Stream Restoration Using Natural Logs and Sculpted Concrete Logs ...
Stream Restoration Using Natural Logs and Sculpted Concrete Logs ...
Stream Restoration Using Natural Logs and Sculpted Concrete Logs ...
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CASFM 2013<strong>Stream</strong> <strong>Restoration</strong> <strong>Using</strong> <strong>Natural</strong> <strong>Logs</strong> <strong>and</strong><strong>Sculpted</strong> <strong>Concrete</strong> <strong>Logs</strong> to Mimic <strong>Natural</strong>Drop StructuresPresented By:Dave Skuodas, UDFCDKyle Hamilton, CH2M HILL
Concept Development• Vision for the Project: Mimic NatureFrying Pan River
Guanella Pass
Clear Creek
Site Selection• Timbers Creek– Douglas County, CO– Ephemeral stream– Conifer forest– S<strong>and</strong>• Rock Creek– Superior, CO– Perennial stream– Many fallen cottonwood trees– Gravel / cobble
Design• Channel slope• Hydraulic capacity• Aesthetics• Geometry– Single logs– Stacked logs– Sloping face• Buoyancy• Constructability• Longevity• Upstream <strong>and</strong>downstream dropsincorporate sheet pilecutoffs
Log Parameters• Wood Type <strong>and</strong> DecayResistance– Cedar: longevity– Pine: readily available– Cottonwood: verycommon along localstreams• Available lengths <strong>and</strong> diameters• Density differences• Bark for aesthetics• Milled logs allow for tighterspecificationsCedarPineCottonwood
Buoyancy Resistance• <strong>Natural</strong> log structures are notanchored, but are interlocked <strong>and</strong>have root structure• Urban setting dem<strong>and</strong>s structuralintegrity - tax payer dollars beingused• Pilot project included anchoringsystem analysis– Soil <strong>and</strong>/or boulder cover– Cable <strong>and</strong> duck bill anchors– <strong>Concrete</strong> anchors• Conservative approach selectedfor these projects (concreteanchors)
Rock Creek Channel ImprovementsPROJECTLOCATIONProject LimitsFlatirons MallFlowProjectLimits
ConstructionCedarPineFallen Cottonwood
Faux (<strong>Concrete</strong>) Log Concept Development• Mimic natural fallen logs• Use log arrangement as flowsplitter for main-channel <strong>and</strong>overbank storm flows• Sheet pile cutoff wall• Shotcrete, sculpting, <strong>and</strong> stainingfor aesthetics
Faux Log Flow Splitter
<strong>Concrete</strong>
<strong>Concrete</strong>
Observations• Log diameters will vary alonga long log length, trimmingmay be required• Cable <strong>and</strong> duck bill anchorsare a likely alternative to theconservative concrete blockanchor system• Undermining potential canbe addressed through cutoffsystems (sheet pile,geotextile, clay)
Cedar
Cedar
Cedar
Cutoffs
Cedar
Cottonwood
Cottonwood
Cottonwood
Cottonwood
Cottonwood
Cottonwood
Cottonwood
Monitoring• Monitoring Goals– Log longevity <strong>and</strong> decay rate– Structural stability– Differing abrasive forces froms<strong>and</strong>y soils versus gravel /cobble soils• Log drops are not an approvedUDFCD drop structure methodat this time• Definition of Success?
Conclusions<strong>Logs</strong> – Not necessarily cheap or local, but niceoption; straighter the better.Log longevity – So far so good, but submergedis better.<strong>Sculpted</strong> logs – look nice, but cost must bejustified.
Acknowledgements• Timbers Creek Project– Project Lead: UDFCD– Partnering Agency: Douglas County, Colorado– Design Engineer: CH2M HILL, Denver, Colorado– Contractor: Naranjo Civil Constructors, Greeley, Colorado• Rock Creek Project– Project Lead: UDFCD– Partnering Agency: Town of Superior, Colorado– Design Engineer: CH2M HILL, Denver, Colorado– Contractor: L&M Enterprises, Inc., Denver, Colorado
Thank YouQuestions?Dave Skuodas, UDFCD: DSkuodas@udfcd.orgKyle Hamilton, CH2M HILL: Kyle.Hamilton@ch2m.com
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