SIMPOL ICM: Integrated Catchment Modelling for Water Quality

Industry-leading environmental modelling package designed for fast, long term simulation of the whole water catchment to inform water quality.

Dr Karen Murrell is our expert in SIMPOL ICM

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Whole water cycle simulation

SIMPOL ICM is a flexible, integrated, environmental modelling package designed for fast, long term simulation of the whole water cycle. It represents water resources, water treatment and distribution, driven by customer demand, and integrates with the urban wastewater systems and river catchments to produce receiving water flow and quality results in response to rainfall and temperature variations.

Our industry-leading consultancy services inform environmental regulators, water companies and industrial customers. We support water quality planning and permitting in surface waters, estuary, coastal and marine environments.

Comprehensive rainfall inputs

Representing the watershed catchment with the same rainfall means SIMPOL ICM provides appropriate dilution and eliminates the need to estimate the receiving water flow and quality.

Faster, continuous stimulation

Without the fine resolution detail of InfoWorks or MIKE11, multi-year continuous simulations become fast and practical.

Compatible with existing models

Parameters and calibration results can be provided by existing sewer and river network models (e.g. InfoWorks and MIKE11).

Find your perfect combined solution

SIMPOL allows optimal combinations of strategies to be identified, such as different catchment management, network and treatment options.

Don't just take our word for it

  • Informing compliance
  • Safeguarding growth
  • Saving time

WRc were appointed to investigate the impact of flood alleviation options in a town using a SIMPOL model. These included additional capacity via a new trunk sewer; closure of a problematic overflow, and installation of a CSO. 

This provided The Environment Agency with evidence required to be confident that the new CSO would not cause deterioration in receiving water quality in the nearby river.

WRc modelled a catchment to support future wastewater planning and investigation of population growth, urban creep and climate change. 

This study successfully demonstrated how SIMPOL ICM performs against the water utility client's previous modelling capabilities to simulate load treatment and flow conveyance in the catchment. This allowed evaluation of a range of interventions to enable continued levels of service.

WRc used SIMPOL ICM to investigate pressures in two catchments, such that spatial and temporal variations, interactions, and consequences were represented and understood to support the development of a Water Resource Management Plan. 

The 100 year simulations investigating issues such as turbidity in raw water intake and water quality compliance in receiving waters each took less than 8 hours to run.

Key model features


• Integration of river and sewer systems
• Handles multiple wastewater discharges
• Accounts for drain-down times and follow-on storms
• Rainfall driven (which can be spatially represented)
• Sewer quality processes (e.g. dilution, build up and wash off, diurnal effects)
• Calibrated to InfoWorks results
• Handles correction factors for water quality standards
• Regulator approved

Agriculture and diffuse pollution

• Represents both agricultural and urban diffuse pollution
• Different land use types and wash-off loadings
• Fertiliser and pesticide rates and application periods

Resources and customer demand

• Models raw resources, reservoirs, treatment and distribution
• Identifies pinch points for customer demand exceeding supply
• Dynamic simulation of property types and occupancy rates
• Produces multi-decade projections (e.g., climate change)

Truly integrated catchment management

Watch our SIMPOL ICM expert, Dr. Karen Murrell, explain how WRc's comprehensive package benefits our clients in the water industry.

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Created by potrace 1.16, written by Peter Selinger 2001-2019
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Dr Karen Murrell

Principal Consultant (Catchment Management)

Karen's expertise lies in river impact assessment and integrated catchment management studies involving river hydraulic and quality modelling (both model application and development). This includes determining impacts of weather derived rural and urban pollution on receiving water quality. She also has extensive experience in consenting policy and application. Karen regularly works to apply deterministic and stochastic river quality models (such as SIMPOL ICM and SIMCAT/SAGIS) for WFD compliance, climate change impact assessment and Urban Pollution Management (UPM) studies.