Rc101 Day 1 Jennings 10

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Rc101 Day 1 Jennings 10

  1. 1. Stream Morphology Assessment<br />Greg Jennings, PhD, PE<br />Professor, Biological & Agricultural Engineering<br />North Carolina State University<br />jennings@ncsu.edu<br />Barbara Doll, PE<br />Jan Patterson, PE<br />Jason Zink, PE<br />Zan Price, PE<br />Kris Bass, PE<br />Justin Church, PE<br />Mike Geenen, EI<br />Mike Shaffer, EI<br />Karen Hall<br />Dave Penrose<br />
  2. 2. Why Restoration?<br /><ul><li>Water quality impairments
  3. 3. Habitat loss
  4. 4. Ecosystem degradation
  5. 5. Land loss
  6. 6. Safety concerns
  7. 7. Infrastructure damage
  8. 8. Flooding
  9. 9. Aesthetics</li></li></ul><li>Stream Insults<br /><ul><li>Straightening & dredging
  10. 10. Floodplain filling
  11. 11. Watershed manipulation
  12. 12. Sedimentation & stormwater
  13. 13. Pollution discharges
  14. 14. Utilities & culverts
  15. 15. Buffer removal
  16. 16. Disdain & neglect</li></li></ul><li>Stream Impairment Causes (US EPA)<br />Pathogens<br />Sediment<br />Nutrients<br />Habitat Alterations<br />Organic Enrichment<br />Metals<br />PCBs<br />Temperature<br />Flow Alterations<br />Mercury<br />
  17. 17. Restoration Components<br /><ul><li>Channel morphology & floodplain connection
  18. 18. In-stream structures
  19. 19. Streambank bioengineering
  20. 20. Riparian buffers & habitat enhancements
  21. 21. Stream crossings
  22. 22. Stormwater/watershed management
  23. 23. Monitoring & maintenance
  24. 24. Public access & education</li></li></ul><li>Stream Morphology Assessment<br />Fluvial Processes & Forms<br />Streams & Watersheds<br />Stream Ecosystems<br />Stream Morphology<br />Stream Classification<br />Assessment of Condition<br />
  25. 25. Fluvial Processes and Landforms<br />How do stream systems work?<br />What determines stream size & shape (i.e. morphology)?<br />
  26. 26. Fluvial Geomorphology:<br />study of landforms and the fluvial processes that shape them<br />
  27. 27. Fluvial Processes:<br />associated with flowing water, including sediment erosion, transport, and deposition<br />
  28. 28. Hydrologic Cycle<br />Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  29. 29. Fluvial Forms<br /><ul><li>Bar
  30. 30. Channel
  31. 31. Confluence
  32. 32. Cutoff channel
  33. 33. Delta
  34. 34. Floodplain
  35. 35. Gorge
  36. 36. Gully
  37. 37. Meander
  38. 38. Oxbow lake
  39. 39. Pool
  40. 40. Riffle
  41. 41. Stream
  42. 42. Valley
  43. 43. Waterfall
  44. 44. Watershed</li></li></ul><li>What is a Stream?<br />… a body of water with a current, confined within a bed and streambanks<br />Synonyms:  bayou, beck, branch, brook, burn, creek, crick, kill, lick, rill, river, rivulet, run, slough, syke<br />Streams are conduits in the water cycle and also important habitats<br />Photo Credit: Eve Brantley, Auburn University<br />
  45. 45. Watershed<br />
  46. 46. Watershed:<br /> “Area of land that drains water, sediment, and dissolved materials to a common outlet at some point along a stream channel”<br /> Dunne and Leopold, 1978<br />Watershed form is influenced by:<br />Climate<br />Geology & Soils<br />Fluvial Geomorphology<br />Vegetation<br />Land Uses<br />
  47. 47. From Webster's Revised Unabridged Dictionary (1913) :<br />Watershed, n [Cf. G. wasserscheide; wasserwater + scheidea place where two things separate, fr. scheidento separate.]<br />The whole region or extent of country which contributes to the supply of a river or lake.<br />The line of division between two adjacent rivers or lakes with respect to the flow of water by natural channels into them; the natural boundary of a basin.<br />Other Terms: Catchment, Drainage basin, River basin<br />
  48. 48. North Carolina River Basins<br />
  49. 49. Watershed Functions:<br />Transport & Storage:<br />Water<br />Sediment<br />Dissolved Materials<br />Habitat:<br />Animals<br />Plants<br />Humans<br />
  50. 50. Water Transport & Storage<br />Hydrology: The study of the flow of the earth’s waters through the hydrologic cycle<br />Hydrograph: Displays change in flow (discharge over time<br />Peak Flow<br />Rising Limb<br />Falling Limb<br />Mean Daily Flow<br />www.Geology.com <br />
  51. 51. Precipitation<br />Runoff<br />Infiltration<br />Evapotranspiration<br />
  52. 52.
