Laserfiche WebLink
<br />0024G3 <br /> <br />11 <br /> <br />APPENDIX B <br /> <br />GCMRC Lake Powell Water Quality Monitoring Program <br /> <br />The current Lake Powell Water Quality Monitoring Program is linked closely with <br />other water quality monitoring programs below Glen Canyon Dam, which address other <br />downstream management objectives. The Lake Powell program consists of monthly surveys <br />of the forebay above Glen Canyon Dam and quarterly surveys of the entire reservoir. The <br />objective of the program is to characterize the chemical and physical parameters of the water <br />in Lake Powell to determine the effects of Glen Canyon Dam operations and separate these <br />effects from other natural processes affecting reservoir water quality. This program is linked <br />to a long-term record of similar measurements collected by the Bureau of Reclamation and <br />Glen Canyon Environmental Studies since 1965, which describes the entire history of Lake <br />Powell since its impoundment by Glen Canyon Dam. <br /> <br />Pending formal approval by the Adaptive Management Work Group, this program <br />represents an ongoing water quality monitoring effort by GCMRC that would remain in place <br />throughout the five-year period of this work plan. <br /> <br />Monitoring activities are designed to meet the stated information needs of Management <br />Objective 1 for Lake Powell Water Quality: <br /> <br />MO 1: Lake Powell Water Qmolity Prevent unacceptable effects on the water quality <br />(physical, chemical, biological) of Lake Powell due to dam operations and ensure that <br />fully informed AMWG decisions are possible both now and in the future. <br /> <br />Field activities include collecting a profIle of measurements throughout the water <br />column at each station for temperature, specific conductance (an indirect measure of salinity), <br />pH, dissolved oxygen, turbidity, and oxidation-reduction potential. This profile describes the <br />degree of stratification, or mixing, and the range of temperature, salinity, and dissolved <br />oxygen concentrations at a particular station. This information is used to describe the behavior <br />and fate of inflow currents, advective and convective mixing processes, and the effect of Glen <br />Canyon Dam withdrawal currents under different operational scenarios. It is also used to <br />characterize the overall quality of the reservoir as well as that of the major strata within the <br />reservoir. For example, monitoring of dissolved oxygen levels in the deepest stratum of the <br />reservoir, or hypolimnion, can be used to predict when significant levels of hydrogen sulfide <br />could occur. <br /> <br />In addition to the profIle of physical and chemical characteristics, several samples may <br />be collected at a station for further chemical analysis. Analysis of major cation and anion <br />concentration is performed to quantify the individual components of salinity and to identify the <br />origin of a parcel of water to further understand reservoir hydrodynamics. Analysis of <br /> <br />DRAFT - June 17, 1998 <br />