The Application of the Shorezone Functionality Index on Italian, Austrian and Slovenian Lakes Within the SILMAS Project International Working Group

The application of the Shorezone Functionality index on Italian, Austrian and Slovenian lakes within the SILMAS project International working group

Maurizio Siligardi, Barbara Zennaro (Agenzia provinciale per la protezione dell’ambiente) Rossano Bolpagni (università di Parma, Regione Lombardia) Roswitha Fresner, Michael Schönhuber (Carinthian Institute for Lake Research) Liselotte Schulz (Government of Carinthia, Dep. 8 – Environment) Tina Leskosek (National Institute of Biology, Slovenia)

Coordination Maurizio Siligardi, Barbara Zennaro (Agenzia provinciale per la protezione dell’ambiente).

Authors

Maurizio Siligardi, Barbara Zennaro (Agenzia provinciale per la protezione dell’ambiente). Rossano Bolpagni (Università di Parma, Regione Lombardia) Michael Schönhuber (Carinthian Institute for Lake Research) Tina Leskosek, Irena Bertoncelj, Uros Zibrat, (National Institute of Biology, Slovenia)

Acknowledgement Special thanks from APPA to all those that hosted and participated to the SFI trainings during summer 2012 and all those that supported the working group to carry on the work.

APPA non è responsabile per l’uso che può essere fatto delle informazioni contenute in questo documento. La riproduzione è autorizzata citando la fonte.

2 Summary

1. The SILMAS project...... 4

2. The importance of the lake shorezone...... 6

3. The Shorezone Functionality Index...... 8

4. The Shorezone Functionality Index as a management tool...... 12

5. The application within the SILMAS European Project...... 14

6. SILMAS Lake Reports...... 16

Levico Lake...... 17 Caldonazzo Lake...... 21 Idro Lake...... 26 Wörthersee...... 28 Millstätter See...... 31 Lake Bohinj...... 34

3 1. The SILMAS project

4 The Alpine lakes share a common identity, rooted in their geographical location and the cultural and economic benefits they generate. Given how difficult it is to reconcile environmental protection and human activity, lake managers (elected representatives, government bodies and local associations) decided to pool their experience to solve the problems they all faced. To this end, five countries - France, Italy, Slovenia, Germany and Austria (figure 1) - formed a network of Alpine lakes. Launched for a three-year period (2009/2012) as part of European territorial cooperation, SILMAS (Sustainable Instruments for Lake Management in the Alpine Space) is a major project aimed at pooling experience and know-how in sustainable Alpine lake management. SILMAS follows on from Alplakes, an earlier network of Alpine lakes. SILMAS objectives are • Share ideas and experience across a European network • Produce concrete tools (technical guides, training programmes, educational games) to help Alpine lake managers protect their resources • Raise public awareness of the need to protect and sustainably manage this fragile environment SILMAS work priorities are • The probable effects of climate change on the Alpine lakes, and how to tackle them • Managing water usage conflicts • Educating the public in sustainable development as it relates to the Alpine lakes

Figure 1> Countries participating to the SILMAS project.

5 2. The importance of the lake shorezone

6 While most of earlier indices were characterized by a particular analysis, for example to the water itself (chemical analyses) or to the biotic environment (biological extended index), the lake Shorezone Functionality Index (SFI) looks at the overall status of the lacustral environment and assists in the identification of the causes of deterioration, zooming out from the waterbody itself to also include all the surrounding territory and watershed topography.

The area around the shores is a transition zone (ecotone) By “shorezone”, it is meant that area that includes the littoral between the surrounding territory and the lake and guarantees (maximum depth of 1 meter) and the riparian zones, and it the execution of the ecological processes needed to protect extends inland up to 50 meters from the shoreline (with the the lake from the wateshed’s no-point sources of pollution. Its exception of interruptions or particular lake morphology which structure and the extension are influenced by the topography, may limit its width) (figure 2). the climate and the soil’s geological composition, while its water fluxes, the nutrients and sediment inputs, and the diffusion of animal and plant species are influenced by the lake riparian vegetation.

Figure 2> Structure of the lake shorezone.

The riparian zone, the area immediately adjacent to a body An healthy littoral zone (the first meters from the shoreline into of water functioning as a transition between the lake and the the water) also provides habitat, food and nesting materials for surrounding territory, is important as it regulates inputs (nutrients aquatic and terrestrial animals, it is important for nutrient cycling and sediments), improving the lake water quality by filtering the and also protects the shoreline from erosion, favoring a good runoff from the catchment area and removing pollutants (the water clarity (through reduced wave action). vegetation in the riparian zone can remove up to 90% of the By “Lake Shorezone Functionality” it is meant the capacity to nutrients passing through) and by aiding sedimentation (the accomplish those determinate functions. vegetation slows the water flowing into the lake); it also provides habitat to aquatic and terrestrial animals, including food, shade (temperature control), shelters, areas for hunting and breeding; moreover it protects the shoreline from erosion, favoring the bank stabilization.

7 3. The Shorezone Functionality Index

8 The importance of understanding and evaluating the lake shorezone functionality lead to the creation of a new system of indicators that could evaluate the shorezone functionality. The Shorezone Functionality Index was developed in Italy in 2004 by the National Environmental Protection Agency (APAT, now ISPRA)’s working group, coordinated by the Provincial Environmental Protection Agency (APPA) of Trento. It was created as the twin brother of the already existing Fluvial Functionality Index (2000) and tailored to the reality of the Alpine lakes.

It was later integrated within the AlpLakes European Project for shore that has similar ecological, morphological and functional the lakes in region Lombardy (Italy), within the Silmas European characteristics and can be therefore described in a single form. project for the lakes along the alpine arch (Italy, Austria and Every time there is a change in one or more parameters (for Slovenia), within the Eulakes European Project modified for the example artificialization, shore zone width or composition), a big lakes of central Europe (Italy, Austria, Poland and Hungary) new form is used to describe the next homogeneous shorezone and finally ran in the lakes of by Aracaunia (Chile), by the stretch. University of Villarica, for the Chilean Environmental Agency. Different parameters are surveyed and evaluated in the field with Both biotic and abiotic factors are used to evaluate the buffering an ecological point of view. They include ecological parameters capacity of riparian vegetation, the complexity and artificiality of (typology, width, continuity or interruption of the riparian the shoreline, the anthropogenic use of the surrounding territory, vegetation), socio-economic parameters (land use, presence and the way the inputs enter the water body from the watershed. of infrastructure…) and other general parameters (steepness, concaveness, shore artificiality…). The SFI application consists in filling out two forms: the first form collects general information about the lake and its watershed Each surveyed parameter has its own numeric weight, and a (topography, morphology, climate…); the second form is filled dedicated software (SFINX02) runs the parameter collected out for each homogeneous shorezone stretch identified in the for each homogeneous stretch through a classification tree field. The “homogeneous shorezone stretch” is a stretch of (figure 3) that will lead to different functionality levels.

