Lake management in Italy
Transcript
Lake management in Italy
Lakes & Reservoirs: Research and Management 2003 8: 41–59 Lake management in Italy: the implications of the Water Framework Directive G. Premazzi1*, A. Dalmiglio2, A. C. Cardoso1 and G. Chiaudani3 1 2 Institute for Environment and Sustainability, European Commission, Joint Research Centre, 21020, Ispra, Italy, Agenzia Regionale per la Protezione dell’Ambiente della Lombardia, Regione Lombardia, 20100, Milan, Italy, and 3 Biology Department, University of Milan, 20100, Milan, Italy Abstract This paper constitutes the first consideration of the implications of the lake management in Italy arising from the requirements of the Water Framework Directive (WFD), in comparison to the provisions of existing national legislation. As a matter of fact, the Italian decrees anticipated the principles of the WFD and have substantially modified the legislation in the field of water in Italy. Important changes were introduced, both in the monitoring systems and in the classification methods for surface waters. The environmental quality status will be determined not only by monitoring the aqueous matrix, but also the sediment and the biota. The new WFD is the major piece of European Union (EU) legislation with environment at its core; it will guide the efforts for attaining a sustainable aquatic environment in the years to come. In the WFD one can see elements from all the different forces that guided the reform of EU water policy: environmental protection, deregulation and subsidiarity. Moreover, elements of the economic instruments approach (introduction of the cost recovery principle), quantitative concerns (setting of minimum flow objectives for rivers and abstraction limits for ground waters) and the quest for integration (river basin management with representation of all stakeholders) are all reflected in the WFD. The paper summarizes the present condition of the most important lakes in the Italian lake district and also highlights the case of Lake Varese, representing a unique case of lake management in Italy. Preliminary results show that there are very few examples dealing with the elements thought appropriate to lake water assessment as required by the WFD. The application of the objectives of the type specified is a largely unknown issue. Key words ecological water status, European Union Water Framework Directive, Italian water legislation, lake management, subalpine lakes. BASIC LEGAL FRAMEWORK FOR WATER QUALITY PROTECTION IN ITALY In Italy the regions are charged with water monitoring activities and the central government is empowered with supervision, coordination and regulation tasks. The basic legal framework for water quality protection and monitoring is established by: 1. Legislative decree number 152/99, which transposes the European Union (EU) Directives 91/271/EEC and 91/676/EEC, and defines the main requirements for water quality monitoring in inland waters, coastal waters, estuaries and lagoons (Decreto Legislativo 1999). *Corresponding author. Email: [email protected] Accepted for publication 29 November 2002. 2. Legislative decree number 258/00 (Decreto Legislativo 2000), which concerns the protection of water from pollution and integrates thoroughly some topics of the legislative decree 152/99 (Decreto Legislativo 1999). For the first time in Italy, the two decrees set environmental and functional objectives for water bodies. 3. Law 183/89 (Repubblica Italiana 1989) which establishes river basins as the unit where environmental protection activities have to be designed and performed, and creates river basin authorities. 4. Law 36/94 (Repubblica Italiana 1994a) which concerns the reorganization of the public services that are charged with water abstraction, water supply and distribution, and waste water treatment. 5. Law 61/94(Repubblica Italiana 1994b) which relates to the reorganization of environmental controls and the 42 G. Premazzi et al. Table 1. Classification of the lakes’ ecological status† Parameters Transparency (m) Hypolimnetic oxygen (% saturation) Chlorophyll (µg/L) Total phosphorus (µg/L) CLASS 1 CLASS 2 CLASS 3 CLASS 4 CLASS 5 (high) (good) (moderate) (poor) (bad) >5 5 2 1.5 1 >80 80 60 40.0 20 <3 6 >10 25.0 >25 <10 25 50 100.0 >100 † See Decreto Legislativo (1999). Table 2. The main chemical compounds monitored in surface inland waters† Inorganic Organic cadmium aldrin total chromium dieldrin mercury endrin nickel isodrin lead DDT‡ copper hexachlorobenzene zinc hexachlorocyclohexane hexachlorobutadiene trichlorobenzene chloroform perchloroethylene pentachlorophenol tetrachloromethane trichloroethylene 1,2 dichloroethane † See Decreto Legislativo (1999); ‡DDT, 1, 1, 1 trichloro-2, 2 bis (4-chlorophenyl) ethane. National Agency for Environmental Protection and Regional Agencies A reorganization of the administrative system for river management has recently taken place in Italy, partly as a result of recognition of the growing importance of taking an integrated approach to environmental management. River basin authorities have been set up covering six basins of national importance (the largest and most important one is that of the Po River), as well as 15 regional and 17 interregional basins. The responsibility for environmental protection and monitoring has been largely devolved from the national level to the regions, provided that the minimum requirements of the national legislation are satisfied. The design of monitoring programmes is undertaken at the local level, on a case-by-case basis. The range and extent of programmes may vary but local monitoring can be divided into different categories, such as trend detection and general quality characterization, discharge (point and diffuse) impact assessment and post-pollution incidents. Both of the decrees anticipated the principles of the EU Water Framework Directive (WFD) (European Communities 2000) and have substantially modified the legislation in the field of water in Italy. Important changes were introduced, both in the monitoring systems and in the classification methods for surface waters. The environmental quality status will be determined not only by monitoring the aqueous matrix, but also the sediment and the biota, the latter intended both as accumulator of harmful substances and recorder/integrator of environmental pressures. The new monitoring system consists of two steps: a cognitive phase and a full operational phase. In the first phase (two-year duration), general information should be gathered regarding surface water bodies, in order to be acquainted with the lake and its environmental conditions (for example, pressures from the catchment). This evaluation will permit the establishment of a monitoring plan, and thus, the definition of the minimum number of sampling points (depending on the lake size), the identification of the criteria for selection of the sampling location and the sampling frequency. All lakes with a surface area 0.5 km2 should be monitored. For lakes with a surface area <80 km2, the sampling point coincides with that of the maximum depth of the water body. However, by default, in the absence of bathymetric maps, it could be located at the centre of the lake. For lakes with a surface area >80 km2 or of irregular configuration (for example, forming bays or arms), the sampling points are fixed on a case-by-case basis. In each of the fixed sampling stations, chosen with respect to the desired information and in conformity to local conditions, at least three sampling depths should be considered: 1 m from the lake surface, 1 m above the lake bottom and a depth in the middle of the water column. For shallow lakes (z max 5 m) the number of samples within the water column are reduced to two (surface and bottom). For lakes deserving particular protection and safeguarding, the sampling profile should be much more detailed. As an example, the monitoring programme undertaken in the deepest Italian lake, Como, Italy’s Water Framework Directive 43 intended as a strategic water body for the abstraction of drinking water and of particular environmental value, includes six different stations for a total of 62 sampling depths; only the water column at the maximum depth (410 m) is described by 12 sampling depths. The operational phase indicates that monitoring programmes could take place at a reduced frequency and at a limited number of sampling stations for only basic (mandatory) quality elements, if the surface water bodies concerned reach good/high status and there is no evidence that the impacts on the water bodies have changed. As concerns the classification of the lake quality status, the allocation of a lake to a certain environmental class will be done by referring to