Nitrate reduction in geologically heterogenous catchments (NICA)
Nitratreduktion i geologisk heterogene oplande
PROJECT IS COMPLETED
Project period: 1 January 2010 - 31 December 2013
NICA will develop tools for assessing nitrate reduction in the subsurface between the root zone and the streams and methodologies for assessing at which spatial scales such tools have predictive capabilities.
Short description:
Nitrate leaching from agricultural areas is one of the major water resources management problems in Denmark. The efficiency of the existing general regulations is in average only 1/3, because 2/3 of the nitrate leaching from the root zone is reduced in the subsurface before reaching the streams. Today it is impossible to differentiate between vulnerable areas from where nitrate leaching reaches the surface water with very little reduction and robust areas where almost all leached nitrate is reduced. This is a serious constraint for designing cost-effective water management measures.
NICA will develop tools for assessing nitrate reduction in the subsurface between the root zone and the streams and methodologies for assessing at which spatial scales such tools have predictive capabilities. A new instrument will be developed for airborne geophysical measurements, MiniSkyTEM, dedicated for identifying geological structures and heterogeneities in the upper 30 m. Furthermore, a new geophysical method, MRS, will be introduced and the two novel geophysical methods will be tested against field data. State-of-the-art and novel hydrological models (DAISY, MIKE SHE/MIKE11, HydroGeoSphere, RWHET) will be applied and the effect of geological heterogeneity will be analysed by use of stochastic geological realisations using TProGS. A new concept, Representative Elementary Scale (RES), will be developed for assessing the minimum scale at which models, with a given data input, potentially have predictive capabilities. The studies will be conducted in a 5 km2, densely instrumented catchment (Lillebæk) and tested in a 100 km2 catchment (Norsminde Fjord), where farmers and authorities will be actively involved in evaluating possible measures for reducing the nitrate load to surface water in a cost-effective manner. The economic gain from a cost efficient location of the measures will be evaluated.
Kort beskrivelse:
Nitratudvaskning fra landbruget skal reduceres betydeligt med implementeringen af Vandrammedirektivet. Den hidtidige regulering har været ens for alle områder uden skelen til, at de naturlige betingelser for nitratreduktion i undergrunden varierer betydeligt afhængig af de geologiske forhold. Effekten af generelle reguleringer er i gennemsnit kun 1/3, da 2/3 af den udvaskede nitrat nedbrydes naturligt i undergrunden, inden det når vandløbet. En differentieret indsats vil derfor være langt mere omkostningseffektiv. Med den nuværende viden kan vi dog ikke med tilstrækkelig sikkerhed udpege, hvilke geografisk afgrænsede områder, der har en stor hhv. lille naturlig nedbrydningskapacitet.
NICA vil udvikle nye geofysiske metoder til at kortlægge lokale geologiske strukturer og eterogeniteter på meget lille skala med fokus på de øverste 30 m af undergrunden. NICA vil desuden udvikle metodikker til modellering af transport og nedbrydning af nitrat i undergrunden og til at vurdere betydningen af datatæthed og geologisk heterogenitet på pålideligheden af modellers prediktionsevne på forskellige størrelse af oplande.
Værktøjerne udvikles i to små velmoniterede landovervågningsoplande og testes efterfølgende i et større opland med normal datatæthed. I det store opland vil de mulige økonomiske gevinster ved anvendelse af de udviklede metoder og en differentieret indsats blive undersøgt, og der vil blive udarbejdet anbefalinger til en målrettet vandforvaltningsstrategi på oplandsskala.
IFRO contact
Name | Title | Phone | |
---|---|---|---|
Brian H. Jacobsen | Associate Professor | +4535336873 |
Project coordinator:
Jens Christian Refsgaard, Geological Survey of Denmark and Greenland (GEUS)
The project was funded by:
NICA has received funding from The Danish Council for Strategic Research; Programme Commission on Sustainable Energy and Environment
Total project amount: DKK 14.500.000