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Comparison of Three Macroinvertebrate Sampling Methods for Use in Assessment of Water Quality Changes in Flashy Urban Streams
Citation:
Yeardley, R., S. Jacobs, K. Fritz, AND W. Thoeny. Comparison of Three Macroinvertebrate Sampling Methods for Use in Assessment of Water Quality Changes in Flashy Urban Streams. Journal of Environmental Protection. Scientific Research Publishing, Inc., Irvine, CA, 11(8):585-609, (2020). https://doi.org/10.4236/jep.2020.118035
Impact/Purpose:
The USEPA and other local and state organizations are involved in urban stream restoration and/or green infrastructure projects that affect stream water quality. Measuring success of such projects involves measuring water quality before and after restoration. A widely used, established means of assessing water quality through bioassessment of macroinvertebrate communities. However, many of the widely used sampling methods, such as nets and fixed-area grab samplers (Hess, Surber) require significant stream flow to be effective. Many urban streams have a flashy flow regime, with these streams existing as a series of pools for much of the year, interspersed with flooding events. We evaluated 3 sampling methods (modified Hester-Dendy, gravel tray, and bucket grab samplers) with respect to 3 criteria, to see which had the most promise to fill this methods gap for bioassessment of flashy urban streams. The bucket grab sampler clearly performed best with respect to all 3 criteria. The results of this work will be of interest to partners in local, state, and regional governments (including the Ohio EPA) as well as non-governmental organizations, which have a need to monitor stream water quality on an ongoing or project-related basis.
Description:
The unique challenges associated with sampling of macroinvertebrates in flashy urban streams create a methods gap. These streams form isolated pools for much of the year, interspersed with spates that scour and deposit excessive amounts of sediment. Commonly used stream grab sampling methods, such as nets and Hess and Surber fixed-area samplers, work well in wadable streams with perennial flow. Deployed samplers (Hester-Dendy, gravel tray) can be used in waters with or without flow. We evaluated three methods which don’t require stream flow: modified Hester-Dendy (MHD), gravel tray, and bucket (a type of cylinder grab sample method), for their potential use in bioassessment of a project involving daylighting of a 180-m culvert on Congress Run, a flashy urban tributary to Mill Creek in Cincinnati, Ohio. Method efficacy was measured using three criteria: usability (level of effort and recoverability of samplers), variability, and community retrieval completeness. The bucket method required the lowest level of effort and had the highest sample recovery. The bucket sampler had the lowest variability for most metrics, including the critical metric of taxa richness, with a coefficient of variation (CV) of 20.9%. The MHD and tray samplers had taxa richness CVs of 42.9% and 53.9%, respectively. The bucket sampler also had the lowest CV (27.4%) for a multi-metric index. The bucket sampler performed best with respect to community retrieval completeness, with higher pooled and average taxa richness. The total number of taxa collected from all the replicate bucket grab samples (42) was greater than that collected by the HD and tray samplers combined (27). Multivariate analyses showed significant grouping with respect to methods and location. This study supports the bucket grab sampler method as a candidate for sampling of flashy urban streams.
URLs/Downloads:
DOI: Comparison of Three Macroinvertebrate Sampling Methods for Use in Assessment of Water Quality Changes in Flashy Urban Streams