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2. Implications of the proposals
Water quality (see page A2)
SEPA's existing classification schemes are based on standards for water quality, including all of the proposed elements except salinity. The new proposals are similar to these existing standards, but more closely matched to the natural variations in ecology in that they are type-specific: different thresholds are set for different types of river or loch. Existing standards do not differentiate between river or loch types.
The key differences from existing standards are for:
- Ammonia (rivers): two different river standards are proposed in place of the single existing ammonia standard (see typology in Annex A). A more stringent standard is proposed for upland (above 80m), low alkalinity rivers, although there is no change for lowland, high alkalinity rivers. Available monitoring information indicates that in Scotland, an additional 200km river length (~ 0.8% of the 25,000km monitored length) would be defined as at risk of failing the proposed standards.
- Phosphorus (rivers): the proposals define standards for three types of rivers instead of the single existing standard (see typology in Annex A). More stringent standards are proposed in low alkalinity rivers, but a less stringent standard is proposed in high alkalinity rivers. Available monitoring information indicates that the distribution of 'at risk' length would change to focus primarily on low alkalinity rivers. However, overall, very little additional river length (~30km: under 0.1% of the monitored length) would be defined as at risk. This would mean better targeting of resources to those water bodies where the ecology is judged to be most at risk from raised nutrient levels.
- Oxygen levels (rivers): the proposals define dissolved oxygen ( DO) and biochemical oxygen demand ( BOD) standards for two types of rivers (see typology in Annex A). For upland, low alkalinity rivers, the proposed DO standard is more stringent than the existing standard. However, the impact of this change is expected to be minimal overall as the proposed BOD standard, which SEPA uses to determine whether action is needed, is not altered by the proposals. In lowland, high alkalinity rivers, the proposals slightly relax both BOD and DO standards. Available monitoring information indicates that in Scotland the overall length of river at risk of failing the standard would decrease slightly.
- Salinity (freshwater lochs): A standard is proposed for salinity, in line with the Directive's requirements (see Annex A). No standard has previously existed in Scotland. However, SEPA considers it highly unlikely that any lochs in Scotland would be at risk of failing this standard. Therefore, the proposed standard is unlikely to have any significant implications for Scotland, or drive action in the foreseeable future.
Water resources (see page A12):
Until CAR was introduced, Scotland had no comprehensive controls for abstractions or activities that alter water flow. The standards proposed in this paper are therefore new in Scotland. They aim to protect ecology from extremely low flows by restricting the permitted changes from natural flow patterns (see example at the end of this section). The standards are similar to the risk criteria used in the 'Article 5' risk assessments, so no significant changes are anticipated in the number of water bodies predicted to be at risk in Scotland.
Morphology (page A17):
Engineering or construction works in freshwater have only become regulated in Scotland this year, with the introduction of CAR. A new decision-supporting framework is proposed here, as a tool to support the initial assessment of new applications for engineering or construction works in rivers. This is the first framework of its kind to be introduced in the UK. It aims to enable all decisions about new applications for such works in rivers to be made on a consistent basis. It will provide a consistent mechanism to identify the relatively low-impact proposals that could be carried out without compromising the ecology of the water body. An additional detailed assessment will still be required for all applications that would have a significant impact on the water body morphology. This additional assessment will inform the selection of measures to minimise harm to the environment and to promote efficient and sustainable use of the remaining capacity.
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