  53. 53. Extreme Weather!<br />
  54. 54. Water Transport to Streams<br />Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  55. 55. Land use in a watershed affects:- water quality- water quantity- ecosystem services<br />
  56. 56. Watershed Stream Network<br />Neuse River Basin, NC<br />
  57. 57. Strahler Stream Order<br />Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  58. 58. USGS Topographic Map – 1:24,000 scale<br />Courtesy of John Dorney and Perianne Russell, NC Division of Water Quality <br />
  59. 59. How to determine stream origins?h2o.enr.state.nc.us/ncwetlands<br />
  60. 60.
  61. 61. Contributing Drainage Areas for Stream Origins(Ephemeral to Intermittent/Perennial)<br />Courtesy of John Dorney and Perianne Russell, NC Division of Water Quality <br />
  62. 62. Problems with Contiguous USGS Maps<br />Headwater stream shown on one map and not the other<br />Tributaries shown on one map and not the other<br />McDaniel Bald and Marble Quadrangles, Cherokee County, NC<br />Courtesy of John Dorney and Perianne Russell, NC Division of Water Quality <br />
  63. 63. Groundwater Influences Streamflow<br />Losing Stream Gaining Stream<br />Groundwater Recharge Groundwater Discharge<br />Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  64. 64. Ephemeral<br />Intermittent<br />Perennial<br />
  65. 65. Stream: A system of fluvial forms & habitats<br /><ul><li>Channel (bed & banks)
  66. 66. Floodplain
  67. 67. Water
  68. 68. Sediment
  69. 69. Plants & animals</li></ul>Photo Credit: Eve Brantley, Auburn University<br />
  70. 70. Streams are ecosystems<br /><ul><li>Communities of organisms and their physical, chemical, and biological environments</li></ul>Courtesy of Francois Birgand, NCSU<br />
  71. 71. Ecosystem Services<br /><ul><li>Provisioning – food, energy, industry
  72. 72. Regulating – climate, waste, nutrients
  73. 73. Supporting – water quality, pest control
  74. 74. Cultural – recreation, inspiration
  75. 75. Preserving – species diversity</li></li></ul><li>Self-Design<br /> The reorganization, substitution and shifting of an ecosystem (dynamics and functional processes) whereby it adapts to the environment superimposed upon it. (Mitsch & Jorgensen, Ecological Engineering)<br />
  76. 76. Fish Biodiversity<br />41<br />185<br />150<br />195<br />41<br />250<br />32<br />236<br />792<br />154<br />
  77. 77. River Continuum Concept<br />Connections<br /><ul><li>Watershed to Corridor to Stream
  78. 78. Biological communities upstream and downstream</li></ul>Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  79. 79. Field Investigations<br />What is living in the stream?<br />What are the physical and chemical conditions of the stream?<br />
  80. 80. Food Web<br />
  81. 81. Stream Ecosystems<br />Mostly downstream fluxes of energy and matter<br />Lateral and vertical connections to the riparian and hyporheic zones<br />Courtesy of Francois Birgand, NCSU<br />
  82. 82. Hyporheic Zone<br />
  83. 83. Stream Functions<br />Transport water<br />Transport sediment<br />Habitat (aquatic & terrestrial)<br />Recreation & aesthetics<br />Safe Water Supply<br />
