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 1Institute for Environment and Sustainability, European Commission, Joint Research Centre, 21020, Ispra, Italy, 2Agenzia 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 con- cerns (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 2. Legislative decree number 258/00 (Decreto Legislativo QUALITY PROTECTION IN ITALY 2000), which concerns the protection of water from In Italy the regions are charged with water monitoring pollution and integrates thoroughly some topics of the activities and the central government is empowered with legislative decree 152/99 (Decreto Legislativo 1999). For supervision, coordination and regulation tasks. The basic the first time in Italy, the two decrees set environmental legal framework for water quality protection and monitoring and functional objectives for water bodies. is established by: 3. Law 183/89 (Repubblica Italiana 1989) which establishes 1. Legislative decree number 152/99, which transposes river basins as the unit where environmental protection the European Union (EU) Directives 91/271/EEC and activities have to be designed and performed, and creates 91/676/EEC, and defines the main requirements for river basin authorities. water quality monitoring in inland waters, coastal waters, 4. Law 36/94 (Repubblica Italiana 1994a) which concerns estuaries and lagoons (Decreto Legislativo 1999). the reorganization of the public services that are charged with water abstraction, water supply and distribution, and waste water treatment. *Corresponding author. Email: [email protected] 5. Law 61/94(Repubblica Italiana 1994b) which relates to Accepted for publication 29 November 2002. the reorganization of environmental controls and the 42 G. Premazzi et al.
Table1. Classification of the lakes’ ecological status†
Parameters CLASS 1 CLASS 2 CLASS 3 CLASS 4 CLASS 5 (high) (good) (moderate) (poor) (bad)
Transparency (m) >5 5 2 1.5 1 Hypolimnetic oxygen (% saturation) >80 80 60 40.0 20 Chlorophyll (µg/L) <3 6 >10 25.0 >25 Total phosphorus (µg/L) <10 25 50 100.0 >100
†See Decreto Legislativo (1999).
Table2. The main chemical compounds monitored in surface characterization, discharge (point and diffuse) impact assess- inland waters† ment and post-pollution incidents. Both of the decrees anticipated the principles of Inorganic Organic the EU Water Framework Directive (WFD) (European cadmium aldrin Communities 2000) and have substantially modified the total chromium dieldrin legislation in the field of water in Italy. Important changes mercury endrin were introduced, both in the monitoring systems and in the nickel isodrin classification methods for surface waters. The environmental lead DDT‡ quality status will be determined not only by monitoring the copper hexachlorobenzene aqueous matrix, but also the sediment and the biota, the zinc hexachlorocyclohexane latter intended both as accumulator of harmful substances hexachlorobutadiene and recorder/integrator of environmental pressures. trichlorobenzene The new monitoring system consists of two steps: a chloroform cognitive phase and a full operational phase. In the first perchloroethylene phase (two-year duration), general information should be pentachlorophenol gathered regarding surface water bodies, in order to be tetrachloromethane acquainted with the lake and its environmental conditions trichloroethylene (for example, pressures from the catchment). This evalu- 1,2 dichloroethane ation will permit the establishment of a monitoring plan, and thus, the definition of the minimum number of sampling †See Decreto Legislativo (1999); ‡DDT, 1, 1, 1 trichloro-2, 2 bis points (depending on the lake size), the identification of (4-chlorophenyl) ethane. the criteria for selection of the sampling location and the sampling frequency. National Agency for Environmental Protection and All lakes with a surface area 0.5 km2 should be monit- Regional Agencies ored. For lakes with a surface area <80 km2, the sampling A reorganization of the administrative system for river point coincides with that of the maximum depth of the water management has recently taken place in Italy, partly as a body. However, by default, in the absence of bathymetric result of recognition of the growing importance of taking an maps, it could be located at the centre of the lake. For lakes integrated approach to environmental management. River with a surface area >80 km2 or of irregular configuration (for basin authorities have been set up covering six basins of example, forming bays or arms), the sampling points are national importance (the largest and most important one is fixed on a case-by-case basis. In each of the fixed sampling that of the Po River), as well as 15 regional and 17 inter- stations, chosen with respect to the desired information and regional basins. in conformity to local conditions, at least three sampling The responsibility for environmental protection and depths should be considered: 1 m from the lake surface, 1 m monitoring has been largely devolved from the national above the lake bottom and a depth in the middle of the level to the regions, provided that the minimum require- water column. For shallow lakes (z max 5 m) the number ments of the national legislation are satisfied. The design of of samples within the water column are reduced to two monitoring programmes is undertaken at the local level, on (surface and bottom). For lakes deserving particular pro- a case-by-case basis. The range and extent of programmes tection and safeguarding, the sampling profile should be may vary but local monitoring can be divided into different much more detailed. As an example, the monitoring pro- categories, such as trend detection and general quality gramme undertaken in the deepest Italian lake, Como, Italy’s Water Framework Directive 43 intended as a strategic water body for the abstraction of water body shall be determined by its ecological and chem- drinking water and of particular environmental value, ical status, and classified accordingly to the five classes set includes six different stations for a total of 62 sampling out in Table 3. depths; only the water column at the maximum depth (410 m) is described by 12 sampling depths. BASIC FEATURES OF THE WATER The operational phase indicates that monitoring FRAMEWORK DIRECTIVE programmes could take place at a reduced frequency and The new WFD is the major piece of EU legislation with at a limited number of sampling stations for only basic environment at its core and it will guide efforts for attaining (mandatory) quality elements, if the surface water bodies a sustainable aquatic environment in the years to come. The concerned reach good/high status and there is no evidence WFD is based on a ‘framework philosophy’ in line with the that the impacts on the water bodies have changed. principle of subsidiarity. It sets only the objectives to be As concerns the classification of the lake quality status, fulfilled by member states (for example, good water the allocation of a lake to a certain environmental class will quality), and defines the organizational structure (river be done by referring to the ecological and chemical status. basin authorities) and mechanisms (existing legislation A series of relevant quality elements are used for the and further measures) to achieve them. As such, the WFD definition of the ecological status of lakes: these are mainly best exemplifies the new approach in the EU environmental ascribable to eutrophication. They include the following policy, where environmental protection is married with sub- physicochemical and chemical elements: sidiarity through the division of objectives at a European • Transparency (minimum annual value) level and standards/measures at a national level. • Hypolimnetic oxygen saturation (minimum annual value The WFD will also replace many of the ‘first waves’ legis- during stratification) lation such as the directive on surface water for drinking • Chlorophyll a (maximum annual value) waters abstraction (European Communities 1979a) and the • Total phosphorus (P), (maximum annual value) fish and shellfish water directives (European Communities The classification of the ecological status shall be repre- 1979b). This satisfies the call for deregulation (simplifi- sented by the worst of the values from the monitoring results cation) of the existing legislative framework. On the other of the quality elements. The assignment to the appropriate end, the European Commission considered that the public water status will be done using the following class bound- health standards (such as those of the drinking and bathing ary numerical scale (Table 1). directives) should not be affected (European Commission The chemical status is defined as that exceeding (or not) 1996). the threshold limits for some micropollutants and hazardous In the WFD one can see elements from all the different substances, defined on a catchment basis for a reference forces that guided the reform of EU water policy, that is, water body. The list of the main chemical compounds to be environmental protection, deregulation and subsidiarity. monitored in surface inland waters is shown in Table 2. Moreover, elements of the economic instruments approach The limit values and quality objectives established under (introduction of the cost recovery principle), quantitative the five daughters directives of Directive 76/464/EEC- concerns (setting of minimum flow objectives for rivers and dangerous substances (European Communities 1976)-will abstraction limits for ground waters) and the quest for consider emission limit values and environmental quality integration (river basin management with representation of standards, respectively, in the evaluation of the chemical all stakeholders) are all reflected in the WFD. status for lakes. Arithmetic mean values are considered for A number of new strategies will result from the imple- the classification. mentation of the WFD. Specific issues that are important in Therefore, the environmental status of a surface inland formulating a sectorial strategy include the following:
