Background The Unmanned Aerial Vehicle (UAV) remote sensing is a new technology for soil and water conservation monitoring. It fills the gap between satellite remote sensing and surface observation, which provides a flexible method for users. However, as to combine this new technology with the criterion and specification in soil and water conservation monitoring in construction projects, more practices are needed.

Methods We conducted a case study for the application of UAV remote sensing technology in soil and water conservation monitoring. This case study was based on a practical construction project called "Water Resources Allocation for the Region of North Hubei" and was divided into three parts: the acquisition of basic remote sensing data, the extraction of monitoring information and the application of information in monitoring work. First, we took the aerial images of some typical regions of the project, then using the software Agisoft Photoscan Professional, we processed the raw data to generate two products, the Digital Elevation Model (DEM) and Digital Orthophoto Map (DOM) for each region. Finally, based on the criterion and specification in soil and water conservation monitoring in construction projects, the application of extracted information from the DEM and DOM results aims to apply effective information into practical monitoring work

Results The result showed that horizontal resolutions for all the DOM were less than 0.05 m and those for all the DEM were less than 0.2 m. The computer automatic classification was much faster than visual interpretation for classifying the land cover type. However, the computer automatic method had some problems of misclassifying the shadow of the water soil and coverings into vegetation. Based on the UAV method, the disturbed production and living areas in construction project for the exit of Jihong Tunnel, the entrance of 16^th section, the 1^th and 2^th disposal area in the 16^th section were 16 562.2 m², 5 153.8 m², 4 268.6 m² and 19 108.5 m², respectively. The volume of the 1^th and 2^th disposal area in the 16^th section was 11 thousand m³ and 172 thousand m³. The 1^th and 2^th temporary cover area of the 1^th disposal area in the 16^th section was 166.9 m² and 1 229.9 m², respectively. Compared to the statistical results of the construction organization, the monitoring values based on the UAV and the traditional methods were mostly controlled in 10% of the difference, meeting the relevant requirements. However, the monitoring efficiency of the UAV WAS three to five times of that by the traditional methods.

Conclusions These monitoring information are all required by the criterion and specification in soil and water conservation monitoring in construction projects. Therefore, by applying UAV remote sensing technology in soil and water conservation monitoring, we may acquire some essential information quickly and easily. Our study shows the feasibility of this method and also reveals that compared to traditional monitoring methods, the information extracted by this method are more accurate and can also save the monitoring cost and improve the monitoring efficiency.