Contents

• Foreword by SEPA's Chief Executive
• Executive Summary
• Introduction
• State of the Water Environment
• Causes of Pollution and Pressures on the Water Environment
• Targets for Improving the Water Environment
• Summary of Issues Raised
• Glossary
• References

Foreword by SEPA's Chief Executive

The Scottish Environment Protection Agency (SEPA) has a wide range of environmental protection responsibilities covering discharges to the aquatic environment, emissions to air, the regulation of waste management and the control of radioactive substances. In addition to specific statutory powers to issue, monitor and enforce environmental licences, SEPA has more general duties to protect and improve Scotland’s environment.

In 1998, SEPA published its Environmental Strategy which identified and categorised, from SEPA’s perspective, the environmental protection priorities for Scotland. It provided SEPA with a practical framework for achieving its principal aim which is ‘to provide an efficient and integrated environmental protection system for Scotland which will both improve the environment and contribute to the Government’s goal of sustainable development’. In particular, the Strategy provides an overview of the integration of the differing regulatory regimes for air, waste, radioactivity and water and their interaction with wider social and
economic issues.

This Report on Scotland’s water environment has been developed within the framework defined by SEPA’s Environmental Strategy. It describes the condition of Scotland’s rivers, lochs, estuaries and coastal waters, moves on to assess the causes of environmental damage and then defines SEPA’s targets for protecting and improving the water environment.

This is the first time that specific improvement targets have been set for Scotland’s aquatic environment and these targets demonstrate SEPA’s commitment to improvements.

This publication is designed to contribute to discussions on the future management of Scotland’s water environment. The Scottish Parliament will introduce major changes to the political decision making process in Scotland. SEPA will ensure that it contributes objective information to assist the Parliament in undertaking its functions and intends this Report on Scotland’s water environment to be the first of a series which will help to inform debate across Scotland.

Alasdair C Paton
Chief Executive
May 1999



Executive Summary

This Report on Scotland's water environment has been developed within the framework defined in SEPA's 1998 Environmental Strategy¹ and has three main sections:

• State of Scotland's water environment: includes information on water quality, water quantity and habitat quality.
• Causes of pollution and pressures on the water environment: details the factors which have had negative impacts on the water environment.
• Targets for improving the water environment: SEPA has set targets for water quality improvements for 2000 and provisional targets for 2005. Information on targets to improve the Agency's knowledge of water quantity and habitat quality have been included.
  
  

State of Scotland's water environment

The Report contains information on water quality in rivers, canals, lochs, estuaries and coastal waters. Less detailed information is available on groundwater quality, the impacts of water quantity on ecology, and habitat quality. Water quality information from 1996, the year in which SEPA began operations, is presented in the Report and will be used as a baseline against which progress is measured. As lochs are currently classified on a five year cycle, data from the 1995 loch classification scheme are used.

Rivers: SEPA classifies over 50,000 km of rivers in Scotland. In 1996, just over 91% of the classified river length was of excellent or good water quality. Over 4,000 km of rivers were classified as polluted (fair, poor or seriously polluted classification).

Lochs: SEPA currently classifies the 150 lochs in Scotland with surface area above 1 km² as well as 23 smaller lochs. In 1995, 143 lochs were of either excellent or good water quality, while 30 lochs were classified as polluted (fair, poor or seriously polluted classifications).

Estuaries: SEPA classifies over 810 km² of estuarine waters in 32 estuaries. In 1996, 96% of the estuarine waters in Scotland were of excellent or good water quality while approximately 31.5 km² were classified as polluted (fair/poor or seriously polluted classifications).

Coastal waters: SEPA classifies over 6,900 km of the 11,800 km of coastal waters. In 1996, over 96% were classified as either excellent or good water quality while approximately 250 km were classified as polluted (fair/poor and seriously polluted classifications).


Causes of pollution and pressures on the acquatic environment

An assessment was carried out of all sites classified as fair, poor or seriously polluted in 1996 (1995 for loch water quality classification).

Rivers: Sewage effluent and diffuse agricultural pollution were the most significant causes of water pollution and accounted for 34% and 26% of polluted river water respectively. Acidification and urban drainage were the third and fourth most significant causes of river pollution accounting for 12% and 11% of polluted river length.

Lochs: Diffuse causes of pollution such as acidification, diffuse agricultural pollution and forestry affected over 80% of polluted lochs.

Estuaries and coastal waters: Sewage effluent was the most significant cause of pollution in estuaries and coastal waters affecting 92% and 89% of polluted water respectively. Industrial effluent similarly affected 43% and 11% respectively of the polluted estuarine and coastal waters.


Targets for improving the water environment

SEPA will direct its resources towards improving the most polluted waters in Scotland and national water quality targets have been set for poor and seriously polluted waters. The Report includes the following water quality targets for 2000 and provisional targets for 2005.

Rivers: Compared with 1996, SEPA will achieve a 20% reduction in the overall length of poor and seriously polluted rivers by the end of 2000 and will aim to increase this to a 45% reduction by the end of 2005.

Lochs: Only three lochs are currently listed in the poor or seriously polluted categories. SEPA considers that only one can be improved to fair water quality by the end of 2005.

Estuaries: Compared with 1996, SEPA will achieve a 20% reduction in the overall area of fair/poor and seriously polluted estuaries by the end of 2000. It does not consider that further improvements can be achieved until after 2005.

Coastal waters: Compared with 1996, SEPA will achieve a 15% reduction in the overall length of fair/poor and seriously polluted coastal waters by the end of 2000 and will aim to increase this to a 50% reduction by the end of 2005.

SEPA has proposed targets for protecting and enhancing Scotland's water environment based on its existing powers and resources. However, this Report has identified issues which will constrain the rate at which improvements can be achieved. This particularly applies to the protection of water resources and riparian or aquatic habitats. Additionally, this Report details SEPA's concerns over progress in controlling pollution from sewage effluent, diffuse agricultural sources, urban drainage and abandoned mines.



