The document discusses methods for establishing cost-effective wellhead protection zones to mitigate nitrate pollution from agricultural activities in the Moudania basin of Northern Greece. It outlines a two-stage methodological approach for identifying potential pollution sources and delineating protection zones based on groundwater flow equations, while analyzing various economic scenarios and their feasibility. The study emphasizes the importance of decision-making methodologies to effectively choose among alternative protection strategies for groundwater conservation.

1. ESTABLISHING COST-EFFECTIVE WELLHEAD PROTECTION ZONES TO CONTROL NITRATE POLLUTION FROM AGRICULTURE ACTIVITIES Aristotle University of Thessaloniki 12th International Conference on Environmental Science and Technology 8 - 10 September 2011 Rhodes island, Greece I. SIARKOS M. KATIRTZIDOU D. LATINOPOULOS

2. Groundwater Aquifers in a state of exhaustion Pollution because of human activities Difficult and slow diagnosis of pollution Two-stage methodological approach Introduction Measures Determination of protection zones Identification of potential pollution sources + Set of alternative scenarios Less expensive policy/cost-effective control + Major freshwater resource

3. Location: Hydrological basin of N.Moudania Northern Greece Prefecture of Halkidiki Description of the study area Moudania Basin Agricultural activities + Intensive irrigation Α) Geographical features

4. Characteristics: Area: 127.22 km 2 Av.Altitude: 211m Av.Ground slope: 1.8% Types of rock: loose & rocky formations Description of the study area Loose formations More hydrological interest Α) Geographical features

5. Assumptions a ) Constant pumping rate b ) Unaffected from nearby wells c ) Exclusive water supply 41 water-supply wells (8 .6 % of total ) Description of the study area B ) Water-supply wells

6. Description of the study area C ) Agricultural activities

7. Equations used: Distance to down-gradient null point Boundary limit Uniform-flow equation Distance to up -gradient Where: Q - well pumping rate K - hydraulic conductivity b - saturated thickness of the aquifer i - hydraulic gradient n e - aquifer effective porosity t - time of travel Delineation of protection zones Method Analytical Methods Uniform flow equations Darcy’s Law Criterion Time of Travel (ToT) A ) Theoretical framework

8. Zone I: 50 days (direct protection zone) Zone II: 2 years (considerable level of protection) Zone III: 5 years (less considerable level of protection ) Zone IV: 12 years (sufficient level of protection) Delineation of protection zones “ Time of Travel” limits Categories of protection zones Level of protection A ) Theoretical framework

9. Delineation of Zone II Delineation of protection zones Agricultural pollution Diffuse source of pollution Inside this protection zone the use of both pesticides and chemical fertilizers is prohibited A ) Theoretical framework

10. Delineation of protection zones W8 ( C ΝΟ3- = 80 mg / l ) W23 ( C ΝΟ3- = 107 mg / l ) W40 ( C ΝΟ3- = 81.5 mg / l ) Drinking water standards (50mg/l) (Council Directive 91/676/EEC) Wells selected Effect of cropping patterns Concentration of nitrates Selection criteria a) Main crop type in the land parcels around the well b) Results of chemical analyses of water samples B ) Well selection

11. Delineation of protection zones Well Area of zone II (m 2 ) Perimeter of zone II (m) W 8 58 , 690 1,059 W 23 15,150 477.3 W 40 45,690 909.2 C) Drawing of protection zones

12. Economical analysis Rely mainly on financial indicators & voluntary participation of farmers A) Alternative scenarios A. Expropriation of land parcels & changes in land use zoning B. Set aside (hold out of production) or pumping restrictions & farmers compensation C. Changes in water irrigation technology D. Cropping pattern changes in order to reduce fertilizer consumption E. Adoption of organic farming (non-use of nitrogen fertilizer) Regulated by local authorities Enforced to farmers Relatively straightforward computational approaches

13. Economical analysis 1 st step Identify initial cropping patterns Using GIS Visiting the area around the wells B) Cropping patterns Five main crops Olive trees Apricot trees Wheat Alfalfa Greenhouse vegetables

