Lake-spring Sarva is in Nurimanovsky region of Bashkortostan near the village Sarva.Karst lake represents a way to the surface of an underground river flowing into the river Sarva. The length of the lake is about 60 meters, the width is 30 meters.The bottom is 38 meters of depth, and according to some sources, it is 49 meters. The discharge of the spring is about 10 cubic.The discharge of the spring is about 10 cubic meters per second.In 17 km Sarva flows into another river – Saldybash which is the tributary of Ufimka river.The lake water is clean and clear, has a bluish tint, but the colour can change depending on weather. The bottom can be seen in the depth of 12 meters. Water temperature is +3 at the bottom and to +5 degrees on the surface at any time of the year. The lake is of interest to experienced divers – extreme sportsmen.