Introduction

Guidance was issued to SEPA by the Secretary of State for Scotland on its contribution to achieving sustainable development, guidance which SEPA incorporates into its everyday activities. SEPA will take an holistic approach to the environment and its functions, encourage new technologies and practices, work in partnership with all sectors of society and provide high quality information and advice. SEPA acknowledges that sustainable development is a real challenge, an important part of which is changing its attitude to the way it carries out its business. This is not unique to SEPA, it is a basic change which will be required of all organisations, whether public or private sector. The uncontrolled use of resources and production of pollution and wastes beyond the ability of the environment to absorb them cannot continue.


Scotland's water environment

The purpose of this Report is to develop the approach set out in SEPA's Environmental Strategy by setting targets for the improvement of Scotland's aquatic environment. This Report provides the people of Scotland with a clear view of how their environment protection agency proposes to improve and protect Scotland's water environment. The information on the water environment and the proposed actions which will be taken to improve it are presented at several levels of detail, ranging from a national summary, to data for individual bodies of water. The regional perspective provides information on local conditions and ensures that SEPA delivers a service which is sensitive to local concerns. Information on polluted waters is provided on SEPA's Website, giving wide public access to the actions proposed by SEPA to address pollution in individual rivers, lochs, estuaries and coastal waters.

This Report is divided into three main subject areas:

• State of the water environment
  In common with many European and North American environment agencies, SEPA considers that protecting the aquatic environment should take account of water quality, water quantity and habitat quality and the first section sets out the information available on these three aspects of the aquatic environment. As a result of the focus of the former river purification authorities and SEPA's other predecessor bodies, the Agency holds more information on water quality than on water quantity and habitat quality.
  
• Causes of pollution and pressures on the water environment
  The pressures on water quality, quantity and habitat quality are ranked in terms of the scale of damage caused. The major pressures influencing the state of the water environment are discussed together with the issues which will determine the rate at which SEPA can address these problems.
  
• Targets for improving the water environment
  SEPA is determined to set targets which are demanding, realistic, achievable and measurable. Targets for water quality improvements have been set at three levels: for Scotland, for each of the three SEPA Regions and for individual bodies of water. It has not been possible to provide targets relating to water quantity and habitat quality at the same level of detail. As a result, targets for water quantity and habitat quality relate mostly to the establishing of initiatives aimed at improving SEPA's understanding of their impact on the aquatic environment.

These targets take account of SEPA's duties to comply with EC Directives and duties defined under UK legislation to prevent, minimise, remedy or mitigate pollution. These targets must also have regard to the likely costs and benefits of the exercise of SEPA's powers as well as considering social and economic needs.

SEPA's statutory framework

SEPA is a non-governmental agency currently responsible to the Secretary of State for Scotland for providing a range of environmental protection services. SEPA came into being on 12 October 1995, and became fully operational on 1 April 1996 when it assumed the environmental regulatory functions previously carried out by its predecessor bodies. SEPA's capacity to describe, protect and improve the environment is determined by its powers and duties defined in statute. The main functions relating to the aquatic environment are described below. Virtually all matters relating to the environment are devolved to the Scottish Parliament to whom SEPA is accountable.

SEPA has duties to promote the cleanliness of inland waters, groundwaters and tidal waters and has powers to license discharges and to issue statutory notices. These powers must be used to either prevent, minimise, remedy or mitigate the effects of pollution on the environment.

The 1995 Environment Act which created SEPA, also defined a series of new duties:

• SEPA must compile information for the purpose of carrying out its pollution control functions relating to the general state of the environment.
• In formulating or considering any proposal relating to its functions, SEPA must have regard to the desirability of protecting, conserving and enhancing Scotland's natural heritage. Furthermore, SEPA has a duty, to such an extent as it considers desirable, to promote:
  • the conservation and enhancement of the natural beauty and amenity of inland and coastal waters and of land associated with such waters; and
  • the conservation of the flora and fauna which are dependent on an aquatic environment.
    
• SEPA has a duty in formulating or considering any proposals relating to any of its functions to have regard to the social and economic needs of an area and, in particular, to such needs of rural areas.
• In considering whether or not to use itspower under any enactment and in deciding the manner in which to exercise it, SEPA must normally take account of the likely costs and benefits of the exercise or non-exercise of its power.

The context for these duties is provided by guidance from the Secretary of State for Scotland which defines SEPA's principal aim:

'to provide an efficient and integrated environmental protection system for Scotland which will both improve the environment and contribute to the Government's goal of sustainable development'

SEPA delivers this national environmental protection service through three regions (East Region, North Region and West Region) and a Head Office in Stirling. The Agency Board members are appointed by the Secretary of State for Scotland and include individuals from local authorities, industry, agriculture, fish farming and non-governmental organisations (NGOs). Each SEPA Region has a Regional Board, appointed by the Agency Board, to ensure there is accountability and sensitivity to local concerns.


Measuring environmental quality

SEPA's view of aquatic environmental quality is formed from information collected by SEPA, other agencies, academic institutions and NGOs. The range of information available has increased progressively as concerns have moved beyond industrial and sewage pollution of the past to encompass other measures of environmental quality.

This change is reflected in the increasing scope of legislation relating to the water environment. Part II of the Control of Pollution Act 1974 and the Integrated Pollution Control regime introduced by the Environment Protection Act 1990 define SEPA's pollution control powers. This emphasis on pollution control has been widened by the 1995 Environment Act which includes general duties relating to natural heritage whilst the proposed EC Water Framework Directive² explicitly requires the monitoring and protection of ecological status, which includes consideration of water quality, water quantity and habitat quality.


Measurements of water quality

The quality of Scotland's waters was initially measured by chemical analysis. These analytical techniques measured the levels of oxygen demand and suspended solids which were used to assess the impact of sewage discharges and some forms of industrial pollution. Since the 1950s, the range of chemical measurements routinely carried out has increased considerably and now includes the measurement of nutrients, metals, oils and man-made organic substances such as pesticides and polychlorinated biphenyls. This expansion of analytical capability has significantly improved SEPA's understanding of threats to the water environment. However, there are difficulties in ensuring that a sufficiently wide range of parameters is measured and that an adequate number of water samples are taken to detect important changes and trends in water quality. The interpretation of chemical analyses also requires a good understanding of the concentrations above which a chemical causes damage to the environment, together with how it interacts with any other pollutants which may be present.

