The Serchio River Basin is defined as a basin of national interest according to Italian law and has been identified as ‘river basin district’ for implementation of EU’s Water Framework Directive. The unique combination of challenges that are present include extreme drought and flooding, seismic risk as well as water pollution.
The “Autorita’ di Bacino Distrettuale dell’Appennino Settentrionale” (ADBS) is the authority that leads efforts to address these risks in a portion of the river basin, Massaciuccoli Lake, through the design and implementation of a diversion channel which has been funded by the Ministry of the Environment and the Protection of the Territory and the Sea. The water supply through the diversion channel will be coupled with the implementation of several NBS techniques to mitigate the effects of climate change and at the same time increase biodiversity and improve water quality.
Photos from the Serchio River Basin, Italy. On left, Lake Massaciuccoli area during the flood of December 2009. On right, Lake Massaciuccoli area during the drought of July 2017.
A number of NBS measures have been proposed to mitigate the hydro-meteorological risk in the area.
The area for NBS interventions by Lake Massaciuccoli. Buffer strips are being implemented in ‘Case A’ and ‘Case B’, whereas the retention and sedimentation dam is planned at the location of Case C’. ‘Case D’ denotes a suggested learning platform for NBS on the local and regional level. (Illustration by ADBS)
Specific suggestions include restoration and re-vegetation efforts:
- the inclusion of buffer strips along two main areas of the secondary canal system (case A and Case B in figure above), vegetated with plants designed to stabilize the soil and to reduce the runoff of sediments and pollutants from the agricultural fields to the canals and downstream to the lake.
Sketch and example of the vegetated buffer strips being implemented along irrigation canals.
- The construction of a sediment retention basin (case C in figure of Lake Massaciuccoli), downstream the canal system, aimed to collect and deposit the sediments that still entered the system. Water plants in the basin will further clean the water, before the pumping system takes it to the lake. The pumps are in place because the whole area was drained from being a swamp to become farmland in the 1930’ies.
Implementation of NBS
The Basin Authority is collaborating with stakeholders (local farmers and other organizations) to implement these NBSs, including the maintenance and monitoring plans, and explore planning strategies with the overall goal to develop an ecosystem-based management approach for hydrogeological risk reduction in the whole area of the Massaciuccoli Lake.
The implementation of the vegetated buffer strips is being carried out by the local farmers, who have reshaped the canals and seeded typical native species to function as buffers against runoff of nutrients, as well as chemicals (fertilizers, pesticides) used during agriculture practice.
Ground preparation along one of the canals, before the seeding (left picture) and buffer strip area with growing grass on both sides of the canal (pictures from ADBS, February 2021).
The sedimentation basin has been created and a mixture of phragmites australis and thypha latifolia is used as water plants to trap and stop the sediments into the basin.
Pictures from the area where the sedimentation basin is being realized (pictures from ADBS, February 2021).
Canal management by Lake Massaciuccoli
A final proposed NBS intervention for the area around Lake Massaciuccoli is to modify the shape (cross-profile) of two important canals, to increase their hydraulic capacity, and thereby increase their flood mitigating capacity. This measure is the last in the total set of measures to both reduce runoff of sediments and pollutants, but which also serve as important flood mitigation measures.
Because these measures are closely connected and forms a system of mitigation measures, the expected co-benefits of this last NBS measure are the same as for the other, and in fact further serve to enhance the co-benefits when all the interventions are working together to reduce problems around the lake.
The proposal is under evaluation by the PHUSICOS Steering Committee. Implementation is planned to take place in the fall of 2021 or in the spring of 2022.
Left: Map showing all NBS interventions south-east of Lake Massaciuccoli.
Right: Figure showing the planned modification of the canals’ cross section.
Potential for upscaling
The potential for upscaling is high in this area and it is hoped that this will foster the implementation of a territorial management strategy for overcoming the challenging issues associated with drought and for mitigating floods and landslide risks.
Over the next years, ADBS will focus its attention to upscaling these solutions as best-practices to other regions in Italy.
In addition to the main goal of reducing flood risk and transport of sediments and pollutants, the measures have a range of co-benefits, such as:
- A cleaner lake
- Well-being for inhabitants and for tourists, as this is an important tourist area.
- Enhancing biodiversity by avoiding agriculture all the way up to the channels.
- Carbon storage with increased vegetation, which is not harvested.
- Boosting local green economy.
- Creating increased cooperation, enthusiasm, and sense of ‘ownership’ among stakeholders (farmers).
Contact person: Nicola del Seppia, firstname.lastname@example.org