the ecological and chemical status. A series of relevant quality elements are used for the definition of the ecological status of lakes: these are mainly ascribable to eutrophication. They include the following physicochemical and chemical elements: • Transparency (minimum annual value) • Hypolimnetic oxygen saturation (minimum annual value during stratification) • Chlorophyll a (maximum annual value) • Total phosphorus (P), (maximum annual value) The classification of the ecological status shall be represented by the worst of the values from the monitoring results of the quality elements. The assignment to the appropriate water status will be done using the following class boundary numerical scale (Table 1). The chemical status is defined as that exceeding (or not) the threshold limits for some micropollutants and hazardous substances, defined on a catchment basis for a reference water body. The list of the main chemical compounds to be monitored in surface inland waters is shown in Table 2. The limit values and quality objectives established under the five daughters directives of Directive 76/464/EECdangerous substances (European Communities 1976)-will consider emission limit values and environmental quality standards, respectively, in the evaluation of the chemical status for lakes. Arithmetic mean values are considered for the classification. Therefore, the environmental status of a surface inland Table 3. water body shall be determined by its ecological and chemical status, and classified accordingly to the five classes set out in Table 3. BASIC FEATURES OF THE WATER FRAMEWORK DIRECTIVE The new WFD is the major piece of EU legislation with environment at its core and it will guide efforts for attaining a sustainable aquatic environment in the years to come. The WFD is based on a ‘framework philosophy’ in line with the principle of subsidiarity. It sets only the objectives to be fulfilled by member states (for example, good water quality), and defines the organizational structure (river basin authorities) and mechanisms (existing legislation and further measures) to achieve them. As such, the WFD best exemplifies the new approach in the EU environmental policy, where environmental protection is married with subsidiarity through the division of objectives at a European level and standards/measures at a national level. The WFD will also replace many of the ‘first waves’ legislation such as the directive on surface water for drinking waters abstraction (European Communities 1979a) and the fish and shellfish water directives (European Communities 1979b). This satisfies the call for deregulation (simplification) of the existing legislative framework. On the other end, the European Commission considered that the public health standards (such as those of the drinking and bathing directives) should not be affected (European Commission 1996). In the WFD one can see elements from all the different forces that guided the reform of EU water policy, that is, environmental protection, deregulation and subsidiarity. Moreover, elements of the economic instruments approach (introduction of the cost recovery principle), quantitative concerns (setting of minimum flow objectives for rivers and abstraction limits for ground waters) and the quest for integration (river basin management with representation of all stakeholders) are all reflected in the WFD. A number of new strategies will result from the implementation of the WFD. Specific issues that are important in formulating a sectorial strategy include the following: Classification of the environmental status of surface inland water bodies† Ecological status CLASS 1 CLASS 2 CLASS 3 CLASS 4 CLASS 5 Threshold value HIGH GOOD MODERATE POOR BAD > Threshold value POOR POOR POOR POOR BAD Micro-pollutants and hazardous substances concentrations, as per Table 2 † See Decreto Legislativo (1999) 44 G. Premazzi et al. Table 4. Comparison between the provisions in the Italian legislation and in the Water Framework Directive regarding determination of the lakes’ ecological status Decreto Legislativo number 152 (5/1999)†, Decreto Legislativo number 258 (8/2000)‡ Goals To prevent and limit pollution; to restore polluted water bodies; to enhance the status of all water bodies; to ensure adequate protection of those intended for particular uses; to promote sustainable use of water resources, with priority for those water bodies intended for abstraction of drinking water; to maintain the natural self-depuration capacity of water bodies What to monitor Natural lakes with surface area 0.5 km2 Artificial lakes with surface area 1 km2 or lake volume 5 106 m3 Sensitive lakes at altitude <1000 m (Urban Waste Water Treatment Directive) and surface area 0.3 km2 Quality indicators Water: Mandatory parameters: temperature, pH, transparency, conductivity, alkalinity, dissolved oxygen, hypolimnetic oxygen (% saturation), chlorophyll a, total phoshorus, soluble reactive phosphorus, total nitrogen, nitrate, nitrites, ammonia Additional parameters: 7 heavy metals, 15 organic micro-pollutants Sediment: Additional parameters: 8 heavy metals, polychlorinated biphenyls, polycylic aromatic hydrocarbons, TCCD,tetrachlorodibenzo-p-dioxin; organochlorinated pesticides Bioassays: on pore water and wet sediment using Daphnia magna, Selenastrum capricornutum, Chironomus tentans Biota: Bioassays: toxicity tests with Daphnia magna, mutagenetic and teratogenetic tests, algal tests, bioaccumulation of polychlorinated biphenyls, DDT¶ and cadmium on autochthonous fish and macrobenthos Sampling Number of stations: for lake surface <80 km2, 1 at maximum depth for lake surface >80 km2 or of irregular configuration, 1 + n Sampling depth: lakes with zmax 5 m (2) lakes with zmax 50 m (3) lakes with zmax >50 m (5 + n) lakes of particular environmental value (7 + n) Frequency: twice per year (winter circulation and summer stratification) Classification of water status Ecological status (trophic status): five classes from high to bad; allocation as the lowest value of the relevant quality elements (transparency, hypolimnetic oxygen, chlorophyll a, total phosphorus) Environmental status: a combination of the above ecological status with the chemical status, evaluated by the heavy metals and organic micro-pollutants contents and the bioassays results. 5 classes from high to bad, if the micro-pollutants concentration is less than or equal to threshold level. Two classes (poor and bad), if the micro-pollutants concentration is greater than threshold level Directive 2000/60/EC of 22 December 2000§ Goals To achieve sustainable management; to maintain the ecosystem’s functioning (including dependent wetlands and terrestrial ecosystems); to reach good ecological status What to monitor lakes with a significant volume within a river basin district and significant trans-boundary lakes (surveillance monitoring) lakes representative of the risk or overall impact of the pressures in the river basin district (operational monitoring) lakes failing to achieve environmental objectives (investigative monitoring) natural and artificial lakes with surface area 0.5 km2 Italy’s Water Framework Directive 45 River basin management Combined approach The new approach to water management requires water to be managed on the basis of river basins, rather than according to geographical or political boundaries. This enables assessment of all activities which may affect the watercourse, and their eventual control by measures which may be specific to the conditions of the river basin. The WFD requires river basin management plans to be drawn up on a river basin basis. It may be necessary to subdivide a large river basin into smaller units, and sometimes a particular water type may justify its own plan. Basically, two different approaches to tackle water pollution exist at European (member state) level: • limiting pollution at the source by setting emission limit values (ELV) or other emission controls • establishing water quality objectives (WQO) for water bodies The WFD is based on a combined approach where ELVs and WQOs are used to mutually reinforce each other. In any particular situation, the more rigorous approach will apply. This combined approach is also in accordance with principles established in the treaty (European Communities 1997). For example, the precautionary principle, which suggests that environmental damage should, as a priority, be rectified at the source and that environmental conditions in the various regions shall be taken into consideration. Programme of measures Central to each river basin management plan is a programme of measures to ensure that all waters in the river basin achieve good water status. The starting point for this programme is the full