Exemptions according to Article 4(4) due to natural conditions: the case study of Lake Viverone (Italy)

Transcription

1 Ministry of Environment Land and Sea General Direction for Water and Land Protection Common Implementation Strategy for the Water Framework Directive Exemptions according to Article 4(4) due to natural conditions: the case study of Lake Viverone (Italy) Berlin,

2 CIS WFD Exemptions according to Article 4(4) and 4(5) due to natural conditions - Case Study: Lake Viverone CONTEXT PO RIVER BASIN PIEDMONT REGION (NW ITALY) Sites of Community Importance (SCI) and Special Protection Area (SPA) according to EU 92/43/EEC and 2009/147/CE Habitat and Birds Directives * BIELLA IVREA * Neolithic UNESCO site is DORA BALTEA RIVER BASIN MORAINIC AMPHITHEATRE OF IVREA located in a small portion of the North-Western littoral zone VIERONE LAKE CATCHMENT

3 LIMNOLOGY

4 LAKE VIVERONE as a CASE STUDY Why is this lake an interesting case study? Viverone is a natural closed lake, without significant effluents and small tributaries Groundwater flows seem to contribute to the lake hydraulic balance, but mainly through inflows Overall inflows-outflows are very scarce and the lacustrine hydraulic renewal time is estimated to be around years Physical-chemical conditions of the lake water truly reflect the eutrophic condition of a temperate, deep and impacted lake

5 LAKE VIVERONE In thepast The lake was affected by massive and multiple anthropogenic impacts that strongly contributed to the actual nutrient internal load Wastewater discharges and nutrient loads from agricultural activities have been reduced in accordance with 91/271/EEC and 91/676/EEC Directives

6 CRITICALKEY FACTORS Total Phosphorus; Ortophosphates Bottom anoxia - Bottom Redox conditions (NH3, H2S formation) Total Nitrogen The lake is not usually subject to algal blooms but it is periodically monitored to detect cyanobacterial blooms: despite eutrophic condition, water transparency is generally not a critical parameter Morphological alterations Presence of Invasive Alien Species (Fauna & Flora)

7 STATUS WFD Po River Basin District Management Plan ECOLOGICAL STATUS MODERATE CHEMICAL STATUS GOOD Main Critical indexes: Chemical physical parameters (LTLeco) Phytoplancton (IPAM Index)

8 PRESSURES and Po River Basin District Management Plan WFD Article 5 >> Annex II (Identification of Pressures - Assessment of Impact) LAKE VIVERONE Ø at risk of failing the environmental quality objectives Ø no significative pressures (many not significative) Ø existing pressure: Introduced species and diseases WISE code 5.1 (qualitative assessment)

9 IMPACTS ASSESSMENT The depicted scarcity of relevant pressures that directly relate to impacts and to unsatisfactory ecological conditions must not be considered a paradox in the case of a closed lentic water body 1 ) the effects of past or recent pressures and impacts caused by no longer existinganthropic activities, structures or behaviours are still acting and will continue to have effects in the future (e.g. as internal load in the lake) 2) multiple and various pressures and impacts insist on this water body. These cannot, however, be considered individually as significant STILL P, N TODAY EXTERNAL LOAD P O 2 MORE THAN 50 YEARS INTERNAL LOAD MOTORBOAT NAVIGATION URBAN ANTHROPIZATION villages and touristic structures CARP FISHING AREAS LAKESHORE ARTIFICIALIZATION AGRICULTURE is not extensive and is characterized by mixed crops

10 ADOPTED MEASURES Po River Basin District Management Plan WFD Article 11 >> Programme of measures q q q q q Measure code KTM01-P1-b006: this measure aims at improving the WWTP and Sewerage systems, to prevent any risk of accidental spillages into the lake. It will be completed in five years Measure code KTM03-P2-b015: these are two measures aimed at increasing the buffer capacity of the catchment area against exogenous nutrient loads, by naturalization of farmlands near the lake, with the collateral positive effect of connecting ecological corridors and ecosystem services Measure code KTM26-P5-a105: This measure is aimed at defining a local landscape policy focused on environmental protection according Regional Landscape Plan. It is strictly connected with the Lake Contract s actions Measure code KTMyy-P2-a112: this is a set of measures complementary and specular to the above described actions concerning the reduction of agricultural impacts and it takes into account the possible implementation of the voluntary measures included in the Piedmont region Rural Development Plan Measure code KTM26-P5-a107: Viverone Lake Contract is a governance mesaures

11 ADOPTED MEASURES The Lake Contract involved Piedmont Region, Biella and Torino Provinces, the basin s municipalities together with Regional Environment protection Agency (ARPA), WWT and Drinking water public utilities and local private and public citizen associations. It activated measures like afforestation areas, buffer strips, improvement of sewerage system, information and education projects to reduce nutrient input into the lake. Is a strong participated process involving all institutional actors and stakeholders. In particular, Actions, referred to the three Strategies: A Safeguard and Recovery B Sustainable development C Knowledge and monitoring

12 CONCLUSIONS JUSTIFICATION FOR APPLYING ARTICLE 4(4) ü ü ü ü ü Viverone is a deep, closed lake characterized by a very long hydraulic Renewal Time. The lack of relevant and continuative surface outflows is associated with seasonal and modest inflows The lacustrine environment still appears to be an efficient ecosystem which shows a good level of biodiversity and biomass abundance which reveal an elevate overall resilience capacity of the water-body The lake was affected, mainly in the past decades, by massive and multiple anthropogenic impacts that strongly contributed to the actual nutrient internal load cumulation Wastewater discharges and nutrient loads from agricultural activities have been reduced in accordance with 91/271/EEC and 91/676/EEC Directives However, the cumulation of exogenous, multiple and various impacts due to the sum of diversified anthropic pressures and of self-sustaining internal loads in a water body characterized by a very long renewal time, make it very difficult to achieve the good status objective by 2027

13 CONCLUSIONS WFD iii) natural conditions do not allow timely improvement in the status of the water body Lake Viverone is a highly resilient water body that needs time to achieve good status and recover its natural conditions

14 Thank you WG Ecostat) (SCG delegate)