OREGON, USA, ECOLOGICAL REGIONS AND SUBREGIONS FOR WATER-QUALITY MANAGEMENT

To aid in producing a protection and management strategy for the freshwater resources of Oregon, USA, we have defined an initial set of ecological regions and sub-regions of the state that organize the spatial similarities and differences in water quality. We have delineated and mapped these subregions using existing maps of ecological regions, maps of selected environmental characteristics, remote sensing imagery, and descriptive literature. To help in interpreting the resulting map, a unique approach to mapping regions is used. We have described the relative widths of regional boundaries, and we ranked the characteristics used in determining them. Water quality managers in Oregon intend to apply these subregions as an organizational framework for data display and reporting, prioritizing monitoring and pollution control strategies, developing biological criteria for water quality standards, and developing other regional water quality management approaches.