implementation of any relevant national or local legislation as well as of a range of EU legislation on water and related issues. If this basic set of measures is not enough to ensure that the goal of good water status is reached, the programme must be supplemented with whatever further measures are necessary. These might include stricter controls on polluting emissions from industry or agriculture and urban waste water sources In this context, land use planning might be a key issue to be taken into account. Table 4. Monitoring programme Monitoring is an essential part of the implementation of the WFD. Such systematic monitoring of surface water and groundwater quality and quantity can be categorized as: 1. Surveillance monitoring, which is undertaken to provide information on the status of water, to identify its initial condition and to assess long-term changes, both from natural and anthropogenic activities, in the catchment basin. (continued) Quality indicators Biological elements: composition, abundance and biomass of phytoplankton; composition and abundance of other aquatic flora and benthic invertebrate fauna; composition, abundance and age structure of fish fauna Hydromorphological elements: hydrological regime (quantity and dynamics of water flow, residence time connection to groundwater body); morphological conditions (lake depth variation, quantity, structure and substrate of lake bed; structure of lake shore) Chemical and physicochemical elements: general (transparency, thermal conditions, oxygenation conditions, salinity, acidification status, nutrient conditions); specific pollutants (all priority substances discharged into the body of water, pollution by other substances identi fied as being discharged in significant quantities into a water body) Sampling Frequency: Surveillance monitoring: for each monitoring site; at least for one year if covered by a river basin management plan Operational monitoring: frequency to be determined by member states, so as to provide sufficient data for reliable assessment of the status of the relevant quality element. The table in Annex V, paragraph 1. 3. 4. gives some frequency guidelines. For example, the physicochemical elements should be monitored every 3 months, with the exception of the priority substances (monthly); the biological elements should be monitored every 3 years, with the exception of phytoplankton (every 6 months) Classification of water status Ecological status: five classes from high to bad (table in Annex V, paragraph 1. 4. 2.); the status of quality is identified as the lower of the values for the biological and physicochemical monitoring results Chemical status: two classes, good and failing to achieve good; good indicates compliance with all water quality standards as established in Annex IX, article 16 † See Decreto Legislativo (1999); ‡see Decreto Legislativo (2000); §see European Communities (2000). ¶ DDT, 1,1,1 trichloro-2,2 bis (4-chlorophenyl) ethane. 46 G. Premazzi et al. Italy’s Water Framework Directive 2. Operational monitoring, which is undertaken to assess the success, or otherwise, of measures enacted to improve the situation. 3. Investigative monitoring, which is undertaken in problem areas where an accidental pollution has occurred or where the causes of a problem in meeting environmental objectives is not known. Data on monitoring is publicly available, and also forms the basis for regular reporting to the European Commission, as well as contributing to the monitoring network within the European Environment Agency. Cost recovery The application of economic instruments such as charges for use of water as a resource or for the discharge of effluents into watercourses is a policy explicitly endorsed in the new directive. The ‘polluter pays’ principle must be applied, and economic assessment becomes an essential part of water management planning. The principle of charges for water reflecting true costs is a radical innovation at European level. There is a danger in this proposal that water may become too expensive a commodity for many, and a general reduction in its beneficial use may result. Public consultation The WFD requires consultation to take place and the relevant authorities should arrange consultation mechanisms with the interested parties such as the general public, non-government organizations, farmers and water companies. In this context, consultation with all relevant parties might achieve a best cost-effectiveness and identify the best combination of measures on a proportionate level. Therefore, preparation of those parts of the WFD addressing information and consultation of all stakeholder groups and the public, should be subject to serious efforts. Integration of stakeholders and the civil society in decision making, by promoting transparency and information to the public and by offering a unique opportunity for involving stakeholders in the development of river basin management plans, is a central concept of the WFD. Fig. 1. Map of the Italian lake district (Passino et al. 1999). Area, 71 057 km2; Regions, Piemonte, Valle d’Aosta, Lombardia, Veneto, Liguria, Emilia-Romagna, Provincia Autonoma di Trento; Population, 16 000 000; head of cattle, 4 188 000; head of pigs, 5 232 000; maximum population density (Lambro area), 1478 inhabitants (ab)/km2; minimum population density (Trebbia valley), 25 (ab)/km2; groundwater abstractions, 5.3 109 m3/year; surface water abstractions, 25.1 109 m3/year. 47 The comparison of the provisions, considered by the legislative decrees and the WFD, for the determination of the ecological status of lakes, is reported in Table 4. THE PRESENT CONDITION OF THE MOST IMPORTANT LAKES IN THE ITALIAN LAKE DISTRICT In Italy there are more than 2000 lakes. Of these, 389 are freshwater (natural, enlarged natural and reservoirs) and 104 are coastal with brackish water, excluding lagoons. One hundred and forty seven of these aquatic environments (87 lakes and 60 reservoirs) have been classified according to Organization for Economic Cooperation and Development criteria. P is the main substance responsible for the eutrophication process because it was identified as the limiting factor in 85% of examined lakes. Only 19% of lakes and reservoirs are in oligotrophic conditions, 40% are classified as mesotrophic and 41% as eutrophic. Among these, 10% are considered to be hypertrophic (Ministry of the Environment 1997). The most important Italian lake district is located in northern Italy and includes the deep subalpine lakes and some small-medium insubrian lakes (Fig. 1). Together these represent more than 80% of the total Italian lacustrine volume. Hereinafter, it is intended to summarize the state-of-theart knowledge of the selected Italian subalpine lakes Como, Garda, Iseo, Maggiore and Varese. In particular, focus has been placed on those parameters directly linked to the lake trophy (nutrients) and on some biological elements (phytoplankton, zooplankton and fish) in view of the implementation of Decreto Legislativo number 258/00 (Decreto Legislativo 2000) and the WFD. The case study of Lake Varese is highlighted because it represents a case of lake management which is unique in Italy, in which lake restoration technology is applied to accelerate the return to earlier (more natural) conditions, after being impacted by eutrophication. General characteristics Table 5 summarizes the main morphometric and hydrologic characteristics of the lakes Como, Garda, Iseo, Maggiore and Varese. According to the Consiglio Nazionale delle Ricerche Istituto di Ricerca sulle Acque (1984), Lake Como (or Lario) is the deepest Italian lake and the third in terms of surface area and volume, after lakes Garda (or Benaco) and Maggiore (or Verbano). Its drainage basin occupies an area of 4552 km2, of which 487 km2 is in the Swiss territory. The particular shape of the lake forms three distinct sub-basins: the western basin (Como), the eastern basin (Lecco) and an upper basin. 