Economic analysis applied to groundwater degradation due to contaminated sites Public perception and willingness to pay for the RWM073 groundwater quality improvement 11 ,/ Deliverable 5.5 Final report
BRGM/RP-59800-FR April, 2011
This report is part of the project Flux-based Risk Assessment of the impact of Contaminants on Water resources and ECOsystems (FRAC-WECO) funded by the Belgian Science Policy, Contract n°SD/TE/02A
C. Hérivaux
Cîosciencelora sustainable Earth
3 5000 00081133 0
BELGIAN SCIENCE POLICY 1
CONTRACT NB SD/TE/02A FRAC-WECO Flux-based Risk Assessment of the impacts of Contaminants on Water resources and ECOsystems Programme : La Science pour un Développement Durable Programma : Wetenshap voor een Duurzame Ontwikkeling
Deliverable D5.5
Economic analysis applied to groundwater degradation due to contaminated sites
Public perception and willingness to pay for the RWM073 groundwater quality improvement
Responsible Cécile Hérivaux (BRGM)
Authors C.Hérivaux
Corresponding author c.herivaux^brgm.fr Public perception and willingness to pay for the RVVM073 groundwater quality improvement
Acknowledgements
Implementing a contingent valuation is a rigorous and iterative teamwork, not only for the questionnaire design phase but also for the implementation of the survey by itself and the econometric analysis of the results. I would like to warmly thank the following people for their precious help at different steps of the work:
Cristina Popescu, Francis Delloye (DGARNE), Fanny Van Wittenberge (Protectis SA), Delphine Fontenoy (Espace Environnement), Laura Maton, Jean-Daniel Rinaudo, Stéphanie Aulong (BRGM) for their contribution to the design of the questionnaire ; Xavier Sohet (Espace Environnement), Serge Brouyère, Pierre Jamin (ULg) for their contribution to the practical organizafion of the survey; Flore Andrien, Pierre Briers, Florent Dufrane, Thomas Hermans, Louise Marchand, Nathan Marchand (students), Laura Maton, Jaan-Daniel Rinaudo (BRGM), Xavier Sohet, Jean-François Bayot (Espace Environnement) for their active participation to the test and/ or the survey. And of course the 531 people who accepted to give us a part of their time for answering to the questionnaire.
In bibliography, this report should be cited as follows:
C.Hérivaux (2011), Economic analysis applied to groundwater degradation due to contaminated sites: Public perception and willingness to pay for the RWM073 groundwater quality improvement. Deliverable D5.5 ofthe FRAC-WECO project. BRGM-RP-59800-FR.
© BRGM, 201 1 . No part of this document may be reproduced without the prior pemiission of BRGM
BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement
Synthesis
This report presents an economic valuation of benefits expected from groundwater quality improvement, by using the contingent valuation approach.
The case study is a groundwater body located in the industrial basin of Liège, in the Meuse Valley (Walloon Region). This groundwater body covers a length of about 30km and constitutes the most polluted part of the Meuse alluvial aquifer. Chemical pollutants emitted by urban and industrial activities have strongly degraded the groundwater quality. While pollution exerted by current activities is expected to be reduced in the coming years by the evolution of regulation and by the strengthening of controls, a high density of brownfields still remain in place, with historic pollution likely to leach into groundwater. Due to its poor quality level, particularly around brownfields, groundwater use should be avoided, excepted for some industrial uses. As groundwater discharges into the Meuse it may also contribute to a degradation of the Meuse quality. If nothing is undertaken to manage this historic pollution, groundwater will remain polluted for decades.
By implementing a contingent valuation survey, our aim was (1) to analyze the public knowledge of the groundwater body and its perception of the quality management problem and (2) to assess if people would attach an economic value to an improvement of this groundwater quality and how much. Given that the groundwater body is located in a heavily industrialized area, with a high unemployment rate and with industrial activities being historically both the main groundwater polluters and users, our assumptions prior to the survey were (1) that people would have a low level of knowledge of the good to be valued, (2) that few people would be willing to contribute to a groundwater quality improvement scenario and (3) that proposed individual willingness to pay (WTP) amount would be rather low. Individual WTP amounts were expected to be related to several factors: the geographic location of the respondent, to his groundwater usa, to the level of likelihood granted to the information provided by the questionnaire, to tha importance granted to the groundwater quality improvement, to the main types of benefits considered, to his mobility, to the intensity of encountered environmental problems and to individual socio-economic characteristics.
The survey was designed and implemented from May to September 2010. The questionnaire proposes a scenario of groundwater quality improvement by 15 years if actions are undertaken now. Expected benefits can be related to option, indirect use and non-use values. 531 face to face interviews were completed. The representativeness of the interviewees is quite good concerning the age distribution, gender, employment, income, household size and geographic location.
As expected, the proportion of direct groundwater users is very low (1.5%). Results also confirm that the good to be valued is poorly known. The knowledge of the existence of the Meuse alluvial aquifer is quite low with only 20% of tha respondents aware of it. The existence of brownfields in the study area is batter known with 63% of tha respondents being aware of it. Less than a quarter of the respondents had already heard about the groundwater degradation problem (20%) or consider themselves well informed about it (4%). One third of the respondents knew the origin of their tap water.
BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement
However 98% of the respondents consider it is important to improve the quality of the groundwater body and tha majority (58%) estimates that reaching the proposed benefits by 2015 is realistic. Two third of them would be willing to contribute financially to this improvement by an increase in thair water bill. Tha main motivation for paying is relatad to future generations and to tha Meuse quality improvement. Tha average WTP is 46.9 whan only positive WTP are considared. The average WTP is 40.1 when true zeros are included.
An econometric analysis is carried out to identify which factors influence significantly the willingnass to contributa and tha WTP amounts. Three models are selected: a logistic regression model (to explain the willingnass to contribute), an ordinary least square regression modal (to explain the positive WTP amounts) and a Tobit regression model (to explain positive or true zeros WTP amounts).
Results show that:
Not surprisingly, tha more respondents consider tha improvement scenario as realistic and important to ba implamantad, the mora they are willing to contribute for this scenario.
Men and people with higher income are mora willing to contribute, and propose higher WTP amounts. People with higher aducafion degree offer higher WTP amounts. People living above the aquifer are more likely to contribute. However positive WTP are not limited to these people. Households living outside the boundaries of the aquifer may also have positive WTP, decreasing with the distance to the Meuse. Evan if the proportion of groundwater users is close to zero, the observed percentage of people likely to contribute and observed WTP amounts are far from being negligible. In this case study, positive WTP are thus not limited to groundwater users and the main reason for contributing is not related to a potential future use ofthe resource. Respondents feeling affected by a high number of environmental problems are more willing to contributa, with higher WTP amounts. Respondents' level of information on the groundwater quality problem does not have any significant affect on thair willingness to contribute nor on their WTP amount.
Tha contingent valuation results ara than used to assess the total benefits expected from the proposed scenario of groundwater quality improvement. These total benefits can be estimated by aggregating obsen/ed individuals' benefits to tha population that may benefit from the groundwater quality improvement. Annual aggregate benefits expected from an improvement of the quality of the groundwater body ara estimated at 7.8 million euros when considering the sampling area. They could reach 8.8 million euros whan considering tha extended geographic area delineated by tha use of the distance decay function. Total aggregate benefits would thus reach between 63 and 71 million euros, depending on the considered population of banaficiaries.
BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement
Glossary
WFD Water Framework Directive
WTP Willingness to Pay
BRGM-RP-59800-FR - Final report
Public perception and willingness to pay for the RWM073 groundwater quality improvement
Contents
1. Introduction, context and objectives 13
2. Description of the case study 15
3. Set up of the survey 19
3.1. QUESTIONNAIRE DESIGN 19
3.2. DEFINING THE SCENARIO 22
3.3. TEST OF THE QUESTIONNAIRE 23
3.4. PRACTICAL ORGANIZATION OF THE SURVEY 23
4. Valuation results: descriptive statistics 25
4.1. RESPONDENT CHARACTERISTICS AND SAMPLE REPRESENTATIVENESS 25
4.2. PUBLIC KNOWLEDGE AND PERCEPTION OF THE MEUSE ALLUVIAL GROUNDWATER BODY 30
4.3. PUBLIC PERCEPTION OF THE GROUNDWATER QUALITY IMPROVEMENT SCENARIO 33
5. Valuation results: econometric analysis 37
5.1. GENERAL ASSUMPTIONS 37
5.2. LIST OF EXPLANATORY VARIABLES 38
5.3. LOGISTIC REGRESSION OF WILLINGNESS TO PAY 42
5.4. ORDINARY LEAST SQUARE REGRESSION OF WILLINGNESS TO PAY (WTP>0)..43
5.5. TOBIT REGRESSION OF WILLINGNESS TO PAY (WTP>0) 45
5.6. PREDICTED VERSUS OBSERVED VALUES 46
5.7. SYNTHESIS AND DISCUSSION 46
6. Benefits expected from an improvement of the groundwater body quality 51
7. Conclusion 57
8. References 57
BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement
List of illustrations
Figure 1. Proposed methodological steps of WP5 13
Figure 2. Location ofthe part ofthe aquifer under study (in light blue, schematic representation of the main water resources used for tap water production in the Liege area) 15
Figure 3. Origin of tap water by communa (in blue: communes supplied partly by tha Meuse alluvial aquifer, in yellow: communes supplied by alternative resources) 16
Figure 4. Scheme describing the functioning of an alluvial aquifer 19
Figure 5. Example of map combining Google Earth views and aquifer boundaries 20
Figure 6. Sampling area and selected communes 24
Figure 7. Comparison between respondents and population age distribufion 26
Figure 8. Net monthly income distribufion per household 27
Figure 9. Distribution of interviews by commune 28
Figure 10. Number of questionnaires completed by communa 28
Figure 11. Part of life spent in the study area and likelihood to move out 29
Figure 12. Number of respondents using water from wells or rainwater harvesting systems 30
Figure 13. Respondents' prior knowledge of tha situafion 31
Figure 14. Respondents' perception of the groundwater degradation problem 32
Figure 15. Likelihood ofthe reference scenario 33
Figure 16. Realism of tha improvement scenario 33
Figure 17. Proportion of different types of answers 34
Figure 18. Distribution of positive WTP amounts 36
Figure 19. Mean positiva WTP observad by communa 36
Figure 20. WTP amount as a funcfion of tha distance to tha Mausa 49
Figure 21. WTP - distance decay function (from the Tobit regression) 53
Figure 22. Population of banaficiaries : delineation of area 1 and area 2 54
Table 1. Benefits expected from the improvement scenario by type of groundwater use 23
Table 2. General characteristics of respondents 25
Table 3. Comparison between respondents and population employment status 26
Table 4. General characteristics of respondents 30
Table 5. Groundwater use likely to present a risk 32
Table 6. Motivations for paying 34
10 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement
Table 7. Motivafions for refusing to pay 35
Table 8. Expected effects of the main studied factors 38
Table 9. List of selected potenfial explanatory variables and short descripfion 41
Tabla 10. results of tha binomial logisfic regression explaining tha willingnass to contribute 42
Table 11. Results ofthe OLS regression explaining WTP values 44
Table 12. Results of tha Tobit regression explaining WTP values 45
Table 13. Observed vs predicted WTP values 46
Table 14. Synthesis ofthe significant variables 47
Table 15. Coefficients and mean valuesof significant variables (Tobit regression modal) 52
Table 16. Aggregate benefits asfimatas 55
BRGM-RP-59800-FR - Final report 1 1
Public perception and willingness to pay for the RWM073 groundwater quality improvement
1. Introduction, context and objectives
Following the requirements of the Water Framework Directive, a programme of measures selected on the basis of a cost-effectiveness analysis should be proposed for each water body at risk of not reaching good status. In case of disproportionate costs derogation may be justified on the basis of a cost-benefit analysis. This economic analysis is a challenging task in case of groundwater bodies at risk due to brownfields (historic industrial contamination): remediation measures are expected to be very expensive, time required for remediation may be very long, groundwater resources are generally not used anymore as a resource {making it difficult to anticipate (i) if market benefits could be expected from an improvement of the groundwater quality and (ii) if people would be willing to contribute to this quality improvement). Specific questions raised in WP5 of the FRAC- WECO project are: How much will it cost to improve the quality of a groundwater body currently degraded by brownfields? What is the (and is there a) potential economic value of a groundwater resource currently degraded by brownfields? The proposed methodology of WP5 is structured into six main steps distributed among the two phases of the project (see Figure 1).
D5.1 Typology of damage, selectionof valuation methodsand relevantscale Meetings and literature review I . UJ D5.2 D5.3 Selection of the RWM Assessment of the potential market 073 as a case study. benefits that may arise for the socio-economic economic sectors from an characterisation improvement of the RWM 073 . ¿O quality Meetings and data collection Data collection, survey / D5.4 Assessment of the public Design of prog ram(s)of measures perception and willingness to pay aiming at improving RWM 073 quality for an improvement of RWM 073 w LU and assessment of its (their) costs quality O O Meetings with experts and literature Contingent valuation survey review I __ D5.6
Cost-Benefit analysis of the proposed prog ram(s)of measures I !
Figure 1. Proposed methodological steps of WP5
BRGM-RP-59800-FR - Final report 13 Public perception and willingness to pay for the RWM073 groundwater quality improvement
This report focus on sub-task 5.5: its main objectives are (1) to analyse public perception of a groundwater body currently deteriorated by brownfields, (2) to assess individual benefits that people may obtain from an improvement of its quality, (3) to understand which variables are significant in tha individual values obtained and (4) to propose an assessment of the total benefits that could be expected from an improvement of tha groundwater quality by aggregating individual values. This report presents tha results of a casa study conducted in tha Meuse alluvial valley (Walloon Region) where a contingent valuation survey was implamantad on a part of the Mausa alluvial aquifer (namely the RWM073 groundwater body) between May and September 2010.
The report is structured into five main parts. Chapter 2 proposes a short description of the case study. Chapter 3 presents tha preparation and the implementation of the contingent valuation survey. Tha analysis and discussion of tha results is proposed by Chapter 4 (descriptiva analysis) and Chapter 5 (econometric analysis). The aggregafion of benefits is then conducted in Chapter 6.
14 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement
2. Description of the case study
The RWM073 groundwater body is part of the Meuse alluvial aquifer which extends over 120 km and a maximum width of 2 5 km in the Walloon Region, from the French boundary to Visé, crossing the cities of Namur and Liège (Figure 2). This alluvial aquifer is constituted by a layer of sands and gravels located at low depth under the Meuse and with a thickness ranging from 8 to 15 m.
The RWM073 groundwater body constitutes the most polluted area of the Meuse alluvial aquifer. It is located between Engis and Herstal, over about 30 km. In this area, chemical pollutants emitted by urban and industrial activities have strongly impacted the groundwater quality. While pollution exerted by current activities is expected to be reduced in the coming years by the evolution of regulation and by the strengthening of controls, a high density of brownfields {438 sites/ 100km2) still remain in place, with historic pollution likely to leach to groundwater. If nothing is undertaken to manage this historic pollution, groundwater will remain polluted for decades. As a result, and in the context of the implementation of the Water Framework Directive (WFD), this groundwater body was reported to Europe at risk of not reaching good status by 2015.
• Commune* Lmit» a* I I Lm»» lie ^ I Ffor»*f»
Figure 2. Location of the part of the aquifer under study (in light blue, schematic representation of the main water resources used for tap water production in the Liege area)
BRGM-RP-59800-FR - Final report 15 Public perception and willingness to pay for the RWM073 groundwater quality improvement
Groundwater in this area is mostly used by industrial activities, with 4.5 million cubic meters abstracted each year and by some private domestic wells. Water also discharges into the Meuse. Groundwater is not abstracted for tap water production, other water resources (Figure 2} are used to supply the population of Liège and its surrounding areas (360 000 inhabitants): the Néblon aquifer (approximately 1/3 of the tap water supply), the Hesbaye aquifer (1/3 of the supply) and the Eupen and Gileppe dams (1/3 of the supply). Outside the boundaries of the groundwater body, both upstream and downstream, groundwater is abstracted from the Meuse alluvial aquifer for tap water production (the communes of Oupeye and Amay are for instance partly supplied by this resource, see Figure 3).