  84. 84. Stream Corridor Longitudinal Profile<br />Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  85. 85. Sediment Transport<br />Flowing water does work:<br /><ul><li>Erosion
  86. 86. Transportation
  87. 87. Deposition (of alluvium)</li></ul>http://www.uwsp.edu/gEo/faculty/ritter/geog101/textbook/fluvial_systems/geologic_work_of_streams.html <br />
  88. 88. Erosion: Detachment of material from bed and banks<br />95% of stream energy used to overcome friction<br />Remaining energy used for Erosion Processes:<br /><ul><li> Flowing water dissolves materials
  89. 89. Hydraulic action dislodges materials
  90. 90. Abrasion of heavy materials rolling on bottom</li></ul>http://www.uwsp.edu/gEo/faculty/ritter/geog101/textbook/fluvial_systems/geologic_work_of_streams.html <br />
  91. 91. Transportation: Movement of material by water<br />Stream Load includes:<br />dissolved + suspended + bed load<br />Capacity: maximum load that can be transported for a given discharge (increases with velocity and turbulence)<br />Competence: largest size material that can be transported for a given discharge<br />http://www.uwsp.edu/gEo/faculty/ritter/geog101/textbook/fluvial_systems/geologic_work_of_streams.html <br />
  92. 92. Bedload is related to Discharge for Each River<br />
  93. 93. Deposition:<br />Aggradation: Raising the bed elevation<br />Bars: Depositional areas that may change flow directions<br />http://www.uwsp.edu/gEo/faculty/ritter/geog101/textbook/fluvial_systems/geologic_work_of_streams.html <br />
  94. 94. Bed Material (Substrate)<br />Silt/Clay: < 0.062 mm<br />Sand: 0.062 – 2 mm<br />Gravel: 2 – 64 mm<br />Cobble: 64 – 256 mm<br />Boulder: 256 – 2048 mm<br />
  95. 95. Substrate CharacterizationWolman Pebble Count<br />
  96. 96. High Slope Moderate Slope Low Slope<br />Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  97. 97. Sediment Deposition:<br /><ul><li> Point bar
  98. 98. Lateral bar
  99. 99. Mid-channel bar
  100. 100. Transverse bar
  101. 101. Delta bar</li></li></ul><li>Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  102. 102. Point Bars: <br />Inside meander bends<br />
  103. 103. Lateral Bars: <br />Formed in straight channels<br />
  104. 104. Lateral Bars: <br />Formed in straight channels<br />
  105. 105. Mid-channel Bars: <br />Formed in over-wide channels<br />
  106. 106. Transverse Bars: <br />Formed in straight channels<br />
  107. 107. Meandering Stream: Alluvial Forms<br />Flow Downstream<br />Floodplain<br />Scarp<br />Bankfull Stage<br />Point Bar<br />Pool<br />Left Bank<br />Right Bank<br />Riffle<br />Thalweg<br />
  108. 108. Bankfull Stage<br />“corresponds to the discharge at which channel maintenance is the most effective, that is, the discharge at which moving sediment, forming or removing bars, forming or changing bends and meanders, and generally doing work results in the average morphologic characteristics” (Dunne and Leopold,1978)<br />Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  109. 109. Bankfull<br />
  110. 110. Channel Evolution (incision)<br />
  111. 111. Terrace<br />Bankfull<br />
  112. 112. Incised System: Floodplain Creation<br />Terrace<br />Floodplain<br />
  113. 113. Stream Morphology:size and shape of channel & floodplain (dimension, pattern, profile)<br />
  114. 114.
