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ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS”, Bangkok, May 23-25, 2001 
produce less than 1/5 of total economic return in the basin area. 
At the same time, they generate significant nonpoint source 
pollution problems. Since agriculture has been developed to a 
matured level, and the related management measures can only 
partly mitigate the environmental problems, it is suggested that 
the agricultural activities and the related pollution concerns may 
not fluctuate with time so significantly as other activities (e.g. 
tourism and industries). As an example, Figure 7 presents the 
solution for vegetable farming. 
Figure 7 Planning for vegetable farming 
For industrial activities, cigarette industry contributes to the 
majority of regional economy with relatively low pollution 
potential. Food processing industry would be promoted since it is 
needed for supporting tourism development and for 
corresponding to improved living standard. Figure 8 shows 
planning for the food processing industry. For the other 
industries, pulp, chemical fibre and leather production generate 
large amounts of organic pollutants (with high COD 
concentrations) under the existing technologies. It is suggested 
they be significantly reduced or cut. For textile, paper and 
cement industries, it is recommended that their status would be 
flexible from short-term management point of view. Since the 
study system is now with demanding environmental conditions, a 
relatively conservative strategy may be desired. Therefore, from 
long-term planning point of view, it is suggested that those 
industries’ further development be limited. At the same time, 
development of high-tech industries with low or no pollution 
impacts would be encouraged 
alternative for this type of activity is to develop fish ponds out of 
the lake. Number of vessels for in-lake fishing and navigation 
should be limited to reduce direct sewage/waste discharge into 
the lake. Sanitary toilets should be installed within the existing 
vessels. Also, public lavatories with sanitary facilities should be 
constructed at docks for the vessels, with the sewage being 
collected and treated periodically. 
CONCLUSION 
(1) In this study, a hybrid GIS-supported watershed modeling 
system is developed for integrated planning of water pollution 
control in the Lake Erhai Basin. This system consists of three 
major components: database, modelbase, and user interface. 
The modelbase includes three aspects: (i) simulation models for 
bridging source/impact factors and the related water quantity and 
quality; (ii) an optimization model for compromising a variety of 
system objectives and generating desired decision alternatives; 
and (iii) post-modeling analysis for further trade-off analysis and 
risk assessment. The GIS technology is chosen as a basic tool 
throughout the modeling process. It allows smooth 
communication among the database, the models and the users. 
(2) An inexact-fuzzy multi-objective programming (IFMOP) model 
is developed as a planning tool. It can effectively reflect 
uncertain, interactive, and multiobjective features of the study 
system. The inexact solutions provide decision-makers with a 
flexible decision space, and are useful for further risk analysis. 
Three decision alternatives are generated by adjusting decision 
variable values within their solution intervals. 
(3) An important advantage of this study is its real-time feature. 
When environmental and socio-economic conditions are 
significantly changed in the future (e.g. when an unexpected 
large project is developed in the basin area two or three years 
later), the provided planning alternatives may become not 
applicable. Consequently, updated alternatives need to be 
provided. For the previous environmental planning, the provided 
reports may become useless, and a new planning project may 
have to be initiated again. In comparison, this study provides not 
only research reports for planning based on the existing 
information, but also a set of flexible computer software 
packages. Thus, when conditions are significantly changed in the 
future, local engineers/planners can input updated information 
into the computer-managed database, run the user-friendly 
modelling software, and obtain a new set of planning alternatives 
through the provided graphic interfaces. 
cessing Industry 
—r caps mOST"""" 
Figure 8 Planning for food processing industry 
Net-cage fish culture should be cut due to its significant 
contribution to N and P pollution problems in the lake. An 
(4) This study is the first integrated environmental planning study 
in China. Comprehensively and quantitatively, it provides 
planning schemes based on development/application of a set of 
effective decision-support methodologies. The provide software 
and part of the recommended schemes have been used by the 
local authorities in their management practices. 
ACKNOWLEDGEMENT 
This research has been supported by the United Nations 
Environment Programme and the Natural Sciences and 
Engineering Research Council of Canada. 
REFERENCES 
Bicknell, B.R., et al. (1997), Hydrological Simulation Program- 
Fortran: User’s manual for version 11. USEPA, National 
Exposure Research Laboratory, EPA/600/R-97/080.