Measuring Streambank Erosion: A Comparison of Erosion Pins, Total Station, and Terrestrial Laser Scanner

Daniel T Myers,James N Mcnair,Richard R Rediske

doi:10.3390/w11091846

Abstract

Streambank erosion is difficult to quantify; models and field methods are needed to assess this important sediment source to streams. Our objectives were to (1) evaluate and compare three techniques for quantifying streambank erosion: erosion pins, total station, and laser scanning, (2) spatially assess streambank erosion rates in the Indian Mill Creek watershed of Michigan, USA, and (3) relate results with modeling of nonpoint source pollution. We found large absolute and relative errors between the different measurement techniques. However, we were unable to determine any statistically significant differences between techniques and only observed a correlation between total station and laser scanner. This suggests that the three methods have limited comparability and differences between measurements were largely not systemic. Further, the application of each technique should be dependent on site conditions, project goals, desired resolution, and resources. The laser scanner collected high-resolution data on clear, barren streambanks, but the erosion pin and total station were more representative of complex vegetated banks. Streambank erosion rates varied throughout the watershed and were influenced by fluvial processes. We estimate that streambank erosion contributed 28.5% of the creek’s total sediment load. These findings are important to address sources of watershed impairments related to sedimentation, as choosing an applicable technique for individual purposes can help reduce the challenges and costs of a streambank erosion study.

Highlights

Sediment pollution is a major concern for streams throughout the United States [1]
There was no discernible relationship between undercut banks and total station results biased toward deposition, possibly because the bias from undercut banks was relatively small compared to the spread of the data
We found substantial absolute and relative errors in comparisons between measurement techniques, we were unable to detect significant differences, and found a significant correlation only between total station and laser scanner data

Summary

Introduction

Sediment pollution is a major concern for streams throughout the United States [1]. It causes widespread degradation of aquatic habitat and reduces suitability for fish and macroinvertebrate communities [1,2,3]. Sediment can enter a stream through many pathways, but the dominant pathway is often streambank erosion [4,5]. Understanding the dynamic nature of streambanks is important to shoreline landowners threatened by retreating banks, water quality managers, and geomorphologists [8]. It is important for projects involving stream restoration and Total

Objectives

Methods

Results

Discussion

Conclusion