Unique lake Boksitogorsky district, Leningrad region
The supply of fresh water Petrodvorets, Lomonosov, the red Village is due to extraction of groundwater. In particular, Krasnoselskii water system water is supplied from captaia, created on the basis of deposits of fissure-karst waters. On the fissure-karst aquifers the drilling of wells. and water features a good quality. Deposits of karst rocks in the Leningrad region found extremely small, but in Boksitogorsk district of the nature of karst is manifested in all its glory.
On the border of Leningrad and Novgorod areas there are lakes and streams, United in Spirovska water system length of approximately ten kilometers. Lakes and rivers have karst origin that makes them exceptional properties, namely, periodic disappearance, when the waters suddenly disappear with all its inhabitants, and then just as suddenly re-emerge.
Spirovska lake is not too deep and are renowned for with numerous bays and tributary waters in the rivers and rukako. The lakes are replenished with water mainly due to numerous natural springs. Every 5-7 years is incredible: water from lakes goes underground through sinkholes large diameter — one of which reaches 40 meters in diameter. The water noise is drawn into the mouth, literally a week later, the lake dries up, and it is possible to move on motorcycles and carts with yoked horses in them.
Then in six months, sometimes a year, the water begins to back into the water. Scientists still can’t answer the questions: where is hiding a huge amount of water, where she kept all this time, and how the process of her return to the lake, along with the entire population of fish.
Vanishing river Ragusha
In Boksitogorsk area three karst river — Cutting, Leninka and the Ragusha. Last declared a natural monument and is considered one of the most famous rivers among vanishing. The Ragusha river has a meandering channel running through alternating flat areas and canyons with waterfalls. Altitude rocky canyons up to 50 meters.
In one place the Ragusha dives into swallow holes and continues its way under the ground, so after a mile out from the ground and again flow by filling with water a traditional terrestrial channel. The Ragusha river can be called a natural landmark of global significance. Because endangered rivers to the plains of the Leningrad region non-specific phenomenon, as indeed for other parts of the globe. And considering choicesexy the river is very close to disappearing lakes, the uniqueness of the natural water body Boksitogorsky district can be considered conclusive.