Table3. Classification of the environmental status of surface inland water bodies†
Ecological status CLASS 1 CLASS 2 CLASS 3 CLASS 4 CLASS 5 Micro-pollutants and hazardous substances concentrations, as per Table 2
Threshold value HIGH GOOD MODERATE POOR BAD > Threshold value POOR POOR POOR POOR BAD
†See Decreto Legislativo (1999) 44 G. Premazzi et al.
Table4. 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 1km2 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 Basically, two different approaches to tackle water pollution to be managed on the basis of river basins, rather than exist at European (member state) level: according to geographical or political boundaries. This • limiting pollution at the source by setting emission limit enables assessment of all activities which may affect the values (ELV) or other emission controls watercourse, and their eventual control by measures which • establishing water quality objectives (WQO) for water may be specific to the conditions of the river basin. The WFD bodies requires river basin management plans to be drawn up on The WFD is based on a combined approach where ELVs a river basin basis. It may be necessary to subdivide a large and WQOs are used to mutually reinforce each other. In river basin into smaller units, and sometimes a particular any particular situation, the more rigorous approach will water type may justify its own plan. apply. This combined approach is also in accordance with principles established in the treaty (European Communities Programme of measures 1997). For example, the precautionary principle, which Central to each river basin management plan is a programme suggests that environmental damage should, as a priority, of measures to ensure that all waters in the river basin be rectified at the source and that environmental conditions achieve good water status. The starting point for this pro- in the various regions shall be taken into consideration. gramme is the full implementation of any relevant national or local legislation as well as of a range of EU legislation on Monitoring programme water and related issues. If this basic set of measures is not Monitoring is an essential part of the implementation of enough to ensure that the goal of good water status is the WFD. Such systematic monitoring of surface water reached, the programme must be supplemented with what- and groundwater quality and quantity can be categorized ever further measures are necessary. These might include as: stricter controls on polluting emissions from industry or 1. Surveillance monitoring, which is undertaken to provide agriculture and urban waste water sources In this context, information on the status of water, to identify its initial con- land use planning might be a key issue to be taken into dition and to assess long-term changes, both from natural account. and anthropogenic activities, in the catchment basin.
Table4. (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 47
2. Operational monitoring, which is undertaken to assess The comparison of the provisions, considered by the legis- the success, or otherwise, of measures enacted to lative decrees and the WFD, for the determination of the improve the situation. ecological status of lakes, is reported in Table 4. 3. Investigative monitoring, which is undertaken in problem areas where an accidental pollution has occurred or THE PRESENT CONDITION OF THE MOST where the causes of a problem in meeting environmental IMPORTANT LAKES IN THE ITALIAN objectives is not known. LAKE DISTRICT Data on monitoring is publicly available, and also forms In Italy there are more than 2000 lakes. Of these, 389 are the basis for regular reporting to the European Commission, freshwater (natural, enlarged natural and reservoirs) and 104 as well as contributing to the monitoring network within the are coastal with brackish water, excluding lagoons. One European Environment Agency. hundred and forty seven of these aquatic environments (87 lakes and 60 reservoirs) have been classified according Cost recovery to Organization for Economic Cooperation and Development The application of economic instruments such as charges criteria. P is the main substance responsible for the eutrophi- for use of water as a resource or for the discharge of cation process because it was identified as the limiting effluents into watercourses is a policy explicitly endorsed factor in 85% of examined lakes. Only 19% of lakes and reser- in the new directive. The ‘polluter pays’ principle must be voirs are in oligotrophic conditions, 40% are classified as applied, and economic assessment becomes an essential part mesotrophic and 41% as eutrophic. Among these, 10% are of water management planning. The principle of charges for considered to be hypertrophic (Ministry of the Environment water reflecting true costs is a radical innovation at European 1997). level. There is a danger in this proposal that water may The most important Italian lake district is located in become too expensive a commodity for many, and a general northern Italy and includes the deep subalpine lakes and reduction in its beneficial use may result. some small-medium insubrian lakes (Fig. 1). Together these represent more than 80% of the total Italian lacustrine Public consultation volume. The WFD requires consultation to take place and the rele- Hereinafter, it is intended to summarize the state-of-the- vant authorities should arrange consultation mechanisms art knowledge of the selected Italian subalpine lakes Como, with the interested parties such as the general public, Garda, Iseo, Maggiore and Varese. In particular, focus has non-government organizations, farmers and water com- been placed on those parameters directly linked to the lake panies. In this context, consultation with all relevant trophy (nutrients) and on some biological elements (phyto- parties might achieve a best cost-effectiveness and identify plankton, zooplankton and fish) in view of the implemen- the best combination of measures on a proportionate tation of Decreto Legislativo number 258/00 (Decreto level. Therefore, preparation of those parts of the WFD Legislativo 2000) and the WFD. The case study of Lake addressing information and consultation of all stakeholder Varese is highlighted because it represents a case of lake groups and the public, should be subject to serious management which is unique in Italy, in which lake restor- efforts. ation technology is applied to accelerate the return to Integration of stakeholders and the civil society in deci- earlier (more natural) conditions, after being impacted by sion making, by promoting transparency and information eutrophication. to the public and by offering a unique opportunity for involving stakeholders in the development of river basin General characteristics management plans, is a central concept of the WFD. 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 Fig. 1. Map of the Italian lake district (Passino et al. 1999). Area, Istituto di Ricerca sulle Acque (1984), Lake Como (or Lario) 71 057 km2; Regions, Piemonte, Valle d’Aosta, Lombardia, is the deepest Italian lake and the third in terms of surface Veneto, Liguria, Emilia-Romagna, Provincia Autonoma di Trento; area and volume, after lakes Garda (or Benaco) and Population, 16 000 000; head of cattle, 4 188 000; head of Maggiore (or Verbano). Its drainage basin occupies an area 2 2 pigs, 5 232 000; maximum population density (Lambro area), of 4552 km , of which 487 km is in the Swiss territory. The 1478 inhabitants (ab)/km2; minimum population density (Trebbia particular shape of the lake forms three distinct sub-basins: valley), 25 (ab)/km2; groundwater abstractions, 5.3 109 m3/year; the western basin (Como), the eastern basin (Lecco) and surface water abstractions, 25.1 109 m3/year. an upper basin. 48 G. Premazzi et al.
