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Water quality indices are employed by governments largely as a means of communicating the multifaceted nature of water quality and aquatic ecosystem health to the general public. Given the complexi...

Background: \ud The SARS-CoV-2 delta (B.1.617.2) variant was first detected in England in March, 2021. It has since rapidly become the predominant lineage, owing to high transmissibility. It is suspected that the delta variant is associated with more severe disease than the previously dominant alpha (B.1.1.7) variant. We aimed to characterise the severity of the delta variant compared with the alpha variant by determining the relative risk of hospital attendance outcomes.\ud \ud Methods: \ud This cohort study was done among all patients with COVID-19 in England between March 29 and May 23, 2021, who were identified as being infected with either the alpha or delta SARS-CoV-2 variant through whole-genome sequencing. Individual-level data on these patients were linked to routine health-care datasets on vaccination, emergency care attendance, hospital admission, and mortality (data from Public Health England's Second Generation Surveillance System and COVID-19-associated deaths dataset; the National Immunisation Management System; and NHS Digital Secondary Uses Services and Emergency Care Data Set). The risk for hospital admission and emergency care attendance were compared between patients with sequencing-confirmed delta and alpha variants for the whole cohort and by vaccination status subgroups. Stratified Cox regression was used to adjust for age, sex, ethnicity, deprivation, recent international travel, area of residence, calendar week, and vaccination status.\ud \ud Findings: \ud Individual-level data on 43 338 COVID-19-positive patients (8682 with the delta variant, 34 656 with the alpha variant; median age 31 years [IQR 17–43]) were included in our analysis. 196 (2·3%) patients with the delta variant versus 764 (2·2%) patients with the alpha variant were admitted to hospital within 14 days after the specimen was taken (adjusted hazard ratio [HR] 2·26 [95% CI 1·32–3·89]). 498 (5·7%) patients with the delta variant versus 1448 (4·2%) patients with the alpha variant were admitted to hospital or attended emergency care within 14 days (adjusted HR 1·45 [1·08–1·95]). Most patients were unvaccinated (32 078 [74·0%] across both groups). The HRs for vaccinated patients with the delta variant versus the alpha variant (adjusted HR for hospital admission 1·94 [95% CI 0·47–8·05] and for hospital admission or emergency care attendance 1·58 [0·69–3·61]) were similar to the HRs for unvaccinated patients (2·32 [1·29–4·16] and 1·43 [1·04–1·97]; p=0·82 for both) but the precision for the vaccinated subgroup was low.\ud \ud Interpretation: \ud This large national study found a higher hospital admission or emergency care attendance risk for patients with COVID-19 infected with the delta variant compared with the alpha variant. Results suggest that outbreaks of the delta variant in unvaccinated populations might lead to a greater burden on health-care services than the alpha variant.\ud \ud Funding: \ud Medical Research Council; UK Research and Innovation; Department of Health and Social Care; and National Institute for Health Research.

A comprehensive inventory of ecosystem services across the entire Great Lakes basin is currently lacking and is needed to make informed management decisions. A greater appreciation and understanding of ecosystem services, including both use and non-use services, may have avoided misguided resource management decisions in the past that have resulted in legacies inherited by future generations. Given the interest in ecosystem services and lack of a coherent approach to addressing this topic in the Great Lakes, a summit was convened involving 28 experts working on various aspects of ecosystem services in the Great Lakes. The invited attendees spanned a variety of social and natural sciences. Given the unique status of the Great Lakes as the world's largest collective repository of surface freshwater, and the numerous stressors threatening this valuable resource, timing was propitious to examine ecosystem services. Several themes and recommendations emerged from the summit. There was general consensus that 1) a comprehensive inventory of ecosystem services throughout the Great Lakes is a desirable goal but would require considerable resources; 2) more spatially and temporally intensive data are needed to overcome our data gaps, but the arrangement of data networks and observatories must be well-coordinated; 3) trade-offs must be considered as part of ecosystem services analyses; and 4) formation of a Great Lakes Institute for Ecosystem Services, to provide a hub for research, meetings, and training is desirable. Several challenges also emerged during the summit, which are discussed in the paper.

This analysis employs a stochastic cost frontier to estimate relationships between source water quality, production costs, and cost efficiency in Canadian municipal water treatment facilities. Data for the analysis are obtained primarily from a census of water providers that contains detailed information on operational costs, source water quality, and treatment technologies. Results show water quality, as measured by turbidity, is a significant determinant of production costs. The estimated elasticity for turbidity is 0.1, with a 95% confidence interval of 0.06 to 0.14. We find no significant differences in cost efficiency across regions, treatment technologies, output, or turbidity levels.

