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This case study uses the concept of ecosystem services and specifically payments for ecosystem services, alongside five experiences from the Westcountry Rivers Trust (WRT), which celebrates its 30th anniversary in 2024, to demonstrate the need for integrated catchment management (ICM). It highlights the multifaceted benefits that ecosystems provide to human well-being, the challenges faced in managing these often-siloed services and the role of ICM in preserving and enhancing multiple ecosystem services, focusing on the water-related drivers of flooding, drought, water quality and aquatic biodiversity. Through WRT projects this case study highlights practical applications and successes in managing ecosystem services at the catchment level and what considerations are needed for future integration and delivery of multi-benefit solutions. This paper is derived in part from the interviews and workshops undertaken as part of the Atlantic Area Interreg funded Triple C project (EAPA_772/2018), as well as contributions from the Horizon funded, InnWater project (Horizon EUROPE No. 101036683 and UKRI No. 10066637) and the OFWAT-funded, mainstreaming Nature-based Solutions.

Abstract Catchment floods are more challenging due to intensive urbanization and climate change. Enlightened by the Low Impact Development (LID), China initiated the Sponge City Program (SCP) to transform Urban Flood Management (UFM) to be more environmentally friendly in 2013. The China National Government (CNG) has subsidized municipal SCP facilities to enhance urban flood resilience while delivering multiple co‐benefits for urban ecosystems and social well‐being. Recent floods at Schleiden (Germany), Arizona State (USA), and Zhengzhou (China) in 2021 reflected the necessity of Catchment Flood Management (CFM) to cover the whole catchment scale. The SCP, designed to handle small‐scale urban pluvial floods, has brought concerns when facing larger‐scale fluvial floods after the Zhengzhou 2021 flood. Indeed, catchment‐scale Natural Flood Management (NFM) can manage fluvial floods while improving flood adaptations sustainably from upstream to downstream reaches. This research develops a new framework named the Sponge Catchment Management Plan (SCMP), including structural and Nonstructural elements. On the structural side, the SCMP framework integrates NFM with the SCP and Grey Engineering (GE) for reducing the fluvial flood discharge peaks in the whole‐catchment scale. On the nonstructural side, the SCMP encourages collaborative governance, revising technical standards, and improving “bottom‐up” participation. This research used Semi‐Structured Interviews (SSIs) and a Focus Group Approach (FGA) to explore 62 professional and Nonprofessional stakeholders’ perspectives on the SCMP framework. Some professional respondents did not know much about the NFM and were worried about the effectiveness of this practice. But most interviewees supported the SCMP pilot work and shared the co‐benefits from the NFM. This case study at the SW China, Guiyang, could be a lesson to encourage other Chinese cities further implement SCP to improve catchment‐scale flood resilience.

In the UK, most large reservoirs constructed for public water supply are in upland areas. Many are situated in catchments characterised by organic-rich soils, including peatlands. Although these soils naturally leach large amounts of dissolved organic matter (DOM) to water, the widespread degradation of upland peat in the UK is believed to have exacerbated rates of DOM loss. High and rising DOM concentrations in these regions raise treatment challenges for the water industry. In the UK, water companies are increasingly considering whether upland-catchment peat restoration measures can slow down or even reverse rising source water DOM concentrations and, thus, reduce the need for more costly and complex engineering solutions. There remains considerable uncertainty around the effectiveness of such measures, and a comprehensive overview of the research in this area remains lacking. Here, we review the peer-reviewed evidence of the effectiveness of four catchment management options in controlling DOM release from peat soils: ditch blocking, revegetation, reducing forest cover and cessation of managed burning. Results of plot-scale investigations into the effects of ditch blocking on DOM leaching are currently largely equivocal, while there is a paucity of information regarding impacts at spatial scales of more direct relevance to water managers. There is some, although limited, evidence that the terrestrial vegetation type may influence DOM concentrations and treatability. The presence of plantation forestry on peat soils is generally associated with elevated DOM concentrations, although reducing forest cover appears to have little short-term benefit, and associated disturbance may even increase concentrations further. Catchment management measures have rarely been monitored with downstream water quality as the focus. To mitigate the uncertainty surrounding restoration effects on DOM, measures should be undertaken on a site-specific basis, where the scale, effect size and duration of the intervention are considered in relation to subsequent biogeochemical processing that occurs in the reservoir, the treatment capacity of the water treatment works and future projected DOM trends.