Percolation rate can be measured using Drain Gauge. The a-half-meter tall Drain Gauge is buried directly in the ground to measure flow rate in unsaturated soils. One of the challenges with lysimeter measurements is that water tends to flow around receptacles buried in the ground. The drain gauge uses an ingenious duct and wick design to apply a constant tension and keep the flow rate within the gauge equivalent to the flow rate in the surrounding soil.