Sensitivity analysis of a catchment-scale nitrogen model

McIntyre, Neil; Jackson, Bethanna; Wade, Andrew J.; Butterfield, D.; Wheater, H. S.

doi:10.1016/j.jhydrol.2005.04.010

Cited by 68 publications

(56 citation statements)

References 33 publications

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“…The sources of uncertainty are manifold (see Jakeman et al, 1993;New & Hulme, 2000;McIntyre et al, 2005;Wilby, 2005). The emission scenarios used in GCMs are subject to uncertainty in predictions of population growth, economic activity and, hence, emission rates.…”

Section: Model Uncertaintymentioning

confidence: 99%

A review of the potential impacts of climate change on surface water quality

Whitehead

Wilby

Battarbee

et al. 2009

Hydrological Sciences Journal

1,026

561

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It is now accepted that some human-induced climate change is unavoidable. Potential impacts on water supply have received much attention, but relatively little is known about the concomitant changes in water quality. Projected changes in air temperature and rainfall could affect river flows and, hence, the mobility and dilution of contaminants. Increased water temperatures will affect chemical reaction kinetics and, combined with deteriorations in quality, freshwater ecological status. With increased flows there will be changes in stream power and, hence, sediment loads with the potential to alter the morphology of rivers and the transfer of sediments to lakes, thereby impacting freshwater habitats in both lake and stream systems. This paper reviews such impacts through the lens of UK surface water quality. Widely accepted climate change scenarios suggest more frequent droughts in summer, as well as flash-flooding, leading to uncontrolled discharges from urban areas to receiving water courses and estuaries. Invasion by alien species is highly likely, as is migration of species within the UK adapting to changing temperatures and flow regimes. Lower flows, reduced velocities and, hence, higher water residence times in rivers and lakes will enhance the potential for toxic algal blooms and reduce dissolved oxygen levels. Upland streams could experience increased dissolved organic carbon and colour levels, requiring action at water treatment plants to prevent toxic by-products entering public water supplies. Storms that terminate drought periods will flush nutrients from urban and rural areas or generate acid pulses in acidified upland catchments. Policy responses to climate change, such as the growth of bio-fuels or emission controls, will further impact freshwater quality.Key words climate change; water quality; rivers; catchments; lakes; estuaries; ecology; hydrochemistry Une revue des impacts potentiels du changement climatique sur la qualité des eaux de surface Résumé Il est maintenant admis qu'un certain changement climatique d'origine anthropique est inévitable. Les impacts potentiels sur l'alimentation en eau ont fait l'objet de nombreuses attentions, mais peu de connaissances sont disponibles sur les changements associés en termes de qualité de l'eau. Les changements prévus en termes de température de l'air et de précipitations pourraient affecter les écoulements des rivières et par conséquent la mobilité et la dilution des substances polluantes. Une augmentation des températures de l'eau affectera la cinétique des réactions chimiques et, par combinaison avec les dégradations de la qualité, l'état écologique des hydrosystèmes. Une augmentation des écoulements aura pour conséquences des changements dans la puissance des cours d'eau et donc aussi des charges sédimentaires qui pourront altérer la morphologie des rivières et le transfert de sédiments vers les lacs, ce qui aura des impacts sur les habitats hydrobiologiques dans les systèmes lacustres et fluviatiles. Cet article fait une revue de tels imp...

