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RANDOM BOULDER FIELDS {RBF} (For bank protection) 2 EXAMPLES

RANDOM BOULDER FIELDS {RBF} (For bank protection) 2 EXAMPLES.

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RANDOM BOULDER FIELDS {RBF} (For bank protection) 2 EXAMPLES

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  1. RANDOM BOULDER FIELDS {RBF} (For bank protection)2 EXAMPLES

  2. Typically a Random Native Boulder Field is built in-channel adjacent to the bank of concern to strengthen that area, increase hydraulic roughness, increase turbulence, partially block flow, decrease flow velocities, dissipate energy, & shift velocities & the thalweg toward the center of the stream. RBF increase habitat diversity, & can increase aeration & dissolved oxygen. Aesthetics can be anywhere from natural appearing to soothing & stupendous!!

  3. Taking the classic concept of making the bank of concern hydraulically rougher & tougher, & the opposite bank smoother & weaker, the RBF also increases the bed roughness near the bank of concern!!!

  4. POPLAR RIVER, LUTSEN, MN. SEPARATING THE MEGA-SLIDE FROM THE RIVER (AND MORE) By the stream dream team

  5. Stream stabilization/restoration:Conceptually we will separate the stream from the 90+ ft tall hill, & in the channel we will make the inside of the bend smoother & the outer section of the bend & bank hydraulically rougher & tougher.

  6. PRE-PROJECT PHOTOSby Dave DerrickAUGUST 13, 2007(Lowest flow in almost 30 years)

  7. From top of mega slump looking US. In some sections the outer section of the channel was smooth & inner section boulder strewn, that will be reversed!!! Derrick-8-13-2007-lowest flow in 30 yrs

  8. THE PLAN

  9. Stream Project Functions: Bendway Weirs move scour & the thalweg away from attacked bank, with velocities reduced within weir field & on bank. Randomly placed native boulder field increases roughness, increases turbulence & complexity, & decreases flow velocities. Vegetation roughness reduces near-bank flow velocities. Roots strengthen bank & bind soil. Mini-swale captures colluvium.

  10. Not shown on the next slide, but a Random Boulder Field (RBF) will be installed within the Bendway Weir field.

  11. Mega Slump Mega- Slump Stream Project Planform Keys Boulder Revetment Bendway Weir Pre-dug Scour Holes Mini Swale Bridge Transplanted Veg

  12. A couple pebbles to be used for the keys & Bendway Weirs. Boulder specifications: D-100: max 54 inches, min 40 inches; D-50: max 38 inches, min 32 inches; D-35: max. 28 inches, min 22 inches. CONSTRUCTION-POPLAR RIVER @ MEGA-SLUMP-PIX BY DERRICK 8/5-8/2008

  13. CONSTRUCTION PHOTOSby Dave Derrick and Jay MichelsAUGUST 5-8, 2008

  14. Looking DS @ constructed mini-weir & Bendway Weir #1. Note constructed boulder field & pool riffle-pool complex on right side of channel CONSTRUCTION-POPLAR RIVER @ MEGA-SLUMP-PIX BY DERRICK 8/5-8/2008

  15. CONSTRUCTION PIX OF RANDOM SCATTERING OF BOULDERS TO CREATE THE BOULDER FIELDS BETWEEN THE BENDWAY WEIRS

  16. Looking DS @ boulder flying though air CONSTRUCTION-POPLAR RIVER @ MEGA-SLUMP-PIX BY DERRICK 8/5-8/2008

  17. Looking DS @ the big boulder splash CONSTRUCTION-POPLAR RIVER @ MEGA-SLUMP-PIX BY DERRICK 8/5-8/2008

  18. Looking DS @ 2 more boulders flying though air CONSTRUCTION-POPLAR RIVER @ MEGA-SLUMP-PIX BY DERRICK 8/5-8/2008

  19. Looking US @ completed boulder field & Bendway Weir & stone toe & Jay. Does it look natural???? I would say so… Smooth on inside of bend CONSTRUCTION-POPLAR RIVER @ MEGA-SLUMP-PIX BY DERRICK 8/5-8/2008

