TREATING RIVERS RIGHT & EXAMPLES OF BEST USE OF WOOD IN RESTORATION James Mac Cartney, TU River Restoration Specialist John Braico, MD, NY Council Resource Mgr Grassroots Trustee 1
Great Trout Streams are no accident! Natural Streams and Rivers are: - self sustaining carpenters of their own edifices & - creators of all aquatic habitat 2
Natural Steams key concepts Unimpeded natural processes generate stable stream patterns or types (A-G,1-6)according to the laws of physics while interacting with the landscape Consequence: complex physical systems formed are perfectly suited to all the life found there (i.e, they evolved to fit!) 3
Common Types of Trout Streams (grossly simplified!) Hi Gradient (4-10%): torrents (A) Medium Gradient (2-4%) (B) step pools, riffle/run dominant (B) (2-4%), G (gullies), D Low-Medium gradient(< 2%): classic riffle/pool (C), ( F ), braided (D) Low gradient (<< 2%): highly meandering (spring creeks, meadow) (E) (protect) 4
What s a good trout stream? Stable Form: low W/D, stable banks, short steep riffles & deep runs, deep flat pools (or step pools), gravelly glides, BHR = 1 (all essential features) Ample Habitat ( abundant LWD & larger rocks bank/bed) => Roughness (& is not embedded with sand) For fish of all stages & sizes For insect life -- For flow diversity/scour/deposition Good riparian zone (>1 Wbkfl, 2-3x ) rooted banks, canopy, energy inputs from leaves, source of LWD recruitment, easily accessed flood plain for sediment deposition, energy control, flood attenuation, ground water Healthy Water: Cold clean consistent flows, + chemistry 5
Healthy Mountain Stream great trout water note: roughness, riparian zone 6
Starting Upstream (mod gradient B ) riffle run pool glide 7
Stable Streams have: Intact watersheds, full access to fxnl floodplain & consistent flow patterns Hardly change at all when monitored over many decades Even when subjected to massive flows Changes in width is measured in fractions of inches/ major flood event! (Not in feet or yards!) 8
Stable reference E. Br. Ausable (glide, riffle, run) 6 days post Irene 9
E. Br. Ausable (Irene + 6) 10
Restoration is NOT: Patching an ailing stream system Plugging in a device to meet a local fisheries objective or just shoring up a failing bank, NOT: Just improving the fishing Just stabilizing banks Just reducing flood impacts Just creating pools NB: Streams are unforgiving only fools rush in! 11
Instead: Restoration Aims to Return a disturbed stream system (reach level) to healthy functioning condition modeled after nature & natural stream processes: With Stable channel size & form W, D, A, meander pattern, profile, roughness/substrate With good connection to a fxnl floodplain With a healthy riparian zone (50 min or more) With overall -- Healthy biologic, geomorphic, hydraulic & water quality functional status 12
Stream Restoration an evolution from Keyholes to Systems Biologists adult habitat fixes (1930-70 s) Classic habitat devices ( 50/50 at best) Engrs move water from pt A->pt B (1800 --1990 s) Trapezoidal channels to contain & transport water Geomorphologists: maintain stability while moving sediments (1980 s early 2000 s) Rosgen & others Functional Integrated Systems ( 05 now): Meet all functions: Form, Processes & Biologic needs 13
2012 Functional Restoration EPA underpinning by lower levels + dynamic interplay between: Level 5 Biologic Fxns (fish,bugs,micro) Level 4 Physio-Chemical Fxns (WQ) Level 3 Geomorphic (transport Sed & LWD) Level 2 Hydraulic Fxns (water in channel) Level 1 Hydrologic Fxns (water to channel) underpinned by: Climate, Geology & land use 14
So Restoration Requires: Finding out what s going on? Accurate Analysis Accurate Diagnosis Simple screening more complex What is driving it? Why? Where it s heading? worsening, shifting, or recovery Answers give best options to recover stability help fishery (including limiting factor analysis) 15
