Soil bioretention protects juvenile salmon and their prey from the toxic impacts of urban stormwater runoff

Abstract

Green stormwater infrastructure (GSI), or low impact development, encompasses a diverse and expanding portfolio of strategies to reduce the impacts of stormwater runoff on natural systems. Benchmarks for GSI success are usually framed in terms of hydrology and water chemistry, with reduced flow and loadings of toxic chemical contaminants as primary metrics. Despite the central goal of protecting aquatic species abundance and diversity, the effectiveness of GSI treatments in maintaining diverse assemblages of sensitive aquatic taxa has not been widely evaluated. In the present study we characterized the baseline toxicity of untreated urban runoff from a highway in Seattle, WA, across six storm events. For all storms, first flush runoff was toxic to the daphniid Ceriodaphnia dubia, causing up to 100% mortality or impairing reproduction among survivors. We then evaluated whether soil media used in bioretention, a conventional GSI method, could reduce or eliminate toxicity to juvenile coho salmon (Oncorhynchus kisutch) as well as their macroinvertebrate prey, including cultured C. dubia and wild-collected mayfly nymphs (Baetis spp.). Untreated highway runoff was generally lethal to salmon and invertebrates, and this acute mortality was eliminated when the runoff was filtered through soil media in bioretention columns. Soil treatment also protected against sublethal reproductive toxicity in C. dubia. Thus, a relatively inexpensive GSI technology can be highly effective at reversing the acutely lethal and sublethal effects of urban runoff on multiple aquatic species.

Coho salmon spawner mortality in western US urban watersheds: bioinfiltration prevents lethal storm water impacts

“…), juvenile coho salmon and their macroinvertebrate prey (McIntyre et al . ), and adult coho spawners (this study). Bioretention is therefore a promising clean water technology from the standpoint of installation cost, reliability, reproducibility and scalability.…”

“…McIntyre et al . ), the experimental soil columns used here effectively prevented the acutely lethal toxicity of run‐off from a dense urban arterial road. This extends the range of aquatic species and life stages that demonstrably benefit from storm water bioinfiltration.…”

Highway runoff quality models for the protection of environmentally sensitive areas

“…Meteorological as well as traffic study data were collated for these events as input data used to train predictive neural networks models for the estimation of the key parameters needed to define the statistical distribution of seasonal event mean TSS and heavy metals concentrations, as well as the mean annual unit area loads of several commonly reported heavy metal species. Accurate predictive tools are needed to estimate the lifetime loading of heavy metals so that appropriately selected and sized treatment media can be implemented for the protection of environmentally sensitive areas (Schmueli, 2010;McIntyre et al, 2015;Trenouth and Gharabaghi, 2015a) (see Fig. 5).…”

“…Researchers have highlighted the importance of heuristic models capable of predicting pollutant concentrations in highway runoff, particularly for the design of stormwater bioretention and other treatment approaches aimed at protecting environmentally sensitive areas (Oreskes et al, 1994;Maniquiz et al, 2010;Luell Opher and Friedler, 2010;LeFevre et al, 2014;Stagge et al, 2012;Li, 2015;McIntyre et al, 2015;Pan and Miao, 2015;Huber et al, 2016). In North America, the US Interstate System accounts for over 75,000 km of highways, and the Tran-Canada Highway accounts for an additional 7821 km of road length (CCMRTHS, 2009;USDOT and FHWA, 2014).…”

“…Multi-lane, high-volume roadways are one of the leading causes of watercourse degradation and impairment in the United States and elsewhere (Crabtree et al, 2006;EPA, 2010;Francey et al, 2010;Istenič et al, 2012;McIntyre et al, 2015;Pan and Miao, 2015). Impairment by roadways includes the loss or degradation of aquatic habitat, increased water treatment costs for human consumption and irrigation, as well as the loss of recreational opportunities, resulting from a combination of increased runoff volumes and pollutant loading (Bäckstrom et al, 2006;Butler and Vasconcelos, 2015;Kayhanian et al, 2012;Moghadas et al, 2015).…”