1 Coct tftlu «I ffv4fet ^h Cc**>iT»Li«rt (3om Ttju du io£nn4l provi*hl #n p*tri ejn I« fuppo BBuvra!* d* WJ U Figure 3. Origin of tap water by commune (in blue: communes supplied partly by the Meuse alluvial aquifer, in yellow: communes supplied by alternative resources) In accordance with the WFD requirements, benefits should be compared with costs of potential programs of measures in case of disproportionate costs to justify if necessary some objectives derogation. Market benefits expected from an improvement of the groundwater quality were estimated by Hérivaux and Graveline (2009). These are expected to range between 1.3 to 1.8 million euros per year from 2030 (4% discounted values), which is likely to be very low in comparison with the costs required for brownfields remediation1. As market benefits are not expected to constitute the major part of the benefits in this particular context, there is a need to integrate non-market benefits in the valuation. Until now no non-market benefits valuation 1 Average costs required for the remediation of the most polluted sites in the Walloon Region are estimated between 1.25 and 2 million euros per site. If BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement applied to groundwater has been carried out in tha Walloon Region^. This groundwater body thus constitutes an interesting case study to test the advantages and limits of the use of a contingent valuation survey in such a context, which is promoted as tha unique method able to integrate non-use values in the benefits assessment. ^ Bouscasse et al. (2009) have proposed a valuation of the benefits expected from an improvement of the groundwater qualitative and quantitative status in the Walloon Region. However this assessment is based on the transfer aggregation of values obtained by contingent valuation surveys carried out in other European countries. BRGM-RP-59800-FR - Final report 17 Public perception and willingness to pay for the RWM073 groundwater quality improvement 3. Set up of the survey 3.1. QUESTIONNAIRE DESIGN The contingent valuation survey was designed from May 2010 and was implemented in September 2010. The questionnaire is structured into four main sections, with a total of 33 questions: • Section 1 This section presents the part of the aquifer under study. The information part consists in a short text (Text 1 ) describing the functioning of an alluvial aquifer and the location of the part under study of the Meuse alluvial aquifer. The text is completed by a scheme describing the functioning of an alluvial aquifer (Figure 4) and two maps showing the geographic extent of the case study area (Figure 2 and Figure 3). It is followed by a series of questions aiming at assessing respondent's knowledge and perception of groundwater. PLUIE Infiltration dans 8-15m la napp« Nappe alluviale Captages pour différents usages (eau potable, industries) 600-2500m Figure 4. Scheme describing the functioning of an alluvial aquifer BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement Text 1 : the Meuse alluvial aquifer An important groundwater reserve is located in the Meuse alluvial Valley: the Meuse alluvial aquifer. This is constituted by a layer of sands and gravels at low depth, with a thickness ranging between 8 and 1 5 meters, with water filling in the voids between sands and gravels. This groundwater comes from the infiltration of rainwater and water restrained in the surrounding ground. This water may then be abstracted for different types of use and discharges into the Meuse. In the Walloon Region, the Meuse alluvial aquifer covers a length of about 120 km, with a maximum width of 2.5 km, from Givet to Visé, crossing the cities of Namur and Liège. This questionnaire focus on a 30 km long part of the Meuse alluvial aquifer which is located between Engis and Herstal. Respondents are asked if they live above the aquifer under study. A set of maps (A4 paper) combining Google Earth views and aquifer boundaries are provided to respondents to answer this question {Figure 5). A short text {Text 2) completed by the Figure 3 also explains the origin of tap water city by city. Figure 5. Example of map combining Google Earth views and aquifer boundaries 20 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement Text 2 In this part of the aquifer, between Engis and Herstal, the groundv^ater is mainly used by industrial activities , by some households (private wells in the gardens) and discharges into the Meuse. In this sector, tap water does not come from this aquifer, other water resources are used to supply the population of Liège and surrounding areas: the Néblon aquifer, the Hesbaye aquifer, the Eupen and Gileppe dams. Outside the boundaries of the sector under study, tap water comes partly from the Meuse alluvial aquifer (this is the case for instance of Oupeye and Amay). Section 2 This section summarizes the groundwater quality problem today and in the future if no action is undertaken. A text (Text 3) explains that tha groundwater quality is currently degradad by urban and industrial pollution from Engis to Herstal. Tha issue of brownfields and polluting pressures they exert on groundwater is described. Impacts of groundwater pollution on the currant uses of the resources are also presented. Respondents are asked about their knowledge of this situation. A specific question is added to understand if respondents agree and trust tha information wa provided to them (soma of them may find it exaggerated, while others may think we underestimate tha extent of the problem for instance). Text 3: Today this sector of the aquifer is not in a good state The groundwater quality is very degraded between Engis and Herstal by urban and industrial pollution emitted by historic and current activities. By 15 years, the evolution of regulation (stricter discharge norms) and the strengthening of controls will allow to reduce the pollution due to current activities. However, a high number of plants, landfills and industrial sites, abandoned sometimes since decades, still remain in place. These urban and industrial brownfields have left behind historic pollution which always end by leaching into groundwater after infiltration into the soil. These sites are considered as orphan sites since people responsible for the pollution do not exist anymore. In this part of the aquifer, and particulariy around brownfields, water is so polluted that its use should be avoided (including for gardening) excepted for some industrial uses. This is why tap water of Liège and surrounding areas do not come anymore from this aquifer, unlike the communes which are located outside the sector under study. In addition, as groundwater discharges into the Meuse, it may contribute to a degradation of the Meuse quality. If nothing is undertaken to manage these historic pollutions, the groundwater quality wiii remain degraded for decades. Section 3 This section presents a scenario of groundwater quality improvement (Text 4). Proposed measures and expected impacts on groundwater quality and groundwater uses are listed. BRGM-RP-59800-FR - Final report 21 Public perception and willingness to pay for the RWM073 groundwater quality improvement Respondents are askad if they attach importance to the groundwater quality improvement and if they find tha scenario realistic. They ara then asked if they would ba willing to contribute financially (each year during ten years) for such a scenario through an increase of the water bill. Those who agree are askad to specify an amount in euros par year (for the household). Respondents are than askad to explains their motivations for accepting of refusing to contribute. Text 4: Improve the quality ofthe Meuse alluvial aquifer Taking into account the current urbanisation and the existence of industrial activities on the alluvial aquifer, it is unrealistic to believe that the groundwater could retrieve its natural quality level. Nevertheless, an improvement of ¡ts quality is possible. If we act today, a quality improvement could be obtained by 15 years. For this purpose it is proposed to (a) eliminate all historic pollution sources that did not reach groundwater by now (e.g. by soil excavation) and (b) to clean up groundwater already degraded by industrial pollutants (e.g. by pump and treat process). Expected benefits by 15 years would be the following: The possibility for households to use groundwater (e.g. for gardening) also in the vicinity of brownfields; The possibility to use the groundwater in some specific areas to produce tap water for Liège and surrounding areas if there were needs in the future; The possibility to transmit a groundwater quality of better quality to future generations; The improvement of the quality of the water feeding the Meuse, leading to the improvement of fauna and flora living quality. Section 4 This section deals with socio-economic characteristics of tha respondents, with classical questions related to gender, age, employment, education, size ofthe household, income, but also questions related to tha attachment to Liege, encountered environmental problems, quality of the information provided in the questionnaire and difficulty to answer to the WTP question. 3.2. DEFINING THE SCENARIO The text 4 describes tha proposed scenario of groundwater quality improvement. Individual benefits (WTP amounts) estimated by the questionnaire thus correspond to the value people would attach to go from the reference scenario to the improvement scenario. Differences between these two scenarios are underlined by Table 1. Expected benefits can be related to option values (future direct use), non-usa values and indirect use values. Current and future situation without Expected situation by 1 5 years if the Type of groundwater use measures measures are implemented (reference scenario) (improvement scenario) Current and future direct Groundwater use is to be avoided, Possibility to use groundwater for use especially In the vicinity of gardening also in the vicinity of brownfields brownfields (including for gardening) with the exception of Possibility to use groundwater in some some industrial uses. No use for specific areas to produce tap water for 22 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RVVM073 groundwater quality improvement tap water production. Liege if there were needs in the future Non use Groundwater quality will remain Groundwater quality will improve degraded for several decades Possibility to pass on to future generations a groundwater body of better quality Indirect use Contribution to the degradation of Improvement of the quality of water the Meuse water quality feeding the Meuse, improvement of flora and fauna living conditions Table 1. Impacts associated to the improvement scenario by type of groundwater use 3.3. TEST OF THE QUESTIONNAIRE The questionnaire was testad from tha 9* to tha 1 1'^ June 2010 by three BRGM researchers. 