We evaluate the temporal stability of willingness-to-pay values obtained from two identical stated-preference surveys undertaken in 2004 and 2012. The surveys employ two discrete-choice elicitation formats to value reductions in two health endpoints related to tap water consumption, and are explicitly designed to make direct comparisons between formats. We find no significant differences in real willingness-to-pay between the two surveys for either format—a result that is robust to the structure of heterogeneity used to model respondent preferences. Findings lend support, at least within the context of tap water quality, to the temporal transfer of nonmarket benefits over extended time periods.

Many rural communities in Nepal experience considerable water stress during the dry season. Water storage systems (WSSs) have been proposed to supplement rain-fed irrigation and augment domestic water services in these communities. We evaluate household preferences for WSSs using a choice experiment and latent class modeling techniques. Results indicate the presence of three classes. The majority of households (≈92%) belong to two equally-sized classes, a relatively privileged group (i.e. wealthier, better educated, etc.) with strong preferences for supplemental irrigation and a less privileged group that is mainly interested in improved domestic water services. The remaining class’ preferences are dominated by the cost attribute and are consistent with households facing severe cash constraints. Estimated welfare effects reveal that WSSs disproportionately benefit the privileged, although this disparity is mitigated with the provision of domestic water. These findings highlight the potential welfare gains from WSS investments, but stress the need for multi-purpose water resource development and the potential for elite capture.

For community water providers, safeguarding source waters from contamination offers an additional barrier of protection and a potential means of avoiding in-plant treatment costs. Whether source water protection efforts are cost-effective relative to in-plant treatment requires hydrologic, geologic, and climatologic knowledge of source watersheds, as well as an understanding of how changes in source water quality affect treatment costs. Quantitative evidence on the latter relationship is limited. This study estimates separate hedonic cost functions for water systems that primarily use surface water sources and those that primarily use groundwater sources using a database of United States (US) Community Water Systems. Cost functions relate annual variable treatment cost to production, factor input prices, capital stock, and source water quality, as proxied by land use within various ex-ante defined contributing areas (i.e., surrounding land areas affecting source water quality). For surface water systems, a 1% increase in urban land relative to forestland is correlated with a 0.13% increase in annual variable treatment costs. In this analysis, the relationship between costs and agricultural land is not statistically significant. Conversely, for groundwater systems, a 1% increase in agricultural land relative to forestland is correlated with a 0.24% increase in costs, whereas in this analysis the relationship between costs and urban land is not statistically significant. The cost-effectiveness of forestland preservation, based on sample means, varies considerably with the size of the contributing area, with no clear indication as to whether preservation is more likely to be cost-effective for surface water or groundwater systems.

Green infrastructure (GI), practices consisting of using vegetation and soil to manage stormwater runoff (e.g., rain gardens, vegetated roofs, bioswales, etc.), has been adopted by cities across the world to help address aging water infrastructure, water quality, excess water quantity, and urban planning needs. Although GI’s contribution to stormwater control and management has been extensively studied, the economic value of its benefits is less known. In Omaha, NE, GI projects have been completed in several public parks. Using a repeat-sales model based on 2000–2018 housing data, we examined the effect of GI on the value of single-family homes within various buffer distances of parks where GI was installed. After controlling for changes associated with home deterioration and renovation, non-stationary location effects, and time-invariant characteristics, we did not find any statistically significant relationships between housing values and GI. This finding is consistent with the notion that homeowners place little value on modifications to existing greenspace, but may also stem from homeowners’ lack of familiarity with GI practices or data limitations.

‘What we need to do is inventory the different types of agricultural landscapes and bring to light the typical rural architecture, such as the acequias and desagues (irrigation supply canals and excess water drains). We need to find ways of conserving the landscape, including the flora and fauna as well as the role the agricultural landscape has played in the evolution of the surrounding area. Before we abandon the past (flood irrigation) for the contemporary (drip irrigation), we need a thorough analysis of the pros and cons of each system for the whole cultural landscape. The future may be one where the old and new learn to coexist, such as the hoe with the plow’ (Arellano, 2014, p. 204). WIREs Water 2015, 2:559–575. doi: 10.1002/wat2.1091 For further resources related to this article, please visit the WIREs website.

