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The National Environmental Impact Assessment Commission (VIA): Why the MoSE does not work
21 Agosto 2005
Venice and its Lagoon (english translations)
The original title is “Summary conclusions of the review made by the Commission for the assessment of environmental impact about the general project of the interventions at the lagoon mouths to regulate the tide flows”. It is the document delivered to the Ministry of the Environment in December 1998.

Following this document, on the 24th December 1998 the Ministry of the Environment and the Ministry of Cultural Heritage have issued a decree (the so-called Ronchi-Melandri decree), which rejects the project and defers it after other more priority operations. The Veneto Region has made an appeal and won its claim at the Tribunal for Regional Administrative Affairs (TAR) due to formal mistakes in the decree. However, the TAR decision does not affect the content of the VIA commission’s conclusions that point out doubts and concerns about the MoSE, and are still valid and satisfactory.

The Commission believes that the safeguard of Venice cannot be pursued outside a more general management of the lagoon system, meaning the whole of the draining lagoon basin and the large rivers flowing in the same lagoon, the coast and sea sector between the mouths of the Adige and Brenta rivers, the lagoon mouths, the lagoon basin and its morphologic and anthropic units: because the events that occur in all these elements undergo a complex and non linear interaction.

The Commission believes that the Project, by combining into a single action and typology all the operations to reduce the ordinary high tides and the interventions aimed at regulating the exceptional “high waters”, also through manoeuvrable barriers at the port mouth to regulate the tides and therefore implying an increasingly higher number of closures, is not able to manage the most frequent average-high tides, if not to the detriment of the port activities and the open and continuous exchange between sea and lagoon.

The Commission believes that the management of the continuous exchange between sea and lagoon is one of the unavoidable elements to recompose and maintain the fragile and instable equilibrium between the sea and the mainland environment, from which it comes from.

This equilibrium between fresh and salted waters is not merely a morphologic and hydrodynamic condition, but is the reason for the very survival of the environmental and anthropic mosaic that defines the nature of the lagoon.

The Commission believes that this equilibrium can only be obtained with an articulated combination of works and actions respecting the characteristics of experimentation, reversibility and gradualism concurring to the achievement of this scope.

Therefore, the Commission deemed indispensable a strict connection between the project evaluation and the Action Plan for the morphologic recovery of the lagoon elaborated proposed within the Licence of the Water Magistrate.

Following the above considerations, the Commission negatively notes that the Project lacks of research and does not define the environmental indicators on which to target the operations and work planning.

As regards the Morphologic Recovery Plan, the Commission deems appropriate but not sufficient the contrasting action started off by the Action Plan for the morphologic recovery of the lagoon.

The Commission believes that the objectives stated by the Proposer of the Action Plan for the morphologic recovery of the lagoon are not fully undertaken, and the actions to achieve them are contradictory and unable to guarantee the dynamic equilibrium in the long term.

The Commission negatively remarks that the Project lacks an explicit discussion about the evolution process that - following the not only morphological operations proposed – would have to lead to a new condition of the lagoon dynamic equilibrium. Nor the general Plan for the morphologic recovery of the lagoon, nor the SIA provide adequate analytical references on this respect.

The Proposer states – having not provided any evidence or demonstration – that the erosion of the lagoon-beds and sandbanks is a more relevant event than the overall deficit of sediments in the lagoon: the Commission deems this evaluation misleading. The project renounces to pursue the cancellation of this deficit as a priority: as a result, it is not clear which kind of rebalance it wants or it can achieve.