Lake Garda (Benaco) is the largest Italian lake with a Lake Varese is a relatively small Insubrian lake, belong- surface area of 368 km2 and it is located 65 m a. s. l. (lower ing to the catchment area of Lake, Maggiore. It has had a altitude by comparing with the other Italian subalpine long history (since the 1960s) of water quality deterioration lakes). Lake to drainage area ratio is about 1/6, lower in as the result of cultural eutrophication. Its catchment basin respect to that of other lakes (≈ 1/30). Two sub-basins can is one of the most densely populated areas in Italy (up to be distinguished. 700 inhabitants/km2) and is associated with many industrial Lake Iseo (or Sebino) is the fourth Italian lake with a and commercial activities. It is the first example in Italy of surface area of 60.9 km2. A specific feature is that it the use of in-lake methods to counteract the problems includes the largest European lacustrine island (area, caused by excessive nutrient enrichment. 4km2; height, 414 m). The rainfall regime has the typical behaviour of alpine Lake Maggiore (Verbano) is the second Italian lake in areas, with concentration of precipitation between May and terms of surface area and volume. Its drainage basin November. Approximately 70–75% of the mean annual occupies an area of 6600 km2, of which 50% is in the precipitation volume (1200 mm/year for Lake Garda, Swiss territory. Yet 80% of the lake surface is in Italian 1800 mm/year for Lake Maggiore) is concentrated in territory. this period.
Table5. Main morphometric and hydrological characteristics of the subalpine lakes Como, Garda, Iseo, Maggiore and Varese†
Parameters Como Garda Iseo Maggiore Varese
Latitude N 46 10 45 40 45 44 45 47 45 48 Longitude E (G)‡ 09 16 10 41 10 04 8 40 8 45 Drainage area (km2) 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 – – – Lake volume (106 m3) (e. basin)¶: 3702 3264 – – – Lake volume (106 m3) (u. basin)††: 10236–––– Theoretical renewal time (year) 4.5 26.6 4.1 4 1.90 Effective renewal time (year) (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 Maximum depth (m) 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)
†See Rossi & Premazzi (1975); Rossi & Premazzi (1991); ‡G, Greenwich. §w, western; ¶e, eastern; ††u, upper.
Fig. 2. The evolution of the average dissolved oxygen concen- tration 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 49
Lake water characteristics: 1999) have occurred. In Lake Iseo since 1981, no full circu- temperature and oxygen lation occurred and the volume affected by mixing is less Two hydrodynamic characteristics are of most importance than 50% of the total lake volume. The deepest basin of in the deep subalpine lakes, the water renewal time and this lake would be considered at risk of meromixis, and the vertical mixing. The effective mean residence time was consequently, noticeable chemical differences exist between evaluated in all subalpine lakes because this parameter is the upper 80 m of the water column (mixolimnion) and included in eutrophication models and its consideration is the deepest layers. Thus, two different values should be indispensable in lake restoration. For Lake Maggiore, the necessary to describe the chemical conditions of the lake mean water renewal time has been estimated to be 14.5 years (Premazzi et al. 1998). by Piontelli and Tonolli (1964). Other lake renewal times The evolution of the average dissolved oxygen concen- were estimated by Rossi and Premazzi (1975), Chiaudani tration in the hypolimnetic waters of the lakes Como, Garda, et al. (1986), Rossi and Premazzi (1991) and Rossi (1991), Maggiore and Iseo is represented in Fig. 2. Dissolved as reported in Table 5. The second important hydrodynamic oxygen is roughly present between 6 mg and 9 mg O2/L. feature of these great lakes is their specific holo-oligomixis. Despite the partial overturn of the waters, anoxic conditions An analysis of the thermal profiles suggests that these were never observed in the bottom layers where oxygen water bodies can be considered as oligomictic basins saturation values fluctuated from 20% to 60%. The exceptions with a winter circulation (January–March) and summer are Lake Iseo, where in the deepest basin (below 200 m) stratification (June–October). However, a complete anoxic conditions were registered, and Lake Varese, where homogenization of the waters is only found in the from June to October anoxic conditions are measured in shallower basins with average temperatures ranging about 60% of the lake volume. In the epilimnion of all from 5.5°C to 6.8°C. The lake volume affected by mixing these lakes, typical conditions of over-saturation (110–140%) varies from 40% to about 70% of the total volume. The are observed during the summer months, when primary complete overturn can only occur in conjunction with production is the highest. The oxygenation conditions of particularly cold and windy winters. The mixing depths in the lakes Iseo and Varese would be considered unsatis- these lakes ranged from a minimum of 50 m to a maximum factory and typical of highly productive, eutrophicated of 250 m. For example, in Lake Maggiore in the past environments (Ambrosetti et al. 1992; Mosello et al. 1997; 50 years, only four complete overturns (1956, 1963, 1970, Premazzi et al. 1998; Premazzi 2002).
