Currently, monitoring the ecological conditions of watercourses is overly unitary and inefficient and is burdened by high costs. A cost-effective, efficient, self-powered sensor for incorporating the Internet of Things (IoT) into the surveillance of riverine ecosystems is lacking. This manuscript introduces a device designed for energy harvesting and sensing through a triboelectric–electromagnetic generator (CX-TEHG). The CX-TEHG is composed of a wind-driven electromagnetic generator (F-EMG), a river-driven electromagnetic generator (W-EMG), a triboelectric nanogenerator for measuring flow velocity (W-TENG), and another triboelectric nanogenerator for gauging the speed of floodwater level rise (F-TENG). It employs planetary gears to achieve a 6-fold increase in speed, facilitating efficient multienergy collection from wind and river currents. CX-TEHG achieves a peak power output of 183 mW and a power density of 373.5 W/m3 under environmental conditions featuring a wind speed of 4 m/s and a flow velocity of 0.5 m/s. This study developed a cost-efficient signal acquisition system and a mechanism for information transmission via a 5G module. Alerts are issued on both upper-level computers and mobile devices for river flow velocities exceeding 2.8 m/s and water levels reaching specified locations; thus, an innovative solution for applying the Internet of Things in riverine ecological monitoring is presented.