9 visuel italien

Figure 3> The classification tree in the SFI software.

10 During the phase of the index development, nine parameters were identified, through a neural network analysis, as the ones influencing the most the shore functionality (figure 4). There parameters are: • Shore artificiality • Presence of grass • Interruption of the lake-shore-zone • The presence of road Infrastructure • The concavity of the shore profile • The presence of reeds • The presence of arboreal species • The heterogeneity of arboreal vegetation • The presence of non-hygrophilous species Figure 4> Example of results from an homogeneous stretch in SFINX02. Each node of the classification tree shows the probability of each homogeneous stretch to fall into one of the five categories (as LEVEL JUDGMENT COLOR suggested from the WFD 2000/60/CE), ranging from I - Excellent I Excellent BLUE to V - Bad). The higher percentage will determine the level of II Good GREEN functionality (table 1). III Moderate YELLOW The results and parameters are then transferred into a GIS IV Poor ORANGE platform in order to create thematic maps of the parameters V Bad RED surveyed and to be able to carry out spatial analysis. The SFI maps are very important as they provide a first direct sight of Tab. 1> Functionality levels, relative judgments and reference colors. the general status of the lake shorezone (figure 5), for example indicating the location of remaining areas of high functionality (blue colour). The length of each homogeneous stretch, and therefore the total lake perimeter length for each category, can also be calculated in a GIS. It is also possible to create different thematic map showing the different parameters (figure 6), for example the shorezone artificiality or the presence of exotic species. Different layers, such as the surveyed parameters, the soil use, the presence of houses, presence of waste water collectors etc., can be overlaid to carry out spatial analysis and identify the weaker or stronger locations, areas more in need or more prone to restoration actions. Figure 5> Shorezone Functionality Index for Caldonazzo lake. The map provides a first direct insight on the status of the lake. It is important to keep in mind that shore “naturality” and “functionality” are two different concepts. In fact, even if totally natural, a shore may have low levels of functionality in specific cases: for example, steep cliff falling directly into the lake with no or little riparian vegetation are in fact not able to carry out any good ecological function.

Figure 6> Thematic maps for Caldonazzo lake showing the with (“ampiezza”) of the shorezine (red = 0 meters, green = more then 40 m), and the artificiality (“artificialità”) of the shorezone (red = 100% artificial, blue = natural shore).

11 4. The Shorezone Functionality Index as a management tool

12 The potential of the SFI method lies in the ability of obtaining a synthetic value of lake shorezone functionality. The SFI approach permits to complete the study of the internal lake’s dynamics, often modified for production or recreational-tourism purposes. A lake’ shorezone management based on the concepts of its functionality allows to reconcile the environment protection with the human use of the lake, helping an eco-sustainable city planning and watershed management. Lake managers and stakeholders can use these results for a sustainable ecosystem-based watershed management.

The results obtained provide, relatively economically and in understand the results. It highlights the shorezone weakness and short period of time, an immediate general picture of the state of strengths and include specific indications of actions needed to the shores around the lakes, in opposition of earlier indices that improve the lake functionality. The report includes the following were representative only of specific points along the shore. The chapters: results can also be used to easily identify the location and the • Introduction to the Shorezone Functionality index actions needed in potential restoration sites (different scenarios • Lake’s location, origin and history can be modeled in a specific area with SFINX02 changing • Results, statistical analysis and management recommendations determinate parameters to foresee the impacts that public or • Application of the Shorezone Functionality Index (description private work may have on the waterbody), location of protected of each homogeneous stretch one by one, with photos, SFI areas, location of areas of important economic value and so on. result and specific recommendation when applicable) SFI answers to the current needs, as requested by the 2000/60/ The SFI thematic maps can be created for each parameters CE directive, to develop new indices able to assess the hydro- collected in the field. A shapefile containing this information morphologic elements of the lake’s ecosystems, including the is created for each lake and for each SFI study. Importing the riparian zone. results into a GIS environment allows to carry out geospatial and geostatistical analysis. For example, SFI studies carried out in Future SFI reports in the same lake can also be used to track a specific lake in 2 different years can be overlapped to extract changes along the shorezone throughout time. information on changes in the shore functionality throughout Different output formats within this project are created to reach time. the final users, may they be managers, locals stakeholders or The SFI brochure was studied to share the results with a general tourists. The outputs include the SFI report, the SFI thematic public and it is usually available in both English and the local maps and the SFI brochure. language. The brochure describes shortly the methodology, the The SFI report describes the lake and all the homogeneous lake main categories, a summary of the statistical results and stretches identified, and is written so that the reader, not management suggestions. necessarily familiar with the index or the lake, will be able to

13 5. The application within the SILMAS European Project

14 Within the SILMAS European Project, Italy, Austria and Slovenia cooperated together in applying the Shorezone Functionality Index on their project lakes. The Shorezone Functionality Index (SFI) is an index that evaluates the capacity of the area located just adjacent the lake shore to accomplish determinate ecological functions, such as the purification of waters coming from the surrounding watershed and their capacity to host aquatic animals.