Fig. 3. The evolution of the average total phosphorus concen- tration 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 circu- lation 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. 50 G. Premazzi et al.
Nutrients and chlorophyll meters, causal elements, and one response parameter, Phosphorus and nitrogen (N) are the main culprits of cul- chlorophyll concentration (Cardoso et al. 2001). The evo- tural eutrophication in freshwaters. Thus, the deviations lution of the average concentration of total P and of the from a trophic level can be assessed with these two para- average concentration of total mineral N in the lakes
Table6. Chlorophyll a concentration, cell density and biomass of phytoplankton in the epilimnion of the lakes Como, Garda, Iseo, Maggiore and Varese†
Parameters Como Garda Iseo Maggiore Varese
Density (106/L) Mean 5.4 4.5 6.0 – 5.4 Minimum 0.3 0.2 0.1 – 0.2 Maximum 18.0 13.0 30.0 – 21.0 Biomass (mg/m3) Mean 544.0 519.0 1558.0 960 6654.0 Minimum 48.0 100.0 234.0 200 300.0 Maximum 2031.0 1500.0 6451.0 2800 36 000.0 Species number 45.0 46.0 38.0 76–80 30.0 Chlorophyll (mg/m3) 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
†See Commissione Internazionale per la Protezione delle Acque Italo-Svizzere (2001); Premazzi (2002); Dalmiglio (unpubl. data).
Table7. Zooplankton density and composition in the 0–50 m layer of the lakes Como, Garda, Iseo and Maggiore†
Como Garda Iseo Maggiore
Density (individuals/m3 104) mean – – – 3.00 minimum – – – 0.50 maximum – – – 10.00 Copepoda Mean density (individuals/m3 104) – 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 Cladocera Mean density (individuals/m3 104) – 0.30 – 0.15 Minimum 0.2 – – – Maximum 2.6 0.70 – 0.30 Species number 5.0 3.00 5 8.00 Rotatoria Mean density (individuals/m3 104) – 0.80 – 1.00 Minimum 1.0 – – – Maximum 5.3 3.60 – 5.00 Species number 17.0 21.00 8 33.00 Total species 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 mental conditions. In the following years, due to several and 4, respectively. technical (waste water treatment, load diversion) and All four lakes underwent an increase in total P concen- administrative (P ban in detergent) measures adopted to trations during the 1960s and reached their highest values prevent the onset of eutrophic phenomena, a significant at the beginning of the 1980s, with the exception of Lake decrease in P levels was registered. Since the beginning of Garda, which showed minimal modifications in its environ- the 1990s, a gradual decrease in P levels has been observed
Table8. 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 phytoplankton communities are still represented by the blue- be viewed as oligotrophic. Lake Iseo, however, shows two greens and the diatoms, even if replaced by new species. distinct trends in P concentrations: in the mixolimnion Table 6 summarizes the most recent data on phytoplankton (0–80 m layer) these have decreased to the present value of density and biomass. about 25 µg/L, while below 100 m mean values register at approximately 80–85 µg/L (Premazzi et al. 1998). Zooplankton In all four lakes, mineral N concentrations have shown a The zooplankton found in the deep Italian subalpine lakes general tendency to increase, followed in recent years by a is typically represented by: Copepoda Eudiaptomus padanus, less marked increase, or even stability. Nitrate concentration Cyclops abyssorum, Mixodiaptomus laciniatus and Mesocyclops increase would be related to an increase in N loading from leuckarti, Cladocera Diaphanosoma brachyurum, Daphnia the lakes’ catchment basin, mainly due to atmospheric inputs hyalina, Eubosmina coregoni and Diaphanosoma brachiurum, rather than agricultural, domestic and industrial sources. and Rotatoria Keratella cochlearis and Kellicotia longispina Nitrate is the most important nitrogen compound in the (Dalmiglio (unpubl. data); Manca et al. 1992; Commissione subalpine lakes (up to 90–95% of the total). The low nitrate Internazionale per la Protezione delle Acque Italo-Svizzere concentrations in lake Garda (relative to the concentrations 2001). in the other lakes) can be explained by a lesser impact of As regards studies on zooplankton, Lake Maggiore is the eutrophication on this lake. The slower water renewal time most studied environment since the last century. It was would result in a longer response time (higher resilience) used as a test site for the discussion of theories and specific of Lake Garda to an increased N load (Ambrosetti et al. problems of a complex community such as that living in a 1992). large lake. Different aspects of the composition, evolution In Table 6 the most recent data on chlorophyll a concen- and dynamics of zooplankton are detailed in a compre- tration for the subalpine lakes Como, Garda, Iseo Maggiore hensive review (de Bernardi et al. 1989). This lake would and Varese is shown. be classified as a ‘copepods lake’, because this group represents the most stable component of the populations. Phytoplankton Cladocerans are becoming progressively less abundant There are no comparative studies for phytoplankton on (from 10% to 2% in the last 10 years). These organisms would the lakes Como, Garda, Iseo, Maggiore and Varese. represent an indicator of the lake’s productivity. However, the composition of the phytoplankton communities An important feature of the zooplankton in Lake Como is would register marked similarities from one lake to another, the rise in the density of cladocerans, due to Eubosmina as regards density, biomass and species composition. A coregoni and Diaphanosoma brachiurum, that at present number of species are ubiquitous in these lakes. These represent a relevant portion of the zooplankton populations are the blue-greens Oscillatoria rubescens, Coelosphaerium (Dalmiglio (unpubl. data); Chiaudani & Premazzi 1993). kuetzingianum and Microcystis sp., the diatoms Fragilaria As concerns Lake Garda the marked dominance of crotonensis, Melosira islandica, Cyclotella sp. and Asterionella copepods (22% of the total zooplankton population) in formosa, the coniugatophytes Mougeotia sp. and Closterium respect to cladocerans (2%) represents a positive signal acutum, the cryptophytes Cryptomonas erosa, Rhodomonas for the trophic conditions. In fact, the increase in the lacustris and R. minuta, the chlorophyte Coelastrum sp. and density of cladocerans with an increase in the trophic the dinoflagellate Ceratium hirundinella (Ambrosetti et al. level (eutrophication) is a well-consolidated fact for several 1992; Manca et al. 1992; Commissione Internazionale per la water bodies (Manca et al. 1992). Protezione delle Acque Italo-Svizzere 2001; Dalmiglio Because of a lack of data, it is not possible to delineate the (unpubl. data); Premazzi 2002). evolution of the zooplankton populations in the lakes It can be concluded that during the 1990s there was a Iseo and Varese. Table 7 illustrates the most recent data on general decrease in the P concentration in the deep Italian zooplankton in the lakes Como, Garda, Iseo and Maggiore. subalpine lakes. This, in its turn, has determined a decline of the phytoplankton biomass. Concurrently, there was an Fish increase in the number of species with consequent gener- There is scarcely any published data on fish communities ation of biodiversity of the phytoplankton communities, with for the subalpine Italian lakes. Therefore, information to indi- substitution in the dominant species. However, no particular vidualize trends in the fish populations of these lakes in con- trend in biomass and chlorophyll a was evident, indicating nection with their trophic evolutions, which occurred in past a high resilience in the phytoplankton response to P load- decades, is fragmentary and insufficient. Perhaps, the most ing reduction. However, the most important taxa of the detailed studies on fish are those existing for Lake Maggiore. Italy’s Water Framework Directive 53
However, for the other Italian subalpine lakes some general change in respect to the 1980s when the catch of Alosa was considerations can be made, based on qualitative obser- the most important commercial catch. Three pelagic fish vations (Dalmiglio (unpubl. data); Commissione Inter- species (Alosa, Coregonus and Alborella) represent, on nazionale per la Protezione delle Acque Italo-Svizzere 2001). average, more than 60% of the total catches in the lake. In Table 8 are listed the species recorded in the deep lakes This is a common characteristic of the deep subalpine lakes Como, Garda, Iseo and Maggiore. that have a reduced littoral zone and a prevailing pelagic The decrease in Lake Maggiore of the total fish catch, area. from 809 t/year in 1982 to 180 t/year in 1995, has been paralleled by marked changes of in-lake P concentration. DISCUSSION From the data on fish population for Lake Como, two In order to achieve the established environmental quality periods can be identified: the first from 1960 to the end of objectives, considerable technical, administrative and eco- the 1970s, in which Cyprinids reached the highest values; nomical efforts were made. In the last decade, several agree- the second (1980s) in which a progressive increase of ments among the Ministry of the Environment, the local Coregonus and Alosa was observed. Presently, these authorities (Lombardy region and Varese province) and the represent the major component of professional fishing. It is European Commission were signed aiming to assess the observed that the presence of Salmo trutta and Salvelinus environmental benefits of planned restoration programmes. alpinus is significantly decreased in recent years. Intensive research activities were carried out and projects Since the 1990s, Lake Garda has registered a marked developed (Chiaudani & Premazzi 1990; Chiaudani & increase in the catches of Coregonus. In fact, the catch for Premazzi 1993; Premazzi et al. 1995; Premazzi et al. 1998). this fish was around 20 t/year in 1990 while six years later The reductions in P input to the lakes, due to the imple- it reached values of 140 t/year. It represents a noticeable mentation of measures mentioned above, have in several
Table9. 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
Total phosphorus Ex-ante 78.0 12.0 32.0 20.0 325.0 Ex-post 39.0 14.0 53.0 10.0 95.0 Reactive phosphorus Ex-ante 60.0 5.0 18.0 15.0 258.0 Ex-post 30.0 6.0 51.0 7.0 63.0 Mineral nitrogen Ex-ante 805.0 375.0 695.0 800.0 – Ex-post 878.0 383.0 773.0 820.0 – Nitrates Ex-ante 790.0 353.0 675.0 795.0 230.0 Ex-post 858.0 391.0 754.0 810.0 377.0 Transparency Ex-ante 4.6 7.0 6.9 7.5 1.7 Ex-post 7.9 9.0 5.5 15.0 3.5 Chlorophyll a 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
†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, objectives for water with emission standards for water resulted in favourable shifts in the phytoplankton com- contaminants), as indicated in the WFD. munities and in the chlorophyll a concentrations in the The Po River Authority has recently formulated directives majority of the subalpine lakes. Table 9 summarizes the lake intending to safeguard lake water quality by counteracting water quality before and after restoration programmes in the eutrophication of inland waters and taking into consideration lakes Como, Garda, Iseo, Maggiore and Varese. Figure 5 the lakes’ uses. Objectives to be pursued and strategies to shows the present trophic level of these lakes with respect be adopted have also been defined (Autorità di Bacino del to the natural background P level and the established water Fiume Po (unpubl. data-internal document, 1998); Autorità quality objectives. di Bacino del Fiume Po (unpubl. data-internal document, In addition to the emission limit value approach, the 2001)). regional authorities introduced the concept of receptive The trophic level cannot, however, be ignored in the defin- capacity of the water body in their Water Clean-up Plans. It ition of quality objectives. Although not ignoring water gives the possibility of fixing stringent limits, according to quality criteria for different uses, a classification of qualitative the natural lake characteristics and to the characteristics of characteristics of lakes, referring mainly to the trophic level, the contaminants (Piano Regionale Risanamento delle Acque has been set up. The evaluation of present trophic levels, 1992). This policy anticipated, in fact, the ‘combined such as oligotrophy, mesotrophy and eutrophy, is necessary approach’ of the EU (that is, the integration of quality but not sufficient. Eutrophication is not necessarily the
Fig. 5. Present conditions, water quality objectives and natural back- ground concentration of subalpine lakes Como, Garda, Iseo, Maggiore and Varese, expressed as total phosphorus concentration. , natural concentration; , final goal; , intermediate goal; , current concentration (Dalmiglio et al. 1999).
