1 Proposed construction of dams on Morača river: environmental risk assessment of Morača canyon and Skadar lake Darko Saveljic (bird expert) Danilo Mrdak (fish expert) Mirko Kneževic (biotechnology expert) Jelena Marojevic (experts coordination) Francesca Antonelli (overall coordination) Short version of three reports commissioned by WWF MedPO and Green Home under the framework of Sharing Waters Project - Skadar Lake component. DRAFT Rome, June 2009
Mirko Kneževic (biotechnology expert) Jelena Marojevic (experts coordination)
Francesca Antonelli (overall coordination) Short version of three reports commissioned by WWF MedPO and Green Home under
the framework of Sharing Waters Project - Skadar Lake component.
Rome, June 2009
Table of contents 1. Introduction ........................................................................................................................... 3 2. Executive summary............................................................................................................... 3 3. Hydrology of Skadar lake and Morača river and predicted impact of dams on Skadar water regime ................................................................................................................................. 4
3.1. Hydrology....................................................................................................................... 4 3.2. Flooded areas of Skadar lake and correlation with Morača river.............................. 6 3.3. Simulated impact of dams on Skadar water regime .................................................. 7
4. Bird fauna of Morača river and Skadar lake ....................................................................... 9 4.1. Bird fauna of Morača canyon and Skadar lake ......................................................... 10 4.2. Predicted consequences of dams on the bird fauna and flora................................ 11
5. Fish fauna of Morača river and Skadar lake ..................................................................... 12 5.1. Fish fauna of Skadar lake and Morača river ............................................................. 12 5.2. Commercial fish stock and its economy .................................................................... 14 5.3. Predicted consequences of dams on fish .................................................................. 14
6. Conclusions.......................................................................................................................... 16 7. Literature ............................................................................................................................. 17 List of figures Figure 1. Correlation between Skadar lake water level (hydrological station of Podgorica)
and Morača flow (Kneževic, in prep) . ................................................................................ 5 Figure 2. Water inflow of Skadar lake (modified from Radulović 1997).................................. 6 Figure 3. Water outflow of Skadar lake (modified from Radulović 1997). .............................. 6 Figure 4. Wet surface categories of Skadar lake (Knežecic, in prep.). ................................... 7 Figure 5. Ornithological reserves on Skadar lake (G. Earth/ V. Bušković)........................... 11 Figure 6. Composition of Skadar lake fish fauna (Mrdack, in prep). ..................................... 13 Figure 7. List of most important endemic fish species of Skadar lake and IUCN
conservation status. List of categories available at http://www.iucnredlist.org/info/categories_criteria1994 - categories...................................... 13
List of tables Table 1. List of fishery species of Skadar lake (Mrdak D. et al. 2003) .................................. 14 List of annexes ANNEX 1. Ornythofauna of Morača canyon, their status according to international
conventions and EU Bird Directive ANNEX 2. Variation of water level depending on realized or retained water quantity
(Morača flow data used to derive the table provided by HMZ Podgorica) ANNEX 3. Variation of Skadar lake surface depending on water quantity that would be
realized or retained in the accumulations (Moraca flow data used to derive the table provided by HMZ Podgorica)
Skadar lake and Morača river present both outstanding flora and fauna values at national and international level and the proposed construction of four dams on Morača has raised attention of the civil society as well as of the investors in terms of environmental and socio-economic impacts. In 2009 three studies were commissioned by WWF Mediterranean Programme and Green Home, respectively one on birds and one on fish of Morača river and Skadar lake, and one on the hydrology of Morača river and Skadar lake and the predicted flow/water regime changes in the river and lake due to the construction of four dams. The fauna study describes the current conservation status of species and habitats and the predicted impacts of Morača dams on that conservation status.
The methodology of the studies is a mixture of desktop literature review and
data analysis (fish and hydrological studies) and field data collection (birds study). Some important discoveries were made on the relation between Morača flow and Skadar lake as well as the importance of the biodiversity of Morača river.
