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Assessing the benefits of groundwater protection levels: a case in the Upper Rhine aquifer, France

IWRA World Water Congress 2008 Montpellier France
1. Water availability, use and management
Author(s): Jean-Daniel Rinaudo
Stéphanie Aulong

BRGM – French Geological Survey – Environmental Economics Unit, 1039 rue de Pinville, 34000 Montpellier, France. Tel : +33 467 157 985. jd.rinaudo@brgm.fr

Keyword(s): Contingent valuation, willingness to pay, groundwater, quality thresholds
Article: Poster:


Following the Water Framework Directive (2000/60/EC), European Member States are initiating water protection programmes aiming at restoring good ecological status for all water bodies before 2015. Whilst the directive defines environmental objectives for surface water bodies, it has not been considered appropriate to define new groundwater quality standards which would be applied uniformly to all groundwater bodies across Europe. Instead, the legislator preferred to leave up to Member States to determine concentration thresholds for major pollutants. The French part of the Upper Rhine aquifer fulfils respectively 50% and 80% of industrial and drinking water needs. This aquifer is increasingly affected by industrial pollution in particular with chlorinated solvents. We use a contingent valuation survey to assess population willingness to pay (WTP) for restoring two alternative levels of groundwater quality consisting first in restoring groundwater quality up to drinking water standards and second in restoring natural quality. The questionnaire was sent out by mail to 5000 households selected in rural localities (2000), urban areas (2000) and in municipalities located outside the aquifer and using other water resources (1000). It includes questions on the perception of groundwater pollution problem, knowledge of CS and of water bill, a description of current situation; people were then asked their ability and WTP for both scenarii and to explain their response; the questionnaire ends with socioeconomic questions. The response rate (13.4%) is conforming to similar methods. 62% of the respondents accept to contribute to scenario 1: mean WTP is 42€/households. For scenario 2, 54% of the respondents are willing to contribute and mean WTP is 76€/household. Unexpectedly and in both scenarii, the average WTP of respondents living above with aquifer is not higher than WTP of respondents living outside the aquifer. A major finding is the relatively high protest rate close to 53% for the scenario 1 (17% for the second). This attitude is mainly due to the fact that the scenario is perceived as inconsistent with the polluter pays principle. The ability to pay is analysed through linear Logit model and shows that the main significant variables are the realism of the described scenarios, the number of children in the household, the income and the number of known polluting substances. Two models were tested to explain stated WTP amounts. Unexpectedly, the knowledge of the water bill has a negative impact on the WTP amount. Significant variables are quite different from the Logit model: income, knowledge of water bill, concern about groundwater pollution, practice of water activities (leisure), and use and non-use values of groundwater advocated as motivations to pay. The predicted WTP range between 19 and 29€ per household for scenario 1 and between 54 and 79€ per household for scenario 2 according to the regression model used and the inclusion of protest answers or not.. Finally, the total benefits of the aquifer are estimated after a sample bias correction. The total benefits of groundwater protection is estimated at 29 million € for the scenario 1 and 46.5 million € for scenario 2.

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