The information in this document has been funded wholly or in part by the United States Environmental Protection Agency.Jennifer R. Weins, Christopher S. Guy & Charles D. Lee, Streambank revetment, Kansas State University, September 1997

Guy, Christopher S.

Lee, Charles D.

Weins, Jennifer R.

K-State Research Exchange

1STREAMBANKREVETMENTKansas State University Agricultural Experiment Stationand Cooperative Extension ServiceKansas State University, Division of BiologyKansas Cooperative Fish and Wildlife Research UnitU.S. Environmental Protection AgencyKansas Department of Wildlife & ParksOutdated Publication, for historical use. CAUTION: Recommendations in this publication may be obsolete.2IntroductionStreambank erosion is a naturally occurringprocess in streams and rivers throughout theUnited States. Accelerated streambank erosionoccurs when natural events or human activitiescause a higher than expected amount of erosion,and is typically a result of reduced or eliminatedriparian (streamside) vegetation. The removal ofriparian vegetation is the primary factor influenc-ing streambank stability. Historically, channelstraightening (channelization) was the primarymethod used to control streambank erosion.However, since the 1970s, riparian and in-streamhabitat restoration by natural or artificial meth-ods has grown in popularity because channel-ization typically caused problems, such as ero-sion and flooding dowstream. Natural resourceagencies throughout the Midwest have beenusing tree revetments as one type of streambankstabilization structure.What are tree revetments?Tree revetments are a series of trees laid in thestream along the eroding bank. They are de-signed to reduce water velocity, increase siltationwithin the trees, and reduce slumping of thestreambank. Tree revetments are not designed topermanently stabilize eroding streambanks. Theyshould stabilize the streambank until other stabi-lization techniques, such as tree plantings in theriparian area become established. Tree revet-ments are not designed to fix problems at awatershed level. Tree revetments should only beused if good land management practices areapplied in the watershed, for example fencingriparian areas from cattle use, maintaining bufferstrips between streams and row crops, or terrac-ing highly erodible row-crop fields.Outdated Publication, for historical use. CAUTION: Recommendations in this publication may be obsolete.3How are tree revetmentsconstructed?Tree revetments are constructed by anchoringfinely branched trees, like eastern red cedar at thebottom of an unstable streambank. Installationstarts at the downstream end of the erodedbank—at a point where the bank is stable. Eachtree is placed into the stream with the cut endpointing upstream. Trees are overlapped approxi-mately one-third and are anchored twice using aDuck- bill Anchor. Construction continues untilthe entire eroded surface is covered and the treerevetment is secured at a stable point upstream.What did this research document?The purpose of this research was to determinewhat effects tree revetments had on erosion anddeposition within a stream, and how these pro-cesses influenced stream fishes and aquaticinsects. The study was conducted on Kings Creek(Riley County) and West Creek (GreenwoodCounty), Kansas from 1994 through 1996. Revet-ment sites were chosen in conjunction with theKansas Forest Service, Kansas State UniversityAgricultural Experiment Station and CooperativeExtension Service and Kansas Department ofWildlife and Parks. Each revetment site wascompared to two control sites, one upstream andone downstream from the tree revetment loca-tion. While the controls had similar cross-sectionsto the tree revetment sites, they were differentbecause they had well-developed riparian corri-dors. Therefore, if similar results were foundamong the controls and tree revetment sites, itwas concluded that the tree revetments werefunctioning similar to a stable streambank with awell-developed riparian corridor.1816141210864200 10 20 30 40 50 60 70DISTANCE (FEET)HEIGHT OF STREAMBANK (FEET)Sample in 1994 prior to tree revetment installation at tree revetment locations.Sample in 1996KINGS CREEKn The control sites all had