Managing stormwater in South African neighbourhoods: When engineers and scientists need social science skills to get their jobs done

Stormwater harvesting via managed aquifer recharge in retrofitted infrastructure has been posited as a method for resource augmentation in Cape Town. However, the existing guidelines on stormwater retrofits are technically inclined, occidental, and generally misaligned with the realities and socio-economic contexts of developing nations like South Africa. Water and urban practitioners from developing nations cannot just 'copy and paste' existing guidelines as different socio-economic dimensions and colonial histories typically hinder 'traditional' approaches. This paper assesses how a transdisciplinary team navigated these realities in a case study of a retrofitted pond in Mitchells Plain, Cape Town. A decolonial thinking framework was applied for reflection and thematic content analysis. The framework was used to unpack how the team encountered, addressed, and learned from the challenges during the retrofit process. The research team found that the retrofit process within a context of under-resourced South African communities can be viewed as developmental work with a strong emphasis on continuous community engagement. Thus, it is suggested that in the South African context, water practitioners should consider, at the fore, interaction with local communities, including awareness of racialised histories, to ensure projects are successfully implemented and completed.

Effects of Temperature and Water Types on the Decay of Coronavirus: A Review

The analysis of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) gene copy numbers in wastewater samples can provide quantitative information on Coronavirus Disease-19 (COVID-19) cases within a sewer catchment. However, many wastewater-based epidemiology (WBE) studies have neglected virus decay during the wastewater transportation process in sewers while back-calculating COVID-19 prevalence. Among various sewer condition parameters, wastewater temperature and dilution by fresh/saltwater infiltration may result in a significant change to the virus decay, in terms of both infectivity and Ribonucleic Acid (RNA). This paper reviewed the literature to identify and discuss the effects of temperature and water types (i.e., wastewater, freshwater, and seawater) on coronavirus decay based on the decay rate constants that were collected from published papers. To evaluate the importance of virus decay, a sensitivity analysis was then conducted with decay rates of SARS-CoV-2 RNA based on a WBE back-calculation equation. Finally, the decay rates of coronavirus in wastewater were also compared with those of other viruses to further understand the difference among virus species. The decay of SARS-CoV-2 RNA was found to be less impacted by temperature variation than viable coronaviruses. Nevertheless, WBE back-calculation was still sensitive to the RNA decay rates increased by warm wastewater (i.e., over 26 °C), which could lead to a two-times higher relative variance in estimated COVID-19 prevalence, considering the wastewater temperature variation between 4 and 37 °C in a sewer catchment with a 12-h hydraulic retention time. Comparatively, the sensitivity of the WBE estimation to the enveloped SARS-CoV-2 was greater than nonenveloped enteric viruses, which were less easily degradable in wastewater. In addition, wastewater dilution by stormwater inflow and accompanied cold weather might alleviate the decay of coronavirus infectivity, thus increasing the potential risk of COVID-19 transmission through wastewater. Overall, this paper aims to better understand the impact of in-sewer processes on coronavirus decay and its potential implications for WBE. The outcome could quantitatively inform WBE and improve awareness of the increased risk of COVID-19 infection via wastewater during heavy rainfall events. Given the identified scarcity of data available for coronavirus decay in salt water or with chemical additions, future research on the fate of SARS-CoV-2 subjected to chemical dosing for sewer or wastewater treatment plant operations is recommended. © 2023 by the authors.

Land use and COVID-19 lockdowns influence debris composition and abundance in stormwater drains.

Stormwater drains act as a pathway for anthropogenic debris from land to sea, particularly in urbanised estuaries where impervious surfaces expedite the process. Debris type and abundance in stormwater drains may vary due to land use and human activity, and knowledge of this variation is necessary to manage the growing threat of debris. Surveys of stormwater debris can inform targeted reduction and remediation efforts by intercepting and identifying pollutants near their source. We surveyed replicate stormwater gross pollutant traps across four land use zones (city centre, shopping centre, transportation hub, industrial precinct) before and during COVID-19 measures to assess the effects of changing human activities. Gross pollutant traps were installed in 120 drains in Greater Melbourne, Australia, and citizen scientists trained by Tangaroa Blue Foundation weighed and classified debris at 6-week intervals between October 2019 and October 2020. Four survey cycles were conducted before lockdowns were implemented, then another four during lockdowns. COVID-19 lockdowns and patterns of debris type and abundance across land use revealed how changes in human activity might impact the flow of debris. Cigarette butts were the most abundant macro debris (>5 mm) item in every survey cycle, regardless of lockdowns. Industrial land use zones had the lowest macro debris counts but contained over 90 % of the micro debris (1-5 mm). The amount of total macro debris decreased during lockdowns, however the most abundant and problematic debris items such as cigarettes and single-use plastics did not decrease as much as might be expected from the concomitant reductions in human activity. Occupational health and safety items, such as masks and gloves, increased (144 %) during COVID-19 lockdowns. Micro debris counts did not change in industrial zones during lockdowns, suggesting that workplace interventions may be necessary to reduce this debris leakage. Tracing the pathway of debris from source to sea can inform reduction and long-term management strategies.