56 face-to-faca interviews were completed in the cities of Liège, Flémalle, Amay and Seraing. The following points were especially tested: the mode of data collection (mail versus face to face interviews), the general understanding of the questionnaire and visual supports, the credibility ofthe proposed scenario, tha payment vehicle, tha sampling area. 3.4. PRACTICAL ORGANIZATION OF THE SURVEY Recruitment A team of six students and four engineers/ researchers was constituted at the beginning of September. Training session A half day training session was organised at the University of Liege the 9* of September. Sampling procedure Quotas ware defined by age and sax. Tha sampling area was composed of 11 communes located at least partly on the RWM073 groundwater body and those partly located on tha RWM072 groundwater body at a maximum distance of 5 km upstream and downstream the groundwater body under study (Figure 6). Time spent in each commune was adapted day after day to ensure a good representativeness of the population living in the studied area. Data collection The questionnaire was administered from tha 13'^ to the 17* September 2010 in the communes of Liège, Engis, Amay, Visé, Oupeye, Herstal and Seraing. 531 face to face interviews were completed. BRGM-RP-59800-FR - Final report 23 Public perception and willingness to pay for the RWM073 groundwater quality improvement Ltgcnd - Rv«rs and *a»r eouries Communes Î* 1 RftW073 groundwiter body Figure 6. Sampling area and selected communes 24 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement 4. Valuation results: descriptive statistics 4.1 . RESPONDENT CHARACTERISTICS AND SAMPLE REPRESENTATIVENESS Socio-economic characteristics Table 2 provides soma general characteristics of tha sample. Characteristics Sample Study area Sample size 531 Age (mean) 47 Sex (% of men) 47 48 Employment (% employed) 34 39 Mean net income ( 1900 1810 Mean household size 2.3 2.2 % living above the RWM073 groundwater body 42 % depending from the RWM073 for tap water 0 % using water from a well in the RWM073 1.5 Table 2. General characteristics of respondents 53% of the respondents are women, 47% are men. Respondents ara aged 47 years on average. Tha mean household size is 2.3 persons. 27% of the respondents have at least a child younger than 18 years in their household. One third ofthe respondents are working (Table 3). Unemployed and retired people are slightly overreprasentad. 77% of tha respondents have an education level at least equal to the higher secondary^. The average income level (Figure 8) is 1900 euro par month par household. ^ Walloon education levels are classified into six categories: no diploma, primary, lower secondary, higher secondary, higher non-academic, higher academic. BRGM-RP-59800-FR - Final report 25 Public perception and willingness to pay for the RWM073 groundwater quality improvement Age of the respondents Population age distribution m the study area 1 I 20 40 60 80 100 age Figure 7. Comparison between respondents and population age distribution Number of respondents % of respondents % on the study area (Employed) workers 181 34% 39% Unemployed workers 87 16% 13% Retired 147 28% 22% * Students 74 14% 26% " Other 42 8% * population older than 64 years ** total population - workers - population > 64 years old Table 3. Comparison between respondents and population employment status The representativeness of the interviewees is quite good concerning the age distribution (Figure 7), gender, employment, income and household size . 26 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement Net monthly income distribution per household >6oooe- 5000-6000 €- 4000-5000 €- 3000-4000 € | 2000-3000 € - 1500-2000« 1000-1500« 500-1000 € «sooe 50 c 100 150 Frequency Figure 8 Net monthly income distribution per household • Localisation, mobility of the respondents The 11 communes of the sampling area are represented (Figure 9). The number of interviewed households by commune is quite representative of the distribution of the population although households of Liege and Herstal are overrepresented and households of Seraing, Flémalle and Saint Nicolas are underrepresented. A more accurate geographic distribution of the interviewees is provided by the Figure 10 with the boundaries of the former communes4. 2/3 of the respondents have been living in the study area since more than 20 years and more than the half have spent more than % of their life in the area (Figure 11). Less than 1/3 of the respondents consider as likely to move out from the area. From 1961 to 1983 the number of Belgian communes has been reduced from 2663 to 589. In this report we use the term "former commune" to refer to a commune of 1961 and the term "commune" to refer to a commune of 1983. BRGM-RP-59800-FR - Final report 27 Public perception and willingness to pay for the RWM073 groundwater quality improvement 70% -, oNunt«f of households n the commune total numb« ol h ou who Id s m the study area 60% - Nurt*et ol merwewed households in ihe commune lotal number of interviewed households 50% 40% 30% 20% 10»» // Figure 9. Distribution of interviews by commune Figure 10. Number of questionnaires completed by commune BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement Part of life spent in the study area >= 75% ^^^ 50 - 75% 25 - 50% <25% ^^^^^ 100 200 300 Do you plan to move out from the area? very unlikely| rather unlikely rather likely very likely 100 200 300 Figure 11. Parí of life spent in the study area and likelihood to move out • Respondents and the groundwater body 42% of the respondents live above the aquifer (Table 4). Only 19 respondents (3.5%) use water from a well (Figure 12) with eight of them being located on the aquifer (1.5%). Using water from rainwater harvesting systems is much more developed in the area (23% of the respondents). The Meuse alluvial aquifer is not used for tap water production from Engis to Herstal (RWM073 groundwater body). However the aquifer is exploited upstream and downstream to supply partly some communes with tap water as for instance Arrtay, Oupeye and Visé (RWM072 groundwater body). Respondents supplied by the RWM072 groundwater body represent 13% of the interviewees (Table 4). As expected, the proportion of RWM 073 direct water users is very low (1.5%). Whereas users will hold use and option use values and may well hold non-use values, non-users may hold option and non-use values or have negligible WTP (Bateman et al., 2006). Use values are thus expected to represent a small part of the value people attach to the improvement of the groundwater quality. BRGM-RP-59800-FR - Final report 23 Public perception and willingness to pay for the RWM073 groundwater quality improvement Characteristics Sample % living above the RWM073 groundwater body 42 % depending from the RWM073 for tap water 0 % depending from the RWM072 for tap water 13 % using water from a well in the RWM073 1.5 Table 4. General characteristics of respondents At home, do you use water from: 403 a rainwater harvesting system a well neither Figure 12. Number of respondents using water from wells or rainwater harvesting systems 4.2. PUBLIC KNOWLEDGE AND PERCEPTION OF THE MEUSE ALLUVIAL GROUNDWATER BODY Public perception of groundwater The first question of the survey tests how the respondent depicts a groundwater body (open- ended question). This question was answered by 84% of the respondents. A groundwater body is mainly described as "water in the soil" or "water in the ground" (23% of those who answered the question), as a "natural water reserve" (19%), a "water bubble" (8%), an "underground lake" (7%), a "cave" (7%), an "underground river" (4%), a "sponge" (1%). Groundwater is described as the result of infiltration (10%) of rain water (9%). Groundwater is seen as water into movement (7%) or that stagnates (2%). One third of the respondents have an opinion about potential uses of groundwater: 98% of them think groundwater is used, mainly for domestic water supply (61%) through springs or wells (22%). 11% also describe other types of services provided by groundwater: water filtering, water discharge into rivers, river flow regulation. Level of information/ knowledge Several questions regarding the respondent's prior knowledge of the sitiation described into the questionnaire were also included (Figure 13). The knowledge of the existence of the Meuse 3D BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement alluvial aquifer (cnappe variable) is quite low with only 20% of the respondents aware of it. The existence of brownfields in the study area (cfriche variable) is better known with 63% of the respondents being aware of it. Less than a quarter of the respondents had already heard about the groundwater degradation problem (info variable) described in the questionnaire (20%) or consider themselves well informed about it (4%). One third of the respondents knew the origin of their tap water (origin variable). These results confirm that the good to be valued in this study is particularly badly known. This low level of knowledge is quite common to the contingent valuation studies applied to groundwater in Europe. In fact groundwater is a complex and invisible resource which can be perceived very differently by households, especially when this resource is not directly used by the households through wells. The information delivered in the questionnaire is thus a major importance to ensure that respondents will all have the same level of knowledge of the groundwater pollution problem. 450 76% 400 67% 350 63% I "•— 4-1 • •g 300 —I- • • &250 • 37% • 01 Bf 1 Ol E 150 ü 1 1 3 F20% fH^ I 1 20% • 100 • 1 m m • 50 m® • • 1 1 • 1 +-1- 0 -H- M M m M yes no yes no well heard not at all yes no about it cnappe cfriche info origin Figure 13. Respondents'prior knowledge of the situation Perception of the groundwater degradation problem The majority of respondents is aware of the bad groundwater quality (Figure 14). Most of them think the groundwater quality has deteriorated during the last decade (40%) or that it did not evolve (30%). Most of them also think that the use of this groundwater may present some risks, especially for tap water production, agro-food production and gardening (Table 5). BRGM-RP-59800-FR - Final report 31 Public perception and willingness to pay for the RWM073 groundwater quality improvement 350 —m% 300 <-» -g 250 c 39% 40% 37% I 200 F 30% 30% o 150 U E 100 1 3 Z 50 = TJ c c •M o O ÍO o CU c -Q O 00 ro CLI X) E ai 4-v -C ro 00 m o ï ro ra D. c E Quality Quality evolution Risk Figure 14. Respondents' perception of the groundwater degradation problem Number of Groundwater use observations Tap water production 299 (56%) Agro-food processes 188 (35%) Gardening 136(26%) Green space watering 55(10%) Industrial processes 40 (8%) Table 5. Groundwater use likely to present a risk Likelihood of the description of the groundwater pollution problem (reference scenario) The reference scenario described in the questionnaire is considered as totally plausible (90%) or rather plausible (9%) by the vast majority of the respondents (Figure 15). BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement Is this description of the situation plausible? Very implausible Rather implausible Rather plausible Very plausible Figure 15. Likelihood of the reference scenario 4.3. PUBLIC PERCEPTION OF THE GROUNDWATER QUALITY IMPROVEMENT SCENARIO 98% of the respondents consider it is important to improve the RWM073 groundwater quality. A majority (58%) of the respondents estimates that reaching the proposed benefits by 2015 is realistic. However, 32% of them consider it as not entirely realistic and 9% as not realistic at all. Main quoted reasons are the lack of political will, the lack of financial means and the fact that 15 years won't be long enough to reach the situation described in the improvement scenario. Reaching these benefits by 15 years is: Very unrealistic Rather unrealistic Rather realistic Very realistic Figure 16. Realism of the improvement scenario BRGM-RP-59800-FR- Final report 33 Public perception and willingness to pay for the RWM073 groundwater quality improvement However, 66% of the respondents would be willing to contribute financially to this improvement by an increase in their water bill (Figure 17). 