48 G. Premazzi et al. Lake Varese is a relatively small Insubrian lake, belonging to the catchment area of Lake, Maggiore. It has had a long history (since the 1960s) of water quality deterioration as the result of cultural eutrophication. Its catchment basin is one of the most densely populated areas in Italy (up to 700 inhabitants/km2) and is associated with many industrial and commercial activities. It is the first example in Italy of the use of in-lake methods to counteract the problems caused by excessive nutrient enrichment. The rainfall regime has the typical behaviour of alpine areas, with concentration of precipitation between May and November. Approximately 70–75% of the mean annual precipitation volume (1200 mm/year for Lake Garda, 1800 mm/year for Lake Maggiore) is concentrated in this period. Lake Garda (Benaco) is the largest Italian lake with a surface area of 368 km2 and it is located 65 m a. s. l. (lower altitude by comparing with the other Italian subalpine lakes). Lake to drainage area ratio is about 1/6, lower in respect to that of other lakes (≈ 1/30). Two sub-basins can be distinguished. Lake Iseo (or Sebino) is the fourth Italian lake with a surface area of 60.9 km2. A specific feature is that it includes the largest European lacustrine island (area, 4 km2; height, 414 m). Lake Maggiore (Verbano) is the second Italian lake in terms of surface area and volume. Its drainage basin occupies an area of 6600 km2, of which 50% is in the Swiss territory. Yet 80% of the lake surface is in Italian territory. Table 5. Main morphometric and hydrological characteristics of the subalpine lakes Como, Garda, Iseo, Maggiore and Varese† Parameters Como Garda Iseo Maggiore Varese Latitude N 4610 4540 4544 4547 4548 Longitude E (G)‡ 0916 1041 1004 840 845 Drainage area (km ) 4522 2260 1736 6599 111.50 Lake area (km2) 145 368 60.9 212 14.52 Lake volume (106 m3) 23 372 49 030 7569 37 500 153 Lake volume (106 m3) (w. basin)§: 9435 45 766 – – – 2 6 3 ¶ Lake volume (10 m ) (e. basin) : 3702 3264 – – – Lake volume (106 m3) (u. basin)††: 10 236 – – – – Theoretical renewal time (year) 4.5 26.6 4.1 4 1.90 (w. basin): 10.8–14.5 (w. basin): 29.6 – – – Effective renewal time (year) (e. basin): 3.7–6.5 (e. basin): 2.1 – – – Effective renewal time (year) (u. basin): 7.1–9.7 – – – – Effective renewal time (year) (lake): 10.4–12.8 – 15–18 14.5 2.80 410 350 258 370 26 Mean depth (m) 161 133 122 177 10.70 Mean lake level (m a. s. l) 198 65 186 194 238 Outflow discharge (m3/s) 158 (18–918) 58.4 (10–200) 58.9 (15–446) 298 (100–500) 2.9 (1.2–4.8) Effective renewal time (year) Maximum depth (m) † See Rossi & Premazzi (1975); Rossi & Premazzi (1991); ‡G, Greenwich. §w, western; ¶e, eastern; †† u, upper. Fig. 2. The evolution of the average dissolved oxygen concentration in the hypolimnetic waters of lakes Como, Garda, Maggiore and Iseo (Regione Lombardia–Commissione Europea 1997; Commissione Internazionale per la Protezione delle Acque Italo-Svizzere 2001). , Como; , Garda; , Maggiore; , Iseo. Italy’s Water Framework Directive Lake water characteristics: temperature and oxygen Two hydrodynamic characteristics are of most importance in the deep subalpine lakes, the water renewal time and the vertical mixing. The effective mean residence time was evaluated in all subalpine lakes because this parameter is included in eutrophication models and its consideration is indispensable in lake restoration. For Lake Maggiore, the mean water renewal time has been estimated to be 14.5 years by Piontelli and Tonolli (1964). Other lake renewal times were estimated by Rossi and Premazzi (1975), Chiaudani et al. (1986), Rossi and Premazzi (1991) and Rossi (1991), as reported in Table 5. The second important hydrodynamic feature of these great lakes is their specific holo-oligomixis. An analysis of the thermal profiles suggests that these water bodies can be considered as oligomictic basins with a winter circulation (January–March) and summer stratification (June–October). However, a complete homogenization of the waters is only found in the shallower basins with average temperatures ranging from 5.5°C to 6.8°C. The lake volume affected by mixing varies from 40% to about 70% of the total volume. The complete overturn can only occur in conjunction with particularly cold and windy winters. The mixing depths in these lakes ranged from a minimum of 50 m to a maximum of 250 m. For example, in Lake Maggiore in the past 50 years, only four complete overturns (1956, 1963, 1970, Fig. 3. The evolution of the average total phosphorus concentration during spring circulation in the lakes Como, Garda, Maggiore and Iseo (Regione Lombardia– Commissione Europea 1997; Commissione Internazionale per la Protezione delle Acque Italo- Svizzere 2001). , Como; , Garda; , Maggiore; , Iseo. Fig. 4. The evolution of the average total mineral nitrogen concentration during spring circulation in the lakes Como, Garda, Maggiore and Iseo (Regione Lombardia–Commissione Europea 1997; Commissione Internazionale per la Protezione delle Acque ItaloSvizzere 2001). , Como; , Garda; , Maggiore; , Iseo. 49 1999) have occurred. In Lake Iseo since 1981, no full circulation occurred and the volume affected by mixing is less than 50% of the total lake volume. The deepest basin of this lake would be considered at risk of meromixis, and consequently, noticeable chemical differences exist between the upper 80 m of the water column (mixolimnion) and the deepest layers. Thus, two different values should be necessary to describe the chemical conditions of the lake (Premazzi et al. 1998). The evolution of the average dissolved oxygen concentration in the hypolimnetic waters of the lakes Como, Garda, Maggiore and Iseo is represented in Fig. 2. Dissolved oxygen is roughly present between 6 mg and 9 mg O2/L. Despite the partial overturn of the waters, anoxic conditions were never observed in the bottom layers where oxygen saturation values fluctuated from 20% to 60%. The exceptions are Lake Iseo, where in the deepest basin (below 200 m) anoxic conditions were registered, and Lake Varese, where from June to October anoxic conditions are measured in about 60% of the lake volume. In the epilimnion of all these lakes, typical conditions of over-saturation (110–140%) are observed during the summer months, when primary production is the highest. The oxygenation conditions of the lakes Iseo and Varese would be considered unsatisfactory and typical of highly productive, eutrophicated environments (Ambrosetti et al. 1992; Mosello et al. 1997; Premazzi et al. 1998; Premazzi 2002). 50 G. Premazzi et al. Nutrients and chlorophyll meters, causal elements, and one response parameter, chlorophyll concentration (Cardoso et al. 2001). The evolution of the average concentration of total P and of the average concentration of total mineral N in the lakes Phosphorus and nitrogen (N) are the main culprits of cultural eutrophication in freshwaters. Thus, the deviations from a trophic level can be assessed with these two para- Table 6. Chlorophyll a concentration, cell density and biomass of phytoplankton in the epilimnion of the lakes Como, Garda, Iseo, Maggiore and Varese† Parameters Como Garda 5.4 4.5 Iseo Maggiore Varese Density (106/L) Mean 6.0 – 5.4 Minimum 0.3 0.2 0.1 – 0.2 Maximum 18.0 13.0 30.0 – 21.0 544.0 519.0 1558.0 Biomass (mg/m3) Mean 960 6654.0 Minimum 48.0 100.0 234.0 200 300.0 Maximum 2031.0 1500.0 6451.0 2800 36 000.0 45.0 46.0 38.0 76–80 30.0 Mean 5.4 4.0 7.4 2.9 12.0 Minimum 0.8 0.5 0.7 0.5 1.0 Maximum 11.0 12.0 28.6 5.6 61.0 Species number Chlorophyll (mg/m3) † See Commissione Internazionale per la Protezione delle Acque Italo-Svizzere (2001); Premazzi (2002); Dalmiglio (unpubl. data). Table 7. Zooplankton density and composition in the 0–50 m layer of the lakes Como, Garda, Iseo and Maggiore† Como Garda Iseo Maggiore mean – – – 3.00 minimum – – – 0.50 maximum – – – 10.00 – 0.15 – 1.50 Minimum 0.9 0.01 – 0.40 Maximum 3.4 2.00 – 6.00 Species number 3.0 6.00 2 6.00 0.15 Density (individuals/m3 104) Copepoda Mean density (individuals/m3 104) Cladocera Mean density (individuals/m3 104) – 0.30 – Minimum 0.2 – – – Maximum 2.6 0.70 – 0.30 Species number 5.0 3.00 5 8.00 1.00 Rotatoria Mean density (individuals/m3 104) – 0.80 – Minimum 1.0 – – – Maximum 5.3 3.60 – 5.00 Species number Total species † 17.0 21.00 8 33.00 25.0 30.00 15 47.00 See de Bernardi et al. (1989); Manca et al. (1992); Commissione Internazionale per la Protezione delle Acque Italo-Svizzere (2001); Dalmiglio (unpubl. data). Italy’s Water Framework Directive 51 Como, Garda, Maggiore and Iseo is represented in Figs 3 and 4, respectively. All four lakes underwent an increase in total P concentrations during the 1960s and reached their highest values at the beginning of the 1980s, with the exception of Lake Garda, which showed minimal modifications in its environ- Table 8. mental conditions. In the following years, due to several technical (waste water treatment, load diversion) and administrative (P ban in detergent) measures adopted to prevent the onset of eutrophic phenomena, a significant decrease in P levels was registered. Since the beginning of the 1990s, a gradual decrease in P levels has been observed Fish communities’ composition in deep subalpine lakes† Species Como Garda Iseo Maggiore Alburnus alburnus alborella √ √ √ √ Alosa fallax lacustris √ √ √ √ Alosa fallax nilotica – – √ – Anguilla anguilla – √ √ √ Anguilla vulgaris √ – – – Barbus plebejus √ √ – √ Blennius fluviatilis – – – √ Carassius carassius – √ √ – Chondrostoma soetta √ – – √ Cyprinus carpio √ √ √ √ Coregonus morpha hybrida √ √ √ √ Coregonus phoxinus phoxinus – √ – – Coregonus sp. – √ – √ Coregonus macrophthalmus √ – – √ Cottus gobio √ √ √ √ Esox lucius √ √ √ √ – Ictalurus melas – √ – Lepomis gibbosus √ √ √ – Leuciscus cephalus √ √ √ √ Lota lota √ √ √ √ Lucioperca lucioperca – – – √ Micropterus salmoides – √ √ √ Onchorynchus mykiss √ – √ – Padogobius martensii √ – – √ Perca fluviatilis √ √ √ √ Phoxinus phoxinus √ √ – √ Rutilius erythrophthalmus √ √ √ – Rutilus rubilio – – – √ Rutilus pigus √ √ – √ Salmo gairdneri – √ – – Salmo trutta carpio – √ – – Salmo trutta fario – √ √ – Salmo trutta lacustris √ √ √ √ Salvelinus alpinus √ – √ – Salvelinus fontinalis – √ – √ Scardinius erythrophthalmus √ √ √ √ √ Telestessoufia muticellus √ – – Tinca tinca √ √ √ √ Total number 24 27 23 26 † See de Bernardi et al. (1989); Commissione Internazionale per la Protezione delle Acque Italo-Svizzere (2001); Dalmiglio (unpubl. data). 