Table10. 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
Present condition 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 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 Ecological objective Phosphorus load (t/ year) 144.0 119.0 65.0 200–212 10–11 In-lake phosphorus level (µg/L) 9.4 10.5 11.5 8 25–30 Time required (year) 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 55 consequence of anthropogenic activities. Many lakes can and diversion was completed in 1994 (de Fraja Frangipane be naturally eutrophic due to their morphometric and (unpubl. data-internal document, 1977); Premazzi (unpubl. geochemical characteristics of the catchment basin. Thus, data-internal document, 1994)). the maximum objective achievable by restoration measures By the 1990s, Lake Varese was the subject of a coopera- should not necessarily be oligotrophy, but to bring each lake tive research programme among the European Commission, to a level as close as possible to its presumptive natural the Italian Ministry of the Environment, the Lombardy status. Hence, realistic management plans should establish region and the Varese province (Premazzi et al. 1995). The an ‘as close an approximation to a natural P state’ as the goals of these studies were to evaluate the trophic status maximum achievable water quality objective (ecological and its temporal evolution and to assess the environmental objective) as possible, and an intermediate minimum water benefits of restoration programmes carried out in relation quality objective (managerial objective), to be intended as a to the established water quality objectives. P level in lake water which is acceptable for the social use The water quality objective established by the Regional of the water resource (Chiaudani & Premazzi 1988) Clean-up Act (Piano Regionale di Risanamento delle Environmental quality objectives have been established Acque 1992) is to achieve a P concentration as close as after evaluating the natural P levels for each lacustrine possible to the natural background P level with an inter- environment in the Po river basin. The final ecological objec- mediate objective of 40 µg/L and a final objective of tives were quantified as an increase of 20% in the natural P 30 µg/L. concentration for oligotrophic and oligo-mesotrophic waters, The lake responded in a relatively rapid way to decreased a 40% increase in the P level for mesotrophic and meso- nutrient loadings, as scientists had predicted. A marked eutrophic lakes and 50% for eutrophic lakes. Intermediate reduction of the external P loads was observed, from managerial objectives were identified as a 40% increase in 50 t/year in the prediversion period in 1986 to 25 t/year in the natural P concentration for oligo-mesotrophic lakes and 1990, and to 11 t/year in 1997, as a result of the completion an 80% increase in the P level for eutrophic waters (Passino of the depurative measures. The residual P load represents et al. 1999). Table 10 compares the present situation of the no more than 18% of the total P load generated in the catch- subalpine lakes with the above objectives. ment basin: 75% is of diffuse origin. The data from Dalmiglio et al. (1999) show a relative By 1999, noticeable differences occurred. Total P improvement in the condition of lakes Como and Varese, decreased from 290 µg/L to 120 µg/l, Secchi disc trans- whereas Lake Iseo seems to have deteriorated in the last parency increased from 1.8 m to 3.2 m and epilimnetic 10 years. The condition of Lake Garda is quite stable, indi- chlorophyll decreased from 27 µg/L to 12 µg/L. Nitrogen cating the high resilience of the largest Italian lake. In Lake was no longer limiting after restoration efforts. It had Maggiore the ecological objectives have been achieved. become a limiting nutrient because of the large biomass of The results of this research, coupling the combined algae produced by increased P loads. Nuisance blooms of approach to the environmental benefit assessment, should algae were no longer a threat to the lake as in the previous contribute to the improvement of water policy, making it periods (Premazzi 2002). more effective in restoring and safeguarding the lake However, mathematical models predicted quite a long environments. time (25–30 years) to attain the best P concentration at the equilibrium (40–45 µg/L), even higher than that considered Case study: Lake Varese to be the final restoration objective for the lake. These Lake Varese was first impacted by raw sewage (domestic and models recognized the importance of internal P loading in industrial) from Varese agglomeration early in the 1960s. maintaining biological productivity of the lake (Rossi & Deteriorating water quality from algal blooms was reported Premazzi 1991). Diversion of cultural nutrient loading, in the press (Editor, 1963; Giuliani, 1997)and the scientific although essential, may not be sufficient to return the lake, community addressed related issues (Vollenweider 1965). suffering significant internal loads, to its undisturbed con- By 1965, public concern had resulted in initiatives to dition. Curtailment of internal loading may be also required. form a local agency (Consorzio Volontario di Tutela e Lake scientists predicted that the application of the in-lake Risanamento delle Acque) to address the problem of the measure such as hypolimnetic withdrawal would accelerate lake’s management. The project, promoted by the action of lake recovery by controlling P release from anoxic sedi- the Varese province in 1967, included (i) a sewerage network ments (Premazzi 1994). (ii) an O-ring sewage diversion system, and (iii) a central- By the summer of 2000, siphoning the nutrient-rich deep ized wastewater treatment plant with phosphorus and nitro- waters from the lake was effective because scientists con- gen control. Waste waters received tertiary treatment in 1986 vinced the authorities and the public that Lake Varese would 56 G. Premazzi et al. become better in a shorter time than predicted from natural and artificial lakes. The status of lakes is assessed loading models. In fact, scenarios for improving the lake through the observation of a number of elements that water quality would suggest a reduction of the total P con- include biological elements, hydro-morphological para- centration in the lake water up to approximately 25–30 µg/L meters and the physicochemical condition of the water after a few water overturns (10–15 years). This calculated (Table 11). equilibrium concentration is to be considered the closest In order to assess whether a lake falls within the appropri- value, realistically attainable, to the natural background level ate category of ‘water status’, member states will have to (20 µg/L). Preliminary results are greatly encouraging: carry out sufficient monitoring of all these characteristics it appears that the greater the amount of phosphorus as a minimum requirement. The acquired data is then used discharged in this way, the greater is the decline in P to place the water body in one of the three quality classes, concentration in the upper water layers where algae high, good, or moderate, as defined in Annex V of the WFD grow (Premazzi, unpubl. data). (European Communities 2000). ‘Good status’ is generally described as a situation where the values of the biological FINAL CONCLUSIONS elements for a lake type show evidence of the impact of Ideally, the knowledge about the water status of lakes human activity but deviate only slightly from those normally would derive from monitoring and classification as set associated with the lake type under undisturbed conditions. out in legislation, of which the Italian decrees are a good Thus, the results of the monitoring systems will be example, and even from more comprehensive information expressed as the ratio between the observed biological as required in the WFD. The WFD obliges member states parameters in a lake and the expected numerical value to provide information on the status of their lakes and to for the pristine reference condition for that type of lake assess long-term changes brought about by natural and (ecological quality ratio, EQR). anthropogenic activities through a number of monitoring Conscious of the lack of experience in the use of many obligations (surveillance monitoring). The Directive also biological elements for classification purposes as specified requires member states to set quality objectives for both in Annex V of the WFD, the European Commission
Table11. 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).
