How South West Water uses AIM to ensure a smarter future for drainage and wastewater planning.
Client:
South West Water
Location:
South West England
Consulting Partner:
ICS Consulting, AECOM, Stantec, supported by Probit
Asset Types:
Water Distribution and Trunk Mains, Drainage & Wastewater networks, above-ground plant and equipment, water resources.
AIM Version Used:
AIM 2.0-4.2
Key Outcome:
Successful delivery of regulator-compliant investment plans with advanced scenario modelling and long-term investment planning. SWW has been highlighted by OFGEM as high quality and fast-tracked in both PR14, PR19, and PR24.
South West Water (SWW) provides essential water and wastewater services to 1 million households and businesses, 2.2 million residents and 8 million tourists across Devon, Cornwall, and parts of Dorset and Somerset.
Its extensive asset base includes over 29 water treatment works, 645 wastewater treatment works, more than 1,000 combined sewer overflows, and a network of over 15,000 km of water mains and 14,000 km of sewers.
With 1,200 employees and an annual revenue of £500 million, SWW is responsible for maintaining safe drinking water, environmental compliance, and the protection of some of the UK’s best-known coastlines and bathing waters.
The challenge
Faced with the challenge of balancing asset performance, regulatory obligations and long-term environmental impact, SWW needed a strategic investment framework capable of handling complexity and scale.
Ofwat required that investment plans reflect customer values and account for future pressures such as climate change, urbanisation, and population growth, all while demonstrating best value for investment. Additionally, the UK Government introduced mandatory 25-year Drainage and Wastewater Management Plans (DWMPs).
SWW’s own DWMP covered 653 drainage catchments grouped into 22 regional areas, each requiring detailed modelling, scenario testing, and transparent planning.
Who worked on this project?
SWW partnered with their framework consulting partners, ICS, AECOM, Stantec, and Probit to deliver its regulatory investment plans through the deployment of AIM.
ICS led on consulting, bringing deep sector experience and managing the planning framework across multiple asset types. ICS consultants worked closely with SWW’s asset managers and policy leads to gather data, assess risk, and model interventions and costs.
Probit supported this work through expert configuration and technical guidance, helping to ensure AIM was fully tailored to meet SWW’s requirements and deadlines.
The partnership provided a robust foundation for one of the UK’s leading water companies.
How was AIM used?
SWW has been using AIM since 2013 (PR14) for above-ground assets at equipment level, and expanded its use across all water and waste networks in 2021, ready for PR24. This was then expanded to include Water Resources and DWMP catchment modelling, showing the platform’s flexibility. AIM was used to:
- Model individual assets including pipes and equipment, system reliability at treatment works and pumping stations and other above-ground complex assets.
- Generate risk maps that linked asset condition and failure to service impacts, customer preferences, and environmental risk.
- Run deterioration forecasts and model both traditional and nature-based intervention strategies (e.g. SuDS, wetlands, rain gardens).
- Optimise investment scenarios using budgetary and regulatory constraints to test hundreds of ‘what-if’ scenarios in hours, not days.
- Report findings through dashboards and configurable exports for internal teams and public stakeholders.
AIM also supported strategic planning for water resources and DWMP, from data collection and planning through to submission, providing a transparent, repeatable basis for long-term decision-making.
The results
The deployment of AIM gave SWW the ability to deliver a data driven and regulator-compliant investment plan fast tracked by OFGEM. Specific outcomes included:
- Confidence in the robustness and value-for-money of both draft and final plan submission.
- Rapid scenario testing, enabling investment plans to be modelled iteratively in hours rather than days.
- Improved targeting of investment to high-risk processes and assets, maximising impact and minimising disruption.
- A clear, defensible planning framework for future regulatory discussions and public engagement.
Dr Ben Ward
Drinking Water Asset Manager, South West Water
Technical insight
AIM supported SWW’s multi-objective investment planning by integrating multiple datasets, predictive deterioration models, and service and valuation frameworks, into a single unified risk map.
AIM’s risk nodes captured complex relationships between asset condition, system behaviour, and customer outcomes.
The optimisation engine handled constraints such as CSO and flood-risk targets, implementation timescales, and varying intervention types, providing scenario outputs in minutes.
AIM also enabled detailed lifecycle modelling and was adaptable enough to accommodate evolving priorities such as carbon, social, and environmental benefits: a growing area of focus for the sector.
What followed for SWW and AIM?
Following its successful ‘fast-tracked’ PR24 submission, SWW plan to expand AIM’s use to evaluate new and emerging investment questions, including climate change modelling and the cost-benefit of nature-based interventions and their environmental impact.
As AIM continues to evolve, it will support broader business planning activities across SWW, particularly in areas where complex trade-offs must be made between environmental goals, customer outcomes and operational budgets.
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