52 G. Premazzi et al. in Lake Maggiore; the present trophic state of the lake can be viewed as oligotrophic. Lake Iseo, however, shows two distinct trends in P concentrations: in the mixolimnion (0–80 m layer) these have decreased to the present value of about 25 µg/L, while below 100 m mean values register at approximately 80–85 µg/L (Premazzi et al. 1998). In all four lakes, mineral N concentrations have shown a general tendency to increase, followed in recent years by a less marked increase, or even stability. Nitrate concentration increase would be related to an increase in N loading from the lakes’ catchment basin, mainly due to atmospheric inputs rather than agricultural, domestic and industrial sources. Nitrate is the most important nitrogen compound in the subalpine lakes (up to 90–95% of the total). The low nitrate concentrations in lake Garda (relative to the concentrations in the other lakes) can be explained by a lesser impact of eutrophication on this lake. The slower water renewal time would result in a longer response time (higher resilience) of Lake Garda to an increased N load (Ambrosetti et al. 1992). In Table 6 the most recent data on chlorophyll a concentration for the subalpine lakes Como, Garda, Iseo Maggiore and Varese is shown. Phytoplankton There are no comparative studies for phytoplankton on the lakes Como, Garda, Iseo, Maggiore and Varese. However, the composition of the phytoplankton communities would register marked similarities from one lake to another, as regards density, biomass and species composition. A number of species are ubiquitous in these lakes. These are the blue-greens Oscillatoria rubescens, Coelosphaerium kuetzingianum and Microcystis sp., the diatoms Fragilaria crotonensis, Melosira islandica, Cyclotella sp. and Asterionella formosa, the coniugatophytes Mougeotia sp. and Closterium acutum, the cryptophytes Cryptomonas erosa, Rhodomonas lacustris and R. minuta, the chlorophyte Coelastrum sp. and the dinoflagellate Ceratium hirundinella (Ambrosetti et al. 1992; Manca et al. 1992; Commissione Internazionale per la Protezione delle Acque Italo-Svizzere 2001; Dalmiglio (unpubl. data); Premazzi 2002). It can be concluded that during the 1990s there was a general decrease in the P concentration in the deep Italian subalpine lakes. This, in its turn, has determined a decline of the phytoplankton biomass. Concurrently, there was an increase in the number of species with consequent generation of biodiversity of the phytoplankton communities, with substitution in the dominant species. However, no particular trend in biomass and chlorophyll a was evident, indicating a high resilience in the phytoplankton response to P loading reduction. However, the most important taxa of the phytoplankton communities are still represented by the bluegreens and the diatoms, even if replaced by new species. Table 6 summarizes the most recent data on phytoplankton density and biomass. Zooplankton The zooplankton found in the deep Italian subalpine lakes is typically represented by: Copepoda Eudiaptomus padanus, Cyclops abyssorum, Mixodiaptomus laciniatus and Mesocyclops leuckarti, Cladocera Diaphanosoma brachyurum, Daphnia hyalina, Eubosmina coregoni and Diaphanosoma brachiurum, and Rotatoria Keratella cochlearis and Kellicotia longispina (Dalmiglio (unpubl. data); Manca et al. 1992; Commissione Internazionale per la Protezione delle Acque Italo-Svizzere 2001). As regards studies on zooplankton, Lake Maggiore is the most studied environment since the last century. It was used as a test site for the discussion of theories and specific problems of a complex community such as that living in a large lake. Different aspects of the composition, evolution and dynamics of zooplankton are detailed in a comprehensive review (de Bernardi et al. 1989). This lake would be classified as a ‘copepods lake’, because this group represents the most stable component of the populations. Cladocerans are becoming progressively less abundant (from 10% to 2% in the last 10 years). These organisms would represent an indicator of the lake’s productivity. An important feature of the zooplankton in Lake Como is the rise in the density of cladocerans, due to Eubosmina coregoni and Diaphanosoma brachiurum, that at present represent a relevant portion of the zooplankton populations (Dalmiglio (unpubl. data); Chiaudani & Premazzi 1993). As concerns Lake Garda the marked dominance of copepods (22% of the total zooplankton population) in respect to cladocerans (2%) represents a positive signal for the trophic conditions. In fact, the increase in the density of cladocerans with an increase in the trophic level (eutrophication) is a well-consolidated fact for several water bodies (Manca et al. 1992). Because of a lack of data, it is not possible to delineate the evolution of the zooplankton populations in the lakes Iseo and Varese. Table 7 illustrates the most recent data on zooplankton in the lakes Como, Garda, Iseo and Maggiore. Fish There is scarcely any published data on fish communities for the subalpine Italian lakes. Therefore, information to individualize trends in the fish populations of these lakes in connection with their trophic evolutions, which occurred in past decades, is fragmentary and insufficient. Perhaps, the most detailed studies on fish are those existing for Lake Maggiore. Italy’s Water Framework Directive 53 change in respect to the 1980s when the catch of Alosa was the most important commercial catch. Three pelagic fish species (Alosa, Coregonus and Alborella) represent, on average, more than 60% of the total catches in the lake. This is a common characteristic of the deep subalpine lakes that have a reduced littoral zone and a prevailing pelagic area. However, for the other Italian subalpine lakes some general considerations can be made, based on qualitative observations (Dalmiglio (unpubl. data); Commissione Internazionale per la Protezione delle Acque Italo-Svizzere 2001). In Table 8 are listed the species recorded in the deep lakes Como, Garda, Iseo and Maggiore. The decrease in Lake Maggiore of the total fish catch, from 809 t/year in 1982 to 180 t/year in 1995, has been paralleled by marked changes of in-lake P concentration. From the data on fish population for Lake Como, two periods can be identified: the first from 1960 to the end of the 1970s, in which Cyprinids reached the highest values; the second (1980s) in which a progressive increase of Coregonus and Alosa was obser ved. Presently, these represent the major component of professional fishing. It is observed that the presence of Salmo trutta and Salvelinus alpinus is significantly decreased in recent years. Since the 1990s, Lake Garda has registered a marked increase in the catches of Coregonus. In fact, the catch for this fish was around 20 t/year in 1990 while six years later it reached values of 140 t/year. It represents a noticeable Table 9. DISCUSSION In order to achieve the established environmental quality objectives, considerable technical, administrative and economical efforts were made. In the last decade, several agreements among the Ministry of the Environment, the local authorities (Lombardy region and Varese province) and the European Commission were signed aiming to assess the environmental benefits of planned restoration programmes. Intensive research activities were carried out and projects developed (Chiaudani & Premazzi 1990; Chiaudani & Premazzi 1993; Premazzi et al. 1995; Premazzi et al. 1998). The reductions in P input to the lakes, due to the implementation of measures mentioned above, have in several Representative water quality parameters (mean values at the overturn) in the subalpine lakes Como, Garda, Iseo, Maggiore and Varese, for ex-ante (1980s) and ex-post (1999–2000) restoration periods† Parameters (µg/L) Como Garda Iseo Maggiore Varese Ex-ante 78.0 12.0 32.0 20.0 325.0 Ex-post 39.0 14.0 53.0 10.0 95.0 Ex-ante 60.0 5.0 18.0 15.0 258.0 Ex-post 30.0 6.0 51.0 7.0 63.0 Ex-ante 805.0 375.0 695.0 800.0 – Ex-post 878.0 383.0 773.0 820.0 – Ex-ante 790.0 353.0 675.0 795.0 230.0 Ex-post 858.0 391.0 754.0 810.0 377.0 Ex-ante 4.6 7.0 6.9 7.5 1.7 Ex-post 7.9 9.0 5.5 15.0 3.5 Ex-ante 6.9 3.9 6.2 5.0 35.0 Ex-post 4.1 3.0 7.1 2.9 12.0 Natural phosphorus level 7.5 8.4 9.1 6.9 18.5 Final goal 9.4 10.5 11.4 8.6 23.0 Intermediate goal 14.1 15.7 13.5 10.3 35.0 Current phosphorus level 35.0 14.0 50.0 9.0 95.0 Total phosphorus Reactive phosphorus Mineral nitrogen Nitrates Transparency Chlorophyll a † See Chiaudani & Premazzi (1993); Premazzi et al. (1998); Dalmiglio et al. (1999); Passino (1999); Commissione Internazionale per la Protezione delle Acque Italo-Svizzere (2001); Premazzi (2002). 