Biological sampling and analysis was introduced in the 1970s as an additional measurement of environmental quality. Where damage was identified, chemical analysis could then be used to determine the factors responsible. This combined approach has proved very successful, with the integrated measurement of environmental quality provided by biological sampling and analysis complementing the more focused chemical analysis techniques. In rivers, estuaries and coastal waters, the biological assessment of water quality has concentrated on the monitoring of benthic invertebrates (species of insects, crustaceans, snails and worms which live in the sediments). These species are sensitive to pollutants which cause oxygen levels in the water to drop or which are toxic. However, they are less efficient at monitoring the effects of elevated nutrients (eutrophication) and hormone disrupting chemicals. In coastal waters and freshwater lochs, macrophytes and algae have been used to assess the impact of eutrophication.

SEPA now also includes measurements of the aesthetic quality of bodies of water through the assessment of the quantity of litter in rivers, and litter and oil in estuaries and coastal waters.


Measurements of water quantity and habitat quality

Historically, biological sampling and chemical analysis have been used to assess the quality of water but the more recent concept of 'good environmental quality' has a wider meaning, in particular taking into account the quantity of water in a river or stream. Instances occur in Scotland where the abstraction of water from rivers has led to the river drying out downstream. SEPA and its predecessor bodies have measured river flows since the 1950s, allowing some of the more extreme examples of damage associated with abstractions to be identified. SEPA is developing methods for predicting the effect of water abstractions or flow regulation upon the flora and fauna of rivers and lochs.

Damage to the environment can also occur when the physical structure of river channels, loch shores and coastal beaches are modified by engineering or farming activity. The value of a river in terms of fishing, natural heritage and amenity/recreation is compromised if its natural diversity is removed by channel straightening, deepening or flood defence work. A method for assessing habitat quality has only recently been developed for rivers. This quantifies the damage to the structure of a river channel caused by flood defence, erosion control, drainage work and other changes of land use. Equivalent measures of habitat quality in lochs, estuaries and coastal waters have not yet been developed.


Historical improvements in water quality

Historical trends in pollution control provide the context within which to view SEPA's future proposals to improve water quality. They allow an assessment of how the rates of water quality improvement have changed as Scotland's rivers, estuaries and coastal waters have been cleaned up. Rates of improvement tend to decrease as remedial action is focused on those types of pollution which are most easily addressed by the legislation. The historical record also illustrates the importance of classification schemes which provide the means of identifying polluted waters consistently over time and which set baselines against which changes can be measured. Reviews of the classification schemes typically lead to significant increases in the amount of water defined as polluted as new measures of environmental quality are introduced.

Although flow records for rivers have been kept since the 1960s, no historical information is available on trends in water quantity impacts or damage to habitat quality. The classification schemes being developed now will provide the baseline from which future improvements can be monitored.


Water quality from 1800 to 1960

Historical records indicate that most of Scotland's rivers were in a clean and healthy condition at the beginning of the nineteenth century. However, the introduction of piped water supplies, together with the construction of sewers and the increasingly rapid growth of industry over the next six decades, resulted in widespread serious pollution of rivers, estuaries, coastal waters and groundwaters across not only Scotland but the whole of Britain. Parliament became so alarmed that a Royal Commission (The Rivers Pollution Commission) was set up in 1868. The Commission's report included a detailed account of the impact of pollution in four major Scottish river basins and made far sighted recommendations on the means to control water pollution.³

By the early 1900s, most rivers were grossly polluted downstream of significant conurbations, or below major concentrations of industry, such as active coal and oil-shale fields, iron and steel works and textile or paper mills. It is thought that most of the lower stretches of main rivers in the central belt were seriously polluted, with other local areas of gross pollution occurring around industrial coastal towns such as Dundee, Arbroath and Aberdeen.

In 1933, the Scottish Advisory Committee on Rivers Pollution Prevention reported that they considered the Rivers Leven and Ore, in Fife to be two of the most polluted rivers in Scotland.⁴

They reported that actions under the existing pollution control legislation had been largely ineffective at dealing with serious industrial and sewage pollution. In the catchments of the River Leven and Ore, the Committee recorded 53 discharges of largely untreated sewage, 18 collieries, of which 11 included coal washing facilities, four papermills, two bleachfields and one distillery. The two rivers were variously described as 'inky-black with coal washings', 'a public health nuisance', giving off 'strong and offensive smells', 'more the appearance of an open sewer than of a stream' and causing 'faeces to be frequently washed back by the tide onto the beach at Leven to the annoyance of holiday makers'.

Effective legislation to control new polluting discharges was not passed by Parliament until 1951, when a system of pollution regulatory authorities was set up comprising nine catchment based river purification authorities together with county and island councils in the north. These new regulatory authorities halted the deterioration in river water quality but it was not until The Rivers (Prevention of Pollution) (Scotland) Act was passed in 1965 that legislative means were provided to reverse the trend of the previous hundred years and begin the process of restoring Scotland's rivers to a healthy condition. Firstly, it provided for the control of existing discharges and secondly, laid the foundations for controlling discharges to tidal waters. With their new powers, the river purification authorities began developing long-term improvement programmes prioritising investment towards the reconstruction of existing wastewater treatment plants, the development of new sewerage systems and the building of new factory effluent treatment facilities.

The introduction of pollution control technology, in conjunction with the reduction in Scotland's heavy industries, resulted in major improvements in the quality of Scotland's waters. The current water pollution control legislation, The Control of Pollution Act, was introduced in 1974. It brought major innovations such as advertising applications for consent to discharge and the introduction of public registers. The Act also paved the way for the implementation of EC Directives which have played an important role in speeding up the process of environmental improvement.