  115. 115. Valley type affects stream morphology<br />Colluvium is loose sediment transported by gravity and deposited at the bottom of a slope.<br />Alluvium is sediment deposited by a river in the channel or floodplain<br />Alluvial valleys occur where sediment particles are dropped by slow-moving water.<br />
  116. 116. Valley Types: (www.epa.gov/watertrain/stream_class)<br />Valley Type II Moderately steep, gentle sloping side slopes often in colluvial valleys<br />From EPA Watershed Academy: Fundamentals of the Rosgen Stream Classification System<br />
  117. 117. Valley Types: (www.epa.gov/watertrain/stream_class)<br />Valley Type VIII Wide, gentle valley slope with well-developed floodplain adjacent to river terraces<br />From EPA Watershed Academy: Fundamentals of the Rosgen Stream Classification System<br />
  118. 118. Stream Corridor Lateral Profile<br />Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  119. 119. Floodplains: Critical Stream Components<br />
  120. 120. Floodplain Functions<br /><ul><li>Floodwater storage
  121. 121. Reducing peak flows
  122. 122. Erosion prevention
  123. 123. Water quality
  124. 124. Groundwater recharge
  125. 125. Food & shade
  126. 126. Habitats</li></li></ul><li>
  127. 127. Terrace<br />Floodplain<br />Left Bank<br />Right Bank<br />Thalweg<br />Streambed<br />Downstream<br />
  128. 128. Terrace<br />Floodplain<br />Right Bank<br />Left Bank<br />Thalweg<br />Streambed<br />Downstream<br />
  129. 129. Pool Cross-Section (Meandering Stream)<br />Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  130. 130. Cross-Section of Channel and Floodplain<br />
  131. 131. Pattern (plan form)<br />Alluvial (low-gradient) streams naturally meander across a valley with a somewhat predictable pattern<br />
  132. 132. Alluvial River Processes<br />http://www.uwsp.edu/gEo/faculty/ritter/geog101/textbook/fluvial_systems/geologic_work_of_streams.html <br />
  133. 133. Sellin and Willetts, Floodplain Processes, Walling, 1996<br />
  134. 134. Oxbow Formation in Meandering Streams<br />Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  135. 135. Chute cutoff across tight meander bend<br />
  136. 136. Oxbows<br />
  137. 137. Oxbows<br />
  138. 138. Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  139. 139. Meandering Stream: Alluvial Forms<br />Riffle<br />Point Bar (deposition)<br />Run<br />Glide<br />Pool<br />
  140. 140. Stream Bedform Variability:Slope Substrate size Velocity OxygenationShear stress Habitats<br />
  141. 141. Profile (bed form)<br />Water Surface<br />Riffle Slope<br />Run Slope<br />Glide Slope<br />Pool Slope<br />Thalweg<br />Pool Spacing<br />
  142. 142. Riffles<br /><ul><li>Steep slope
  143. 143. High velocity
  144. 144. High shear stress
  145. 145. Large substrate
  146. 146. High porosity</li></li></ul><li>Importance of Riffles<br />Areas of oxygenation<br />Highly diverse substrate and habitat<br />Diverse macroinvertebrate population<br />
  147. 147. Pools<br /><ul><li>Flat slope
  148. 148. Low velocity
  149. 149. Low shear stress
  150. 150. Small substrate
  151. 151. Scour during high flow</li></li></ul><li>Importance of Pools<br />Refuge for fish during low flow, drought periods<br />Rest stop and food area for fish<br />Predator refuge for young fish<br />
  152. 152. River Dimensions<br />
  153. 153. Velocities:Low flow and Flood flow<br />Little Garvin Creek, Clemson, SC<br />
  154. 154. Channel dimensions in a meandering stream<br />www.uwsp.edu/gEo/faculty/lemke/geomorphology/lecture_outlines/04_fluvial_landforms.html<br />
  155. 155. Profile is related to Pattern<br />
  156. 156. Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  157. 157. Step Pool Streams<br />(high gradient)<br />Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  158. 158. Grade Controls<br />Nickpoints<br />
  159. 159. Flow diversity improves habitat:<br /><ul><li> Riffles
  160. 160. Steps
  161. 161. Pools</li></li></ul><li>Diversity of habitats<br />
  162. 162. Stream Habitats<br />Macrohabitats: riffles, runs, pools, glides, steps, side channels<br />Microhabitats: roots, leaf packs, wood, rocks, plants, hyporheic zone <br />
  163. 163. What habitats do you see?<br />Pool<br />Leaf Pack<br />Wood<br />Rocks<br />Roots<br />Riffle<br />
  164. 164. What habitats do you see?<br />Roots<br />Wood<br />Pool<br />Leaf Pack<br />Riffle<br />Rocks<br />
  165. 165. What habitats do you see?<br />
  166. 166. Natural Stream Channel Stability<br />(from Leopold)<br />River has a stable dimension, pattern and profile<br />Maintains channel features (riffles, pools, steps)<br />Does not aggrade (fills) or degrade (erodes)<br />
  167. 167. Equilibrium Controlling Variables<br /><ul><li>Width
  168. 168. Depth
  169. 169. Slope
  170. 170. Velocity
  171. 171. Discharge
  172. 172. Flow resistance
  173. 173. Sediment size
  174. 174. Sediment load</li></ul>Leopold et al (1964)<br />
  175. 175. Velocity & Discharge<br />Q = VA = Discharge (cfs)<br />V = Velocity (ft/s)<br />A = Cross-Section Area (ft2)<br />V related to slope, channel shape, and channel roughness<br />Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  176. 176. Manning Formula<br />
  177. 177.
