Stanley Grant

Adapting Urban Water Systems to a Changing Climate: Lessons from the Millennium Drought in Southeast Australia

Publisher: American Chemical Society (ACS)

Date: 15-05-2013

DOI: 10.1021/ES400618Z

Factoring stream turbulence into global assessments of nitrogen pollution

Publisher: American Association for the Advancement of Science (AAAS)

Date: 16-03-2018

DOI: 10.1126/SCIENCE.AAP8074

Abstract: A combination of physical transport processes and biologically mediated reactions in streams and their sediments removes dissolved inorganic nitrogen (DIN) from the water. Although stream chemistry and biology have been considered the dominant controls on how quickly DIN is removed, Grant et al. show that physics is what sets the limits on removal rates of nitrate (a component of DIN). Residence time in the hyporheic zone (the region below the sediment surface where groundwater and surface water mix) determines the maximum rate at which nitrate can be removed from stream water. Nevertheless, at local scales, chemistry and biology modify how closely to that maximum rate removal occurs. Science , this issue p. 1266

Microlayer enrichment in natural treatment systems: linking the surface microlayer to urban water quality

Publisher: Wiley

Date: 11-12-2015

DOI: 10.1002/WAT2.1128

Abstract: Natural treatment systems ( NTS ), such as constructed wetlands and stormwater ponds, are multibenefit, multidisciplinary approaches to sustaining water resources and reducing contaminant loading to urban streams. Surficial thin films (called surface microlayers) are not well characterized in NTS , but may have important implications for ecosystems, public health, and pollutant fate and transport. We present results from a case study evaluating microlayer contaminant partitioning across 4 NTS in Melbourne, Australia. To our knowledge, this study provides the first direct evidence for microlayer formation and contaminant enrichment (total petroleum hydrocarbons and trihalomethanes) in NTS . Contaminated microlayers were detected in the three most stable NTS , with stability defined relative to wind speed. Fluorescent‐dissolved organic matter profiles differed between microlayer and subsurface water in these systems, suggesting that fluorescence‐based techniques are useful for microlayer detection. Although in idual fluorophores were not consistently associated with specific contaminants, fluorescence ratios were useful for identifying likely contaminant source waters, including road‐runoff and irrigation water from nearby green spaces. We evaluate our case study in light of what is known about surface microlayers in analogous systems (e.g., oceans, estuaries, and lakes), in order to identify existing research gaps and future opportunities. WIREs Water 2016, 3:269–281. doi: 10.1002/wat2.1128 This article is categorized under: Engineering Water Sustainable Engineering of Water Engineering Water Water, Health, and Sanitation Science of Water Water Quality

Taking the “Waste” Out of “Wastewater” for Human Water Security and Ecosystem Sustainability

Publisher: American Association for the Advancement of Science (AAAS)

Date: 10-08-2012

DOI: 10.1126/SCIENCE.1216852

Abstract: Humans create vast quantities of wastewater through inefficiencies and poor management of water systems. The wasting of water poses sustainability challenges, depletes energy reserves, and undermines human water security and ecosystem health. Here we review emerging approaches for reusing wastewater and minimizing its generation. These complementary options make the most of scarce freshwater resources, serve the varying water needs of both developed and developing countries, and confer a variety of environmental benefits. Their widespread adoption will require changing how freshwater is sourced, used, managed, and priced.

Unifying Advective and Diffusive Descriptions of Bedform Pumping in the Benthic Biolayer of Streams

Publisher: American Geophysical Union (AGU)

Date: 27-10-2020

DOI: 10.1029/2020WR027967

Effective diffusivity and mass flux across the sediment‐water interface in streams

Publisher: American Geophysical Union (AGU)

Date: 05-2012

DOI: 10.1029/2011WR011148

Variation in reach-scale hydraulic conductivity of streambeds

Publisher: Elsevier BV

Date: 04-2016

DOI: 10.1016/J.GEOMORPH.2016.02.001

Flipping the thin film model: Mass transfer by hyporheic exchange in gaining and losing streams

Publisher: American Geophysical Union (AGU)

Date: 10-2016

DOI: 10.1002/2016WR018972

From Rain Tanks to Catchments: Use of Low-Impact Development To Address Hydrologic Symptoms of the Urban Stream Syndrome

Publisher: American Chemical Society (ACS)