14. Well W8 Glasshouse vegetables (white colour) Alfalfa (green colour) Olive trees (yellow colour) W8 Economical analysis Protection Zone II B) Cropping patterns (W8)

15. Well W8 Glasshouse vegetables (white colour) Alfalfa (green colour) Olive trees (yellow colour) W8 Economical analysis Protection Zone II High implementation costs Environmentally – friendly irrigation method ( drip irrigation) B) Cropping patterns (W8)

16. Well W8 Glasshouse vegetables (white colour) Alfalfa (green colour) Olive trees (yellow colour) W8 Economical analysis No-nitrogen fertilizer application Protection Zone II B) Cropping patterns (W8)

17. Economical analysis Well W23 Wheat (gold colour) W23 Low-income Annual Non-irrigated Protection Zone II B) Cropping patterns (W23)

18. Economical analysis Well W40 Olive trees (yellow colour) Apricot trees (green colour) W40 High-income Multiannual Irrigated Protection Zone II B) Cropping patterns (W40)

19. Economical analysis Scenario A Scenario B Scenario B1 Scenario B2 Compulsory purchase of agricultural land ( expropriation of all parcels cultivated with olive trees, apricot trees and wheat ) Pumping restrictions to restrict the use of irrigation water in olive and apricot trees Set aside for wheat production C) Finally selected scenarios

20. (€/ha) Economical analysis Aim Cost of compulsory purchase ( CP ) Eliminating the use of fertilizers Expropriation & compensation to farmers Current value of agricultural land Objective (assessed) value - ILV F : initial land value factor (Ministry of Finance) - assessed value of a non-irrigated, annual parcel of land - R F : main cultivation factor - effect of various annual or multiannual crops on land values - I F : irrigation water factor - effect of irrigated or non-irrigated land on their objective values D) Cost estimates (Scenario A)

21. Compulsory purchase cost around the selected boreholes (total cost in Zone II) Highest cost per hectare in W23 due to its close proximity to the settlement boundary Economical analysis Highest total cost in W40 because there is a greater agricultural area that should be expropriated Well ID number Cultivated Crop Cost of compulsory purchase (€/ha) Total area ( ha ) Total cost of Scenario A (€) W 8 Olive trees 45,360 2 . 05 1 9 3 . 033 W 23 Wheat 80,000 1 . 15 9 92 . 704 W 40 Olive trees 45 ,360 3 . 81 3 19 9 . 914 Apricot trees 5 1,840 0. 5 20 D) Cost estimates (Scenario A)

22. Regional agro-economic indicators Fertilizers Pesticides Water use Market cost Labor costs Crop yields Crop prices Gross margin for irrigated and non-irrigated olive and apricot trees Economical analysis Objective Implementation cost Minimize the nitrate pollution Pumping restrictions & compensation to farmers Difference in gross margin between irrigated and dry farming conditions Compensation to farmers due to income losses Costs Annual income loss (dry farming conditions) Olive trees €915/ha Apricot trees €3306/ha E) Cost estimates (Scenario B1)

23. Only applied to wheat cultivation (low income, annual, non irrigated crop) Economical analysis Objective Implementation cost Minimize the nitrate pollution Set aside & compensation to farmers Total income losses of farmers Abandon their business for a number of years B2 scenario cost > B1 scenario cost Annual income loss (set aside policy) Wheat € 235.6/ha F) Cost estimates (Scenario B2)

24. Discount future implementation costs to a present value Economical analysis Scenario A form of a lump sum payment Scenario B form of “annual costs” Future annual costs of wellhead protection zones (Ct) for a given time horizon T (T>0) discounted at the discount rate r Time periods (T= 20, 30 and 40 years) - impact of time horizon on the expected total costs Discount rates (r = 2% and 4%) - sensitivity of our findings to the choice of discount rate G) Cost estimates (Scenario B) Present value (PV)