The Commission believes that the indifference of the actions proposed in terms of regulation of both the river and the drainage waters and the volumes of the tides exchanged at the mouths cannot be assumed as a criteria of acceptance in the comparison among the various possible solutions, nor as a criteria to optimise the same Project, until the current condition of the lagoon morphological evolution is not experimentally verified and the action plan is not proven effective, in order to aim at:

• the annulment of the deficit in the exchanges of solid material between the lagoon basin subsystem and the other subsystems;

• the determining of sections of equilibrium in both the lagoon and the mouths channels;

• the lagoon rebalance and the restoration of resilience conditions and vitality in the lagoon ecosystem,

Therefore, the Commission believes that is absolutely necessary to proceed with such verifications and critical review, of both the hydrodynamic, morphological and environmental indicators that can define the re-equilibrium objectives, and the effectiveness and consistency of the numeric models proposed.

In conclusion, the Commission believes that:

a) the Project does not assure the pursuing of the objectives stated in the Plan for the morphologic rebalance. In fact, the same Proponent puts the project on a different level and thus does not contribute the rebalance;

b) the Project can be incompatible with the potential necessity of implementing further actions at the mouths, in order to pursue the restoration of the lagoon morphology and overall protection. The Commission finds this necessity probable. The incompatibility comes from the Project philosophy to pursue the greatest possible uniformity in terms of management, thus avoiding the need to integrate it with other possible actions. This provides the Project with the characteristics of experimentation, reversibility and gradualism that are required by the sentence of the Higher Council of Public Works n.209 1982 aimed at the good integrated management of the lagoon system.

The Commission deems necessary to adapt all the proposed actions and all the other actions that can contribute to the integrated management of the lagoon system and to the cooperative capacity needed for:

• maintain the balance between freshwater and seawater,

• improve the capacity of intercepting the lagoon sediments,

• maximise the transfer of solid material from the sea to the lagoon to guarantee safe maritime traffic, and from the lagoon to the mainland by checking the eutrophic agents.

Regarding wide-spectrum actions

The Commission believes that the set of actions foreseen by the special legislation constitutes the indispensable starting point for the lagoon morphological rebalance.

The Commission, although believing that wide-spectrum actions are more functional to the management of the morphological evolution, thinks that they are not alternative to the regulation of the tide flows through operations at the mouths, considering that their overall contribution to the reduction of the tide levels in the lagoon must be maximised in any case.

Therefore, the Commission believes that any kind of action for tides regulation imposed on the lagoon mouths must integrate with wide-spectrum actions deemed useful for pursuing the objectives stated in the special legislation for Venice.

The Commission evaluates that:

• all the actions to revitalise the most inner parts of the lagoon are positive and adequate;

• the activity to keep inside the lagoon the materials removed by the navigable channels through the restoration of morphological structures is appropriate. However, greater attention must be paid to their re-naturalisation and environmental consolidation;

• overall the closure of the straight trait in the channel Malamocco - Marghera and the reopening of the Fisolo Channel do not bring significant changes;

• the artificial continuous bringing of sediments into the lagoon deserves deeper consideration and generalisation.

The Commission deems that a re-calibration of the dissipative capacity of the channels at the port mouths is essential, especially with an appropriate composition between the mouths depth and shallowness, in order to both reduce the level of the most frequent tides in the lagoon, and to increase their capacity to intercept the sediments. All this must be carried out following principles of experimentation, reversibility and gradualism, by managing at the same time the process of rebalance of the channels sections and the process of consolidation of the lagoon morphological units.

The Commission believes that the modifications to the piers presented by the Proponents are harmful and inadequate.

Regarding the draining basin

The Commission believes that the regulation of the superficial natural and reclaimed hydrography flowing in the lagoon is indispensable; this regulation must be put to the defence of the anthropic activities in the draining basin, to minimise the water volumes that, by flowing into the lagoon, contribute to determine composite events of exceptional “high waters”, and to pursue the maximum sustainable bringing of freshwater and sediments to the lagoon basin.

If no actions for the water regulation of the draining basin will be carried out, should exceptional events occur, like in 1966, huge water quantities would be introduced into the lagoon from the mainland, in spite of the project movable barriers. The feasibility of the hydro-regulation actions is not yet proven but is, however, an indispensable pre-requisite to state that the proposed works can protect Venice from exceptional events.