The SFI reports give specific indications on what actions are research (Slovenia), and the Department of Environment of the needed to improve the functionality of the shorezone and can Regional Government of Carinthia (Austria). These 3 entities therefore be used to plan, monitor and evaluate restoration subsequently and autonomously carried out the index on their efforts. Similarly, different scenarios can be modeled in a specific own lakes, providing as well useful feedback to further improve area to foresee the impacts that public or private work may have the index. on the waterbody. The data can be entered into a GIS system, The first results and the comments collected by the partners lead in order to carry out further spatial analysis and easily display in fact to the update of the SFI software SFINX into the newer the results in maps. For these reasons, this index represents an version SFINX02, corrected for some bugs and graphically important and powerful tool that can be used for sustainable improved. planning and management. As a project output, 6 lakes have been surveys the SFI index Between summer 2010 and 2011, APPA offered different (table 2), their location shown in figure 7. The following chapter seminars on SFI methodology and implementation to 3 Silmas’s shows an extraction of the SFI report (chapter 2 and chapter 3) project partners: Region Lombardy in collaboration with including indication on where to find the full report and more University of Parma for lake Idro (Italy), the National Institute of information about the index. Biology - Department for freshwater and terrestrial ecosystem

Country Lake Partner Contact Person IT Caldonazzo APPA Barbara Zennaro IT Levico APPA Barbara Zennaro IT Idro Reg. Lombardia Rossano Bolpagni AT Millstätter See ABT 8 Michael Schönhuber AT Wörthersee ABT 8 Michael Schönhuber SL Bohinj NIB Tina Leskosek

Table 2: Lakes participating to the SFI surveys.

Figure 7> Location of the SFI/SILMAS lakes.

15 6. SILMAS Lake Reports

16 Levico Lake

Location and Origin

Levico lake is located in the Province of Trentino, Italy (figure 8), close to the homonymous touristy town of Levico (population = 7.300) which is located on the southern-eastern section of the lake (figure 9 and 10).

Figures 8, 9, 10> Location of Levico and Caldonazzo lakes, delineation of their watersheds and satellite images of Levico’s surrounding territory.

The lake is located 400 meters a.s.l, and its shape reminds of a The surrounding territory is mainly characterized by coniferous Norwegian fjord. It was originated, similarly as the neighboring forest running all the way to the water, some agricultural fields Caldonazzo lake located on the other side of Tenno’s hills, by an and the developed area of the Levico town (figure 10). alluvional damming created by Rio Maggiore. The tributaries are Field work in Levico lake was carried out by Maurizio Siligardi and the Visintainer and the Rio Maggiore streams. Its only emissary Barbara Zennaro, from the Settore informazione e monitoraggi of joins the waters coming from Caldonazzo lake few hundreds the Environmental Protection Agency of the Province of Trento, meter downhill, forming the springs of the Brenta river. The on the 29th September 2010. transparency (Secchi disk) is about 5 meters (7,6 m in winter) and the lake water have a deep blue color. Its extension is big enough to mitigate the surrounding climate, and its shores host two beaches with a park and a camping, all of them very frequented during the summer season.

Results

In Levico lake, most of the shorezone shows an excellent to good functionality (figure 11), with homogeneous stretches able to carry out different ecological functions, such as nutrient removal from surface water running into the lake, shore erosion protection, providing habitat for aquatic and terrestrial species.

Figure 11> SFI results for Levico Lake.

17 Lower values are generally due to the presence of exotic species, lack of hygrophilous species and an increasing level on human pressure. On 6 individuated homogeneous stretches, more then ¾ felt under the excellent and good category (83%) and were characterized by a shorezone composed by green forests, partly BASSE penalized by the presence of exotic species and no-hygrophilous species (figure 12). The remaining two stretches felt under the categories moderate and poor (17%) and are represented by the DEF camping (that obtained a better result compared to the public beach thanks to the presence of the reeds and different arboreal riparian species) and the public beach.

Figure 12> Percentage distribution of the functionality level of Levico Lake. Stretches SFI Value Total m Percentages identified Excellent 3 1368 21% Good 1 3970 62% Moderate 1 350 5% Poor 0 0 0% Bad 1 790 12% TOTAL 6 6478 100%

Table 3> Results for Levico Lake: along Levico’s perimeter, 6 homogeneous stretches were identified, for a total of 6,5 km of lake perimeter.

SFI Category 1 and 2

These categories occupy most of the lake perimeter, and are The second identified pristine stretch is the protected biotope characterized by steep hills covered predominantly with dense hosting reeds (instituted by the Province of Trento in 1988 and native vegetation mainly no-hygrpphylous that growth without 1994) located on the southern end of the lake (figure 15). The interruption growing until the lake shore (figure 13). Paths or territory surrounding this stretch is poor in vegetation, composed accesses to the shore are absent in the western part of the mainly by shrubs and small trees and it is partly urbanized. lake, while a small fisherman path reaches the emissary on the The third identified pristine stretch encloses the small area northern side of the lake (figure 14). surrounding the Brenta emissary. This area is characterized by The shorezone should be able to filter any cause of no-point- the presence of older trees on the left side of the emissary, and source of pollution (and storm water run-off), despite of the of a man-made area of the right side. steepness of the area and the surrounding environment (0-200 meters from the coast) and the penalization due to the presence of exotic species (such as robinia) and no-hygrophilous species.

Figures 13, 14> Examples of categories 1 and 2.

18 Figure 15> Examples of categories 1 and 2.

SFI Category 3 and 5

The low SFI result is mainly due to the high artificiality of the The presence of bare soil and the high population density during shore and the lack of riparian vegetation: superficial waters and the tourism season, make this stretch very sensitive to pollution possible no-point source pollutant can flow directly into the lake issues. in this area without encountering any particular barrier. The two stretches falling into this category are the artificial public beach, composed by shingles and cobbles (figure 16), and a private camping site, composed by bare soil slightly covered by small trees planted probably for shading. There are small pools of wet reeds and few riparian trees, which are separated from the land by an impermeable sustaining wall.

Figure 16> Example of SFI category 5.

19 Lake Levico Management Recommendatio

Levico lake is generally an healthy lake suffering from a Other recommendation is the frequent control of the quality seasonal human impact during the summer months. Definitely of main tributaries to avoid discharge of nutrient from the the presence of woods around the lake protects it by possible surrounding environment. source of pollution that may come from the cultivation in Tenna’s It is also recommended to promote lake environmental education, hill (on the western site). such as sensitization campaigns for local stakeholders and Levico Lake does not present any particular issue regarding managers on the role of the lake and classes on lake ecology for water quality and no particular management actions are schools, maybe using the concept of the “house on the lake”, as suggested for the management of this lake. proposed in the SILMAS project. The stretch with the artificial beach could be improved by replacing the broken impermeable wall with a permeable one, constructed with woods and rocks, allowing the growth of the reeds in certain spots, also to ensure an healthy habitat and a safe corridor for aquatic animals.

