Mtsvane Tba (Green Lake) is a lake in Khulo municipality, in the northern part of the Arsiani range. Slightly mineralized, clean, transparent and drinkable. There are no fish in the lake. Elevation 2,058 m above sea level. Surface area 0.05 km². Greatest depth 19.4 m. Fed by snow, rain and groundwater, draining away underground. The water level is high in spring and low in winter.