Why the radial flow is minimize by using buffer pond in infiltrometer test?

Radial flow is minimized in an infiltrometer test by using a buffer pond because it helps maintain a consistent water level, reducing the lateral movement of water away from the test area. The buffer pond creates a stable hydraulic head, allowing for more accurate measurement of infiltration rates. By limiting the radial flow, the test can better isolate the vertical infiltration characteristics of the soil, leading to more reliable results. This setup ensures that the observed infiltration is primarily due to the soil's properties rather than external water movement.