Cooperator Meeting for the Data Program Operated by the U.S. Geological Survey June 15-17, 22, 25 2004

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Attachment 4 DRAFT -- IDEALIZED STATEWIDE STREAM - WATER - QUALITY NETWORK AND PROPOSED PRIORITIZATION PLAN FOR ACTIVE WATER - QUALITY SITES A priority science goal of the USGS has been to establish a statewide surface -water quality network that would provide information to describe spatial and temporal variations in water - quality conditions at key locations in all major river basins throughout Colorado. An initial step toward the realization of this goal is the development of an idealized statewide water - quality network. The idealized network includes locations where water - quality data currently are being collected as well as locations where data currently are NOT being collected. The primary focus of this idealized network is the major streams and tributaries in each major basin. Information gathered from the operation of this network would be acquired using consistent methods and protocols throughout the processes of: preparation for field activity; field data - collection, sample preservation, and transport; laboratory analyses; data quality assurance, review, and initial summarization; and final data storage and archiving. For purposes of the idealized statewide water - quality network, the major river basins in Colorado were defined as the North Platte, South Platte, Arkansas, Rio Grande, San Juan, Animas, Dolores, Gunnison, Colorado, White, and Yampa. Major tributaries were defined as those tributaries contributing more than 20 percent of the mean annual mainstem discharge immediately downstream from the confluence or contributing a load of a constituent of concern (COC) that has a significant effect on COC concentrations or loads in the mainstem downstream from the confluence. Key site locations within each major basin were determined by selecting: (1) a site on the mainstem that represented the quality of water flowing out of the State; (2) mainstem sites downstream from the confluence of major tributaries; (3) sites on major tributaries near the confluence with the mainstem; (4) sites near the headwaters of the mainstem and major tributaries that represent background conditions; and (5) additional sites on the mainstem and major tributaries where substantial water - quality changes occur or may occur in the next 15 years (judgment based on current understanding of potential changes to the hydrologic system that could affect water quality). This included locations where major water - quality impacts could occur, such as reservoir outflows, major diversion points, upstream and downstream boundaries of large areas of land -use (agriculture, mining, urban) that could affect water - quality, and downstream from major point sources. Because streamflow is important in understanding spatial and temporal variations in water - quality, wherever possible, idealized water - quality network sites were located at existing streamflow gages. This concept paper provides a rationale that, in initial application by USGS staff, identified about 150 "key locations." Currently, the USGS is monitoring water - quality at about a third of the locations indicated in the idealized network. The other two thirds represent sites where we believe it appropriate for the USGS to do monitoring, but where we currently have no funding to do so. If the funding- constrained environment in which we now operate persists for years into the future, we believe it may be increasingly important and appropriate for the USGS to place a priority on the support of water - quality data - collection activities that best support the goals of the idealized network. In addition to development of a proposed idealized statewide water - quality network, we have developed initial concepts for a potential ranking scheme for prioritization of FMF investments for active stream water - quality monitoring sites. The ranking scheme provides differing scores for sites that: (1) Are a part of the idealized statewide network, (2) Support a watershed -scale water - quality network, and (3) Provide data to describe water - quality conditions in a local stream reach. Again, this draft concept and ranking scheme was only recently developed by USGS staff and will be presented at the June meetings for initial discussion with our cooperators.