531 questionnaires 179 refuse to contribute (34% WTP=0) 352 accept to contribute 119 protest 60 true zeros (66% WTP>0) answers (22%) (11%) 412 stated WTP amounts (77% WTPiO) pWTP=40€moüsehoíd year Figure 17. Proportion of different types of answers The main motivation for paying is related to future generations and to the Meuse quality improvement (Table 6}. 34% of the respondents refusing to pay are classified as "true zeros": they attribute a zero value to the scenario because their income level is too low or they don't feel concerned by the groundwater quality improvement (Table 7). The other respondents refusing to pay are classified as protest answers: they refused/ failed to reveal the value they attribute to the scenario. The most commonly cited reason for protest answer was that respondents felt they already paid enough tax, followed by the polluters should pay (Table 7). When people are asked if they would contribute in the same way for an other groundwater body, 41% answer they would propose the same WTP amount, 30% would propose a lower amount and 29% wouldn't contribute. Motivation quoted Main motivation Respondents motivation for paying (N=352) (N=349) Possibility to transmit a groundwater body of 284(81%) 170(49%) better quality to future generations Improvement of the quality of water feeding the 270 (77%) 77 (22%) Meuse, improvement of flora and fauna living conditions Possibility to use groundwater in some specific 215(61%) 78 (22%) areas to produce tap water for Liege if there were needs in the future Possibility to use groundwater if you have or if 73(21%) 12(3%) you plan to have a well Table 6. Motivations for paying 34 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RVVM073 groundwater quality improvement Respondents motivation for refusing to pay IMotivation quoted (N=179) We already pay too many taxes 58 (32%) My income level does not allow me to pay 51 (28%) The polluter pays principle should apply 46 (26%) Money should be better spent 20 (1 1 %) Other reasons (protest answers) 20 (1 1 %) I would accept to pay but not through an increase in the water bill 19(11 %) I don't feel personally concerned, I don't expect any benefit from this 12(7%) scenario Lack of confidence 9 (5%) Table 7. Motivations for refusing to pay The average willingness to pay (WTP) is 46.9 when only positive WTP are considered. The average WTP is 40.1 when true zeros ara included. The general (Figure 18) and geographical (Figure 19) distribufion of the mean positive WTP are depicted below. BRGM-RP-59800-FR - Final report 35 Public perception and willingness to pay for the RWM073 groundwater quality improvement How much would you be willing to pay? II 200 400 600 wtp Figure 18. Distribution of positive WTP amounts Ugand Riven ins *•!•[ count* [ ] New commune i Mtu powt»« WTP ((. HI L. V . _ Figure 19. Mean positive WTP observed by commune 36 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement 5. Valuation results: econometric analysis 5.1 . GENERAL ASSUMPTIONS When considering the general context of tha groundwater problem under study, some general assumptions were formulated prior to the sun/ay: A low willingness to contribute rata is expected on the basis of the polluter pays principle. In fact the groundwater body is located in an heavy industrialised area, with polluting pressures originating mainly from industrial activities located on tha area since decades. A low WTP amount, for several reasons: o A low income level in the area and a high unemployment rate. o The groundwater body under study is only usad for industrial purposes. Direct use values for household are thus expected to ba zero. Tha WTP will thus theoretically only include indirect use, option and/or non-use values. o Respondents live in a heavily industrialised environment. For this reason thay may be rather insensitive to environmental problems and thus attribute low values for environmental management programs. On tha contrary, they may be affected by lots of environmental problems more palpable/ visible as air or soil pollution: groundwater quality problem may thus not represent a real issue for them. Additional assumptions were formulated concerning the factors that could influence the willingnass to pay rate and/or amount (Table 8): Factors Assumptions Geographic We expect that household living above the groundwater body are more location of tha concerned about the groundwater pollution problem and may have a higher respondent propensity to contribute (Al) Groundwater We expect that people having a well (A2a) and people supplied by tap water use from the Meuse alluvial aquifer (A2b) are mora sensitive to a groundwater quality improvement. Realism/ We expect that the realism/ likelihood level granted to the information provided likelihood by the questionnaire will influence positively tha willingness to pay rate and/or amount (A3). Importance We expect that the importance granted to tha groundwater improvement will influence positively the willingnass to pay rata and/or amount (A4). Benefits We expect that respondents giving a higher importance to indirect or non-usa value will have a higher propensity to contribute to tha groundwater improvement program (A5). Mobility We expect that people that spent an important part of life in the area and/or that do not envisage to move out from the area will have a higher propensity to BRGM-RP-59800-FR - Final report 37 Public perception and willingness to pay for the RWM073 groundwater quality improvement contribute (A6). Environmental Two contrasted assumptions may be formulated: problems . jj^g more respondents feel affected by environmental problems (in general) the mora thay are likely to be willing to contribute to environmental management program (in general), for instance the proposed groundwater quality improvement program (A7a). Tha more respondents feel directly affected by environmental problems such as soil or air pollution, the less thay would accept to contribute to management program devoted to improve groundwater quality which is not a priority for tham (A7b). Socio- According to the results obtained in other contingent valuation studies applied economic to groundwater, we expect that men (A8) with high income (A9), with high characteristics education level (A10) and with at least a child in tha household (Al 1) will have a higher propensity to contribute and to pay. Table 8. Expected effects ofthe main studied factors 5.2. LIST OF EXPLANATORY VARIABLES A series of explanatory variables have baan tasted in econometric models. They are listed and described in the table below (Table 9), with the number of observations in the sample, their mean (for quantitative variables) or frequency (for qualitative variables), thair standard error, thair minimum and maximum values. Their expected sign of influence on the willingnass to contribute and/or tha willingness to pay amount is also provided. They have been grouped into 12 categories: Geographic locafion Groundwater use Perception Information/ knowledge Likelihood/ realism Importance Benefits Mobility Environmental problems Socio-economic characteristics - Water bill Questionnaire valuation 38 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RV\/M073 groundwater quality improvement Expected Variable Description Obs Mean Std Dev Min Max influence distance Geographic distance from the centroid ofthe commune to the Meuse (m) 529 953 1 095 34 5 611 location hnappe the respondent lives above the RWM073 groundwater body 531 0,42 0,49 + Groundwater eaupluie the respondent uses water provided by a rainwater harvesting system 531 0,23 0,42 use eaupuits the respondent uses water abstracted from a well 531 0,04 0,19 + eaupultsnappe the respondent uses water abstracted from a well located in the RWM073 groundwater body 531 0,02 0,12 - + aepnappe the respondent is supplied at least partly from the Meuse alluvial aquifer 531 0,13 0,34 + usager the respondent uses water from the Meuse alluvial aquifer 531 0,15 0,35 + Perception qualité perception of the groundwater quality (1 : rather good, 2: rather bad) 526 1,61 0,49 1 2 +/- amello perception of the groundwater quality evolution (1 : rather improved, 2: no change, 3: rather degraded) 522 2,10 0,83 1 3 +/- risque the groundwater quality may constitute a risk if the water is used 531 0,63 0,48 + rind (...) for industrial purpose 531 0,08 0,26 ragro (...) for agro-food production 531 0,35 0,48 rrob (...) for tap water production 531 0,56 0,50 resp (...) for watering green spaces 531 0,10 0,30 rpot (...) for gardening 531 0,26 0,44 rautre (...) for other purposes 531 0,02 0,15 nbrisque number of uses for which groundwater quality may constitute a risk 531 1,35 1,40 5 + nbrisqueS the groundwater quality constitutes a risk for 5 types of uses 531 0,03 0,18 + Information/ origine the respondent knows the origin of its tap vrater 531 0,33 0,47 +/- knowledge cnappe the respondent knows the Meuse aquifer 531 0,20 0,40 +/- cfriche the respondent know/s the existence of brownfields in the area 531 0,63 0,48 - +/- info level of information of the respondent regarding the groundwater quality (0: not informed at all, 1 : has already heard about it, 2: well informed) 531 0,27 0,52 2 +/- Likelihood/ vraisemb level of likelihood of the reference scenario (from 0: not plausible at all to 3: quite realism plausible) 531 2,89 0,36 3 + réaliste level of realism attached to the improvement scenario (from 0: not realistic at all to 3: quite realistic) 529 1,73 0,93 - 3 + real ¡ste 1 the respondent finds the improvement scenario rather realistic 529 0,32 0,47 1 + BRGM-RP-59800-FR - Final report 39 Public perception and willingness to pay for the RWM073 groundwater quality improvement Importance import level of importance attached to the improvement of the groundwater quality (from 0: not important at all to 3: quite important) 531 2,80 0,47 3 + Benefits bpuits the possibility to use groundwater if the respondent has or plans to have a well is a motivation for contributing 531 0,14 0,34 + brob the possibility to use groundwater for tap water production if there were needs in the future is a motivation for contributing 531 0,40 0,49 + bgenfut the possibility to transmit a groundwater body of better quality to future generations Is a motivation for contributing 531 0,53 0,50 + bmeuse the improvement of the Meuse flora and fauna living conditions is a motivation for contributing 531 0,51 0,50 + bautre other motivation for contributing are quoted 531 0,05 0,21 + bprincipal main motivation for contributing 349 3,00 0,85 1 nbbenef number of motivations for contributing 531 1,63 1,44 + nbbenefS 5 motivations for contributing are quoted 531 0,01 0,11 + bpgenfut the possibility to transmit a groundwater body of better quality to future generations is quoted as the main motivation for contributing 531 0,32 0,47 bpmeuse the improvement of the Meuse flora and fauna living conditions is quoted as the main motivation for contributing 531 0,15 0,35 bpusage the main motivation for contributing is related to the direct use of the aquifer 349 0,26 0,44 +/- bnappe contribution of the respondent for an other aquifer (1 : would offer the same WTP, 2: would propose a lower WTP, 3: would not contribute) 349 1,88 0,83 1 bnappebis the respondent would propose a lower WTP for an other aquifer 349 0,30 