Therefore, the Commission believes that the raising of the minimum levels of the inhabited areas of the lagoon is anyway necessary, in order to protect these areas by the water flows of the hydrographic system and of the draining basin, and to reduce as much as possible the failures in any type of system for the reduction of the recurrent tides. The Commission believes it is a priority to increasingly raise the urban settlements in the lagoon up to the maximum possible level, with the best available technologies.

The Commission believes that this action is necessary and it remains a priority even if the examined project should be implemented.

Regarding the project reliability: the forecast system, the rises in the lagoon and the movable bars resonance

The Commission believes that the Project does not sufficiently guarantee the achievement of the stated objectives, because it strongly depends on the forecast systems.

The Commission believes that the confidence gap of the current forecast for average-high and exceptional tides ahead of 3 to 6 hours is still significantly large compared to the lagoon tides and the high waters events. In fact, this gap of approximately ± 20 cm, includes all the normal fluctuations of the tides and of all the events of soil submersion at + 100 cm with a return time of 1 year.

In particular, the Commission finds that the achievement of the following two main objectives is in doubt:

• to block the flooding of the inhabited areas at +100 level, within the SIA forecast of frequency and time length

• a sustainable number of closures or announced closures, in particular for the port system

The Commission also believes that the proved sensitivity of the “high water” events to the local weather conditions, together with the verified progressive increase of the entity and rapidity of short and medium term weather phenomena and their complexity, of both tide and hydrological type, makes the forecast system one of the most crucial factors for the operative effectiveness of the examined Project.

The Commission believes that the Project does not adequately deal with compound tide events, because long-lasting or frequent closures of the mouths can:

• put the environmental system under cumulative stress, for at least 24 hours;

• increase the risk of possible failure of the forecast system;

• decrease the possibility to forecast the rise in the lagoon water levels after the closure of the movable barriers, due to wind forces, direct rain, superficial hydraulic networks draining and flowing into the lagoon and the quantity of water initially flown into the lagoon.

The Commission believes that the Proponent underestimates the overall maximum rise, due to an incomplete estimation of the possible flows from the mainland to the lagoon, of the direct rain, and also due to an underestimation of the sirocco and bora winds (south and north).

The Commission assesses that with high frequency wavy motion, the system could likely fail due to its resonance, resulting in a significant increase of the flows into the lagoon from the traferri and the additional stress to the anchoring and foundations systems.

The Commission agrees with what the Expert Committee has already pointed out, that the physical studies and modelling have not reproduced the most serious conditions that can more easily generate this resonance. Thus, the system does not seem sufficiently tested and reliable.

The Commission also notes that the system of underwater structures (bars, hinges, joints, etc.) looks weak in comparison with the aggressiveness of the physical and biological agents. At the moment, there are no such structures that, under water for a long period of time, can be defended by the physical and chemical deterioration and from the micro-fouling bio-deterioration. Therefore, the bio-deteriorating action is unpredictable and the upholding requirements cannot be estimated.

Regarding the local security

The Commission believes that the a priori decision to set the level of the local security at +100 cm s.I.P.S. in Venice and Murano is groundless.

The Commission believes that the implementation of a system of integrated technologies is the priority, in coordination and synergy with the twenty-years extraordinary upholding programme already agreed by the City of Venice, the Veneto region, the Water Magistrate, according to art. 5 of Law 5 February 1992, n.139.

This programme, in consideration of all the different structural situations, is currently the most suitable operation in order to maximise the benefits provided by local security actions with the local population consensus, as it sets the level of public pavement at +120 cm s.I.P.S. and at over +160 cm s.I.P.S. the level for residential security.

The Commission deems that the Municipality of Venice assessment on this plan feasibility is reliable, with an overall cost of approximately 118 billion liras in addition to the cost already budgeted for ordinary urban upholding.

