Effectiveness of BMP plans in different land covers, with random, targeted, and optimized allocation.

The ability of 5 Best Management Practice (BMP) allocation methods that consider 8 pre-selected BMPs, to control 4 Nonpoint Source (NPS) constituents in 4 watersheds with contrasting land covers, is investigated. The methods range from random selection of BMPs on randomly selected sites, to optimized selection of BMPs at optimized locations, and the land covers range from natural to ultra-urban. The optimization methods rely on Genetic Algorithms (GA), and a method that uses expert systems is also applied. Watershed hydrologic and water quality response models are developed, using the Soil Water Assessment Tool (SWAT), to compute baseline outputs from the 4 study watersheds without BMPs, and to obtain predicted reductions in NPS constituent outputs when BMPs are implemented in accordance with the 5 allocation plans. Methods used to represent BMPs in SWAT and to speed up optimization processes are also presented. Results indicate that the most computationally intensive methods produce the best results across landscape types. Results also show that opportunities exist for less intensive methods, particularly in less-built environments. For these, however, siting BMPs to hotspots remains an important requirement. The need to select the most appropriate BMP for each implementation site is observed to increase with the level of urbanization of the landscape. Results indicate that optimized selection of BMPs, sited at optimized locations, results in the highest-performing BMP allocation plans across landscape types. Also, the focus on hotspots has the advantage of resulting in BMP plans requiring involvement of fewer stakeholders than when BMPs are located in non-hotspot zones. This targeted hotspot approach could help reduce cost and increase efficiency of implementation.

Convergence in Perceptions of Ecosystem Services Supports Green Infrastructure Decision-making in a Semi-arid City.

Effective management of cities using ecosystem services from green infrastructure (GI) requires explicit consideration of the linkages between provision of services and ecosystem service demands (i.e., governance priorities). Identification of stakeholder knowledge and objectives in GI decision-making contexts with respect to ecosystem services may improve urban planning; yet this information is rarely explicit in local contexts and cases. We address this gap by surveying environmental stakeholders and practitioners to investigate how perceptions of ecosystem services influence GI practice in Tucson, AZ. Results indicate that the semi-arid environment and urban design led to prioritizations that focus on water sustainability and urban heat mitigation. We found strong agreement in environmental perceptions between different management sectors. We observed matches (as well as mismatches) between the ecosystem service priorities and important environmental issues. Ecosystem services prioritization revealed a unique classification of ecosystem services that reflects stakeholder priorities. Our findings suggest the study of ecosystem services supply and demand can inform local urban management. These findings from a semi-arid city further suggest that understanding stakeholder knowledge, perceptions, and priorities should be important for cities in other regions where GI is being implemented as an environmental solution to provide ecosystem services.

Sewage Systems Surveillance for SARS-CoV-2: Identification of Knowledge Gaps, Emerging Threats, and Future Research Needs.

The etiological agent for novel coronavirus (COVID-19, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), not only affects the human respiratory system, but also the gastrointestinal tract resulting in gastrointestinal manifestations. The high rate of asymptomatic infected individuals has challenged the estimation of infection spread based on patients' surveillance, and thus alternative approaches such as wastewater-based epidemiology (WBE) have been proposed. Accordingly, the number of publications on this topic has increased substantially. The present systematic review thus aimed at providing state-of-the-knowledge on the occurrence and existing methods for sampling procedures, detection/quantification of SARS-CoV-2 in sewage samples, as well as anticipating challenges and providing future research direction to improve the current scientific knowledge. Articles were collected from three scientific databases. Only studies reporting measurements of virus in stool, urine, and wastewater samples were included. Results showed that improving the scientific community's understanding in these avenues is essential if we are to develop appropriate policy and management tools to address this pandemic pointing particularly towards WBE as a new paradigm in public health. It was also evident that standardized protocols are needed to ensure reproducibility and comparability of outcomes. Areas that require the most improvements are sampling procedures, concentration/enrichment, detection, and quantification of virus in wastewater, as well as positive controls. Results also showed that selecting the most accurate population estimation method for WBE studies is still a challenge. While the number of people infected in an area could be approximately estimated based on quantities of virus found in wastewater, these estimates should be cross-checked by other sources of information to draw a more comprehensive conclusion. Finally, wastewater surveillance can be useful as an early warning tool, a management tool, and/or a way for investigating vaccination efficacy and spread of new variants.

Improved agricultural Water management in data-scarce semi-arid watersheds: Value of integrating remotely sensed leaf area index in hydrological modeling.

