Water Conservation in Scotland - A Guide to proposals

Transcription

1 NITRATE VULNERABLE ZONES IN SCOTLAND REVIEW OF DESIGNATIONS 2009

2 CONTENTS 1. Introduction 2. Background 3. Nutrients in the water environment 4. Assessment Methodology 5. Monitoring Results 6. Water Framework Directive 7. Conclusions Annex A Review Group Membership

3 1. Introduction 1.1 The Scottish Government has a responsibility for maintaining and improving the quality of the water environment, both fresh and marine waters, in Scotland. For these purposes a number of Nitrate Vulnerable Zones (NVZs) have been identified in Scotland in order to protect human health and living resources from pollution to surface waters and groundwater, caused by nitrate from agricultural sources. The Government carries out a review of the designations at least every 4 years in line with the Nitrates Directive. This report summarises the review carried out in 2009 of the designations of NVZs in Scotland. 1.2 In 2003 the Scottish Executive introduced an Action Programme of measures which required farmers in the NVZs to adopt practices designed to prevent or minimise the run-off or leaching of nitrate to surface waters or to groundwater. The Scottish Government reviewed the Action Programme in 2008, and after consultation a substantially revised Action Programme came into force on 1 January The Article 10 Report for showed some signs of improvement for surface waters, but where groundwater sites could be compared more had increased in nitrate concentration than had decreased. There appeared to be no overall improvement for groundwater. 1.4 Since neither the Directive nor the Scottish Regulations specify the methodology for reviewing the NVZs, a Review Steering Group was set up as for the previous review. The Group was chaired by Scottish Government, with representatives from SEPA, NFU Scotland, Scottish Natural Heritage (SNH), Scottish Agriculture College, Scottish Rural Property and Business Association (SRPBA), and Scottish Water. The members of the Group are listed at Annex A. The Group met in April, June and October of The Group agreed the final draft of the report. 2. Background 2.1 The four NVZs in Scotland were designated under the Nitrates Directive (91/676/EEC). The Directive s objective is to protect human health and living resources from pollution to surface waters and groundwater caused by nitrate from agricultural sources. The Directive requires waters to be designated either where nitrate from agricultural sources results in concentrations of nitrate in surface waters or groundwater exceeding, or being likely to exceed, 50 milligrammes of nitrate per litre of water (50 mg NO 3 /l) or if the waters become eutrophic. Land draining to these waters must be designated as an NVZ, and legally binding rules, known as an Action Programme, must be put in place to reduce and prevent nitrate from agricultural sources polluting the water environment. 2.2 The Directive sets the following criteria for identifying polluted waters: Surface freshwaters which contain or could contain if preventive action is not taken (eg. Action Programme measures) more than 50 mg/l nitrate. 1

4 Groundwaters which contain or could contain, if preventive action is not taken, more than 50 mg/l nitrate. Natural freshwater lakes, or other freshwater bodies, estuaries, coastal waters and marine waters which are eutrophic or may become so in the near future if preventive action is not taken. 2.3 The Directive specifies that the following considerations must be taken into account when applying these criteria: The physical and environmental characteristics of the water and land; Current (scientific) understanding of the behaviour of nitrogen compounds in the environment (water and soil); and Current understanding of the impact of preventive action. 2.4 The Directive requires that at each NVZ review, changes and factors unforeseen at the previous review must be taken into account. The periodic nature of reviewing NVZs means that each review necessarily presents a snapshot assessment of nitrate pollution up to the time of the review. This review uses data up to and including Current designations 2.5 Four areas of Scotland are currently designated as NVZs (maps): Aberdeenshire, Banff, Buchan and Moray Strathmore and Fife Edinburgh, East Lothian and Borders Lower Nithsdale 2.6 These areas were identified, in 2002, from data on nitrate concentrations in surface waters and groundwater. Only a few rivers in Scotland were found to have nitrate concentrations as high as 40 mg/l, but higher concentrations were found in groundwater, mainly in the East of Scotland. The identification of groundwater NVZs was made on the basis of a risk assessment undertaken by the British Geological Survey (BGS) and the Macaulay Land Use Research Institute together with available monitoring data from SEPA. Records of public and private water supply from Scottish Water and local authorities were also used. Details of the methods used to identify the NVZs for designation in 2002 were given in The Development of a Methodology for the Designation of Groundwater Nitrate Vulnerable Zones in Scotland, a copy of which may be viewed at: The designation of Scottish NVZs is based on areas of high or rising nitrate concentrations in groundwater. These NVZ areas include all of the rivers whose nitrate concentrations were at or approaching 50mg/litre nitrate. The designations do not include the upland parts of catchments where there were clearly minimal contributions to the nitrate problem, especially areas of lightly stocked hill land. The NVZs amount to 14.2% of the land area of Scotland, but comprise a much higher proportion of the arable land area. 2

