Hydrology and water resource surveying buoy

The hydrology and water resource surveying buoy comprises a first mounting plate, a floating body, an extension assembly and a fixing assembly, the floating body is fixed to the outer wall of the bottom end of the first mounting plate, the extension assembly is arranged on the outer wall of the top end of the first mounting plate, and the fixing assembly is arranged on the outer wall of the top end, located above the extension assembly, of the first mounting plate; a second mounting groove is formed in the outer wall of the top end of the first mounting plate, a plurality of first mounting grooves are formed in the outer wall of the top end, located on the periphery of the second mounting groove, of the first mounting plate, and the first mounting grooves communicate with the second mounting groove; according to the buoy, expansion of the floating block can be conveniently adjusted according to wind speeds and water flows of different water areas through the arranged expansion assembly so as to adapt to diffe