Date: 10-09-2015

DOI: 10.1021/ACS.EST.5B01635

Abstract: Catchment urbanization perturbs the water and sediment budgets of streams, degrades stream health and function, and causes a constellation of flow, water quality, and ecological symptoms collectively known as the urban stream syndrome. Low-impact development (LID) technologies address the hydrologic symptoms of the urban stream syndrome by mimicking natural flow paths and restoring a natural water balance. Over annual time scales, the volumes of stormwater that should be infiltrated and harvested can be estimated from a catchment-scale water-balance given local climate conditions and preurban land cover. For all but the wettest regions of the world, a much larger volume of stormwater runoff should be harvested than infiltrated to maintain stream hydrology in a preurban state. Efforts to prevent or reverse hydrologic symptoms associated with the urban stream syndrome will therefore require: (1) selecting the right mix of LID technologies that provide regionally tailored ratios of stormwater harvesting and infiltration (2) integrating these LID technologies into next-generation drainage systems (3) maximizing potential cobenefits including water supply augmentation, flood protection, improved water quality, and urban amenities and (4) long-term hydrologic monitoring to evaluate the efficacy of LID interventions.

Shifts in dissolved organic matter and microbial community composition are associated with enhanced removal of fecal pollutants in urban stormwater wetlands

Publisher: Elsevier BV

Date: 06-2018

DOI: 10.1016/J.WATRES.2018.03.020

Abstract: Constructed stormwater wetlands provide a host of ecosystem services, including potentially pathogen removal. We present results from a multi-wetland study that integrates across weather, chemical, microbiological and engineering design variables in order to identify patterns of microbial contaminant removal from inlet to outlet within wetlands and key drivers of those patterns. One or more microbial contaminants were detected at the inlet of each stormwater wetland (Escherichia coli and Enterococcus > Bacteroides HF183 > adenovirus). Bacteroides HF183 and adenovirus concentrations declined from inlet to outlet at all wetlands. However, co-removal of pathogens and fecal indicator bacteria only occurred at wetlands where microbial assemblages at the inlet (dominated by Proteobacteria and Bacteriodetes) were largely displaced by indigenous autotrophic microbial communities at the outlet (dominated by Cyanobacteria). Microbial community transitions (characterized using pyrosequencing) were well approximated by a combination of two rapid indicators: (1) fluorescent dissolved organic matter, and (2) chlorophyll a or phaeophytin a fluorescence. Within-wetland treatment of fecal markers and indicators was not strongly correlated with the catchment-to-wetland area ratio, but was diminished in older wetlands, which may point to a need for more frequent maintenance.

Bedforms as Biocatalytic Filters: A Pumping and Streamline Segregation Model for Nitrate Removal in Permeable Sediments

Publisher: American Chemical Society (ACS)

Date: 27-08-2015

DOI: 10.1021/ACS.EST.5B01941

Abstract: Bedforms are a focal point of carbon and nitrogen cycling in streams and coastal marine ecosystems. In this paper, we develop and test a mechanistic model, the "pumping and streamline segregation" or PASS model, for nitrate removal in bedforms. The PASS model dramatically reduces computational overhead associated with modeling nitrogen transformations in bedforms and reproduces (within a factor of 2 or better) previously published measurements and models of biogeochemical reaction rates, benthic fluxes, and in-sediment nutrient and oxygen concentrations. Application of the PASS model to a erse set of marine and freshwater environments indicates that (1) physical controls on nitrate removal in a bedform include the pore water flushing rate, residence time distribution, and relative rates of respiration and transport (as represented by the Damkohler number) (2) the biogeochemical pathway for nitrate removal is an environment-specific combination of direct denitrification of stream nitrate and coupled nitrification-denitrification of stream and/or sediment ammonium and (3) permeable sediments are almost always a net source of dissolved inorganic nitrogen. The PASS model also provides a mechanistic explanation for previously published empirical correlations showing denitrification velocity (N2 flux ided by nitrate concentration) declines as a power law of nitrate concentration in a stream (Mulholland et al. Nature, 2008, 452, 202-205).

A One‐Dimensional Model for Turbulent Mixing in the Benthic Biolayer of Stream and Coastal Sediments

Publisher: American Geophysical Union (AGU)

Date: 12-2020

DOI: 10.1029/2019WR026822

University Stormwater Management within Urban Environmental Regulatory Regimes: Barriers to Progressivity or Opportunities to Innovate?

