Streambank stabilization practices protect banks of streams or constructed channels, and shorelines of lakes, reservoirs, or estuaries to reduce erosion. Methods used include soil bioengineering and structural measures. Most measures are primarily used in streams and rivers, and for shoreline protection. Streambank stabilization is considered an in-channel practice.
Figure 20. Streambank stabilization. Credit: FABE, The Ohio State University.
Soil bioengineering measures include:
- live stakes
- live fascines(bundle of rods, sticks, or plastic pipes bound together)
- vegetated geogrids
- live cribwall/lunker
- reed clumps
- coconut fiber rolls
Structural measures include:
- rock riffle
- tree revetments
- boulder revetment
- dormant post planting
- rock gabions(a wirework container filled with rock, broken concrete, or other material)
- rock riprap
- rock gabions
- stream barbs/bendway weir
Other measures are floodplain establishment measures, such as two-stage ditches and flattening bank side slopes.
Streambank stabilization can be used where channel or impoundment banks are vulnerable due to instability. It can also be used where relatively simple erosion and stability control measures will solve the problem. Care should be taken so that the failure of these measures will not create a hazard that can result in serious damage to property or loss of life.
This standard does not apply to more complex bank erosion problems on major bodies of water such as Lake Erie and its major bays.
Beneﬁts of streambank stabilization include:
- reducing loss of land, and reducing damage to land uses or other facilities adjacent to the banks.
- maintaining the ﬂow or storage capacity of the channel or impoundment.
- reducing the downstream eﬀects of sediment resulting from bank erosion.
- maintaining or restoring channel meanders that enhance stream conditions.
- improving or enhancing the stream corridor for ﬁsh and wildlife habitat, aesthetics, and recreation.
- The effectiveness and water quality beneﬁts of streambank stabilization measures are very site-speciﬁc.
- The primary purpose of streambank stabilization measures is to prevent or reduce soil erosion associated with mass bank failures and scour of streambanks associated with saturated conditions and ﬂowing water associated with runoff and/or ﬂow in a channel such as a stream or ditch.
- Shoreline stabilization measures are often associated with preventing and reducing soil erosion associated with wave actions on the shore.
- Pesticide and nutrient removal is likely to be less than 50 percent, reducing only a small percentage of the total load in runoff and drainage in areas where most of the discharge is subsurface drainage.
- Measures should be installed according to a site-speciﬁc plan (inventory and evaluation, resource management system, etc.) based on a ﬁeld site assessment. Streambank and shoreline protection should be performed in compliance with the permits or approval as required by local, state, or federal agencies.
- Permits include, but are not limited to, State 401 Clean Water Certiﬁcation from the Ohio EPA, nationwide or individual permits under Section 404 of the Clean Water Act from the U.S. Corps of Engineers, and local ﬂoodplain management permits.
- Streambank and shoreline stabilization practices should be developed by a qualiﬁed engineer or land improvement contractor.
- Streambank instability is often associated with upstream—and in some cases downstream—watershed activities that are beyond the control of an individual stakeholder. Therefore, eﬀective solutions might require participation and cooperation of multiple stakeholders in a watershed.
- Costs are site-speciﬁc and will depend on the size and type of streambank stabilization measures needed at a location.
- In some cases, cost-sharing funds might be available, depending on the size of the needed bank stabilization and the type of measures used.
- The root mass of living plants stabilizes the soil. Also, transpiration by the living plants reduces the soil moisture.
- Measures such as rock riprap harden the banks and prevent scour.
- Rock structures such as barbs deﬂect ﬂow away from the banks.
- Flattening side slopes reduces bank instability.
- Floodplain establishment reduces shear stresses on the bed and banks.
There is some uncertainty associated with designing bank stabilization measures to account for all the dynamic variability of channel and shoreline conditions. Also, it is diﬃcult and usually costly to establish self-sustaining systems. Therefore, bank stabilization measures usually require some level of maintenance.
Extensive design details are available at Ohio NRCS Standard 580: Streambank and Shoreline Stabilization