Water-Quality Data Analysis of the Upper Gunnison River Watershed, Colorado, 1989–99 By Jason J. Gurdak, Adrienne I. Greve, and Norman E. Spahr U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 02–4001 NATIONAL WATER-QUALITY ASSESSMENT PROGRAM Prepared in cooperation with the CITY OF GUNNISON COLORADO RIVER WATER CONSERVATION DISTRICT CRESTED BUTTE SOUTH METROPOLITAN DISTRICT GUNNISON COUNTY MOUNT CRESTED BUTTE WATER AND SANITATION DISTRICT NATIONAL PARK SERVICE TOWN OF CRESTED BUTTE UPPER GUNNISON RIVER WATER CONSERVANCY DISTRICT Denver, Colorado 2002 U.S. DEPARTMENT OF THE INTERIOR GALE A. NORTON, Secretary U.S. GEOLOGICAL SURVEY Charles G. Groat, Director The use of firm, trade, and brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. For additional information write to: Copies of this report can be purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Information Services Box 25046, Mail Stop 415 Box 25286 Denver Federal Center Denver Federal Center Denver, CO 80225–0046 Denver, CO 80225 FOREWORD The U.S. Geological Survey (USGS) is committed Each assessment is guided by a nationally consis- to serve the Nation with accurate and timely scientific tent study design and methods of sampling and analy- information that helps enhance and protect the overall sis. The assessments thereby build local knowledge quality of life, and facilitates effective management about water-quality issues and trends in a particular of water, biological, energy, and mineral resources. stream or aquifer while providing an understanding (http://www.usgs.gov/). Information on the quality of how and why water quality varies regionally and of the Nation’s water resources is of critical interest to nationally. The consistent, multi-scale approach helps the USGS because it is so integrally linked to the long- to determine if certain types of water-quality issues are term availability of water that is clean and safe for isolated or pervasive, and allows direct comparisons of drinking and recreation and that is suitable for indus- how human activities and natural processes affect try, irrigation, and habitat for fish and wildlife. Esca- water quality and ecological health in the Nation’s lating population growth and increasing demands for diverse geographic and environmental settings. Com- the multiple water uses make water availability, now prehensive assessments on pesticides, nutrients, vola- measured in terms of quantity and quality, even more tile organic compounds, trace metals, and aquatic critical to the long-term sustainability of our commu- ecology are developed at the national scale through nities and ecosystems. comparative analysis of the Study-Unit findings. The USGS implemented the National Water- (http://water.usgs.gov/nawqa/natsyn.html). Quality Assessment (NAWQA) Program to support The USGS places high value on the communica- national, regional, and local information needs and tion and dissemination of credible, timely, and relevant decisions related to water-quality management and science so that the most recent and available knowl- policy. (http://water.usgs.gov/nawqa). Shaped by edge about water resources can be applied in manage- and coordinated with ongoing efforts of other Federal, ment and policy decisions. We hope this NAWQA State, and local agencies, the NAWQA Program is publication will provide you the needed insights and designed to answer: What is the condition of our information to meet your needs, and thereby foster Nation’s streams and ground water? How are the increased awareness and involvement in the protection conditions changing over time? How do natural fea- and restoration of our Nation’s waters. tures and human activities affect the quality of streams and ground water, and where are those effects most The NAWQA Program recognizes that a national pronounced? By combining information on water assessment by a single program cannot address all chemistry, physical characteristics, stream habitat, and water-resource issues of interest. External coordina- aquatic life, the NAWQA Program aims to provide tion at all levels is critical for a fully integrated science-based insights for current and emerging water understanding of watersheds and for cost-effective issues and priorities. NAWQA results can contribute to management, regulation, and conservation of our informed decisions that result in practical and effective Nation’s water resources. The Program, therefore, water-resource management and strategies that protect depends extensively on the advice, cooperation, and and restore water quality. information from other Federal, State, interstate, Since 1991, the NAWQA Program has imple- Tribal, and local agencies, non-government organiza- mented interdisciplinary assessments in more than 50 tions, industry, academia, and other stakeholder of the Nation’s most important river basins and aqui- groups. The assistance and suggestions of all are fers, referred to as Study Units. (http://water.usgs.gov/ greatly appreciated. nawqa/nawqamap.html). Collectively, these Study Units account for more than 60 percent of the overall water use and population served by public water supply, and are representative of the Nation’s major hydrologic landscapes, priority ecological resources, Robert M. Hirsch and agricultural, urban, and natural sources of Associate Director for Water contamination. FOREWORD III CONTENTS Foreword ................................................................................................................................................................................ III Abstract.................................................................................................................................................................................. 1 Introduction............................................................................................................................................................................ 2 Purpose and Scope....................................................................................................................................................... 4 Acknowledgments ....................................................................................................................................................... 4 Study Area ............................................................................................................................................................................. 4 Hydrology .................................................................................................................................................................... 6 Geology........................................................................................................................................................................ 6 Methods of Data Analysis ..................................................................................................................................................... 8 Data Sources ................................................................................................................................................................ 10 Data Quality Assurance ............................................................................................................................................... 10 Data Compilation and Comparison ............................................................................................................................. 10 Temporal Trend Analysis............................................................................................................................................. 11 Surface-Water Quality ........................................................................................................................................................... 12 Field Properties............................................................................................................................................................ 12 Major Ions.................................................................................................................................................................... 15 Nutrients ...................................................................................................................................................................... 17 Spatial Distribution and Comparison to State Standards................................................................................... 18 Temporal Trends ................................................................................................................................................ 18 Land-Use Comparison....................................................................................................................................... 22 Trace Elements............................................................................................................................................................. 24 Spatial Distribution and Comparison to State Standards................................................................................... 24 Temporal Trends ................................................................................................................................................ 28 Streambed Sediment .........................................................................................................................................