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Section: Model Uncertaintymentioning

confidence: 99%

A review of the potential impacts of climate change on surface water quality

Whitehead

Wilby

Battarbee

et al. 2009

Hydrological Sciences Journal

1,026

561

View full text Add to dashboard Cite

show abstract

“…There has been developed a lot of mathematical and numerical models to simulate the water quality. These models are able to simulate the real situation at streams, however the range of the reliability and accuracy of the results is very wide [Abbott 1978, Jolánkai 1992, Pekárová and Velísková 1998, Říha et al 2000, Rankinen et al 2002, McInstyre et al 2005.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulations in the Mala Nitra stream by 1D model

Szomorová

Halaj

2015

ASP FC

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abstract. The development of the computer technologies enables us to solve the ecological problems in water management practice very efficiently. Hydrodynamical models which simulating transport of pollution in surface water are very demanding on input data and calculation time, but on the other side, they are able to simulate detailed effect of dispersion in surface waters. The paper deals with 1-dimensional numerical model HEC-RAS and its response on various values of dispersion coefficient. This parameter is one of the most important input data for simulation of pollution spreading in streams. Getting fair value, however, is in practice very difficult. One option is the most accurate simulation of tracer experiments carried out on the ground on the natural surface flow. For the pilot application was selected flow Small Nitra. Of longitudinal dispersion coefficient in the flow, or the flow of a similar nature (with and limit the rate of flow), were in the range 0.05 to 2.5 m 2 · s -1. The next task was carrying out the model sensitivity analysis, which means to evaluate input data influences, especially longitudinal dispersion coefficient, on outputs computed by 1-dimensional simulation model HEC-RAS. Sensitivity analysis model HEC-RAS also showed its adequate response to changes of the input parameter. Given the present results it can be stated that the HEC-RAS model responds to changes in the values of the longitudinal dispersion coefficient appropriately. HEC-RAS model has demonstrated its applicability to simulation of pollution in streams, and therefore is an appropriate tool for decision making related to the quality of water resources.

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“…One other aspect that needs to be considered in any modelling study is that of model uncertainty. INCA-N has been the subject of many uncertainty investigations, including Whitehead et al, 1998b, Wade et al, 2002, and McIntyre et al, 2005. All these studies demonstrate that process based models are difficult to calibrate and there is always some degree of equifinality occurring, whereby processes can duplicate behaviours making it difficult to find truly unique parameter sets.…”

Section: Inca-n Model Calibration and Validation Resultsmentioning

confidence: 99%

Modelling flow and inorganic nitrogen dynamics on the Hampshire Avon: Linking upstream processes to downstream water quality

Jin

Whitehead

Heppell

et al. 2016

Science of The Total Environment

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Managing diffuse pollution in catchments is a major issue for environmental managers planning to meet water quality standards and comply with the EU Water Framework Directive. A major source of diffuse pollution is from nitrogen, with high nitrate concentrations affecting water supplies and in-stream ecology. A dynamic, process based model of flow, nitrate and ammonium (INCA-N) has been applied to the Hampshire Avon as part of the NERC Macronutrient Cycles Programme to link upstream and downstream measurements of water chemistry. The model has been calibrated and validated against Environment Agency discharge and solute chemistry data, as well as a data set collected from a river site immediately upstream of the estuary tidal limit. Upstream measurements of denitrification at six sites have been used to evaluate nitrate removal rates in vegetated and non-vegetated conditions. Results show that sediments underlying vegetation were associated with significantly higher rates of nitrate removal than un-vegetated sediments (with an average increase of 245%). These data have been used to scale up rates of nitrate loss to the whole catchment scale and have been implemented via the model. The effects of streambed geology and macrophyte cover on catchment-scale nitrogen dynamics are explored and nutrient fluxes entering the estuary are evaluated. The model is used to test a strategy for nitrogen reduction assessed using a nitrate vulnerable zone (NVZ) methodology. It suggests that nitrate and ammonium concentrations could be reduced by 10% in 10 years and much lower nitrogen level can be achieved but only over a long time period.

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Sensitivity analysis of a catchment-scale nitrogen model

Cited by 68 publications

References 33 publications

A review of the potential impacts of climate change on surface water quality

A review of the potential impacts of climate change on surface water quality

Numerical simulations in the Mala Nitra stream by 1D model

Modelling flow and inorganic nitrogen dynamics on the Hampshire Avon: Linking upstream processes to downstream water quality

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