# The Water Framework Directive (Classification, Priority Substances and Shellfish Waters) Regulations (Northern Ireland) 2015, Paragraph 7

Extent: N.I.

To determine the morphological conditions applicable to a lake or any part thereof, the Department must assign the hydromorphological characteristics of the lake or part thereof as being of the type specified in column 1 of Table 9 below which corresponds to the applicable measurements specified in columns 3 and 4 of that Table.
Table 1
Criteria for identifying the types of river to which the dissolved oxygen, ammonia and biochemical oxygen demand standards for rivers apply
Site Altitude
Alkalinity (as mg/l CaCO3)
Less than 10
10 to 50
50 to 100
100 to 200
Over 200
Under 80 metres
Type 1
Type 2
Type 3
Type 5
Type 7
Over 80 metres
Type 4
Type 6
Table 2
Final typology for dissolved oxygen, ammonia and biochemical oxygen demand in rivers
Column 1
Column 2
Upland and low alkalinity
Types (1+2), 4 and 6
Lowland and high alkalinity
Types 3, 5 and 7
Table 3
Criteria for identifying types of river to which morphological conditions apply
Type
Characteristics
Bedrock channel
Normally high altitude
Channel cuts down laterally
May have waterfalls and/or cascades
Bedrock substrate
Cascade Step Pool
Normally high altitude
Channel cuts down
Both turbulent and tranquil flows
Cobble and boulder substrate
Pool-riffle-glide
Normally medium altitude
Often not confined within a valley
Slightly meandering
Pebble and cobble substrate
Meandering
Normally low altitude
Flow laminar and would naturally interact with floodplain
Meandering
More fines than other substrates
Table 4
Criteria for identifying types of river to which the river flow standards apply
Column 1
Column 2
Column 3
Column 4
Type
Standard Average Annual Rainfall mm (period 1961-1990)
Base Flow Index (BFI)
Catchment area (km2)
A1
< 810.5
< 0.715
Any
≥ 0.715
≥ 251.8
A2
< 810.5
≥ 0.715
< 251.8
≤ 100 (A2 headwaters)
> 100 (A2 downstream)
≥ 810.5 and < 1413
≥ 0.7495
Any
≤ 100 (A2 headwaters)
> 100 (A2 downstream)
B1
≥ 810.5 and < 1155
≥ 0.3615 and < 0.7495
< 267.4
B2
≥ 810.5 and < 1413
≥ 0.3615 and < 0.7495
< 267.4
C2
≥ 1155 and < 1413
≥ 0.3615 and < 0.7495
< 267.4
≥ 1413
≥ 0.3615
≥ 32.33
D2
≥ 1413
≥ 0.3615
< 32.33
≥ 810.5
< 0.3615
Any
Table 5
Geological categories to which total phosphorus, phytoplankton and phytobenthos standards for lakes apply
Geological category
Annual mean alkalinity (micro-equivalents per litre)
Low alkalinity
< 200
Moderate alkalinity
200 – 1000
High alkalinity
> 1000
Marl
Table 6
Depth categories to which total phosphorus standards for lakes apply
Depth category
Mean depth (metres)
Very shallow
< 3
Shallow
3 – 15
Deep
> 15
Table 7
Colour categories to which total phosphorus standards for lakes apply
Colour category
Platinum (mg/l)
Humic
> 30
Non humic
≤ 30
Table 8
Geological characteristics used to identify lake types to which lake level standards apply
Categories
Column 1
Column 2
Peat
Non-Peat
mean water colour ≥90 hazen units; or
mean water colour <90 hazen units; or
≥75% of solid catchment area comprised of peat
<75% of solid catchment area comprised of peat
Table 9
Hydromorphological characteristics used to identify lake types to which morphological conditions apply
1 Morphological Impact Assessment System
Column 1
Column 2
Column 3
Column 4
Type
Lake-MImAS1 code
Mean Depth
Alkalinity
Low Alkalinity
Very Shallow
P/L-vS
<4m
< 20 mgl-1 CaCO3
Low Alkalinity Shallow/Deep
P/L-ShD
>4m
< 20 mgl-1 CaCO3
Moderate Alkalinity Very Shallow
MA-vS
<4m
20 – 100 mgl-1 CaCO3
Moderate Alkalinity Shallow/Deep
MA-ShD
>4m
20 – 100 mgl-1 CaCO3
High Alkalinity Very Shallow
HA/M-vS
<4m
> 100 mgl-1 CaCO3
High Alkalinity Shallow/Deep
HA/M-ShD
>4m
> 100 mgl-1 CaCO3

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Source: https://www.legislation.gov.uk/nisr/2015/351/schedule/1/part/1/paragraph/7 (the official version)
Page: https://openlegislation.uk/water-framework-directive-classification-priority-substances-and-shellfish-waters-regulations-northern-ireland-2015/schedule-1/part-1/paragraph-7
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.