellite measurements reflect the land surface features and the observable landscape 
patterns culminated from socio-economical development, prevailing jurisdiction, agricultural 
practices, hydrological processes and irrigation management, apart from its original geological 
formation processes. Because of being direct measurements, satellite observations are often more 
reliable than secondary data. For instance, the irrigated area in the Gediz River Basin in Western 
  
442 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.