Water quality from 1960

The large amount of data collected by SEPA and its predecessor bodies is summarised within four different water quality classification schemes designed to assess the degree of impact upon rivers, lochs, estuaries and coastal waters. The classification schemes differ in both the range of environmental variables included and in terms of the number of quality classes. Recently, the terms used to describe the categories have been harmonised and they now consist of combinations of excellent, good, fair, poor and seriously polluted.

This Report defines as 'polluted' any waters classified as fair, poor or seriously polluted. The classification schemes which SEPA currently uses are described in the section on the State of the Water Environment.

A river classification scheme was first introduced in 1968 by the Scottish Development Department.⁵ It was based primarily upon chemical measurements, although aspects of biological quality were also included. The first national surveys of water quality were carried out in 1968⁵ and 1974.⁶ It is difficult to compare these surveys with current results as the overall river length classified did not stabilise until the 1980 survey. Between 1969 and 1974 there was no evidence of any improvement and to the contrary, the polluted river length appeared to increase. In contrast, between 1974 and 1980⁷ , the length of poor and seriously polluted water fell despite the increase in river length classified.

Between 1980 and 1995, the length of polluted river in the fair, poor and seriously polluted categories decreased by 41% (see Figure 1).

In 1996, one of SEPA's first actions was to review the 30 year old river classification scheme to include a wider range of measurements of environmental quality including biological quality, nutrients and litter. This has increased the length of rivers classified as poor or seriously polluted by nearly five fold, whilst the river length in the fair category has doubled. It is recognised that it is no longer possible to make a direct comparison between current quality and that prior to 1996 but the new classification was necessary to reflect a wider view of what constitutes good quality in the aquatic environment.

The first national survey of loch water quality was undertaken in 1995 and further national surveys are not planned until the year 2000.

Classification results for tidal waters, covering estuaries and coastal waters, were also first produced in 1968. As with rivers, water quality did not appear to improve until after 1975. In 1990, new separate classification schemes were introduced covering estuaries and coastal waters and these demonstrate dramatic improvements in water quality over the five years to 1995 (see Figure 2 and Figure 3). The estuary classification scheme was revised in 1995, resulting in a larger area of estuarine waters being classified as polluted due to the inclusion of additional measures of environmental quality.


State of the Water Environment

This section reviews the available information on water quality, water quantity and habitat quality collected over the period 1995 to 1997. SEPA has defined the quality of the water environment in 1996, the year in which SEPA began its operations, as a baseline against which it can measure improvements up to the year 2000. The intention is to describe the scope of SEPA's monitoring regime and to review the information collected.

Information on surface water quality has been collected to support the water pollution control functions defined by legislation. Consequently, a substantial amount of information is available and the review of this data forms the bulk of the following section. Less detailed information is available on groundwater quality. SEPA, in common with its predecessor bodies, has limited powers relating to water quantity or habitat quality and consequently less information on these aspects of the environment has been collected.

This section identifies polluted waters in Scotland (defined as fair, poor or seriously polluted under SEPA's classification schemes). In particular, the water quality of rivers, lochs, estuaries and coastal waters during 1996 is described.


River and canal water quality

There are approximately 100,000 km of rivers in mainland Scotland as measured on the 1:50,000 scale map. SEPA currently classifies over 50,000 km of rivers. SEPA is developing a new means of defining the river and canal length which it will classify. This will be based upon a digitised 1:50,000 map where all rivers with catchment areas greater than 10 km² will be classified. SEPA takes invertebrate samples from 2,500 sites and chemical samples from over 2,100 sites across Scotland. Whilst this represents a good coverage for mainland Scotland, there are virtually no data for the Outer Hebrides, Orkney and Shetland. While many of these islands will have high quality waters, further work is needed to assess water quality on the more populated islands.


1996/97 river water quality

SEPA's river classification scheme, as applied to 1996 monitoring data, shows that about 91% of the classified river length was of excellent or good water quality (see Table 1). This left over 4,000 km which were classified as polluted (defined as fair, poor or seriously polluted).

Map 1 shows the distribution of sites which were classified as polluted during 1996. Most of the sites are located in Scotland's populated central lowlands, in urban, industrial and agricultural areas. The rivers in the highlands are typically of excellent or good quality. Because of the west to east drainage pattern across the highlands, the large east coast rivers maintain excellent or good water quality across the more populated east coast fringe. Typical examples are the Rivers Tay, Teith, Dee, Spey and Conon. The smaller east coast rivers with catchments within the coastal lowlands can be more seriously affected by agriculture and sewage/industrial discharges. Examples include the Rivers Ythan, Lunan and Eden. On the west coast, polluted waters are distributed from the Glasgow conurbation southwards into Ayrshire.


1996 canal water quality

There are nearly 200 km of canals in Scotland, of which the most important are the Forth and Clyde Canal and the Caledonian Canal which cross the central lowlands and Great Glen respectively. SEPA currently uses the river classification scheme to assess water quality in canals. Usually only the water chemistry parameters and the assessments of litter are used, as the biological aspects of the classification scheme are not designed for assessing the organisms found in canals. On this basis, 46 km of canals were classified as fair, 82 km as poor and 3 km as seriously polluted. Canals have been included within the river category for the remainder of the analysis presented in this Report.


Reasons why rivers were classified as polluted

Figure 4 identifies the main reasons why river stretches were classified as polluted. Damage to the invertebrate community resulted in 1,759 km of rivers being classified as polluted. Invertebrates are affected by a wide range of causes including pollution, changes to water flow and habitats. High biochemical oxygen demand, total reactive phosphorus and ammonia concentrations were related to sewage and industrial inputs, as well as run-off from agricultural land of organic wastes and inorganic fertilisers. A stretch of river may be classified as polluted for more than one reason.


Compliance with the EC Freshwater Fish Directive

The Scottish Office has designated 36,658 km of river as salmonid waters and a further 73 km as cyprinid waters (Forth and Clyde Canal) under the EC Freshwater Fish Directive (78/659/EEC). This Directive specifies chemical water quality standards which will ensure that the waters will continue to support healthy fisheries. In 1995, 95% of the designated waters complied with the required standards.