Authors

Barbara Zennaro, Maurizio Siligardi Agenzia provinciale per la protezione dell’ambiente Settore informazione e monitoraggi Piazza Vittoria, 5 - 38122 Trento Tel. 0461 49 77 39 - Fax 0461 49 77 69 [email protected] [email protected]

For more information

Agenzia provinciale per la protezione dell’ambiente Settore informazione e monitoraggi Piazza Vittoria, 5 - 38122 Trento Tel. 0461 49 77 39 - Fax 0461 49 77 69 [email protected] [email protected] www.appa.provincia.tn.it

Full report available at

http://www.appa.provincia.tn.it/appa/pubblicazioni/-Acqua/

20 Caldonazzo Lake

Location and Origin

Caldonazzo lake is located in the Province of Trentino (Italy), close to the town of Pergine (population =20.580) which is located on north section of the lake (figure 17, 18, 19).

BASSE DEF

Figures 17, 18, 19> Location of Levico and Caldonazzo lakes, delineation of their watersheds and satellite images of Caldonazzo lake’s the surrounding territory.

Caldonazzo lake is the first natural lake for extension entirely The lake was originated, similarly as the neighboring Levico located in Trentino. Its extension is big enough to mitigate the lake located on the other side of Tenno’s hills, by an alluvional surrounding climate: Caldonazzo means “warm”: even if it dam created by the old course of Fersina river and by the Rio is an alpine lake, it is very popular for bathing, as its average Mandola. temperature in summer months - June 20°C, July 23°C, August The main tributary is the Rio Mandola stream, complemented 24°C - is perfect for a refreshing bath and to practise water by other little streams around the lake (Fos dei Gamberi, Fos dei sports. Lavatoi, Rio da Ischia). Its only emissary, on the eastern side of The lake is located in the district C4, High Valsugana, and is the lake, joins the waters coming from Levico lake few hundreds divided into 5 municipalities: Pergine, which occupies the larger meter downhill, representing the springs of the Brenta river. area, Calceranica, Caldonazzo, Bosentino and Tenna. Field work in Caldonazzo lake was carried out in different The State Road 47 Valsugana runs along the eastern dates by foot and by boat. The following table summarizes the embankment of the lake, but its impact is often mitigated by field work date and surveyors, from the Settore informazione the presence of various tunnels. This road connects the capital e monitoraggi of the Environmental Protection Agency of the city of Trento with the Veneto Flat and then Padova and Venice, Province of Trento. crossing all Valsugana Valley. Along the western embankment of the lake instead, often limiting the width of the shorezone, there are the main road connecting Pergine with Calceranica, the Valsugana Railway and the pedestrian/bicycle track, all running parallel to each other.

Date Surveyors

16 June 2010, Maurizio Siligardi, Barbara Zennaro, by feet Catia Monauni, Renato Grazzi

12 October 2010, Maurizio Siligardi, Barbara Zennaro, by boat Renato Grazzi

12 April 2012, Barbara Zennaro, Gaetano Patti, Renato Grazzi by boat

21 Results

The lake was strongly eutrophic during the 70’s and its The positive effects of these actions were already visible after environmental conditions were low: the water had a low only 3 years, but it took the lake 35 years to restored the trophic transparency value (Secchi Disk’s value of 80 cm), high condition needed for the tourist industry. chlorophyll and nutrient content. Given the tourist value of the lake, the provincial authorities decided to act on different The shore generally shows an high level of artificiality, with restoration actions, consisting of: only few places left pristine (figure 20). Extended reeds belts 1. A collection system was built to collect all urban wastewater are present only in the northern side of the lake, where they existing along the lake constitute the protected biotope (instituted by the Province 2. The deep water was oxygenated with a Swedish method, since 1988 and 1994) and in the southern end, where the lake consisting of big bells located at a depth of 12 meters blowing waters exit to form the Brenta river. compressed water. The air mixed with the water and was The two main roads running north to south along the eastern distributed in a radial way in the lake. To date, the bells are and western shores of the lake often represent a limitation of the still in part functioning shore width, with the exception of those areas (in the eastern 3. The deep water was also removed with a siphon located close side), where the tunnels allow a continuity of vegetation from the to the Brenta emissary shore to the surrounding environment. 4. The remaining pristine shorezones were protected.

Figure 20> SFI results for Caldonazzo Lake.

Stretches SFI Value Total m Percentages identified Excellent 6 2346 19% Good 4 1198 10% Moderate 4 3041 25% Poor 1 238 2% Bad 14 5494 44% TOTAL 29 12317 100%

Table 4: Results for Caldonazzo Lake: 29 homogeneous stretches were identified, for a total of 12.3 km of lake perimeter

22 On 29 individuated homogeneous stretches, nearly half (44%) shows a Bad value. These are the stretches with beaches and cemented sustaining walls built right on the water-land interface. The second bigger class is Moderate (25%), and represents BASSE stretches with a restricted shorezone width which although still hosts vegetation. The remaining classes, Good (10%) and Excellent (19%) are represented by those areas where the reeds is present and where the road tunnels allow a continuum DEF between the shore and the surrounding environment, increasing the functional shorezone width (figure 22).

Figure 22> Percentage distribution of the functionality level of Caldonazzo Lake.

SFI Category 1 and 2

These categories are located in coincidence with areas where the Because their extension occupied only the 29% of the whole lake shorezone width is wider thanks to the presence of reed belts or perimeter, it is advisable to safeguard these areas (most are in thanks to the continuity with the surrounding environment given fact already protected thanks to the special instituted biotopes). by the road tunnels. The vegetation is here mainly hygrophilous An improvement could be given with the growth of a reed belt, and a good shore functionality is assured (figures 22 and 23). but further study are necessary to verify this possibility.

Figures 23, 24> examples of SFI categories 1 and 2.

23 SFI Category 3

The stretch occupies most of the western side of the lake, running along the pedestrian-bike path (figure 24). Even though the riparian vegetation is almost continuous and there is a good diversity, the width of the lake shorezone is penalized by the presence of the path running along it. The provincial road running parallel to it could also represent a source of pollution for the lake, and it is therefore important not to worsen the condition of this stretch.

Figure 24> Example of SFI category 3.