25. Implementation cost of pumping restrictions and set aside ( total cost in Zone II ) Economical analysis r Well ID Number Cultivated crop Area ( ha ) Implementation cost (€/ha) according to the time period Total implementation cost in Zone II (€) 20 years 3 0 years 4 0 years 20 years 3 0 years 4 0 years Scenario B 1 : Pumping restrictions in W 8 and W 40 2% W 8 Olive trees 2 . 05 1 15 , 0 00 20 , 5 00 36 , 6 00 30 , 668 42 , 006 75 , 023 W 40 Olive trees 3 . 81 3 15 ,00 0 20 , 5 00 36 ,600 85 , 108 116 , 572 186 , 47 5 Apricot trees 0.520 54 , 1 00 74 ,00 0 90 , 4 00 4% W 8 Olive trees 2 . 05 1 12 , 4 00 15 , 8 00 18 , 1 00 25 , 489 32 , 432 37 , 12 3 W 40 Olive trees 3 . 81 3 12 , 4 00 15 , 8 00 18 , 1 00 70 , 737 90 , 004 103 , 020 Apricot trees 0.520 44 , 9 00 57 , 2 00 65 , 4 00 Scenario B 2 : Set aside policy in W 23 2% W 23 Wheat 1 . 15 9 3 , 9 00 5 , 3 00 6 , 4 00 4 , 464 6 , 114 7 , 468 4% W 23 Wheat 1 . 15 9 3,21 0 4 , 1 00 4 , 7 00 3 , 7 20 4 , 721 5 , 40 4 G) Cost estimates (Scenario B)

26. Conclusions Well W23 Scenario A Scenario B r Well ID Number Cultivated crop Area ( ha ) Total implementation cost in Zone II (€) 20 years 3 0 years 4 0 years 2% W 8 Olive trees 2 . 05 1 30 , 668 42 , 006 75 , 023 W 40 Olive trees 3 . 81 3 85 , 108 116 , 572 186 , 47 5 Apricot trees 0.520 4% W 8 Olive trees 2 . 05 1 25 , 489 32 , 432 37 , 12 3 W 40 Olive trees 3 . 81 3 70 , 737 90 , 004 103 , 020 Apricot trees 0.520 2% W 23 Wheat 1 . 15 9 4 , 464 6 , 114 7 , 468 4% W 23 Wheat 1 . 15 9 3 , 7 20 4 , 721 5 , 40 4 Well ID number Cultivated Crop Total area ( ha ) Total cost of Scenario A (€) W 8 Olive trees 2 . 05 1 9 3 . 033 W 23 Wheat 1 . 15 9 92 . 704 W 40 Olive trees 3 . 81 3 19 9 . 914 Apricot trees 0. 5 20 Area with low income agriculture (wheat production) but with high value of land Set aside policy is by far the most cost effective measure in W23

27. Conclusions Wells W8 & W40 Pumping restrictions seems to be the most economically advantageous in W8 & W40 Scenario A Scenario B r Well ID Number Cultivated crop Area ( ha ) Total implementation cost in Zone II (€) 20 years 3 0 years 4 0 years 2% W 8 Olive trees 2 . 05 1 30 , 668 42 , 006 75 , 023 W 40 Olive trees 3 . 81 3 Apricot trees 0.520 85 , 108 116 , 572 186 , 47 5 4% W 8 Olive trees 2 . 05 1 25 , 489 32 , 432 37 , 12 3 W 40 Olive trees 3 . 81 3 Apricot trees 0.520 70 , 737 90 , 004 103 , 020 2% W 23 Wheat 1 . 15 9 4 , 464 6 , 114 7 , 468 4% W 23 Wheat 1 . 15 9 3 , 7 20 4 , 721 5 , 40 4 Well ID number Cultivated Crop Total area ( ha ) Total cost of Scenario A (€) W 8 Olive trees 2 . 05 1 9 3 . 033 W 23 Wheat 1 . 15 9 92 . 704 W 40 Olive trees 3 . 81 3 19 9 . 914 Apricot trees 0. 5 20 Low discount rates and long time horizon make the choice more difficult The decision maker may choose Scenario A because expropriation is more effective method in groundwater protection

28. Implementation cost depends on several parameters (area of protection zones, current cropping patterns and the land values) Not always an easy task Determined by many factors Conclusions Objectives of this study Exploration of all alternative scenarios Protect water supply wells from pollution Economic valuation of some of these scenarios Necessary further research focusing on a decision-making methodology Choosing the best scenario

29. “ When you drink the water, remember the spring”