PREDICTING RECOVERY IN ACIDIFIED FRESHWATERS BY THE YEAR 2010, AND BEYOND

Contract EVK1-1999-00087 - RECOVER:2010

Part of the 'Sustainable Management and Quality of Water'

Ecosystem Functioning

Directorate General Research

The James Hutton Institute

This page is no longer updated. The Macaulay Land Use Research Institute joined forces with SCRI on 1 April 2011 to create The James Hutton Institute.

Please visit the James Hutton Institute website.

With new funding from RESAS as part of the Strategic Science Programme (2011-2016), long term projections of surface water acidification made to the year 2010 as part of the RECOVER:2010 were compared to observed chemistry.

In 1999, as part of the EU RECOVER:2010 project, the MAGIC (Model of Acidification of Groundwater In Catchments) model was used to project acidification of acid-sensitive European surface waters in the year 2010, given implementation of the Gothenburg Protocol to the Convention on Long-Range Transboundary Air Pollution (LRTAP). A total of 202 sites in 10 regions in Europe were studied.

With new funding from RESAS, staff in the Managing Catchments and Coast group of the James Hutton Insitute compared the forecasts made during the RECOVER:2010 project with measurements for the year 2010, to give a “ground truth” evaluation of the model. To find out more about this study click here to access the paper published in Environmental Science and Technology.

Upland Britain - Pennines

Scout Moor Reservoir,

DEM map with catchment boundaries The South Pennine uplands, in northern England, lie at the centre of the largest industrial area in the UK. Surrounding cities such as Manchester, Sheffield, Bradford and Leeds were at the forefront of the industrial revolution during the 19th Century, and the acute atmospheric pollution that resulted is evident throughout the region in soot contamination of blanket bogs. Although emissions have fallen in recent years, deposition remains high relative to other acid-sensitive areas of the UK; 1992-94 total non-marine sulphur deposition exceeded 30 kg S/ha/yr throughout the region, with total N deposition in the range 18-30 kg N/ha/yr (among the highest values recorded for either pollutant anywhere in the UK). Freshwater and terrestrial critical loads are severely exceeded throughout the region. The South Pennines consist of a narrow, relatively low-elevation (< 600m) corridor of moorland orientated approximately north-south, with extensive urban areas on either side (Figure 1). The upland area is almost entirely underlain by acid-sensitive Carboniferous millstone grits, with less sensitive coal measures to the west and east. Deep blanket peats cover much of the upland plateau, grading to ironpan stagnopodzols, stagnohumic gleys and brown earths at lower elevations. Land-use is primarily unimproved rough grazing at higher elevations, with some improved grazing on lower slopes. Afforestation is much less widespread than in other acid-sensitive areas of the UK, limited mainly to small plantations on the southeastern moorland fringe. The 60 sites sampled for this study are all small, headwater reservoirs, of which the region contains un unsually high number. Most are small earth embankments, constructed during the mid to late nineteenth century. All reservoirs were sampled in April 1998, and catchments were selected to contain less than 25% improved farmland.

Figure 1

Pennine District DEM

Almost half of all sampled sites had a negative ANC, and a pH below 5.0, with several sites having a pH below 4.0 (Table 1). Sulphate concentrations were extremely high (median 248 meq/l) and a median nitrate concentration in excess of 40 meq/l suggests that freshwaters throughout the region are at an advanced stage of nitrogen saturation. These data have been analysed in detail by Evans et al., (2000). Available long-term data from this region suggest that some degree of pH recovery has occurred since 1980, but this appears to have been slowed by increased leaching of nitrate (Evans and Jenkins, 2000).

Table 1: Summary statistics of the Pennine Resevoirs

	10^th Percentile	Median	90^th Percentile
ANC	-85	13	108
pH	4.08	5.27	6.60
SO₄	165	248	353
NO₃	26	41	77
Cl	175	243	544
SBC	285	601	964
NH₄	1.5	4.0	8.9
DOC	2.5	4.9	7.8

All concentrations meq/l except for pH (pH units) and DOC (mg/l).

Photo Gallery

Black Moss Reservoir

Broomhead Reservoir

Results from Pennines

For more information contact: Cev@ceh.ac.uk

REGIONS

References

Evans, C.D., Jenkins, A., Wright, R.F. (2000). Surface water acidification in the South Pennines I. Current status and spatial variability. Environmental Pollution 109: (1) 11-20.
Evans, C.D. and Jenkins, A. (2000). Surface water acidification in the South Pennines II. Temporal trends Evans CD, Jenkins A Environmental Pollution 109: (1) 21-34.