Kouli_etal_2008_Groundwater modelling_BOOK.pdf - Pantelis ...

Groundwater Management in the Northern Adriatic Coast (Ravenna, Italy)… 209
Now it is common knowledge that any such single action will have major consequences
for the hydrology of a large area, but at the time this was not considered and so many
unwanted side effects are now causing problems to the area. For example, subsidence coupled
with river canalization and rectification caused rivers to become ‘hanging’ above the
surrounding land, strongly reducing sediment supply to the sea and consequently causing
coastal erosion along most of the Emilia-Romagna shoreline (Fig. 2b). The subsidence also
dropped most of this territory below mean sea level and has modified the river regime and the
normal groundwater flow. In this situation, a drainage system became necessary to lower the
water table and keep the land dry.
River mouth enlargement to accommodate for tourist marinas has caused extensive
landward saltwater encroachment along rivers and canals. Tourist establishments along the
coastline have destroyed the original sand dunes continuity and their natural barrier effect
(Fig. 3).
All these man-made changes (Table 1) reduced in one way or another freshwater supply
in the coastal aquifer. The result is an unstable phreatic aquifer that is not able to contrast
saltwater intrusion. Unluckily, it takes a long time (up to thousand years sometimes e.g. Oude
Essink, 2004) for any aquifer to regain a stable brackish-freshwater interface after a change
has occurred. Therefore our coastal aquifer is still responding to changes that occurred several
hundred years ago or later. This is important to realize especially when modeling studies are
performed. For this very reason we thought it important to understand and document the
hydraulic and hydrologic history of this area.
Saltwater intrusion is not the only hydrologic problem facing the area: droughts, flooding
during events of extreme precipitation, contamination of surface and underground water
resources, and over-exploitation by agriculture and tourism also need to be considered. These
problems will only worsen as current climatic changes continue (Giambastiani et al., 2007,
Antonellini et al., 2008)
Moreover another complicated issue is the fragmented and complicated Italian
bureaucracy of water management. This is historically grown along with the ad-hoc changes
in the hydraulic structure. The so-called ‘Consortium of land reclamation’ (Consortium
Bonifica) for example was called to design and execute the land reclamation starting in the
1950s. To this day, they manage the drainage of the area as well as the irrigation of the
farmland. They make decisions about the quantities of freshwater, but are an entity totally
disconnected with other political entities such as the established water shed authorities, the
Regional water entities, the Province or the communities.
This chapter will first provide a brief summary of the hydrogeological characterization of
the aquifer, its state of salinization and causes of saltwater intrusion based on previous
monitoring and modeling works (Giambastiani et al., 2007, Antonellini et al., 2008, Ulazzi et
al., 2008) and work in progress (Mollema et al., 2008). Possible remediation methods that
could counteract saltwater intrusion will be discussed as well as the challenges that scientists
and water management authorities need to face in order to change a historically grown way of
doing things, into sustainable water management that serves many scopes at once over a large
territory.