Optimal operating rules under climate change combining agricultural and environmental goals with multiobjective programming in the Serpis River Basin (Spain)

19:00 Tuesday 28 May




Francisco Martinez-Capel (Spain) 1; Manuel Pulido-Velazquez (Spain) 1; Hector Macian-Sorribes (Spain) 1; Rafael Muñoz-Mas (Spain) 2; João Vieira (Portugal) 3; Cristina Barea-Sanchez (Spain) 1; Martin Ruiz-Rodriguez (Spain) 4

1 - Universitat Politècnica de València (UPV); 2 - Universitat de Girona; 3 - ITECONS - Universidade de Coimbra; 4 - Suez

The objective of the research presented is the update of the operating rules and environmental flow regimes of the Serpis river (Eastern Spain) to minimise the impact of climate and land use change in its agricultural areas and native fish species while reducing as much as possible the competition between native and invasive fish species.

To achieve this objective, fish habitat modelling was combined with hydroeconomic modelling and multiobjective programming. The case study Serpis River is regulated by the Beniarrés reservoir. Fish habitat modelling was developed by coupling multivariate habitat suitability models with hydraulic simulations to estimate the available habitat under different flow regimes. The consideration of native and invasive species enabled the possibility of defining environmental flow regimes that favour native species while reducing their competition with invasive species. Hydroeconomic water management estimate the impact of climate change and environmental flow regime updating on economic benefits of irrigated agriculture.

Climate change hydrological scenarios were defined using the last IPCC AR5 climate change scenarios, in combination with hydrological models set up for the Serpis River Basin. Land use change scenarios in the irrigated agriculture were assessed using trend analysis of current agricultural areas and interviews with the Serpis River Basin farmers. A multiobjective optimization was performed to define a Pareto front indicating optimal trade-offs between the economic cost of climate and land use change for agriculture, the suitable habitat for native species and the competition between native and invasive species, using the BORG-MOEA (Multi-Objective Evolutionary Algorithm).

The analysis of all climate and land use change scenarios for the Serpis River pointed out towards a decrease of 400 m2 of native habitat area and a benefit loss between 15 and 20%. The BORG-MOEA revealed for all the scenarios that climate and land use change impacts can be lowered in 25% of the total impact in all the objectives at once (no trade-offs) by improving the operation of Beniarrés. Nevertheless, improving of a single objective more than this threshold implies an opportunity cost on the others. It can be conclude that improving the operation of the Serpis has significant benefits for both agriculture and fish habitat. For most of this improvement no trade-offs were detected, although focusing in just one objective may have a significant opportunity cost on the others.

The European Research Area for Climate Services programme (ER4CS) supports this study under the INNOVA project (grant agreement: 690462).