5 3. Nutrients in the water environment 3.1 Agriculture is the largest source of nitrogen found in surface waters or groundwater, although discharges from private and public waste water treatment works, as well as atmospheric deposition, also make a significant contribution. The agricultural nutrients are derived from fertilisers and from animal manures; they reach water by a combination of run-off from land, leaching from the soils, and losses from farm steadings. 3.2 The purpose of the Nitrates Directive is to reduce and prevent water pollution from agricultural sources of nitrate. High nitrate concentrations in groundwater and surface water may also entail eutrophication. Eutrophication is caused by excessive nutrients, mainly phosphates and nitrate, entering the water environment. This can cause an undesirable impact on water ecology, with the growth of algal blooms and increased growth of nuisance plant species. The effects of eutrophication include a decrease in biodiversity, loss of fish habitats and deterioration in the aesthetic standards of water bodies. There can also be taste and odour problems associated with algal blooms, and these could lead to higher treatment costs if drinking water sources were compromised. 3.3 As part of the review the requirements of two other Directives have been taken into consideration. These are the Urban Waste Water Treatment Directive (UWWTD) and the Water Framework Directive (WFD). 3.4 The UWWTD seeks to protect surface, inland and coastal waters from the contribution of nutrient discharges from waste water treatment works. Amongst other actions, this Directive requires the designation, as Sensitive Areas, of areas that are eutrophic, or likely to become so, due to nutrient from, but not exclusively from, waste water treatment works. Action also needs to be taken where it is found that nutrients from agricultural sources are a major contributory factor in the eutrophication of a Sensitive Area. In particular, where nitrate from agricultural sources is a significant contributory factor, the land draining into the Sensitive Area would be designated as a Nitrate Vulnerable Zone. 3.5 Compliance with the objectives of the UWWTD and the Nitrates Directive is complementary and fundamental to achieving the objectives of the WFD, which requires waters to achieve good chemical quality and, in respect of surface waters, good ecological status by 2015, subject to considerations of the economic and social impact. The Water Framework Directive includes in its programme of measures a requirement to tackle diffuse pollution from all sources, including substances contributing to eutrophication, in particular nitrate and phosphates. SEPA s river basin management plans covering the Scotland and Solway-Tweed River Basin Districts have identified water bodies which are failing their environmental objectives under the Water Framework Directive. SEPA has found that the dominant nutrient pressure in surface freshwaters in Scotland is from phosphates, rather than nitrate. 3.6 Figures from the British Survey of Fertiliser Practice (BSFP) show that the quantities of nitrogen applied in manufactured fertilisers have decreased markedly in recent years. The reduction in applications to grassland appears greater than on 3

