scholarly journals Modelling the recovery of surface water chemistry and the ecological implications in the British uplands

2003 ◽  
Vol 7 (4) ◽  
pp. 456-466 ◽  
Author(s):  
R. C. Helliwell ◽  
A. Jenkins ◽  
R. C. Ferrier ◽  
B. J. Cosby
Keyword(s):  
Surface Water ◽  
Base Cation ◽  
Surface Water Chemistry ◽  
Close Match ◽  
Acid Neutralising Capacity ◽  
Magic Model ◽  
Ecological Implications ◽  
Chemical Conditions ◽  
The Uk ◽  
Gothenburg Protocol

Abstract. Abstract: The MAGIC (Model of Acidification of Groundwaters in Catchments) model has been calibrated to three acid sensitive regions in the UK: Galloway, the South Pennines and Wales. These calibrations use the best available data for surface water, soil and deposition, from several UK data bases and regional sampling programmes. The model is capable of reproducing observed base cation and acid anion concentrations as reflected by a close match between observed and simulated acid neutralising capacity (ANC). Predictions to 2016 under currently agreed emission reductions, the Gothenburg Protocol, show that ANC greater than zero will be achieved at 100%, 86% and 100% of sites in Galloway, the Pennines and Wales, respectively. This indicates the potential for biological recovery and a return to ‘good status’ although chemical conditions remain some way from simulated pre-acidification conditions. In the longer term, beyond 2036 (20 years after compliance with the Gothenburg protocol), the model indicates that increased N leakage to surface waters may cause deterioration in the chemical status. Keywords: recovery, acidification, modelling, upland UK, ecology

scholarly journals An Assessment of the potential impact of the Gothenburg Protocol on surface water chemistry using the dynamic MAGIC model at acid sensitive sites in the UK

2001 ◽  
Vol 5 (3) ◽  
pp. 529-542 ◽  
Author(s):  
A. Jenkins ◽  
J. M. Cullen
Keyword(s):  
Surface Water ◽  
Nitrogen Leaching ◽  
Worst Case ◽  
Emission Reductions ◽  
Nitrogen Emissions ◽  
Surface Water Chemistry ◽  
Acid Neutralising Capacity ◽  
Magic Model ◽  
The Uk ◽  
Gothenburg Protocol

Abstract. The MAGIC model has been systematically calibrated to 12 sites in the UK, which form part of the UK Acid Waters Monitoring Network, using best available data. The model successfully simulates observed changes in major ions and acid neutralising capacity over the period 1988 to 2000. Predictions for the future are made assuming no further emission reductions from present day (constant deposition at current level) compared to reduced sulphur and nitrogen emission agreed under the Gothenburg Protocol (reduced sulphur dioxide emission by c.80%, nitrogen oxides by c.45% and ammonia by 20% by 2010). In addition, uncertainty in our understanding of future nitrogen dynamics is assessed using "best" and "worst" cases of nitrogen leaching in the model. The results clearly indicate the need to achieve further emission reductions in sulphur and nitrogen beyond present day levels to prevent continued surface water acidification. The predictions further indicate that if the emission reductions agreed under the Gothenburg Protocol are achieved by 2010 this will promote a recovery in acid neutralising capacity by 2020 at all sites. Differences between "best" and "worst" case nitrate leaching are relatively small, emphasising the need to achieve the sulphur reductions in the shorter term. In the longer term, beyond 2020, increased nitrogen leaching under the "worst case" leading to further acidification is likely indicating a need for further reduction of nitrogen emissions. Keywords: acidification, recovery, model, Gothenburg Protocol, nitrogen

scholarly journals Predicting regional recovery from acidification; the MAGIC model applied to Scotland, England and Wales

1998 ◽  
Vol 2 (4) ◽  
pp. 543-554 ◽  
Author(s):  
C. D. Evans ◽  
A. Jenkins ◽  
R. C. Helliwell ◽  
R. Ferrier
Keyword(s):  
Surface Water ◽  
Significant Proportion ◽  
Chemical Properties ◽  
Regional Patterns ◽  
Surface Water Chemistry ◽  
Surface Water Acidification ◽  
Magic Model ◽  
Recovery From Acidification ◽  
The Uk ◽  
Physical And Chemical

