 |
| Titel |
Assessing forest influences on torrential hazards and risks: IRSTEA mission within the European H2020 project NAIAD |
| VerfasserIn |
Guillaume Piton, Jean Marc Tacnet, Frédéric Berger, Corinne Curt, Thomas Curt, Patrick Arnaud |
| Konferenz |
EGU General Assembly 2017
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250147935
|
| Publikation (Nr.) |
 EGU/EGU2017-12155.pdf |
|
|
|
|
|
| Zusammenfassung |
| NAIAD (NAture Insurance value: Assessment and Demonstration) is a H2020 European
project gathering 23 partners interested in ecosystems services related to water. The project
more specifically links nature services to the assurance world and aims to operationalise
“Natural Assurance Schemes”, defined as a range of schemes to internalise the value of
ecosystems services, e.g., the buffering role of river systems against water risks,
in insurance policies. It is based on an assessment methodology that includes the
physical, socio-cultural and valuation aspects of ecosystems services in relation to
water, adapted to the institutional frame to align economic incentives and financial
flows.
Within the NAIAD projet, IRSTEA will more specifically try to highlight the role of
mountain forests in torrential flood hazards and risks. The forest eventually acts
on hydrology by buffering part of the rainwater. Vegetation has also a key role
in soil conservation by curtailing primary sediment production in the hillslopes.
Conversely, woody debris dramatically aggravate hazards by clogging bridges and key
protections structures as open check dams. Finally this dual role may change in time due
to the forest vulnerability to climatic, biologic or physical changes, e.g. after a
wildfire.
The first project step will be an extensive literature review on all these effects. Secondly
indicators describing the torrential systems will be proposed and link to variably pronounced
influence of forest. In a third time, case studies will be undertaken. The dramatic flood that
occur in the region of Nice in summer 2015 (20 fatalities) will probably be used as a
benchmark test. Several scenarios of alternative forest and river managements under varying
climate forcing will be tested later. Complete torrential risk assessment studies will
be performed on several sites within this project, with and without the forest
influences in order to highlight its role. Numerous check dams have been built in
headwaters to facilitate reforestation in the past, their influence on the torrential flood
triggering (e.g., sediment supply) and transfer (e.g., debris flow propagation) will be
assessed. The effectiveness of protections structures as debris basins and woody debris
traps will be studied. They are supposed to be key solutions to the drawbacks of
woody debris jams resulting from forest standing in catchments, other effects on
hydrology and sediment production being quite positive. The issue of uncertainty and its
propagation along the whole chain of analysis will be subject to a special effort in our
work.
The NAIAD project just beginning in 2017, we propose to present the research steps and
data treatment chains that are planned to be used along the project. More results and the case
studies being under progress. |
|
|
|
|
|
|