6 tillage crops. There was a 42% reduction from 113 kg N/ha applied to grass in 2001 to 66 kg N/ha in 2008, compared to a 24% reduction in application to tillage crops from 147 kg N/ha (2001) to 111 kg N/ha (2008). There are similar reductions for phosphate. The downward trend is observed for Great Britain as a whole. 3.7 The reduction in the use of manufactured fertilisers may be accompanied by an improvement in the efficiency of Scottish farming s use of manures. Farmers are increasingly aware of the value of manure and slurry as a resource, rather than as a waste to be dealt with. More efficient use of manures will mean more are taken up by grass or crops and less lost to the water environment. 4. Assessment methodology Legislative requirement 4.1 The Protection of Water Against Agricultural Nitrate Pollution (Scotland) Regulations 1996 provides for Scottish Ministers to review and, if necessary, revise or add to the designations of NVZs every 4 years from 19 December This gives effect to the requirement in Article 3(4) of the Nitrates Directive which, in Annex I, sets out the criteria used for identifying nitrate vulnerable waters. Sources of information 4.2 The Review Steering Group agreed that the review should be based on SEPA s chemical and biological data and interpretations for surface water, groundwater and marine waters: Scottish Environment Protection Agency. Report of Four-Yearly Review Under the UWWT and Nitrates Directives. 4.3 The review made us of the following SEPA information: 2009 River Basin Plans for Scotland and Solway Tweed Districts. Groundwater trend classifications and both groundwater and estuary status classifications relevant to nitrates and associated eutrophication. These classifications were undertaken using data from the period Assessments of the risk of deterioration in groundwater WFD status. These were assessed using data from Assessments of the risk of eutrophication under the OSPAR Comprehensive Procedure. Surface water nitrate concentrations Models of nitrate leaching using land use, soils and meteorological information. 4.4 Since there is not as yet evidence of a substantial decrease in nitrate concentrations in groundwater, the Group did not examine the possible case for de-designation of any parts of the existing NVZs. A great deal of evidence has accumulated since the NVZs were designated in 2002, and there will be a case for reviewing the NVZ boundaries. 4

7 4.5 We propose that SEPA should carry out more detailed studies of nitrate concentrations in all 4 NVZs during the next 4 years leading up to the next review. Note on the groundwater monitoring data 4.6 Most groundwater in Scotland occurs below 1m depth in either fractured rocks, or in highly variable sand and gravel aquifers. Land use is also often highly spatially variable. There is therefore a tendency towards variability in conditions over space and time. High yielding groundwater abstractions are therefore the preferred monitoring site in order to provide an integration of groundwater conditions over as wide an area as possible. Where only lower yielding private abstractions are available, there is a risk that monitoring results will be affected by local point sources or by poor well construction. These sites therefore require continuous review to assess ongoing suitability. 4.7 In general, SEPA consider that a suitable site for monitoring nitrate from agricultural sources should have no evidence of being affected, or potentially affected, by point source or urban pollution. If there is a doubt, SEPA will recommend that the site is removed from the formal Nitrates Directive monitoring network. Sites close to point source pollution have the potential for causing high nitrate levels in future even if they are currently low. Where SEPA recommend the removal of a site with high nitrate concentrations that is located outwith an NVZ, SEPA will identify suitable alternative replacement sites. Where SEPA recommend the removal of a site where there are not high nitrate levels, SEPA will replace the site if it is located in an area where there would then be a significant gap in the network. 4.8 Over the next few years, SEPA will be significantly changing its water monitoring networks. The emphasis will be placed on monitoring sites in water bodies that: a) are at a high risk of deterioration in Water Framework Directive status, or b) are at less than good status but the confidence is insufficient to justify expensive measures or c) that require monitoring to assess the effectiveness of measures. This will mean less monitoring in lower risk situations. For groundwater, this will mean higher numbers of monitoring sites in Nitrate Vulnerable Zones and in at risk groundwater bodies outwith these zones. This will, in turn, improve the confidence in the assessments of the scale of the problem and of the effectiveness of measures. 4.9 There will also be emphasis on increased integration of monitoring from different water media and soil. This will be focussed in a series of integrated catchment studies undertaken in a rolling programme between 2009 and These studies are aimed at providing the evidence base for the effectiveness of 5

