Qanat a.k.a. karez (Environmental Profile Baluchistan under my RG profile, figure 2.1) could be probably identified on airborne lidar by their shafts at more or less regular distances. Your search area can be minimized by pre-selection of suitable terrain for qanat. The reference figure may assist.

The qanat in Iran, Balochistan and NW China did not seem to be dug along surface tracks, but underground from shafts, the latter still observable by their man-made micro-relief.

This question is very difficult to answer without knowing what area you are referring to. Look at the availability of aerial images for your study area, if you have availability try the sentinel 2 satellite images. You can also try with some commercial images, but you will have to pay for it but you will gain in spatial resolution.

Hi Mannan,

Are the qanat's track superficial or underground? if they are superficial, you can use thermal bands. If the qanat are underground, I think you can use Ground Penetrating Radar for this purpose.

Good Luck,

Reda

Ground penetrating radar would be okay for this, although affected by electrical conductivity, it can still detect qanats within the range of 15m

Please searching for:Determine the route of the aqueducts using remote sensing and electrical resistance measurements

And use as Quikbird &landset images,

But the low number searching for this subject

https://www.researchgate.net/publication/331076568_Global_Warming_Mitigation_Through_Carbon_Sequestrations_in_the_Central_Western_Ghats/stats

https://www.researchgate.net/publication/323180165_Salient_Ecological_Sensitive_Regions_of_Central_Western_Ghats_India

https://www.researchgate.net/publication/332331409_Sustainable_Management_of_Bannerghatta_National_Park_India_with_the_Insights_in_Land_Cover_Dynamics

https://www.researchgate.net/publication/324650411_Geoinformatics_based_Valuation_of_Forest_Landscape_Dynamics_in_Central_Western_Ghats_India

https://www.researchgate.net/publication/328734729_Conservation_and_Sustainable_Management_of_Local_Hotspots_of_Biodiversity

https://www.researchgate.net/publication/260192602_Land_Surface_Temperature_Responses_to_Land_Use_Land_Cover_Dynamics

thermal and radar RS data should work well if you your work is on superficial or near-surface qanat's. However, dryness of the soil, its wetness as well as spatial resolution will play major role on the accuracy of your results!

regards,