well-developedriparian corridors, as shown in the photoabove. There was little change in thechannel cross-section at the controls sitesfrom 1994 to 1996, as shown by therepresentative cross-section in the graph.Outdated Publication, for historical use. CAUTION: Recommendations in this publication may be obsolete.43025201510500 10 20 30 40 50 60DISTANCE (FEET)HEIGHT OF STREAMBANK (FEET)WEST CREEK (PRE-TREE REVETMENT INSTALLATION)n The tree revetment sites lacked a ripariancorridor and had accelerated erosionproblems, as shown in the photo above.The corresponding graph shows theeroding outside bend at 26 feet in height.n After tree revetment installation, banksbecame more gradual and the mainchannel of the stream was moved awayfrom the eroding bank, protecting thestreambank from excessive erosion. Thecorresponding graph illustrates how theslope of the eroding streambankdecreased, and how silt increased withinthe tree revetment.DISTANCE (FEET)HEIGHT OF STREAMBANK (FEET) 3025201510500 10 20 30 40 50 60Pre-Tree Revetment (Winter ‘94)Post-Tree Revetment (Spring ‘96)Tree RevetmentWEST CREEKOutdated Publication, for historical use. CAUTION: Recommendations in this publication may be obsolete.503691215WINTER ‘94PRE TREEREVETMENTSAMPLEPOST TREE REVETMENT SAMPLESSPRING ‘95 SUMMER ‘95 FALL ‘95 SPRING ‘96NUMBER OF FISH SPECIESKINGS CREEK Downstream ControlTree RevetmentUpstream Control0510152025NUMBER OF FISH SPECIESWEST CREEK Downstream ControlTree RevetmentUpstream ControlWINTER ‘94PRE TREEREVETMENTSAMPLEPOST TREE REVETMENT SAMPLESSPRING ‘95 SUMMER ‘95 SPRING ‘96n The number of fish species present atKings Creek and West Creek was notrelated to the establishment of the treerevetments. This is evident by the lack ofa distinct pattern in number of fishspecies present among the controls andtree revetment location.n Central stoneroller (top photo) were themost abundant fish present in KingsCreek. Central stonerollers are common instreams through eastern Kansas. Centralstonerollers feed primarily on algae andmicro-organisms associated with thestreambottom. Central stonerollers onlyget 6 to 8 inches long.n Orangespotted sunfish were the mostabundant fish present in West Creek.Orangespotted sunfish are in the samefamily of fish as bluegill and crappie, andusually feed on small aquatic insects andother fish. Orangespotted sunfish do notgrow much larger than 6 inches.Outdated Publication, for historical use. CAUTION: Recommendations in this publication may be obsolete.60.00.51.01.52.0WEST CREEK Downstream ControlTree RevetmentUpstream ControlAVERAGE LENGTH (IN.) OF ORANGESPOTTED SUNFISHWINTER ‘94PRE TREEREVETMENTSAMPLEPOST TREE REVETMENT SAMPLESSPRING ‘95 SUMMER ‘95 SPRING ‘960246810CATCH OF ORANGESPOTTED SUNFISHWEST CREEK Downstream ControlTree RevetmentUpstream ControlWINTER ‘94PRE TREEREVETMENTSAMPLEPOST TREE REVETMENT SAMPLESSPRING ‘95 SUMMER ‘95 SPRING ‘96n Catch of orangespotted sunfish declinedat all locations after installation of thetree revetment. Similar to catch of centralstonerollers in Kings Creek, catch oforangespotted sunfish was not influencedby the tree revetment. Average length oforangespotted sunfish remained similar atall locations before and after installation ofthe tree revetment.05101520253035CATCH OF CENTRAL STONEROLLERSKINGS CREEK Downstream ControlTree RevetmentUpstream ControlWINTER ‘94PRE TREEREVETMENTSAMPLEPOST TREE REVETMENT SAMPLESSPRING ‘95 SUMMER ‘95 FALL ‘95 SPRING ‘960.00.51.01.52.02.53.0AVERAGE LENGTH (IN.) OF CENTRAL STONEROLLERSKINGS CREEK Downstream ControlTree RevetmentUpstream ControlWINTER ‘94PRE TREEREVETMENTSAMPLEPOST TREE REVETMENT SAMPLESSPRING ‘95 SUMMER ‘95 FALL ‘95 SPRING ‘96n Catch of central stoneroller declinedslightly after installation of the treerevetment at the tree revetment andupstream control locations. Thus, it islikely that catch of central stonerollerswas influenced by a factor other than thetree revetment. Average length of centralstonerollers remained similar at alllocations before and after installation ofthe tree revetment.Outdated Publication, for historical use. CAUTION: Recommendations in this publication may be obsolete.70.00.10.20.30.40.50.60.70.8WEST CREEK Downstream ControlTree RevetmentUpstream ControlDIVERSITY