Environmental modelling

The UK water industry faces a complex combination of environmental, operational and regulatory challenges

These challenges require a detailed understanding of how water systems interact and behave. Environmental modelling enables water companies, regulators and stakeholders to investigate many of these challenges and identify effective, evidence-based solutions.

One of the most significant challenges is the impact of storm overflows and wastewater discharges on rivers, estuaries and coastal waters. Environmental models can assess spill frequency, pollutant loads, ecological impacts and compliance with environmental standards, helping organisations understand where improvements are required and which interventions will deliver the greatest benefit.

Population growth, urban development and ageing infrastructure place increasing pressure on wastewater networks, creating risks of sewer flooding, capacity constraints and deterioration in receiving water quality. Modelling helps identify future pressures and evaluate options to increase resilience while supporting sustainable growth.

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Addressing environmental challenges

Environmental modelling is also used to investigate catchment-scale issues, including nutrient pollution, diffuse agricultural runoff, phosphorus enrichment, pesticide contamination and bathing water quality. By assessing the cumulative effects of multiple pollution sources, organisations can better understand the causes of environmental deterioration and target measures where they will be most effective.

Climate change introduces further uncertainty through increased rainfall intensity, droughts, extreme weather and changing river flows. Environmental models allow future scenarios to be tested, helping water companies understand potential risks and develop adaptive strategies.

By providing insight into the interactions between wastewater systems, rivers, groundwater and catchment processes, environmental modelling helps address some of the most pressing environmental challenges facing the UK water industry today.

Expertise in water quality, hydrology, catchment science and environmental economics

WRc combines specialist expertise in water quality, hydrology, catchment science and environmental economics with industry-leading modelling tools to assess the impacts of wastewater discharges, storm overflows, diffuse pollution and land-use change on the aquatic environment. Through baseline monitoring, water quality assessments and advanced data analytics, WRc develops the evidence needed to understand environmental risks, prioritise interventions and demonstrate compliance with evolving regulatory requirements.

At a catchment scale, WRc’s SIMPOL Integrated Catchment Modelling (ICM) platform enables long-term simulation of the entire water cycle, helping organisations evaluate interactions between water resources, customer demand, wastewater systems and receiving waters. River quality assessments using SIMCAT-SAGIS support source apportionment studies and help identify the contributions of different pollution sources to waterbody failures.

For storm overflow and Urban Pollution Management (UPM) assessments, WRc provides specialist expertise and tools such as UPM-RAT, enabling rapid and defensible evaluation of ecological risks associated with intermittent discharges. These tools support compliance assessments, spill performance analysis, climate change scenario testing and the development of effective improvement programmes.

WRc has extensive experience supporting Storm Overflow Assessment Framework (SOAF) assessments, using tools including UPM-RAT and SIMPOL to assess the environmental impact of intermittent discharges. WRc’s expertise includes assessing storm overflow spill performance, impacts on receiving water quality and compliance against relevant environmental standards. This provides water companies with a robust evidence base to understand environmental risks and identify where improvements may be required.

WRc also supports Water Industry National Environment Programme (WINEP) investment planning, helping water companies translate environmental evidence and modelling outputs into targeted investment programmes. By combining environmental modelling, risk assessment and cost-benefit analysis, WRc helps identify and prioritise interventions that provide the greatest environmental benefit and support the delivery of regulatory and environmental objectives.

WRc also supports catchment management initiatives through phosphorus compliance studies, pesticide and metaldehyde risk assessments, strategic monitoring programmes, cost-benefit analysis and solution optimisation. By integrating scientific evidence, modelling and economic assessment, WRc helps clients identify cost-effective interventions that deliver measurable improvements in water quality, biodiversity and environmental resilience while supporting long-term regulatory and investment objectives.

Key benefits of WRc environmental modelling

Evidence-based decision making: Robust monitoring, modelling and analytics provide a scientifically defensible basis for investment planning, regulatory compliance and environmental improvement programmes.
Optimised and cost-effective solutions: Integrated modelling and cost-benefit assessments help identify the most effective combination of catchment interventions, nature-based solutions and infrastructure investments.
Regulatory compliance and investment planning: WRc’s experience in SOAF and WINEP helps water companies translate environmental modelling and assessment outputs into practical investment decisions, supporting regulatory requirements and the delivery of environmental improvements.
Improved environmental outcomes and resilience: Advanced tools support assessment of storm overflows, water quality, climate change impacts and pollution risks, helping organisations protect rivers, strengthen resilience and deliver sustainable catchment management.

An approach underpinned by decades of applied research, regulatory support and proven modelling tools

Evidence includes long-term work with the Environment Agency, successful phosphorus compliance and catchment management programmes, nationally recognised tools such as SIMPOL ICM, and UPM-RAT, and robust methodologies combining monitoring, modelling, risk assessment, cost-benefit analysis and stakeholder engagement to deliver evidence-based environmental outcomes.

Environment Agency