  178. 178. A = 40 sq ft<br />W = 22 ft<br />R = 1.7 ft<br />S = 0.010 ft/ft<br />n = 0.040<br />V = 5.0 ft/s<br />Q = 200 cfs<br />A = 220 sq ft<br />W = 55 ft<br />R = 3.5 ft<br />S = 0.004 ft/ft<br />n = 0.035<br />V = 6.1 ft/s<br />Q = 1350 cfs<br />
  179. 179. Sediment Transport<br />Flowing water does work:<br /><ul><li>Erosion
  180. 180. Transportation
  181. 181. Deposition (of alluvium)</li></ul>http://www.uwsp.edu/gEo/faculty/ritter/geog101/textbook/fluvial_systems/geologic_work_of_streams.html <br />
  182. 182. Velocity & Particle Size Determine Process<br />V = 5 ft/s<br />V = 1 ft/s<br />http://www.uwsp.edu/gEo/faculty/ritter/geog101/textbook/fluvial_systems/geologic_work_of_streams.html <br />
  183. 183. Stream Competence (www.epa.gov/WARSSS)<br />
  184. 184. Shear Stress: fluid force per unit area acting on the streambed <br /> = Rs = Shear Stress (lb/ft2)<br /> = Unit Weight of Water = 62.4 lb/ft3<br />R = Hydraulic Radius (ft) = A / P<br />S = Average Water Surface Slope (ft/ft)<br />A = Riffle Cross-Section Area (ft2)<br />P = Wetted Perimeter (ft) <br />P = Wbkf +2*Dbkf (approx)<br />
  185. 185. A = 40 sq ft<br />W = 22 ft<br />R = 1.7 ft<br />S = 0.010 ft/ft<br /><ul><li> = 1.0 lb/sq ft</li></ul>Competence = ~250 mm<br />A = 220 sq ft<br />W = 55 ft<br />R = 3.5 ft<br />S = 0.004 ft/ft<br /><ul><li> = 0.8 lb/sq ft</li></ul>Competence = ~200 mm<br />
  186. 186. R = 1.5 ft<br />S = 0.0012 ft/ft<br />n = 0.038<br />V = 1.8 ft/s<br />Q = 89 cfs<br /><ul><li> = 0.11 lb/sq ft</li></ul>Competence = ~30 mm <br />
  187. 187. Channel Forming Discharges<br />and Regional Curves<br />
  188. 188. Channel-forming (dominant) discharge<br />Estimated using:<br /><ul><li>Effective discharge
  189. 189. Bankfull discharge
  190. 190. Discharge associated with recurrence interval (typically 1 to 2 year)</li></li></ul><li>Effective Discharge<br />Transports the most sediment over a long time<br />
  191. 191. Bankfull Discharge<br />Flow fills active channel and spreads onto floodplain<br />Represents break between channel & floodplain processes<br />For channel in equilibrium, assumed to equal the effective discharge<br />Return Period typically 1 to 2 years<br />
  192. 192. Bankfull Stage<br />“corresponds to the discharge at which channel maintenance is the most effective, that is, the discharge at which moving sediment, forming or removing bars, forming or changing bends and meanders, and generally doing work results in the average morphologic characteristics” (Dunne and Leopold,1978)<br />Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  193. 193. Bankfull<br />
  194. 194. Bankfull Indicators<br /><ul><li>Top of streambank (floodplain)
  195. 195. Break in slope on streambank
  196. 196. Top of point bar</li></ul>Bankfull<br />Bankfull<br />
  197. 197. Bankfull<br />
  198. 198. Bankfull<br />
  199. 199. Bankfull<br />
  200. 200. Bankfull<br />
  201. 201. Channel Evolution<br />(Succession)<br />Response to incising forces<br />Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  202. 202. Terrace<br />Bankfull<br />
  203. 203. Bankfull<br />
  204. 204.