Finding space for nature in cities: the considerable potential of redundant car parking

Nature-based solutions (NBS) are recognised as a means to address challenges such as heatwaves, flooding and biodiversity loss. Delivering these benefits at scale will require large areas of scarce urban land to be converted into green space. Here we show an approach by which cities can make substantial progress towards their sustainability targets using NBS, by converting redundant street parking into biodiverse green space. We demonstrate that up to half of street parking in our case study municipality (The City of Melbourne) could be accommodated in garages within 200 m, freeing up large areas for greening. Our modelling projects significant benefits in terms of tree canopy over, stormwater and ecological connectivity. These would represent strong progress towards a number of the city’s ambitious NBS targets. As many cities allocate extensive areas to both street parking and off-street garages, this approach to freeing up space for nature in cities is widely applicable.

Experimental Research on the Treatment of Stormwater Contaminated by Disinfectants Using Recycled Materials-Hemp Fiber and Ceramzite.

Pollution caused by the use of disinfectants in public spaces is a relatively new form of environmental contamination. During the COVID-19 pandemic of 2020-2021, early research showed a sevenfold increase in the use of disinfectants to clean outdoor spaces and a corresponding increase in environmental pollution. Typically, after entering stormwater systems, disinfectants are carried to surface waters (e.g., rivers, seas and lakes) where they react with various elements to form harmful compounds. In the absence of data, it is not possible to determine accurate levels of pollution according to the latest scientific information. Our enquiry demonstrates that stormwater pollution indicators (pH, conductivity, turbidity and color intensity) change depending on the amounts of disinfectants present. Laboratory tests were conducted using hemp fiber and ceramzite, in which filtered stormwater samples contaminated with different amounts of disinfectants showed decreases in the amounts of active chlorine from 2.93 ppm to 1.0 ppm. Changes in pH levels, conductivity, turbidity and color intensity were monitored before and after filtration; pH indicators changed slightly (from 7.81 to 7.85), turbidity changes varied in the range of 0.070-0.145 NTU and the highest value of color intensity (1.932 AV) was obtained when 50 mL of disinfectant was added to the investigated sample water. This article presents the results of our research into the impact of disinfectants on stormwater. Further investigation is needed in order to determine the impacts of chemical substances on our water ecosystem.

Intra-scale Design and Benefit Assessment of Green Stormwater Infrastructures

By considering the effects of climate change in urban areas, the paper investigates the benefits of environmental design strategies as green stormwater infrastructures. The environmental dimension of spatial planning sits alongside and interfaces with other sustainability challenges in the urban environment. Moreover, the advent of the COVID-19 pandemic focused their crucial importance in the reorganization of places that are “safe” because they allow movement through cities with minimal risk of contagion, providing an adequate opportunity for safe socialization. The research studied the design of green streets equipped with GSI devices in a portion of the town of Aversa (CE), to mitigate flooding, improve the microclimatic conditions and the quality of public spaces. The work was carried out with the support of software simulation of the microclimatic and physical behavior of urban areas (ENVI-Met) and evaluation of the benefits of ecosystem services (iTree Eco), performing in a cyclic way the phases of Analysis, Design and Verification. The approach allowed to refine the results obtained by selecting the most appropriate solutions for the project. The computer simulation of microclimatic conditions is a useful tool for the environmental assessment of limited urban ecosystems, where it would be particularly costly to install a series of small stations to detect the local weather conditions. The holistic approach to urban regeneration planning and project leads to a constant assessment of the increase of the ecosystem services resulting from the solutions chosen in the cyclical process of research through design. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Collaboration is the key to innovation

Collaboration is defined as the act of working with someone to produce or create something. When it comes to the water industry, Technology Approval Groups (TAG) are innovation forums that can be found around the world. They were first launched in the United Kingdom in 2005 TAG accelerates the market update of "step-change" technologies by engaging the industry during the pre-commercial stages of development and by leveraging the power of collective leading end-users to collaborate around shared interests and priorities. TAG is a low-risk option for utilities looking to collect information not commonly found at conferences or other public forums. Even though such groups are not new, the concept is new to most New England utilities. The U.S. program comprises more than 75 utilities and is growing exponentially. The author's experience with these forums provides a unique perspective to the region's needs and the key drivers for those needs. Adaptation is the new normal since the beginning of the Covid-19 pandemic. New England utilities are focused on asset management, distribution and collection system maintenance, stormwater, and reservoir management. This paper will describe how the TAG model rooted in collaboration can assist utilities along with water and wastewater professionals throughout the region to think outside the box and learn about qualified solutions becoming available with each passing day. © 2021 New England Water Environment Association. All rights reserved.

