Snowmelt lysimeters: design and use

Snowmelt lysimeters have become a widely used tool in snow hydrology. They have been used to develop and evaluate procedures for estimating snowmelt volume and timing, evaporation, water transmission and storage, and the mass balance of snowpacks. While their basic objective of collecting and measuring the liquid water outflow at some depth within the snowpack seems simple enough, many practical difficulties exist. The hydraulic characteristics of water flow through snow and its collection determine the effectiveness of lysimeter installations. The presence of an impermeable collection pan within the snowpack generates an 'end effect' analogous to a perched water table above the lysimeter interface. This end effect largely determines collection efficiency, dead storage, start-up time, and response of the snowmelt lysimeter. Over three dozen snowmelt lysimeter designs are summarized, tabulated, and compared. Some basic guidelines for lysimeter installation and operation are presented.