b'Environmental geophysics chemistry. All of these data sets andof Denmark and Greenland, has a(by a liberal/conservative government), models are stored in the national datamuch-used, overall hydrogeologicalto be substituted with five regions base: GERDA. This is a valuable resourcemodel based on a geological model(that are now, for example, almost for future generations to use andof Denmark called the DKmodel. It isexclusively responsible for the health refine. The aim of the mapping was tomainly based on older drilling results;system), and the 271 municipalities eventually construct dynamic hydraulicthe new insights have not yet beenwere merged to form 98 new and larger models that would adequately describecompletely integrated. units.the flow of water, the interaction between precipitation, groundwater,The hydrological models based onSome of the important responsibilities and surface water, and be able tonew geophysical results and boreholeof the counties were resources, water predict the consequences of abstractioninformation are used to define newand minerals for example, and after the patterns so that the groundwatercatchments areas. However, therecounties were abolished, a few regional resource could be administered in aseems to be a scale problem. Theoffices were established to replace sustainable way. deeper parts of the models arethe old county-based departments. improved, but often the shallowerHowever, only one of those has From the very outset with the formingparts of the model are not optimal:survived. Another administrative of the HydroGeophysics Group, its mainthe geophysical results are sometimeschange that took place around this time task was development of geophysicalinsufficient and not infrequentlywas that the ministries of environment methodologies and software andover-interpreted. Often, once theand farming were merged. Considering an advisory function in relation tocatchment areas are defined, it isthe evident conflicts of (perceived) engineering companies by formulatinga difficult process to change them.interests, it took a very strong minister guidelines for instrumentation, fieldUltimately, it would be a costly affair toto insist on the protection of our work, data processing and inversion.re-evaluate the work that has alreadywater resources. However, presently This was decided through collaborationbeen done, and a better dialoguethey are again separate. From having agreements with the authoritiesbetween geophysicists and geologists/ been a county-based affair since responsible for the national mapping.hydrogeologists is needed - plus ofthe beginning in 1999, the National In the early days, the ambition ofcourse the necessary financing andGroundwater Mapping Project became the group was also to focus on themanpower. a state affair from 2007, and each integration of geophysical resultsA characteristic difficulty withmunicipality was now on its own in with the construction of hydraulicconstructing hydrogeological modelsterms of administering resources, a models, but unfortunately that aspectis that primary hydraulic data aretask not easily managed by many of never became prominent. This line ofquite sparse, making it difficult tothem. Consequently, the continuity and research is ongoing and is more or lessfind a model that is both reliable andcoordination of the decisions between successful, depending on the numbersufficiently complex to describe thestate, municipalities, regional offices, of hydrogeologists at the governmentcomplexities of the subsurface. Seenand the private water abstraction plants department and specific members offrom the geophysical perspective, thisis seriously challenged.the group. poses a challenge to come up with One of the aims of the National Traditionally, the work flow forattributes derived from the geophysicalGroundwater Mapping Project establishing a hydrogeologicalmodels that could eliminate somewas to establish a knowledge base model would start with geophysicalof the uncertainties in setting upon which restrictions on land use measurements and inversion resultshydrogeological models. Hydrauliccould be formulated that would that would then, together with othermodels are only weakly sensitive tosufficiently protect the most important information, form the basis for athe location of boundaries betweengroundwater resources against geological model, which in turn woulddifferent hydrogeological units, but thispollution from surface activities, be the basis for a hydrogeologicalgeometrical information can often bewhether domestic, industrial, or model. At the present stage of theprovided by geophysical models. Ideallyrelating to farming. There are quite a national mapping, setting up geologicalit would be helpful if geophysicalfew success stories from the past of and hydrogeological models is anresults, i.e. the subsurface distributionrelocating proposed town extensions, ongoing priority. One of the demandsof conductivity, could be used toas well as new areas for transport and on these activities is that the models forestimate hydraulic conductivity, but itindustry, based on hydrogeophysical neighbouring locations eventually mustis well known that no generally validinsights. But regulation of land use be seamless at the boundary, but at therelation exists. In some cases, locallyfor the farming sector is still not in moment, this is not always achieved. valid relations can be found, but this isplace, and the administration is clearly still an area of research. insufficient. There are presently of the An interesting aspect of the geophysicalorder of 3000 regulation areas, each mapping and the subsequentPolitical and administrative issues with an area less than 16 km2 - much geological interpretation is thattoo large considering the geological/many new geological insights wereIn Denmark, before 2007, publichydrogeological variability in most of produced, and quite a bit of thatadministration, political institutions,the country. This, and the ever-present contradicted previous concepts andand the right to collect taxes, was aresistance towards regulation from the truths. It was often a struggle to havethree-tier structure, divided betweenfarming lobby, who insists on being the new knowledge integrated in the271 municipalities, the 14 counties,regulated by data only, not models, old models. This is also an ongoingand the state. By January 1, 2007, themeans that effective regulations have process. GEUS, The Geological Surveycounty level was completely removednot yet been implemented.35 PREVIEW DECEMBER 2022'