Streams provide optimal habitat All life stages of fish: egg, alevin, fry, YOY, adult Riffle, run, pool, glide, backwater, shallows, LWD All life stages of invertebrates: insect, crustacea (egg, larval, nymphal, adult) Riffle, run, pool, glide, backwater, shallows, LWD, detritus, leafy inputs For best outcomes, include everything 16
Key objectives in geomorphic restoration Right size (W, D, W/D, Area) Full connection to floodplain (low bank at or near floodplain/bkfl elevation) Min FPr width: B = 2x W C = 4x W E= 20x W Right slopes: riffles, runs, pools, glides Able to transport all bedload (input = output) Good hyporrhehic zone, not embedded Good bed & bank roughness Riparian buffer: ideally 6x Wbkfl (not less 50 ) 17
Modeling after nature: reference reach Match valley & stream types Use measured ratios related to bankfull width from the reference reach applied to the disturbed stream Ensure that restored channel handles bankfull flows & bedload in = bedload out Use native materials 18
Use of wood in restoration/habitat Roughening banks & riparian zone Sediment deposition & Scour Flow deflection (Log Vanes) Disrupt helical flows (Log Jams, Toe Wood) Habitat fish & bugs Toe Wood, Log Jams Narrowing over- wide channels (Toe Wood, Root wads, Log vanes) 19
Log Vanes Designed to roll energy away from bank & so stop erosion (typical use on bends) 20-30 degree angle to bank, extending 1/3 of channel width, pointing upstream & sloping 6-8 deg from bankfull to thalweg Cheap, local materials, simple to install, durable Construction sequence 20
1 st bend: lay out 3 log vanes to deflect energy from bank, deepen + habitat 21
Trench in logs @ 4-6% grade & 25 degr 22
Tack on filter fabric to anchored vane 23
Tips & butts anchored & braced 24
Add river cobble to fill in ramp face 25
3 completed vanes: check current shifts, where would trout lie? 26
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Root Wads 15 log with 10 root fan & DBH 12-18 set in deep trench on footer log, with root fan perpendicular to flow, anchored & buried so much of root fan is submerged all flows No longer recommended for bank stabilization Best current uses: To roughen margins (2007 USFS) To narrow channel (2008 USFWS) As part of Toe Wood Structure (2008 Rosgen) 29
Battenkill VT: dimension, pattern, profile, riparian zone all OK. Deficit: boundary roughness Solution: anchored LWD 5X Trout population 30
Anchored Rootwad Battenkill VT 31
Rootwads to narrow a low flow channel & improve sinuosity Use alternate sides at 45 deg angle pointing upstream Half entrench log & root fan into bed extending back to ~.5 bankfull at bank Brace & anchor with boulders Problems none to date Yield very good to excellent (Irene tested!) Cheap! 32
Adding root wads for habitat & improving w/d ratio in over wide habitat poor reach (rock anchors) 33
Just upstream 43 rootwads added to alternate sides (trout # 3X or more) 34
Toe Wood Structure Remarkably effective on eroding bends Great instant habitat trout, bugs, all fish Low cost ~ $40 - $50/ LF if free local materials Very durable (even to large flood events) Placed low, kept wet, good access to a bankfull bench to reduce local flood energy on bank Looks natural Caveats follow specs, lots of ballast, revegetate, consider log vanes at both ends 35
Bends 1 & 4: adding 1140 of Toe Wood Structure in front of bank 36
Logs laid out @ 10 on center with footers, braces & rock ballast 37
Next: skidder hauls in tree tops 38
Then hay or coir mat laid on tree tops/brush _I_ to bank, then gravel or soil 39
Then live willow poles, coir mat, more soil 40
2nd TWS: Roughness, narrowing => bank resiliency, Habitat, sediment transport, reconnect to flood plain 41
2 nd & 3 rd Toe Wood Structures 42
2 weeks post 2 nd flood 1140 intact 43
2 nd TWS post 10 floods 44