Integrated watershed management is required to ensure the reasonable use of resources and reconcile interactions among natural and human systems. In the present study, an interval fuzzy multiobjective programming (IFMOP) method was used to solve an integrated watershed management problem. Based on system analysis, an IFMOP model suitable for a lake watershed system İFMOPLWS\ was developed and applied to the Lake Qionghai watershed in China. Scenario analysis and an interactive approach were used in the solution process. In this manner, various system components were incorporated into one framework for holistic consideration and optimization. Integrality and uncertainty, as well as the multiobjective and dynamic characteristics of the watershed system, were well addressed. Using two scenarios, two planning schemes were generated. Agriculture, tourism, macroeconomics, cropland use, water supply, forest coverage, soil erosion, and water pollution were fully interpreted and compared to identify a preferable planning alternative for local agencies. This study showed that the IFMOPLWS is a powerful tool for integrated watershed management planning and can provide a solid base for sustainable watershed management.}
The size distribution of aerosol chemical compositions was studied over a 2-week period in August 2001 at three locations (one urban and two semi-rural) in the Lower Fraser Valley (LFV) of British Columbia, Canada. The size distributions varied diurnally and were bimodal with a pronounced peak at about 0.3-0.55 mu m (accumulation mode) and SO42- 2-7 mu m (coarse mode). Generally, on an equivalent basis, the aerosol was dominated by SO42- (balanced by NH4+) in the accumulation mode range; SO42- often exhibited a diurnal variation that was primarily the result of fog deposition overnight and photochemical formation during the day. SO42- in the 3.1-6.2 mu m particles was mostly of marine origin. Most of the smaller particle SO42- was from anthropogenic sources and it is estimated that about 75% of the SO42- in the smaller particles were due to secondary processes. Oxalate, C2O42-, although at low concentrations (generally < 0.1 SO42- displayed a bi-modal size distribution, the accumulation mode being similar to SO42- and the coarse mode peaking at 4 1-1.8 mu m. Frequently at night, there was also a significant increase in NO3- in the accumulation mode that is attributed to the co-condensation of gas phase NH3 + HNO3 to form aerosol NO3- and the reactive uptake of N2O5 onto aerosols. In the coarse mode, the sea salt Cl- was frequently deficient relative to Na+ yet accompanied by a corresponding increase in NO3-; this was attributed to reaction of NO3- precursors (e.g., HNO3 and N2O5) with sea salt aerosol Cl-. (c) 2006 Elsevier Ltd. All rights reserved.