  20. Stream Project Functions:::::::: • Longitudinal toe stone provides scour protection • Toe stone protection completely separates stream from Mega Slump • Willow poles provide vegetative roughness, increase height of “soft protection”, shades stone & water, & has many wildlife functions {everything from carbon input to structure cover to insect production, beneficial to pollinators, etc.} • Mini-Swale provides a storage area for colluvium from Mega Slump • Bendway Weirs increase stream roughness, reduce toe scour, provide diversity & complexity of depth, velocity (horizontal & vertical) & substrate, plus they move the thalweg away from the toe of the eroding bank. • The dug pools at the ends of the Bendway Weirs provide mini pool-riffle-pool sequences throughout the bend. • Boulder fields provide additional roughness, plus a “natural” look

  21. CONSTRUCTION COMPLETE (going from upstream to downstream) Photos by Dave Derrick AUGUST 8, 2008

  22. Looking DS. Boulder field to left, dug pools & riffles on right CONSTRUCTION COMPLETE-POPLAR R. @ MEGA-SLUMP-PIX BY DERRICK 8-8-2008

  23. Looking DS @ constructed mini-weir & Bendway Weir #1. Note constructed boulder field & pool riffle-pool complex on right side of channel CONSTRUCTION-POPLAR RIVER @ MEGA-SLUMP-PIX BY DERRICK 8/5-8/2008

  24. Looking DS @ toe stone & Bendway Weirs 2 - 4. BW#4 BW#3 BW#2 CONSTRUCTION COMPLETE-POPLAR R. @ MEGA-SLUMP-PIX BY DERRICK 8-8-2008

  25. Looking DS @ Bendway Weirs # 4 & 5. Diversity & complexity of flow CONSTRUCTION COMPLETE-POPLAR R. @ MEGA-SLUMP-PIX BY DERRICK 8-8-2008

  26. Looking at constructed natural appearing random boulder field (foreground) & random chaotic stone toe CONSTRUCTION COMPLETE-POPLAR R. @ MEGA-SLUMP-PIX BY DERRICK 8-8-2008

  27. Looking US @ pool & colorful boulder assemblage. CONSTRUCTION COMPLETE-POPLAR R. @ MEGA-SLUMP-PIX BY DERRICK 8-8-2008

  28. Watching the river flow, looking US @ Bendway Weir #5 & boulder field CONSTRUCTION COMPLETE-POPLAR R. @ MEGA-SLUMP-PIX BY DERRICK 8-8-2008

  29. Watching the river flow, looking US @ BW #5 & boulder field, fantastic diversity of depth, velocity, turbulence, substrate, holding water (refugia) CONSTRUCTION COMPLETE-POPLAR R. @ MEGA-SLUMP-PIX BY DERRICK 8-8-2008

  30. Looking US @ placed boulders dissipating stream energy CONSTRUCTION COMPLETE-POPLAR R. @ MEGA-SLUMP-PIX BY DERRICK 8-8-2008

  31. Looking DS @ stone toe, boulder field, & Bendway Weirs 7 & 8. CONSTRUCTION COMPLETE-POPLAR R. @ MEGA-SLUMP-PIX BY DERRICK 8-8-2008

  32. Looking US @ Bendway Weir #7 & stone toe, smooth on inside of bend, rough on outside of bend. CONSTRUCTION COMPLETE-POPLAR R. @ MEGA-SLUMP-PIX BY DERRICK 8-8-2008

  33. Looking DS @ Key #8 (with veg) & BW #8. Note pools & flow at end of weir CONSTRUCTION COMPLETE-POPLAR R. @ MEGA-SLUMP-PIX BY DERRICK 8-8-2008

  34. Looking DS @ stone toe, boulder field, & Bendway Weirs 7 & 8. CONSTRUCTION COMPLETE-POPLAR R. @ MEGA-SLUMP-PIX BY DERRICK 8-8-2008

  35. SITE 4: MINIMAL BANK STABILIZATION TO REDUCE THE SEDIMENT LOAD INTO DINGMANS CREEK FROM THE SMALL SLIDEDELAWARE WATER GAP NATIONAL RECREATION AREA, NATIONAL PARK SERVICE PROJECT CONSTRUCTED SEPTEMBER 24, 2009

  36. PROBLEMS • For approximately 200 ft Dingmans Creek is flowing against & eroding the left valley wall (estimated height 35 ft). The amount of fine sediment delivered to the stream is significant. This entire colluvium slide is very unstable. If erosion progresses at this site it may kick the stream back toward the park road downstream and create a threat to road stability (Johnny B. Mountain Road). • The point bar (right side) of the channel is very rough with a number of boulders increasing the hydraulic roughness & impeding flow.

