Impact of climate change on the hydrology of shallow Lake Trasimeno (Umbria, Italy): History, forecasting and management

Abstract

Lake Trasimeno is the largest lake of the Italian Peninsula. Because of the small extent of its watershed, meteorological conditions have caused dramatic floods and droughts over the centuries. Although numerous attempts have been made to regulate the lake level since Etruscan or Roman times, the problems related to water level changes remain unsolved, and the recently adaptive management strategies seem to be ineffective in the current climatic conditions. This study evaluates past and future management scenarios with the aim of identifying effective strategies to limit the lake level fluctuations. A lumped hydrological model, which incorporates climate forcing and water regulation policies adopted currently and in the past, is calibrated and validated using a fifty-year data series. Future scenarios (present–2090) of water level change are simulated on the basis of IPCC (Intergovernmental Panel on Climate Change) regional projections for precipitation and temperature. Possible mitigation measures, such as those involving the enlargement of the catchment basin, the water diversion from nearby dams and the adoption of more restrictive rules on abstractions are also considered. The model indicates that critical prospects emerge if the intermediate or the maximum rates of change estimated by global climate models are assumed. Under these circumstances, currently feasible mitigation measures seem effective in preventing severe water shortage in the next decades, but ineffective in preventing the drainage of the lake in the second half of the century. We recommend that plans for water resource management should be put in place as a matter of urgency to ensure the conservation of the hydrologically vulnerable Lake Trasimeno.

Plankton dynamics across the freshwater, transitional and marine research sites of the LTER-Italy Network. Patterns, fluctuations, drivers

“…Hypotheses about the causes of these changes deal with direct and indirect effects of meteoclimatic changes. From 1991 to 2012, Lake Trasimeno experienced a drought period (Ludovisi et al, 2013), which rapidly increased salt concentration (Ludovisi and Gaino, 2010), affecting many phytoplankton species. On the other hand, an increase in temperature observed in the same period, concomitant to the reduction in the water level, has likely favored summer blooms of filamentous cyanobacteria.…”

Nutritional composition of raw and fried big-scale sand smelt (Atherina boyeri) from trasimeno lake

“…In the Lake Trasimeno, this species represented almost 27% of the total catch, when fish withdrawal reached 240 tons a year. In recent years, the quantity of fish has decreased, probably due to the lowering of the hydrometric levels of the lake (Ludovisi et al 2013).…”

Integrated Water Resources Management in a Lake System: A Case Study in Central Italy

“…Previous studies provide a framework for future and more focused investigation [3,42,43]. In this section these assessments were conducted on the basis of climate change scenarios derived from different general circulation models (GCMs).…”

“…For this reason it is important to project an integrated water resources management plan for the Upper Tiber River Basin, where two artificial reservoirs have been projected and partly built: the Montedoglio reservoir on the Tiber River and the Casanova reservoir on the Chiascio River ( Figure 2). The storage capacities of the Montedoglio and Casanova reservoirs are, respectively, 142 and 185 Mm 3 . They are multi-purpose artificial basins and their long-term management may involve the area of Lake The storage capacities of the Montedoglio and Casanova reservoirs are, respectively, 142 and 185 Mm 3 .…”

“…Lake Trasimeno is continuously subject to level fluctuations, but nowadays climate change [3] and water quality [4] need to be taken into account in order to manage the level of the lake in the next years. For this reason it is important to project an integrated water resources management plan for the Upper Tiber River Basin, where two artificial reservoirs have been projected and partly built: the Montedoglio reservoir on the Tiber River and the Casanova reservoir on the Chiascio River ( Figure 2).…”