Wellhead protection zones

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

Groundwater

Aquifers in a state of exhaustion

Pollution because of human activities

Difficult and slow diagnosis of pollution

Two-stage methodological

approach

1.1. IntroductionIntroduction

Measures

Determination of protection zones

Identification of potential pollution sources+

Set of alternative scenarios

Less expensive policy/cost-effective control+

Major freshwater resource

Location:• Hydrological basin of N.Moudania • Northern Greece• Prefecture of Halkidiki

2.2. Description of the study areaDescription of the study area

Moudania Basin

Agriculturalactivities

+Intensiveirrigation

Α) Geographical features

Characteristics:Area: 127.22 km2

Av.Altitude: 211mAv.Ground slope: 1.8%Types of rock: loose & rocky formations


Loose formations

More hydrologicalinterest

Α) Geographical features

Assumptionsa) Constant pumping rateb) Unaffected from nearby wellsc) Exclusive water supply

41 water-supplywells

(8.6% of total)


B) Water-supply wells

Distribution of agricultural land per Municipal District

4%

23%

8% 16%

11%

7%

3%14%

14%

N.Moudania

St. Mamas

St. Panteleimon

Dionisiou

Zografou

N. Potidea

Portaria

Simantra

Flogita


C) Agricultural activities

Equations used:

KbiQX L 2

Distance to down-gradient null point

Boundary limit KbiQYL 2

Uniform-flow equation

Distance to up-gradient

Y

QKbi

XY 2tan

tnKiXe

t

Where: Q - well pumping rate K - hydraulic conductivity b - saturated thickness of the aquifer i - hydraulic gradient ne - aquifer effective porosity

t - time of travel

3.3. Delineation of protection zonesDelineation of protection zones

A) Theoretical framework

Method Analytical Methods

Uniform flow equations

Darcy’s Law

Criterion Time of Travel (ToT)

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)



“Time of Travel” limits

Categories of protection zones

Level of protection

Delineationof Zone II



Agricultural pollution

Diffuse sourceof pollution

Inside this protection zone the use of both pesticides and

chemical fertilizers is prohibited


B) Well selection

• W8 (CΝΟ3- = 80 mg/l)

• W23 (CΝΟ3- = 107 mg/l)

• W40 (CΝΟ3- = 81.5 mg/l)

Drinking water standards (50mg/l) (Council Directive 91/676/EEC)

Wellsselected

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

Well Area of zone II (m2) Perimeter ofzone II (m)

W8 58,690 1,059

W23 15,150 477.3

W40 45,690 909.2


C) Drawing of protection zones

4.4. Economical analysisEconomical analysis

A) Alternative scenarios

Rely mainly on financial indicators & voluntary

participation of farmers

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


B) Cropping patterns

1st stepIdentify initial

cropping patterns

Using GIS

Visiting the area around the wells

Five main crops

Olive trees

Apricot trees

Wheat

Alfalfa

Greenhouse vegetables

Well W8 • Glasshouse vegetables(white colour)• Alfalfa (green colour) • Olive trees (yellow colour)

W8


B) Cropping patterns (W8) Protection Zone II


W8


High implementation

costs

Environmentally – friendly irrigation

method (drip irrigation)



W8


No-nitrogen fertilizer

application



Well W23 • Wheat (gold colour)

B) Cropping patterns (W23)

W23

Low-income

Annual

Non-irrigated

Protection Zone II


Well W40 • Olive trees (yellow colour)• Apricot trees (green colour)

B) Cropping patterns (W40)

W40

High-income

Multiannual

Irrigated

Protection Zone II


C) Finally selected scenarios

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

F F FCP ILV R I (€/ha)


D) Cost estimates (Scenario A)

Aim

Cost of compulsory

purchase (CP)

Eliminating the use of fertilizers

Expropriation & compensation to

farmers

Current value of agricultural land

Objective (assessed) value

- ILVF: initial land value factor (Ministry of Finance) - assessed value of a non-irrigated, annual parcel of land - RF: main cultivation factor - effect of various annual or multiannual crops on land values - IF: irrigation water factor - effect of irrigated or non-irrigated land on their objective values

Well ID number

Cultivated Crop

Cost of compulsory purchase (€/ha)

Total area (ha)

Total cost of Scenario A (€)

