Logo LIFE Logo Natura2000 Logo Ljubljanica Connects Ljubljanica Connects Logo UL FGG Logo KSH

Goals in actions

In 2012, a project was initiated to improve the living conditions of endangered fish species in Ljubljanica. These species are Danube Salmon (Hucho hucho), Danube Roach (Rutilus pigus) and Striped Chub (Leuciscus souffia). The improvement will be achieved by removing the barriers to fish migration to the rehabilitation of fishways. We will aim to improve the water regime and the restoration of aquatic habitats. Furthermore, we will improve the water infrastructure and establish hydrological monitoring to help improve water management. We will restore functionality of the Ljubljanica corridor, connecting two, now unrelated Natura 2000 areas.

On the Ljubljanica, the weir before the railway bridge in Zalog will be sealed, preventing the lowering of water level in the oxbows of Ljubljanica, which will improve the water conditions during dry seasons. The fishways at the dam at the Fužine Castle and the sluice gate at the Ambrose Square will be refurbished and renovated, thereby enabling the migration of fish, which is now disabled. On the Ljubljanica near the Ambrose Square the sluice gate will be renovated by installing a gate valve control. As it is, the chain lock lifting mechanism allows for a rough control of flows and water levels. The upgrading or improvement of the barrier will allow for a more precise regulation of water levels of the Ljubljanica, as well as a better oxygen uptake, especially during low flow and during dry periods. It is vital to maintain an appropriate level of the Ljubljanica, as it affects the entire water regime of the Ljubljana Marshes. The water regime in the Ljubljanica and its tributaries affects the habitats and species included in the Natura 2000 network, but it also affects the activities of fisheries, tourist navigation, drainage of sewerage system, sound agriculture and, eventually, the entire infrastructure. During low water levels of the Ljubljanica, land drainage and hence excessive subsidence of soil occur, deteriorating the living conditions of endangered species and the condition of the entire urban infrastructure of the Ljubljana Marshes.

The project is primarily designed to improve fish habitats, for which specific areas in the Natura 2000 network are designated. In addition, in the project solutions to some other aforementioned activities will be found indirectly.

An integral part of the project is the elaboration of both a hydrological model and a hydraulic model. For the purpose of the project, the models will be adjusted to low flow conditions; however, they will also allow the analysis and operation of flood measures for flood protection, navigation and other provisions on the Ljubljanica.


The project, with a total budget of €1.19 million, is financed by:

Project Coordinator

University of Ljubljana,
Faculty of Civil and Geodetic Engineering

The Faculty of Civil and Geodetic Engineering of the University of Ljubljana is an institution with a tradition. Its study programs in civil engineering, geodesy and water management and municipal engineering are recognized internationally. The basic mission of the Faculty of Civil and Geodetic Engineering UL is undergraduate and postgraduate education of personnel in accordance with the needs of Slovenian construction, geodesy, water management and municipal engineering. Due to the constant changes taking place in our cultural and physical environments, the work of the faculty also focuses on basic, applied and development research from the areas of natural sciences and mathematical sciences, engineering, environmental and social sciences. A special segment of its activities is the transfer of knowledge into practice and professional consulting.

The areas of expertise covered by the Chair of Hydrology and Hydraulic Engineering (KSH) are: hydrology, erosion and sedimentation, water, land drainage, river engineering facilities, use of water power, hydrology and management of natural risks.

As a science, hydrology is part of geophysics; hence, it is included among natural sciences. It deals with the circulation of water in nature; since water engineering facilities serve to regulate the water regime and its exploitation, we must possess a good knowledge of the quantity and quality of water. The tasks of engineering hydrology that are the concern of KSH include the determination of water volume and its quality, identification of the likelihood of their occurrence and impact assessment of buildings and water use to the change of the water regime. In the field of hydrology, KSH in recent years participated in several European projects.

Water science deals with water policy. Given the importance of water for the development and survival of the society, water science is extremely wide ranging and, in addition to technical skills, the basic knowledge of social sciences is required, i.e. in sociology, law, economics and information technology. KSH has made good progress in developing information bases in Slovenia by elaborating the hydrographic coding system.

The area of water management, as an important part of hydraulic engineering, is broad and ranges from the study of the processes of erosion and sedimentation as natural bases of water management, through regulatory methods and dimensioning of water engineering structures, to management of natural hazards, as a socio-economic component, where the participation of stakeholders is important. In the field of urban water management – following intense sediment transport studies in the 1990's and thus contributing to the body of knowledge in the field of fluvial abrasion, and through the development of a patented prototype meter for determination of the dynamic forces on the movement of pebbles in turbulent flows –, KSH's activities shifted into sustainable management of watercourses and the methodology evaluating ecomorphological properties of water bodies.

The areas of water engineering structures and the exploitation of water power deal with the basics of dam engineering and power generation by hydropower plants. The consumption of electricity in Slovenia is increasing with such an intensity that the production capacity hardly meets the increasing demand. Hydropower is one of the most important strategic energy resources in meeting the energy needs in the future.

Today, KSH employs five teachers and one teaching assistant, two young researchers and four full-time professional staff members. In the past KSH offered part time employment to a number of experts in various fields related to hydraulic engineering and hydrology.


GEATEH d.o.o

The GEATEH d.o.o. is a company that is commercially active in the fields of environmental protection, hydropower and urban infrastructure, i.e. from planning to execution, while providing project management services. Today the company employs nine staff members. The key experts are engineers in civil engineering, chemical technology and environmental protection. Due to the wide staffing structure, the company is able to undertake complex consultancy tasks for clients from the industry, local authorities, universities and state.

