Centralized water infrastructure has, over the last century, brought safe and reliable drinking water to much of the world. But climate change, combined with aging and underfunded infrastructure, is increasingly testing the limits of—and reversing gains made by—this approach. To address these growing strains and gaps, we must assess and advance alternatives to centralized water provision and sanitation. The water literature is rife with examples of systems that are neither centralized nor networked, yet meet water needs of local communities in important ways, including: informal and hybrid water systems, decentralized water provision, community‐based water management, small drinking water systems, point‐of‐use treatment, small‐scale water vendors, and packaged water. Our work builds on these literatures by proposing a convergence approach that can integrate and explore the benefits and challenges of modular, adaptive, and decentralized (“MAD”) water provision and sanitation, often foregrounding important advances in engineering technology. We further provide frameworks to evaluate justice, economic feasibility, governance, human health, and environmental sustainability as key parameters of MAD water system performance.This article is categorized under: Engineering Water > Water, Health, and Sanitation Human Water > Water Governance Engineering Water > Sustainable Engineering of Water

Water resources management is a nontrivial process requiring a holistic understanding of the factors driving the dynamics of human‐water systems. Policy‐induced or autonomous behavioral changes in human systems may affect water and land management, which may affect water systems and feedback to human systems, further impacting water and land management. Currently, hydro‐economic models lack the ability to describe such dynamics either because they do not account for the multifactor/multioutput nature of these systems and/or are not designed to operate at a river basin scale. This paper presents a flexible and replicable methodological framework for integrating a microeconomic multifactor/multioutput Positive Multi‐Attribute Utility Programming (PMAUP) model with an eco‐hydrologic model, the Soil and Water Assessment Tool (SWAT). The connection between the models occurs in a sequential modular approach through a common spatial unit, the “hydrologic‐economic representative units” (HERUs), derived from the boundaries of decision‐making entities and hydrologic responsive units. The resulting SWAT‐PMAUP model aims to provide the means for exploring the dynamics between the behavior of socio‐economic agents and their connection with the water system through water and land management. The integrated model is illustrated by simulating the impacts of irrigation restriction policies on the Río Mundo subbasin in south‐eastern Spain. The results suggest that agents' adaptation strategies in response to the irrigation restrictions have broad economic impacts and subsequent consequences on surface and groundwater hydrology. We suggest that the integrated modeling framework can be a valuable tool to support decision‐making in water resources management across a wide range of scales.

The Great Lakes basin hosts the world's most abundant surface fresh water reserve. Historically an industrial and natural resource powerhouse, the region has suffered economic stagnation in recent decades. Meanwhile, growing water resource scarcity around the world is creating pressure on water‐intensive human activities. This situation creates the potential for the Great Lakes region to sustainably utilize its relative water wealth for economic benefit. We combine economic production and trade datasets with water consumption data and models of surface water depletion in the region. We find that, on average, the current economy does not create significant impacts on surface waters, but there is some risk that unregulated large water uses can create environmental flow impacts if they are developed in the wrong locations. Water uses drawing on deep groundwater or the Great Lakes themselves are unlikely to create a significant depletion, and discharge of groundwater withdrawals to surface waters offsets most surface water depletion. This relative abundance of surface water means that science‐based management of large water uses to avoid accidentally creating “hotspots” is likely to be successful in avoiding future impacts, even if water use is significantly increased. Commercial water uses are the most productive, with thermoelectric, mining, and agricultural water uses in the lowest tier of water productivity. Surprisingly for such a water‐abundant economy, the region is a net importer of water‐derived goods and services. This, combined with the abundance of surface water, suggests that the region's water‐based economy has room to grow in the 21st century.