Table12. 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 57
(Directorate, General Environment) set up in 2001 a work- Belgium indicates that nutrients are not in the country’s ing group on intercalibration (led by the Joint Research national monitoring programmes. Centre, Ispra). It aims at obtaining common understanding Greece reports that the national research infrastructure of ecological status of the surface waters all over the EU and is currently inadequate to meet the principal obligations that at ensuring comparability of the EQR scales (that is, the WFD places on the country. good ecological quality should have the same ecological Most of the existing experience of lake management meaning throughout the EU). Establishing comparable refers to the problem of eutrophication, as recently reviewed class boundaries for four categories of natural waters is by Cardoso et al. (2001). There are numerous data sets crucial in order to have an equal level of ambition in available for specific lakes as a result of long-term studies achieving ‘good status’ of the surface waters in different carried out by research organizations and universities to member states. The intercalibration exercise, developed assess trend evolution in the trophic state of lakes. In within the Common Implementation Strategy of the WFD, practice, the data as required by the WFD is scarce and the should be completed by June 2006 and results published by application of the new concept of ‘ecological status’ is a December 2006. largely unknown issue. This is a new concept to water However, the reality between the member states’ quality/quantity management and arises from consideration knowledge of their lakes’ quality status and the national that natural environmental conditions vary throughout the monitoring and classification systems is very different. EU. This must be taken into account in any water’s planning The above overview for the Italian subalpine lakes, result- project. ing from a collation of information from several sources, Management plans for lakes need to be refocused including the national monitoring programmes, gives us because these surface bodies are often seen as a quite an idea of the shortage of data, especially for biological separate issue in river basin management. The WFD elements, in comparison to the requirements of the WFD. changes this attitude in that lakes must be considered as These lakes are amongst the most surveyed in Italy, but ecological entities to be accounted for in any river basin despite that, we would conclude that the current monitor- plans. ing and classification system does not comply, on the whole, The need to reformulate the national monitoring networks with the WFD. (and the classification systems) to include all the elements Yet, the situation in the rest of the EU is no better than that the WFD oblige member states to monitor, looks set to in Italy. Preliminary results from a questionnaire by the be a must for all EU countries. On the other hand, there is REFCOND Project (European Commission 2002) show not much time left to do it: surveys should be completed by that, even for the simplest quality elements (nutrients), there 2004 and in 2006 the monitoring programmes should start. are only three member states for which monitoring of Before these dates, member states will have to design their these in existing national classification systems is monitoring programmes and enact monitoring network(s) compatible with the WFD requirements (Table 12). able to carry out the sampling of all the elements in the WFD The table shows that Italy and Sweden are two of the com- with the appropriate density and frequency. These are major plying member states regarding the monitoring of nutrient tasks for such a short time available, and hopefully, there concentrations in lakes with more than 0.5 km2 surface area will be progress from the current situation, where the and the classification of these considering its deviation requirements of the WFD are still an ideal, to reality in due from reference (natural) nutrient values (National Board of time. Waters and the Environment 1988; Wiederholm 1989; Swedish Environmental Protection Agency 1991; Andersen REFERENCES et al. 1997; Brunel et al., unpubl.data-internal report, 1997; Agence de l’eau (2000a) Systeme d’evaluation de la qualitê Vouristo 1998; Passino et al. 1999; Agence de l’eau 2000a; biologique des cours d’eau. Principês generaux. Les Agence de l’eau 2000b). Etudes des Agences de l’Eau. Version 0. No. 7. The Scottish approach to lake classification identifies Agence de l’eau (2000b) Systeme d’evaluation de la qualitê four classes of water quality and establishes standards for biologique des cours d’eau. Principês generaux. Les each of the classes. The water quality change associated with Etudes des Agences de l’Eau. Version O. No. 72. nutrient enrichment is determined by the ratio of current Ambrosetti W., Barbanti L., Mosello R. & Pugnetti A. (1992) and hindcasted total P concentration. Limnological studies on the deep southern alpine lakes Finland partially complies with the WFD because it Maggiore, Lugano, Como, Iseo and Garda. Mem. Ist. Ital. monitors nutrients on the basis of water uses, but does not Idrobiol. 50, 117–46. classify by comparing with reference conditions. Andersen B. et al. (1997) SFT Veiledning. No. 1468. 58 G. Premazzi et al. de Bernardi R., Manca M. & Giussani G. (1989) Zooplankton Editor (1963) Salvare il lago di Varese. La Prealpina 1 July. in Lake Maggiore: an overview. Mem. Ist. Ital. Idrobiol. European Commission (1996) European Community 46, 103–23. environment legislation. Volume 1-General policy. Cardoso A. C., Duchemin J., Magoarou P. & Premazzi G. Office for Official Publications of the European (2001) Criteria for the identification of freshwaters Communities, Luxembourg. subject to eutrophication. Office For Official Publications European Commission (2002) Common implementation of the European Communities, Luxembourg; European strategy for the Water Framework Directive. Working Union Report 19810. group 2.3. Guidance on establishing reference conditions Chiaudani G. & Premazzi G. (1988) Appraisal of the possible and ecological status class boundaries for inland surface methods of combating the threat of eutrophication in waters. Draft Report. Community waters. Ing. Amb. 7. European Communities (1976) Directive 76/464/EEC on Chiaudani G. & Premazzi G. (1990) Il lago di Garda: pollution caused by certain dangerous substances dis- Evoluzione trofica e condizioni attuali. Office