Erosion, Sediment Discharge, and Channel Morpholoy in the Upper Chattahoochee iver Basin, Georgia Erosion, Sediment Discharge, and Channel Morphology in the Upper Chattahoochee River Basin, Georgia With a discussion of the Contribution of Suspended Sediment to Stream Quality By R. E. FAYE, W. P. CAREY, J. K. STAMER, and R. L. KLECKNER GEOLOGICAL SURVEY PROFESSIONAL PAPER 1107 UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1980 UNITED STATES DEPARTMENT OF THE INTERIOR CECIL D. ANDRUS, Secretary GEOLOGICAL SURVEY H. William Menard, Director Library of Congress Cataloging in Publication Data Main entry under title: Erosion, sediment discharge, and channel morphology in the Upper Chattahoochee River Basin, Georgia, with a discussion of the contribution of suspended sediment to stream quality. (Geological Survey professional paper ; 1107) "Open-file report 78-576." Bibliography: p. Supt. of Docs, no.: I 19.16:1107 1. Erosion Chattahoochee River watershed. 2. Sediment transport Chattahoochee River watershed. 3. Chattahoochee River Channel. I. Faye, R. E. II. Series: United States. Geological Survey. Profes­ sional paper ; 1107. QE571.E783 551.3 78-27110 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 Stock Number 024-001-3305-4 CONTENTS Page Page Metric conversion table _______ — ___ V Watershed and channel morphology—Continued Definition of terms ____________ — _ vi Overland flow length ____ —— —— -- ——— -- — -- 26 Abstract ____________ — ______ — __ 1 Erosion and sediment discharge __ ————————————— 28 Introduction ___________ — ____ — ___ 1 Description of environmental factors _____ — ---- 28 Acknowledgments ___ — ________ 1 Land use _______ — _- — - — ----- ———- 28 Description of the problem ____ 1 Soils and topography _____ —— ____-___—_ — 30 Units of measurement _________ 2 Erosion _________-____-_---------------—----- 37 50 Description of study area _________ 2 Sediment discharge ___-__-__--_-------——-— Suspended sediment ___ — - —— — — ___ — 51 Physiography and topography _ 2 Average annual suspended-sediment dis­ Climate _____________________ 4 charge _____---__--____------—-—-- 52 Land use and vegetation ______ 6 Mechanics of suspended-sediment trans­ Dahlonega Plateau ________ 6 port _____-_--_--_------—-—--—— 55 Atlanta Plateau ________ 8 Unmeasured and bed sediment _ — ___ — ____ 58 Geology and soils _____________ 9 Description and source ____ — _ — __-_ — 58 Network description __________ 10 Computation ___________-__--- — — -- — 59 Collection and analysis of water data 10 Transport curves ___________—__—__— 59 Water-data stations ___________ 10 Average annual discharge ___________ — 63 Water-quality data ____________ 11 Delivery ratios ___ — ___________ — __________ — _____ 66 Streamflow data __ ________ 12 Management implications of erosion and sediment dis­ The stream system ________________ 12 charge data ____________------_----—-_---_—-__ 68 Channel characteristics ________ 12 Contribution of suspended sediment to stream quality 72 Flow characteristics ___________ 13 Turbidity _____________________ — — — —— 72 Streamflow hydrographs ___ 13 Chemical quality _____________________ — — — -- 75 Flow durations ___________ 13 Management implications of chemical-quality data __ 80 Watershed and channel morphology 18 Summary _____________-__---_-----_-____------ — - 82 Stream-order analysis _________ 18 Selected references _____________________ — _____ — 84 ILLUSTRATIONS Page FIGURE 1. Map showing area and location of water-data stations ___________ 3 2. Map showing long-term average annual precipitation _____________ 6 3. Map showing long-term average annual air temperature ________ 7 4. Generalized geology of study area _________________________ 9 5. Channel characteristics at: A. Chestatee River near Dahlonega _______ ______________ 14 B. Big Creek near Alpharetta ___________ ____________ 14 C. Chattahoochee River at Atlanta ________ _____________ 14 D. Peachtree Creek at Atlanta _________ ______________ 15 E. Chattahoochee River near Fairburn ______ _____________ 15 6. Graphs showing mean daily streamflow and daily precipitation at: A. Chestatee River near Dahlonega _______ ______________ 16 B. Big Creek near Alpharetta _________________________ 16 C. Chattahoochee River at Atlanta _______ ____________ 17 D. Peachtree Creek at Atlanta _________ _________. 