54 G. Premazzi et al. cases reduced the in-lake P concentration and, in turn, resulted in favourable shifts in the phytoplankton communities and in the chlorophyll a concentrations in the majority of the subalpine lakes. Table 9 summarizes the lake water quality before and after restoration programmes in the lakes Como, Garda, Iseo, Maggiore and Varese. Figure 5 shows the present trophic level of these lakes with respect to the natural background P level and the established water quality objectives. In addition to the emission limit value approach, the regional authorities introduced the concept of receptive capacity of the water body in their Water Clean-up Plans. It gives the possibility of fixing stringent limits, according to the natural lake characteristics and to the characteristics of the contaminants (Piano Regionale Risanamento delle Acque 1992). This policy anticipated, in fact, the ‘combined approach’ of the EU (that is, the integration of quality objectives for water with emission standards for water contaminants), as indicated in the WFD. The Po River Authority has recently formulated directives intending to safeguard lake water quality by counteracting eutrophication of inland waters and taking into consideration the lakes’ uses. Objectives to be pursued and strategies to be adopted have also been defined (Autorità di Bacino del Fiume Po (unpubl. data-internal document, 1998); Autorità di Bacino del Fiume Po (unpubl. data-internal document, 2001)). The trophic level cannot, however, be ignored in the definition of quality objectives. Although not ignoring water quality criteria for different uses, a classification of qualitative characteristics of lakes, referring mainly to the trophic level, has been set up. The evaluation of present trophic levels, such as oligotrophy, mesotrophy and eutrophy, is necessary but not sufficient. Eutrophication is not necessarily the Fig. 5. Present conditions, water quality objectives and natural background concentration of subalpine lakes Como, Garda, Iseo, Maggiore and Varese, expressed as total phosphorus concentration. natural concentration; , intermediate goal; , , final goal; , current concentration (Dalmiglio et al. 1999). Table 10. Comparison of the external phosphorus loading and the in-lake phosphorus level, and of the managerial and the ecological objectives for the subalpine lakes Como, Garda, Iseo, Maggiore and Varese. The time required to attain the final goals of Water Clean-up Programmes (ecological objectives) is also indicated† Parameters Como Garda Iseo Maggiore Varese Phosphorus load (t/ year) 379.0 172.0 103.0 230–240 16 In-lake phosphorus level (µg/L) 35.0 15.0 24.0‡ 9–10 95 Present condition Managerial objective Compatible phosphorus load (t/ year) 250.0 120–125 72.0 220–240 13–14 In-lake phosphorus level (µg/L) 16.0 10.5–11.5 16–18 9–10 35–40 144.0 119.0 65.0 200–212 10–11 Ecological objective Phosphorus load (t/ year) In-lake phosphorus level (µg/L) Time required (year) 9.4 10.5 11.5 8 25–30 15–20 5–10 5–10 0 10–15 † See Chiaudani & Premazzi (1990); Premazzi et al. (1995); Premazzi et al. (1998); Regione Lombardia–Commissione Europea (1997). ‡ average value in the mixoliminion. The annual average value for the lake is 56 mg/m3. Italy’s Water Framework Directive consequence of anthropogenic activities. Many lakes can be naturally eutrophic due to their morphometric and geochemical characteristics of the catchment basin. Thus, the maximum objective achievable by restoration measures should not necessarily be oligotrophy, but to bring each lake to a level as close as possible to its presumptive natural status. Hence, realistic management plans should establish an ‘as close an approximation to a natural P state’ as the maximum achievable water quality objective (ecological objective) as possible, and an intermediate minimum water quality objective (managerial objective), to be intended as a P level in lake water which is acceptable for the social use of the water resource (Chiaudani & Premazzi 1988) Environmental quality objectives have been established after evaluating the natural P levels for each lacustrine environment in the Po river basin. The final ecological objectives were quantified as an increase of 20% in the natural P concentration for oligotrophic and oligo-mesotrophic waters, a 40% increase in the P level for mesotrophic and mesoeutrophic lakes and 50% for eutrophic lakes. Intermediate managerial objectives were identified as a 40% increase in the natural P concentration for oligo-mesotrophic lakes and an 80% increase in the P level for eutrophic waters (Passino et al. 1999). Table 10 compares the present situation of the subalpine lakes with the above objectives. The data from Dalmiglio et al. (1999) show a relative improvement in the condition of lakes Como and Varese, whereas Lake Iseo seems to have deteriorated in the last 10 years. The condition of Lake Garda is quite stable, indicating the high resilience of the largest Italian lake. In Lake Maggiore the ecological objectives have been achieved. The results of this research, coupling the combined approach to the environmental benefit assessment, should contribute to the improvement of water policy, making it more effective in restoring and safeguarding the lake environments. Case study: Lake Varese Lake Varese was first impacted by raw sewage (domestic and industrial) from Varese agglomeration early in the 1960s. Deteriorating water quality from algal blooms was reported in the press (Editor, 1963; Giuliani, 1997)and the scientific community addressed related issues (Vollenweider 1965). By 1965, public concern had resulted in initiatives to form a local agency (Consorzio Volontario di Tutela e Risanamento delle Acque) to address the problem of the lake’s management. The project, promoted by the action of the Varese province in 1967, included (i) a sewerage network (ii) an O-ring sewage diversion system, and (iii) a centralized wastewater treatment plant with phosphorus and nitrogen control. Waste waters received tertiary treatment in 1986 55 and diversion was completed in 1994 (de Fraja Frangipane (unpubl. data-internal document, 1977); Premazzi (unpubl. data-internal document, 1994)). By the 1990s, Lake Varese was the subject of a cooperative research programme among the European Commission, the Italian Ministry of the Environment, the Lombardy region and the Varese province (Premazzi et al. 1995). The goals of these studies were to evaluate the trophic status and its temporal evolution and to assess the environmental benefits of restoration programmes carried out in relation to the established water quality objectives. The water quality objective established by the Regional Clean-up Act (Piano Regionale di Risanamento delle Acque 1992) is to achieve a P concentration as close as possible to the natural background P level with an intermediate objective of 40 µg/L and a final objective of 30 µg/L. The lake responded in a relatively rapid way to decreased nutrient loadings, as scientists had predicted. A marked reduction of the external P loads was observed, from 50 t/year in the prediversion period in 1986 to 25 t/year in 1990, and to 11 t/year in 1997, as a result of the completion of the depurative measures. The residual P load represents no more than 18% of the total P load generated in the catchment basin: 75% is of diffuse origin. By 1999, noticeable differences occurred. Total P decreased from 290 µg/L to 120 µg/l, Secchi disc transparency increased from 1.8 m to 3.2 m and epilimnetic chlorophyll decreased from 27 µg/L to 12 µg/L. Nitrogen was no longer limiting after restoration efforts. It had become a limiting nutrient because of the large biomass of algae produced by increased P loads. Nuisance blooms of algae were no longer a threat to the lake as in the previous periods (Premazzi 2002). However, mathematical models predicted quite a long time (25–30 years) to attain the best P concentration at the equilibrium (40–45 µg/L), even higher than that considered to be the final restoration objective for the lake. These models recognized the importance of internal P loading in maintaining biological productivity of the lake (Rossi & Premazzi 1991). Diversion of cultural nutrient loading, although essential, may not be sufficient to return the lake, suffering significant internal loads, to its undisturbed condition. Curtailment of internal loading may be also required. Lake scientists predicted that the application of the in-lake measure such as hypolimnetic withdrawal would accelerate lake recovery by controlling P release from anoxic sediments (Premazzi 1994). By the summer of 2000, siphoning the nutrient-rich deep waters from the lake was effective because scientists convinced the authorities and the public that Lake Varese would 56 G. Premazzi et al. become better in a shorter time than predicted from loading models. In fact, scenarios for improving the lake water quality would suggest a reduction of the total P concentration in the lake water up to approximately 25–30 µg/L after a few water overturns (10–15 years). This calculated equilibrium concentration is to be considered the closest value, realistically attainable, to the natural background level (20 µg/L). Preliminary results are greatly encouraging: it appears that the greater the amount of phosphorus discharged in this way, the greater is the decline in P concentration in the upper water layers where algae grow (Premazzi, unpubl. data). FINAL CONCLUSIONS Ideally, the knowledge about the water status of lakes would derive from monitoring and classification as set out in legislation, of which the Italian decrees are a good example, and even from more comprehensive information as required in the WFD. The WFD obliges member states to provide information on the status of their lakes and to assess long-term changes brought about by natural and anthropogenic activities through a number of monitoring obligations (surveillance monitoring). The Directive also requires member states to set quality objectives for both Table 11. natural and artificial lakes. The status of lakes is assessed through the observation of a number of elements that include biological elements, hydro-morphological parameters and the physicochemical condition of the water (Table 11). In order to assess whether a lake falls within the appropriate category of ‘water status’, member states will have to carry out sufficient monitoring of all these characteristics as a minimum requirement. The acquired data is then used to place the water body in one of the three quality classes, high, good, or moderate, as defined in Annex V of the WFD (European Communities 2000). ‘Good status’ is generally described as a situation where the values of the biological elements for a lake type show evidence of the impact of human activity but deviate only slightly from those normally associated with the lake type under undisturbed conditions. Thus, the results of the monitoring systems will be expressed as the ratio between the observed biological parameters in a lake and the expected numerical value for the pristine reference condition for that type of lake (ecological quality ratio, EQR). Conscious of the lack of experience in the use of many biological elements for classification purposes as specified in Annex V of the WFD, the European Commission Quality elements to be considered in determining the water status for lakes† Biological Hydro-morphological Chemical and physicochemical Phytoplankton Water flow regime Transparency Other aquatic flora Connection with aquifers Thermal conditions Benthic invertebrates Residence time Oxygen levels Fish Lake shore Salinity Lake depth Acidification status Lake bed conditions Nutrients Specific pollutants † See European Communities (2000). Table 12. Examples of diverse compatibility by the European Union member states with the Water Framework Directive requirements for monitoring nutrients Member state Monitoring of nutrients Classification based on reference conditions All lakes included Belgium No – – Finland Yes No Yes Greece No – – Italy Yes Yes >0.5 km2 UK (Scotland) Yes Yes >1 km2 Sweden Yes Yes Yes Data elaborated by the Institute for Environment and Sustainability, Joint Research Centre, Ispra, from the questionnaire of Working Group 2.3, Reference Conditions, in European Commission (2002). Italy’s Water Framework Directive (Directorate, General Environment) set up in 2001 a working group on intercalibration (led by the Joint Research Centre, Ispra). It aims at obtaining common understanding of ecological status of the surface waters all over the EU and at ensuring comparability of the EQR scales (that is, good ecological quality should have the same ecological meaning throughout the EU). Establishing comparable class boundaries for four categories of natural waters is crucial in order to have an equal level of ambition in achieving ‘good status’ of the surface waters in different member states. The intercalibration exercise, developed within the Common Implementation Strategy of the WFD, should be completed by June 2006 and results published by December 2006. However, the reality between the member states’ knowledge of their lakes’ quality status and the national monitoring and classification systems is very different. The above overview for the Italian subalpine lakes, resulting from a collation of information from several sources, including the national monitoring programmes, gives us an idea of the shortage of data, especially for biological elements, in comparison to the requirements of the WFD. These lakes are amongst the most surveyed in Italy, but despite that, we would conclude that the current monitoring and classification system does not comply, on the whole, with the WFD. Yet, the situation in the rest of the EU is no better than in Italy. Preliminary results from a questionnaire by the REFCOND Project (European Commission 2002) show that, even for the simplest quality elements (nutrients), there are only three member states for which monitoring of these in existing national classification systems is compatible with the WFD requirements (Table 12). The table shows that Italy and Sweden are two of the complying member states regarding the monitoring of nutrient concentrations in lakes with more than 0.5 km2 surface area and the classification of these considering its deviation from reference (natural) nutrient values (National Board of Waters and the Environment 1988; Wiederholm 1989; Swedish Environmental Protection Agency 1991; Andersen et al. 1997; Brunel et al., unpubl.data-internal report, 1997; Vouristo 1998; Passino et al. 1999; Agence de l’eau 2000a; Agence de l’eau 2000b). The Scottish approach to lake classification identifies four classes of water quality and establishes standards for each of the classes. The water quality change associated with nutrient enrichment is determined by the ratio of current and hindcasted total P concentration. Finland partially complies with the WFD because it monitors nutrients on the basis of water uses, but does not classify by comparing with reference conditions. 57 Belgium indicates that nutrients are not in the country’s national monitoring programmes. Greece reports that the national research infrastructure is currently inadequate to meet the principal obligations that the WFD places on the country. Most of the existing experience of lake management refers to the problem of eutrophication, as recently reviewed by Cardoso et al. (2001). There are numerous data sets available for specific lakes as a result of long-term studies carried out by research organizations and universities to assess trend evolution in the trophic state of lakes. In practice, the data as required by the WFD is scarce and the application of the new concept of ‘ecological status’ is a largely unknown issue. This is a new concept to water quality/quantity management and arises from consideration that natural environmental conditions vary throughout the EU. This must be taken into account in any water’s planning project. Management plans for lakes need to be refocused because these surface bodies are often seen as a quite separate issue in river basin management. The WFD changes this attitude in that lakes must be considered as ecological entities to be accounted for in any river basin plans. The need to reformulate the national monitoring networks (and the classification systems) to include all the elements that the WFD oblige member states to monitor, looks set to be a must for all EU countries. On the other hand, there is not much time left to do it: surveys should be completed by 2004 and in 2006 the monitoring programmes should start. Before these dates, member states will have to design their monitoring programmes and enact monitoring network(s) able to carry out the sampling of all the elements in the WFD with the appropriate density and frequency. These are major tasks for such a short time available, and hopefully, there will be progress from the current situation, where the requirements of the WFD are still an ideal, to reality in due time. REFERENCES Agence de l’eau (2000a) Systeme d’evaluation de la qualitê biologique des cours d’eau. Principês generaux. Les Etudes des Agences de l’Eau. Version 0. No. 7. Agence de l’eau (2000b) Systeme d’evaluation de la qualitê biologique des cours d’eau. Principês generaux. Les Etudes des Agences de l’Eau. Version O. No. 72. Ambrosetti W., Barbanti L., Mosello R. & Pugnetti A. (1992) Limnological studies on the deep southern alpine lakes Maggiore, Lugano, Como, Iseo and Garda. Mem. Ist. Ital. Idrobiol. 