Case study:LIFE 06 NAT/SLO/000069 Intermittent Lake Cerknica
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Project overview
Status | Complete |
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Project web site | |
Themes | |
Country | Slovenia |
Main contact forename | Tanja |
Main contact surname | Vasilevska |
Main contact user ID | |
Contact organisation | Notranjski regijski park |
Contact organisation web site | |
Partner organisations | |
This is a parent project encompassing the following projects |
RESTORATION OF THE GORIŠKI BREŽIČEK STREAM, RESTORATION OF THE TRESENEC STREAM |
Project summary
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.
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.
Monitoring surveys and results
Lessons learnt
Catchment and subcatchment
Edit the catchment and subcatchment details
(affects all case studies in this subcatchment)
Catchment
River basin district | Danube River Basin District |
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River basin | Danube |
Subcatchment
River name | Sava River |
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Area category | 100 - 1000 km² |
Area (km2) | |
Maximum altitude category | 200 - 500 m |
Maximum altitude (m) | 270270 m <br />0.27 km <br />27,000 cm <br /> |
Dominant geology | |
Ecoregion | Dinaric Western Balkan |
Dominant land cover | Wetland |
Waterbody ID |
Other case studies in this subcatchment: HPP Blanca
Site
Name | |
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WFD water body codes | |
WFD (national) typology | |
WFD water body name | |
Pre-project morphology | SI141VT2 VTJ Cerkniško jezero (Cerknica lake), Straight |
Reference morphology | Sinuous |
Desired post project morphology | |
Heavily modified water body | |
National/international site designation | |
Local/regional site designations | No, Ramsar, Special Protection Area |
Protected species present | |
Invasive species present | |
Species of interest | |
Dominant hydrology | Ephemeral, Quick run-off, we need to check |
Dominant substrate | Silt |
River corridor land use | Wetland, Extensive agriculture, Grassland, Woodland |
Average bankfull channel width category | |
Average bankfull channel width (m) | |
Average bankfull channel depth category | |
Average bankfull channel depth (m) | |
Mean discharge category | |
Mean annual discharge (m3/s) | |
Average channel gradient category | |
Average channel gradient | |
Average unit stream power (W/m2) |
Project background
Reach length directly affected (m) | |
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Project started | January/01/01 |
Works started | |
Works completed | December/01/01 |
Project completed | |
Total cost category | 2009 k€"2009 k€" is not in the list (Less than 1 k€, 1 - 10 k€, 10 - 50 k€, 50 - 100 k€, 100 - 500 k€, 500 - 1000 k€, 1000 - 5000 k€, 5000 - 10000 k€, more than 10000 k€) of allowed values for the "Total cost category" property. |
Total cost (k€) | 1000 - 5000 k€"-5000k€" is not declared as a valid unit of measurement for this property. |
Benefit to cost ratio | |
Funding sources | 1840 |
Cost for project phases
Phase | cost category | cost exact (k€) | Lead organisation | Contact forename | Contact surname |
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Investigation and design | Ministry of Environment and Spatial Planning k€"Ministry of Environment and Spatial Planning k€" is not in the list (Less than 1 k€, 1 - 10 k€, 10 - 50 k€, 50 - 100 k€, 100 - 500 k€, 500 - 1000 k€, 1000 - 5000 k€, 5000 - 10000 k€, more than 10000 k€) of allowed values for the "Investigation and design cost category" property. | ||||
Stakeholder engagement and communication | |||||
Works and works supervision | |||||
Post-project management and maintenance | |||||
Monitoring |
Reasons for river restoration
Mitigation of a pressure | |
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Hydromorphology | |
Biology | Quantity & dynamics of flow, Channel pattern/planform, Structure & condition of riparian zones |
Physico-chemical | |
Other reasons for the project |
Measures
Structural measures
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Bank/bed modifications | changed bank slope |
Floodplain / River corridor | local deepenings, construction of small wooden weir to prevent uncontrolled deepening, coves and bays construction, construction of the overflows between individual meanders |
Planform / Channel pattern | retention of water in depressions and stream branches, ground water level rise, slower runoff of low waters |
Other | re-instatement of old course; |
Non-structural measures
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Management interventions | late mowing and mulching on the permanently protected land, mapping of habitat types |
Social measures (incl. engagement) | |
Other | popularization of the project, Information provision, education of the youth on the importance of nature conservation |
Monitoring
Hydromorphological quality elements
Element | When monitored | Type of monitoring | Control site used | Result | ||
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Before measures | After measures | Qualitative | Quantitative | |||
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Biological quality elements
Element | When monitored | Type of monitoring | Control site used | Result | ||
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Before measures | After measures | Qualitative | Quantitative | |||
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Physico-chemical quality elements
Element | When monitored | Type of monitoring | Control site used | Result | ||
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Before measures | After measures | Qualitative | Quantitative | |||
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Any other monitoring, e.g. social, economic
Element | When monitored | Type of monitoring | Control site used | Result | ||
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Before measures | After measures | Qualitative | Quantitative | |||
Monitoring documents
Image gallery
Additional documents and videos
Additional links and references
Link | Description |
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Supplementary Information
Edit Supplementary Information
REFERENCES
LAYMAN’S REPORT Project LIFE 06 NAT/SLO/000069, Intermittent Lake Cerknica, Notranjska Regional Park, Cerknica, december 2009.
Smolar-Žvanut N., Fazarinc R., Perič B., Blumauer S., Kavčič I. 2011. The restoration of tributaries of Cerknica Lake and Škocjan Caves Park.