A system for observing a flow characteristic of a fluid is provided. The system includes a nadir-facing sensor, an angle flow sensor, and processing circuitry. The nadir-facing sensor and the angle flow sensor are both provided at a distance above the fluid. The nadir-facing sensor and the angle flow sensor are both radar sensors. The processing circuitry is configured to receive sensor data from the nadir-facing sensor and the angle flow sensor. The sensor data includes at least one of a fluid speed or a fluid surface level. The processing circuitry is configured to determine the flow characteristic based upon the sensor data.