Taking a new approach to risk-based profiling of gullies

KaarbonTech Asset Management helps over 50 local authorities define and manage their risk on a day-to-day basis, with software systems and services built from the ground up. The team understands every step of the process, having experience ‘on the job’ themselves. Their solutions drive productivity and proactive maintenance, protecting revenue and allowing clear, accurate communication across councils and contractors.

Back in 2018, the Department for Transport recommended that local authorities maintained their roads using a ‘risk-based approach’. The guidance, called ‘Well-managed Highway Infrastructure’, or ‘the New Code’, stated that:

“Authorities should adopt a risk-based approach and a risk management regime for all aspects of highway maintenance policy.”

This included drainage, however many councils did not have an accurate history of cleansing data to align to a risk-based approach. Instead they simply resorted to increased maintenance routines, such as cleaning the gullies on an A-road more often than an unclassified road; or prioritising those with a high silt level.

The results of a survey across eight networks and one million gullies showed that 20% to 60% of gullies are cleaned unnecessarily each year. With clear savings to be made across productivity, revenue and resource, a new data-led risk-based approach could yield benefits to many local authorities.

Harnessing GIS for risk-profiling

Having committed significant time and resources to researching a risk-based approach to drainage management, KaarbonTech Asset Management identified a way of harnessing GIS to automate a maintenance programme, based on risk. Engaging with their customers – local authorities around the country – KaarbonTech also developed an understanding of common approaches and the similar aspirations for managing gullies.

Their research revealed over 20 datasets that could assist with risk management, that the majority of local authorities could access. They also discovered that, whilst other highway assets were being given a single risk score, gullies had two distinct properties that should be taken into account:

  1. How important the location was
  2. How vulnerable the gully was to failure or becoming blocked

Assessing the location looked at:

  • Road Speed
  • Road Hierarchy
  • In a known flood zone?
  • Urban or Rural
  • Known priority zones
  • Other geographic Influences – near hospital or accident blackspot

Assessing the vulnerability looked at the cleansing history of the gully, including:

  • Silt Levels
  • Whether it had been visited as an emergency
  • If it was left operational after a clean
  • Its condition in relation to previous visits
  • Any open service requests

Combining multiple data sources to profile a network allowed more accurate decisions to be made, and KaarbonTech further developed their Gully SMART system to analyse and process this data.

Increased knowledge = Better decision-making

KaarbonTech’s Gully SMART management software allows risk modelling scenarios to be run by road section or individual gully, to cater for differing preferences to approaching maintenance. Using a combination of multiyear inspection history, geographic or other asset influences, importance of the road usage, risk to life, defects and IoT data, the modelling system ranks each gully or pipeline.

With each of these factors scored as a percentage, the Gully SMART software creates a matrix showing the number of gullies that are similarly scored across the network. With a cycle-length applied to each group of similarly-risked gullies, risk models can be easily compared and an appropriate cleansing programme created. Taking into account crews’ productivity as well as budget, local authorities are able to understand the number of cleanses achievable with the resources available. All this information is available to view on a map, allowing precise monitoring and planning, and reports can be run, extracting the information required and giving a clear, comprehensive overview.

gully risk-based profiling and matrix

Recognising the benefits

This analysis allows local authorities to understand the real-world risk that gully failure might cause. Being able to compare risk models quickly allows strategic planning, ensuring the drainage network is cleansed efficiently and proactively. This reduces flooding, which is linked with road damage and collisions leading to injury and death.

Bath and North East Somerset Council has seen the benefits of using Gully SMART for risk profiling. With an aging network, and a mix of urban and rural roads, they were able to look at their network geographically, assessing the gullies using the software and seeing where the problem areas were. This meant that they could target their resources more effectively.

George Bottin, Principal Engineer at Bath and North East Somerset Council praised the system, saying, “It’s vital that we have information that we can gather with KaarbonTech to understand how the network’s performing so we can target the right areas. KaarbonTech have got experience of the sector and the tools to look at your network in the wider sense and get a better understanding of where some of the challenges are”.

Northumberland County Council have also benefited from the Gully SMART system. Highways Manager Martin King reported that, “KaarbonTech has revolutionised where we were originally to where we are today. Risk scoring, for the future of the industry, within highways as a whole, is fundamental for it being a success, it cannot go any other way now. We’ve tried every other direction, and now risk scoring is the only way for it to move forward”.

Within two years of using KaarbonTech software, 86% of their customers have shifted to a proactive cleaning regime, saving time and resource and revenue.

Click HERE to learn more about Gully SMART

This article has been featured in the latest Highways Magazine (June 2021):

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Leigh Harris