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IAP – PDAS Investigation, HPWJ & CCTV Works

Case Study


In October 2011 the transfer of the private sewers lead to the water authorities adopting thousands of kilometres of uncharted sewer. PDAS investigation works were then undertaken to effectively survey and map their newly adopted assets.

o    Issues identified were:

  • Water authorities had very little knowledge of the transferred sewers.
  • The condition of the transferred sewers was not known.
  • Corporate mapping systems were out of date, as the location of the adopted sewers was not known.

What We Did

We liaised with the local Highways Authority in order to properly raise notices and obtain the highways permits. We then produced a programme plan, which gave the client a realistic on site duration and completion date.

o    Pre Start.

  • We realised that collecting and managing this data would be a huge challenge for both our site and back office staff due to the volumes and no existing system or processes.
  • We realised we had to look at new ways of collecting this data from site, manage the process in a more efficient way and make the data available to the Water Authority corporate systems.
  • CALM developed an App that could be used in real time on site, which would cut down on the client specific paperwork and increase productivity. Validation of information takes place at point of entry to improve the quality of data received from site.
  • Lightweight mobile optimised forms which have been designed to work in poor connection areas.
  • Mandatory fields prevent surveyor’s by-passing key information requirements.
  • We also constructed a Cloud Based Data Hosting Site (PDAS Mapping System), to store and display the survey information captured on site. The site was populated in real time directly from the App.
  • All affected properties were letter dropped the week before work started, to inform them of our presence and what work would be carried out.

o    On Site.

  • The investigation & survey work was carried out by our highly experienced CCTV Survey and HPWJ teams.
  • The vehicles used on site were a 24 Tonne Sewer Jetting & Vacuum Unit (combination unit) and Mainline CCTV Survey Unit, with the capability to clean and survey pipes from 100mm up to 1000mm.
  • All the transferred sewers within the site boundary were plotted, de-silted and CCTV surveyed using Wincan 8 reporting software.
  • GPS co-ordinates of each transferred manhole cover were gained to enable teams that visit site in the future to easily locate access points.
  • Were possible all root infestation was removed using a rotary Warthog HPWJ nozzle.
  • Any major defects that were found, such as collapses or anything that would cause a blockage – were reported to the client directly from site. Therefore enabling the client to respond quicker and reduce the risk of any incidents.
  • On several occasions our site teams located properties where a foul sewer had been connected into a surface water drain, resulting in contamination of a water course. Any cross contamination was reported immediately from site and the sewer would be re-routed to reduce the fouling of the water course.
  • The above 2 items are visible in real time on the PDAS Mapping System and highlighted from site using the App via an “Issue Log” email notification and back up phone call.
  • Bi-weekly meetings were held with the client to update them on any delays that may have caused by the sewers condition, access issues etc…
  • All transferred sewers mapped, cleaned and surveyed.
  • All transferred manholes are now located, allowing future works to be undertaken without delay.
  • The sewerage system in the area is working more efficiently.
  • All blockages have been removed, therefore reducing the risk of flooding and customer complaints.
  • The client was issued with a full CCTV survey report, including a condition report for each pipe length, photographs of grade 4 & 5 defects, video footage of each pipe length (on DVD) and a list of all defects that required some remedial action/repair.
  • All defects that have the potential to cause issues in the future have been highlighted, enabling the water authority to proactively plan sewer repairs.

The Results

Another successful project from CALM Survey Solutions Ltd.

For more details please contact us or visit www.calm-solutions.com

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