INDEX FOR AQUATIC INSECTSWINTER ‘94PRE TREEREVETMENTSAMPLEPOST TREE REVETMENT SAMPLESSPRING ‘95 SUMMER ‘95 SPRING ‘960.00.10.20.30.40.50.60.70.8DIVERSITY INDEX FOR AQUATIC INSECTSKINGS CREEK Downstream ControlTree RevetmentUpstream ControlWINTER ‘94PRE TREEREVETMENTSAMPLEPOST TREE REVETMENT SAMPLESSPRING ‘95 SUMMER ‘95 FALL ‘95 SPRING ‘960.00.51.01.52.0SILTATION (OZ.)KINGS CREEK Downstream ControlTree RevetmentUpstream ControlWINTER ‘94PRE TREEREVETMENTSAMPLEPOST TREE REVETMENT SAMPLESSPRING ‘95 SUMMER ‘95 FALL ‘95 SPRING ‘960.00.20.40.60.81.0WEST CREEK Downstream ControlTree RevetmentUpstream ControlSILTATION (OZ.)WINTER ‘94PRE TREEREVETMENTSAMPLEPOST TREE REVETMENT SAMPLESSPRING ‘95 SUMMER ‘95 SPRING ‘96n Diversity of aquatic insects was variablein Kings Creek and West Creek, but wasnot related to the tree revetment. Overall,the tree revetments had no effect on thediversity of aquatic insects present.n The amount of siltation within KingsCreek (left) was generally lower at alllocations after installation of the treerevetment. Conversely, siltation increasedin West Creek at the tree revetmentlocation after installation. This is likelycaused by the tree revetments trappingsediment. Sediment trapping did notoccur on Kings Creek because the treerevetment was slightly above the waterlevel during normal flow.Outdated Publication, for historical use. CAUTION: Recommendations in this publication may be obsolete.8SummaryControl locations had well-established riparian corridors andrepresented areas with little streambank erosion. Therefore, iftree revetment locations were similar to control locations, wewould conclude that tree revetments stabilized banks compa-rable to areas with well-established riparian corridors. Ingeneral, tree revetments did not differ from control locations,thus, tree revetments appear to stabilize streambank erosion.Similarly, this research suggests that tree revetments do notenhance or reduce stream fish and aquatic insect communities. Itis likely that tree revetments can reduce localized sedimentationby trapping bank sluff behind the revetment.This study was conducted for two years and applied on twostreams. In addition, tree revetments were placed above thewater-level at normal flow. It is likely that results may varygiven different conditions. Nevertheless, the highest floodrecorded at Kings Creek occurred during 1995 and the treerevetment reduced the erosion potential of the flood. Treerevetments can provide short-term relief from streambankerosion until good land management practices are made in thewatershed.Frequently Asked QuestionsAs tree revetments increase in popularity many landowners andmanagers are asking a number of questions, such as:How long will the tree revetment last?It is unknown exactly how long a tree revetment will last. It hasbeen estimated to be about 10 to 15 years. However, this willdepend on how often the trees are in and out of the water.What type of tree should be used in tree revetments?Trees with many fine branches are the best at slowing nearbankcurrents, catching sediment carried in the stream, and catchingslump material from the bank. For this reason, Eastern red cedaris usually the best choice. Eastern red cedar is also more resistantto decay than hardwood trees.How much maintenance is required?The amount of maintenance required for tree revetments is goingto depend on several factors. For example, the frequency they aresubmerged in water, number and frequency of large floods, andhow well the ends are secured to the streambanks.Will tree revetments affect the fish community?The results from this study show that fish communities are notadversely affected by tree revetments.Are permits required to install tree revetments?Whether special permits are required or not will depend uponwhat county and state you are in. It is best to contact the U.S.Army Corps of Engineers, and your state Division of WaterResources.Will tree revetments stop erosion?Yes, results from this study have shown that localized streambankerosion can be reduced by tree revetments. However, to stoperosion for a long period of time (i.e., greater than 10 years),other methods must also be used, like large-scale watershedrestoration, revegetation