Loch water quality

Two measures of loch water quality will be considered in this section:

• 1995 loch water quality classification scheme; and
• prevalence of blue-green algal blooms.
  
  

Number of lochs in Scotland

There are 150 lochs in Scotland with a surface area above 1 km² and 3,788 lochs over 0.04 km² . Scottish Natural Heritage (SNH) has identified around 27,000 lochs large enough to feature on the Ordnance Survey 1:50,000 scale maps with a surface area greater than approximately 0.0001 km² .


1995 loch water quality

In 1995, SEPA's loch water quality classification scheme was applied to all 150 lochs over 1 km² together with 23 smaller lochs of particular local interest. The majority of lochs (143) were not significantly affected and were classified as excellent/good, but 27 were found to be significantly altered by human activity and classified as fair whilst three were either poor or seriously polluted (see Table 2). Map 2 shows the distribution of lochs throughout Scotland which were classified as being polluted (fair, poor or seriously polluted) in 1995.

SEPA recognises that the existing loch water quality classification scheme which is based solely upon chemical parameters has limitations and considers that biological information should eventually be included. SNH has developed a database which holds geographical, botanical and some water quality data for 3,207 lochs, representing nearly 12% of Scotland's lochs by number. SEPA and SNH are discussing how this valuable database might contribute to future monitoring programmes.


Reasons why lochs were classified as polluted

Of those lochs classified as fair quality, 20 (53 km² ) were affected by eutrophication and ten (57 km² ) by acidification (see Figure 5).

One of the lochs classified as being of fair quality was Loch Leven (Fife), a site of high nature conservation and fishery value. Although phosphorus concentrations have fallen in recent years, serious algal blooms are still recorded in this shallow lowland loch. On the basis of assessments of biological quality, Loch Leven is regarded by SEPA as verging on poor quality. Loch Grannoch (Dumfries and Galloway) was classified as poor quality because of the effects of acidification. Kilbirnie Loch (North Ayrshire) was classified as being of poor quality on the basis of elevated phosphorus concentrations, whilst Loch Gelly (Fife) was defined as seriously polluted because of high levels of ammonia (a dangerous substance included in List II of the EC Dangerous Substances Directive) and phosphorus concentrations caused by a discharge from a sewage treatment works. The sewage treatment works effluent was subsequently diverted from the loch in 1997.

Nutrient enriched lochs are distributed across lowland Scotland. Acidified waters are found mostly in the west where acidic inputs are high and the rocks of granitic origin produce soils with limited acid buffering capacity.


Blue-green algal blooms

Blue-green algae (Cyanobacteria) are a group of bacteria that have some of the characteristics of algae. They occur in a wide range of freshwater bodies and are potentially toxic. However, in nutrient enriched lochs there is a greater risk of the formation of blooms or scums in the watercolumn or mats of blue-green algae on the bottom of the loch.

In 1997, SEPA routinely monitored 77 lochs at risk of blue-green algal blooms. In 38 of these lochs, blue-green algal scums were noted, while an additional 20 lochs had sufficiently high levels of algae to indicate imminent formation of algal blooms (see Table 3).

Samples of loch water were collected from April to October, the time when blue-green algal blooms are most likely to occur. The results were reported to local authority environmental health departments. The lochs chosen for monitoring were those with a history of blooms, where the risk of people or animals coming into contact with high concentrations of blue-green algae was judged to be high. Since only high risk lochs were targeted, the occurrences of blue-green algal scums or concentrations in excess of the warning threshold levels are not necessarily representative of the total incidence of blooms across Scotland.


Estuarine water quality

The 1991 Nature Conservancy Council 'Estuaries Review' estimated that estuaries in Scotland occupied a total area of 1,352 km² in 49 estuaries.⁸ SEPA currently classifies 810 km² of estuarine waters in 32 estuaries.

The additional estuarine waters not covered by SEPA's classification scheme are mainly in the north-west highlands, the Hebrides, Orkney, Shetland and along the north coast of Scotland. The lack of major industrial developments or large population centres in these areas means that they are unlikely to be significantly affected by sewage or industrial pollution.


1996/97 estuarine water quality

In 1996, 96% of estuarine waters in Scotland were classified as being of excellent or good quality. Of the remaining 4% (31.8 km² ), almost all were classified as fair/poor, with only 1.5 km² classified as being seriously polluted (see Table 4).

In 1996, polluted estuarine waters were largely confined to those areas with the greatest population densities and highest concentrations of industrial development, with the majority in the Forth and Clyde estuaries and some associated tidal water tributaries (see Map 3). There were small areas of fair/poor or seriously polluted estuarine waters resulting from sewage related causes in the vicinity of Aberdeen and Inverness.


Reasons why estuarine waters were classified as polluted

In 1996, lack of dissolved oxygen resulted in 18 km² of estuarine waters being classified as polluted, with aesthetic impacts, mostly arising from sewage related litter, being the second most significant factor (see Figure 6). Environmental quality standards for substances listed in the EC Dangerous Substances Directive (76/464/EEC), primarily associated with run-off from timber yards, were exceeded in 3 km² of estuarine waters. The Ythan Estuary was classified as polluted due to changes in the resident flora and fauna as a result of nutrient enrichment. The excessive growth of green algae which formed dense mats over large areas of the estuary caused changes in the invertebrate communities living in the mud.


Coastal water quality

• Coastal water quality classification scheme; and
• Bathing water quality.
  
  

Coastal length in Scotland

SEPA's responsibilities for Scotland's marine waters extend up to three nautical miles from the coast. The Joint Nature Conservation Committee has calculated Scotland's mainland and islands coastline to be 11,800 km as measured on a 1:50,000 scale map. Over 6,900 km of Scotland's coastline is classified by SEPA. The existing SEPA network of sampling sites provides good coverage of the coastal waters close to the main urban and industrial areas of Scotland. The present scheme has not yet been applied to the coastal waters of the Outer Hebrides, Orkney and Shetland.

