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! ;1 Heat budget quantification of modeling has been performed to a limited degree by the Upper Colorado Region of the Bureau of Rec1amation as part of preliminary studies for selective withdrawal feasibility. The extent of this modeling has been to determine the effects over a two- year period of selective withdrawal. A more elaborate approach to reservoir modeling is needed to determine heat budget effects over a longer period and to help quantify the relative effects of dam operations and those of other hydrodynamic, hydrologic, and climatologic processes. This modeling effort would be very valuable to test the effects of various operational scenarios on short and long-term water quality conditions in Lake Powell. " " ~ Biological sampling is performed routinely as a component of the current Lake Powell Water Quality Monitoring Program. Several analyses are performed at the forebay and other selected stations on the reservoir. Chlorophyll concentrations are measured at the reservoir surface to describe the overall levels of primary productivity from photosynthesizing plankton. Discrete samples are taken near the surface for analysis of phytoplankton concentration and community structure. Composite samples are collected by vertical tows through the water column for analysis of zooplankton concentration and community structure. This information is used to describe long-term and seasonal changes in primary and secondary productivity and describe the type and amount of these organisms in Glen Canyon Dam releases. No work is currently being performed on macrophytes, periphytes, or macro-invertebrates. Evaluation of these shallow- water organisms is more appropriately addressed with a side channel and embayment water quality assessment. .' " f- .rot. l:' " No work is currently being performed by GCMRC to determine levels of selenium in reservoir water, sediment, or biota. Work is planned, however, on a Colorado River basin-wide selenium study to be performed by the Upper Colorado Region of the Bureau ofReclarnation. It is expected that Lake Powell selenium issues will be addressed by BOR and that it will be linked with the existing Lake Powell Water Quality Monitoring Program. '" j": ...:" ;:: A final component of the Lake Powell Water Quality Monitoring Program is the development of extensive science synthesis and database management systems for water quality information, This project supports the Lake Powell water quality management objective and addresses the GCMRC objective of establishing a comprehensive information technology program. These science and data assessments will be directly linked with other hydrologic and water quality databases and will be available by means of direct access and data warehousing products by various means including World Wide Web access. Its development has been ongoing and is being enhanced as other information technology programs progress. " ."-:": ..", 2~. "-. .'~ ~' .; ~': Costs associated with this program include operating and maintenance for the sampling vessel, maintenance and repair of instrumentation and other equipment, analysis of chemical and biological samples, and travel and salary costs for personnel. The research vessels and all necessary equipment is outdated, and will need refurbishment or replacement in the next 2 to 3 years. .~, " ./. ,',,' The vessel from which the majority of sampling is performed is a 31-foot Uniflite Sedan, which has been in use on Lake Powell for water quality sampling and other activities since 1970. The primary instrument for collecting water quality profiles is a Hydrolab H2O/Surveyor 3. Chemical analyses of water samples is currently being performed by Reclamation's Water and Soil Laboratory in Denver, CO. Chlorophyll is analyzed by Reclamation's Boulder City water quality lab. A crew of 4-6 people is commonly used for quarterly reservoir surveys, comprising two GCMRC staff 1imnologists, an employee from Reclamation's Upper Colorado Region, an employee of the Glen Canyon National Recreation Area, and other ancillary personnel as needed.