Global water research and monitoring typically focus on the household's “main source of drinking‐water.” Use of multiple water sources to meet daily household needs has been noted in many developing countries but rarely quantified or reported in detail. We gathered self‐reported data using a cross‐sectional survey of 405 households in eight communities of the Republic of the Marshall Islands (RMI) and five Solomon Islands (SI) communities. Over 90% of households used multiple sources, with differences in sources and uses between wet and dry seasons. Most RMI households had large rainwater tanks and rationed stored rainwater for drinking throughout the dry season, whereas most SI households collected rainwater in small pots, precluding storage across seasons. Use of a source for cooking was strongly positively correlated with use for drinking, whereas use for cooking was negatively correlated or uncorrelated with nonconsumptive uses (e.g., bathing). Dry season water uses implied greater risk of water‐borne disease, with fewer (frequently zero) handwashing sources reported and more unimproved sources consumed. Use of multiple sources is fundamental to household water management and feasible to monitor using electronic survey tools. We contend that recognizing multiple water sources can greatly improve understanding of household‐level and community‐level climate change resilience, that use of multiple sources confounds health impact studies of water interventions, and that incorporating multiple sources into water supply interventions can yield heretofore‐unrealized benefits. We propose that failure to consider multiple sources undermines the design and effectiveness of global water monitoring, data interpretation, implementation, policy, and research.

Pacific Island Countries (PICs) lag behind global trends in water, sanitation and hygiene (WaSH) development. We conducted a systematic search of all English language papers (published before February 2015) about WaSH in PICs to evaluate the state of the peer-reviewed literature and explore thematic findings. A total of 121 papers met the criteria for full-text review following an initial search result of more than 6,000 papers. Two reviewers independently assessed the quality and relevance of each article and consolidated their findings according to four emergent themes: public health, environment, emergency response and interventions, and management and governance. Findings indicate a knowledge gap in evidence-guided WaSH management strategies that advocate for human health while concurrently protecting and preserving drinking water resources. Extreme weather events threaten the quantity and quality of limited freshwater resources, and cultural factors that are unique to PICs present challenges to hygiene and sanitation. This review highlights the strengths and weaknesses of the peer-reviewed literature on WaSH in PICs, addresses spatial and temporal publication trends, and suggests areas in need of further research to help PICs meet development goals.

Pacific Island Countries (PICs) lag behind global trends in water, sanitation and hygiene (WaSH) development. We conducted a systematic search of all English language papers (published before February 2015) about WaSH in PICs to evaluate the state of the peer-reviewed literature and explore thematic findings. A total of 121 papers met the criteria for full-text review following an initial search result of more than 6,000 papers. Two reviewers independently assessed the quality and relevance of each article and consolidated their findings according to four emergent themes: public health, environment, emergency response and interventions, and management and governance. Findings indicate a knowledge gap in evidence-guided WaSH management strategies that advocate for human health while concurrently protecting and preserving drinking water resources. Extreme weather events threaten the quantity and quality of limited freshwater resources, and cultural factors that are unique to PICs present challenges to hygiene and sanitation. This review highlights the strengths and weaknesses of the peer-reviewed literature on WaSH in PICs, addresses spatial and temporal publication trends, and suggests areas in need of further research to help PICs meet development goals.

Design rainfall time series are a critical input for urban flood modeling and require depth-duration-frequency curves along with a design temporal pattern. The association between rainfall depth and duration, which depicts the inherent structure of rainfall patterns, plays an important role in flood-causing potential; this association can be revealed through a bivariate rainfall frequency analysis to obtain the depth-duration-frequency curves. Unlike earlier approaches that use either parametric or nonparametric models, the present study proposes a new semiparametric model approach, which can evaluate all possible combinations of the parametric-nonparametric marginals without restrictions. A comparison between the copula-based bivariate frequency analysis and the generalized least-squares regression shows the former to be better in performance. The first three best-fit models-Gaussian kernel, triangle kernel, and Burr type XII combined with the generalized Pareto distribution-yield consistently similar results, indicating the robustness of the approach. Realistic design rainfall temporal pattern could also be derived from the observed set of temporal patterns using their skew, kurtosis, and bimodality measure to quantify the maximum flood-causing potential and also to generate the design rainfall time series. The proposed framework has been demonstrated for a severely flood-prone coastal megacity, Mumbai, in India. (C) 2015 American Society of Civil Engineers.