The scale of the marine fish farming industry in these islands emphasises the importance of incorporating the existing site specific monitoring of the industry into the coastal classification scheme.


1996/97 coastal water quality

SEPA's classification scheme defined 96% of coastal waters as excellent or good quality in 1996. Over 250 km of coastline were classified fair/poor or seriously polluted (see Table 5). Map 4 shows the distribution of coastal waters throughout Scotland which were classified as polluted in 1996.

SEPA produces comprehensive information on loadings of pollutants to tidal waters which are used to assess any local impacts on coastal waters, as well as being applied internationally in the assessment of impacts on the wider marine environment. The Scottish Office Agriculture, Environment and Fisheries Department (SOAEFD) has a broad role in the protection of the wider marine environment around Scotland. SEPA collaborates with The Scottish Office Marine Laboratory at Aberdeen in the collection, collation and reporting of marine environmental quality data as part of the UK's National Marine Monitoring Plan. An overview of the quality of the coastal water environment around Scotland was published in 1998 by SEPA and the Marine Laboratory.⁹


Reasons why coastal waters were classified as polluted

In 1996, aesthetic impacts from sewage and non-sewage related litter were the primary reasons why coastal waters were classified as polluted affecting 212 km of coastline (see Figure 7). Failure of bacteriological standards, primarily due to discharges of sewage, was the second most significant reason for stretches of coast being classified as fair/poor or seriously polluted. Biological impacts of sewage and fish farm discharges, chemical impacts of urban drainage, contaminated land and industrial effluents, all resulted in short stretches of coastline being classified as polluted. Waters around Skye (Loch Harport), Islay and Jura were classified as polluted due to chemicals in the form of traces of copper present in distillery effluent.


Bathing water quality

In 1998, SEPA monitored and reported on a range of microbiological, physical and chemical parameters at Scotland's 23 bathing waters identified under the EC Bathing Waters Directive. SEPA also monitored water quality at 93 additional coastal and inland sites. SEPA is concerned that water quality at the identified bathing waters has deteriorated recently and is working with the water authorities and other organisations to bring about improvements. In 1998, 12 bathing waters passed the mandatory bacteriological standards, compared with 18 in 1997, and 21 in 1996. The wet summer contributed to the poor results in 1998 by causing more frequent operation of combined sewer overflows and an increase in diffuse sources of pollution. More detailed information on the bacteriological quality of bathing and recreational waters has been published in SEPA's bathing water quality reports which are also available on SEPA's Website (see SEPA Contacts section). In 1998, SEPA adopted new policies on the initial dilution of discharges and microbiological standards in order to protect all bathing waters, recreational waters and foreshores visited by the public.

In early 1999, a review of Scotland's bathing waters resulted in the Secretary of State for Scotland identifying an additional 37 bathing waters. SEPA will therefore be monitoring a total of 60 EC identified bathing waters during the 1999 bathing season.


Geographical distribution of water quality

There are major differences in the water quality of the three SEPA Regions (see Figure 8, Figure 9, Figure 10 and Figure 11 ). These differences are attributable to the varying population density across Scotland (see Table 6) as well as other geographical factors such as the distribution of agricultural land and the topography of the country.

North Region includes some of the highest quality waters in Scotland which support important nature conservation, fishery and potable water resources.

Between 53% and 75% of the excellent quality rivers, lochs and coastal waters in Scotland are found in North Region. There are relatively few classified estuaries in North Region and these are predominantly of excellent quality.

West Region includes 53% of the Scottish total of polluted river length and the largest polluted coastal water length, 47% of the Scottish total. Most of the fair, poor or seriously polluted waters occur within the central lowlands and along the Ayrshire coast. In contrast, the southern uplands and the northern highlands, contain areas of excellent water quality.

East Region has many similarities with West Region with significant areas of polluted waters within the central lowlands and along the coastal fringe, whilst including areas of excellent quality waters especially to the north of the Highland Boundary Fault.

The total polluted river length in East Region is lower than that in West Region. However, there is a larger proportion of rivers classified in the poor or seriously polluted categories, 48% of the Scottish total. The length of coastline in East Region is relatively short but it includes a large proportion classified as polluted.


Groundwater quality

SEPA has not developed a groundwater quality classification scheme. A description of the available data on groundwater quality is provided below together with a brief assessment of future monitoring needs.

Groundwater is present in all areas of Scotland. However, the amount of water stored in the rock and its rate of flow varies. Certain types of sandstone can store water within the rock and are highly permeable, allowing relatively rapid water flow though the strata.

These aquifers can sustain high abstraction rates. In contrast, water storage and movement in rocks such as granite and conglomerates is highly dependent upon the degree of fissuring and jointing present and these rocks are typically less permeable and support low levels of abstraction.

Scotland's highest yielding aquifers are sandstone occurring in low-lying areas where the water table is at, or close to, ground level. The major hardrock aquifers lie within the area bounded by the Highland Boundary and Southern Uplands Faults, in coastal areas around the Moray Firth and Caithness, and in specific structures in the Scottish Borders and Dumfriesshire. As well as the hardrock aquifers, there are many locally important aquifers associated with superficial deposits in river gravels, glacial deposits and coastal sand dunes.


Sources of information

As a consequence of the dependence upon surface water resources for the supply of public drinking water, the strategic monitoring of groundwater resources has not been given a high priority. No strategic groundwater monitoring network exists which can give an overall assessment of groundwater quality. Regular groundwater monitoring is largely limited to site specific monitoring of landfill sites or contaminated land.

Any strategic assessment of groundwater quality in Scotland is therefore dependent upon the groundwater monitoring data required for public and private drinking water sources. About 97% of the population receives public potable water supplies, of which 3.5% originates from groundwater.¹¹ The quality of public water supplies, including groundwater sources, is monitored by the water authorities against drinking water standards defined by the EC Drinking Water Directive (80/778/EEC).

