Improving the Urban Stream Restoration Effort: Identifying Critical Form and Processes Relationships

Abstract

Stream restoration projects are often based on morphological form or stream type and, as a result, there needs to be a clear tie established between form and function of the stream. An examination of the literature identifies numerous relationships in naturally forming streams that link morphologic form and stream processes. Urban stream restoration designs often work around infrastructure and incorporate bank stabilization and grade control structures. Because of these imposed constraints and highly altered hydrologic and sediment discharge regimens, the design of urban channel projects is rather unclear. In this paper, we examine the state of the art in relationships between form and processes, the strengths and weaknesses of these existing relationships, and the current lack of understanding in applying these relationships in the urban environment. In particular, we identify relationships that are critical to urban stream restoration projects and provide recommendations for future research into how this information can be used to improve urban stream restoration design. It is also suggested that improving the success of urban restoration projects requires further investigation into incorporating process-based methodologies, which can potentially reduce ambiguity in the design and the necessity of using an abundant amount of in-stream structures.

Monitoring the channel process of a stream restoration project in an urbanizing watershed: a case study of Kelley Creek, Oregon, USA

“…The characteristics of the reference reaches can be used as templates for the new channel designs. Reference reaches are assumed to be similar in sediment source, dynamic equilibrium, climate and geology and form and process (Niezgoda and Johnson, 2005).…”

Urbanization Effects on Watershed Hydrology and In-Stream Processes in the Southern United States

“…Simon's channel evolution model [189] provides a general framework for a stream reach's geomorphological response to disturbance, particularly for stream channelization. There is a growing need for channel evolution models that are specifically designed to capture the complexities of urban watersheds and account for the differences in physiographic setting [9].…”

“…Recent urbanization has increased the potential for hydrological alterations and channel disturbances along streams. Urban stream responses may differ across physiographic regions because of differences in climatic inputs, vegetation, geology, slope, stream geomorphology, and hydrologic processes [9]. There is a growing need to synthesize regional hydrologic responses to urbanization to improve the understanding of stream response to land use change.…”

Predicting wetted width in any river at any discharge

“…Applications include providing information for habitat assessments (Jowett, 1998;Rosenfeld et al, 2007), sediment transport estimation (Goodwin, 2004) and fl ood discharge estimation (Wharton, 1992;Ashmore and Sauks, 2006). Many studies have used downstream hydraulic geometry in relation to channel dimensions for river restoration (Niezgoda and Johnson, 2005), gemorphological analysis (Burge, 2004) or to assess the differences in stream channel dimensions between urban and rural streams (Doll et al, 2007).…”