Cost benefit analysis of investments in a groundwater well field and recharge area - development of a new tool

Ole Silkjær, TREFOR Water, Denmark

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TREFOR and TREFOR Water

TREFOR Water is a part of TREFOR - one of Denmarks major multi-energy companies

traditional utility company to supplying electricity, drinking water and district heating to the local area. a modern business that has evolved in line with the energy market and operates in a competitive market for commercial business areas

Building contractor/installation Broadband Energy consultancy Wind turbines Solar energy Health care products Off grid electricity solutions

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Introduction Sondre Kolding Well field as an example

Mapping of Groundwater resources in Denmark is conducted by the Nature Agency under the Danish Ministry of Environment The Nature Agency publishes all the results and hand them over to the municipalities In the Sondre Kolding well field area Kolding Municipality has produced an action plan in relation to drinking water, (Kolding Kommune 2013) The plan has been prepared in close cooperation with TREFOR Water. The action plan contains initiatives designed to protect groundwater from especially pesticides and nitrate The actions are funded by the local water utilities and their consumers To ensure that the right financial decisions are taken TREFOR Water uses cost-benefit analyses of each groundwater protection initiative in the catchment area. A tool to systematize and prioritize the actions is needed and developed Obtain an overview of facts The results are presented in this lecture

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Sondre Kolding well field Sondre Kolding Well field as an example

Groundwater mapping completed in 2009 The action plan from Kolding Municipality (2013) Annual abstraction permit is 850.000 m3 4 wells Catchment area is 1872 hectares Land use in catchment Groundwater protection by afforestation on 82 hectares

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Cost-benefit analysis tool Sondre Kolding Well field as an example

The tool is developed in cooperation with Christian Thirup, ALECTIA Prioritization of groundwater protection actions in relation to risk and finance Most cost-effective actions can be implemented Developed for Sondre Kolding well field The tool is later to be applied to the rest of TREFOR well fields The tool is based on worksheet calculations and maps

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Vulnerability and actions

Catchment area Well Protection Areas (BNBO) Vulnerability Areas of actions (IO)

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Recharge area

The recharge areas are calculated using a groundwater model They are prioritized in terms of the intensity of recharge

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Water flow time

The calculated groundwater flow times in the catchment area Groundwater protective actions are prioritized where groundwater has the shortest flow time to the abstraction wells Close to the wells and in the well protection areas (BNBO) Kilometers away from the wells.

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Land use

Land use is essential to groundwater protection Actions are prioritized where the specific land use represents the greatest threat to the aquifer Focus on nitrate and pesticides contamination Threat is greatest in areas with conventional agriculture, Christmas trees, greenery and orchards Land use dominated by intensive farming in the catchment area Detected polluted areas

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Levels of compensation Risk level and cost of risk elimination

Land usePesticides Nitrate Total Pesticides Nitrate+pesticides

Agriculture (intensive) 5 6 11 55.000 100.000Agriculture (extensive) 2 3 5 20.000 25.000Christmas trees and fruit orchards 6 4 10 60.000 110.000Forests 2 2 4 11.000 11.000Areas around buildings 5 3 8 50.000 50.000Industry 3 2 5 50.000 50.000Roads 0 0 0 0 0Lakes and Streams 0 0 0 0 0Recreation areas 2 2 4 0 0Nature (protected) 0 0 0 0 0Nature (not protected) 2 2 4 0 0Not classified 2 2 4 0 0

Risk Level Cost of risk elimination (kr./ha)

10.000 € = 75.634 Dkr.

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Land use risk level - pesticides

Land use risk in relation to the groundwater resource in terms of pesticides Red color is high risk areas Green color is low risk areas

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Land use risk - nitrate

Land use risk in relation to the groundwater resource in terms of nitrate Red color is high risk areas Green color is low risk areas The risk of groundwater contamination with nitrate is sligtly higher than of pesticides

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Cost of risk elimination concerning pesticides

Cost of risk elemination according to the land use Based on experience Negotiable within certain limits Danish kroner per hectare

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Cost of risk elimination concerning nitrate + pesticides

Cost of risk elemination according to the land use Based on experience Negotiable within certain limits Danish kroner per hectare

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Conclusive map and prioritized list

Prioritization of areas according to their cost efficiency Areas where the protective effect is greatest per Danish Kroner invested have the highest priority Prioritized list Summed cost Achieved safety The tool represents a screening and indicates where TREFOR get the most out of implementing groundwater protection efforts

- the actual cost-benefit tool

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Cost efficiency Pesticides

High cost efficiency (Green) Low cost efficiency (Red) 50% risk elimination in green areas 11,5 mio Dkr (1,55 mio €), 320 ha

- 10 20 30 40 50 60 70 80 90

100

- 10 20 30 40 50 60

Risk

elim

inat

ion

(%)

Cost of risk elimination (Mio. Dkr.)

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Cost efficiency Pesticides and Nitrate

High cost efficiency (Green) Low cost efficiency (Red) 50% risk elimination in green areas 17,7 mio Dkr (2.37 mio €), 333 ha

0%10%20%30%40%50%60%70%80%90%

100%

- 20 40 60 80 100

Risk

elim

inat

ion

Cost of risk elimination (Mio. Dkr.)

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Conclusion

Achieve the aim of the action plan Ground water protection Investment protection Secure our water supply systems Overview actions by visualization Prioritize actions Prioritize investments High cost efficiency

Benefits

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Thank you for your attention Ole Silkjær TREFOR Water Mail: olsi@trefor.dk