Product description: surface runoff is the flow of water that occurs when excess water from rain, meltwater, or other sources flows over the earth's surface. This might occur because soil is saturated to full capacity, or because rain arrives more quickly than soil can absorb it. Surface runoff is a major component of the water cycle. It is the primary agent in soil erosion by water. Qt series tipping bucket flowmeter can be used to monitor no-pressure, low-head, and small discharge flow of surface or underground runoff. Features Stainless steel, suitable for long-term use in extreme environment Data logger achieves nema 6 and ip67 standard, suitable for outdoor use Power supply is simple, cr-2032 3v lithium battery, no need of solar panel and storage battery Suitable for monitoring of surface runoff and underground runoff