0,46 + mobenef the respondent does not attach any benefit to the improvement scenario 531 0,02 0,15 rrevenu the respondent's income is too low 531 0,10 0,29 rfactur the respondent would accept to pay but not through an increase in the water bill 531 0,04 0,19 var1 other reason for not contributing 531 0,25 0,43 Mobility allege number of years the respondent has spent in the study area 531 34,75 22,84 91 + dliege probability to move out from the study area (from 0: very unlikely to 3: very likely) 531 0,96 1,14 ageliege allege/age 531 0,69 0,35 + adiiege ageliege/(dliege+1) 531 0,52 0,38 _ + sedentarity sedentarity level (0: unlikely to move out; 1 ; likely to move out) 531 0,68 0,47 Environmental ebruit the respondent is affected by noise pollution 531 0,49 0,50 problems epoleau (...) by water pollution 531 0,29 0,45 epolair (...) by atmospheric pollution 531 0,48 0,50 epolsol (...) by soil pollution 531 0,22 0,41 ebiodiv (...) by loss of biodiversity 531 0,31 0,46 40 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RV\/M073 groundwater quality improvement edech (...) by waste problems 531 0,55 0,50 - 1 eautre (...) by other environmental problem(s) 531 0,06 0,23 - 1 eprobleme - the respondent is affected by an environmental problem 531 0,82 0,39 1 + nbprobleme - number of environmental problems encountered by the respondent 531 2,33 1,92 6 + nbprobiemebis - the respondent is affected by at least 5 environmental problems 531 0,18 0,39 1 + Socio¬ sexe Gender (1 for woman) 531 0,53 0,50 1 - economic naiss characteristics year of birth 531 62,60 18,19 19 94 age age 531 47,40 18,19 16 91 seebenef the respondent will see the benefits of the improvement scenario (according to life expectancy) 531 0,80 0,40 - 1 + foyer size of the household 531 2,35 1,33 1 5 + enfant number of children < 18 years living in the household 531 0,42 0,82 - 4 + enfanti 1 child < 18 years lives in the household 531 0,15 0,35 - 1 actif employed worker 531 0,34 0,47 - 1 chom unemployed worker 531 0,16 0,37 - 1 retr retired 531 0,28 0,45 - 1 etud student 531 0,14 0,35 - 1 nactautres other activity 531 0,08 0,27 - 1 educ level of education 529 4,14 1,24 1 6 + revenu income class 524 3,90 1,69 1 9 rev income 531 1 901,60 1 252,20 - 6 500 + sqrt_rev square root of rev 531 41,25 14,15 - 81 + Water bill facteau the respondent knows its water bill 531 0,42 0,49 - 1 facteaum water bill amount 224 80,53 83,85 - 1 000 Questionnaire infoq quality of the information delivered by the questionnaire (from 0: absolutely insufficient to valuation 3: largely sufficient) 530 2,14 0,71 . 3 + qdiff difficulty of the wtp question (from 0: not difficult at all to 3: very difficult) 354 1,15 0,96 - 3 - qdiff3 the respondent estimates the wtp question as very difficult 354 0,07 0,26 - 1 - Table 9. List of selected potential explanatory variables and short description BRGM-RP-59800-FR - Final report 41 Public perception and willingness to pay for the RWM073 groundwater quality improvement 5.3. LOGISTIC REGRESSION OF WILLINGNESS TO PAY A logistic regression allows the prediction of a discrete outcome from a sat of variables that may ba continuous, discrete, dichotomous, or a mix of any of these. In a binomial logistic regression, the dependant variable is dichotomous: it can take tha value 1 or 0. In this case, the dependant variable Y is the willingnass to contributa that can take the value 1 with a probability of success 6 or tha value 0 with tha probability of failure 1-G. The binomial logistic regression estimates the expected value of Y as the probability that the willingness to contributa takes tha value 1 : E(Y)= 0. A series of binomial logistic regression were carried out to identify which predictor variable are statistically significant and how thay influence the willingness to contribute. The bast reduced model is presented in tha table below (Table 10). Logistic regression Number of obs 520 LR chi 2(11) 100.58 Prob > chi 2 0.0000 Log likelihooc = -276.87572 Pseudo R2 0.1537 accpayer Coef . Std. Err. z P>|z| [95% conf. interval] hnappe .6552245 .2273763 2.88 0.004*** .2095751 1.100874 nbrisqueS 2.009834 .9926301 2.02 0.043** .064315 3.955353 aepnappe .8291697 .3382325 2.45 0.014** .1662462 1.492093 import 1.158442 .2446392 4.74 0.000*** .6789583 1.637926 réaliste .4142357 1154629 3.59 0.000*** .1879326 .6405389 nbprobleme .1322406 .0575052 2.30 0.021** .0195324 .2449489 sexe -.4813639 .2155692 -2.23 0.026** -.9038718 -.0588561 enfanti -.610905 .2834622 -2.16 0.031** -1.166481 -.0553293 etud 1.744549 .4111022 4.24 0.000*** .9388036 2.550295 rev .0003506 .0001001 3.50 0.000*** .0001544 .0005468 eaupuits -.9658258 .5618259 -1.72 0.086* -2.066984 .1353328 _cons -4.307899 .7593729 -5.67 0.000 -5.796242 -2.819555 1% sign ificance level 5% sign ificance level 10% sig nificance leve 1 Table 10. results ofthe binomial logistic regression explaining the willingness to contribute 42 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement 1 1 variables are significant: Five variables are significant at the 1% level: living above tha groundwater body {hnappe=1), tha level of realism (réaliste) and tha level of importance (import) granted to the improvement scenario, being a student {etud=1) and the income level of the household (rev) have a positiva infiuence on tha willingness to contribute. Five variables are significant at a 5% level: estimating that groundwater quality may present a risk for Ave types of water uses {nbhsque5=1), being supplied partly from the Meuse alluvial aquifer for tap water {aepnappe=1), tha number of encountered environmental problems (nbprobleme), being a man (sexe=0), in a household without child younger than 18 {enfant1=0) infiuences positively the willingness to contribute. A variable is significant at a 10% level: having a wall {eaupuits=1) influences negatively the willingness to contribute. As tha number of households having a well is very small, this result should be used with caution. 5.4. ORDINARY LEAST SQUARE REGRESSION OF WILLINGNESS TO PAY (WTP>0) Unlike logistic regression, the dependant variable in an ordinary least square (OLS) regression is continuous. OLS regression is similar to logistic regression in that it is used to determine which predictor variables are statistically significant, diagnostics are used to check that the assumptions are valid, a test-statistic is calculated that indicates if the overall model is stafistically significant, and a coefficient and standard error for each of the predictor variables is calculated. In this case, the dependent variable is log(WTP). A log-linear regression was usad to identify tha predictor variables that influence the willingness to pay (WTP) value for strictly positive WTP values. A series of OLS regression were carried out. The best reduced model is presented in the table below (Table 11). BRGM-RP-59800-FR - Final report 43 Public perception and willingness to pay for the RWM073 groundwater quality improvement Source 1 SS df ivis Number of obs = 319 1-- F( 12, 306) 6.21 Model 1 58.6036076 12 4.88363397 Prob > F = 0.0000 Residual | 240.660977 306 .786473782 R-squared = 0.1958 X_ + Adj R-squared = 0.1643 Total 1 299.264585 318 9410836 Root MSE = .88683 log_wtp 1 coef. Std. Err. t P>|t| [95% conf. interval] h" distance I -.0001055 .0000467 -2.26 0.024** -.0001974 -.0000137 amelio I .1007009 .0628133 1.60 0.110 -.0228999 .2243016 rpot 1 .2271055 .1192644 1.90 0.058* -.0075767 .4617878 nbbenef5 I .7633274 .3734568 2.04 0.042** .028459 1.498196 bpusage j -.3036105 .1156413 -2.63 0.009*** -.5311633 -.0760578 bnappebis I .3876815 .1096307 3.54 0.000*** .171956 .6034071 sexe 1 -.2371432 .1020868 -2.32 0.021** -.4380241 -.0362622 enfanti I .2899846 .1484756 1.95 0.052* -.0021778 .582147 educ 1 .0989395 .0442271 2.24 0.026** .0119117 .1859673 sqrt_rev | .0079873 .0036275 2.20 0.028** .0008492 .0151253 nbprobiemebis! .3339447 .1278614 2.61 0.009*** .0823459 .5855436 qdiff 3 1 -.3598464 .2065499 -1.74 0.082* -.7662843 .0465914 _cons 1 2.41833 .2961777 8.17 0.000 1.835527 3.001132 1% signi fi canee level 5% signi fi canee level * 10% significance level Table 11. Results ofthe OLS regression explaining WTP values 1 1 variables are significant: Three variables are significant at the 1% level: quoting as main motivation for contributing to the program a benefit not related to a direct use of tha resource {bpusage=0), accepting to contribute also (but with a lower WTP) for an other groundwater body (bnappebis=1) and being affected by mora than five environmental problems {nbproblemebis=1) have a positive influence on the WTP amount. Five variables are significant at the 5% level: the proximity to the Meuse (distance), quofing five motivations for contributing to the groundwater quality improvement {nbbenef5=1), being a man (sexe=0), the education levai (educ) and the income level {sqrt_rev) influence positively the WTP amount. Three variables are signiflcant at the 10% laval: considering the groundwater quality as risky for gardening {rpot=1), having at least a child younger than 18 years in the household (enfanti =1) and considering that the WTP question is not vary difficult {qdiff3=0) influence positively the WTP amount. 44 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement 5.5. TOBIT REGRESSION OF WILLINGNESS TO PAY (WTP>0) Other models were then estimated using a Tobit regression , which allows using tha zero bids. Only true zeros ware included in tha analysis (protest are excluded). The dependant variable is log(WTP+1). The best reduced modal is presented in the table below (Table 12). Tobit regression Number of obs 397 LR chi 2(8) 91.79 Prob > chi 2 0 . 0000 Log likelihood = -696.11185 Pseudo R2 0.0619 log_wtp_vzl 1 coef. std. Err. t P>|t| [95% conf. interval] distance | -.0001291 0000741 -1 74 0.082* -.0002748 .0000167 eaupuits 1 -1.334356 4243836 -3 14 0.002*** -2.168728 -.4999832 realistel j -.2980695 .173678 -1 72 0.087* -.6395346 .0433955 import 1 1.007079 2132193 4 72 0.000*** .5878725 1.426285 sexe 1 -.4568601 1605055 -2 85 0.005*** -.7724269 -.1412932 educ 1 .2851127 0669966 4 26 0.000*** .1533921 .4168334 epolsol 1 .4583881 1888538 2 43 0.016** .0870862 .82969 rev 1 .0002902 .000064 4 54 0.000*** .0001644 .000416 _cons 1 -1.3821 .670313 -2 06 0.040 -2.69999 -.0642101 1% signi fi canee level 5% signi fi canee level * 10% significance level Table 12. Results ofthe Tobft regression explaining WTP values Eight variables are significant: Five variables are signiflcant at the 1% level: not using water from a wall {eaupuits=0), the level of importance granted to the groundwater quality improvement (import), being a man {sexe=0), the education level (educ) and the income level (rev) influence positively the WTP amount. A variable is significant at the 5% level: being affected by soil pollution (epolsol) influences positively tha WTP amount. Two variables are significant at the 10% level: living far to the Meuse (distance) and considering the improvement scenario as unrealisfic (realistel) influenças negatively the WTP amount. ' recommended if true zeros represent more than 10% ofthe respondents BRGM-RP-59800-FR - Final report 45 Public perception and willingness to pay for the RWM073 groundwater quality improvement 5.6. PREDICTED VERSUS OBSERVED VALUES The mean observed WTP is 46.9 when only positive WTP are considerad. The average WTP is 40.1 when true zeros are included. Predicted WTP are depicted by tha Table 13. Tha OLS regression model and tha Tobit regression both undar-astimate WTP. This may be partly due to tha fact that models do not reproduce high WTP values. Mean observed Mean predicted 95% confidence Model Nobs WTP WTP interval (( OLS (WTP>0) 319 46.9 31.5 30.0-33.1 Tobit (VVTP>0) 396 40.1 21.5 19.6-23.5 Table 13. Observed vs predicted WTP values 5.7. SYNTHESIS AND DISCUSSION Tha Table 14 proposes a synthesis of the significant variables for the three bast reduced models, with their expected sign and significance laval. The effect of the main groups of variables are discussed below and compared to the assumptions formulated in Table 8. Importance and realism of the scenario The more the respondent valuates tha improvement scenario as realist and important to be implemented, the mora ha is willing to contribute for this scenario. A3 and A4 are validated. Socio-economic characteristics Men {sexe=0) and people with higher income (rev) are mora willing to contribute, and propose higher WTP amounts. Coefficients of these variables have the expected sign: A8 and A9 are validated. People with higher education degree offer higher WTP amounts: A10 is validated. More surprisingly, people with a child younger than 18 years in the household are less willing to contribute, but whan they are, their WTP amount is higher than the others: A11 is not validated. 