The Commission wishes that such technologies would also be extended to non-residential building units.

The Commission believes that also the so-called “MacroInsulae” project, an intervention of perimetral protection with fixed and mobile devices for groups of islands, deserves attention and further development.

This solution looks potentially effective and simple. It can protect from high waters up to the level of +140 cm s.I.P.S., similarly (and even better) to what already implemented in Malamocco.

The Commission positively evaluates the experiences of ground-rises between +110 cm and +120 cm s.l.P. S. in case of architectural, historical and monumental goods and believes that the level of +100 cm s.l.P.S. is the maximum protection level possible to respect the monumentality of St. Mark and Rialto islands.

The Commission negatively remarks the Proponent’s lack of in-depth analysis, about consolidated or experimental technologies for territorial rise, deep or shallow.

Currently, the most mature and potential technologies are the confined superficial lifting and the pressurised re-injection in deep acquifers. The Commission deems useful and necessary to update these actions feasibility studies through further research and tests, also in view of the potential growth of the average sea level due to eustatic phenomena.

The Commission believes that the results obtained by rising security levels must be evaluated, not only in terms of floodable urban surface reduction, but, most of all, in terms of reduction of the average frequency of flooding occurrences.

Regarding costs/benefits and interference with port activities

The Commission negatively remarks the fact that the Project does not provide an assessment of the economic and environmental impact resulting from the restoration of the main and secondary hydrographic networks.

The Commission thinks it is wrong to consider recovery and morphologic rebalance costs as loss, in terms of variations to the current lagoon state, because the current morphologic state of the lagoon is not balanced and cannot represent the ultimate objective of the hydrological rebalance, nor of the morphologic recovery of the lagoon. They both must be considered inevitable costs for the lagoon conservation.

The rise of the lagoon inhabited areas to higher levels and the decrease of the tide levels due to morphologic interventions, determines a reduction in the risk of flooding and damages that cannot be overlooked in the overall evaluation of the option “T”, i.e. the comparison term to which refer the assessment of the proposed Project impact and benefits.

During the work in progress, both the Port Authority and the Harbour’s Master of Venice have underlined that the Proponent’s project forecast and specific simulations do not sufficiently reassure on the actual possibility of maintaining – during the works – the usual level of maritime traffic through the Mouths, nor do they guarantee adequate shipping safety.

There are risks for the port activity deriving from the increased number of closures and of notices of closures, even if not followed by actual closures.

Regarding the environmental impact

In order to evaluate the Project possible effects on the involved environment, the Commission has considered the exceptionality of the given ecosystem, deriving from the combined action of natural and anthropic factors over a number of centuries, unique for its structure and its functional rules.

The Commission notices that this exceptional value is also been recognised with special acts on an international, national and regional level. Bearing in mind that for its assessment the Commission has deemed indispensable to take into account the spatial and temporal articulation of the system, at least three important components should be evaluated, both separately and in their mutual interrelations: the lagoon, the city of Venice, the draining basin.

The Commission has also verified that within this system there are other particularly significant naturalistic and ecosystemical areas, such as the shore cordon at Cà Roman and the area of velme in Bacan.

The Commission acknowledges the special conditions of the system dynamic equilibrium, that in the past have allowed to assimilate the pressures produced by the human action with the consequent preservation of both the main ecologic functions (balancing between erosive and deposit actions, equilibrium among the various levels of ecologic production, conservation of specific elements of biodiversity, etc.), and the diversified fruition exercised by the Venice population. The Commission also acknowledges that this dynamic equilibrium has been infringed during the present century, because of increased highly stressful anthropic activities on the environment.