The three studies are finalized and the reports about to be made public. This
document is a summary of the main findings of the three studies. They were conceived to raise the attention of decision makers and investors on the consequences of building dams on Morača and open a dialogue on this concern in the belief that the NGO sector can give an important contribution to sound decision making.
The Strategic Environmental Assessment (SEA) of four dams to be
constructed on Morača river in on going and these studies should be taken into serious considerations for the final results of the SEA. 2. Executive summary
WWF and Green Home have commissioned three studies to simulate the impact on Morača river and Skadar lake of four dams to be built on Morača river.
One study had the objective of clarifying the hydrological connections between
Morača river and Skadar lake and simulate the impact of the construction of four dams on the water regime of Skadar lake. It was based on hydrological data collected in the past 40 years (1961-2001) by the responsible authorities which were used for mathematical simulations. The study had proved that the four dams on Morača will have an impact on the delicate water regime of Skadar lake and will change considerably the wetlands around the lake.
A second study identified Morača river as a very important hotspots for birds
and plants at a national and regional level and predicted that the impact of the four dams on these values will be very high wiping out key rare habitats which are home to a unique amount of plant species and birds.
The third study assessed the fish fauna of the river and the lake and predicted
an impact on rare endemic trout species in Morača river and on a very economically important species of Skadar lake, the carp. An economic loss of approximately 1.416.666 € per year is estimated.
3. Hydrology of Skadar lake and Morača river and predicted impact of dams on Skadar water regime
The hydrological study had the objective of clarifying the hydrological
connections between Morača river and Skadar lake and simulate the impact of the construction of four dams on the water regime of Skadar lake. It was based on hydrological data collected in the past (1961-2001) by the responsible authorities used for mathematical simulations.
The Skadar lake basin belongs to the Adriatic watershed and its surface is 5,490 km2. It is rich in water sources of various quantities with the two biggest rivers, Morača and Zeta and their numerous tributaries, which directly supply the lake.
Oscillation in the water level of Skadar lake depends indeed on the lake’s charging and discharging regime. Observing the water measurements during the period 1961-2001, the lowest water level was registered in September 1985 amounting to 4.76 m, while the average water level for the same period was 6.46 m a.s.l. The highest water level was registered in January 1963 amounting to 9.86 m a.s.l. The water level of Skadar lake determines its cumulative area, depth and water quantity. Excluding the existing wells in the lake the maximum water level is over 15m, while the minimum is around 10m. In this study the surface area of the lake and the water quantity were calculated on the basis of measured (from literature) water levels and topographic maps (Radulović 1997).
The most important components affecting the water balance of Skadar lake are the rivers Morača and Zeta. The high oscillation of Skadar lake water level and the oscillation of water flow of Morača and Zeta rivers are determined by high precipitation in winter and a lack of precipitation in summer. The dependence of Skadar Lake water level on Morača river flow is confirmed by a regression analysis carried out by Kneževic (in prep.) for this study.
Figure 1. Correlation between Skadar lake water level (hydrological station of Podgorica) and Morača flow (Kneževic, in prep) .
The surrounding plains have a number of water sources (wells) known as “oka”
which are found in Bjelopavlicka plain and in Zetska plain (also called “vrulje”). A great number of them are situated on the bottom of Skadar lake. Groundwater also springs in Skadar lake. The water quantity supplied into the lake by the vrulje is impossible to measure exactly and even a rough estimate is difficult. Radulović (1997) though has estimated the annual average for the whole watershed at around 60 l/s.
As mentioned Radulovic (1997) reported that the main inflow of the lake is the
river Morača, which supplies the lake with more than 60% of its water. The remaining is divided into: 9% from precipitation, 18% from wells, and 17% from other water flows (Figure 2). The main outflow of the lake is Bojana river (Figure 3). It is important to mention that the water level in the lake depends also on the discharge of river Drim in Albania. Nevertheless since 1973, when the Fierza accumulation was constructed in Albania, its flow is managed (hence stable) and the lake water level has become more dependent on Morača river flow.
