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Streamflow Measurements, Basin Characteristics, and Streamflow Statistics for Low-Flow Partial-Record Stations Operated in Massachusetts from 1989 Through 1996 By Kernell G. Ries, III Abstract length; mean basin slope; area of surficial stratified drift; area of wetlands; area of water bodies; and A network of 148 low-flow partial-record mean, maximum, and minimum basin elevation. stations was operated on streams in Massachusetts Station descriptions and calculated streamflow during the summers of 1989 through 1996. statistics are also included in the report for the 50 Streamflow measurements (including historical continuous gaging stations used in correlations measurements), measured basin characteristics, with the low-flow partial-record stations. and estimated streamflow statistics are provided in the report for each low-flow partial-record station. Also included for each station are location infor- INTRODUCTION mation, streamflow-gaging stations for which flows were correlated to those at the low-flow Streamflow statistics are useful for design and operation of reservoirs for water supply and partial-record station, years of operation, and hydroelectric generation, sewage-treatment facilities, remarks indicating human influences of stream- commercial and industrial facilities, agriculture, flows at the station. Three or four streamflow mea- maintenance of streamflows for fisheries and wildlife, surements were made each year for three years and recreational users. These statistics provide during times of low flow to obtain nine or ten mea- indications of reliability of water resources, especially surements for each station. Measured flows at the during times when water conservation practices are low-flow partial-record stations were correlated most likely to be needed to protect instream flow and with same-day mean flows at a nearby gaging other uses. In 1988, the U.S. Geological Survey station to estimate streamflow statistics for the (USGS) began the first of three studies to determine low-flow partial-record stations. The estimated streamflow statistics for Massachusetts streams. These streamflow statistics include the 99-, 98-, 97-, 95-, studies, done in cooperation with the Massachusetts 93-, 90-, 85-, 80-, 75-, 70-, 65-, 60-, 55-, and 50- Department of Environmental Management, Office of percent duration flows; the 7-day, 10- and 2-year Water Resources (MOWR), were referred to as the Basin Yield studies. Three reports have been published low flows; and the August median flow. Character- previously as a result of the Basin Yield studies (Ries, istics of the drainage basins for the stations that 1994a, 1994b, 1997). Each report describes regression theoretically relate to the response of the station to equations that were developed for use in estimating climatic variations were measured from digital streamflow statistics for sites on streams where no data map data by use of an automated geographic infor- are available, and provides basin characteristics and mation system procedure. Basin characteristics estimated streamflow statistics for selected stations. measured include drainage area; total stream The MOWR uses the information provided in the Introduction 1 reports to develop water management plans for the 27 During the third Basin Yield study (Ries, water-resources planning basins in the State. The 1997), but before data for all stations in the network completed plans are used by communities, regional were available, a regression equation was developed planners, and other State agencies to manage the water to predict the August median streamflow. The resources in the basins, and to make decisions analysis for this equation included 96 stations; 37 regarding permitting of new water withdrawals and were continuous streamflow-gaging stations and 59 interbasin transfers. were LFPR stations, of which 54 were part of the A network of low-flow partial-record (LFPR) network. This equation is applicable to ungaged stations was established at the beginning of the streams with a much larger range of basin first Basin Yield study and continued through the characteristics than the flow-duration equations second and third Basin Yield studies. Streamflow developed for the first study. measurements were collected systematically over a This report describes the network of 148 period of years at the LFPR stations, and were used to LFPR stations operated in Massachusetts as part estimate streamflow statistics for the stations. Selected of the Basin Yield studies between the summers basin characteristics were measured for the stations of 1989 and 1996. The description includes station from digital maps by use of a Geographic Information selection and operation of the network, selection System (GIS). The streamflow statistics and basin and measurement of basin characteristics, and characteristics determined for the LFPR stations were methods used to estimate the streamflow statistics. used to develop regression equations for predicting Streamflow measurements (including historical streamflow statistics at ungaged sites where no data are measurements), basin characteristics and estimated available, and to provide a better understanding of the streamflow statistics are provided in this report for physical mechanisms that cause streamflow to vary in each of the LFPR stations. Location information, time and space. streamflow-gaging stations for which flows were Regression equations were developed for each correlated to those at the LFPR station, years of Basin Yield study. Initially, data for only a small operation, and remarks indicating human influences on number of historical LFPR stations were available for streamflows are also provided for each station.The use along with data for continuous streamflow-gaging estimated streamflow statistics include the 99-, 98-, stations in the regression analyses. As more data for the 97-, 95-, 93-, 90-, 85-, 80-, 75-, 70-, 65-, 60-, 55-, and network LFPR stations were used in the regression 50-percent duration flows; the 7-day, 10- and 2-year analyses, the validity and applicability of the equations low flows; and the August median flow. Basin for estimating streamflow statistics for ungaged characteristics measured include drainage area; total stream length; mean basin slope; area of surficial streams increased. stratified drift; area of wetlands; area of water bodies; The first Basin Yield study (Ries, 1994a) and mean, maximum, and minimum basin elevation. developed regression equations for estimating the Location information and streamflow statistics also are 99-, 98-, and 95-percent duration discharges provided for 50 continuous streamflow-gaging stations (streamflows exceeded 99, 98, and 95 percent of used for correlation with the LFPR stations. the time). These equations were developed before Streamflow statistics and basin characteristics data from the LFPR network were available. for many stations on Massachusetts streams were Streamflow statistics and basin characteristics for 41 published previously in a series of gazetteers published stations were used in the analysis; of these stations, as Water Resources Investigations Reports, in a series 36 were continuous streamflow-gaging stations and of Hydrologic Atlas reports (see U.S. Geological 5 were historical LFPR stations. Survey, 1987, for a complete listing of both series), in a The second Basin Yield study (Ries, 1994b) series of ground-water assessment reports published as also developed regression equations for estimating Water Resources Investigations Reports (Olimpio and the 99-, 98-, and 95-percent duration discharges. DeLima, 1984; Lapham, 1988; Myette and Simcox, The analyses for these equations included 61 1992; DeLima, 1991; Hanson and Lapham, 1992; stations, 37 continuous streamflow-gaging stations Persky, 1993; Bratton and Parker, 1995; Bent, 1995; and 24 LFPR stations, 19 of which were part of the Friesz, 1996; Klinger, 1996), and in the three previous network established during the first study. Basin Yield study reports by Ries (1994a, 1994b, 2 Streamflow Statistics and Basin Characteristics for Low-Flow Stations in Massachusetts 1997). Many of the stations for which streamflow unconsolidated deposits adjacent to the streams. This statistics are provided in the previous reports are also discharge is termed base flow. High-yielding aquifers included in this report. Where the values are different, usually are in stratified drift, sand and gravel deposits streamflow statistics published in this report supersede along the valley floors of inland river basins and in those published in the previous reports. coastal areas of southeastern Massachusetts. The extent The author would like to thank the MOWR for of coarse-grained stratified drift, as a proportion of its long-term support of this work, especially Peter total basin area, generally decreases from east to west. Phippen for his support and assistance in selecting the The stratified-drift deposits usually are surrounded by stations for the network. The author would also like to upland areas underlain by till with exposed bedrock express his appreciation to the numerous employees of outcrops. Till is an unsorted glacial deposit that the USGS Massachusetts–Rhode Island District who consists of material ranging in size from clay to large assisted with streamflow data collection, analysis, and boulders. Till yields little water to adjacent streams in interpretation; measurements of basin characteristics; comparison to yields from coarse-grained stratified and preparation of this report. In addition, the author drift. As a result, during summertime,