As the winter groundwater monitoring season begins - and with extreme weather events becoming increasingly common - Richard Holloway, Geo-Environmental Partner at Ridge, shares why timely testing is essential for resilient drainage design.

Storm Benjamin recently brought heavy rain and flood alerts across England, while groundwater levels in many regions remain below normal after a record-hot summer. This contrast highlights the importance of accurate winter groundwater monitoring and soakage testing – critical for planning applications and designing resilient drainage systems. 

Why timing matters
Winter groundwater monitoring season typically runs from November to April, when levels are at their peak. Capturing this data ensures drainage designs are based on realistic conditions, reducing the risk of flooding and structural issues later. 

Planning and compliance
Winter groundwater monitoring captures peak water table levels – data that informs sustainable drainage systems (SuDS) and supports planning applications. Many Councils, guided by their Lead Local Flood Authority (LLFA), require this evidence before granting approval. LLFAs play a critical role in assessing flood risk and ensuring developments meet national and local drainage standards. 

Accurate monitoring is essential for compliance with SuDS requirements, which typically stipulate that drainage features such as soakaways must be installed with at least one metre of clearance between the base of the SuDS feature and the groundwater level. Without reliable data, designs risk non-compliance or failure under extreme weather conditions. 

“Groundwater testing isn’t just good practice – it’s often a planning condition for many Councils,” explains Richard Holloway, Geo-Environmental Partner at Ridge. “Missing the winter monitoring window can have serious consequences. If you don’t capture peak groundwater levels now, you may have to wait an entire year before testing is possible, which can delay development and increase costs.” 

Our approach
Our Geo-Environmental specialists work closely with Civil Engineering teams to deliver site-specific insights. This integrated approach helps clients make informed decisions and design drainage systems that stand up to both drought and deluge. 

Act early
Starting monitoring early in the season is key to capturing representative data. If your site requires monitoring this winter, contact Richard Holloway or visit https://ridge-old.mc-staging3.net/expertise/geo-environmental-consultancy/