Storm Overflow Assessment Framework (SOAF) Studies

SOCOTEC provides specialised Storm Overflow Assessment Framework (SOAF) studies to support water companies in evaluating combined sewer overflow performance and ensuring regulatory compliance.

What is the Storm Overflow Assessment Framework?

The SOAF is a regulatory methodology used to assess the environmental impact of storm overflow discharges on receiving waters. It combines flow, rainfall, water quality, and ecological data to determine whether overflows pose an unacceptable environmental risk and whether further investigation or investment is required.

The importance of SOAF Studies:

SOAF studies are critical for demonstrating that storm overflows are operating as intended and are not causing unacceptable environmental harm. Robust SOAF evidence helps water companies:

Meet Environment Agency expectations with defensible data
Identify high-risk overflows requiring intervention
Avoid unnecessary capital expenditure where impacts are low
Support WINEP investigations and AMP investment cases

Talk to our experts

James Teale

Operations Director - Water Quality

james.teale@socotec.co.uk 07855 958644

Our SOAF Study Services

Deployment of multi-parameter sondes for continuous water quality monitoring in receiving waters
Strategic placement of automated samplers for overflow event sampling
Installation of rain gauges to monitor precipitation events and correlate with overflow activities
River monitoring systems providing continuous assessment of receiving watercourse conditions
Flow measurement using acoustic Doppler current profiler equipment for accurate discharge quantification
Integration with Event Duration Monitoring (EDM) data to assess spill frequency and duration

Real-time water quality monitoring during overflow events using deployed sondes and river monitors
Automated sample collection triggered by rainfall events and overflow conditions
Laboratory analysis of collected samples to determine pollutant concentrations
Correlation of rainfall data with overflow performance and environmental impacts
Assessment of environmental impacts on receiving watercourses
Evaluation of compliance with regulatory standards and environmental objectives

Comprehensive reporting for Environment Agency submission
Support for Water Industry National Environment Programme (WINEP) obligations
Technical expertise to support infrastructure investment decision-making

Storm Overflow Assessment Framework Studies

Delivering Robust, Defensible SOAF Evidence

Our SOAF studies are designed to withstand regulatory scrutiny and provide confidence at every stage of the decision-making process. By combining high-quality field data, analysis, and a clear understanding of regulatory expectations, we deliver assessments that are technically robust, transparent, and defensible.

SOCOTEC works closely with water companies to ensure that monitoring programmes are proportionate, targeted, and aligned with Environment Agency guidance. Our independent approach ensures that conclusions are driven by evidence, supporting confident regulatory engagement and helping to avoid unnecessary or misdirected investment.