46 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement LOGIT OLS REGRESSION TOBIT REGRESSION Location hnappe(+)*** distance(-)** distance(-)* Groundwater aepnappe(+)** use eaupuits(-)* eaupuits(-)*** Perception nbrisque5C+)** rpot(+)* Know! edge/ information Likelihood/ realiste(+)*** realistel(-)* real i sm Importance import(+)*** import(+)*** Benefits nbbenef5(+)** bpusage(-)*** bnappebis (+)*** Mobi 1 i ty Envi ronmental nbprobleme(+)** nbprobiemebis (+)*** problems epolsol(+)** Socio-eco sexe(-)** sexe(-)** sexeC-)*** characteristic enfantl(-)** enfantl(+)* etud(+)*** educ(+)** educC+)*** rev(+)*** sqrt_rev(+)** rev(+)*** water bill Questionnaire qdiffSC-)* valuation Obs=520 Obs=319 0bs=397 Ps.R2=0.1537 Ps.R2=0.1643 PS.R2=0.0619 Obs.WTP=47 obs . WTP=40 p.WTP=32 p.WTP=21 *** 1% significance level ** 5% significance level * 10% significance level Table 14. Synthesis of the significant variables Groundwater use Having a well (abstracting water from the groundwater body under study or not) seams to influence negatively the willingness to contributa and the WTP amount. The sign ofthe coefficient is not tha expected one: A2a is not validated. This is maybe due to tha vary small number of households having a well. However, respondents supplied in tap water from the Meuse alluvial aquifer (upstream and downstream the boundaries ofthe groundwater body under study) are more willing to contribute than the others: A2b is validated. These people maybe consider that an improvement of the BRGM-RP-59800-FR - Final report 47 Public perception and willingness to pay for the RWM073 groundwater quality improvement RWM073 groundwater body quality may contribute to improve/ presen/e the quality of the groundwater used for thair tap water production. IVIobility Several variables related to the respondents' mobility ware tasted: the time spent in the study area (allege), the probability to move out from the study area (dliege), tha part of life spent in the study area (ageliege) and combinations of them (adiiege, sedentarity). None of tham were signiflcant: A6 is not validated. Impact of the geographic location Although the proportion of users is close to zero, people living above the aquifer {hnappe=1) are mora likely to contribute to an improvement of tha groundwater quality (72% in comparison with 62% for the others) and WTP amounts ara likely to ba higher for households living closer to the Meuse (distance)^. Several interpretations may be proposed: First, as underlined by Bateman at al. (2006), wa are in tha case of a compensating surplus valuation: respondents are asked their WTP for an improvement ofthe resource such that the future level of resource quality exceeds the present quality^. In this case, some present non-users may saa themselves as likely to become users of the improved good. This non-user to user conversion is mora likely to occur for households nearer to the resource than those further away. Tha possibility to use the groundwater in tha future is effectively quoted by 49% of the respondents living above the aquifer as a reason for contributing (39% for tha others). Respondents may feel more concerned about the pollution problem whan this pollution is located under their feet, even if thay do not usa nor plan to use the groundwater in tha future. Even if people living above the aquifer are more likely to contribute (Al is validated), it is important to note that positive WTP ara not limited to these people. Households living outside the boundaries of tha aquifer may also have positive WTP, decreasing with the distance to the Meuse. Distance to the Meuse seems in this case study to be the better proxy to assess the distance to the groundwater body. In fact the aquifer is described as an alluvial aquifer closely linked to the Meuse, respondents may thus valúate their distance to the aquifer as the distance to the Meuse and reveal their WTP according to this distance rather than to the exact distance to the aquifer boundaries (difficult to appreciate). '^ In opposition with an equivalent loss valuation in which respondents are typically asked to state their WTP to preserve the resource such that the future level of resource quality stays the same as its present quality. 48 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement How much would you be willing to pay? i ti i :!• i- • 0 2000 4000 6000 Distance to the Meuse (m) Figure 20. WTP amount as a function of the distance to the Meuse • Main reasons for contributing As underlined earlier in the report, the proportion of direct water users of the groundwater body is very low (1 -5%). Whereas users may hold use, option use values and non-use values, non- users may hold option and non-use values or have negligible WTP ( ). The survey shows that respondents' major reasons for contributing are not related to their current or potential future use of the resource but rather to non-use or indirect use values. The major quoted reason is the possibility to transmit a groundwater body of better quality to future generations (which refers to a bequest value i.e. a non-use value). Moreover, people considering an indirect or non-use benefit as the major reason for contributing (bpusage=0) are likely to have higher WTP amounts (51€ per household on average in comparison with 36€ per household on average for respondents considering a future use benefit as the major reason to contribute). A5 is validated. Even if the proportion of RWM073 groundwater users is close to zero, the observed percentage of people likely to contribute and observed WTP amounts are far from being negligible. In this case study, positive WTP are thus not limited to groundwater users and the main reason for contributing is not related to a potential future use of the resource. • Environmental problems Respondents feeling affected by a high number of environmental problems are more willing to contribute, with higher WTP amounts: A7a is validated. These respondents may be more aware than the others of environmental problems in their neighbourhood or effectively more affected by environmental problems than the others. As they are in majority not users of the groundwater body, they are not directly affected by groundwater pollution. Nonetheless, contributing to groundwater quality improvement may be a way for them to contribute to the improvement of their environment in general. • Warm glow effect A non-negligible proportion of respondents would also be willing to contribute for an other groundwater body {bnappe=1 or 2). As suggested by Rinaudo (2008), these respondents reveal that they derive moral satisfaction or a warm glow effect from the act of giving per se BRGM-RP-59800-FR - Final report 49 Public perception and willingness to pay for the RWM073 groundwater quality improvement (Kahneman and Knatsch, 1992), in addition to tha utility attached to the protecfion of the good under study. For these respondents, there may be a part of tha stated WTP amount not directly related to the aquifer being valued. In this case, stated WTP values may ovarastimate the real value that respondents granted to tha aquifer. Respondents that would be also willing to contributa for an other groundwater body but with a lower WTP amount (bnappebis=1) propose higher WTP values than the others (55 par household in comparison with 44 for the others). Knowledge and information level of the problem Respondents' laval of information on tha groundwater quality problem does not have any signiflcant effect on his willingness to contribute nor on his WTP amount. Respondents' information laval on tha existence ofthe groundwater body (cnappe), on the existence of brownfields (cfriche), on groundwater quality laval (info) and on tap water origin (origine) were tested but ware navar significant. The questionnaire provides the sama information to the respondents through a detailed description of tha aquifer, its uses, its quality management problem and tha benefits expected from and improvement of its quality. However, as highlighted by Rinaudo (2008), the appropriation of this complex information could have been different between those who discovered tha aquifer under study during the survey (situation of preferences construction) and those who had a prior knowledge ofthe aquifer and its management problem (situation of established prafarancas). Given that there is no differences, we can assume that non informed people have baan able to assimilate tha technical information provided to them, and that their stated WTP is as robust as for informed households. 