The Commission evaluates that the SIA methodological framework cannot be considered correct and exhaustive for this case study, because:

• the indicators have been selected according to imprecise criteria and difficult to use forecasting variables, mixing forecasting indicators with control criteria, and sometimes using inappropriate indicators for the concerned evaluation;

• the SIA contains some serious analytic deficiency, for instance there no in-depth analysis is provided on the most environmentally sensitive sites involved in the proposed works. In addition, some significant impacts have not been properly assessed, such as the effects on the hygienic-sanitary situation on the city of Venice;

• the overall evaluation picture lacks a parameterisation of the indicators and a quantitative estimation of the related impacts. These would be prerequisites to formulate a comprehensive assessment of the expected effects.

The Commission has verified, on the basis of the wide amount of available information, that the Project implementation would involve serious impacts during the carrying out of the works, such as:

• significant amounts of priority environmental units (only roughly defined by SIA) that host important species for the ecosystem biodiversity would be used, such as the Cà Roman coast;

• environmental units, such as the Bacan velme, will be significantly affected, although they represent a fundamental and internationally valuable site for the lagoon ornithofauna;

• there will be significant alterations to the current landscape, as the same SIA underlines, among which the building of a large artificial island at the entrance of the Lido mouth,

• there will be general pressures and alterations connected with the size of the construction site (thus quite large). On this regard, we need to mention that approximately 8 million tons of stone material coming from distant - and sometimes very far – quarries will be used, that existing pieces of work will be demolished (piers at the Malamocco and Chioggia mouths) for 350.000 cubic mts., and that the sediment dredging, movement and unloading will overall involve approximately 5.000.000 cubic mts. of material and because of that a particularly large shipping fleet will need to be used;

• the whole construction works will last 8 years, if the estimation is respected; the impacts produced on each involved area will last for years with potentially combined effects, which the SIA does not take into consideration. Should the resources will be scarcer in the future, this estimation of time length will not be respected

• in this case, the construction site could insist in the area for more than 10 years, with a consequent prolonging of the impacts.

Again on the environmental implications of the Project implementation, the Commission also believes that:

• the high variability of the geotechnical characteristics of the sediment area would have needed more direct research on the subsoil, in order to establish more precisely the subsiding in each point of the dam profile and to be able to estimate how will the soil behave under the weight of the proposed work;

• it stands out quite clearly that the work represents a very much intrusive intervention in the shores physical-morphologic context, and that in its present design it does not have characteristics of reversibility;

• modification of substantial parts of the work, should in the future arise the need to modify the mouths profile to ensure continuous openings between sea and lagoon, as the Committe points out, would imply significant demolitions or the building of further structures in areas and sites other than the port mouths;

• the consequences and costs of a possible dismissal or abandonment of the work, before or at the expiring of its lifetime , have not been assessed, nor the very problematic aspect of how the galleries and sites will be upheld has been clarified. The same Proponent, and the Higher Council of the Public Works, states that these galleries are a breeding-ground for methane gas, and thus require continuous air conditioning;

• the examined proposed operations are so relevant that, as also the Expert Committee notices, would require considerable demolitions and would constitute an expensive and technologically complex enterprise, having the construction sites to work in difficult weather and sea conditions.

The Commission has verified that the Project and the SIA do not include adequate interventions of mitigation and/or compensation.

The Commission considers that the analysis has highlighted the possibility of highly critical environmental risks in case of very frequent successive closures, or in case of a high number of closures during per year (possibility assumed for the future in order to justify the need to implement the project):

• there could be a significant increase of the risk of anoxic crisis in important lagoon areas, both in terms of ecosystem and in terms of aquaculture activities;

• the regulation of the high waters, obtained with the closure of the Port mouths, will reduce the exchange capacity between sea and lagoon , thus diminishing the possibility to dilute the lagoon pollution. The concentration of some particularly dangerous substances, such as zinc, will significant increase;

• as far as it is known by now, the interruption of the water exchange between sea and lagoon must be considered highly risky in terms of hygienic-sanitary conditions in Venice. As it is well known, the depuration of potentially dangerous urban waste is currently based on the environmental system self-capacity of significantly reducing the factors of microbiological risk, through various self-depuration mechanisms that depend on the city channels quality and good keeping.