Other w ater f low s5%
Other w ater f low s
Figure 2. Water inflow of Skadar lake (modified from Radulović 1997).
Figure 3. Water outflow of Skadar lake (modified from Radulović 1997).
Water and sediment analyses of the lake show the difference between physical
and chemical conditions in the pelagic and littoral waters, especially where aquatic macrophytes are growing. These differences are the result of the influence of pollutants, chemical processes, sediment and biological production of the lake.
3.2. Flooded areas of Skadar lake and correlation with Morača river
Waterlogged areas around Skadar lake can be subdivided into several zones (Figure 4):
• Zone I with swampy soils and peats spread below 5.5 m.a.s.l. including northern areas surrounding Malo Blato. These areas are under water, or water is right beneath the soil surface, for almost the whole year. When the soil is not flooded, groundwater is at a depth of less than 1m, and is due to Skadar Lake water level (minimum water level 4.6 m). This zone is
overgrown with boggy and swampy vegetation and a very important ecosystem. The total surface of this area is 6,006ha, of which Skadar lake covers 5,800ha and Malo Blato 206ha.
• Zone II encompasses between 5.5 and 8 m.a.s.l., and it occupies the south surroundings of Malo Blato. These soils are exposed to constant flooding during the year, because during a long period of the year the water level of Skadar lake fluctuates between these two levels. Going further from the coast the habitat changes from swampy to natural meadow, rarely turning into arable land. The total surface of this zone is 4,262ha, of which Skadar Lake covers 4,005ha and Malo Blato occupies 257ha.
• Zone III extends in the areas above 8 m.a.s.l. Flooding in this zone is periodical, and most often from November to February. The level of groundwater fluctuates from several tenths of centimeters in autumn and spring to 4-5m during the summer. The total surface of this zone is 1,475ha.
• Zone IV is the area directly affected by high floods of Morača river. It is periodically flooded and the total surface if 567ha. In this zone the water table is shallow often at a depth lower than 1m.
Figure 4. Wet surface categories of Skadar lake (Knežecic, in prep.).
3.3. Simulated impact of dams on Skadar water regime According to the available project documentation two variants of a cascade of
hydropower plants is foreseen. In the first one a system of four hydropower plants on Morača river is foreseen, and in the second variant water diversion from Tara to Morača is predicted requiring an extension of the first one. In the first variant each dam will be furnished with two sets of turbines, a third one (for each dam) will be foreseen (but not built) in case the water from Tara is made available. Each set of turbines is supposed to be fed by the same flow of 2x60 m3/s, designed in a way that space is left for a third set and an installed flow of 3x60 m3/s (in case of the extension of a project).
Accurate prediction of the impact of the construction of the dams on Skadar Lake water level is difficult due to the complexity of the Skadar Lake watershed. In
this study simulations were conducted by using the specific polynomial relationship between the river Morača flow and Skadar lake water level obtained by analyzing historical data. The investigation of the boundary conditions and other characteristic levels of water accumulation was done by using a historical set of data (1961-2001) for the maximum, minimum and average water level of Skadar lake. Six different management options were examined: the release or charging of the total volume from the accumulation, release or charging of the useful water volume from the accumulation, and the release or charging of half of the useful water volume from accumulation.
The following are the results of the six simulations: 1) In the case of charging the total gross volume in the accumulation,
assuming that the lake water is at a minimum level it will decrease from 81cm to 82cm in April, May and January, to 92cm in October. In the case of an average water level it will increase from 75cm in December to 86cm in September and October. In the case of a maximum water level it will increase from 69cm in January, 77cm in April and May, to 82cm in August.
2) In the case of releasing the total gross volume from the accumulation, assuming that the lake water is at a minimum level it will increase from 88cm in January and April, 89cm in May, 107cm in July, 108cm in November, 114cm and 115cm in August and September, respectively, and 119cm in October. In the case of an average water level it will increase from 80cm in January, 81cm in April and May, up to 98cm in August and September. In the case of a maximum water level it will increase 72cm in January, 73cm in April, 75cm in May, up to 89cm in August.