The Environmental Protection Group of GEATEH provides services related to environmental protection at the operational and strategic levels, the tasks arising from the requirements of applicable environmental and other legislation, while adapting to the requirements and needs of the clients.

Only recently has the company provided services related to hydropower; however, the company human resources and technical support are strong and experienced enough to be able to cope with the most demanding projects. In collaboration with the largest Slovenian companies, such as the HSE Group, and university centres in Slovenia, they are focusing on the siting of hydropower facilities, and the impacts on the environment and the public.

The principal activity of the Municipal Infrastructure Group is to provide the clients and users with comprehensive solutions in municipal collection and treatment of wastewater, drinking water supply and care regarding implementation.


The PURGATOR d.o.o. Company was founded in 2006. The main activity of the company is implementation engineering of wastewater treatment plants (design, construction and management, and other civil engineering works).

The company employs several experts in the fields of engineering, waste water and sewerage. Most of them have international experience.

The PURGATOR d.o.o. also offers the following services:

Steering Commitee

Target species

Hucho hucho L. (Danube Salmon)

Conservation status:

Scientific classification:

The Danube Salmon is the biggest salmonid species in Europe. It is endemic to the Danube basin and inhabits montane and submontane reaches of large streams and swift rivers with gravel beds, well oxygenated, fast flowing water and water temperatures rarely more than 15 °C. It prefers deep pools and shady water under overhanging vegetation. Its body reaches a length of one and a half metre. It has an oblong shape with a very long head and big jaws. Its back and hips are covered with irregularly shaped black spots. This species lives more than 20 years. Males start to reproduce when they reach the age of 3-4 years and weigh 1 kg, while females start at 4–5 years weighing 2–3 kg. Spawning occurs every year in early spring, once the water reaches a temperature of 8–10 °C. Then, adults migrate upriver towards suitable spawning grounds in the upper reaches of the tributaries. Males arrive at spawning sites first. Both sexes excavate a pit about 1.2–3 m in diameter, 10–20 cm deep, and defend a small territory in the spawning grounds against other individuals. The spawning usually takes place at night. During the spawning act, both sexes cover the eggs with substrate. Larvae usually hatch after 25–40 days and stay in the gravel until the yolk sack is absorbed, i.e. after 8–14 days. Juveniles are benthic and inhabit fast flowing waters. Smaller fish feed on the larvae of water insects or on insects dropped into the water, while larger individuals are predators of other species of fish and other small terrestrial vertebrates. Both juveniles and adults are territorial.

The decline of the species was historically caused by overfishing, pollution and dam construction. Currently, the main threats are hydropower plants which heavily regulate the flow regime (impact upon their prey and habitat); the other cause of the decline is, in some countries, pollution (Bosnia and Croatia).

Each year, fish clubs Barje and Vevče introduce 200 Danube Salmons, 30–35 cm long, in the Ljubljanica River, fish club Vrhnika introduces different numbers of Danube Salmon and of different length, while fish club Dolomiti does not stock the Ljubljanica with Danube Salmon.

Rutilus pigus Heckel (Danube Roach)

Conservation status:

Scientific classification:

The Danube Roach is endemic to the Danube basin. In Slovenia, it inhabits the lower reaches of the Drava River, Sava River, Mura River, Krka River, Ljubljanica River and their tributaries. We can find it in streams with slow to moderate water flow and abundant aquatic vegetation, with summer water temperatures between 20 °C and 23 °C. It lives in small groups up to 10 years and grows up to 40 cm in length. The adult body is laterally flat, the body of juveniles is more spindle-shaped. All fins are red, while scales are big and dark bordered. It is a lithophytophilic spawner, which spawns from March to May in the tributaries on gravelly shoals or shallow reaches covered with aquatic vegetation. It feeds on invertebrates, algae and detritus. The population is endangered by river pollution, overfishing and river regulations which result in a stronger river flow and destruction of gravelly areas and spawning places. In the Red List of Fresh Water Fish in Slovenia, it is assigned to the category of endangered (E) species.

Fish clubs Barje, Vevče and Dolomiti do not introduce the Danube Roach in the Ljubljanica River; however, fish club Vrhnika stocks the Ljubljanica with a different number of Danube Roach each year.

Leuciscus souffia Risso (Striped Chub)

Conservation status:

Scientific classification:

Striped Chub inhabits the Mediterranean catchment in the south France, the upper Rhine River basin in Germany (extinct) and Switzerland, the Soča River basin, the Danube River basin – the western tributaries in Germany, Austria, Slovenia, Croatia and part of Bosnia and Herzegovina. It is the smallest representative of genus Leuciscus in Slovenia, with a body length up to 20 cm. Approximately in the middle of the hips it has a wide, dark longitudinal stripe. It prefers the middle reaches of streams and rivers with clear, moderately cold water, moderately swift current and gravel bottom; however, it can be found in most habitats. Striped chub is a gregarious fish species which spawns in March to May in areas with swift, shallow water on gravel beds. Its food consists mainly of aquatic invertebrates from the bottom and water surface, and of epilithic algae. River regulations and water pollution represent a danger for the species. In the Red List of Fresh Water Fish in Slovenia, it is assigned to the category of endangered (E) species.

Fish clubs Barje, Vevče, Dolomiti and Vrhnika do not stock the Ljubljanica River with Striped Chub.

At fish club Barje, the inventory of ichthyofauna in its region is not performed; however, in 2008 an inventory was held in the region of fish club Vevče. Among 172 caught fish there were 11 Danube Salmons, 18 Danube Roaches and one Striped Chub. According to an oral source, 10 striped chubs, 5–6 Danube Salmons and no Danube Roaches were caught among 200 caught fish in the space of 300 m in the region of fish club Dolomiti.