The Commission considers that the above-mentioned impacts and risks will be particularly aggravated by the current critical lagoon vulnerability.

In the current conditions the “interconnected city/lagoon/territory” ecosystem must be considered fragile, scarcely resilient and thus potentially unable to face new significant stress. Its resilience is scarce and thus the priority precondition for any type of intervention must be the completion of the programmes of ecological consolidation, which the institutions have already started off, such as:

• the Recovery Plan of the Veneto Region to minimise the waste of nutrients coming from the draining basin. This objective has not yet been achieved. Achievement is forecasted for year 2020;

• the effectiveness of the self-depuration processes, that currently allow a reduction of the risks connected with urban waste, must be better guaranteed. Thus, the City of Venice must conclude the current channel cleaning work in progress.

• the lagoon morphology recovery objectives must be completed, together with the recovery of the related mosaic of sandbanks and velme, also through a review of the quality and effectiveness of the first actions carried out under the Special Law for Venice;

• the Special Law for Venice planned implementation programme must be brought forward, also in its not yet implemented chapters, such as the opening of the fishing valleys, the tides expansion and the replacement of the oil traffic in the lagoon;

• the programme of lagoon decontamination must be brought forward. The actions foreseen by the Ronchi-Costa decree must be planned and implemented.

The Commission believes that, in order to respect the general criteria of environmental receptiveness, it would be necessary to achieve the system ecological consolidation through the above-mentioned measures before executing any kind of regulation work.

The Commission has verified that nor the Project, nor the SIA have been based on scenarios that preliminarily require the implementation of the above-mentioned consolidation intervention, which could perhaps allow a better absorption of the above-envisaged impacts. Thus, the Commission believes that the Project implementation would result in erosions that are potentially critical for the remained receptiveness of the involved ecosystem.

Finally, the Commission has verified that there is not urgency connected with eustatic events that justify a rapid carrying out of the Project, because:

• as the international “Committee” of experts also points out, “in case of an increase of the sea level induced by the climate change the beginning of the phenomenon is expected to be slow”; according to the most critical scenarios indicated by the Proponent and by the same Committee the estimation is of approximately 3 cm a decade for the first 50 years;

• the eustatic trend of the last 25 years in Venice does not indicate an increase of the average sea level. For the time being, nothing confirms the hypothesis of a correlation between the increase of the planet temperature, and specifically of the Mediterranean Sea, and the increase of the eustatic levels. Thus, nowadays in Venice we are not in critical conditions as regards the eustatic growth;

• however, for the next century we cannot completely exclude even more critical scenarios of eustatism than what have been hypothesised, that would make the project dams useless. In this perspective what becomes really crucial is the activation of a serious policy of monitoring and control at the level of the whole Mediterranean basin, in order to recognise in time the real trend of eustatic growth and to take in due time the most appropriate decisions (that could also include a substantial review of the current project)

• even recently, alternative technical solutions or significant integrations to the current project have been presented. Up to now, they have not yet been comparatively evaluated nor analysed in depth. Delaying the project implementation not only would dismiss the option of regulating the port mouths, but would also allow to operate this regulation when it will really be necessary, following the results of the monitoring on the actual eustatism. This time bracket could thus be utilised to define a project that does not present the serious deficiency of the current one, and to complete the indispensable interventions of precautionary environmental consolidation, according to what has been pointed out above.

All this said and considered, the Commission believes that the proposed works cannot be considered compatible with the current critical conditions of the involved ecosystem, including the lagoon, the city of Venice and the related draining basin, for

• their inadequacy in relation to the objectives of lagoon morphological rebalance

• the lack of integration (and potential damage) with the other actions aimed at protecting Venice from average-high waters and from exceptional high waters.

• the detriment to the port activity

• the relevant and potentially irreversible environmental impacts.

10 December 1998

21 Agosto 2005

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