3) In the case of charging half of the useful water volume, the decrease of the maximum, minimum and average water levels of the lake will be between 27cm and 42cm for all the months, with higher values from June to November than in other periods.
4) In the case of discharging half of the useful water volume, the increase of the maximum, minimum and average water levels of the lake will be between 27cm and 42cm for all the months, with higher values from June to November than in other periods.
5) In the case of releasing the useful water volume from the accumulation, assuming that the lake water is at a minimum level it will increase from 69cm in January, April and May, to 91cm in October. In the case of average water level it will increase from 63cm in January, up to 76cm in August and September. In the case of maximal water level it will increase from 57cm in January to 69cm in August.
6) In the case of charging the useful water volume in the accumulation, assuming that the lake water is at a minimum level, the latter will decrease from 65cm in January, April and May, to 74cm in October and November. In the case of average water level it will be reduced from 60cm in January, February and December up to 69cm in August and September. In the case of maximal water level it will decrease from 55cm in January to 65cm in August.
Depending on the water quantity released or withheld in the accumulation lake
a value of increase or decrease of Skadar Lake water level was obtained. The resulting water level oscillations due to the different management options on the accumulation of Morača river and the related changes of Skadar lake surface (depending on the water released or withheld in the accumulation) are presented in Errore. L'origine riferimento non è stata trovata. and Errore. L'origine riferimento non è stata trovata..
According to the simulations obtained, the surface could vary from a
minimum level of 281km2 in August to 494.7km2 in January. Some areas would dry up starting from the shallower ones.
These thresholds have never been registered in the past 40 years. In short the natural water regime of Skadar lake would be disrupted and as a consequence the habitat of the currently temporarily flooded areas in the northern rim of the lake relying on this water regime would be disrupted as well.
It is important to remark that to quantify accurately the relation between the
accumulation lakes on Morača river and the variation in the water level of Skadar lake and the related changes in its surface, detailed information on water management of the hydropower plants is necessary. This information includes the water quantity in the accumulation withheld and released up to the complete gross volume (equal to 0.34km3), the water quantity in the accumulation withheld and released up to its useful volume (equal to 0.27km3) and water quantity in the accumulation withheld and released up to half of the useful volume (equal to 0.13km3).
In our study we have proved though that a careful evaluation of the impact of various management options must be taken into account when planning the operations of the dams. 4. Bird fauna of Morača river and Skadar lake
An analysis of the predicted impact of dams construction on Morača canyon has assessed that the condition of flora and fauna of the canyon upstream the dams would be highly damaged as well as the biodiversity downstream.
4.1. Bird fauna of Morača canyon and Skadar lake
130 bird species have been registered in Morača canyon, of which 127 species have a protected species status (42% of the total number of protected bird species in Montenegro), 84 are confirmed to breed in the canyon while for 10 species the breeding has not been confirmed. This accounts for 46% of the total number of breeders in Montenegro (Puzović et al, 2004).
Of the total number of species found in Morača canyon 98% (127 species) has
either a national or international protection status, namely: 24 species are listed in Annex I of the EU Bird Directive, 67 Species are of European Conservation Concern (SPEC), 23 are Emerald species, 72 species are listed in Annex II of the Bern Convention, 46 in Annex II of the Bonn Convention, 14 species are listed in the CITES Convention and 7 species are listed in the African-Eurasian Waterbird Agreement (AEWA) (Errore. L'origine riferimento non è stata trovata.).
So far, 281 bird species have been registered in Skadar lake corresponding to 18 taxonomic orders or 51 families (Dhora, Saveljić, 2001). More than 30% of this number are wintering birds, and the same applies to passerines. More than 205 are breeding and only 11% of the recorded species are residents (Vasić, 1983). This clearly shows that 90% of total bird fauna on the Lake is mobile, i.e. it is not an exclusive ornithological asset of Montenegro but belongs to Europe, Asia and Africa. All species are fully protected due to the hunting ban enforced since 2001. According to the law on nature protection and the law on national parks, reserves are the littoral or marine areas with unchanged or slightly changed overall nature, they are intended only for conservation and/or non impacting scientific research, as well as monitoring of nature and education which are though required not to impact on natural processes. There are five nature reserves in Skadar lake (see Figure 5).
