1. Is the cost benefit analysis alone, relevant to conclude on disproportionate costs?
The example of the evaluation of of PoMs in the Sèvre Nantaise river basin

2. What is expected from the case study?
Giving an example of prospective POM for a pilot river basin, implementing a cost benefit analysis (2002) :
What kind of answers (PoM) can we give to pressure and associated impacts?
Feasibility of the economic approach
what are the costs of appropriate measures?
what are the associated benefits?
Can we conclude on disproportionate costs?
Lessons

4. Specificity of the Sevre Nantaise basin :
many and different uses and activities
context of a dialogue process between stakeholders (local masterplan
with involvement of local actors via a local commitee
A study has been done in 2002 :
need to be updated in the light of initial status objectives defined in
2004 for the entire basin and at the light of article 5 report
scenarios presented here are the ones of the study : really choices of stakeholders for the basin master plan could be different

5. network (physical chemical and biological)
Characterisation of the basin
Activities and uses
Existing monitoring
network (physical chemical and biological)
inhabitants
Drinking water : 10.6 Mm3/year
(3 dams)
Agriculture : livestock / wine / corn
Irrigation : 12 Mm3 per year
Industry : 96 main industries
Fishing (22000), boats, tourism
Main issues
point source pollution
non point source pollution
scarcity of water
Three scenarios have been set up

6. Scenario 1 : the baseline scenario
Basic ambition level concerning the quality and quantity of water resources
For the most part, basic measures defined to meet the requirements of sectorial directives (drinking water, urban waste-water, nitrates)
This scenario presents risks of not completely achieving the good water status for the entire river basin (efficiency problems)
potential gap from good water status?

7. Annual cost (millions €)
Scenario 1 : the baseline scenario
Measures
Annual cost (millions €)
Depollution in livestock farms
5.08
Protection of water catchment
0.17
Urban waste water treatment
0.508
Improvement of the flow
0.32
Total cost of scenario 1
6.078

8. Scenario 2 : enhancing the chance to reach the GES
Doing better than the basic level concerning the quality and quantity of water resources
On top of scenario 1, supplementary measures focused mainly on preventive drinking water protection (upstream of water catchment)
This scenario should allow to reduce the risk of not achieving the objective of good water status in time

9. Annual cost (millions €)
Scenario 2 : enhancing the chance to reach the GES
Measures
Annual cost (millions €)
scenario 1 +
6.078
Protected zones (upstream of water catchment)
1.311
Grass belts (upstream)
0.762
Treatment of phosphorus and nitrates for small units (upstream)
0.178
Total cost of scenario 2
8.331

10. Scenario 3 : a sustainable development scenario?
Maximal ambition level concerning the quality and quantity of water resources
On top of scenario 1, supplementary measures defined to :
apply agricultural best practice to the entire surface basin
optimize protection to catchment area
exceed the urban waste water directive requirements
improve the morphology of the rivers
This scenario should allow to achieve the good water status within the time limit of 2015
Disproportionate costs?

11. Annual cost (millions €)
Scenario 3 : a sustainable development scenario
Measures
Annual cost (millions €)
Scenario 1 +
6.078
Treatment of bateriological pollution
4.337
Grass belts
1.677
Extension of protected zones
4.162
Remediation of river banks and beds
0.873
Total scenario 3
17.13

12. The cost benefit analysis
Measures
Annual cost (millions €)
Scenario 1
6.078
Scenario 2
8.331
Scenario 3
17.13
Annual benefit (millions €)
0.5 2 23
drinking water treatment costs avoided (of scenario 1 and 2),
+ development of fishing
and tourism (with assessment of non marketable profits)

13. The benefits of scenario 3
The benefits of scenario 3 may seems important 23 million euros, it means about 21 additional millions compared scenario 2
The additional 21 million euros of benefits are for 90% due to a forecast potential development of tourism
If we have less optimistic trends for the tourism the benefits could be about 10 million euros
In this case the CBA of scenario 3 will largely be negative about 12 millions compared to the 17 millions of costs.

14. The CBA results for this RB
The three scenario of PoM have been analysed through a CBA
The 2 first scenario have a negative CBA
The third scenario « sustainable development » has a positive CBA for optimistic hypothesis for tourism
The benefits calculated for the third scenario remains uncertain the hypothesis is an increase of about 20% of the tourism which would have an important impact on the local economy

15. CBA results for this RB
The CBA remains an uncertain exercise largely influenced by the hypothesis
In terms of tourism, it was difficult to imagine how much benefits an improvement of the water quality will generate benefits (turnover)
For water bodies where there is no important touristic potential, the CBA remains often negative, doesn’t it means that there is nothing to do and just ask for derogation?
At the end, the CBA doesn’t reveal if the inhabitants, the farmers, and the industrialists of the RB will be able to pay the major part (art 9 cost recovery) of scenario 3 costs and if yes when (2015? , 2021? ,2027?,…)

16. Some lessons from the RB
CBA is an interesting tool to be used in the decision making process
CBA needs to combine a cost effeciency analysis of the possible alternative programmes of measures
CBA remains an uncertain exercise (hypothesis)
CBA will reveal often negative at places where there is not a possible important touristic development (for ground water WB it could be an important problem)
CBA alone doesn’t allow to conclude on disproportionate costs
To judge on disproportionate costs it is important to cross the CBA with an analysis of the social impacts (affordability) of the PoM.