SFI Category 4 and 5

The low SFI values are given by the high artificiality of the or English gardens, covered by few trees probably planted shore and the lack of riparian vegetation: superficial waters and for shading (figure 25); the second typology, located in the possible no-point source pollutant can flow directly into the lake southern-eastern side of the lake, is characterized the presence in this area without encountering any particular barrier. of impermeable sustaining walls that support garden for private The stretches in this category fall into two main typologies: the summer houses, and that causes an interruption between the first is constituted by artificial beaches made of small pebbles lacustrine and terrestrial environment (figure 26).

Figures 25, 26> Examples of SFI categories 4 and 5.

24 Caldonazzo Management Recommendations

Caldonazzo Lake improved its quality thanks to the restoration It is therefore recommended to: works accomplished in the past years, such as the waste water • Preserve the already existing natural areas, including the collector. protected biotopes Although, the absence of a vegetation buffer zone, especially • Consider an environmental friendly development, limiting the along the southern shores where the pressure from agriculture use of cement is higher, represents a weakness. • Keep the current limitation on the use of boat engines Another threat for the shorezone functionality is represented by • Supervise the tourist offer growth/development the requests to continuously expand the beaches, parking and • Publicize the tourist offer considering the natural aspects of tourist structures, all actions that will increase the artificiality the lake of the shorezone, therefore loosing existing areas with good • Organize a sensitization campaigns for local stakeholders and functionality. managers on the role of the lake and its need to be healthy In the past fifthy years, the use of Caldonazzo lake leaned • Promote lake environmental education in schools, maybe more and more toward a tourism related use. This resulted in using the concept of the “house on the lake”, as proposed in a gradual decrease of natural areas to create new beaches, the SILMAS project tourist infrastructures, summer houses, roads and parking. The SFI index showed how these human actions affected the lake shorezone functionality. Nowadays, the lake offers many tourist attractions and it would be recommended to improve the quality of the tourist offer, rather than the quantity, assuring an ecological vision with protection of the already existing natural sites.

Authors

For more information

Full report available at http://www.appa.provincia.tn.it/appa/pubblicazioni/-Acqua/

25 Idro Lake

Location and Origin

Lake Idro is a south alpine deep lake located in the Northern consequence of the huge drawdown and water level fluctuations part of Italy at an altitude of 368 m a.s.l. across the provinces of imposed by hydropower exploitation, and the increase in Brescia and Trento (between Lombardy and Trentino-Alto Adige pollutants delivery from the its catchment, since early 1970s, Regions). The lake surface is equal to 11.03 km2, with a maximum the basin has been shown a progressive worsening of water length of 9.4 km, a maximum depth of about 124 m and a quality and biotic component. A major ecological effect of these volume of about 8.5* 108 m3. According to its trophic status the external perturbations is the increase of the bottom layer of lake has been considered to be meso-eutrophic; limnologically, water (usually free of oxygen) moved from about a depth of 70- the lake belongs to the meromictic type of circulation. Currently, 80 m (late 1960s) up to currently 40-50 m. In the last ten years, the upper mixed water zone (the oxic layer) varies between 40 a progressive steep reduction in the amplitude of artificial water m and 50 m of depth and approximately more than 50-60% of level fluctuations, coupled with the accumulation of organic the entire lake volume is permanently stratified and oxygen-free. matter and nutrients in waters and surface sediments, have enhanced a rapid and intense proliferation of littoral vegetation The basin plays an important part in the economy of the local and recurrent cyanobacterial blooms. population essentially in terms of tourism and recreation; The present investigation has been carried out from a boat however, it is also the first Italian natural lake completely (performing a complete circumnavigation of the lake during the converted into a hydroelectric reservoir in the mid-1930s. As a surveys) and integrating them with aerial photographs.

Results

On the whole, Lake Idro has 26.670 m of shoreline divided into pointed out; on the other hand, 15 stretches show a moderate 44 distinct stretches, few of which are submitted to intense level of shorezone functionality with a total length of about 9.150 anthropogenic perturbations that resulted in a localized alteration m, in presence of slight levels of human pressure that resulted of the lake shores and/or beaches (figure 27). Consequently, into a moderate alteration of littoral and hydro-hygrophilous a poor SFI value is exclusively associated to the 16% of the vegetations (e.g., periodical cutting of riparian belts, installation total length of the shoreline (about 4.340 m) that comprised the of quays or boas). The remnant stretches (21 lake sectors with a littoral sector of the lakeside towns and built-up areas, splitting length of 13.180 m equal to the 50% of total shoreline extension) into 8 distinct stretches with very low values of functionality. No display a good or excellent conservation stages in presence of shoreline sectors with a fair evaluation (4, SFI value) have been natural and near-natural conditions (figure 28).

BASSE BASSE DEF DEF

Figure 27> Results for Lake Idro. Figure 28> Percentage distribution of the functionality level of Idro Lake.

Stretches SFI Value Total m Percentages identified Excellent 4 2400 9% Good 17 10780 40% Moderate 15 9150 34% Poor 0 0 0% Bad 8 4340 16% TOTAL 44 26670 100% Table 5> Summery of the SFI results.

26 SFI Category 1 and 2

These categories represent in total the half of the lake perimeter with a clear predominance of the “good” conditions (equal to the 41%). To the excellent class are related 4 lake sectors that included stretches in natural conditions, not easily reachable by humans if not by boats (figure 29). These sectors are BASSE characterized by well-developed fringes of hydro-hygrophilous vegetation, although in general the water-terrestrial ecotones are mostly reduced to a thin belt of about 5-10 m. The second DEF category is differentiated by the irregular presence of paths and not-paved sidewalks used as approaches to the lake shore, sparse residential settlements or not-intensive agricultural Figure 29> SFI Category 1 and 2. areas. Generally, these stretches display a near-natural condition with good conservation status characterized by, in the main, continuous riparian and littoral vegetation stands and only sporadic presence of artificial substrates.

SFI Category 3

The third category includes the stretches that are characterized by non-negligible levels of anthropogenic pressures; however BASSE in presence of several natural attributes as well as wet fringe vegetations or littoral ecotones, although, the expected helophytic communities are frequently replaced by invasive or less exigent species. Nevertheless, these sectors are included DEF into not-intensive agricultural lands and neighbourhoods (figure 30). Figure 30> SFI Category 3.

