Sandwell Metropolitan Borough Council

Cost Neutral Gully Surveying


  • Drainage | Gully


  • Advice
The Problem

Inadequate knowledge of highway drainage assets

Sandwell could not quantify its entire highway drainage asset to create a meaningful cleansing programme.

Understanding the borough drainage network was an important starting point to create a gully cleansing programme. Without detailed knowledge of the number and location of each gully, the council was working blind. Sandwell Metropolitan Borough Council (MBC) commissioned KaarbonTech to undertake a comprehensive survey of its nearly 41,000 gullies.

Our Approach

Thorough survey reveals drainage network gaps

A walked survey took place to identify the entirety of the drainage network.

Over a period of 12 weeks, KaarbonTechs fully trained surveyors walked the entire network carrying out detailed inspections of nearly 41,000 individual gullies. They established that approximately 9,500 gullies were not recorded in the system and 23% of the entire system was unknown. The process involved the surveyors dipping each gully pot to ascertain the quantity of silt in relation to its capacity. A new enhancement for KaarbonTech – the silt slider - enables its surveyor to choose from a visual representation on their device, to record the capacity of each pot. The system records the percentage of silt found to the nearest quartile. A visual map-based version of the borough and silt report was created displaying those gullies full to 50% capacity or greater.

The Result

Efficient risk-based gully cleansing programme

A meaningful risk-based cyclical gully cleansing programme could be produced for Sandwell.

All newly found gullies were added to the Gully SMART software. With the new and auditable information displayed visually, the team could establish the areas most in need of cleansing to give the programme initial focus. Sandwell MBC was able to create a risk-based gully cleansing programme created on the demands of the network, using the knowledge of gully condition and capacity. Overall Sandwell could create a risk-based cyclical programme for all highway gullies with its enhanced data whilst additionally scheduling any necessary gully repairs. By working smarter, the budget savings associated with having a risk-based gully cleansing programme warrant that gully surveying becomes a most effective cost-neutral exercise.


KaarbonTech's gully programme data is highly valued by councils, for enabling a cost-neutral service.

Mark Entwistle, Managing Director, KaarbonTech,

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