  205. 205. Bankfull<br />
  206. 206. Bankfull<br />
  207. 207. Taking the Mystery out of Bankfull<br />
  208. 208. Predicting Stream Morphology:<br />Hydraulic Geometry Relationships<br />
  209. 209.
  210. 210.
  211. 211. NC Coastal Plain Regional Curve<br />
  212. 212.
  213. 213.
  214. 214.
  215. 215. Stream Morphology:size and shape of channel & floodplain (dimension, pattern, profile)<br />
  216. 216. Dimension (cross-section)<br /><ul><li>Area
  217. 217. Width
  218. 218. Depth
  219. 219. Width/Depth Ratio
  220. 220. Entrenchment Ratio
  221. 221. Bank Height Ratio</li></li></ul><li>Dimension: Cross-Section<br />
  222. 222. Riffle Dimensions<br />Wbkf<br />Bankfull<br />Abkf<br />dbkf<br />Measure Bankfull Width (Wbkf) and Bankfull Area (Abkf)<br />Mean Depth, dbkf = Abkf / Wbkf<br />Width to Depth Ratio, W/d = Wbkf / dbkf<br />
  223. 223. W/d = 9.3 / 1.5 = 6.2 <br />Wbkf<br />dbkf<br />Abkf<br />
  224. 224. Entrenchment Ratio<br />ER = Wfpa / Wbkf<br />Wfpa = Width of Flood Prone Area measured at the elevation twice bankfull max depth above thalweg<br />Wbkf = Width of Bankfull Channel<br />Wfpa<br />Bankfull<br />2 x dmax<br />above thalweg<br />dmax<br />Wbkf<br />
  225. 225. ER = Wfpa / Wbkf = 75/ 15 = 5.0 <br />Wfpa<br />Wbkf<br />
  226. 226. Rocky Branch Phase II Reach 2:<br />Priority 2 (floodplain excavation, C channel)<br />Entrenchment Ratio = Wfpa / Wbkf = 90/20 = 4.5<br />Wfpa<br />Wbkf<br />Flood water flows onto floodplain several times each year<br />
  227. 227. Rocky Branch Phase II Reach 1:<br />Priority 3 (floodplain excavation, Bc channel)<br />Entrenchment Ratio = Wfpa / Wbkf = 40/20 = 2<br />Wfpa<br />Wbkf<br />
  228. 228. Bank Height Ratio<br />BHR = dmax tob/ dmax<br />dmax tob= Max Depth from top of low bank to thalweg<br />dmax = Max Depth from bankfull stage to thalweg<br />Bankfull<br />dmax tob<br />dmax<br />
  229. 229. BHR = 5.3 / 2.5 = 2.1 <br />Top of Bank<br />Bankfull<br />dmax tob<br />dmax<br />
  230. 230. Pattern: Plan form<br />Alluvial (low-gradient) streams naturally meander across a valley with a somewhat predictable pattern<br />
  231. 231. Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  232. 232. Sinuosity = stream length / valley length<br />K = 1850 / 980 = 1.9 <br />Valley Length<br />
  233. 233. Maximum Sinuosity Decreases with Slope<br />
  234. 234. Plan Form Relationships<br />
  235. 235. Meander Length Ratio = meander length / width = 78/15 = 5.2<br />Meander Width Ratio = belt width / width = 57/15 = 3.8<br />Radius of Curvature Ratio = radius / width = 23/15 = 1.5<br /> Belt Width<br /> Meander Length<br />
  236. 236.
  237. 237. Profile: Bed Form<br />Water Surface<br />Riffle Slope<br />Run Slope<br />Glide Slope<br />Pool Slope<br />Thalweg<br />Pool Spacing<br />Pool Spacing<br />
  238. 238.
  239. 239. Profile is related to Pattern<br />
  240. 240. Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  241. 241. Step Pool Streams<br />(high gradient)<br />Stream Corridor Restoration: Principles, Processes, and Practices. 1998. Federal Interagency Stream Restoration Working Group.<br />
  242. 242. Grade Controls<br />Nickpoints<br />

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