8 measures addressing the whole range of diffuse pollution impacts within the catchments. The question of whole-territory designation 4.10 The option of whole territory designation was considered by the review group. The advantage of whole territory designation is that controls designed to bring about improvements in water protection would be applied across the whole territory and that the problem of borderline areas would be reduced. The Directive allows for additional measures to be implemented in different areas, related to risk, as appropriate, but if this were adopted the problem of identifying boundaries would still occur It was noted that in Scotland there is great diversity of farming practice, with substantial areas where an NVZ Action Programme could not be expected to make any practical difference. Much of Scotland is grazed by sheep or cattle at low stocking densities, and nitrate loadings are low. In these circumstances there would be a substantial burden of record-keeping, which would be resented by farmers, without the prospect of any substantial environmental benefits to justify it. The group therefore rejected the option as inappropriate for the Scottish situation The RBMPs also contain details of catchments which SEPA consider as a priority for pollution reduction plans to be implemented. Assessment of the catchments will include identifying possible sources of diffuse pollution and poor practice. As a result action to improve water quality will be targeted to those catchments at greatest risk. 5. Monitoring Results Lower Nithsdale NVZ 5.1 The Group reviewed the report ( ) of a study by SEPA into whether additional monitoring was needed in Nithsdale. This found that there were still a few boreholes where nitrate concentrations were at or above 50 mg/l. It was also noted that in a few deeper boreholes, including ones used by Scottish Water for drinking water supply, nitrate concentrations had risen to about 30 mg/l. While the increase was slight, and concentrations are well below the drinking water limit of 50 mg/l, the situation needs to be kept under review and the revised Action Programme to be applied with a view to reducing the inputs of nitrate to groundwater bodies. The study did not attempt to be comprehensive, and it is recommended that further studies be carried out for Lower Nithsdale, as for the other NVZs. Sites outwith NVZs 5.2 The Review Group also considered reports from SEPA on a number of monitoring sites, outwith the NVZ boundaries, where high concentrations of nitrate were found. A summary of the findings is set out below. 6

9 Easter Ross (SEPA location ) Monitoring identified problems which were traced to an occurrence of injection of slurry from an intensive livestock facility in the late autumn, and poor storage practices. It was considered this was a site specific issue and would require joint action by SEPA and Scottish Government Rural Payments and Inspection Directorate. SEPA have taken action on this localised source and will keep the situation under review to assess the effectiveness of the measures. Moray Coast (SEPA location ) Initial monitoring results in 2003 were 80mg/l there was a major issue with the condition of the borehole. SEPA installed a new borehole, and readings are now <1 mg/l. Moray Coast (SEPA location ) The rising nitrate concentrations detected at the monitoring point were considered most likely to be due to seepage to groundwater from a slurry contaminated burn running east from an intensive livestock unit and passing within 30 m of the borehole. This slurry was traced to the eastern pig shed. SEPA have taken action on this localised source and will keep the situation under review to assess the effectiveness of the measures. Banff (SEPA location ) Elevated nitrates results were detected from a private water supply. However, after inspection it was found that the property had changed hands; the supply was no longer in use, and was being impacted by surface water contamination. The supply was therefore removed from the monitoring network. Results from nearby sites were re-assessed but nitrates were not found to be elevated across the area as a whole. SEPA will keep the situation in this area under review to assess future trends. Borders (SEPA location 16469) Routine monitoring identified nitrate concentrations in the borehole, reading just below the drinking water standard of 50 mg/litre nitrate. The data exhibited small seasonal fluctuations. Because of the positioning of the borehole, it is suspected that the groundwater may be compromised by a drainage ditch which receives drainage water from a farm steading. It was considered this was a site specific issue and would require joint action by SEPA and Scottish Government Rural Payments and Inspection Directorate. Stranraer Lowlands Elevated nitrate concentrations were observed in a groundwater monitoring borehole located in the Piltanton Burn catchment in the Stranraer Lowlands. The surface water catchment is an area of some 8,000 hectares with about 60 farm holdings. Initial routine quarterly analysis of groundwater samples from the borehole indicated unexpectedly elevated nitrate concentrations when first sampled in May Nitrate in subsequent analyses generally reduced but, in 2008, analyses were variable with a large increase followed by a sharp fall. Data from 3 nearby boreholes in agricultural areas of the same catchment show low concentrations (one of them averaging below 10 mg/l). 7