SFI Category 5

Category 5 includes the artificial shorelines (in presence of retaining walls, piers, docks, etc.) that are classified in the worst functional status. This typology is prevalently found in the urban BASSE contexts, especially in the southern and northern sectors of the basin. Natural vegetation is scarcely represented and frequently these sectors are characterized by beaches that are periodically repaired using allochthonous materials (figura 31). DEF

Figure 31> SFI Category 5.

Management Recommendations

Lake Idro shows rather high Shorezone Functionality Index fact, agricultural activities in the watershed and wastewater from (SFI) values; at least 84% of its shoreline is in a good status resident population and from trout farms are probably the most of conservation. Our results suggest that high levels of relevant. Nevertheless, the presence of well preserved fringe anthropogenic alteration are only detected in correspondence vegetations (e.g., hydro-hygrophilous plant belts) guarantees an with urban residential and settlements areas. Generally, the good efficient filtering functionality and stimulates a rather slow but status of littoral and riparian contexts is in contrast to the current constant control of the exogenous input and the internal nutrient worst status of water quality. Among the human pressures, in load.

Authors For more information

Dr. Rossano Bolpagni Dr. Rossano Bolpagni Dipartimento di Scienze Ambientali, Università degli Studi Dipartimento di Scienze Ambientali, Università degli Studi di Parma - Department of Environmental Sciences, di Parma - Department of Environmental Sciences, University of Parma University of Parma V.le G.P. Usberti 11 / A - 43125 Parma V.le G.P. Usberti 11 / A - 43125 Parma Tel: (+39) 0521 905696 Tel: (+39) 0521 905696 27 [email protected] [email protected] Wörthersee

Location and Origin

As one of the most popular bathing lakes the Lake Wörthersee is meromictic lake moved from about a depth of 70 m up to situated in Carinthia, close to its capital, Klagenfurt, located near 45 m. The pollution with phosphor-polluted waste water grew up the eastern shores of the lake. rapidly and algae blooms appeared, severely handicapping the With an area of 19,39 km² and a length of 16,5 km Lake bathing activities and tourism. In 1963 the responsible authorities Wörthersee is even the largest lake of Carinthia. It is situated reacted, setting measures and implementing a law for keeping in a valley aside off the main draining line of the river Drau and clean the lakes. As the first guiding project the purification plant embedded in the hilly Mittelkärntner Hügelland. The valley ridge Klagenfurt (1967) was built. These measurements of stabilization is a tectonic disorder, which was covered by an ice age glacier. in the catchment area (like the built of the drainage system The lake basin stretches from the east to the west, is structured around the lake) made the lake again a major attraction magnet by islands, peninsulas and underwater rises and parted into for summer tourism. three. The lake`s name has its origin in the Old High German The maximal depth amounts to 85,2 m, while there is a average “Werdersee”, meaning lake with 4 islands. One of them, Maria inflow of 2.460 l/s. A great number of smaller brooks flow in Wörth, was connected to the mainland by decreasing the water from all sides of the lake. The biggest is the Reifnitzbach with an level in 1770. average substance of 630 l/s. The water residence time of 10,5 years has been calculated. The investigation for the SFI has been carried out by using As a consequence of the strong burdens with nutrients videos, taken from boat and helicopter, and integrating them (eutrophication), which were caused by the quick development with aerial photographs and on-site surveys. of tourism during the 1960s, the oxygen-free zone of this

Results

The overall shoreline of Lake Wörthersee amounts to 46.300 encountered during the survey. 10 from the remaining 16 m. Most of it is interested by a huge anthropogenic pressure, stretches resulted to have a moderate shorezone functionality. resulting in diffused settlements along the lake waters (figure Its length amounts to 6.755 m, where human interventions, 32). Popular bathing localities like Velden, Pörtschach and Maria especially in front of private properties, result in decreased Wörth attract many tourists during the summer months. As a hygrophilus vegetation and the installations of piers for bathing result, nearly 50 % of the shoreline shows a poor SFI value. purposes. The remaining sections stand in the range of Human disturbance results in artificial shores and impermeable excellent/good values, natural and near-natural conditions could sustaining walls. 15 stretches without functionality has been be achieved (figure 33).

BASSE BASSE DEF DEF

Figure 32> SFI results for Lake Wörthersee. Figure 33> Percentage distribution of the functionality level of WörtherseeLake.

Stretches SFI Value Total m Percentages identified Excellent 8 5269 11% Good 6 2294 5% Moderate 13 17136 37% Poor 0 0 0% Bad 15 21601 47% TOTAL 42 46300 100% Table 6> Summery of the SFI results.

28 SFI Category 1 and 2

These categories occupy together just 17 % of the lake good state, as some of those stretches are rather narrow and perimeter. The excellent condition is characterized by areas characterized by the close presence of paved streets. Such under nature protection (protection area “Walterskirchen” and streets run all around the lake and often approach the lake area around the lake outlet, the Glanfurt) or by stretches in near- shore. The surrounding territory of these stretches in excellent/ natural conditions. The first are distinguished by the presence good conditions is distinguished by hilly, mostly woody territory. of hygrophilous species and extensive weed-patches. Stretches Sometimes there are sparse residential settlements, while in near-natural conditions sometimes also resulted to be in a intensive agricultural areas are lacking (figure 34 and 35).

BASSE DEF

Figures 34, 35> SFI Category 1 and 2.

SFI Category 3

This category is distinguished by stretches that result under clear anthropogenic pressure, but still presenting some natural attributes: permeable shore reinforcements or wet reed patches for example. Otherwise the majority of the shorezones is in BASSE private hand and often lack in hygrophilous vegetation, replaced by short grass. Here often the filtering functionality of the shorezone vegetations goes missing. The stretches are mostly located between the major touristic DEF settlements, on the northern shore as well on the southern coast (figure 36). Figure 36> SFI Category 3.

SFI Category 5

Impermeable, artificial shorelines distinguish the stretches classified in the worst category. These sections can be prevalently found in the areas interested by high population density, especially in the western basin. Reed belts are rare, BASSE wooden docks regularly present (figure 37). DEF

Figure 37> SFI Category 5.