Publisher: Springer Science and Business Media LLC

Date: 05-11-2020

DOI: 10.1007/S00267-020-01377-3

First-order contaminant removal in the hyporheic zone of streams: Physical insights from a simple analytical model

Publisher: American Chemical Society (ACS)

Date: 22-09-2014

DOI: 10.1021/ES501694K

Abstract: A simple analytical model is presented for the removal of stream-borne contaminants by hyporheic exchange across duned or rippled streambeds. The model assumes a steady-state balance between contaminant supply from the stream and first-order reaction in the sediment. Hyporheic exchange occurs by bed form pumping, in which water and contaminants flow into bed forms in high-pressure regions (downwelling zones) and out of bed forms in low-pressure regions (upwelling zones). Model-predicted contaminant concentrations are higher in downwelling zones than upwelling zones, reflecting the strong coupling that exists between transport and reaction in these systems. When flow-averaged, the concentration difference across upwelling and downwelling zones drives a net contaminant flux into the sediment bed proportional to the average downwelling velocity. The downwelling velocity is functionally equivalent to a mass transfer coefficient, and can be estimated from stream state variables including stream velocity, bed form geometry, and the hydraulic conductivity and porosity of the sediment. Increasing the mass transfer coefficient increases the fraction of streamwater cycling through the hyporheic zone (per unit length of stream) but also decreases the time contaminants undergo first-order reaction in the sediment. As a consequence, small changes in stream state variables can significantly alter the performance of hyporheic zone treatment systems.

Modeling the Effects of Turbulence on Hyporheic Exchange and Local‐to‐Global Nutrient Processing in Streams

Publisher: American Geophysical Union (AGU)

Date: 09-2018

DOI: 10.1029/2018WR023078

Predictive Power of Clean Bed Filtration Theory for Fecal Indicator Bacteria Removal in Stormwater Biofilters

Publisher: American Chemical Society (ACS)

Date: 08-05-2017

DOI: 10.1021/ACS.EST.7B00752

Abstract: Green infrastructure (also referred to as low impact development, or LID) has the potential to transform urban stormwater runoff from an environmental threat to a valuable water resource. In this paper we focus on the removal of fecal indicator bacteria (FIB, a pollutant responsible for runoff-associated inland and coastal beach closures) in stormwater biofilters (a common type of green infrastructure). Drawing on a combination of previously published and new laboratory studies of FIB removal in biofilters, we find that 66% of the variance in FIB removal rates can be explained by clean bed filtration theory (CBFT, 31%), antecedent dry period (14%), study effect (8%), biofilter age (7%), and the presence or absence of shrubs (6%). Our analysis suggests that, with the exception of shrubs, plants affect FIB removal indirectly by changing the infiltration rate, not directly by changing the FIB removal mechanisms or altering filtration rates in ways not already accounted for by CBFT. The analysis presented here represents a significant step forward in our understanding of how physicochemical theories (such as CBFT) can be melded with hydrology, engineering design, and ecology to improve the water quality benefits of green infrastructure.

Ambient groundwater flow diminishes nitrate processing in the hyporheic zone of streams

Publisher: American Geophysical Union (AGU)

Date: 05-2017

DOI: 10.1002/2016WR020048

Crossing Turbulent Boundaries: Interfacial Flux in Environmental Flows

Publisher: American Chemical Society (ACS)

Date: 09-08-2011

DOI: 10.1021/ES201778S

Abstract: Advances in the visualization and prediction of turbulence are shedding new light on mass transfer in the turbulent boundary layer. These discoveries have important implications for many topics in environmental science and engineering, from the transport of earth-warming CO2 across the sea-air interface, to nutrient processing and sediment erosion in rivers, lakes, and the ocean, to pollutant removal in water and wastewater treatment systems. In this article we outline current understanding of turbulent boundary layer flows, with particular focus on coherent turbulence and its impact on mass transport across the sediment-water interface in marine and freshwater systems.

Virginia Tech

Location: United States of America

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University Of California, Irvine

Location: United States of America

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Stanford University

Location: United States of America

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California Institute Of Technology

Location: United States of America

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Linkage Projects - Grant ID: LP110200821

Start Date: 07-2011

End Date: 06-2014

Amount: $225,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP120100718

Start Date: 08-2012

End Date: 12-2014

Amount: $440,900.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP130103619

Start Date: 01-2013

End Date: 12-2016

Amount: $430,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP210101595

Start Date: 04-2021

End Date: 03-2024

Amount: $671,476.00

Funder: Australian Research Council