Solve environmental problems holistically
Researchers at the University of Newcastle and the James Hutton Institute are exploring how the engineering of catchment systems can be a holistic approach to solving certain environmental problems.
Capture Systems Engineering (CSE) is a holistic approach to improving the environment, involving direct intervention in the landscape initiated and carried out by engineers, scientists and practitioners in close collaboration with stakeholders such as as farmers, landowners and people living and working in watersheds.
Watersheds are areas of land that contribute to the flow of water to a common point. This is the ideal unit to operate since a watershed is naturally defined by how water moves through the landscape – any rain that falls in a particular watershed ends up in the same river that goes to the sea.
In a recent review published in WIREs Water, researchers at Newcastle University and the James Hutton Institute, Drs Caspar Hewett, Mark Wilkinson, Jennine Jonczyk and Paul Quinn provide contrasting examples of successful ESCs.
For example, the village of Belford in Northumberland, England had major flooding problems and in order to alleviate them, CSE interventions were introduced: removal of tight bends, selected walls and a walkway in the village ; clean and renovate the sewer system; and many features of the surrounding rural landscape that target the upstream flow entering the village. In the seven years since the project was completed, Belford has not been inundated.
In Rajasthan, India, drought had dried up most of the rivers, driving much of the population from the land. The local population mobilized to create 15,000 traditional leakage dams to retain the flow of floods, collect rainwater and allow it to infiltrate deeper groundwater. As a result, many rivers now flow all year round and the population has returned to the land.
CSE involves a variety of interventions of different sizes targeted at specific locations, each with a specific objective such as improving water quality or reducing flood risk. It is holistic in two senses: first, in that the entire catchment system, which generally includes rural and urban areas, is taken into account in deciding why, where, when and how to intervene; and second, it simultaneously targets several problems such as floods, drought, water pollution and soil erosion.
Many CSE interventions mimic natural processes and are often described as nature-based solutions. They can play an important role in providing ecosystem services, from improving carbon accumulation to reducing pollution. Examples include afforestation, peatland restoration, reconnection of floodplains, and ‘soft-engineered’ interventions, such as strategically placed wooded dams in small canals that slow flow and temporarily store water during flows. students. These are used alongside traditional engineering elements such as dams, embankments, flood gates and temporary flood defenses, which provide additional protection to assets and urban areas.
The CSE provides a framework for identifying and prioritizing failures in a watershed and provides site specific metrics to deliver multiple benefits such as reduction of rapid runoff, erosion, and pollution. Many interventions can fit seamlessly into the rural landscape using locations such as areas adjacent to rivers and streams, small-scale natural canals, and agricultural ditches. However, ESC is not simply driven by technical considerations as its holistic nature requires addressing cross-cutting issues ranging from land use planning and policy development (e.g. forestry, ‘agriculture, asset management) to the management of ecosystem services (eg tourism, nature protection, water management). Thus, the involvement of stakeholders in the planning and implementation of the CSE is essential. To make this successful, researchers, practitioners, and policy makers must work with all stakeholders within a watershed, especially landowners, to ensure effective program implementation.
âThe CSE can be a powerful framework for solving environmental problems,â said Hewett, âWe just have to be bold and remember to think of the catchment system as a whole, otherwise there is a danger that an intervention that provides a benefit in one location actually causes problems elsewhere in the watershed.
âTo get it right, we need to identify the processes that need mitigation, determine what we want the watershed to deliver, and commit to intervening across the system (including urban areas) – that’s why l ‘involvement of people working and living in watersheds is so important; especially those who manage local water and can provide and maintain the required metering. It’s a new way to look at established problems and get the most out of proven traditional engineering and more experimental nature-based solutions – it’s the way to go.
Written by: Caspar Hewett
Research article available from CJM Hewett, et al. SON Water, 2020, doi.org/10.1002/wat2.1417