Abstract. A dynamic, process-based model of surface water acidification, MAGIC, has been applied to over a thousand sites across the UK. The model is calibrated to surface water samples collected during a survey for the Critical Loads programme, and utilises the best available and consistent estimates of soil physical and chemical properties, rainfall and runoff volumes, and deposition chemistry. A total of 698 sites were calibrated successfully. At these sites, surface water chemistry was reconstructed from 1850 to the present day, and forecast to 2050 based on future decreases in sulphur (S) deposition in response to the Second S Protocol. Model outputs capture distinct regional patterns of acidification and recovery. the most acidic present-day conditions are found in acid-sensitive regions of Northern England (the Pennines, Lake District and North York Moors). Although a significant proportion of sites in these areas failed to calibrate, those that did are predicted to have experienced severe historic decreases in acidic neutralising capacity (ANC) in response to high levels of acidic deposition. The model also indicates significant acidification in the moderate deposition areas of Wales and Galloway, whereas in the low deposition region of northern Scotland, acidification has been minor even in areas of acid-sensitive geology. ANC is forecast to recover at virtually all sites, with the greatest recovery predicted for areas currently subject to high deposition. The model indicates that the Second S Protocol, however, will not be sufficient to produce full recovery, with average ANC increases to 2050 counteracting just 27% of the simulated decline from 1850 to present day. Acidic conditions (ANC < 0) are predicted to persist until 2050 at a significant number of sites in Northern England, Wales and Galloway.

scholarly journals Modelling nitrogen dynamics at Lochnagar, N.E. Scotland.

2001 ◽  
Vol 5 (3) ◽  
pp. 519-528 ◽  
Author(s):  
A. Jenkins ◽  
R. C. Ferrier ◽  
R. C. Helliwell
Keyword(s):  
Surface Water ◽  
Nitrogen Saturation ◽  
Inorganic Nitrogen ◽  
Steady Increase ◽  
Worst Case ◽  
Emission Reductions ◽  
Surface Water Chemistry ◽  
Run Off ◽  
Magic Model ◽  
Gothenburg Protocol

Abstract. Controls on nitrate leaching from upland moorland catchments are not yet fully understood and yet, despite agreements on emission reductions, increased surface water nitrate concentrations may affect significantly the acidity status of these waters in the future. At Lochnagar, an upland moorland catchment in N.E. Scotland, 12 years of surface water chemistry observations have identified a steady increase in nitrate concentration despite no measured change in inorganic nitrogen deposition. The MAGIC model has been applied to simulate a "best case" situation assuming nitrate in surface water represents "hydrological" contributions (direct run-off) and a ‘worst case’ assuming a nitrogen saturation mechanism in the catchment soil. Only the ‘saturation’ model is capable of matching the 12 years of observation for nitrate but both model structures match the pH and acid neutralising capacity record. Future predictions to 2040, in response to the agreed emission reductions under the Gothenburg Protocol, are markedly different. The worst case predicts continued surface water acidification whilst the best case predicts a steady recovery. Keywords: nitrogen saturation, modelling, Lochnagar, Gothenburg Protocol

AN OVERVIEW OF FACTORS THAT INFLUENCE THE DEVELOPMENT OF CANADIAN PEATLANDS

1994 ◽  
Vol 126 (S169) ◽  
pp. 7-20 ◽  
Author(s):  
Dale H. Vitt
Keyword(s):  
Surface Water ◽  
Base Cation ◽  
Water Levels ◽  
Chemical Components ◽  
Surface Water Chemistry ◽  
Nutrient Contents ◽  
Peatland Development ◽  
The One ◽  
Peat Formation ◽  
Primary Division

AbstractCanadian peatlands can be classified into ombrotrophic bogs and minerotrophic fens, the latter subdivided into poor, moderate-rich, and extreme-rich fens, each with distinctive indicator species, acidity, alkalinity, and base cation content. If hydrology is considered the most important factor in peatland classification then the primary division must be between ombrotrophic bogs and minerotrophic fens; however both chemical and vegetational differences strongly indicate that the primary division of peatlands should be between acidic, Sphagnum-dominated bogs and poor fens on the one hand, and alkaline, brown-moss-dominated rich fens on the other. Although some metals such as sulphur and aluminum also vary along this gradient, nutrient contents of the surface waters do not. Bogs and fens are oligotrophic to mesotrophic wetlands that should be distinguished from eutrophic, non-peat-forming wetlands such as marshes and swamps by the presence in the former of a well-developed ground layer of bryophytes associated with relatively little seasonal water level fluctuation. Oligotrophy is probably maintained in bogs and poor fens by reduced water flow, whereas rich fens maintain mesotrophy by having larger water through-puts; however this is not well documented. Sphagnum appears to have real ecological significance, both in the initial stages of acidification and in controlling surface water temperature. Seasonal variation in surface water chemistry in all peatland types is relatively small, however precipitation events leading to changes in water levels do affect some chemical components. Although both autogenic and allogenic factors affect peatland development, initiation of peat formation and early development of peatlands during the Early and Mid Holocene were considerably influenced by regional climatic change. Later developmental patterns during the late Holocene and those seen at the present time appear to be more influenced by autogenic factors.