A large proportion of the 30,000 private water supplies is derived from boreholes or springs which utilise shallow aquifers. Private water supplies are sampled by local authority environmental health departments under the Private Water Supplies (Scotland) Regulations 1992.

The public drinking supplies do not provide a means of assessing overall groundwater quality as, by necessity, drinking water is extracted from aquifers which have high quality water.

Consequently, information is not available on the groundwater resources which are most threatened by urban and industrial development, for example, within the central lowlands. Despite these limitations, the monitoring of public supply sources provides the best available assessment of aquifer water quality in Scotland. Map 5 illustrates the levels of nitrate in public groundwater supplies and these data give an indication of the high quality of groundwaters used for public water supply. Only one of the 73 sources exceeds the 50 mg/l nitrate limit specified in the EC Nitrate Directive (91/676/EEC) and the EC Drinking Water Directive (80/778/EEC), with a further 11 boreholes exceeding the guideline value of 25 mg/l.

There are problems in the interpretation of monitoring results from private water supplies because samples are typically taken from the consumers' tap and not from the source. Work to collate the data from the 32 local authorities has only recently been initiated. However, because of the large numbers of samples, these data do have the potential to provide a valuable view of the water quality of shallow aquifers across Scotland. Shallow aquifers are potentially vulnerable to pollution associated with agricultural activity or urbanisation. Local authority data indicate excellent water quality throughout the highlands. However, in the lowlands the effects of intensive agricultural activity are detectable in the shallow springs and wells used for private supplies.


Improving groundwater monitoring

The British Geological Survey recently undertook a review of the requirements for groundwater quality monitoring on behalf of SEPA.¹² The report recommended the creation of 45 primary sites and 90 secondary sites for monitoring groundwater quality in the main productive aquifers. Information derived from the local authority data on private water supplies may assist in the identification of further monitoring sites outwith the area of the main aquifers.


Water quantity

The water resources of Scotland are subject to a wide range of uses, such as hydro-power generation, public water supply, industrial processes and agricultural irrigation. It is important to have information on the amount of water present in aquifers, rivers and lochs together with the seasonal and annual variation. An understanding of the variations in groundwater levels and flows in rivers is clearly linked to rainfall patterns and therefore, long-term rainfall data are needed to understand and to predict variations in the available water resources. This information is of importance for water resource management by the sectors which use large quantities of water and will influence the day-to-day management of their facilities and determine their strategic planning.

The amount of water in a river or flowing into a loch or estuary will determine the ability of waters to assimilate discharges of effluent. An understanding of the dilution provided by river flow to discharges is essential to allow SEPA to prevent the pollution of Scotland's surface waters.

The quantity of surface water and groundwater also has direct impacts upon Scotland's environment. Clearly, if all the water is removed from a river then the aquatic life will be destroyed. However, predicting how much water can safely be removed without affecting the ecology of a river is more difficult, as it depends upon an understanding of the habitat requirements of a wide range of fish, insects and plants. Similar problems exist in predicting the consequences of groundwater abstraction where over abstraction will reduce flow in rivers and cause wetlands to dry out. Aquatic flora and fauna have adapted to a natural range of variation in river flows or loch levels and damage can result if this range is significantly changed.

A water quantity monitoring strategy has to be based upon three levels of information. Firstly, information is needed on how much water is present and what variation is recorded seasonally and annually. Secondly, this information must be compared to natural conditions, to det#ermine the extent to which water abstraction and flow regulation (flow determined by the operation of reservoirs) has changed flow regimes in rivers or water levels in aquifers and lochs. Finally, an understanding must be developed to link changes from natural conditions to the risk of damage to the ecological quality of surface waters.

This section provides information on the current monitoring network and describes the available information on the environmental significance of changes in flow regimes. Most importantly, it highlights work currently underway to improve the monitoring of water quantity in Scotland.


Rainfall monitoring

Scotland has an abundance of rainfall over much of the mainland and the islands. Annual average precipitation exceeds 4,000 mm in parts of the west, falling to less than 600 mm along the east coast fringe. Seasonal differences in rainfall are relatively small as Scottish summers can be as wet as winters. However, there is a large year-to-year variation in rainfall, especially between wet and dry summers. This geographical and annual variation in rainfall is expected to be exacerbated with the predicted effects of climate change. Current trends suggest more frequent dry east coast summers, whilst in the west, rainfall is expected to increase overall.

SEPA operates a network of over 400 rain gauges including both volumetric and automatic logging types. All SEPA rainfall data is forwarded to the Meteorological Office and makes a substantial contribution to the national rainfall database.


Groundwater monitoring

To manage groundwater resources in a sustainable manner it is necessary to monitor trends in aquifer water levels. This identifies those aquifers where over abstraction results in a consistent fall in water levels. Apart from the long-term risk to the viability of the resource, there are serious environmental hazards associated with lowering groundwater levels. For example, poor quality water can be drawn into the aquifer from surface layers or from saline coastal aquifers. In addition, groundwater provides much of the river flow during dry weather and a fall in groundwater levels can lead to reductions in river flows and the drying out of wetlands. One of the best documented instances of such over exploitation of a groundwater resource is in the Dumfries Aquifer. Increasing abstraction of water from this aquifer has lowered the water table and resulted in reduced flows in the Wolfgill Burn and more recently, small watercourses in the Calside area of Dumfries. Industrial users and West of Scotland Water Authority have abstracted from this aquifer for many years, although the largest single abstractor is a fish farm.

Information on groundwater levels is sparse. SEPA currently monitors groundwater levels in 19 boreholes (see Map 6).

Continuous monitoring data have been available for the Dumfries Aquifer since the early 1980s. In the east of Scotland, continuous level recorders have been installed in the Polkemmet, Monktonhall and Frances/Michael mining complexes to record groundwater rebound following abandonment. It is important to monitor water levels in abandoned mines as there is the potential for polluted mine water levels to rise and contaminate surface waters.

