Studies of longitudinal stream profiles in Virginia and Maryland

Abstract

Relation of particle size of material on the bed to stream IntroductionL 47 length L Methods of study and definitions of factors measuredL 47 Mathematical expression of the longitudinal profile and Description of areas studied L 49 its relation to particle size of material on the bedL Middle River basinL 50 Mathematical expression in previous work on longitudinal North River basinL 50 profiles L Alluvial terrace areasL 50 Origin and composition of stream-bed materialL Calfpasture River basinL 50 Franks Mill reach of the Middle River L Tye River basin L 52 Eidson CreekL Gillis Falls L 52 East Dry Branch L Coastal Plain streamsL 53 North RiverL Factors determining the slope of the stream channelL 53 Calfpasture ValleyL Discharge and drainage areaL 54 Gillis FallsL Size of material on the stream bedL 54 Ephemeral streams in areas of residuumL Channel cross sectionL 61 Some factors controlling variations in size: conclusions_ _ _ Summary of factors controlling channel slopeL 61 The longitudinal profile and the cycle of erosionL Factors determining the position of the channel in space: the References cited L shape of the long profileL 63 IndexL Relation of stream length to drainage area L 63 ILLUSTRATIONS Pag e 54 34.Comparison of computed profiles with actual 16.Relation between drainage area and slope at all profilesL localitiesL 55 35.Map of Middle River near Franks Mill showing 17.Plan of short reach of Middle River above Franks changes in relative amounts of different types Mill L 56 of rock in the stream bedL 18. Relation between slope and median size of bed 36.Median particle sizes of lithologic components of materialL 57 bed material in Middle River near Franks Mill 19.Relation between slope and the ratio of particle 37. Rate of decrease in size of sandstone component size to drainage area L 58 with distance of travel L 20. Relation of slope to particle size for streams in 38.Relations between distance of travel of three two groups having different drainage areas__ _ _ 59 lithologic components and percent of the 21.Three-component diagram showing general relacomponent in the bed loadL tions between slope, drainage area, and size, 39.Sketch map of Middle River at bed below Franks based on equation 2L 60 MillL 22. Relation of drainage area to width and depth_ _ 61 40.Size and composition of bed material at locality 23.Relation of drainage area to depth-width ratio_ __ 62 592 showing lateral changesL UT IV ILLUSTRATIONS (Continued) '14 Page Page 41.Relation of size of bed material to amount of 45.Relation of slope to length typical of seven areas limestone presentL 80 of different geology L 88 42.Sketch map and profile of lower Eidson Creek _ _ _ 81 46.Longitudinal profiles typical of four areasL 88 43.Longitudinal profile of East Dry Branch, and 47.Longitudinal profile of East Dry Branch and relation of reddish sandstone pebbles and boul-Middle River L 89 ders to reddish sandstone outcropsL 83 44.Relation of channel slope to length of streams in areas of contrasting lithologyL 87 TABLES Page PageTABLE 1. Measurements at locality 654, Calfpasture River, stone in the accumulation downstream from the to show variations in size of bed material in a cliff of figure 38L 79 short reach L 55 5. Grid analyses of material on a talus slope on the 2. Values of the constants j and m for four streams_ _ _ 73 east side of the Calfpasture River valley, locality 3. Comparison of profile equations computed from 625L 84 data on size of material on the bed, with profile 6. Median size and amount (percent) of lithologic equations computed from actual elevations in components of bed material at localities on the streamsL 73 Gillis Falls, Md.L 85 4. Parameters obtained by grid analyses, showing 7. Particle-size and slope data in short streams whose size and amount of boulders of tufa and lime-channels contain fine-grained soil materialL 86 8. Principal measurements at selected localitiesL 91