Metro Utility Diversion Survey in NCR

Updated: 23 October 2026

What is a metro utility diversion survey?

A metro utility diversion survey is the investigation that tells a metro or rapid-rail project which buried services stand in the way of its civil works, and where those services can be moved. It has two halves:

1. The footprint scan – utility detection with radar and an electromagnetic (EM) cable locator over each pier position, station entry, station box, ramp and casting yard, to list what lies beneath.
2. The corridor scan – the same methods along the strip where a diverted water main, sewer or HT cable is proposed to run, so the new route does not hit something else.

The output is a set of marked positions, approximate depths and a signed report. Designers then decide, service by service, whether to divert it, protect it in place or adjust the structure. Our metro and rail sector page covers the wider survey scope for these projects.

Why do NCR metro corridors need so much diversion work?

Metro and rapid-rail lines in the region – the Delhi Metro run by DMRC, the Noida–Greater Noida Aqua Line, Rapid Metro in Gurugram and the Delhi–Meerut Namo Bharat corridor built by NCRTC – mostly follow existing arterial roads. Those roads already carry the busiest service bands in the city.

Under a single carriageway you can find:

• HT and LT underground cables of the local power distribution company (DISCOM) – Tata Power-DDL, BSES Rajdhani or BSES Yamuna in Delhi, DHBVN in Faridabad and Gurugram, and the UP distribution companies in Noida and Ghaziabad;
• Delhi Jal Board or municipal water mains and trunk sewers;
• city gas lines laid by IGL;
• several telecom operators' OFC ducts, often laid at different times;
• street-light cables, signal cables and storm drains.

Every viaduct pier needs clear ground for its pile group, and every underground station box displaces a large block of road. Records for these services sit with many different owners, and they rarely agree with each other. A field survey is the only way to see what is actually there before piling rigs arrive.

Which types of diversion survey does a metro package use?

Pier and pile position scans

On elevated sections, each pier location is scanned on a close grid covering the pile cap area plus a working margin. Even one unrecorded cable under a pile can stall a span.

Station footprint surveys

Elevated stations need entry, lift and stair positions cleared on the footpath. Underground stations need the whole box and its entry shafts covered, which is a much larger area.

Diversion corridor surveys

Once a service must move, the proposed new alignment is scanned end to end. This is a normal linear route survey, billed per metre.

Crossing and bore-path scans

Diverted lines often cross a road by HDD. The bore path and both pit locations are scanned so the drilling plan avoids live cables and other metallic utilities as well as plastic pipes; our HDD route survey page explains this step.

Depot and ramp areas

Ramps and depot entries cut across service bands at an angle, so they are treated as small areas rather than straight lines.

Which terms come up in diversion survey reports?

• Footprint – the plan area a structure will occupy, plus the margin a contractor needs to work safely.
• Diversion – shifting a service to a new route, temporarily or permanently, so civil work can proceed.
• Protection in place – leaving a service where it is and guarding it, when moving it costs more than designing around it.
• Depth of cover – the vertical distance from road surface to the top of the service. Radar gives an estimate whose accuracy depends on soil type and moisture content, since wet ground brings signal attenuation that weakens the returning pulse.
• Unattributed find – a detected line no owner has claimed, reported as such rather than guessed.
• Quality level – a grading of how each piece of utility information was obtained; our SUE survey page explains the levels.
• L-section – a depth profile of the detected services along the route, ordered at ₹32 per metre instead of the standard ₹24.

What should a good diversion survey deliver?

A survey that designers can actually work from has a few clear features:

• Services sorted by type and likely owner, so each DISCOM, water body, gas company or telecom operator can be sent only its own lines.
• Position and estimated depth at each measured point, noting whether radar, EM or both picked the service up.
• Stated limits: stretches that could not be scanned because of parked vehicles, barricades or standing water, and the penetration depth radar reached on each section.
• Ground marking in utility colours, so the trial-pit team and the piling crew see the same picture.
• Critical points flagged for trial pits or boreholes, which we can open on request where a depth has to be proved.

CAD or GIS drawing sets for the designer can be prepared from the survey, and they are quoted separately. The CAD/GIS utility mapping page sets out what those sets look like.

How should contractors plan a metro utility diversion survey?

1. Survey before the diversion design is frozen. Footprint data changes pier positions and diversion routes; arriving late means redrawing.
2. Send the alignment as KML with pier, station and ramp footprints marked, plus whatever owner records the project has gathered so far.
3. Split the scope into footprints and corridors, so the quote shows area scans and linear runs separately.
4. Agree working windows. Many arterials can only be scanned at night. Night working and traffic arrangements sit outside the per-metre rate, and the timing of road access should be checked with the road-owning agency.
5. Group stretches. Billing starts at 4 km per order, so short footprint lists are better ordered together with diversion corridors.
6. Plan trial pits at the end, only at points where the design depends on an exact depth.

Corridor-specific detail for each city is on our Delhi, Noida and Gurugram survey pages.

How are diversion survey records kept up to date?

A diversion survey describes the ground on the day it was scanned. Once services are shifted, that picture is out of date, so the record needs care:

• Keep the signed report as the base document. Ground marks fade within days on a busy road; the report does not.
• Mark each service's status after diversion – shifted, protected in place or abandoned – rather than deleting it from the record.
• Add as-built positions for the diverted lines once they are laid, and scan again where the new route was changed on site.
• Hold layers by owner, so a later query from one DISCOM or operator can be answered from its own layer.
• Keep version dates on every drawing issue, so the piling crew never works from a superseded sheet.

What does a diversion survey cost in Delhi NCR?

Linear and footprint work is priced per metre of scan line: ₹24 for a standard survey and ₹32 where an L-section depth profile is ordered. Inside Delhi NCR, each order is billed for a minimum of 4 km and the ₹1,00,000 project minimum used outside the region does not apply. GST is added to every bill.

Bigger packages are discounted on every metre: a quarter off past 100 km, 40% past 500 km and half past 1,000 km. Anything beyond scanning – getting crews to site, night working, traffic control or permits, and CAD/GIS sheets – appears as a separate quote line. Full slabs are on the GPR survey price list.