1 / 16

Land use effect on nutrient loading – nutrient models new assessment tools

This study explores the impact of land use on nutrient loading in Finland, utilizing advanced models like WSFS-Vemala and VIHMA for hydrological and water quality simulations. Covering 6200 sub-basins and 58,000 lakes, the models assess daily precipitation and temperature to simulate nutrient transport. By analyzing scenarios such as agricultural practices and climate change, the research identifies effective strategies for reducing nutrient loads, essential for improving the Baltic Sea's health. Comprehensive calibration processes enhance model accuracy to guide mitigation efforts effectively.

tess
Télécharger la présentation

Land use effect on nutrient loading – nutrient models new assessment tools

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Land use effect on nutrient loading – nutrient models new assessment tools Inese Huttunen, Markus Huttunen and Bertel Vehviläinen Finnish Environment Institute

  2. Basic structure of WSFS-Vemala • Hydrological WSFS-model: • Inputs daily precipitation and temperature • Simulates hydrological cycle on daily time step • Covers all Finland, 6200 sub-basins, 58 000 lakes • Simulated daily • Data-assimilation, ensemble forecasts • Water quality simulation with Vemala • Diffuse loading (agriculture and non-agriculture) • Point load, settlements, atmospheric deposition • Simulates transport in rivers and lakes • Total phosphorus, total nitrogen, suspended solids, organic carbon (TOC)

  3. VIHMA tool (Puustinen, SYKE) is used to simulateannualagriculturalload and Vemalaload is adjust • 1 100 000 fieldplotsaresimulatedseparatelybyknowingslope, plant, soiltype, P soil Relationshipbetweenconcentration and runoff / use of VIHMA annualloads • Runoff r (= r1+r2+r3+r4+r5) is divided into 5 classes rx, • each class has Ptot concentration cx,x which is calibrated • r1: runoff in runoff class 1, 0-1 mm/day • r2 runoff in runoff class 2, 1-3 mm/day • r3 runoff in runoff class 3, 3-6 mm/day • r4 runoff in runoff class 4, 6-10 mm/day • r5 runoff (unlimited) in runoff class 5, > 10 mm/day • Concentrationrelationshipwithrunoff

  4. Nutrientbalance in lakes Internal load Outflowing load Inflow loading Sedimentation Accumulation = Loading – outflow – sedimentation + internalloading AnnualPhosphorusbalance for Karhijärvi Inflowloading 10.2 t Outflowload 8.9 t Sedimentation 5.9 t Internalloading 3.2 t

  5. Calibration • Calibration is the process of modifying the parameters to a model until the difference between output from the model and observed data sets is minimum • Optimization criteria is: • all observation points located at the same calibration area are taken into calibration: • + there is a need to use all available observations in the calibration even if the are very infrequent (few times per year), • − more frequently observed points gets more weight in the calibration procedure. • appropriate weights for each type of observations are found and tested to reach the best possible calibration result • Water quality observations are not daily

  6. Phosphorusconcentration

  7. Phosphorusload

  8. Agricultural load 59% of the totalloading into ArchipelagoSea

  9. Use of VEMALA to simulatedifferentscenarios • Vemalacanbeused to simulatedpresentsituation • Wecanchangepresentloadings and simulateconcentrations and loadings in the rivercatchments in changedconditions: • Possiblechangesare: • Crop management changesby VIHMA / ICECREAM • Wetlandeffect • Scatteredsettlementloadingchanges • Pointloadchanges • Climatechangescenarios • Combination of abovementioned • Scenariosimulationshasbeendone in TEHO project for Aurajoki, Loimijoki and Eurajoki

  10. Wetlandsimulation • Allpossiblesmallditchcatchmentswitharea 20 – 200 ha • Whichhas at least 20% of agriculturalfields • Itspossible to simulate the effect of allpossiblewetlands, wecansimulatenutrientsedimentaion in wetland, plantuptake

  11. Scenarios of agriculturalpractices in TEHO • Bufferzones • Increase of vegetationcoverduring the winter (30%, 50%, 70% of the totalagriculturalarea): • Equally in allcatchment • On the steeperslopedfields • Using of mannuredecreasedby 50% • Decresedusing of P fertilizer Conclusionsfrom TEHO scenarios: • There is no one single method to reduceagriculturalloading, seceralreductionmethodsneed to becombined • The bestreductioncanbeachievedbycombination of: • Increasedvegetationcover on fieldsover 3% slope • Bufferzonesareestablished • Reduced P fertilizerapplication, that P soil < 14 mg/l • Best management practices of mannureapllication

  12. Summary • Agricultural load needs to be reduced to improve the state of the Baltic Sea • Mitigation measures are done on the field scale and there are needed tools to estimate what is the effect of mitigation measures on the river catchment scale • Nutrient load models (Vemala) can be used to simulate different scenarios how should the agricultural practices be changed to reduce the agricultural loading • There are no one single method to reduce agricultural loading, its a combination of methods • More detailed process description improves the models capability to simulate climate change or agricultural management scenarios

  13. Thank You! www.environment.fi/waterforecast

More Related