GeoHealth Perspectives on Integrated, Coordinated, Open, Networked (ICON) Science

GeoHealth research both characterizes and predicts problems at the nexus of earth and human systems like climate change, pollution, and natural hazards. While GeoHealth excels in the area of integrated science, there is a need to improve coordinated and networked efforts to produce open science to enable environmental justice. There is a need to resource and empower frontline populations that are disproportionately marginalized by environmental injustice (i.e., the unequal protection from environmental harms and lack of access and meaningful engagement in decision making for a healthy environment;EPA, 2022, https://www.epa.gov/environmentaljustice). GeoHealth practice has the opportunity to advance environmental justice or the “fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income” with respect to how research and collaboration of GeoHealth professionals supports the “development, implementation, and enforcement of environmental laws, regulations, and policies” that produce equal protection from environmental and health hazards and access to the decision making for a health environment (EPA, 2022, https://www.epa.gov/environmentaljustice). Here we highlight barriers and opportunities to apply an equity‐centered ICON framework to the field of GeoHealth to advance environmental justice and health equity.

A Mobile Laboratory Enables Fecal Pollution Source Tracking in Catchments Using Onsite qPCR Assays

Onsite molecular diagnostics can revolutionize fecal pollution source tracking. We aimed to validate a method for onsite qPCR assays with a miniature speaker-sized Q qPCR instrument and other portable equipment items. We showed that marker genes for total bacteria (16S) and E. coli (rodA) in 100 mL of river water measured with this method agreed within ±0.3 log10 units with results obtained when using conventional laboratory equipment items. We then deployed the portable method in a mobile laboratory (‘lab in a van’) and quantified HF183 marker genes for human host associated Bacteroides in river water within 3 h of sampling. We also used the mobile laboratory to investigate urban river water and effluents from two storm drains and a retention pond and collected comprehensive microbial and physicochemical water quality data. We found significantly higher HF183 gene levels in the older storm drain compared to the river water (6.03 ± 0.04 vs. 4.23 ± 0.03 log10 gene copies per 100 mL), and a principal component analysis revealed that storm drain effluent retention in a pond beneficially altered water characteristics, making them more like those of the receiving river. In conclusion, onsite qPCR assays can be performed with portable equipment items to quickly test water.

Assessment of Palm Jumeirah Island’s Construction Effects on the Surrounding Water Quality and Surface Temperatures during 2001–2020

Climate change stressors like rising and warmer seas, increased storms and droughts, and acidifying oceans are rapidly threatening coastal zones, which are the world’s most densely inhabited places. This research assesses the effects of Palm Jumeirah Island (PJI) construction on its surrounding water quality and temperature, using Landsat-7 and 8 spectral and thermal bands for the years 2001, 2014, 2016, 2019, and 2020. To aid in this goal, the changes in water spectral reflectance was observed and interpreted, based on previous research and measurements, to discover the correlation between water quality and its spectral reflectance. Then, the sea surface temperature (SST) was calculated for the years under review and changes in water temperature were evaluated. Finally, the Green Normalized Difference Vegetation Index (GNDVI) and the Normalized Difference Turbidity Index (NDTI) were calculated to estimate water chlorophyll levels and water turbidity, respectively, and changes were observed and interpreted for the time period under review. The present study showed that the PJI construction not only increased the water reflectance in the 0.5–0.8 µm of wavelength, which can be considered to be the increase of suspended sediments and chlorophyll but the water temperature also increased by 7.5 °C during the 19 years. In addition, a gradual increase in the values of GNDVI (by 0.097–0.129) and NDTI (by 0.118~0.172) were observed. A drop in chlorophyll and suspended sediment spectral reflectance and GNDVI and NDTI values were also observed in 2020 compared to 2019 which can be attributed to the 63 to 82% decrease in tourists in Dubai in 2020 as a result of the COVID-19 pandemic. This study aims to draw attention to environmental issues by clarifying the effect of creating artificial islands in the sea and our analysis and results are a suitable reference for specialized hydrological and environmental studies based on spectral information and distance measurements, as presented in this paper.

Barriers to the Adoption of Urban Living Labs for NBS Implementation: A Systemic Perspective

Urban Living Labs (ULLs) are widely believed to provide a safe environment for experimentation, co-creation and evaluation of innovations in real-life settings. A growing number of cities have been adopting ULLs to co-create and test Nature-Based Solutions (NBS). However, many of these cities have been facing major barriers in trying to adopt the ULL approach for implementing NBS. In this study, we seek to identify these barriers and provide a systemic understanding. Barriers are identified by means of workshops and interviews. Subsequently, interpretive structural modelling serves to identify the interdependencies among the barriers, resulting in a structural model of barriers in adopting ULLs for NBS. Our results show that political and institutional barriers are significantly limiting the adoption of ULLs. Moreover, knowledge brokers and other intermediaries, as well as cross-sectoral collaboration, play a key role in getting ULLs adopted. The findings from this study can help cities to develop strategies that overcome the main barriers for ULL adoption in the context of nature-based solutions.