29 Management Recommandation

Lake Wörthersee shows a strong anthropogenic pressure, A problem may derive from the increasing number of docks especially those deriving from seasonal tourism. The lake is and piers along the Wörthersee shores. They may endanger the surrounded by extensive wooden areas, while agricultural natural habitat structures of the local fauna, especially the fish surfaces almost are missing (the whole catchment area is fauna. characterized by less than 20 % of agricultural surfaces). As The SFI shows that the lake shore along Lake Wörthersee the nutrient input is supposed to be low, the lacking filtering has reached obstructions of a scale that affects seriously the functionality of almost half of the shoreline does not endanger natural functions of the bank, such as filter and buffer effects. It the water quality of the lake. Domestic waste waters as well is therefore generally recommended to neglect interventions in as waste waters deriving from other urban infrastructures are intact riparian sections (rated as very good or good). Similarly, collected in the local drainage system and discharge outside the in sections with strongly modified banks, constructions (piers, lake’s watershed basin. marinas) should be allowed only in exceptional cases.

Authors

Dr. Michael Schönuber Kärntner Institut für Seenforschung Kirchengasse 43 / 2. Stock 9020 Klagenfurt am Wörthersee Sekretariat: (+43)(0) 5 0536 578 21 [email protected]

For more information

Dr. Roswitha Fresner Kärntner Institut für Seenforschung Kirchengasse 43 / 2. Stock 9020 Klagenfurt am Wörthersee Sekretariat: (+43)(0) 5 0536 578 21 [email protected]

Full report available at

http://www.kis.ktn.gv.at/159890_DE-KIS-Publikationen

30 Millstätter See

Location and Origin

The second largest lake of Carinthia, the Millstätter See, has an The name of the lake derives from the village of Millstatt. area of 13, 28 km². As it has a depth of 141 m and a volume of Frequently you can hear that the name of Millstatt derives 1.204,6 million m³, it’s also the deepest and water-richest lake. from the Latin “mille statuae” and is based on the legend of St. The main inflow of the Millstätter See is the Riegerbach with its Domitian. He should have thrown 1.000 heathen statues into the catchment area of 188, 8 km² and an average discharge of 3.100 lake, when he converted to Christianity. More probably, however, l/s. Besides by this the lake is also fed by a number of smaller is that the name results out of the pre Slavic “Melissa”, meaning brooks. The emissary, the Seebach, has 5.350 l/s on its average. mountain brook or hill brook. With the increasing tourism since the 1950s a change of water The investigation for the SFI has been carried out by using quality started, which expressed in the algae bloom and the videos, taken from boat and helicopter, and integrating them loss of the high visibility. The burdening of the lake with home- with aerial photographs and on-site surveys. made waste water was responsible for this phenomenon. At that time the waste waters were directly led into the lake and its tributaries. With the beginning of the canalization (1968 to 1994) the re-oligotrophication process has started and with it the eye-catching algae–blooms has disappeared. The water is of excellent quality today.

Results

With a length of almost 27 km the shoreline of Lake Millstätter is could be distinguished by typical human pressures, resulting consistently shorter than those of Lake Wörthersee, the largest in residential and recreational facilities. Those anthropogenic Carinthian lake. As a popular bathing lake, there are several interventions caused an artificialization of the shoreline, often touristic settlements along its shores, especially along the using impermeable materials, and strongly impacting on the northern bank line (figure 38). Most of the stretches that showed natural, hygrophilus vegetation. The poorest functionality could low shorezone functionality are placed there, while the steep be encountered on a total of 9.7 km. Reed belts along the shore southern shores distinguish themselves through a near-natural are rather rare because of the high slope of the shorezones. state and low human pressures. 25 different stretches have been identified. 6 of them showed a excellent-good state, for a overall length of over 10.000 m (or 39 %). The remaining stretches

BASSE BASSE DEF DEF

Figure 38> SFI results for Lake Millstätter See. Figure 39> Percentage distribution of the functionality level of Millstätter Lake.

Stretches SFI Value Total m Percentages identified Excellent 5 10.111 38% Good 1 285 1% Moderate 10 6755 25% Poor 0 0 0% Bad 9 9705 36% TOTAL 25 26856 100% Table 7> Summery of the SFI results.

31 SFI Category 1 and 2

One third of the lake perimeter, characterized by steep, hilly The only stretch with good functionality is in presence of a cliff, surroundings especially towards south, is occupied by stretches where the vegetation is rarefied due to natural reasons. falling in these two categories (figure 40 and 41). On the southern Wet reeds formations are rare and narrow as the lake ground is shores is dominating the excellent status, as human pressures rather steeply sloping. result very low due to the morphology of the surrounding territory. Southwards, on the slopes of the ridge that divides the lake from the Drava valley, woodland is clearly predominant.

BASSE DEF

Figures 40, 41> SFI Category 1 and 2.

SFI Category 3 and 5

These categories are dominating among the numerous Private gardens and public beaches are also often completely settlements and the traffic infrastructures along the northern lacking of hygrophilus vegetation. Road protection measures, shore (figure 42 and 43). Erosion protections are mostly made prevalently of riprap, narrow the shorezone significantly impermeable in presence of residential and public facilities. along the northern bank line. Wet reeds patches are rare.

BASSE DEF

Figures 42, 43> SFI Category 3 and 5.

Management recommendation

Observing the surroundings of the lake huge differences can The SFI shows that the lake shore on the north side of Millstätter be observed. To the south shores and hinterland are in a near- See has reached obstructions of a scale that affects seriously natural state, with very low human pressures. A nutritional input the natural functions of the bank, such as filter and buffer effects. to the lake from this region can be excluded. On the other It is therefore generally recommended to neglect interventions in hand, the remaining shores show huge anthropogenic impact intact riparian sections (rated as very good or good). Similarly, on the shorezones. Residential and touristic settlements, road in sections with strongly modified banks, constructions (piers, infrastructures and recreational spaces heavily influence its marinas) should be allowed only in exceptional cases. filtering functions. Nutritional input should be expected only from nearby agricultural surfaces, but actually they seem not to influence the water quality of the lake.

