Multi-Scale Geomorphic Assessment Approach for Streams in the Southern Illinois Region: Case Study, Big Creek Watershed, Pulaski and Union Counties, Illinois

Keefer, Laura L.

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https://hdl.handle.net/2142/103432 Copy

Description

Title

Multi-Scale Geomorphic Assessment Approach for Streams in the Southern Illinois Region: Case Study, Big Creek Watershed, Pulaski and Union Counties, Illinois

Author(s)

Keefer, Laura L.

Issue Date

2006-04-17

Keyword(s)

• geomorphic assessment
• Illinois
• Cache River
• Big Creek
• geomorphology

Geographic Coverage

• Southern Illinois
• Cache River
• Union County, Illinois
• Pulaski County, Illinois
• Big Creek

Abstract

Human alteration of stream channels and land use initiates responses in a fluvial system that can increase flooding, erosion, and sedimentation, which, in turn, impact aquatic habitat, property, and water quality. Geomorphic assessment approaches have been developed to evaluate channel response to disturbances for various regions of the United States and there is concern regarding the appropriateness of applying them in regions for which they were not developed, particularly Illinois. Channel responses to disturbances tend to be more subtle in Illinois as compared to the dramatic responses in the mountainous northwest, arid southwest, and coastal plains. Also, channel disturbance issues are complex and dynamic, consequently the evaluation of these issues requires extensive training and formal research experience. Due to pressure by policy makers and resource managers for rapid assessments and natural channel designs for stream restorations, some assessment approaches have been developed and applied by non-geomorphologists and extended beyond credible use. Lack of standardization between approaches has proven difficult to compare disturbance response mechanisms within and between physiographic regions, as well as establishing long-term research of these mechanisms. A standardized, systematic geomorphic assessment approach for evaluating past conditions, extant character, and potential future adjustments of stream channels in Illinois was developed and evaluated. The methodology draws from components of approaches developed in the United States. The approach was applied to the Big Creek watershed in the Cache River Basin in the southern region of Illinois – a fluvial system that has been severely impacted both directly and indirectly by human activities. The geomorphic assessment approach has three levels of investigation that incorporates temporal- and spatial-scale analysis, standardizes the systematic collection of data, compares and contrasts multiple lines of evidence to characterize the watershed and channels, and utilizes three approaches to evaluate prevailing channel process response mechanisms to infer potential future channel adjustments. Several components overcame inconsistent datasets found in Big Creek and integrated multi-scale information to infer future several channel adjustment processes. The results for the case study watershed, Big Creek, revealed that the complex geology and multiple human disturbances has produced four separate channel responses that will require separate, but integrated, attention of the watershed and channel reaches.

Type of Resource

text

Language

en

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http://hdl.handle.net/2142/103432

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