of the riparian corridor, maintainingbuffer strips between row crops and the stream, and fencingcattle out of the stream.Do tree revetments clean the water?Water quality is generally related to problems in the watershedand typically tree revetments will not improve the overall waterquality of a stream. The most appropriate way to improve waterquality is to practice wise land use at the watershed level.Where can I get technical and financial assistance?Contact your local conservation district office, Kansas Depart-ment of Wildlife and Parks District Biologist, Kansas ForestService, or K-State Research and Extension for additionalinformation on tree-revetments, cost-share opportunities, ortechnical assistance.Where can I get additional information about tree revetmentsand other streambank stabilization techniques?n Tree Revetments for Streambank Stabilization. MissouriDepartment of Conservation, Streams for the Future, FisheriesDivision.n Wetland & Riparian Best Management Practices For KansasNo. 2—Tree Revetments. Wetland & Riparian Areas Program.K-State Research and Extension, Kansas Forest Service andKansas Department of Wildlife and Parks.n Wetland & Riparian Best Management Practices For KansasNo. 4—Willow Cutting. Wetland & Riparian Areas Program.K-State Research and Extension, Kansas Forest Service andKansas Department of Wildlife and Parks.n Wetland & Riparian Best Management Practices For KansasNo. 7—Tree and Shrub Planting. Wetland & Riparian AreasProgram. K-State Research and Extension, Kansas ForestService and Kansas Department of Wildlife and Parks.n Wetland & Riparian Best Management Practices For KansasNo. 9—Streambank & Shoreline Protection. Wetland &Riparian Areas Program. K-State Research and Extension,Kansas Forest Service and Kansas Department of Wildlife andParks.n Wiens, J.R. 1996. Effects of Tree Revetments on the Abiotic andBiotic Components in Two Kansas Streams. M.S. Thesis,Kansas State University, Manhattan. 90 pp.Authors: Jennifer R. Weins, Graduate Research Assistant, Division ofBiology, Christopher S. Guy, Adjunct Assistant Professor, Division ofBiology, Charles D. Lee, Extension Specialist, Wildlife, Animal Sciences& IndustryThe authors offer appreciation to F. Robert Henderson forgranting access to West Creek, Ron Klataske for granting accessto Kings Creek, and Konza Prairie Research Natural Area forallowing access to Kings Creek.The information in this document has been funded wholly orin part by the United States Environmental Protection Agency.The research was conducted at Kansas State University, Division ofBiology, Kansas Cooperative Fish and Wildlife Research Unit. The KansasCooperative Fish and Wildlife Research Unit is jointly supported by theKansas Department of Wildlife and Parks, Kansas State University, U.S.Geological Survey—Biological Resources Division, and the WildlifeManagement Institute.This and other publications from Kansas State University are available onthe World Wide Web at: http://www.oznet.ksu.eduContents of this publication may be freely reproduced for educationalpurposes. All other rights reserved. In each case, credit Jennifer R.Wiens, Christopher S. Guy, Charles D. Lee, Streambank Revetment,Kansas State University, September 1997.•UNITED STATES•ENVIRONMENTAL PROTECTIONAGENCYKansas State University Agricultural Experiment Stationand Cooperative Extension ServiceMF-2294 September 1997It is the policy of Kansas State University Agricultural Experiment Station andCooperative Extension Service that all persons shall have equal opportunity andaccess to its educational programs, services, activities, and materials withoutregard to race, color, religion, national origin, sex, age or disability. Kansas StateUniversity is an equal opportunity organization. Issued in furtherance of Coopera-tive Extension Work, Acts of May 8 and June 30, 1914, as amended. Kansas StateUniversity, County Extension Councils, Extension Districts, and United StatesDepartment of Agriculture Cooperating, Marc A. Johnson, Director.File code: Engineering 4-2 9-97—2MOutdated Publication, for historical use. CAUTION: Recommendations in this publication may be obsolete.

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