The British Geological Survey report which assessed the groundwater monitoring requirements for Scotland proposed a total of 70 groundwater level monitoring sites covering highly permeable aquifers.12 In moderately permeable aquifers 90 sites were recommended, whilst for weakly permeable aquifers a further 30 sites were proposed. This scale of monitoring would enable SEPA to effectively monitor groundwater levels and provide the basis for ensuring that abstraction did not threaten the long-term use of the water resource or pose a threat to surface water resources.


River flow monitoring

SEPA's predecessor bodies, the river purification authorities, concentrated on measuring the surface water resources of Scotland to provide information of strategic importance on water resources, for flood warning purposes and to support their core business of pollution control.

There are 311 primary gauging stations in Scotland which monitor flows continuously (see Map 6). These are mostly near the mouths of large river systems and are estimated to monitor run-off from just over 50% of the mainland area. In addition, there are approximately 300 secondary sites where flows are measured on a regular basis. The collection of river flow data is just starting in the islands, where virtually no flow information existed prior to the creation of SEPA.


Abstractions

It has only been possible to quantify the extent to which river flows were affected by either abstraction, flow transfer or regulation in a small number of catchments where flow measurement existed prior to the construction of a reservoir or the development of a new abstraction.

However, many of Scotland's larger rivers do not appear to be seriously affected by abstractions, although examples of stretches subject to the abstraction of a significant proportion of the river flow do exist. These are primarily associated with the removal of water for hydro-power generation, industrial cooling water and fish farming where the water is returned at some point downstream. Levels of abstraction which have the potential to cause environmental damage have also been recorded in the small/medium sized water courses along the east coast used for agricultural irrigation, especially in the Lower Tweed catchment, East Lothian, Fife, around Perth and Dundee, and Aberdeenshire.


Flow regulation

The natural variation in water levels and flows has been substantially changed throughout Scotland by the hydro-electricity generation sector and water supply reservoirs. For example, the effects of flow regulation caused by hydro-power are evident throughout the length of the Rivers Tay, Conon, Beauly and Ness.

There are some circumstances where flow regulation by hydro-electricity schemes and water supply dams may lead to environmental benefits by limiting the effects of floods and supplementing flows during periods of extreme low rainfall. However, there are also examples of where damage to the ecological and amenity value of rivers has resulted. The scale at which environmental damage occurs nationally is difficult to assess but it is probably limited to a relatively low proportion of the river length affected. However, there are examples of where clear damage to the ecological and amenity value of rivers has resulted. For example, the River Devon in Clackmannanshire has four drinking water reservoirs in its headwaters. Stable compensation flows from these reservoirs frequently lead to the accumulation of silt and algae on the river bed in the summer, followed by complaints about the appearance of the river and the condition of the fishery. Anglers have also complained about the stranding of migratory salmonids in the River Leven, West Dunbartonshire. These strandings result from the rapid change between high and low flow conditions associated with the operation of the barrage which controls levels in Scotland's largest public water source, Loch Lomond. Similar difficulties can occur downstream of hydro-electricity schemes where alternating high and low flow regimes produce a bare zone along the river bank which is unsuitable for aquatic or terrestrial animals and plants.


Improving the assessment of water quantity impacts

In recognition of the need to assess impacts on the water resources of Scotland, SEPA has already developed modelling capability to predict natural river flows. This will allow a more objective means of assessing the scale of any changes from natural river flows. In addition, SEPA has initiated a research project funded by the Scotland and Northern Ireland Forum For Environmental Research (SNIFFER) to develop a methodology which will classify hydrological changes in terms of the scale and severity of any ecological impacts. The project will be complete by the end of 1999.

Habitat quality

Indirect impacts result from land management practices such as grazing, ploughing or the application of herbicides.


Measuring the quality of river habitats

River Habitat Survey (RHS) methodology was developed to allow a consistent description of habitat quality in river channels and riparian areas across the UK. Equivalent methodologies are not yet available to assess the condition of habitats associated with lochs or tidal waters.

A report, River Habitat Quality¹³ , presented for the first time a UK wide view of the habitat and physical quality of river channels. The report is based upon an extensive survey of sites throughout the UK, including 779 reference sites in Scotland. The survey of Scottish sites was undertaken between 1995 and 1997 and involved the assessment of one 500 m river reach, chosen at random from within each 10 km by 10 km square. The strength of the database is that, as it includes data from over 5,000 sites located throughout the UK, it enables Scottish sites to be placed in a UK context. Data from future RHS surveys will be added to this UK database on a regular basis.


1995/97 river habitat quality

Map 7 shows sites across Scotland where river habitats have been modified. The RHS data reveal that just under 50% of the sites visited in Scotland were classified as semi-natural, 23% were classified as predominantly unmodified, while 28% of sites were classified as either obviously modified, extensively modified or heavily modified (see Table 7). SEPA North Region has the largest proportion of semi-natural sites at 54% and the lowest proportion of extensively modified and heavily modified sites at 11%. The geographical distribution of modified sites reflects the impacts of agriculture and urban development.


Measuring the quality of coastal and estuarine habitats

Although there is currently no quantitative method, equivalent to RHS, for the assessment of habitat quality in lochs, estuaries or along coastlines, there is evidence of extensive modification of habitats in some of Scotland's estuaries.

The 1991 Nature Conservancy Council 'Estuaries Review'⁸ reported that extensive lengths of shore in many estuaries have been constrained within embankments to reduce the risk of flooding on adjacent land, often accompanied by the loss of marsh habitats. In addition, significant loss of intertidal habitats through land claim has taken place in a number of sites, for agricultural, housing, port and industrial developments. These losses have been quantified for only two estuaries, the Forth where 49% of the pre-industrial intertidal area has been claimed and Hunterston Sands, on the Firth of Clyde, where 37% of the intertidal area has been lost due to industrial developments since the 1970s. Although not quantified, habitat losses in other estuaries, such as the Clyde, have also been extensive. The effects of intertidal habitat loss in estuaries are varied, ranging from impacts on bird and fish populations which use these habitats for feeding, to a reduction in shallow water areas which play a part in the mixing and oxygenation of estuarine waters.

Part 2 of the Report