The investigation of multiple sources in household water management is considered overly complicated and time consuming using paper and pen interviewing (PAPI). We assess the advantages of computer-assisted personal interviewing (CAPI) in Pacific Island Countries (PICs). We adapted an existing PAPI survey on multiple water sources and expanded it to incorporate location of water use and the impacts of extreme weather events using SurveyCTO on Android tablets. We then compared the efficiency and accuracy of data collection using the PAPI version (n = 44) with the CAPI version (n = 291), including interview duration, error rate and trends in interview duration with enumerator experience. CAPI surveys facilitated high-quality data collection and were an average of 15.2 min faster than PAPI. CAPI survey duration decreased by 0.55% per survey delivered (p < 0.0001), whilst embedded skip patterns and answer lists lowered data entry error rates, relative to PAPI (p < 0.0001). Large-scale household surveys commonly used in global monitoring and evaluation do not differentiate multiple water sources and uses. CAPI equips water researchers with a quick and reliable tool to address these knowledge gaps and advance our understanding of development research priorities.

Safe drinking water is critical to human health and development. In rural sub-Saharan Africa, most improved water sources are boreholes with handpumps; studies suggest that up to one third of these handpumps are nonfunctional at any given time. This work presents findings from a secondary analysis of cross-sectional data from 1509 water sources in 570 communities in the rural Greater Afram Plains (GAP) region of Ghana; one of the largest studies of its kind. 79.4% of enumerated water sources were functional when visited; in multivariable regressions, functionality depended on source age, management, tariff collection, the number of other sources in the community, and the district. A Bayesian network (BN) model developed using the same data set found strong dependencies of functionality on implementer, pump type, management, and the availability of tools, with synergistic effects from management determinants on functionality, increasing the likelihood of a source being functional from a baseline of 72% to more than 97% with optimal management and available tools. We suggest that functionality may be a dynamic equilibrium between regular breakdowns and repairs, with management a key determinant of repair rate. Management variables may interact synergistically in ways better captured by BN analysis than by logistic regressions. These qualitative findings may prove generalizable beyond the study area, and may offer new approaches to understanding and increasing handpump functionality and safe water access.

Coastal urban cities frequently face multiple hazards, including potentially disastrous extreme events. To combat this, vulnerability assessment is essential to developing an effective mitigation strategy. This study proposes a framework to assess the vulnerability of any densely populated urban area to disasters by considering both the population and the assets that are at risk. A set of indicators is also proposed to assess the vulnerability of social and socioeconomic systems, infrastructure, critical facilities, and adaptive capacity. The components of vulnerability were evaluated individually, using an accessible open source geographic information system at a fine 1-km grid scale, providing an insight into the spatial variability of the vulnerability. The optimal weight for individual indicators was assigned using data envelopment analysis to minimize subjective judgment and establish confidence in the results obtained. To decorrelate and reduce the dimensionality of the multivariate data, principal component analysis was performed. The proposed methodology was demonstrated on the twenty-four wards of Mumbai under the jurisdiction of the Municipal Corporation of Greater Mumbai and showed the mideastern part of Mumbai as the most vulnerable—mainly due to the increase in population and the marginal workers' ratio. A reduction in social vulnerability has been observed, however, across the city through improvement in the literacy rate and the main workers' ratio.

The Pacific region presents some of the lowest water and sanitation coverage figures globally, with some countries showing stagnating or even declining access to improved water and sanitation. In addition, Pacific Island Countries (PICs) are among the most vulnerable countries on the globe to extreme and variable climatic events and sea-level rise caused by climate change. By exploring the state of water and sanitation coverage in PICs and projected climatic variations, we add to the growing case for conserving water, sanitation and hygiene (WASH) interventions within a holistic integrated water resource management (IWRM) framework. PICs face unique challenges of increasing variability in rainfall (leading to drought and flooding), increasing temperatures, and likely higher than average sea-level rise, all of which impact on freshwater security. Add to this geographic and economic isolation, and limited human and physical resources, and the challenge of WASH provision increases dramatically. In this setting, there is a stronger case than ever for adopting a holistic systems understanding, as promoted by IWRM frameworks, to WASH interventions so that they consider past and current challenges as well as future scenarios.