17 7. Flow duration curves at: A. Chestatee River near Dahlonega _______________________ 20 B. Big Creek near Alpharetta __________________________ 20 C. Chattahoochee River at Atlanta ______________________ 21 D. Peachtree Creek at Atlanta _________ ______________ 21 in IV CONTENTS Page 8-15. Graphs showing: 8. Relation of number of channels to stream order _________ — -___ ——— _ — — — ———— 23 9. Relation of average drainage area to stream order _______ — ___ —— _____ —— —— — — 23 10. Relation of average channel length to stream order ____ ———— - ———— ——————————— - 23 11. Relation of cumulative average channel length to stream order ——————_—————————— 23 12. Relation of average channel drop to stream order _________ —— ———— ____———————— 23 13. Relation of cumulative average channel drop to stream order —————————————————— 24 14. Relation of average channel slope to stream order ————————————————————————— 24 15. Relation of average drainage area to cumulative average channel length ——— ——— —— __ 25 16. Relation of cumulative average channel length to true stream order —___ — — _ — ___ — ______ 26 17. Relation of number of channels to true stream order_____ — __________________ — _________________ 27 18-23. Maps showing land use in watersheds draining to: 18. Chattahoochee River near Leaf ___ —— _________ — —— — ________ — ___________ — _— 31 19. Soque River near Clarkesville _________ — ______________ — ____ —— __ — _-_ ———— — 32 20. Chestatee River near Dahlonega ___- ——— ____________________ —— — __ — ______ — —— 33 21. Big Creek near Alpharetta _______ — ____——________________________---------_ — _____ 34 22. Peachtree Creek at Atlanta, Nancy Creek at Atlanta, and Woodall Creek at Atlanta —— 35 23. Snake Creek near Whitesburg ______——_____________-____---_-_-_- — _ —— —— — - 36 24. Photographs showing typical basin land uses ____ — _______-_____--___---_-__-_-_--- 37,38,39,40,41,42 25-30. Maps showing soil associations in watersheds draining to: 25. Chattahoochee River near Leaf ___________—-__-____-_ — _____________________________ 43 26. Soque River near Clarkesville ____ — _______--_-----_----__----__ — ____ — ______ — _____ 44 27. Chestatee River near Dahlonega _______—-- — ----- ————— _____________ ————— ____ 45 28. Big Creek near Alpharetta _______———————— ————— -- —— --———————————— 46 29. Peachtree Creek at Atlanta, Nancy Creek at Atlanta, and Woodall Creek at Atlanta —— 47 30. Snake Creek near Whitesburg ____________---------- — -------- — ______________ —— _ 48 31-35. Graphs showing relation of suspended-sediment concentrations to stream discharge at: 31. Chestatee River near Dahlonega _______— — __________________ ——— _ — _________—— 51 32. Big Creek near Alpharetta _____________ — _---------------_-------------_---_-_ — _ — _ 52 33. Chattahoochee River at Atlanta ___________----------- — ------_- — _--___-_____———— 53 34. Peachtree Creek at Atlanta ___________--_- — -------------_-----------------___ — _____ 54 35. Chattahoochee River near Whitesburg ___—------______ — ______________ — _____________ 54 3/6-40. Graphs showing lateral distributions of suspended-sediment concentration, flow velocity, flow depth, and size of bed material at: 36. Chestatee River near Dahlonega __-___-__-------------- — ___--___-__-________ — _—— 56 37. Big Creek near Alpharetta _________———___-_-____ — ___ — _ —— _______ — — ___— 57 38. North Fork of Peachtree Creek near Atlanta ————————— ————————— __ ———— ————— 58 39. Peachtree Creek at Atlanta _______--——————————————————————————————— 60,61 40. Snake Creek near Whitesburg ___________-- — ------__--_--________-_________________ 62 41. Graphs showing storm loading of suspended sediment at: A. Chestatee River near Dahlonega ____________----_-------_ — - — _______________ — _______ 64 B. Big Creek near Alpharetta __________________ — --____-______ — _____________ — _______— 64 C. Snake Creek near Whitesburg _____________-- — -__-______ — _____________ — _ — _ — _ — ___ 65 D. Chattahoochee River near Whitesburg ____ — -- — _____________ — _______ — _ — _ — ____ — _— 65 42. Photographs of typical streambeds and stream channels on the Dahlonega and Atlanta Plateaus _______________________________„_ — — — — — __ — — — — __ — _ — — 66,67,68,69 43. Graphs showing relation of unmeasured- and bed-sediment discharge to stream discharge at: A. Chattahoochee River near Leaf __________ — _-_-----_-______________________ — _ — _ — ___ 70 B. Chestatee River near Dahlonega ____________ — _______________ ———— ___________ — ___ 70 C. Big Creek near Alpharetta ________________------------_-- — _____________ — ____ — ____— 71 D. Chattahoochee River at Atlanta _______ — - —— -- — ------ —— _ —— — _________ — ___ 71 E. Peachtree Creek at Atlanta _________-- ———————— — —————— — --- ———— ———— 71 F. Chattahoochee River near Whitesburg _____-- — --_____ — ____________________________— 71 44. Graphs showing relation of turbidity to suspended silt plus clay concentrations at: A. Chestatee River near Dahlonega ___________--- — -_-__-____ — _____________ — ____________ 73 B. Big Creek near Alpharetta _______________-- — — -- — — ________________ — __ — — 73 C. Chattahoochee River at Atlanta ___________-_------_-__-_—_____________