Civil Engineering

Drainage Survey & Remediation
Through investment in to the latest technologies and development of our experienced in-house teams, Carnell provide the most reliable and complete technical surveys solution.

An in-depth knowledge of highways drainage

Our survey & remediation capability reflects Carnell’s strong commitment to innovation and process development. From delivering the first DDMS survey for National Highways in 2005, our offering has evolved over the years, fuelled by continual improvement and an appreciation of client needs. 

GPS Asset Inventory Surveys

Our experienced in-house team of GPS surveyors use the latest Spectra Precision Mobile Mapper (MM60) kit and ERSI Collector software. This provides high accuracy and a ‘live-stream’ instant upload to Arc GIS Online, improving reliability, speed and quality of data, its processing and output.

On the highways, point, continuous and region assets are captured to the CD 535 specification to enable inventory information to be uploaded to DDMS.

CCTV Condition surveys

Our fleet of customised survey vehicles are equipped with zone 2 explosion proof MiniCam camera equipment for safe and accurate assessment of any size of pipe. Latest WinCanVX software provides the added functionality of shapefile roundtripping.

All our rig managers are experienced in highways drainage and trained to OS19x to undertake a comprehensive CCTV condition assessment of your piped drainage network.

On the highways our teams undertake the surveys to CS 551 specification with the resulting condition shapefile uploaded to DDMS.

Jetting / Pre-cleansing

We supply a flexible resource that ‘jet and suck’ to either pre-cleanse pipework in advance of camera surveys, or provide routine / reactive maintenance including emptying Pollution Control Devices.

The high volume low pressure (HVLP) recycling units have an integrated suction unit on them which de-silts the collected water before re-using it.

No-dig remediation

Our Remediation team use trenchless techniques to deliver safe and less-disruptive pipework remediation. 

We specialise in design ECI, and assist clients along the entire process, from analysing CCTV data through to round tripping the DDMS shapefile – updating the condition information of remediated drainage assets where required.

Depending on the structural defect, the methods used include CiPP lining, patching and robotic cutting. These interventions provide a permanent solution, eliminating the need for excavation and the resulting safety and environmental impacts.

We manage and undertake ‘Find & Fix’ Remediation schemes, surveying unknown drainage and carrying out trenchless remediation removal in the same visit. This saves time and money in eliminating the requirement for design and multiple roadspace occupancies.

Technical services team

We have an in-house team that process and undertake quality assurance on WinCan and GIS data to CD535.

Survey reports including CAD drawings can be fully customised to client specifications.

Supporting them, our GIS Development team create programmes to automate processes for improved speed and value.

This includes Drainage Viewer (DV2), our online portal which uses ArcGIS to provide efficient and intuitive mapping, logging all asset data including video, photos and condition for interrogation and analysis. This asset management tool can use client datasets such as pavement condition and SES.

Chamber Laser Scanning

We have two CleverScan chamber laser scanners to undertake safer, quicker, more detailed inspections of catchpits and manholes.

Once positioned over the chamber and activated, the camera-head automatically lowers itself to capture a full scan in a couple of minutes, which is twice as quick as a standard manual survey.

Like all our drainage surveys, the information is CS 551 compliant and can be observed on WinCan VX viewer. This shows the chamber in high-definition video format and as a 3D point cloud, giving better information to designers.


Our drainage and remediation experts can provide Value Management advice and help build schemes alongside client drainage teams. We second our employees to client teams in several areas across the country to provide them with flexibility and additional resource when required.


The traditional DDMS survey using GPS, Jetting & CCTV to determine all asset inventory and detailed condition.


Surveys of unknown outfalls (for each catchment), culverts & balancing ponds through desk study and walkover survey.


A ‘quick assessment’ of the condition and drainage connectivity, which we undertake using our SmartView pole mounted cameras.


Reporting sediment levels, voids and water content in the roadside filter drains. We do this quickly and efficiently using our SmartScan survey vehicles, as detailed in our Filter Drain Recycling capabilities. 


Logging the internal profile of
pipework alongside a CCTV survey.


Determining whether drainage inventory information on DDMS represents a true record of visible surface point assets.


Condition survey of ditches including , silt levels, cross-sectional profile and collection of soil samples to provide List of Waste (LoW) codes and European Waste Classification (EWC) information.

Record Digitisation

Where drawings exist of an un-surveyed area, our Technical Services team are able to geo-reference and digitise the assets. This provides a quick although unverified method of generating an electronic location record of the drainage network.

When working on the National Highways strategic road network, the digitised assets are uploaded to the DDMS drainage database.

Balancing Pond Surveys

Carnell have surveyed hundreds of balancing ponds using GPS Surveys with CCTV Condition Surveys and Site Clearance activity where necessary to provide accurate drainage surveys alongside Access, Security and Safety assessments. As well as the standard information (Point and Continuous Items) the ponds’ (Region Items) can be uploaded to DDMS.

Culvert Surveys

GPS Surveys are combined with a variety of CCTV survey techniques to gain the maximum amount of information on a culverts service and structural condition. We can pump out culverts prior to using ‘jack-up’ cameras, floatation devices or SmartView. Survey data can be uploaded to DDMS or tailored to ‘Structures’ teams’ requirements.