allow fish circulation despite deviation in the marsh). Calculation of ecological gains using HEA gave us 0.079 DSAYs and 0.158 DSAYs for performances of 2 and 4 kg per day per hectare respectively. Objective for Metrics Determination of baseline DSAYs valuation Nitrate mitigation Purification performances of 2 kg per day Objective of 50 tons per year 0,079 Nitrate mitigation Purification performances of 4 kg per day Objective of 50 tons per year 0,158 Table 5 - Application of HEA to measure the environmental gains in the Kervigen marsh The strategy of restoration fixes an objective of reduction of 50 tons of nitrate per year, this can be considered as a deficit of ecological services: if nothing is done 100% of services will be lost, corresponding to 18.41 DSAYs between 2012 and 2037. Considering the gains associated to the Kervigen marsh rehabilitation we can propose discussion on the different strategies for restoration of marshes (Table 4). Using HEA we can determine the need of restoration to reach 50 tons of nitrate reduction. We can see that changing the time limit for the objective will change the total surface of project, because of the application of a discount rate that gives preference for services produced in 2012, rather than later. Strategy for marsh restoration Surface to restore per year Total surface to restore Objective in 2012 234 ha 234 ha Objective in 2015 64 ha 254 ha Objective in 2020 33 ha 294 ha Table 6 - Dimensioning restoration plan according to different strategy scenario for a selected performance of 2 kg.day-1.ha-1 Environmental measures of Port 2000 The Seine estuary refers to the part of the river that is subject to tidal influence. It is a densely populated region and home to a variety of economic activities. The estuary is characterized by the presence of a high biological diversity (birds, fish, etc.) and included in the Natura 2000 network. It is also protected by the existence of the Nature Reserve of the Seine Estuary. Because of the construction of Port 2000, the Le Havre harbor had to set up two types of environmental measures to offset impacts on local biodiversity: compensatory measures and accompanying measures. Compensatory measures that focused on the creation of a resting place on dune - a resting area of 45 ha consisting of a basin subject to tidal influence and a large dry area - and an islet resting place - an islet of 5 hectares at low tide which is reduced to 1.5 ha and three smaller
allow fish circulation despite deviation in the marsh). Calculation of ecological gains using HEA gave us 0.079 DSAYs and 0.158 DSAYs for performances of 2 and 4 kg per day per hectare respectively. Objective for valuation Metrics Determination of baseline DSAYs Nitrate mitigation Purification performances of 2 kg per day Objective of 50 tons per year 0,079 Nitrate mitigation Purification performances of 4 kg per day Objective of 50 tons per year 0,158 Table 5 - Application of HEA to measure the environmental gains in the Kervigen marsh The strategy of restoration fixes an objective of reduction of 50 tons of nitrate per year, this can be considered as a deficit of ecological services: if nothing is done 100% of services will be lost, corresponding to 18.41 DSAYs between 2012 and 2037. Considering the gains associated to the Kervigen marsh rehabilitation we can propose discussion on the different strategies for restoration of marshes (Table 4). Using HEA we can determine the need of restoration to reach 50 tons of nitrate reduction. We can see that changing the time limit for the objective will change the total surface of project, because of the application of a discount rate that gives preference for services produced in 2012, rather than later. Strategy for marsh restoration Surface to restore per year Total surface to restore Objective in 2012 234 ha 234 ha Objective in 2015 64 ha 254 ha Objective in 2020 33 ha 294 ha Table 6 - Dimensioning restoration plan according to different strategy scenario for a selected performance of 2 kg.day-1.ha-1 Environmental measures of Port 2000 The Seine estuary refers to the part of the river that is subject to tidal influence. It is a densely populated region and home to a variety of economic activities. The estuary is characterized by the presence of a high biological diversity (birds, fish, etc.) and included in the Natura 2000 network. It is also protected by the existence of the Nature Reserve of the Seine Estuary. Because of the construction of Port 2000, the Le Havre harbor had to set up two types of environmental measures to offset impacts on local biodiversity: compensatory measures and accompanying measures. Compensatory measures that focused on the creation of a resting place on dune - a resting area of 45 ha consisting of a basin subject to tidal influence and a large dry area - and an islet resting place - an islet of 5 hectares at low tide which is reduced to 1.5 ha and three smaller