STREAM IMPROVEMENTS AND FISH RESPONSE: A BIO‐ENGINEERING ASSESSMENT¹

Abstract

Human modifications of natural streams in the name of habitat improvement take various forms, and the impacts of those improvements, both positive and negative, vary by orders of magnitude from stream to stream. The positive impacts are achieved through careful and timely planning, design, installation and monitoring of projects. Negative impacts are the results of rush jobs dictated by available money, a lack of consideration for limiting factors, untrained and inexperienced personnel, force‐fitting structures instead of bending the flow, lack of a watershed plan, poor communication and cooperation among disciplines, not using the team approach, and single habitat solutions which neglect diversity and artificial constraints. These problems are discussed from various perspectives, but emphasis on an integrated, bioengineering approach is threaded throughout the discussion of the problems and benefits associated with stream improvements and fish response. A general systems approach is presented which uses common language as a focal point for interdisciplinary communication, which is one of the major problems in resource management. Various conceptual models are discussed to describe system complexities, and factors which constrain project evaluation in terms of biological, physical, economic and other components. Conclusions about why some projects are successful, while others are not, are followed by recommendations for concerted and diversified efforts to improve our success in stream stewardship.

Evaluation of instream habitat enhancement options using fish habitat simulations: case-studies in the river Pas (Spain)

“…These actions are best carried out through a formally planned project, with multiple objectives (Gardiner 1991) and directed by multidisciplinary teams using a bioengineering assessment (Orsborn and Anderson 1986). Firstly, an evaluation of fish populations and their habitat should be done, taking into account the five main components of fish habitat, namely: spawning areas, food-production areas, refuge zones, flow regimes and water quality (Garcı´a de Jalo´n 1995).…”

Effectiveness of Habitat Manipulation for Wild Salmonids in Wyoming Streams

“…White and Brynildson (1967) stressed that planning for stream improvement projects must consider how the whole stream functions. Platts and Rinne (1985) decried a lack of long‐term scientific research on stream improvement from a watershed standpoint, and Orsborn and Anderson (1986) called for an integrated, bioengineering approach to project planning. More recently, Stroud (1992), Beschta et al (1994), and have suggested a watershed‐oriented approach with emphasis on correcting abusive land‐use practices rather than resorting to instream structures.…”

Stream corridor management in the Pacific Northwest: I. Determination of stream-corridor widths

“…Research has focused on selected environmental factors affecting riparian ecosystems, and management methods have evolved from this research which emphasize that single dimension focus. Moreover, this single-dimension perspective has extended to the implementation and planning aspects of stream management (Orsborn and Anderson 1986). Our research indicates that practical determinations of stream corridor widths can be efficiently and easily made using a simple field survey of select reaches of a stream system combined with an analysis of soils, vegetation, physiography, and land-use characteristics.…”