The study proved that Moraca canyon is an extremely important bird hotspot at national and regional level, more specifically: Ø 130 species were registered in Morača canyon; Ø 84 species breed in the canyon (confirmed by field survey); Ø 10 species most probably breed in the canyon (breeding not confirmed but
expected); Ø 29 of 52 species eligible for declaring an Important Bird Area of Montenegro
have been found in the canyon; Ø 127 species are protected, or 42% of the total number of protected bird species
in Montenegro; Ø 24 species are listed in the Annex I of the Bird Directive; Ø 67 species are Species of European Conservation Concern (SPEC) ; Ø 23 species are Emerald species according to the Bern Convention; Ø 72 species are listed in the Appendix II of the Bern Convention; Ø 36 species are listed in the Appendix III of the Bern Convention Ø 46 species are listed in the Annex II of the Bonn Convention; Ø 14 species are listed in the CITES Convention; Ø 7 species are listed in the African-Eurasian Waterbird Agreement (AEWA); Ø The canyon is habitat to app. 1600 species of vascular flora (50% of total
number of registered species in the country) ; Ø More than 60 Balkan endemic plant species are present; Ø More than 85 permanently protected plant species are present; Ø Mrtvica river canyon and Mala rijeka canyon (tributary of Moraca river) have
been declared Emerald sites, hence protected according to international
The ornithological reserves Pančeva oka and Manastirska tapija were the first nature reserves in Montenegro, declared in 1986 15 years before Skadar Lake was declared a national park. This clearly shows their natural value and importance for the protection of biodiversity. Later on, by decree, Omerova gorica, Crni žar and Grmožur were added to the list. All of them are located near the shore of the lake (Figure 5).
All reserves of the Skadar Lake national park have been designated zones of special interest for protection, primarily as breeding areas for birds.
Figure 5. Ornithological reserves on Skadar lake (G. Earth/ V. Bušković).
4.2. Predicted consequences of dams on the bird fauna and flora
The inundation of the canyon upstream of the dams would cause permanent loss of habitats for resting, reproduction and feeding of birds and would drastically change the qualitative and quantitative state of ornithofauna in the canyon. First of all, the species breeding in the cliffs and feeding in river streams or pebble excavation locations would vanish. In addition, the species breeding on high rocks and hunting in more open sections of the canyon such as eagles, hawks, owls, numerous songsters breeding in the river bed and in low vegetation or trees above water would vanish.
An example of the impact of habitat loss on birds and the consequent destruction of plant and animal life is the nearby river canyon beside Piva River and Pivsko Lake, where no birds can be found today due to loss of habitats.
Habitat loss and the change of vegetation cover due to change of microclimate will reflect on the composition of ornithofauna of these two canyons, already
acknowledged as valuable by the Council of Europe (being Emerald sites), namely Mrtvica River canyon and Mala rijeka canyon (tributaries of Morača ).
In the hydrological study for Morača river and Skadar lake carried out as part of the project Sharing Waters (Knežević, in prep) it is explained that the construction of the Hydro Power Plant Zlatica, with a dam approximately 75m high, will imply the creation of the Biocko reservoir. This reservoir is likely to “leak” water due to its karst terrain and several underground connections, which are unlikely to be closed even with serious cement injection works. This would significantly impact the levels of underground waters of the surroundings, possibly causing new swamps and vegetation and hence resulting in changes to the type of bird fauna. Additional hydro-geological information is needed for a more precise prediction of this phenomenon.