W8 Olive trees 45,360 2.051 93.033

W23 Wheat 80,000 1.159 92.704

W40

Olive trees 45,360 3.813

199.914Apricot trees 51,840 0.520

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


D) Cost estimates (Scenario A)

Highest total cost in W40 because there is a greater agricultural area that should be expropriated

Regional agro-economic indicatorsFertilizersPesticidesWater useMarket costLabor costsCrop yields Crop prices

Gross margin for irrigated and non-irrigated olive and

apricot trees


E) Cost estimates (Scenario B1)

Objective

Implementation cost

Minimize the nitrate pollution

Pumping restrictions

& compensation to farmers

Difference in grossmargin between irrigated

and dry farming conditions

Compensation to farmers due to income losses

Costs

Annual income loss (dry farming conditions)

Olive trees €915/haApricot trees €3306/ha

Only applied to wheat cultivation

(low income, annual, non irrigated crop)


F) Cost estimates (Scenario B2)

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 scenariocost

>B1 scenario

cost

Annual income loss (set aside policy)

Wheat € 235.6/ha

Discount future implementation costs to a present value


G) Cost estimates (Scenario B)

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

T

t1 n t

t 1

CPV C ,...,C

(1 r)

Present value (PV)

Implementation cost of pumping restrictions and set aside (total cost in Zone II)

r Well ID Number

Cultivated crop

Area (ha)

Implementation cost (€/ha) according to the time period

Total implementation cost in Zone II (€)

20 years 30 years 40 years 20 years 30 years 40 years

Scenario B1: Pumping restrictions in W8 and W40

2%

W8 Olive trees 2.051 15,000 20,500 36,600 30,668 42,006 75,023

W40

Olive trees 3.813 15,000 20,500 36,60085,108 116,572 186,475

Apricot trees 0.520 54,100 74,000 90,400

4%

W8 Olive trees 2.051 12,400 15,800 18,100 25,489 32,432 37,123

W40

Olive trees 3.813 12,400 15,800 18,10070,737 90,004 103,020

Apricot trees 0.520 44,900 57,200 65,400

Scenario B2: Set aside policy in W23

2% W23 Wheat 1.159 3,900 5,300 6,400 4,464 6,114 7,468

4% W23 Wheat 1.159 3,210 4,100 4,700 3,720 4,721 5,404


G) Cost estimates (Scenario B)

r Well ID Number

Cultivated crop

Area (ha)


20 years 30 years 40

years

2%

W8 Olive trees 2.051 30,668 42,006 75,023

W40

Olive trees 3.81385,108 116,572 186,475

Apricot trees 0.520

4%

W8 Olive trees 2.051 25,489 32,432 37,123

W40

Olive trees 3.81370,737 90,004 103,020

Apricot trees 0.520

2% W23 Wheat 1.159 4,464 6,114 7,468

4% W23 Wheat 1.159 3,720 4,721 5,404

Well ID number

Cultivated Crop

Total area (ha)


W8 Olive trees 2.051 93.033

W23 Wheat 1.159 92.704

W40

Olive trees 3.813199.914

Apricot trees 0.520

5.5. ConclusionsConclusionsWell W23

Scenario A Scenario B

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

r Well ID Number

Cultivated crop

Area (ha)


20 years 30 years 40 years

2%

W8 Olive trees 2.051 30,668 42,006 75,023

W40

Olive trees 3.813

Apricot trees 0.520 85,108 116,572 186,475

4%

W8 Olive trees 2.051 25,489 32,432 37,123

W40

Olive trees 3.813

Apricot trees 0.520 70,737 90,004 103,020

2% W23 Wheat 1.159 4,464 6,114 7,468

4% W23 Wheat 1.159 3,720 4,721 5,404

Well ID number

Cultivated Crop

Total area (ha)


W8 Olive trees 2.051 93.033

W23 Wheat 1.159 92.704

W40

Olive trees 3.813199.914

Apricot trees 0.520

5.5. ConclusionsConclusionsWells W8 & W40

Pumping restrictions seems to be the most economically

advantageous in W8 & W40

Scenario A Scenario B

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

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

5.5. ConclusionsConclusions

Objectives ofthis 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

“When you drink the water,remember the spring”

Wellhead protection zones

Investor Relations

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