Smardonės Spring is a unique karstic spring and an important hydrogeological natural monument located in the Biržai district, within the Biržai Regional Park, on the grounds of the Likėnai Rehabilitation Hospital. This spring is renowned for its healing properties and distinctive hydrogen sulfide odor, which has attracted the attention of locals for many years.
The water from the spring has a bitter taste and a sulfurous odor reminiscent of rotten eggs, so locals have historically used it not for cooking but for other purposes. The water was suitable for baking bread, bathing, drinking for medicinal purposes, and even soaking aching body parts. Historical sources indicate that Smardonės Spring has been known for its healing properties since 1587.
Historical and Therapeutic Use
In 1938, with the opening of the Likėnai Sanatorium, Smardonės Spring was used for mineral baths and therapeutic mud preparation, treating various illnesses
before drilling wells were established. The spring's water flowed from the karstic Tatula Formation rocks and was characterized by low overall mineralization, hardness, and sulfate-calcium properties.
Geological Structure and Flow Rate
The diameter of the spring's basin is 15–17 meters, and the banks are silty and covered with turf. In 1961, its flow rate was record-setting at 540 liters per second, making it the most vigorous spring in Lithuania. However, after land reclamation works in 1961, the spring's flow rate decreased to 14 l/s. Currently, the flow rate is not constant, varying from 130 to 540 l/s and can drop to nearly zero during droughts. The spring is also the source of the Smardonės Stream.
The first studies of the Smardonės Spring water composition were conducted by the pioneer of electrochemistry, Theodor Grotthuss, in 1816. His research helped to understand the uniqueness and healing properties of the spring water.