Brambati, et al.(2003) deal with the geological setting, history and subsidence of the Venetian Plain. Major attention is paid to the Pleistocene-Holocene stratigraphic sequence in the Lagoon of Venice, in relation to its origin that dates back to 6 to 7 kyr BP. Geological land subsidence has played an important role in the origin and the evolution of the lagoon, and anthropogenic subsidence, which has recently assumed a major importance for the Venetian environment. Considering also the sea level rise, 23 cm loss in land elevation has occurred in the last century, is leading to increased flooding events and environmental problems that require protective works. Subsidence induced by groundwater withdrawals became a problem with the industrial boom after the 2nd World War.
This process has been studied in detail, the cause-and-effect relationship quantified, and a 2-D and a 3-D simulation models were developed. The aquifer-aquitard system is located in the upper 350 m of the 1000 m thick unconsolidated Quaternary formation. Groundwater withdrawal, which progressively led to a noticeable decline of aquifer pressure, began in the 1930s reaching a peak between 1950 to 1970 together with the subsidence it caused (the maximum rate of 17 mm/yr was recorded between 1968 to 69 over the industrial zone). After this critical 20-year phase, a general improvement occurred quickly because of the closure of artesian wells and the diversification of water supply.
The 1973 levelling clearly showed a reversed trend of subsidence and a slight but significant rebound was measured in 1975, with a maximum of 2 cm in the historical city, as predicted by simulation models (i.e. Gambolati et al., 1974). The 1993 and 2000 regional surveys confirmed the arrest of anthropogenic subsidence as a widespread phenomenon.
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