Evaluation of Streamflow Requirements for Habitat Protection by Comparison to Streamflow Characteristics at Index Streamflow-Gaging Stations in Southern New England By David S. Armstrong, Gene W. Parker, and Todd A. Richards (Massachusetts Division of Fisheries and Wildlife) In cooperation with the Massachusetts Department of Conservation and Recreation; and the Massachusetts Department of Fisheries, Wildlife, and Environmental Law Enforcement, Massachusetts Division of Fisheries and Wildlife Water-Resources Investigations Report 03-4332 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior Gale A. Norton, Secretary U.S. Geological Survey Charles G. Groat, Director U.S. Geological Survey, Reston, Virginia: 2004 For sale by U.S. Geological Survey, Information Services Box 25286, Denver Federal Center Denver, CO 80225 For more information about the USGS and its products: Telephone: 1-888-ASK-USGS World Wide Web: http://www.usgs.gov/ Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. iii Contents Abstract. 1 Introduction . 2 Purpose and Scope . 2 Description of Study Area . 2 Previous Studies. 4 Relations among Flow Regimes, Stream Processes, and Aquatic Habitat . 5 Acknowledgments. 5 Streamflow Characteristics at Index Streamflow-Gaging Stations in Southern New England . 5 Index Stations . 6 Selection Criteria . 6 Basin Characteristics. 6 Fish-Community Sampling and Assessment . 6 Flow Statistics for Index Stations . 10 Flow-Duration Statistics . 11 Low-Flow Statistics . 19 Characterization of Flow Regimes for Index Stations . 19 Classification of Index Stations. 19 Flow Regimes for Index-Station Groups . 22 Streamflow Variability for Groups of Index Stations . 24 Streamflow Requirements for Habitat Protection at Index Stations in Southern New England. 27 Methods for Determining Streamflow Requirements Based on Hydrologic Records . 28 Range of Variability Approach. 28 Tennant Method . 29 New England Aquatic-Base-Flow Method . 29 Streamflow Requirements Determined from Hydrologic Records . 30 Range of Variability Approach. 30 Tennant Method . 30 New England Aquatic-Base-Flow Method . 34 Methods for Determining Streamflow Requirements Based on Hydraulic Ratings . 34 Water-Surface-Profile Modeling . 34 Wetted-Perimeter Method. 36 R2Cross Method . 36 Streamflow Requirements Determined from Hydraulic Ratings . 38 Wetted-Perimeter Method. 38 R2Cross Method . 39 Evaluation of Streamflow Requirements. 41 Suggestions for Further Study . 44 Summary and Conclusions. 44 References Cited. 45 iv Appendix 1: Annual Flow-Duration Curves for 10 Index Streamflow-Gaging Stations in southern New England . 59 Appendix 2: Procedures for Application of the Wetted-Perimeter Method . 67 Appendix 3: Study-Site Descriptions , Documentation of Input, Calibration Data for HEC-RAS Models, and Hydraulic Variables Simulated by Calibrated HEC-RAS Models for 10 Index Streamflow-Gaging Stations in Southern New England . 71 Figures 1. Map showing location of index stations, and riffle study sites, southern New England . 3 2. Photograph showing Massachusetts Division of Fisheries and Wildlife and U.S. Geological Survey personnel identifying, counting, and measuring fish collected by electrofishing. 9 3, 4. Graphs showing: 3. Annual flow-duration curves for Wood River near Arcadia, RI (01117800), and Green River at Williamstown, MA (01333000), for water years 1976–2000. 13 4. August streamflows at the Sevenmile River near Spencer, MA (01175670): A, August daily mean hydrographs for 1990, 1978, and 1977 water years; B, August monthly fduration curves for 1990, 1978, and 1977 water years; and C, August median monthly duration curve, for water year 1976–2000 . 15 5. Map showing classification of index streamflow-gaging stations in southern New England . 23 6–8. Graphs showing: 6. Regionalized medians of the 50-percent monthly flow durations, normalized by drainage area, for index stations grouped by A, geographic region, November– May; and B, magnitude of median 50-percent monthly flow durations, June–October . 24 7. Median monthly flow durations, normalized by drainage area, and the interquartile range about the 25-, 50-, and 75-percent monthly flow durations for June through October for the high- and low- median monthly flow-duration groups for index stations: A, June; B, July; C, August; D, September; and E, October. 25 8. Median of average daily discharge for n-day low-flow statistics, normalized by drainage area, for the high- and low-median monthly flow-duration groups, for index stations for water years 1976–2000 . 27 9. Schematic showing A, cross section of stream channel; and B, relation between wetted perimeter and discharge . 37 10. Graphs showing comparison of Range of Variability Approach flow-management targets, normalized by drainage area, to the 25th and 75th percentiles of the 50-percent monthly flow duration for the: A, low monthly flow-duration group; B, high monthly flow-duration group. 43 Tables 1. Locations, descriptions, and basin characteristics of index stations for flow statistics and determination of streamflow requirements in southern New England. 7 2. Scientific names and habitat-use classifications of fish in southern New England . 10 3. Percentages of fish in each habitat-use classification sampled in flowing reaches of several river basins in Massachusetts. 11 v 4. Location and descriptions of fish sampling stations, fish-sampling date, electrofishing methods and effort, reach length, reach width, and fish numbers and species for 10 rivers in Massachusetts . 12 5. Habitat-use classifications for reaches near 10 index stations in Massachusetts. 12 6. Median and interquartile ranges for 50-percent monthly flow-duration discharges (Q50), normalized by drainage area, for 23 index streamflow-gaging stations in southern New England for water years 1976–2000 . 16 7. Median and interquartile range for n-day low-flow statistics, normalized by drainage area, for 23 index stations in southern New England for water years 1976–2000 . ..