50, 117–46. Andersen B. et al. (1997) SFT Veiledning. No. 1468. 58 de Bernardi R., Manca M. & Giussani G. (1989) Zooplankton in Lake Maggiore: an overview. Mem. Ist. Ital. Idrobiol. 46, 103–23. Cardoso A. C., Duchemin J., Magoarou P. & Premazzi G. (2001) Criteria for the identification of freshwaters subject to eutrophication. Office For Official Publications of the European Communities, Luxembourg; European Union Report 19810. Chiaudani G. & Premazzi G. (1988) Appraisal of the possible methods of combating the threat of eutrophication in Community waters. Ing. Amb. 7. Chiaudani G. & Premazzi G. (1990) Il lago di Garda: Evoluzione trofica e condizioni attuali. Office For Official Publications of the European Communities, Luxembourg; European Union Report 12925. Chiaudani G. & Premazzi G. (1993) Il lago di Como: Condizioni ambientali attuali e modello di previsione dell’evoluzione della qualità delle acque. Office For Official Publications of the European Communities, Luxembourg; European Union Report 15267. Chiaudani G., Premazzi G. & Rossi G. (1986) Problemi e metodi nei piani di risanamento di tutela e gestione delle risorse dei grandi bacini lacustri: il caso del lago di Como. Ing. Amb. 9, 503–10. Commissione Internazionale per la Protezione delle Acque Italo-Svizzere (eds). (2001) Ricerche sull’evoluzione del Lago Maggiore, Campagna 1999. Regione Lombardia, Milan. Consiglio Nazionale delle Ricerche Istituto di Ricerca sulle Acque (1984) Castato dei laghi Italiani. Volume 1-Italia settentrionale, parte prima. Consiglio Nazionale delle Ricerche Istituto di Ricerca sulle Acque,Rome; No. 72. Dalmiglio A. et al. (1999) The scientific and administrative approach to lake management in Lombardy region (Northern Italy). In: Lake 99 Sustainable Lake Management. (ed S. E. Jorgensen) pp. S14A–3. Proceedings of the 8th International Conference on the Conservation and Management of Lakes, Vol. II, May 17–21, 1999. DIS Congress Ser vice Copenhagen, Copenhagen. Decreto Legislativo (1999) Disposizioni sulla tutela delle acque dall’inquinamento e recepimento della direttiva 91/271/EEC concernente il trattamento delle acque reflue urbane e della direttiva 91/676/EEC relativa alla protezione delle acque dall’inquinamento provocato dai nitrati provenienti da fonti agricole, DL No. 152, No. 124. Decreto Legislativo (2000) Disposizioni correttive e integrative del decreto legislativo, No. 152 (11 Maggio 1999) in materia di tutela delle acque dall’inquinamento, a norma dell’articolo 1,comma 4, legge No. 128 (24 Aprile 1998), DL No. 258, No. 218. G. Premazzi et al. Editor (1963) Salvare il lago di Varese. La Prealpina 1 July. European Commission (1996) European Community environment legislation. Volume 1-General policy. Office for Official Publications of the European Communities, Luxembourg. European Commission (2002) Common implementation strategy for the Water Framework Directive. Working group 2.3. Guidance on establishing reference conditions and ecological status class boundaries for inland surface waters. Draft Report. European Communities (1976) Directive 76/464/EEC on pollution caused by certain dangerous substances discharged into the aquatic environment of the Community. Official Journal of the European Communities. L129. European Communities (1979a) Directive 79/869/EEC concerning the methods and frequencies of sampling and analysis of surface water intended for the abstraction of drinking water in the Member States. Official Journal of the European Communities. L 271. European Communities (1979b) Directive 79/923/EEC on the quality required of shellfish waters. Official Journal of the European Communities. L 281. European Communities (1997) Treaty on European Union. Official Journal of the European Communities. C 340. European Communities (2000) Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy. Official Journal of the European Communities. L 327. Giuliani G. (1997) Lago di Varese, ecco i soldi. La Prealpina 30 July. Manca M., Calderoni A. & Mosello R. (1992) Limnological research in Lake Maggiore: studies on hydrochemistry and plankton. Mem. Ist. Ital. Idrobiol. 50, 171–200. Ministry of the Environment (ed). (1997) Relazione sullo stato dell’ambiente. Istituto Poligrafico e Zecca dello Stato, Rome. Mosello R., Calderoni A. & de Bernardi R. (1997) [Research on the evolution of the deep southern alpine lakes performed by the CNR–Istituto Italiano di Idrobiologia.] Documenta Ist. Ital. Idrobiol. 61, 19–32. (In Italian.) National Board of Waters and the Environment (1988) Classification of the usability of watercourses based on water quality. Publications of Water and Environment Administration. Helsinki. Passino R., Chiaudani G., Giovanardi F. & Premazzi G. (1999) Management of great subalpine Italian lakes by the Po River Authority. In: (ed. S. E. Jorgensen) pp. S7A–9. Proceedings of the 8th International Conference on the Conservation and Management of Lakes, Vol. I, May Italy’s Water Framework Directive 17–21, 1999. DIS Congress Ser vice Copenhagen, Copenhagen. Piano Regionale di Risanamento delle Acque (1992) Piano Regionale di Risanamento delle Acque: Criteri di pianificazione in rapporto alla gestione delle risorse idriche lombarde. Regione Lombardia, Milan. Piontelli R. & Tonolli V. (1964) Il tempo di residenza delle acque lacustri in relazione ai fenomeni di arricchimento in sostanze immesse, con particolare riguardo al lago Maggiore. Mem. Ist. Ital. Idrobiol. 17, 247–66. Premazzi G. (2002) Lago di Varese: Primo biennio di attività degli interventi diretti (2000/2001). Relazione presentata al convegno Il risanamento del lago di Varese: questi i risultati. Università dell’Insubria, Varese. Premazzi G., Cardoso A. C., Rodari E. et al. (1998) Il lago d’Iseo: Condizioni ambientali e prospettive di risanamento. Office For Official Publications of the European Communities, Luxembourg; European Union Report 17720. Premazzi G., Chiaudani G., Pereira A., Rodari E. & Rossi G. (1995) Lago di Varese: condizioni ambientali e soluzioni per il risanamento.Office For Official Publications of the European Communities, Luxembourg; European Union Report 16233. Regione Lombardia–Commissione Europea (1997) Studi finalizzati alla definizione degli strumenti per l’ottimizzazione delle procedure di pianificazione, gestione e tutela delle risorse idriche. Convenzione Rapporto Finale. CCR-Ispra, Direzione Generale, Ispra; No. 12635–97–02. 2001. 59 Repubblica Italiana (1989) Norme per il riassetto organizzativo e funzionale della difesa del suolo. No. 183. Repubblica Italiana (1994a) Disposizioni in material di risorse idriche. No. 36. Repubblica Italiana (1994b) Conversione in legge, con modificazione, del decreto-legge numero 496 (4 Dicembre 1993), recante disposizioni urgenti sulla riorganizzazione dei controlli ambientali e istituzione dell’Agenzia Nazionale per la Protezione dell’Ambiente. No. 61. Rossi G. (1991) Modelling lake pollution. Office For Official Publications of the European Communities, Luxembourg; European Union Report 13998. Rossi G. & Premazzi G. (1975) On the calculation of the mean residence time in monomictic lakes. Idrol. Sci. Bull. 20, 575–88. Rossi G. & Premazzi G. (1991) Delay in lake recovery caused by internal loading. Water Research 25, 567–75. Swedish Environmental Protection Agency (1991) Quality Criteria for Lakes and Watercourses. Naturvårdsverket. Vollenweider R. A. (1965) Materiali ed idee per una idrochimica delle acque insubriche. Mem. Ist. Ital. Idrobiol. 19, 213–86. Vouristo H. (1998) Water quality classification of Finnish inland waters. Eur. Water Manage. 1, 35–40. Wiederholm T. (1989) Assessment Criteria for Lakes and Watercourses. Background document No. 1. SVN Report No. 3627.