Protecting rivers by integrating supply-wastewater infrastructure planning and coordinating operational decisions

Abstract

Placing water quality in rivers at the centre of water infrastructure planning and management is an important objective. In response there has been a range of 'whole system' analyses. Few studies, however, consider both abstraction (water removed from rivers) and discharge (water returned) to inform the future planning of water systems. In this work we present a systems approach to analysing future water planning options where system development prioritises the water quality of the receiving river. We provide a theoretical demonstration by integrating water supply and wastewater infrastructure, and downstream river water quality, on an open-source, stylised, systems model for London, UK, at a citywide scale. We show that models which consider either supply or wastewater separately will underestimate impacts of effluent on the water quality, in some cases by amounts that would require £1 billion worth of infrastructure equivalent to mitigate. We highlight the utility of the systems approach in evaluating integrated water infrastructure planning using both socio-economic and environmental indicators. Through this approach we find unintended impacts from planning options on downstream river quality; including benefits from water demand management and rainwater harvesting, and costs from wastewater reuse. Finally, we present a novel management planning option between supply and wastewater, which we refer to as Abstraction-Effluent Dilution (AED), that is, to reduce river abstractions during high precipitation events to dilute untreated sewer spills. The AED option is found to provide up to £200 million worth of equivalent infrastructure in river quality improvements and has minimal impact on the reliability of water supply while requiring only a change in operational decision making. This proof-of-concept study highlights that seeing our water systems differently with this holistic approach could fundamentally change the way we think about future water infrastructure planning so that it works both for people and the environment.

An Urban Planning Sustainability Framework: Systems Approach to Blue Green Urban Design

“…Although for now it only includes a static evaluation of the urban development project based on a 'before-after' evaluation, new models that include a more dynamic approach should be considered in the next stages of the work. These novel models should have the capacity to link with: a) dynamic population trends; b) Life Cycle Assessment (LCA) methods applied to the urban scale in spatial planning (Bidstrup et al, 2015;Mirabella et al, 2018); c) Blue Green Infrastructure (BGI) cost-benefit analysis in the long term of the urban development; and, d) water infrastructure tools, such as CityWat (Dobson and Mijic, 2020). The exploration of new urban models will be part of the improved integrated evaluation toolkit of UPSUF.…”

Selecting Indicators and Optimizing Decision Rules for Long‐Term Water Resources Planning

“…The DECIPHeR flow series is available at https://doi.org/10.5523/bris.2pkv9ox-gfzvts235zrui7xz00g. Monthly water demand profile has been published by Dobson and Mijic (2020) and accessed via https://zenodo.org/record/3764678#.Xs0JNmhKhPY. Demand projections at company level have been published by the Environment Agency ( 2019), accessed at https://data.gov.uk/dataset/fb38a40c-ebc1-4e6e-912c-bb47a76f6149/revised-draft-water-resources-management-plan-2019-supply-demand-dataat-company-level-2020-21-to-2044-45#licence-info.…”

The Resilience of Inter-basin Transfers to Severe Droughts With Changing Spatial Characteristics

“…2pkv9oxgfzvts235zrui7xz00g. Monthly water demand profile has been published by Dobson and Mijic (2020) and accessed via https://zenodo.org/record/3764678#.Xs0JNmhKhPY. Demand projections at company level have been published by the Environment Agency (2019b), accessed at https://data.gov.uk/ dataset/fb38a40c-ebc1-4e6e-912c-bb47a76f6149/revised-draftwater-resources-management-plan-2019-supply-demand-dataat-company-level-2020-21-to-2044-45#licence-info.…”