Elevated levels of enterococci bacteria, an indicator of fecal pollution, are routinely detected in the surf zone at Huntington State and City Beaches in southern California. A multidisciplinary study was carried out to identify sources of enterococci bacteria landward of the coastline. We find that enterococci bacteria are present at high concentrations in urban runoff, bird feces, marsh sediments, and on marine vegetation. Surprisingly, urban runoff appears to have relatively little impact on surf zone water quality because of the long time required for this water to travel from its source to the ocean. On the other hand, enterococci bacteria generated in a tidal saltwater marsh located near the beach significantly impact surf zone water quality. This study identifies a potential tradeoff between restoring coastal wetlands and protecting beach water quality and calls into question the use of ocean bathing water standards based on enterococci at locations near coastal wetlands.

Many regions have turned to low impact development technologies (LIDs), which are implemented to restore the changes in stormwater runoff that have resulted from urbanization. Green roofs are one typical type of LID. Until now, many studies have validated their roles in managing urban stormwater runoff. However, they have also revealed that the performance of green roofs largely varies with their design configuration, as well as their hydro-climatic exposure. The objectives of this review paper are to statistically synthesize the effects of the influential factors, including design and hydrologic variables, on green roof performance and to explore their effects in different climatic zones. The review’s results confirm the differences in the influential variables and, thus, the performance of green roofs in different climatic zones. These are the barriers to knowledge translation among engineering designers, stormwater managers, and policymakers in different climatic zones when implementing green roofs. Consequently, region- or site-specific studies are necessary to implement green roofs with confidence.

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This study investigates the processes and characteristics of solids removal in two types of permeable pavement: UNI Eco-Stone and porous asphalt. The mechanisms and processes behind solids removal within permeable pavement structures was studied for these two types of permeable pavements using both field installations and laboratory experiments. Results from the study showed that both pavement types are capable of excellent total suspended solids removal, in the range of 90 to 96% removal of solids from influent. Particle size distribution analysis of accumulated sediment within the pavement structure and in the influent and effluent showed that the particles in the effluent of the pavements are substantially finer than that in the influent. Laboratory results involving no crust formation indicated that, although solids removal occurs throughout the entire structure, the "sieving action" occurs primarily at the geotextile interface.

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A novel passive gas diffusion sampler (PGDS) combines sampling, storage and direct injection into a single gas chromatograph (GC). The sampler has a 4.5 mL internal volume when deployed, is easy to operate, and eliminates sample-partitioning. The associated GC method analyzes for a large, dynamic sampling range from a single, small volume injection. Dissolved gases were separated on parallel Rt-Molsieve 5A and Rt-Q-PLOT columns and eluted solutes were quantified using a pulse discharge helium ionization detector (PD-HID). The combined sampling and analytical method appears to be less prone to systematic bias than conventional sampling and headspace partitioning and analysis. Total dissolved gas pressure used in tandem with the PGDS improved the accuracy of dissolved gas concentrations. The incorporation of routine measurements of dissolved biogeochemical and permanent gases into groundwater investigations will provide increased insight into chemical and biological processes in groundwater and improve chemical mass balance accuracy.

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