Stream Restoration and Floodplain Reconnection Using All Wood Structures Harvested from the Site
Joe Berg
Biohabitats, Inc.
Baltimore, MD
Authors: Joe Berg and Doug Streaker
The use of wood in stream restoration structures is a logical refinement of stream restoration techniques. Wood is a natural renewable resource, is less costly than the rock currently used, and was a common feature in stream stability across North America prior to extirpation of beaver, European colonization, and removal of wood from streams to manage flooding risks. With few exceptions in stream restoration (notably in the Northwest), wood has played a secondary role to rock in bed and bank stability design. Adding wood to riffle features to improve their habitat quality, using buried wood as a bank stabilization and habitat improvement feature, using rootwads to attenuate velocities and improve bank cover are all highly valued applications of wood in stream restoration. In general, rock weir features and boulder walls are the designers ‘go to’ solutions in high flow conditions.
The approach we have undertaken, building wood and earth plugs in incised, over-widened, and disconnected stream channels creates lateral floodplain reconnection, deeper stream flow to support better aquatic life habitat and connectivity, and reduced sediment and nutrient loading. In addition, this approach is regenerative and sustainable in a forested landscape. Wood production rates are higher than decomposition rates, floodplain reconnection reduces in-stream shears and supports accumulation of wood and leaf material, and the restored groundwater support riparian and floodplain wetland community development. All these functional uplift improvements for a fraction of the cost of stream restoration using rock.
We will describe two recently completed projects totaling more than 20,000-ft that use engineered wood structures. One project consisted of ~4300-ft of a headwater stream system with a drainage area of ~250 ac. The second project, on the same stream, consisted of ~18,000-ft of a 3rd order stream with a drainage area of ~9 square miles (5700 acres). We will discuss our design approach, the regulatory experience, and our experience with construction management using two different contractors. Our goal is to stimulate more projects of this type by helping the design and construction community to build capacity for this type of truly sustainable ecological restoration.
About Joe Berg
Joe is an ecosystems ecologist with more than 30 years experience in the assessment and analysis of natural resources, documentation, permitting, and the preparation and implementation of restoration plans. The focus of his efforts include restoration of integrated stream, wetland and floodplain functions as a means to deliver ecosystem services to society, increase natural capital, and integrate local community needs with an appreciation of natural resource values.