Many rivers in Australia and elsewhere around the world are flow stressed. There is now considerable activity to restore crucial components of the natural flow regime of such rivers—known as environmental flows, but methods underpinning the decision-making often lack rigour and transparency. The restoration of environmental flow regimes is usually determined using historic flow data, available expertise, sometimes ad-hoc compromise between conflicting and spatio-temporally variable water needs, and then implemented through special environmental allocations or water sharing plans. However, ecological flow requirements are poorly integrated into the decision-making process. This paper reports an eco-hydrological Bayesian network model developed to assist in risk assessment and decision-making on improving the flow conditions for Australian Grayling (Prototroctes maraena) in the Yarra River in south-eastern Australia. The Yarra environmental flow model was adapted from previous work on Australian Grayling in the Latrobe River system, and contained the same ecological model as for the Latrobe River, but with a new hydrological sub-model developed specifically for the Yarra River. The model was used to assess the relative ecological benefits (to Australian Grayling) of restoring specific components of the natural flow regime, in particular autumn freshes and spring freshes.

ABSTRACTThis paper reports the development and application of two Bayesian Network models to assist decision making on the environmental flows required to maintain the ecological health of the Daly River (Northern Territory, Australia). Currently, the Daly River is unregulated, with only a small volume of water extracted annually for agriculture. However, there is considerable pressure for further agricultural development in the catchment, particularly with demand for extra water extraction during the dry season (May–November).The abundances of two fish species—barramundi (Lates calcarifer) and sooty grunter (Hephaestus fuliginosus)—were chosen as the ecological endpoints for the models, which linked dry season flows to key aspects of the biology of each species. Where available, data were used to define flow–fish habitat relationships, but most of the relationships were defined by expert opinion because of a lack of quantified ecological knowledge.Recent field data on fish abundances were used to validate the models and gave prediction errors of 20–30%. The barramundi model indicated that the adult sub‐population was key to overall fish abundance, with this sub‐population particularly impacted by the timing of abstraction (early vs. late dry season). The sooty grunter model indicated that the juvenile sub‐population dominated the overall abundance and that this was primarily due to the amount of hydraulically suitable riffle habitat. If current extraction entitlements were fully utilized, the models showed there would be significant impacts on the populations of these two fish species, with the probability of unacceptable abundances increasing to 43% from 25% for sooty grunter and from 36% for barramundi under natural conditions. Copyright © 2010 John Wiley & Sons, Ltd.

In developed countries a social learning approach has been shown to support Integrated Water Resources Management (IWRM) by fostering stakeholders' understanding of system complexity, recognition of mutual dependence, appreciation of others' perspectives, and development of the capacity to work together and to create mutual trust. Much less is known about social learning's potential in less developed small island states, particularly postconflict island states, where integration must navigate prescriptive management, limited resources, widely differing world views, a history of adversarial relationships, and unsuccessful attempts at government-community collaboration. This paper analyzes the transformative aspects of a social learning experience that occurred during research facilitating participatory integrated catchment management in the Pacific. The study elicited community and expert knowledge to create systems understanding to generate and analyze complex scenarios for integrated catchment risk assessment in the Kongulai catchment, Solomon Islands. Separate sequenced and then combined discussions led to facilitated exploration of others' subjective assessment of catchment risks and management options. Issues of transparency, trust, accountability, and mutual responsibility were explored in carefully created discursive spaces, assisted by the immediacy of personal contact and the absence of complex bureaucratic structures. Despite historical difficulties, through the use of bridging individuals, participants were generally able to transcend the constraints of their individual knowledge cultures, expand awareness and appreciation of the complexity of human-environment systems for IWRM, and envisage new opportunities for productively working together in integrated catchment management.