scholarly journals Continuous cover forestry: possible implications for surface water acidification in the UK uplands

2004 ◽  
Vol 8 (3) ◽  
pp. 306-313 ◽  
Author(s):  
B. Reynolds
Keyword(s):  
Surface Water ◽  
Base Cation ◽  
Forest Harvesting ◽  
Environmental Data ◽  
Water Acidification ◽  
Surface Water Acidification ◽  
Continuous Cover Forestry ◽  
Forestry Commission ◽  
The Uk ◽  
The Impact

Abstract. The effects of widespread conifer afforestation on the acidity of lakes and streams in the acid sensitive uplands of the UK has been researched extensively and has contributed to the development and implementation of national forest management guidelines (e.g. Forest and Water Guidelines; Forestry Commission, 1993). However, a recent policy document (Woodlands for Wales; National Assembly for Wales, 2000) has proposed a major shift in the management of 50% of the Forestry Commission estate in Wales from the current system of patch clearfelling to Continuous Cover Forestry (CCF). This scale of change is without precedent in the UK; no studies in the UK forest environment have examined the likely environmental impacts of CCF. However, the wealth of environmental data from studies of UK forests managed by patch clearfelling enables an assessment of the impact of a change to CCF on three issues of particular relevance to surface water acidification in the uplands; forest harvesting, soil base cation depletion and atmospheric pollutant deposition. Whilst there is uncertainty as to how even-aged stands will be transformed to CCF in the UK, guiding principles for CCF on acidic and acid sensitive sites should focus on those aspects of management which minimise nitrate leaching, encourage base cation retention within the soil-plant system and enhance base cation inputs from external (atmospheric) and internal sources (weathering). CCF may provide opportunities to achieve this by reducing the scale of clearfelling, increasing species diversity, changing the structure of plantation forests and maintaining uninterrupted woodland cover. Keywords: acidification, forestry, continuous cover forestry, clearfelling

Modelling the Effects of Acid Deposition: Estimation of Long-Term Water Quality Responses in Forested Catchments in Finland

1988 ◽  
Vol 19 (2) ◽  
pp. 99-120 ◽  
Author(s):  
A. Lepistö ◽  
P. G. Whitehead ◽  
C. Neal ◽  
B. J. Cosby
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Base Cations ◽  
Surface Water Quality ◽  
Mineral Weathering ◽  
Co2 Solubility ◽  
Forested Catchments ◽  
Deposition Rates ◽  
Magic Model

A modelling study has been undertaken to investigate long-term changes in surface water quality in two contrasting forested catchments; Yli-Knuutila, with high concentrations of base cations and sulphate, in southern Finland; and organically rich, acid Liuhapuro in eastern Finland. The MAGIC model is based on the assumption that certain chemical processes (anion retention, cation exchange, primary mineral weathering, aluminium dissolution and CO2 solubility) in catchment soils are likely keys to the responses of surface water quality to acidic deposition. The model was applied for the first time to an organically rich catchment with high quantities of humic substances. The historical reconstruction of water quality at Yli-Knuutila indicates that the catchment surface waters have lost about 90 μeq l−1 of alkalinity in 140 years, which is about 60% of their preacidification alkalinity. The model reproduces the declining pH levels of recent decades as indicated by paleoecological analysis. Stream acidity trends are investigated assuming two scenarios for future deposition. Assuming deposition rates are maintained in the future at 1984 levels, the model indicates that stream pH is likely to continue to decline below presently measured levels. A 50% reduction in deposition rates would likely result in an increase in pH and alkalinity of the stream, although not to estimated preacidification levels. Because of the high load of organic acids to the Liuhapuro stream it has been acid before atmospheric pollution; a decline of 0.2 pH-units was estimated with increasing leaching of base cations from the soil despite the partial pH buffering of the system by organic compounds.

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