Case study:LIFE 06 NAT/SLO/000069 Intermittent Lake Cerknica
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- 1 Project overview
- 2 Image gallery
- 3 Catchment and subcatchment
- 4 Site
- 5 Project background
- 6 Reasons for river restoration
- 7 Measures
- 8 Monitoring
- 9 Additional documents and videos
- 10 Additional links and references
- 11 Supplementary Information
|Project web site||http://life.notranjski-park.si/eng/index.shtml|
|Themes||Habitat and biodiversity, Hydromorphology, Land use management - agriculture|
|Main contact forename||Tanja|
|Main contact surname||Vasilevska|
|Main contact user ID|
|Contact organisation||Notranjski regijski park|
|Contact organisation web site||http://life.notranjski-park.si/eng/index.shtml|
| This is a parent project
encompassing the following
|RESTORATION OF THE GORIŠKI BREŽIČEK STREAM, RESTORATION OF THE TRESENEC STREAM|
In 2006 Notranjska Regional Park acquired financial support from European programme LIFE – Nature for project LIFE 06. The purpose of this project was the establishment of appropriate conditions for protection and conservation of animal and plant species and their habitats on Lake Cerknica. Factors that threaten the biodiversity on Lake Cerknica are modified watercourses, abandoning of meadow mowing and deficient knowledge of nature and its conservation.
With the intention of maintaining biodiversity on Lake Cerknica efforts were oriented to following actions:
- Restoration of watercourses, that would contribute to higher water ground level and retaining of overall water level on Lake Cerknica
- Composition of a Management plan, which serves as groundwork for managing the project area and is orientated towards conservation of natural and cultural heritage of Lake Cerknica
- Mapping of habitat types with the intention of conserving the endangered ones
- Land managing including buying, late mowing and mulching on the permanently protected land.
- Popularization of the project and education of the youth on the importance of nature conservation.
The aim of the project was the restoration of former meanders and by doing so retaining the water longer in the dry period and increasing the groundwater level in wetland areas. It was expected that in this way the ecological conditions of the wetland areas, and thereby the living conditions for flora and fauna, improve. Inženiring za vode d.o.o. produced the project documentation, based on a review of the situation on the terrain and examining the location of riverbeds as they were before the regulating operations began. More than 12 km of watercourses in the Cerknica area are included in this study.
Re-instatement of the old course and creation of backwater and water retention areas to encourage groundwater level rise and slower runoff of low waters.
Community Involvement - education of the youth on the importance of nature conservation.
RESTORATION OF THE GORIŠKI BREŽIČEK STREAM:
By restoring former meanders of the Goriški Brežiček stream it was intend to raise the groundwater level in the area of the Dujce fen which ranks among the qualifying habitats for determining the Natura 2000 areas, and thus restore appropriate conditions for sustaining this bog. The company TGM Bizjak, Dušan Bizjak s.p. completed the restoration works on approximately 500 m long section of upper stream and on 200 m in its lower part at the confluence with the Lipsenjščica stream.
Expected results of this restoration:
- slower runoff of low waters from the area of the intermittent lake,
- ground water level rise,
- retention of water in depressions and stream branches, consequently higher constant ground water level height and change in the soil – water rate.
Restoring Goriški Brežiček stream was planned for the entire section, from the mill at the source, to its mouth in Lipsenjščica River, but only a part has been realized. The entire length of the stream has been straightened in the past, but given the terrain and vegetation, the original stream channel is still clearly visible. Restoring the original layout consisted of its deepening. Average width of the planned channel section was from 3.0 to 6.0 m. Excavation has been exercised in the form of U, with banks sloping 1:2, but it was planned that the transition slope of stream bank and terrain on majority of the length is carried out in a vertical slope and then let the water itself create a stable bank. It was assumed that the stability would be provided primarily by turf and partly by the riparian vegetation root system. Deepening of the stream bed at the juncture with the primary bottom at the upstream side has been protected by the small wooden weir (a small weir with the top corners at the bed level or just above it, which is not noticeable under normal hydrological conditions). Where possible, multiple channels with lower spills/overflows between the excavated meanders were predicted. Spills/overflows has been fortified with small wooden weirs (wooden piles, tree trunks) to prevent uncontrolled deepening of the spills/overflows. Spills/overflows were carried out above medium water level and they were covered with turf. At the appropriate locations at the contact of the current and planned section have also been carried out coves or bays, which are designed by keeping part of the current channel or in the area of inactive tributaries.
RESTORATION OF THE TRESENEC STREAM:
The restoration of the former riverbed of Tresenec stream from its source in the direction of Levišča sinkholes was undertook in order to raise the level of groundwater and thus enable the sustenance of characteristic water and river-bank plant communities. The Tresenec stream is also of great importance to the animal world since it is the only watercourse in the Lake Cerknica area that never runs dry and as such offers refuge for the water animals in the times of drought. On its banks you can still find elusive Otter’s (Lutra lutra) footprints. GRADBINKO d.o.o. enterprise completed the restoration on 650 m long section of the Tresenec stream.
By increasing length of stream, restoring former branches and meanders, the water surface of the stream increased, which will have a positive effect on the conservation of aquatic, riparian and wetland habitats.
Monitoring surveys and results
Catchment and subcatchment
Select a catchment/subcatchment
Other case studies in this subcatchment: HPP Blanca
Cost for project phases
Reasons for river restoration
Hydromorphological quality elements
Biological quality elements
Physico-chemical quality elements
Additional documents and videos
LAYMAN’S REPORT Project LIFE 06 NAT/SLO/000069, Intermittent Lake Cerknica, Notranjska Regional Park, Cerknica, december 2009. Availabe at: http://ec.europa.eu/environment/life/project/Projects/index.cfm?fuseaction=home.showFile&rep=file&fil=LIFE06_NAT_SI_000069_LAYMAN.pdf
Smolar-Žvanut N., Fazarinc R., Perič B., Blumauer S., Kavčič I. 2011. The restoration of tributaries of Cerknica Lake and Škocjan Caves Park. Seminar: Forging Targets and Solutions for Rivers and Water Ecosystem Restoration. Ljubljana, 16-18 November 2011.