Key Scottish Environment Statistics 2016

Water

Background

Water is vitally important for a number of areas as it supports a variety of wildlife, is an important resource for tourism and recreation and provides domestic and commercial water supplies. Water quality can be negatively affected by the enrichment of nutrients such as nitrates and orthophosphates, which can affect aquatic ecosystem health, and by the presence of certain bacteria that can pose a potential risk to public health.

Water body type	Approximate area/length (to the nearest thousand)	Additional information
Rivers	125,000 km	There are also 220 km of canals in Scotland
Lochs	2,000 km 2	There are 25,500 lochs in Scotland - over 17,600 of these cover less than 0.01 km 2.
Estuaries	1,000 km 2	There are 49 estuaries in Scotland assessed through the Water Framework Directive, including 9 salt-water lagoons.
Coastal Waters	48,000 km 2	Scotland has approximately 19,000 km of coastline
Offshore Waters	462,000 km 2	Scottish offshore waters extend from 3 nautical miles from the coast to the Exclusive Economic Zone ( EEL).

Maintaining water health
Maintaining the health of Scotland's water bodies is important for protecting drinking water supplies and wildlife, and for industries such as tourism, aquaculture and whisky production.

There are a number of pressures on the health of Scotland's water bodies including rural diffuse pollution, waste water and hydropower generation. Rural diffuse pollution can occur when rainwater run-off from land picks up soil, fertilisers and pesticides used in agriculture, forestry and other rural land uses, which can in turn result in eutrophication ^[68] . Scottish Environment Protection Agency ( SEPA) has an extensive monitoring network, which focusses on high priority areas, to monitor the general health of Scotland's water bodies and to help target action when required.

Scottish Water is the body responsible for public water supplies and for monitoring the quality of drinking water that it supplies.

Targets and Indicators
SEPA compile a long-term river water quality indicator based on five parameters (see page 34). There are also various standards to be met for:

• The quality of Scottish bathing waters - set out in the EC Bathing Water Directive (76/160/ EEC). These have now been superseded by the EU Bathing Water Directive (2006/7/ EC).
• The quality of drinking water - set out in the Water Supply (Water Quality) (Scotland) Regulations 2001 ^[69] . These have now been superseded by the Public Water Supplies (Scotland) Regulations 2014.

Public Water Supplies - Water Abstracted and Supplied: 2002/03-2015/16 ^[70,71]

Million litres per day (Ml/d)

Why this measure is important
For sustainable management of water resources, it is essential to meet consumer demand whilst maintaining aquatic ecosystem health. The abstraction of water can have impacts on geology, habitats, wildlife and biodiversity.

Background
Water abstraction is managed by Scottish Water and Scottish Environment Protection Agency under the Water Resource Planning and River Basin Management Planning Processes.

Trend
Between 2002 and 2009, estimated raw water abstractions by Scottish Water decreased by 13% to 2,165 Ml/d. Between 2010 and 2015, using improved data and methodology, the volume of raw water abstracted also decreased by 12.6% to 1,831 Ml/d. Between 2004/05 and 2015/16, treated water produced fell by 598 Ml/d (25%) to a new low of 1,780 Ml/d. There has been a slight increase of 89 Ml/d (13%) in domestic water consumption between 2004/05 and 2015/16, while non-domestic water consumption has decreased by 98 Ml/d (19%) over the same period. However, there has been relatively little change in all water consumption overall (domestic, non-domestic and operational use ^[72] ) between 2004/05 and 2015/16.

Factors affecting trend
The decrease in treated water is almost entirely due to a reduction in leakage ^[73,74] of 608 Ml/d (53%) between 2004/05 and 2015/16. The increase in domestic water consumption partly reflects an increase in the number of households and the decrease in non-domestic water consumption partly reflects the introduction of the retail market, where retailers offer customers advice on how to reduce their water and sewerage bills.

Source: Scottish Water
Metadata

Drinking Water Quality: 1992-2015

Percentage of samples at consumers' taps containing coliform bacteria

Why this measure is important
The coliform group of bacteria is present in the gut of all warm-blooded animals and is widely distributed in the environment. Their presence in tap water indicates a breach in the integrity of the water supply system.

Background
Scottish Water is required to analyse samples taken from water treatment works, service reservoirs and consumers' taps to test for the presence of coliform bacteria. Samples containing coliform bacteria fail to meet the standards set out in the Water Supply (Water Quality) (Scotland) Regulations 2001 ^[75] . These regulations have now been superseded by the Public Water Supplies (Scotland) Regulations 2014, which sets out the standards to be met by the 2015 tests. The Drinking Water Quality Regulator for Scotland publishes an annual report summarising this data ^[76] .

Trend
Between 1992 and 2015, the percentage of samples from consumer taps containing coliform bacteria fell from 4.64% to 0.25% and the percentage containing Escherichia coli ( E. coli) fell from 2.08% to 0.01%. Between 2014 and 2015, the failure rate for total coliforms decreased by 0.20 percentage points to the lowest level recorded, while the failure rate for E. coli remained fairly constant.

Factors affecting trend
Most of this overall improvement is the result of investments made at water treatment works across the country over the past ten years. In recent years, many improvements have been made to most of the small, rural treatment works that have historically been unable to consistently and satisfactorily treat water to the standard required by the Regulations.

Source: Drinking Water Quality Regulator For Scotland
Metadata

River Water Quality: 1992-2015

Distribution of river water quality, percentage of river length within each band

Why this measure is important
Low standards of river water quality may threaten the aquatic environment, drinking water quality and impact on recreational water use. River water quality can be affected by a number of factors including sewage, industry, urban development and agriculture.

