Rethinking maintenance SUDSnet International Conference 2012 Multiple Benefits from Surface Water Management 4 th & 5 th September 2012, Coventry University

Filter Drains on the UK’s High Speed Road Network Dr. Gordon Rowlands, Technical Service Manager

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT SUDSnet Conference 2007

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT SUDSnet Conference 2007

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT SUDSnet Conference 2007

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT Water Management Services, 2012 Asset Inventory Accurate GPS asset location Condition Surveys Variety of CCTV techniques. HAWRAT Technical Services Our in-house team can process data into any format you require. Remediation No-dig pipe repairs and ‘high pressure water jetting’ to fix problems Pollution control measures from verge to outfall

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT SMART view Survey Approach, 2012

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT Drainage Services, 2012 The STONEmaster ® process returns filter drain media to its optimum performance. Introduced to the market in 2003 with a fleet of 4 units now operational. BeforeAfter

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT HA guidance on assessing drainage condition (1) (August 2012)

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT HA guidance on assessing drainage condition (2) (August 2012)

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT HA guidance on assessing filter drain structural condition (1)

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT HA guidance on assessing filter drain structural condition (2)

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT HA guidance on assessing filter drain service condition (1)

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT HA guidance on assessing filter drain service condition (2)

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT Recent trial hole data (1)

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT Recent trial hole data (2)

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT Recent trial hole data (3)

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT Conclusions from trial holing The structural condition of filter drains is often poor and very variable due to poor compliance with Type B specification throughout the construction Poor service condition further compounds below par performance arising from a failure to meet the required spec The StoneMaster process will restore both the structural and service condition of filter drains, returning Type B stone to the drain, with imported Type B top-up to make up for missing aggregate and bring the filter drain to the right level Trial holing is OK as far as it goes, but the client needs better information with minimum delay and reduced costs, and needs to be able to more readily identify where refurbishment will give the best return on expenditure.

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT VACex - the no dig approach to sampling Benefits Much quicker than trial holes 150mm hole yielding ~ 20kg for 750mm depth Gives ‘window’ into condition at selected depths Will not damage carrier pipe No safety issues with trench collapse Sample hole readily made good or retained for site testing Daytime operation Less plant intensive

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT SMART scan Benefits Relatively high speed Continuous condition dataset Low-cost solution Much reduced need for samples Mitigates risk of service strikes Daytime operation Based on Ground Penetrating Radar, this enables sub-surface surveying to a depth of 750mm. Condition surveys of filter drains can be undertaken over long distances

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT Silt Predictive Model Predicts the on-going levels of silt reaching filter drains from highway run off, in line with HD 219/09 Benefits Provides insight into likely loss of filter drain performance due to sediment transport off the highway during rainfall events Can help assess maintenance intervention priorities and tailor to available budgets Funding can be aimed at the very bad filter drains, ahead of the bad and the poor!

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT Where are we now in 2012? Condition assessments no longer limited by trial holing and visual assessment The client is getting better information Reduced survey costs and time to deliver Client can integrate with other data to get the best return on their expenditure.

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT Final Word: Waste Management & Sustainability (1) The removal of highway derived pollutants will always generated contaminated waste. All waste must be categorised as hazardous or non-hazardous. Filter drains are known to be highly effective in dealing with the pollutants in highway runoff and hence filter drain arisings will always be contaminated. However arisings to date have always been non-hazardous. The typical amount of arisings per shift is 60t for 300m of filter drain with stone import of around 40t to make good Refurbishment is almost always undertaken at night and hence access to temporary storage is important

TECHNOLOGY // INFRASTRUCTURE // DRAINAGE // WATER MANAGEMENT Final Word: Waste Management & Sustainability (2) Because of their relatively high mineral content, typically 50% 10-20mm and 50% < 10mm, arisings are generally destined for inert landfill, as overall quality & quantity of arisings does not often merit recycling. WAC testing on pre-production samples is important because of the 8-10 day lead time for WAC testing of samples. In-house TPH testing is undertaken as a lead indicator on the overall level of contamination in arisings and regularly verified by external lab testing. Recycled aggregate complying with WRAP protocol and HA Standards is always used in preference to virgin stone for top-up if a local supply to Type B specification can be secured.