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<br />( <br /> <br />o <br />o <br />("") <br />~ <br />P- <br />~ <br /> <br />( <br /> <br />l. <br /> <br />Objectives: <br />Characterize water quality of different flow releases from Navajo Dam and <br />determine its impact on tailwater fisheries. <br /> <br />Methods: <br />The study area will be that portion of the San Juan River beginning at the <br />outflow' of Navajo Dam to the U. S. Highway 64 bridge .at Blanco, New Mexico. <br />There will be five collection sites for water samples: immediately below the <br />release of the dam; at the end of the "Special Trout Water" section of the river <br />(3.75 miles downstream); at the Aztec (State Highway 173) bridge; at the State <br />land section just downstream of the confluence of the San Juan and Pump Canyon <br />Arroyo; and at the U. S. Highway 64 bridge at Blanco. The need for addition or <br />deletion of sites will be determined as the results of the laboratory analyses <br />samples are obtained. <br /> <br />A monthly water sample will be taken at each site. Additional samples will be <br />taken at periods of changing flows while the dam is being operated to mimic the <br />natural hydrograph. The samples will be sent to the Soil and Water Testing <br />Laboratory at New Mexico Stace University or the State Laboratory Division in <br />Albuquerque for analysis. <br /> <br />Each sample will be analyzed for total filterable residue (dissolved solids), <br />turbidity (suspended solids) , alkalinity (as CaC03) , carbonate, sulfate, nitrate, <br />total hardness (as CaC03), sodium, potassium, calcium, magnesitun, iron manganese, <br />total phosphorous, and total nitrogen. While collections are being made, on-site <br />measurements of dissolved oxygen, temperature, conductivity, pH, salinity, and <br />nitrogen saturation will also be made. <br /> <br />When nitrogen supersaturation levels are detected, additional measurements will <br />be made at smaller distance intervals to determine how far downstream altered <br />levels occur and how rapidly the nitrogen dissipates. <br /> <br />At the completion of the first year of sampling, a summary of findings will be <br />submitted along with recommendations for further study. It is envisioned that <br />1-2 years of sampling will be sufficient for characterization of water quality <br />during periods of lower flows. Subsequently, some additional sampling may be <br />required during periods of high releases. <br /> <br />ANGLER USE AND CATCH SURVEYS <br /> <br />Background: <br />Estimates of angler use and catch rates are commonly used to measure the quality <br />of fishing on a particular water. These types of data have been collected for <br />several years as part of a Federal Aid in Fishers Restoration project on the San <br />Juan River. Angler pressure counts on the river indicate that the fishery is <br />increasing in popularity every year. Catch data indicate that a good- to- <br />excellent catch rate is consistently provided by the fishery. The main factors <br />contributing to the popularity of the fishery are probably the good-to-excellent <br />catch rate and the large size of the fish. Cursory examination of catch rates <br />and angler use for the first two years following high water releases of 5,000 cfs <br />in 2981 indicate a dramatic increase in both beginning soon after the return of <br />lower flows of 600 cfs. This suggests that the catch rates and access to the <br />river by wading' was' good at this time. During'higher releases, Kelly (1984) <br />found angler use to drop until low flows returned, probably as a result of <br />decreased access to much of the river during higher flows. <br /> <br />A22 <br />