Small Hydro Plant Litoměřice – securing a foundation pit in the Artesian pressure water environment

A new Small Hydro Plant Litoměřice on the Labe River is currently under construction on the right riverbank of the weir in České Kopisty. With its planned output of 7,2 MW it should become one of the largest low-head small hydro plants in the Czech Republic. Securing th e plant foundation pit was designed with the use of common special foundation technologies, such as diaphragms, sheet piles and pile walls. However, in course of carrying out the diaphragm walls Artesian water pressure of a delivery head of approx. 2–3 m above the ground was encountered and this situation had a major influence on further development of foundation works on the lower structure. The modifications also concerned carrying out the already designed technologies and the foundation pit bottom stability had to be strengthened by grouting in the rock massif as well as relief boring to prevent pressure water breakthrough.