Classifying Stream Restoration Projects and Understanding Created Channel Types - Two New River Management Design Tools

Two systems are presented to help guide the design of river management projects. There are many tools available to the stream restoration designer. For example, a range of old and new analytical, empirical, and analog techniques are available for creating different components of projects such as design flows, channel geometry, and habitat features. Project goals, scope, physical site constraints, ecological risks, and societal acceptance make up the core of every project, and often dictate the level of design that is required and possible. Using these five characteristics, projects can be classified as routine, moderate, or comprehensive, which in turn can be used to guide the appropriate level of design. This paper introduces this project classification system, describing how the classification is done and illustrating how it may be used to guide design. The term "stream restoration" is applied to a wide range of project types that include routine bank stabilization efforts, projects that are moderate in scope such as creating naturalistic open channels, and comprehensive ecological restoration to preserve the processes that form natural habitat. Several open channel types can be designed including unnatural rigid boundary channels, semi-natural form channels that replicate the morphology of a natural channel, and natural process channels that preserve the processes of natural alluvial systems. Each channel type has separate design and construction procedures, and has different potential for ecological recovery. The geomorphic, hydraulic, sediment stability/transport, and ecological characteristics of each channel type is evaluated and compared to help clarify the merit of various design and restoration philosophies. This paper provides a detailed description of each of these created channel types and provides an example of each. The created channels classification illustrates the important role of multi-discipline design teams with expertise in hydrology, engineering, fluvial geomorphology, ecology, and social sciences. The practitioners and regulatory agencies can then use this classification of channel types and project complexity types to guide restoration expectations.