10 A SEPA report for the period was presented to the Review Group. An initial investigation was then undertaken on behalf of the Group by SEPA/SGRPID. The Group considered that further monitoring with cooperation from local land managers was required as the source was likely to be diffuse pollution with agriculture the dominant land use in the catchment. SEPA are planning a monitoring strategy, including access to new monitoring points, to further assess the situation and consolidate existing data. Together with information on historic land use and any future improvements, this monitoring will provide an integrated body of evidence to establish the extent of the impacted area and the effectiveness of improvements in land use. The Scottish Government intends to publish a separate paper on the Piltanton Burn catchment in 2010, once further investigation has taken place. 6. Water Framework Directive 6.1 The Group recognised that there are diffuse pollution problems, including the run-off and leaching of nutrients, in many parts of Scotland. The Group felt that improvements should be sought through a combination of advice, incentives and regulation with the aim of securing good quality in Scotland s waters in line with the objectives of the WFD. Guidance, notably in the PEPFAA Code, reported on the Article 10 Report, is aimed at improving farmers practices and thus protecting the environment. The Scotland and Solway Tweed River Basin Management Plans (RBMPs), published in December 2009, contain measures for the control of diffuse pollution. 6.2 The Scottish Government introduced in 2008 legislation which placed controls on certain activities which had the potential to cause diffuse pollution of the water environment. The Water Environment (Diffuse Pollution) (Scotland) Regulations 2008 contain measures to minimise diffuse pollution from: storage and application of fertilisers, keeping of livestock, cultivation of land, application of pesticide, and operating sheep dipping facilities. 6.3 As part of Water Framework Directive River Basin Management Planning, a national programme has been developed, which will support implementation of the Diffuse Pollution Regulations in Scottish Government intention is to ensure that all land managers are aware of their responsibilities regarding the control of diffuse pollution and the need for good practice. 6.4 A Diffuse Pollution Management Advisory Group was formed in 2009 to take forward the implementation of measures to mitigate diffuse pollution contained in the RBMPs. 7. Conclusions 7.1 The monitoring of nitrate concentrations in Scotland does not show an overall significant change, though there is some reason to expect, both from changes in 8

11 farmers practices and from the revised Action Programme, that there will be improvements. The group does not recommend any changes to the current NVZ boundaries. 7.2 Findings of high nitrate concentrations in a few sites outwith the NVZs have been investigated and in all but one case can be explained and remedied. In the case of the Piltanton catchment work is under way both to investigate the problem more thoroughly and to change farming practices in ways that will reduce the losses of nutrients to the water environment. This will inform a future Scottish Government decision on whether designation of this small catchment is indicated. 7.3 SEPA will continue to monitor concentrations of nitrate, both in groundwater and in surface waters, and will keep the monitoring network under review. The Group supports SEPA s plan to carry out in depth studies in all 4 of the designated areas in the next 4 years. Scottish Government June 2010 ANNEX A NVZ Designations Review Group Francis Brewis (Chair) Ian Speirs Martin Johnston Neil Henderson Andy Lyon Sarah Gillman Vincent Fitzsimons Mark Aitken Jonnie Hall Alan Crichton Graham Kerr Sarah Hutcheon Karen Smyth Scottish Government (SG) Scottish Government (SG) Scottish Government (SG) Scottish Government (SG) Scottish Government (SG) Scottish Water (SW) Scottish Environment Protection Agency (SEPA) Scottish Environment Protection Agency (SEPA) National Farmers Union of Scotland (NFUS) National Farmers Union of Scotland (NFUS) Scottish Agricultural College (SAC) Scottish Natural Heritage (SNH) Scottish Rural Property and Business Association (SRPBA) 9