32 Authors

Dr. Michael Schönuber Kärntner Institut für Seenforschung Kirchengasse 43 / 2. Stock 9020 Klagenfurt am Wörthersee Sekretariat: (+43)(0) 5 0536 578 21 [email protected]

For more information

Dr. Roswitha Fresner Kärntner Institut für Seenforschung Kirchengasse 43 / 2. Stock 9020 Klagenfurt am Wörthersee Sekretariat: (+43)(0) 5 0536 578 21 [email protected]

Full report available at http://www.kis.ktn.gv.at/159890_DE-KIS-Publikationen

33 Lake Bohinj

Location and Origin

Lake Bohinj in the largest natural lake in Slovenia. It was shaped Ecological state of lake Bohinj was described as “excellent” by glacial and tectonic forces approximately 10.000 years ago. between 2006-2009 state monitoring, in 2010 however the The Lake lies at 526 metres a. s. l., covers 3.28 km2 and contains ecological state was degraded to “good”. The reason for 92.5 million m3 of water. Maximal depth is 45 m and the retention degradation of the ecological state estimate was lower diversity time of water is 4 months. of benthic invertebrates which respond to hydro-morphological The main tributary of lake Bohinj is river Savica with average changes in littoral zone. These changes in littoral zone are caused discharge between 4.6 – 5.6 m3s-1. Other tributaries are smaller by different natural and anthropogenic influences constantly rapid streams and underground sources. The outflow of the present in lake Bohinj (ARSO, 2010). In 2011 the ecological state Lake is river Jezernica with average discharge between 6.6 – 9.9 was again assessed as “excellent”. m3s-1 which merges with river Mostnica from the valley Voje. After the confluence the river si called Sava Bohinjka. The area of the Lake is within Triglav National Park, a designated nature protection area where nature conservation is a priority. Catchment area of the Lake covers approximately 100 km2 of mountainous and scarcely inhabited land.

Results

Lake Bohinj shorezone is approximately 11.35 km long. SFI Stretches SFI Value Total m Percentages index of the Bohinj shorezone was estimated partly from the identified land and partly from the lake (figure 44). Excellent 4 6704 59% We divided the shorezone into 11 sections for which SFI values Good 1 500 4% were estimated. SFI values for lake Bohinj range from “excellent” to “moderate” without any sections in “poor” or “bad” condition. Moderate 6 4146 37% Four sections have “excellent”, one section had “good” and six Poor 0 0 0% have “moderate” SFI values which reflect the human use of the Bad 0 0 0% shorezone of the lake. TOTAL 11 11350 100% Table 8> Total length and percentage of length of sections with different SFI values of lake Bohinj.

BASSE DEF

Figure 44> Map of lake Bohinj SFI values for shorezone. Figure 45> Relative length of sections with different SFI values of lake Bohinj.

Excellent value of SFI for shorezone was estimated for the north shore where anthropogenic influence is very low. Entire north shore is natural and covered with forest which spreads upwards to the slopes of Pršivec and is only accessible by a footpath (figure 46). BASSE DEF

34 Figure 46> The north shore is natural and covered with forest. Moderate values of SFI were estimated for the north-east part where anthropogenic influence was considerable in the past. Forest was cut to create pastures which were later abandoned. Despite the succession meadows are still open which affects the purifying function of the shorezone. There are no other human activities present which would increase the drainage of nutrients BASSE into the lake (figure 47). DEF

Figure 47> Abandoned pastures in the north-estern part of lake Bohinj.

Moderate SFI values were also calculated for the eastern shorezone which is under the influence of swimming area, village (Ribčev Laz) (figure 48 and 49), several buildings, small peer, farmland and local roads. Touristic activities are concentrated within this area and part of the shorezone is stabilized with concrete blocks. This area is flat and only a small part is covered BASSE with forest. Purifying function of this section is reduced. DEF

Figure 48, 49> Eastern shore is affected by anthropogenic influence where touristic activities are concentrated. Stretches SFI Value Total m Percentages identified

Excellent 4 6704 59% The entire south shore is lined by a local asphalt road with Good 1 500 4% relatively dense traffic in the summer months. The shore Moderate 6 4146 37% gently slopes upwards and is mostly covered with forest Poor 0 0 0% which is interrupted by few buildings. Entire south shorezone has excellent or good SFI values. The purifying function of the Bad 0 0 0% shorezone is good, however the shorezone is relatively narrow BASSE TOTAL 11 11350 100% due to the road. Western shore (Ukanc) has moderate SFI values due to the touristic infrastructure (camp site) and swimming area (figure DEF 50). Located in the immediate vicinity of the shorezone are also bungalows, hotel and farmland. Purifying function within this

area is reduced. Figure 50> Swimming area in the western part of lake Bohinj.

Part of the western section is covered with occasionally flooded forest near the Savica inflow (figure 51). This section has excellent SFI value due to high uptake of nutrients from the water by the forest vegetation. BASSE DEF

Figure 51> Flooded forest with reedbeds next to the Savica inflow.

35 Management reccomandation

In general the ecological state of lake Bohinj is excellent with into the lake is small. Additional pressure is due to swimming in more than half of the shorezone with excellent SFI index non-designated areas of the shore. If tourism and degradation values which is rare among Alpine lakes. However, we noticed of the shore do not increase the state of lake Bohinj shorezone differences between parts of the shore under anthropogenic should remain excellent. Managing authorities should pay influence and near-natural parts. Most of the buildings are special attention to activities on the western and eastern shore connected to the sewage system and farmland is mostly used where the purifying functions are already reduced. as extensive pastures and meadows therefore nutrient seeping

Authors

Tina Leskošek Dr. Irena Bertoncelj Uroš Žibrat National Institute of Biology National institut of biology Nazorjeva 22 Večna pot 111 Večna pot 111 2000 Maribor 1000 Ljubljana 1000 Ljubljana Slovenia Slovenia Slovenia [email protected] +386 (0)59 232 700 +386 (0)59 232 700 [email protected] [email protected]

For more information

Tina Leskošek Nacionalni inštitut za biologijo Večna pot 111 1000 Ljubljana +386 (0)59 232 700 [email protected]

Literature

Kakovost jezer v Sloveniji v letu 2010 (ARSO, 2010, http://www.arso.gov.si/vode/jezera/JEZERA_kratko_2010_MDT.pdf)

Ocena stanja jezer v Sloveniji v letu 2011 (ARSO, 2011, http://www.arso.gov.si/vode/jezera/Poro%C4%8Dilo%20JEZERA%20_2011.pdf)

36 37 Conception et réalisation oct. 2012