The procedures involved in model development may be set out as a ten step process, beginning with defining the purpose of the model and ending with evaluation of the appropriateness and utility of the completed model. This process, recently outlined by Jakeman et al. [Jakeman, A.J., Letcher, R.A., Norton, J.P., 2006. Ten iterative steps in development and evaluation of environmental models. Environmental Modelling and Software 21, 602-614], is often iterative as model development is a continuous process that refines and improves the intended capacity of the model. Here, the ten steps of model development are critiqued and applied using a process-based biogeochemical model of aquatic systems, with examples from two case studies: a model of phytoplankton succession and nutrient concentrations in the Swan-Canning Estuary (Western Australia) and a model of sediment and nutrient transport and transformation in the Fitzroy Estuary and Keppel Bay (Queensland). Crown Copyright (C) 2007 Published by Elsevier Ltd. All rights reserved.

The Swan River estuary, Western Australia, has undergone substantial hydrological modifications since pre-European settlement. Land clearing has increased discharge from some major tributaries roughly 5-fold, while weirs and reservoirs for water supply have mitigated this increase and reduced the duration of discharge to the estuary. Nutrient loads have increased disproportionately with flow and are now approximately 20-times higher than pre-European levels. We explore the individual and collective impacts of these hydrological changes on the Swan River estuary using a coupled hydrodynamic-ecological numerical model. The simulation results indicate that despite increased hydraulic flushing and reduced residence times, increases in nutrient loads are the dominant perturbation, producing increases in the incidence and peak biomass of blooms of both estuarine and freshwater phytoplankton. Changes in salinity associated with altered seasonal freshwater discharge have a limited impact on phytoplankton dynamics.

A trial to artificially destratify part of the water column of the Swan-Canning Estuary took place over four weeks in 1997. Destratification was attempted with bubble plumes created by pumping compressed air through a porous pipe near the bed at a location in the upper estuary. The purpose of the trial was to determine whether the resultant bubble 'curtain' could mix the water column, thereby altering the extent of upstream and downstream mixing and the vertical structures of salinity, temperature, dissolved oxygen and turbidity. The destratification trial was monitored using three techniques: vertical profiles taken on several days at selected stations along the estuary, fine scale profiles in the vicinity of the bubble curtain on one day, and continuous water column profiles taken I km upstream of the curtain. The seasonal upstream propagation of brackish water underneath a residual freshwater discharge was affected by the magnitude of freshwater discharge and tidal elevations. Superimposed upon diurnal and semi-diurnal tides were non-tidal water level changes induced mostly by variations in barometric pressure. These caused large changes in the salt wedge position. Destratification by the bubble curtain was compromised by these large oscillations, which limited the exposure of the salt wedge region to the mixing action of the bubble curtain. Complete vertical mixing of the water column was observed up to 30 m either side of the curtain on 30 October. Disruptions to the density stratification were not evident beyond 350 m of the curtain. In the immediate vicinity (similar to 30 m) of the curtain, deficits of dissolved oxygen in bottom waters were generally reduced or obliterated and a naturally turbid plume of water near the bottom of the estuary was mixed through the water column. The effects of the bubble curtain on dissolved oxygen, turbidity and temperature were, however, similar to those for salinity, with mixing confined to around 30 m from the curtain and no effect observed further than 350 m away. The upper Swan River estuary, although relatively narrow and strongly vertically stratified, is unsuited to destratification using bubble plumes. Cycling of spring and neap tides and non-tidal water level changes, together with freshwater inflows to the estuary, strongly limit the longitudinal extent of mixing by bubble curtains. Copyright (C) 2001 John Wiley & Sons, Ltd.

Hydraulic residence times and transitions between freshwater and brackish water regulate not only biomass, but also phytoplankton succession in estuaries. In the Swan River estuary in Western Australia, marine diatoms and slow-growing dinoflagellates dominate the phytoplankton assemblage during periods of low flow, when water in the upper and lower basins of the estuary approaches marine salinity. Relatively fast-growing freshwater diatoms and chlorophytes are associated with higher flow rates generated by freshwater runoff in winter and spring. Modifications to the estuary and its catchment over the last century, particularly dredging at the mouth of the Swan River estuary, have increased salinities in both basins of the estuary, so that dinoflagellates and marine diatoms dominate the phytoplankton assemblage for most of the year.