For Official charged into the aquatic environment of the Community. Publications of the European Communities, Luxembourg; Official Journal of the European Communities. L129. European Union Report 12925. European Communities (1979a) Directive 79/869/EEC Chiaudani G. & Premazzi G. (1993) Il lago di Como: concerning the methods and frequencies of sampling Condizioni ambientali attuali e modello di previsione and analysis of surface water intended for the abstraction dell’evoluzione della qualità delle acque. Office For of drinking water in the Member States. Official Journal Official Publications of the European Communities, of the European Communities. L 271. Luxembourg; European Union Report 15267. European Communities (1979b) Directive 79/923/EEC on Chiaudani G., Premazzi G. & Rossi G. (1986) Problemi e the quality required of shellfish waters. Official Journal metodi nei piani di risanamento di tutela e gestione delle of the European Communities. L 281. risorse dei grandi bacini lacustri: il caso del lago di Como. European Communities (1997) Treaty on European Ing. Amb. 9, 503–10. Union. Official Journal of the European Communities. Commissione Internazionale per la Protezione delle Acque C 340. Italo-Svizzere (eds). (2001) Ricerche sull’evoluzione del European Communities (2000) Directive 2000/60/EC of the Lago Maggiore, Campagna 1999. Regione Lombardia, European Parliament and of the Council of 23 October Milan. 2000 establishing a framework for Community action in Consiglio Nazionale delle Ricerche Istituto di Ricerca sulle the field of water policy. Official Journal of the European Acque (1984) Castato dei laghi Italiani. Volume 1-Italia Communities. L 327. settentrionale, parte prima. Consiglio Nazionale delle Giuliani G. (1997) Lago di Varese, ecco i soldi. La Prealpina Ricerche Istituto di Ricerca sulle Acque,Rome; No. 72. 30 July. Dalmiglio A. et al. (1999) The scientific and administrative Manca M., Calderoni A. & Mosello R. (1992) Limnological approach to lake management in Lombardy region research in Lake Maggiore: studies on hydrochemistry (Northern Italy). In: Lake 99 Sustainable Lake and plankton. Mem. Ist. Ital. Idrobiol. 50, 171–200. Management. (ed S. E. Jorgensen) pp. S14A–3. Ministry of the Environment (ed). (1997) Relazione sullo Proceedings of the 8th International Conference on the stato dell’ambiente. Istituto Poligrafico e Zecca dello Stato, Conservation and Management of Lakes, Vol. II, May Rome. 17–21, 1999. DIS Congress Service Copenhagen, Mosello R., Calderoni A. & de Bernardi R. (1997) [Research Copenhagen. on the evolution of the deep southern alpine lakes per- Decreto Legislativo (1999) Disposizioni sulla tutela delle formed by the CNR–Istituto Italiano di Idrobiologia.] acque dall’inquinamento e recepimento della direttiva Documenta Ist. Ital. Idrobiol. 61, 19–32. (In Italian.) 91/271/EEC concernente il trattamento delle acque National Board of Waters and the Environment (1988) reflue urbane e della direttiva 91/676/EEC relativa alla Classification of the usability of watercourses based on protezione delle acque dall’inquinamento provocato dai water quality. Publications of Water and Environment nitrati provenienti da fonti agricole, DL No. 152, No. 124. Administration. Helsinki. Decreto Legislativo (2000) Disposizioni correttive e integ- Passino R., Chiaudani G., Giovanardi F. & Premazzi G. (1999) rative del decreto legislativo, No. 152 (11 Maggio 1999) Management of great subalpine Italian lakes by the Po in materia di tutela delle acque dall’inquinamento, a River Authority. In: (ed. S. E. Jorgensen) pp. S7A–9. norma dell’articolo 1,comma 4, legge No. 128 (24 Aprile Proceedings of the 8th International Conference on the 1998), DL No. 258, No. 218. Conservation and Management of Lakes, Vol. I, May Italy’s Water Framework Directive 59
17–21, 1999. DIS Congress Service Copenhagen, Repubblica Italiana (1989) Norme per il riassetto organiz- Copenhagen. zativo e funzionale della difesa del suolo. No. 183. Piano Regionale di Risanamento delle Acque (1992) Piano Repubblica Italiana (1994a) Disposizioni in material di Regionale di Risanamento delle Acque: Criteri di pianifi- risorse idriche. No. 36. cazione in rapporto alla gestione delle risorse idriche Repubblica Italiana (1994b) Conversione in legge, con lombarde. Regione Lombardia, Milan. modificazione, del decreto-legge numero 496 (4 Piontelli R. & Tonolli V. (1964) Il tempo di residenza Dicembre 1993), recante disposizioni urgenti sulla delle acque lacustri in relazione ai fenomeni di riorganizzazione dei controlli ambientali e istituzione arricchimento in sostanze immesse, con particolare dell’Agenzia Nazionale per la Protezione dell’Ambiente. riguardo al lago Maggiore. Mem. Ist. Ital. Idrobiol. 17, No. 61. 247–66. Rossi G. (1991) Modelling lake pollution. Office For Official Premazzi G. (2002) Lago di Varese: Primo biennio di Publications of the European Communities, Luxembourg; attività degli interventi diretti (2000/2001). Relazione European Union Report 13998. presentata al convegno Il risanamento del lago di Rossi G. & Premazzi G. (1975) On the calculation of the Varese: questi i risultati. Università dell’Insubria, Varese. mean residence time in monomictic lakes. Idrol. Sci. Bull. Premazzi G., Cardoso A. C., Rodari E. et al. (1998) Il lago 20, 575–88. d’Iseo: Condizioni ambientali e prospettive di risana- Rossi G. & Premazzi G. (1991) Delay in lake recovery mento. Office For Official Publications of the European caused by internal loading. Water Research 25, Communities, Luxembourg; European Union Report 567–75. 17720. Swedish Environmental Protection Agency (1991) Quality Premazzi G., Chiaudani G., Pereira A., Rodari E. & Rossi G. Criteria for Lakes and Watercourses. Naturvårdsverket. (1995) Lago di Varese: condizioni ambientali e soluzioni Vollenweider R. A. (1965) Materiali ed idee per una idro- per il risanamento.Office For Official Publications of the chimica delle acque insubriche. Mem. Ist. Ital. Idrobiol. European Communities, Luxembourg; European Union 19, 213–86. Report 16233. Vouristo H. (1998) Water quality classification of Finnish Regione Lombardia–Commissione Europea (1997) Studi inland waters. Eur. Water Manage. 1, 35–40. finalizzati alla definizione degli strumenti per l’ottimiz- Wiederholm T. (1989) Assessment Criteria for Lakes and zazione delle procedure di pianificazione, gestione e Watercourses. Background document No. 1. SVN Report tutela delle risorse idriche. Convenzione Rapporto No. 3627. Finale. CCR-Ispra, Direzione Generale, Ispra; No. 12635–97–02. 2001.