  37. METHODS EMPLOYED • 35 Vegetated Traffic Control Stones (TCS) • Every 4th TCS is keyed 10 ft into the bank (perpendicular) with rooted Black Willow whips & other live poles planted at a rate of 3 plants per ft. • Every 4th TCS has a Single Stone Bendway Weir (SSBW) to move the thalweg away from the left bank & toward the center of the channel approximately 5-8 ft. • The space between & behind the TCS is heavily vegetated with a variety of species of rooted-stock trees & shrubs. • The loose eroding talus slope slide was heavily planted with several species of rooted-stock shrubs & trees • Native boulders from the point bar were placed as a random boulder field streamward of the TCS & SSBW.

  38. PRE-PROJECT PHOTOSby Dave Derrick(HIGH WATER)

  39. HIGH WATER-Looking DS @ fast water (smoother bed) near bank. PRE-PROJECT DINGMANS CR-SITE 4 PIX BY DERRICK 7-24-2008

  40. HIGH WATER-Looking DS @ smoother bed near bank, rougher toward inside of bend!! PRE-PROJECT DINGMANS CR-SITE 4 PIX BY DERRICK 7-24-2008

  41. HIGH WATER-Looking US @ project bank. Erosion of bank is contributing significant sediment to the system. Bed is rough on the inside of the bend, but smooth near eroding bank PRE-PROJECT DINGMANS CR-SITE 4 PIX BY DERRICK 12-15-2008

  42. HIGH WATER-Looking DS toward DS end of project, smoother bed near bank, rougher toward inside of bend!! PRE-PROJECT DINGMANS CR-SITE 4 PIX BY DERRICK 12-15-2008

  43. SOLUTIONS (THE PLAN) • This project is designed to stabilize 200 ft of the bank at the present location by increasing roughness of the entire bank with 3 gallon container rooted-stock trees & shrubs. • Hard protection is limited to the toe & includes 35 vegetated Traffic Control Stones (TCS). TCS were typically 3 ft by 3 ft by 4 ft & spaced 3 to 6 ft apart. Every 4th TCS was keyed 8 to 10’ into the bank & had a Single-Stone Bendway Weir (SSBW) placed at the stream end. Live poles were placed in the key trench before stone was placed. Eight SSBW were built. • A random natural bedload boulder field was placed around & in front of the SSBW & TCS’s.

  44. Courtesy of Ecological Restoration, Inc

  45. Correction: There should be 3 Traffic Control Stones between each Single Stone Bendway Weir, not 2. Courtesy of Ecological Restoration, Inc.

  46. TCS SSBW Key Courtesy of Ecological Restoration, Inc.

  47. Two healthy Single Stone Bendway Weir (SSBW) stones. CONSTRUCTION DINGMANS CR-SITE 4 PIX BY DERRICK 9-19-2009

  48. PLANTS PLANTED Common Name # Size • Gray Birch 50 2 gallon pots • Gray Birch 200 unrooted poles • Buttonbush 25 bare root • Silky Dogwood 200 bare root • Ninebark 175 bare root • Rhododendron 50 3 gallon pots • White Pine 150 3 gallon pots

  49. Key Traffic Control Stones (TCS) with Single Stone Bendway Weirs (SSBW) & vegged keys & pole plantings Key Key Key TCS TCS TCS Key TCS TCS Key SSBW TCS TCS TCS SSBW Key Thalweg TCS SSBW Traffic Control Stones (TCS) sized about 3 ft by 3 ft by 4 ft, dug into the bed & bank, designed to stabilize & roughen the bank, are spaced 3 to 6 ft apart. Every 4th TCS is keyed into the bank & has a Single Stone Bendway Weir attached. 8 SSBW total

  50. Scoop a hole into the bed & bank for the Traffic Control Stone (TCS), then place live poles against bank, push the TCS into position, then backfill. TCS were typically 3 ft by 3 ft by 4 ft & spaced 3 to 6 ft apart. Every 4th TCS was keyed 8 to 10’ into the bank & had a Single-Stone Bendway Weir (SSBW) placed at the stream end. Live poles were placed in the key trench before stone was placed. A random natural bedload boulder field was placed around & in front of the SSBW & TCS’s. All bare areas of the slide area were planted with 3 gallon container rooted-stock trees & shrubs.

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