Sensors used for wastewater flow measurements need to be robust and are, consequently, expensive pieces of hardware that must be maintained regularly to function correctly in the hazardous environment of sewers. Remote sensing can remedy these issues, as the lack of direct contact between sensor and sewage reduces the hardware demands and need for maintenance. This paper utilizes off-the-shelf cameras and machine learning algorithms to estimate the discharge in open sewer channels. We use convolutional neural networks to extract the water level and surface velocity from camera images directly, without the need for artificial markers in the sewage stream. Under optimal conditions, our method estimates the water level with an accuracy of ±2.48% and the surface velocity with an accuracy of ±2.08% in a laboratory setting—a performance comparable to other state-of-the-art solutions (e.g., in situ measurements).

https://www.mdpi.com/2073-4441/14/3/424

This Handbook provides a comprehensive overview of how water, energy and food are interconnected, comprising a coherent system: the nexus. It considers the interlinkages between natural resources, governance processes seeking coherence among water, energy and food policies, and the adoption of transdisciplinary approaches in the field.

With contributions covering a broad range of disciplinary perspectives and cross-cutting themes, the Handbook has a well-balanced mix of conceptual chapters and empirical studies. It includes a state-of-the-art analysis of the concepts and experiences in implementing the nexus in different policy environments, providing examples of successful integrated decision-making across the domains of water, energy and food. Offering a global perspective on water, energy and food security, the Handbook contains insights into achieving both national development goals and the Sustainable Development Goals. Chapters further highlight how to understand the concepts of the nexus in practice, impacts of the nexus in governance, policy and business, and methods and tools to strengthen the nexus.

Interdisciplinary and thorough, this Handbook will be critical reading for environmental management, public policy and human geography scholars. It will also be a useful tool for policymakers looking for successful examples of policy coherence towards an integrated management of water, energy and food resources.