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Data Series 305

Prepared in cooperation with the Southern Ute Tribe and the Bureau of Reclamation

Water-Quality Data Collected from Vallecito Reservoir, Its Inflows and Outflow, Southwestern Colorado, 1999–2002

By Anthony J. Ranalli

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Data Series 305
PDF (2.9 MB)
Abstract

The Pine River Watershed Stakeholders Group was created in December 1997 to allow local participation in addressing water-quality issues in Los Piños River watershed, including Vallecito Reservoir in southwestern Colorado. One water-quality issue identified by the stakeholder group is to increase the understanding of the current water quality of Vallecito Reservoir, its two major inflows, and its outflow. The U.S. Geological Survey (USGS), in cooperation with volunteers from the Pine River Watershed Stakeholders Group and the U.S. Environmental Protection Agency (USEPA), U.S. Bureau of Reclamation (BOR), Colorado Department of Public Health and Environment (CDPHE), Pine River Irrigation District, Southern Ute Tribe, San Juan Basin Health Department, and San Juan Resource Conservation and Development, collected water-quality samples from Vallecito Reservoir, its two major inflows, and its outflow between August 1999 and November 2002 at about monthly intervals from April through November. The water-quality samples were analyzed for total and dissolved metals (aluminum, arsenic, cadmium, copper, chromium, iron, lead, manganese, mercury, nickel, silver, and zinc), dissolved major ions (calcium, magnesium, sodium, potassium, chloride, bicarbonate, and sulfate), dissolved silica, dissolved organic carbon (DOC), ultraviolet (UV) absorbance at 254 and 280 nanometers, nutrients (total organic nitrogen, dissolved organic nitrogen, dissolved ammonia, dissolved nitrate, total phosphorus, dissolved phosphorus, and orthophosphate), chlorophyll-a (reservoir only), and suspended sediment (inlets to the reservoir only). Measurements of field properties (pH, specific conductance, water temperature, and dissolved oxygen) were also made at each sampling site each time a water-quality sample was collected.

This report documents (1) sampling sites and times of sample collection, (2) sample-collection methods, (3) laboratory analytical methods, and (4) responsibilities of each agency/group involved in the project. The report also provides the environmental and quality-control data collected during the project and provides an interpretation of the quality-control data (field blanks and field duplicates) to assess the quality of the environmental data. This report provides a baseline data set against which future changes in water quality can be assessed.

Version 1.0

Posted January 2008


Suggested citation:

Ranalli, Anthony J., 2008, Water-quality data collected from Vallecito Reservoir, its inflows and outflow, southwestern Colorado, 1992–2002: U.S. Geological Survey Data Series 305, 76 p.



Contents

Abstract

Introduction

Purpose and Scope

Sampling Locations, Dates of Collection, and Project Responsibilities

Methods of Data Collection

Stream Samples and Field Properties

Reservoir Samples and Field Properties

Sample Processing and Shipment

Laboratory Analysis

Field Blank and Field Replicate Data Collection and Interpretation

Analysis of Field Blanks

Analysis of Field Replicates

Analysis of pH and Specific Conductance Standard Reference Samples by the Hydrolab

Summary

Acknowlegments

References Cited

Appendix

 


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