LOW-FLOW CHARACTERISTICS OF MISSISSIPPI STREAMS by E.J. Tharpe Prepared by the United States Geological Survey in cooperation with the Mississippi Board of Water Commissioners 1975 Bulletin 75-1 TABLE OF CONTENTS Abstract Introduction     Purpose and scope     Acknowledgment Records available Low-flow characteristics Analysis of the station data Regulated streams Presentation of data     Downstream order and station number     Data for continuous-record gaging stations     Data for partial-record gaging stations Areal variability of low flows Estimates at ungaged sites Selected references FIGURES 1. Map showing mean annual precipitation and runoff 2. Map showing location of stream-gaging stations 3. Graph showing magnitude and frequency of annual 7-day average low flow for the Big Black River at Pickens, Miss 4. Graph relating discharges of the Big Black River near Vaiden and near Pickens, Miss. 5. Map showing variation in low-flow runoff TABLES 1. Data for continuous-record gaging stations 2. Data for partial-record gaging stations ABSTRACT Low-flow data for 443 sites on streams in Mississippi provide the basis for calculation of minimum 7-day average flows, and annual 7-day average low flows with 2-and 10-year recurrence intervals. These flow characteristics, particularly the annual 7-day average low flows with a 10-year recurrence interval are used in Mississippi by State and Federal agencies, along with minimum observed discharges, in determining the availability of flow for water supply and waste assimilation and in administering water laws and regulations. Low-flow characteristics of long-term stations were computed by a Log-Pearson Type III probability analysis of available data. For partial-record and short-term continous-record sites these characteristics were defined from a correlation based upon flows concurrently observed at the site and at a nearby long-term station. At ungaged sites, low-flow characteristics may be approximated either by interpolation between gaged sites or from a map showing areas of near-uniform low-flow yields. These areas which are delineated on the basis of geologic and hydrologic similarities, have yields ranging from 0 to more that 0.5 cubic foot per secong per square mile, or 0.014 cubic metres per second per square kilometre of drainage area. LizardTech's Djvu plug-in is needed to view these reports. CLICK HERE TO VIEW THE ENTIRE REPORT For questions or comments, contact K. Van Wilson.