50 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement 6. Benefits expected from an improvement of tlie groundwater body quality I In a perspective of cost-benefit analysis, the contingent valuation results can be used to assess tha total benefits expected from the proposed scenario of groundwater quality improvement. These total benefits can be estimated by aggregating the observed individual's benefits to tha population that may benefit from the groundwater quality improvement. Total benefits thus depend on both the benefits per parson and tha population of banaficiaries. Benefit per person The individual benaflt can be hare estimated as tha mean positive or null observed WTP. In fact, protest zero bids should be excluded from this estimation as these respondents are protesting by principle and do not reveal thair true utility (or absence of utility). The average observed individual benefit is estimated at 40.1 euros per household per year (41 1 observations), with tha 95% confidence intan/al [34.3; 45.8]. If needed, the Tobit regression modal can also ba usad to estimate tha WTP as a function of tha distance and socio-economic characteristics of the population, holding the other variables at their sample mean values. Population of beneficiaries Delimiting the populafion of benaficiahes raises tha issue of defining the market extent: how broadly should individuals' marginal benefit schedules be summed? Should this ba confined to these living in tha close vicinity of the good or extended across the region, county or even further (Bateman et al., 2006)? Defining the market extent is particularly challenging in this case as no direct use benefits can be related to an improvement of the aquifer. Bouscasse at al. (2009) proposes three options to delimit this market extent: (1) populafion living above the groundwater body, (2) population supplied by tap water provided by tha groundwater body, (3) population living above and/or supplied by tap water provided by the groundwater body. However none of these options seams relevant for an application to the case of the RWM073 groundwater body. In fact, results of the sun/ay (see §5.7) show that non negligible benefits exist for people living out of tha groundwater boundaries (option 1 not relevant) and for people which are not supplied in tap water from the groundwater body (option 2 and 3 not relevant). Two options are proposed in this report: The first option is to consider the market extant as the population of the sampling area used for the survey. The aggregation of individual benefits can than ba done by multiplying the average WTP by the number of households in the study area, given that our sample is considared as representative of the population of this area, both in terms BRGM-RP-59800-FR - Final report 51 Public perception and willingness to pay for the RWM073 groundwater quality improvement of socio-economic characteristics and in terms of geographic distribution (see §4.1). Tha population ofthe studied area was 428 843 inhabitants in 2010. Tha second option consists in delimiting tha market extent according to the distance decay effect as proposed by Bataman at al. (2006). As distance is a statistically significant and negatively related determinant of the WTP value, the distance at which WTP falls to zero can be estimated to defina tha boundary of tha relevant population. This can be done by using the distance decay function provided by the Tobit regression model and by solving for tha distance at which WTP equals to zero, holding tha non- distance variables at their sample mean values. From tha Table 15, wa obtain the following function: Ln(WTP+1)=2.922967962-0.0001291*distanca. The evolution of WTP as a function of the distance is depicted by Figure 21 . Distance at which WTP falls to zero is thus estimated at 22.641 km^. This distance thus defines the boundary of the relevant population which is estimated at 928 690 inhabitants in 2010®. TOBIT regression (N=397) Explanatory variables Coefficients Mean distance -0.0001291 924.5442 eaupuits -1.334356 0.04 realistel -0.2980695 0.3 import 1.007079 2.835 epolsol 0.4583881 0.225 sexe -0.4568601 0.525 educ 0.2851127 4.113065 rev 0.0002902 1918.75 cons -1.3821 1 TaWe 15. Coefficients and mean values of significant variables (Tobit regression model) This distance is an extrapolation of the distance decay function which has been designed on the basis of observations gathered in the sampling area, with a maximum distance of 6km (Figure 21). An more accurate estimation of the boundaries of the population of beneficianes would require to gather additional data in an extended sampling area. ® Population ofthe Walloon communes with a centroid located at a distance < 22.641km. 52 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement Figure 21. WTP - distance decay function (from the Tobit regression) Aggregation of benefits Two population areas can thus be defined: area 1 which is the sampling area and area 2 which is the additional area delineated by the distance decay function (Figure 22). Two distinct approaches are used to aggregate the benefits on these areas: • On area 1, we used the observed sample mean WTP and its 95% confidence interval as the mean individual benefit. • On area 2, we used the Tobit regression model to estimate the WTP. From the Table 15, WTP can be expressed as a function of the distance and the income10: ln(WTP+1)=2.366146712+0.0002902"income-0.0001291*distance Mean individual WTP were thus obtained through this function by commune (by using the mean 2008 income level by commune and the calculated distance of the centroid of the commune to the Meuse) and aggregated to the population of each commune. As values for the other variables were unknown in the area 2, we kept the mean observed values in area BRGM-RP-59800-FR- Final report 53 Public perception and willingness to pay for the RWM073 groundwater quality improvement Legend —— Rivers and waler courses I | Distance man boundaries ._ Communes of area I Communes of area 2 / Communes excluded from the analysis j Neighbouring countries Region boundaries Figure 22. Population of beneficiaries : delineation of area 1 and area 2 People are asked how much they would be willing to contribute each year during ten years. Aggregate benefits can thus be expressed per year or as total benefits when summed on 10 years and discounted with a 4% discount rate. 54 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement Area 1 Area 2 Aggregation using sample mean Aggregation using WTP WTP estimated from function Population 428 843 499 847 Number of households 194 929 227 203 Aggregate WTP (million 7.82 0.99 95% for aggregate (million [6,69; 8.93] Aggregate WTP (million 63.40 8.05 95% for aggregate (million [54.23; 72.41] Table 16. Aggregate benefits estimates Annual aggregate benefits expected from an improvement of tha RWM073 groundwater body are estimated at 7.8 million euros when considering tha sampling area (Table 16). Thay could reach 8.8 million euros when considering the full geographic area delineated by tha use of the distance decay function. Total aggregate benefits would thus reach between 63 and 71 million euros, depending on tha considered population of beneficiaries. BRGM-RP-59800-FR - Final report 55 Public perception and willingness to pay for the RWM073 groundwater quality improvement 7. Conclusion The contingent valuation survey was designed and implemented from May to September 2010 on tha most polluted part of the Meuse alluvial aquifer. 531 face to faca interviews ware completed. Tha representativeness of the interviewees is quite good concerning tha age distribution, gander, employment, income, household size and geographic location. As expected, tha proportion of direct groundwater users in the sample is vary low (1.5%). Results also confirm that the good to be valued is poorly known. The knowledge of the existence of the Meuse alluvial aquifer is quite low with only 20% of the respondents aware of it. The existence of brownfields in the study area is better known with 63% of tha respondents being awara of it. Less than a quarter of tha respondents had already heard about the groundwater degradation problem (20%)) or consider themselves well informed about it (4%). One third of tha respondents knew the origin of their tap water. However 98% of the respondents consider it is important to improve tha quality of the groundwater body and tha majority (58%i) estimates that reaching tha proposed benefits by 2015 is realistic. Two third of them would ba willing to contribute financially to this improvement by an increase in their water bill. Tha main motivation for paying is related to future generations and to the Meuse quality improvement. The average WTP is 46.9 when only positive WTP are considered. The average WTP is 40.1 whan true zeros are included. An econometric analysis is carried out to identify which factors infiuence significantly the willingnass to contribute and the WTP amounts. Three models are selected: a logistic regression modal (to explain the willingness to contribute), an ordinary least square regression modal (to explain the positive WTP amounts) and a Tobit regression model (to explain positive or true zeros WTP amounts). Results show that: Not surprisingly, tha more respondents consider the improvement scenario as realistic and important to be implemented, the more thay are willing to contribute for this scenario. Man and people with higher income are more willing to contribute, and propose higher WTP amounts. People with higher education degree offer higher WTP amounts. People living above tha aquifer are more likely to contribute. However positive WTP are not limited to these people. Households living outside the boundaries ofthe aquifer may also have positiva VVTP, decreasing with the distance to tha Meuse. Evan if the proportion of groundwater users is close to zero, the observed percentage of people likely to contribute and observed WTP amounts are far from being negligible. In this case study, positive WTP are thus not limited to groundwater users and the main reason for contributing is not related to a potential future use of the resource. Respondents feeling affected by a high number of environmental problems are mora willing to contribute, with higher WTP amounts. Respondents' level of information on tha groundwater quality problem does not have any significant effect on their willingness to contribute nor on their WTP amount. BRGM-RP-59800-FR - Final report 57 Public perception and willingness to pay for the RVVM073 groundwater quality improvement The contingent valuation results are than used to assess tha total benefits expected from tha proposed scenario of groundwater quality improvement. These total benefits can be estimated by aggregating observed individuals' benefits to tha population that may benefit from the groundwater quality improvement. Annual aggregate benefits expected from an improvement of the quality of the groundwater body are estimated at 7.8 million euros when considering the sampling area. They could reach 8.8 million euros whan considering the extended geographic area delineated by the usa of the distance decay function. Total aggregate benefits would thus reach between 63 and 71 million euros, depending on the considared population of beneficiaries. Benefits estimated through tha contingent valuation sun/ay are five to seven times higher than market benefits previously estimated by Hérivaux and Graveline (2009). Whan considering that average costs required for the remediation of the most polluted sites in tha Walloon Region are estimated between 1.25 and 2 million euros per site, these benefits are expected to cover tha remediation of nearly 40 brownfields. 58 BRGM-RP-59800-FR - Final report Public perception and willingness to pay for the RWM073 groundwater quality improvement 8. References Bateman, I. J., B. H. Day, et al. (2006). "The aggregation of environmental benefit values: Welfare measures, distance decay and total WTP." Ecological Economics 60: 450-460. Bouscasse, H., P. Defrance, et al. (2009). Evaluation das bénéfices attendus de l'amélioration de l'état des eaux souterraines en Région wallonne. Rapport flnal, Acteon/ Direction Générale des Ressources Naturelles et de l'Environnement - Région Wallonne: 78p. Hérivaux, C. and N. Graveline (2009). Economie analysis applied to groundwater degradation due to contaminated sites: Expected benefits related to a potential quality improvement ofthe RWM073 groundwater body. Deliverable 5.3 ofthe FRAC-WECO project. BRGM- RP-57051-FR: lOOp. Kahneman, D. and J. L. Knatsch (1992). "Valuing public goods: the purchase of moral satisfaction." Journal of Environmental Economics and Management 22(57-70). Rinaudo, J. (2008). Assessing the benefits of groundwater protection. A case study in the Rhine district, France.: 41 p. BRGM-RP-59800-FR - Final report 59 Geoscience (ora sustainable Earth Scientific and Technical Centre Water division, Nouvelles Ressources et Economie 3, avenue Claude-Guillemin Unit BP 36009 1039ruedePînvil!e 45060 Orleans Cedex 2 - France 34000 Montpellier- France Tel.: +33(0)2 38 64 34 34 Tel.: +33(0)4 67 15 79 90