Background
The Scottish Environment Protection Agency ( SEPA) long term indicator of river water quality is based on a network of sites covering 253 water bodies (rivers or sections of rivers), which account for approximately 10% of all water bodies in Scotland. Two of the standards used to calculate the indicator were changed in 2013 ^[77] . In this indicator, river water quality is classified as 'unimpacted by pollution,' 'unpolluted', 'slightly polluted', 'polluted', or 'severely polluted'. The 'polluted' and 'severely polluted' categories have been combined on the chart above so that they can be seen more clearly.

Trend
The proportion of river length that was classed as slightly polluted, polluted or severely polluted in Scotland rose from 6.8% in 1992, to 7.4% in 1998, before falling to 3.4% in 2013, using the old standards. Using the new standards, this proportion fell from 3.7% in 2013 to 3.5% in 2015. The proportion of river length classed as unpolluted fell from 86.5% in 2010 to 84.8% in 2013. Using the new standards, the proportion of river length classed as unpolluted rose slightly from 83.3% in 2013 to 84.0% in 2015. In 2015, the proportion of river length classed as unimpacted by pollution was 12.5%.

Factors affecting this trend
The main drivers of slightly polluted, polluted and severely polluted rivers are inputs of nutrients, such as those from agriculture and waste water treatment works, leading to degraded biological and nutrient quality. In general, Scottish water quality has improved following the investments made to the sewage infrastructure in Scotland.

Source: Scottish Environment Protection Agency
Metadata

Nitrate Concentrations in Rivers: 2000-2015

Distribution of mean nitrate concentrations, percentage of sites ^[78] within each band

Why this measure is important
The enrichment of waters by nutrients, such as nitrates, may lead to the damage of the aquatic environment through eutrophication. Therefore, monitoring of the water environment for nutrient enrichment is important to protect water quality. Although some freshwater lochs can be at risk, high nitrate levels tend to have a greater impact on marine and coastal waters than on freshwater.

Background
The chart above is based on concentrations at the 153 sites where four or more samples per year have been taken each year since 2000, to provide a consistent time series.

Trend
Nitrate concentrations below 0.3 mg N/l are considered to be natural or background levels ^[79] ; the percentage of sites with mean nitrate concentrations of less than 0.3 mg N/l has increased from 27% in 2000 to 34% in 2015. In 2015, less than 3% of sites had nitrate concentrations greater than or equal to 7.5 mg/l compared with over 7% of sites in 2000.

Factors affecting trend
The main source of nitrates in freshwater is from agriculture; nutrients are important for crop growth and good nutrient management is crucial to ensure there is no excessive loss to the water environment. Currently, 10% of the area of Scotland ^[80] is designated, through legislation, as Nitrate Vulnerable Zones ( NVZs) ^[81] , in which mandatory rules on farming practices aim to reduce nitrate water pollution from agricultural sources.

Source: Scottish Environment Protection Agency
Metadata

Orthophosphate Concentrations in Rivers: 2000-2015

Distribution of mean orthophosphate concentrations ^[82] , percentage of sites in each band

Why this measure is important

Raised levels of orthophosphate in freshwaters may lead to eutrophication. The main source of phosphorus is diffuse pollution from agriculture, but discharges from waste water treatment works and septic tanks also contain phosphates.

Background
The chart above is based on concentrations at the 145 sites where four or more samples per year have been taken each year since 2000, to provide a consistent time series.

Trend
The percentage of sites with orthophosphate concentrations less than 30 μg P/l has generally increased over time from 44% in 2000 to 73% in 2013 before falling to 63% in 2015. The percentage of sites with concentrations greater than or equal to 125 μg P/l has generally fallen over this period.

Factors affecting trend
These changes mainly reflect the improvements in water quality following the investments made to the sewage infrastructure in Scotland. Under the Urban Waste Water Treatment Directive (91/271/ EEC), catchments where nutrient levels are considered to be high are designated as sensitive areas. Discharges into waters that have been designated as sensitive require additional treatment to remove nutrients.

Source: Scottish Environment Protection Agency
Metadata

Coastal Bathing Water ^[83] Quality 2000-2016

Why this measure is important
There is a potential risk to public health if high concentrations of faecal bacteria are present in bathing waters. This can occur if heavy rain leads to increased surface water run-off in urban areas and fields, which causes contaminants to enter the water.

Background
EC Bathing Water Directive (76/160/ EEC) set out requirements for Member States to monitor and assess the water quality at designated bathing waters, and provide public information on the results. The Directive set out two quality standards - the 'mandatory' standard and the stricter 'guideline' standard. Designated bathing waters should comply, as a minimum, with the mandatory standard and aim to comply with the guideline standard. Since 2015, bathing water has been assessed by new tighter standards on bathing water quality based on four years performance, as set out in EU Bathing Water Directive (2006/7/ EC).

Trend
In 2014, all but two of Scotland's coastal bathing waters met the mandatory standard, with 56% of the bathing waters also achieving the guideline standard. There was a steady improvement in compliance with the mandatory standard between 2007 and 2013 when all coastal bathing waters met the mandatory standard. On the basis of initial assessments for 2016, 85% of the 81 coastal bathing waters met the new minimum European standard with 73% classified as excellent or good quality. There has been an increase in the number of coastal bathing waters assessed as excellent quality from 16 over the four years to 2015 to 25 over the four years to 2016. The number assessed as poor quality fell from 17 over the four years to 2015 to 12 over the four years to 2016.

Factors affecting trend
Weather can have a large effect on the compliance of bathing waters, as heavy rain can lead to overflows from drains and surface water run-off from fields containing animal manure, which raises the risk of sites failing to meet the required standard.

Source: Scottish Environment Protection Agency
Metadata