Devastating floods and ongoing droughts throughout the world highlight the infrastructure and management challenges facing water and wastewater utilities. While increasing variability in climate has been identified as the immediate culprit, the severity of events has been exacerbated by years of underinvestment in infrastructure improvements due to inadequate pricing of services. The American Water Works Association (2015) identifies a crucial step for decision-makers: identify clearly communities’ priorities with respect to water and wastewater management, both of which provide public or community-level goods and services. Using data from two separate choice experiments, collected in the same survey of Canadian households, the current paper estimates household willingness-to-pay (WTP) to reduce the likelihood of flood events and water service disruptions. Results from both choice experiments show a strong preference for policy scenarios that reduce these risks, although there is a substantial amount of heterogeneity. People living in the Prairie region, rural residents, and people living in areas with higher home values have a higher WTP. Although the results lend support to public infrastructure programs for addressing flood and water disruption risks, the degree to which these are preferred to private action is not clear.

In recent years mountain pine beetles (MPB), Dendroctonus ponderosae, along with several other bark beetle species, have severely damaged coniferous forests in the western United States (U.S.) and Canada (Morris and Walls, 2009). Colorado provides one example of a region that has been heavily affected. The Colorado State Forest Service estimates that 769,000 ha of Colorado's forests, of all jurisdictions, have been infested with MPB since the outbreak began in 1996 (Leatherman, 2009). An important consequence of this damage is declining utility (i.e. a reduction in the level of satisfaction derived from goods and services, both market and nonmarket) for residents of the wildland-urban interface (WUI). Specifically, beetle infestations lower utility by reducing the value of forest amenities and increasing the risk of wildfire. We use a hedonic pricing model to estimate willingness-to-pay (WTP) to prevent MPB damage in Grand County, Colorado. The hedonic model establishes a statistical relationship between property prices and various characteristics. In this case, the characteristic of interest is the number of trees killed by MPB infestations. A Geographic Information System (GIS) is used to determine the number of these trees within 0.1, 0.5, and 1.0 kilometer buffers of each property. Marginal implicit prices for MPB damage are calculated, after controlling for structural and spatial characteristics. Results indicate that property values decline by $648, $43, and $17 for every tree killed by MPB infestations within a 0.1, 0.5, and 1.0 km buffer, respectively.

Armed conflicts, which primarily occur in low- and middle-income countries, have profound consequences for the health of affected populations, among them a decrease in the utilization of maternal health care services. The quantitative relationship between armed conflict and maternal health care utilization has received limited attention in the public health literature. We evaluate this relationship for a particular type of health care service, antenatal care, in Nepal. Using count regression techniques, household survey data and sub-national conflict data, we find a negative correlation between the number of antenatal care visits and incidents of conflict-related violence within a respondent's village development committee. Specifically, we find that under high-intensity conflict conditions women receive between 0.3 and 1.5 fewer antenatal care check-ups. These findings imply that maternal health care utilization is partially determined by characteristics of the social environment (e.g. political instability) and suggest health care providers need to revise maternal health strategies in conflict-affected areas. Strategies may include decentralization of services, maintaining neutrality among factions, strengthening community-based health services and developing mobile clinics.

Residential rebate programs for low-flow water devices have become increasingly popular as a means of reducing urban water demand. Although program specifics vary, low-flow rebates are available in most U.S. metropolitan areas, as well as in many smaller municipalities. Despite their popularity, few statistical analyses have been conducted regarding the effects of low-flow rebates on household water use. In this paper, we consider the effects of rebates from the Albuquerque Bernalillo County Water Utility Authority (ABCWUA). Using panel regression techniques with a database of rebate recipients, we estimate the marginal effects of various low-flow devices on household water demand. Results indicate a negative correlation between household water use and the presence of most low-flow devices, after controlling for water price and weather conditions. Low-flow toilets have the greatest impact on water use, while low-flow washing machines, dishwashers, showerheads, and xeriscape have smaller but significant effects. In contrast, air conditioning systems, hot water recirculators, and rain barrels have no significant impact on water use. We also test for possible rebound effects (i.e. whether low-flow appliances become less-effective over time due to poor rates of retention or behavioral changes) and compare the cost effectiveness of each rebate using levelised-costs. We find no evidence of rebound effects and substantial variation in levelised-costs, with low-flow showerheads being the most cost-effective device under the current ABCWUA rebate program. The latter result suggests that water providers can improve the efficiency of rebate programs by targeting the most cost-effective devices.