Study on water resources monitoring in subsided water areas based on unmanned surface vehicle and GIS

For five pairs of mines such as Zhangji Mine,Xieqiao Mine,Dingji Mine,Guqiao Mine and Gubei Mine,large-scale mining of coal in the past has formed a large range of subsided water areas near the mines,and most of the subsided water areas are in a state of no use and cage fish farming .In order to rationally utilize the water resources of subsided water areas,it is necessary to accurately obtain the reservoir capacity and underwater topography.Based on the unmanned surface vehicle advantages of high precision in water depth measurement and target detection and automatic obstacle avoidance,the unmanned surface vehicle is controlled by a remote control for a small area of air-sinking water within forty thousand m2,and for large-area cages (bamboo nets)and in special water areas such as large-scale subsided water areas of more than forty thousand m2,the water depth was measured by designing the route of unmanned surface vehicle on the surface vehicle-controlled computer.For the special subsided water areas covered by river rafts and weeds,through a person on the motor boat using a remote control for the measurement of unmanned surface vehicle.Regardless of the type of subsided water areas,the survey of unmanned surface vehicle adapt a grid-like navigation route and used the data acquisition mode of the marking point,the marking interval is set to 5 m.The water depth data signal was corrected by the water depth processing software,and the corrected data was imported into ArcGIS to generate a water depth distribution map.The Delaunay triangulation was constructed by MATLAB programming,combining with ArcGIS to generate underwater terrain and the “surface” tool was used for the capacity calculation of underwater reservoir.Taking the Huainan mining area as an example,the water depth measurement and capacity calculation of underwater reservoir as well as underwater terrain construction through TIN were carried out in the subsided water areas near the five pairs of mines namely Zhangji Mine,Xieqiao Mine,Dingji Mine,Guqiao Mine and Gubei Mine in the dry season and the flood season respectively.By using the virtual CORS reference station technology combined with the measuring rope to measure the checkpoints of the subsided water areas near the Gubei Mine and the Zhangji Mine,and comparing with the measurement results of the unmanned surface vehicle at the correspofnding checkpoints.The calculation results show that the capacity of underwater reservoir of the measured subsided water areas in the dry and flood seasons is one hundred and seventy six million m3 and two hundred and nineteen million m3 respectively,and the underwater terrain map is accurately obtained.The conclusion is that the unmanned ship measurement has higher accuracy and higher efficiency,and results of water resource monitoring can provide enough information reference for the reasonable use of the large subsided water areas nearby the five pair of mines.