Another expected change, due to the construction of the hydropower plant Zlatica in Morača canyon, is the permanent impediment to sediment transportation through Morača canyon. This would significantly change the morphology of the waterbed. Zeta River in fact, the main tributary of the Morača , does not contribute with any sediment. Beside the fact that pebble islets would vanish, where Charadriiformes breed, like the most important breeder of Morača banks the Kentish Plover (Charadrius alexandrinus, listed in Annex I of the Bird Directive), many other negative impacts would occur. In particular the erosion of Morača river banks at the confluence with Skadar lake and the loss of the biggest breeding site of sand martin (Riparia riparia) in Zabljacke meadows (near the inflow of Morača river into Skadar lake). The level of erosion of the banks at the inflow of the lake and the number of flooded meadows that would be lost by flooding of Morača river will be massive.
Finally the entire northern lake shore, which during the summer months gets overgrown with key vegetation, is a breeding site of several birds species, which are very interesting from a scientific point of view and in high need of protection.
5. Fish fauna of Morača river and Skadar lake
This study has been based on literature data on fish of Morača river and Skadar lake as well as on the economic income deriving from fishery.
5.1. Fish fauna of Skadar lake and Morača river
According to Knežević (1981) the fish fauna of Skadar lake and its river system includes 17 families, 38 genus and 45 fish species. Marić (1995) emphasizes two newly- described species, Chondrostoma scodrensis and Rutilus prespensis vukovici. The latest literature adds three newly-described species: Pomatoschistus montenegrensis, (Miller & Šanda, 2007), Knipowitschia montenegrina, (Kovačić & Šanda, 2007) and Scardinius knezevici, (Bianco & Kottelat, 2005) reaching in total 50 fish species.
Of these 50 species, 31 are endemic with Adriatic-Ionian distribution. This means that 62% of species in Skadar lake system are endemic (
Figure 6). Of these 31 endemic species, 8 of them are endemic to Skadar Lake system, meaning that they live only in this water system, implying that 16% of ichthyic fauna is strictly endemic to this area.
Figure 6. Composition of Skadar lake fish fauna (Mrdack, in prep).
The most important fish species of Skadar lake system are, without any doubt, the endemic species but it is important to remark that the level of endemism varies (local endemic species, species that are endemic to the Adriatic-Ionian region, species that are endemic to the eastern Mediterranean). The second most important parameter is the level of threat to individual taxon according to the IUCN red list classification, and the third parameter is the size of Skadar lake system compared to the distribution range of each endemic species.
SPECIES - SUBSPECIES IUCN Red List Category Salmothymus obtusirostris zetensis EN B2ab Leuciscus souffia montenegrinus LR/lc Phoxinellus stimphalicus montenegrinus no data Scardinius knezevici no data Acipenser naccarii VU A1ac Acipenser sturio CR A2d Allosa fallax nilotica DD Salmo dentex DD Salmo marmoratus LC Alburnoides bipunctatus ohridanus LR/lc Alburnus alburnus alborella no data Barbus peloponnesius LC Chondrostoma nasus ohridanus LR/lc Pachychilon pictum LC Rutilus basak ohridanus LC Scardinius erythrophthalmus scardafa CR A3e Barbatula barbatula sturanyi LR/lc Padogobius panizzai LC
Figure 7. List of most important endemic fish species of Skadar lake and IUCN conservation status. List of categories available at http://www.iucnredlist.org/info/categories_criteria1994 - categories.
Non-endemic species 12%
Endemic for Adriatic – Ionian region
Endemic for Skadar lake 16%
Introduced species 26%
5.2. Commercial fish stock and its economy
The fish resources of Skadar Lake represent more than 95% of the total fresh water fishery in Montenegro. In terms of fish production and fish biomass Skadar lake is far from other karst lakes on the Balkan peninsula being in fact much higher. Based on statistical data of yearly catches, fish production in Skadar lake is 80 kg/ha (8000 kg/km2, data related to the Montenegrin part of lake) (Drecun, 1983). This level of fish production compares Skadar lake to eutrophic lakes fish production while Skadar lake is actually oligotrophic. As in other large-surface lakes, only a restricted number of fish species dominate in normal fish production and represent most of the catch in the lake. Carp (Cyprinus carpio) and bleak (Alburnus alburnus alborella) represent more than 70% of the total catch. Beside these two species, Alosa fallax nilotica, Anguilla anguilla, Chondrostoma nasus, Leuciscus cephalus albus, Scardinus erythrophtalamus scardafa, Rutilus basak ohridanus, Mugil cephalus are also caught in the lake (Table 1).
