Sustainable management of leisure and professional fisheries at the ...

The project’s final action was to define and approve
a “Lake Contract” 2 which enables:
- “A set of rules to be adopted in which the criteria
of public interest, economic performance, social
value and environmental sustainability play
an equal role in seeking effective solutions for
restoring the lake’s environment”,
- Promoting, based on the content of Directive
2000/60/EC, the “consultation and integration
of policies at the level of the lake’s catchment
area, with the participation of all the public and
private entities in the protection and optimisation
of water resources and of related habitats, as well
as reducing the risk of flooding”,
- Developing an activities plan summarised in
the Strategic Document for Lake Iseo 3 , for
long-term interventions, shared by everyone, for
improving and dynamising the local territory.
The Strategic Document for Lake Iseo contains
an initial analysis of the territory, and of the
environmental and socio-economic stakes
affecting the lake. Three main issues have
been identified:
- The eutrophication of the lake;
- The collection of wastewater and treatment of it;
- Control of the lake level.
These issues must be resolved in order to achieve
the objectives set out in the regional law relating to
water protection and use 4 .
B. THE MAIN ENVIRONMENTAL ISSUES
As far as eutrophication is concerned, an analysis
of the pollutants in the lake provided an estimated
pollution load of 72 tonnes of phosphorus per year,
which is the equivalent of a balanced phosphorus
concentration of 16-18 mg of phosphorus per litre,
which can be achieved in 5 to 10 years.
The drop in the concentration of the pollutant
loads flowing into the lake is the result of efforts
devoted to wastewater collection and treatment,
which began in the second half of the 1990s. The
Valcamonica sector (from which wastewater flows
into the River Oglio) and certain buildings from
which wastewater flows in the Borlezza sector do
not yet have a treatment system.
Another major issue is controlling the level of
the lake. The lake waters are an energy source
(hydroelectricity) used for irrigation purposes as
well as for industrial uses throughout the catchment
area. The lake’s outlet at Sarnico must therefore
be controlled on a seasonal basis. This leads to
major variations in the lake’s level. In particular, low
levels give rise to problems for public and private
boat traffic, damage the lake ecosystem, cause
structural problems in a large part of the littoral zone
belonging to boroughs on the edge of the lake, and
contribute to the emergence of mud flats and the
draining of sectors featuring aquatic macrophytes
(with a negative impact on the landscapes and
the lake’s recreational value). To the contrary,
excessively high levels cause local flooding, make it
difficult to moor boats along wharfs, cause damage
to public and private property, problems for boat
traffic, and water seepage into the wastewater
collection networks.
Resolving these issues is a long-winded process
which, moreover, would enable the resolution of
other related disturbances:
- The proliferation of microalgae which, in late
summer, can cause temporary bans on swimming
and using the lakewater for irrigation purposes.
These proliferations take the form of red stains on
the surface of the water. There are also possible
consequences for the borough of Monte Isola,
as its drinking water supply comes directly from
the lake;
- The loosening of aquatic macrophytes from the
bottom of the lake, which then float to the surface
and are carried downstream by the current.
There are negative impacts on tourism, fishing,
and for pipes, and they are likely to cause costly
management problems;
- Disturbance of the ichthyofauna, which feels
the negative impact of eutrophication and
fluctuations in the lake level.
2
A voluntary agreement between the regional government, local authorities, and other public and private structures aimed at defining objectives,
intervention strategies, responsibilities, and the actions which will be initiated.
3
The Strategic Document for Lake Iseo was one of the main achievements of the “Coordinarsi Agire Insieme sulle Acque del Sebino” programme.
The document’s objectives were an analysis and summary of the state of the territory, environmental and socio-economic issues affecting the lake
region, and drawing up a list of 80 actions for protecting, optimising, promoting and developing the lake, in compliance with the existing planning
documents and in accordance with the local needs which emerged during the participatory process.
4
Regional Government of Lombardy DGR VIII/2244 of 29 March 2006 entitled “Approval of water protection and use, in accordance with
Art. 44 of Legislative Decree 152/99 and Art. 55, section 19 of Regional Law 26/2003”, which is the benchmark law for all operations contributing
to achieving quality objectives in Lombardy.