In watersheds located in semi-arid regions, vegetation dynamics, evapotranspiration (ET), and associated water and energy balances collectively play a major role in controlling hydrological regimes and crop yield. As such, it is challenging to predict the complex hydrological processes and biophysical dynamics. This challenge increases in areas with limited data availability. The key objective of this study was to evaluate the direct integration of remotely sensed Leaf Area Index (LAI) data into a hydrological model to improve streamflow, ET, and crop yield estimates. We also demonstrated how an improved model integrated with remotely sensed LAI data can inform water managers by predicting water productivity (WP) under different irrigation schemes. We took agricultural-dominated San Joaquin Watershed in California, United States, as our testbed and integrated the Moderate Resolution Imaging Spectroradiometer (MODIS) 500-m resolution 4-day total LAI data into the SWAT (Soil and Water Assessment Tool) model. Results showed that, compared to conventional SWAT model that relies on semi-empirical equations and user inputs for simulating biophysical processes, direct LAI integration into SWAT model (SWAT-LAI) notably captured the actual vegetation dynamics and improved ET and crop yield estimations. The WP simulated by the improved SWAT-LAI model for almond and grape yields varied within a range from 0.363 to 3.81 kg/m3 and 0.32 to 4.76 kg/m3 across different irrigation applications. The outcomes of this study showed that deficit irrigation application could be a viable option in water stressed regions, since it can save a substantial amount of irrigation water and maintain the higher water productivity required for both almond and grape yield production. This study shows an evidence of how remotely sensed data integrated into hydrological models can serve as a decision support tool by providing quantitative information on crop water use and crop production.

"Zooming" Our Way through Virtual Undergraduate Research Training: A Successful Redesign of the CONSERVE Summer Internship Program.

The COVID-19 pandemic has had an enormous impact on education globally, forcing the teaching community to think outside the box and create innovative educational plans to benefit students at home. Here, we narrate how the undergraduate, laboratory-based Summer Internship Program of our CONSERVE Center of Excellence, which focuses heavily on engaging women and underrepresented minorities in STEM programming, took a turn from an in-person research experience to a fully virtual one. We share our challenges and how we overcame them. Additionally, we provide a description of our virtual internship professional development curriculum, as well as the creative research projects that our seven interns were able to achieve in an 8-week virtual internship, including projects focused on the microbiological water quality of recycled irrigation water; social media promotion, enhancement and marketing of online educational resources focused on water, microbial contamination, and food crop irrigation; decision support systems for using recycled water in agricultural settings; and the effectiveness of zero-valent iron sand filtration in improving agricultural water quality, to name a few. Upon evaluating our internship program, we observed that more than 80% of our interns were either very satisfied or satisfied with the overall virtual internship experience. Through this experience, both the educators and the interns learned that although a virtual laboratory internship cannot completely replace in-person learning, it can still result in a very meaningful educational experience.

Potential Changes in Chemical Soil Quality Resulting from Graywater Recycling for Landscape Irrigation.

The effects of graywater irrigation on soil chemical properties, and the accumulation of surfactants and antimicrobials, were investigated at three households in Arizona, California, and Colorado over the duration of two to three years. No negative effects were observed, with respect to sodium and boron accumulation in soil, over the duration of this study. Graywater irrigation significantly increased organic matter and total inorganic nitrogen of the receiving soil (P < 0.05). Graywater loading rates and fertilizer application should be monitored to ensure that excessive amounts of nitrogen and phosphorus are not applied to the soil. Notable concentrations of antimicrobials were detected in surface soil samples. It is suggested that the effect of antimicrobials on soil microbial health, and the potential for formation of antibiotic-resistant genes, be further investigated. Surfactant concentration in soil samples substantially increased after graywater application, compared with baseline samples, and then remained fairly constant over time.

Leachability of chemical constituents in soil­plant systems irrigated with synthetic graywater.

Over recent years, reuse of graywater for irrigation has become increasingly widespread internationally. While this practice is rapidly growing, there remain unanswered questions with respect to impacts to environmental quality and human health. The objective of this research was to determine the leachability of graywater constituents after applied to soil through a set of controlled greenhouse experiments. Four plant species including bermudagrass, tall fescue, Meyer Lemon and Emerald Gaiety Euonymus were included in the study. Three replicate columns for each species were set up and irrigated either with synthetic graywater or potable water for a 17 month duration. Leachate quality was assessed for dissolved organic carbon, nitrate, ammonium, total phosphorous, boron, sodium adsorption ratio, conductivity, surfactants, and total dissolved solids. The same constituents and also organic matter were measured in soil samples collected at the end of experiments. Phosphorus did not leach through the 50 cm deep soil columns. Salts, including boron, showed potential to leach through graywater irrigated soil. A portion of the applied nitrogen was assimilated by plants, but leaching of nitrogen was still observed as documented by statistically higher nitrogen in leachate collected from graywater-irrigated columns compared to potable water-irrigated columns (P ≤ 0.05). A low percentage of surfactants added to columns leached through (7 ± 6% on average) and a mass balance on surfactant parent compounds showed that 92­96% of added surfactants were biodegraded.