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.

Multi-bioinspired hierarchical integrated hydrogel for passive fog harvesting and solar-driven seawater desalination.

In recent years, with the outbreak and epidemic of the novel coronavirus in the world, how to obtain clean water from the limited resources has become an urgent issue of concern to all mankind. Atmospheric water harvesting technology and solar-driven interfacial evaporation technology have shown great potential in seeking clean and sustainable water resources. Here, inspired by a variety of organisms in nature, a multi-functional hydrogel matrix composed of polyvinyl alcohol (PVA), sodium alginate (SA) cross-linked by borax as well as doped with zeolitic imidazolate framework material 67 (ZIF-67) and graphene owning macro/micro/nano hierarchical structure has successfully fabricated for producing clean water. The hydrogel not only can reach the average water harvesting ratio up to 22.44 g g-1 under the condition of fog flow after 5 h, but also be capable of desorbing the harvested water with water release efficiency of 1.67 kg m-2 h-1 under 1 sun. In addition to excellent performance in passive fog harvesting, the evaporation rate over 1.89 kg m-2 h-1 is attained under 1 sun on natural seawater during long-term. This hydrogel indicates its potential in producing clean water resources in multiple scenarios in different dry or wet states, and which holds great promise for flexible electronic materials and sustainable sewage or wastewater treatment applications.

Tillandsia-Inspired Composite Materials for Atmospheric Water Harvesting

Atmospheric water harvesting (AWH) is a potentially promising small-scale approach to alleviate the water crisis in arid or semiarid regions. Inspired by the asymmetric structure of tillandsia leaves, a plant species native to semiarid regions, we report the development of a bioinspired composite (BiC) to draw moisture for AWH applications. With the advent of the post-COVID era, the nonwoven materials in used masks are discarded, landfilled, or incinerated along with the masks as medical waste, and the negative impact on the environment is inevitable. The nonwoven sheet has porosity, softness, and certain mechanical strength. We innovatively developed BiCs, immobilizing hygroscopic salt with a nonwoven mask for fast vapor liquefaction and using a polymer network to store water. The resulting BiC material manages to achieve a high-water adsorption capacity of 1.24 g g-1 under a low-moderate humidity environment and a high-water release ratio of ca. 90% without the use of photothermal materials, while maintaining high structural integrity in cyclic testing. © 2023 American Chemical Society.

Optimized Ridge–Furrow Ratio to Decrease Greenhouse Gas Emissions and Increase Winter Wheat Yield in Dry Semi-Humid Areas

The plastic-mulched ridge–furrow rainwater harvesting (RF) system has been widely adopted worldwide due to its visible economic benefits. However, few and inconclusive studies have focused on greenhouse gas (GHG) emissions. In addition, it is still unknown whether different coverage ratios under RF have an impact on greenhouse gas emissions. Here, we evaluate the effects of various coverage ratios on the soil hydrothermal characteristics, global warming potential (GWP), greenhouse gas intensity (GHGI), and yield productivity in dry semi-humid areas. A control (FP, conventional flat planting without mulching) and three different ridge–furrow ratios (40:40 (RF40), 40:60 (RF60), and 40:80 (RF80)) were tested in 2017–2019. Compared with FP, RF increased the soil temperature and promoted soil moisture in the furrows during the vegetative growth period. However, the soil temperature of the furrows slightly increased with furrow width, whereas the soil moisture obviously decreased under the three RF practices. In a wet year (2017–2018), FP significantly increased the winter wheat yield (43.6%) compared with RF, while the opposite was the case in a normal year (2018–2019). Among the three RF treatments, RF40 and RF80 significantly increased the yield by 13.9% and 17.2%, respectively, compared with RF60. Compared with FP, all of the RF treatments increased the flux of N2O and CO2 emissions but reduced CH4 absorption. Compared with FP, RF with ridge–furrow ratios of 40:40 cm, 40:60 cm, and 40:80 cm increased the GWP by 99.6%, 53.4%, and 31.3%, respectively, and increased the GHGI by 55.8%, 45.3%, and 0.7%, respectively. Therefore, conventional flat planting in wet years and a ridge–furrow ratio of 40:71 cm in normal years can reduce GHG emissions, sustaining crop productivity, and promote the sustainable development of agriculture and the environment. [ FROM AUTHOR] Copyright of Agronomy is the property of MDPI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Water usage pattern in the aftermath of COVID-19

Maintenance of good health and avoiding a viral infection is the prime focus for an individual during COVID-19 pandemic. Water being a universal solvent is used widely to clean the disinfectants in public places and individual household level. This study was designed to find any change in the water consumption pattern among the households after the emergence of COVID-19. To study this, a questionnaire was prepared and sent to the respondents through Google Forms. Collected data was analysed using suitable statistical methods and the results indicate that there was a significant change in the consumption pattern of drinking water from cold to hot (37.98%) among the respondents and also with respect to the total water usage. As the disease is communicable in nature, more water is needed to clean and disinfect the surface areas, washing hands etc. This eventually has a significant burden on the water resources in countries where water is already deficient, like India. It is recommended to adopt water conservation practices/technologies at the individual level by means of rain water harvesting techniques or use of efficient water aerator taps etc. to reduce water consumption.

Geospatial Analysis of Hydrometeorological Dynamics for Managing Socio-economie and COVID-19 Threats in the Ossiomo Watershed, Nigeria

The geographical occurrence and diffusion of the current COVID-19 pandemic is partly a function of the awareness, socio-economic dynamics, mobility, and health management practices in place. In Nigeria, the first confirmed case of the COVID-19 pandemic was proclaimed on February 27, 2020, in which an Italian citizen was tested positive for the virus in Lagos. Ossiomo watershed in Edo State, Nigeria, is mainly a rural region with limited healthcare access and abundant rains and surface water flowing in different drainage networks. The highly contagious and pathogenic COVID-19 disease, requires effective management of available water resources for sustainable health development. This is because one of the recommendations for preventing COVID-19 is washing hands with soap using running water. In most rural Africa, including Ossiomo, healthcare facilities are inadequate and no sustainable pipe-borne water except rain harvesting for survival. Using Inverse Distance Weighted (IDW) Geographic Information System (GIS) interpolation technique, the rainfall map produced (derived from a 31-year collated geo-coded hydrometeorological data - rainfall and discharge, covering the Ossiomo watershed) shows that rainfall decreases northward with minimum monthly precipitation of 18.8mm in January and to the south with a mean maximum rainfall of 339.0mm in July. NCDC records on Covid-19 were used to create Choropleth maps that revealed very low confirmed cases and relatively moderate-high deaths, though considered relatively low when compared to global statistics. The Pearson Product Moment Correlation Coefficient (PPMCC) further indicates a strong correlation between rainfall and drainage discharge with r=0.717. With sustainable socio-economic activities and adequate water supply, coupled with effective COVID-19 management practices, the pandemic may not linger in the study area.

Resilience of Interdependent Urban Water Systems

[...]the enhancement of resilience of urban water management solutions is an emerging topic for water research and the water industry. [...]it is important to understand how urban water systems behave when they fail and to ensure that they can recover quickly. For the resilience of such smart systems, the authors considered an integrated resilience assessment consisting of the performance of the combined sewer overflows, rain-water harvesting efficiency, and irrigation volume. [...]the smart systems also rely on the quality of digital parameters, such as the reliability of the communication technology and the quality of weather forecasts, for control strategies. [...]in this study, these disturbances of usually optimal working conditions were implemented in an integrated resilience analysis of a large-scale implementation of smart rain-water harvesting.