Groundwater mapping and ressource assessment

Transcription

1 1 Groundwater mapping and ressource assessment Bjørn Kaare Jensen Deputy Director General Geological Survey of Denmark and Greenland 1 This event is jointly financed by ENV-TAIEF and the Danish Ministry of Environment and Food The Danish context Geography of Denmark Water supply Decentralized Water Supply Abstraction: 100 % groundwater Only simple water treatment (aeration and filtration through sand filter) 2

2 2 Groundwater types in Denmark 3 Integrated groundwater management in Denmark the 5 M s 4

3 3 Key elements of the Danish groundwater management concept A national program for mapping of groundwater aquifers A national groundwater monitoring program A national program for point source mapping and remediation of polluted sites A national water resource model the DK model Groundwater databases accessible to the public, including drinking water quality Soil and groundwater pollution remediation programmes A newly launched national cloud burst program for measures against flooding, including inland groundwater logging Several Research and Technology Development programs devoted to soil and groundwater 5 Integrated knowledge-based groundwater management system 6

4 4 The Groundwater Mapping programme in Denmark National groundwater mapping Cost 360 million Financed by water consumers paying extra 9 euro cents per m 3 of water The Danish Nature Agency is responsible for the mapping GEUS is responsible for setting the standards Local municipalities are responsible for the execution of action plans to regulate land use Most of the practical work was carried out by private consulting companies 7 Particularly valuable water abstraction areas (shown in purple) are mapped They cover about 40% (~ km2) of the land area of Denmark The groundwater mapping concept Detailed mapping of aquifers (size, location, interconnection) Mapping of groundwater vulnerability - especially identifying areas vulnerable to nitrate Action plans for groundwater protection 8

5 5 Groundwater mapping with SkyTEM Detailed information from the surface to depths of m Sand = potential for groundwater Clay = no groundwater 9 Data coverage Small ground-based TEM-mapping of areas a few km 2 in size Large SkyTEM-mapping areas up to 500 km 2 A large mapping area is required to understand the subsurface structures 10

6 6 Danish National Water Resource Model Objectives: Assess groundwater recharge at large scale / aquifer level Assess the size of the groundwater resources Assess the rate of exploitation Assess the size of the exploitable groundwater resource Basis for local detailed models Developed by GEUS using DHI models 11 What is Groundwater Monitoring? Groundwater monitoring collects relevant data for water policy and data mangement. Special focus on establishment of time series Groundwater quantity Groundwater level soundings Water Abstractions National hydrological model Groundwater quality Groundwater samples from: Monitoring wells Abstraction well at water plants No data from private drinking water wells 12

7 7 Design of the Danish monitoring programme Monitoring in 65 areas of 5-50 km 2 each with wells (700 samples/year) Additional monitoring in groundwater bodies at risk (140 samples/year) Multilevel monitoring in 5 deep groundwater well (4x80 samples every 3 years) Detailed monitoring of near surface groundwater in 5 small agricultural catchments (6x100 samples/year) A total of monitoring points One water sample: up to 97 parameters: 26 main elements, 14 heavy metals, 23 organic micro-pollutants, and 34 pesticides 13 Groundwater chemical resource assessment in Denmark Program is revised every 6 years Initial focus of nutrients, then on pesticides, now also on quantity integrating surface and groundwater Annual national reporting 14

8 8 Assessment of sustainable groundwater abstraction Sustainable groundwater abstraction has been assessed based on the national water resource model and selected indicators Last nationwide assessment Exploitable groundwater ressource 1 billion m 3 /year 15 Thank you 16