Species - subspecies English name Alburnus alburnus alborella Adriatic bleak
Cyprinus carpio Carp Alosa fallax nilotica Shad Anguilla anguilla Eel
Table 1. List of fishery species of Skadar lake (Mrdak D. et al. 2003)
The study estimated that at least 300 families directly depend economically on
the fish stock as their main income. An additional 300 families depend indirectly on fishery activity, so a realistic estimate is about 600 families who depend on fish as their main income-generating resource.
The whole economy based on fish as a main resource (fishing, fish processing,
restaurants, sport fishing) is worth at least 4,250,000 € per year. The potential decrease of income based on fish resource is proportional to the
decrease of fish resource. As a consequence, since a decrease of 30% of the carp population is expected this will impact by 30% the annual income derived on carp fishery. The loss estimated is expected to be of approximately 1.416.666 €.
5.3. Predicted consequences of dams on fish The study made by Knežević (in prep.) predicts the consequences of variation
in an important ecological requirement of fish, the spawning habitat. It is widely known that the most vulnerable part of the year for all fish species is the spawning period. In Skadar lake, predominantly inhabited by Cyprinids, this occurs in spring when natural floods occur. Of the two most important fishery species, carp and
bleak, the carp uses a special and temporary habitat for spawning, created by spring flood events, so that the carp migrates from the deeper water habitats in the lake into the shallow flooded areas that are overgrown by macrophytic vegetation. In these temporary habitats they gather in massive groups, spawn and leave fertilized eggs in the submerged vegetation. After spawning they return to the lake while their larva stay in pools, channels and small lakes to grow. Kneževic (in prep) calculated that if water is loaded in dam reservoirs during spring months (April, May and June) this will cause a decrease in the water level of Skadar lake in April of approximately 63cm, meaning that the lake’s surface will decrease by 12.6km2. The lost surface corresponds to the spawning ground for carp. The data for May and June are similar: in May the water level will decrease by 64cm causing a decrease in lake surface of 12.8km2 , while in June the water level will decrease by 65cm which will result in a decrease of the lake surface of 15.8 km2. If this happens the fertilized eggs or the carp’s larva would perish.
It is estimated that 20% of spawning ground will be destroyed resulting in
20% fewer juveniles in the next carp generation. This is a significant loss which, if it occurred every year, would result in a decrease, in 3 -10 years, of almost 20% of the total carp biomass of Skadar Lake. The bleak population on the other side is not expected to face the same direct impacts because of a different life cycle. The bleak, in fact, spawns in open waters and their larva are pelagic hence it will not suffer littoral habitat loss.
It is important to mention an indirect impact of dam building. This is related to
the expected changes in the physiology of Skadar Lake’s ecosystem. Morača river is a highly erosive river that feeds Skadar Lake with nutrients (phosphorus and nitrogenous soils). Considering that Morača river brings the majority of the lake’s nutrients (crucially important for the unusually high productivity of the lake) we can expect that some significant part of them will be stored in the new artificial reservoirs without ever reaching the lake. In other words Skadar lake will receive a significantly smaller amount of nutrients which would change the lake’s physiology and lower its bio-production. This loss will impact on all living components but in particular on the bleak as its larva live in free water and feed on zooplankton (bio-production). The bio-production is related to the plankton algae which are the main productive component of the lake ecosystem. Zooplankton, as an animal component, most directly depends on phytoplankton (algae) while for algae nutrients are one of the most restrictive needs. The decrease of bio-production will affect the bleak larva and consequently the bleak population. The exact extent of this decrease is hard to estimate. We do not know the amount of nutrients that can be expected to be deposited in the reservoirs and this makes it very difficult to accurately predict the decrease in Skadar lake production. A rough conservative estimate predicts a 10% decrease in the bleak population of Skadar lake.
