Modelling sea level rise impacts and the management options for rice production: the Ebro Delta as an example

Identifier:  TDX:3326

Handle: https://hdl.handle.net/20.500.11797/TDX3326

Authors:  Genua Olmedo, Ana

Abstract:
Coastal areas have to cope with increasing risks related to SLR. The Ebro Delta is a valuable ecosystem representative of the vulnerability of coastal areas to SLR. Rice production is the main economic activity, occupying ca. 65 % of the total surface is sensitive to SLR, and the increase in soil salinity, the most limiting factor. Thus, it is necessary to analyse the impacts of SLR, i.e. flooding and soil salinization, and to develop appropriate adaptation measures. We built spatial models (1 × 1 m) in areas prone to be flooded, sediment loss, soil salinity, and rice production loss. We coupled data from GIS with GLMz and models were run under different scenarios predicted by IPCC (AR5) up to 2100. We also evaluated the feasibility of an innovative nature-based adaptation measure consisting in reintroducing sediments trapped in basin reservoirs into the delta plain. Elevation (inversely related) was the most important variable in explaining soil salinity, thus, models predicted a decrease in normalized Rice Production Index following the delta elevation gradient. Subjected to the scenario considered, the models predict a RPI reduction from 62.1 % in 2010 to 54.6 % by 2100 in the most conservative scenario (SLR = 0.53 m); and to 33.8 % in the worst considered scenario (SLR = 1.8 m), with a decrease of profit up to 300 € per hectare. For the same scenarios, the flooded rice fields’ area ranged 36-90 %, and the sediment loss 122-418 million tonnes. The nature-based adaptation measure proposed had a positive effect on rice production, and it can be considered as an innovative management option for maintaining the Ebro Delta ecosystem services although SLR. Our models can be applied to other deltaic areas worldwide, helping farmers and stakeholders to identify vulnerable areas to SLR impacts and to develop management plans.