As the dams on Morača river will be installed in the medium course we can
expect a strong negative impact on the trout population living there. Brown trout, the most abundant trout species, will face population fragmentation. In the upper part of the river (downstream of the dams) brown trout individuals will be isolated and the genetic diversity survival will rely on isolated individuals. Upstream and downstream migrations occurring every year will be restricted to the upper and lower areas separately. The brown trout from the lower stretch will lose spawning ground which is located in the upper part of the drainage which will be unreachable due to the dams. We can hence expect a decrease in their number which can increase again
only if they adapt and find new suitable spawning habitats. The middle course where the dams will be placed will be directly destroyed and will become an artificial lake ecosystem. Brown trout will be likely to inhabit those lakes but in drastically smaller numbers and they will be forced to adapt to the new reservoir habitats which may not be suitable. We can expect that they will face big constraints in spawning because no fast-flowing water with gravel bottom will be present (the habitat required for their spawning).
The marble trout will be also negatively affected because the medium course
of Morača river, where this species is more abundant, will be completely changed. We can expect that the number of marble trout individuals will dramatically decrease and this is of particular concern as the species is already at a critically low number compared to 25 years ago. As the middle course of Morača river is the main spawning ground for marble trout in Morača river, their number will suffer due to small spawning efficiency.
The brown trout could potentially survive in two separate populations
(upstream and downstream of the dams) while marble trout will remain only in the lower course (from Skadar lake till the first dam on Zlatica).
The three studies commissioned by WWF and Green Home show clearly that the construction of dams on Morača river will have a direct impact on Morača river natural values and an indirect impact on the natural values of Skadar lake as well as its fishery economy.
The construction of dams on Morača river should be carefully evaluated to
assess whether they are the best possible options (cost effective and less environmentally and socially damaging) as their construction will have an impact on important sites designed under the Bern Convention (Emerald sites) and on the economy of local populations just to mention the most striking impacts.
Currently a Strategic Environmental Assessment is on going and it is
expected (in compliance with article 5.1 of the EU SEA Directive) to look at alternative options as well. If the SEA will prove that the Morača dams are the best possible option (hence cost effective and not too environmental damaging) then it is imperative that the Environmental Impact Assessment should look at local and downstream impacts and plan mitigation measures to ensure the least possible damage.
7. Literature Bianco, P.G. i M. Kottelat. (2005). Scardinius knezevici, a new species of rudd from Lake
Skadar, Montenegro (Teleostei: Cyprinidae). Ichthyol. Explor. Freshwat. 16(3):231-238.
Dhora, D., Saveljić, D. (2001): Bibliography and check list on Shkodra/Skadar lake. Section VII – Ornithology – Birds. Promotion of networks and exchanges in the countries of the South Eastern Europe. - REC & SDC, Podgorica & Shkodra.
Kneževic Mirko. (in prep). Water regime of Skadar lake and simulated impact of Morača dams on its fluctuation. Report for WWF Mediterranean Programme Office, Rome.
Kovačić, M. and R. Sanda. (2007). A new species of Knipowitschia (Perciformes: Gobiidae) from southern Montenegro. J. Natl. Mus. (Prague), Nat. Hist. Ser. 176(5):81-89.
Miller & Sanda (2008). A new West Balkanian sand-goby (Teleostei: Gobiidae). Journal of Fish Biology 72 (1): 259-270.
Mrdak D., Joksimović J., Simonović P. (2003). Sustainable fishery basis for Skadar Lake- First phase. NGO Hidroekology of Montenegro.
Puzović, S., Simić, D., Saveljić, D., Gergelj, J., Tucakov, M., Stojnić, N., Hulo, i., Ham, i., Vizi,O., Šćiban, M., Ružić, M., Vucanović, M., Jovanović, T. (2004). Ptice Srbije i Crne Gore – veličine gnjezdilišnih populacija i trendovi:1990-2002. Ciconia 12, 36-120.
Radulović, V. (1997).Vode Skadarskog jezera i okolnih izdani kao izvorišta za vodosnadbijevanje, CANU 44, Podgorica.