{
  "url": "https://openlegislation.uk/water-framework-directive-classification-priority-substances-and-shellfish-waters-regulations-northern-ireland-2015/schedule-1/part-1/paragraph-7",
  "json_url": "https://openlegislation.uk/water-framework-directive-classification-priority-substances-and-shellfish-waters-regulations-northern-ireland-2015/schedule-1/part-1/paragraph-7.json",
  "legislation": "nisr/2015/351",
  "legislation_title": "The Water Framework Directive (Classification, Priority Substances and Shellfish Waters) Regulations (Northern Ireland) 2015",
  "legislation_url": "https://openlegislation.uk/water-framework-directive-classification-priority-substances-and-shellfish-waters-regulations-northern-ireland-2015",
  "path": "schedule/1/part/1/paragraph/7",
  "kind": "paragraph",
  "number": "7",
  "heading": null,
  "text": "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.\nTable 1\nCriteria for identifying the types of river to which the dissolved oxygen, ammonia and biochemical oxygen demand standards for rivers apply\nSite Altitude\nAlkalinity (as mg/l CaCO3)\nLess than 10\n10 to 50\n50 to 100\n100 to 200\nOver 200\nUnder 80 metres\nType 1\nType 2\nType 3\nType 5\nType 7\nOver 80 metres\nType 4\nType 6\nTable 2\nFinal typology for dissolved oxygen, ammonia and biochemical oxygen demand in rivers\nColumn 1\nColumn 2\nUpland and low alkalinity\nTypes (1+2), 4 and 6\nLowland and high alkalinity\nTypes 3, 5 and 7\nTable 3\nCriteria for identifying types of river to which morphological conditions apply\nType\nCharacteristics\nBedrock channel\nNormally high altitude\nChannel cuts down laterally\nMay have waterfalls and/or cascades\nBedrock substrate\nCascade Step Pool\nNormally high altitude\nChannel cuts down\nBoth turbulent and tranquil flows\nCobble and boulder substrate\nPool-riffle-glide\nNormally medium altitude\nOften not confined within a valley\nSlightly meandering\nPebble and cobble substrate\nMeandering\nNormally low altitude\nFlow laminar and would naturally interact with floodplain\nMeandering\nMore fines than other substrates\nTable 4\nCriteria for identifying types of river to which the river flow standards apply\nColumn 1\nColumn 2\nColumn 3\nColumn 4\nType\nStandard Average Annual Rainfall mm (period 1961-1990)\nBase Flow Index (BFI)\nCatchment area (km2)\nA1\n< 810.5\n< 0.715\nAny\n≥ 0.715\n≥ 251.8\nA2\n< 810.5\n≥ 0.715\n< 251.8\n≤ 100 (A2 headwaters)\n> 100 (A2 downstream)\n≥ 810.5 and < 1413\n≥ 0.7495\nAny\n≤ 100 (A2 headwaters)\n> 100 (A2 downstream)\nB1\n≥ 810.5 and < 1155\n≥ 0.3615 and < 0.7495\n< 267.4\nB2\n≥ 810.5 and < 1413\n≥ 0.3615 and < 0.7495\n< 267.4\nC2\n≥ 1155 and < 1413\n≥ 0.3615 and < 0.7495\n< 267.4\n≥ 1413\n≥ 0.3615\n≥ 32.33\nD2\n≥ 1413\n≥ 0.3615\n< 32.33\n≥ 810.5\n< 0.3615\nAny\nTable 5\nGeological categories to which total phosphorus, phytoplankton and phytobenthos standards for lakes apply\nGeological category\nAnnual mean alkalinity (micro-equivalents per litre)\nLow alkalinity\n< 200\nModerate alkalinity\n200 – 1000\nHigh alkalinity\n> 1000\nMarl\nTable 6\nDepth categories to which total phosphorus standards for lakes apply\nDepth category\nMean depth (metres)\nVery shallow\n< 3\nShallow\n3 – 15\nDeep\n> 15\nTable 7\nColour categories to which total phosphorus standards for lakes apply\nColour category\nPlatinum (mg/l)\nHumic\n> 30\nNon humic\n≤ 30\nTable 8\nGeological characteristics used to identify lake types to which lake level standards apply\nCategories\nColumn 1\nColumn 2\nPeat\nNon-Peat\nmean water colour ≥90 hazen units; or\nmean water colour <90 hazen units; or\n≥75% of solid catchment area comprised of peat\n<75% of solid catchment area comprised of peat\nTable 9\nHydromorphological characteristics used to identify lake types to which morphological conditions apply\n1 Morphological Impact Assessment System\nColumn 1\nColumn 2\nColumn 3\nColumn 4\nType\nLake-MImAS1 code\nMean Depth\nAlkalinity\nLow Alkalinity\nVery Shallow\nP/L-vS\n<4m\n< 20 mgl-1 CaCO3\nLow Alkalinity Shallow/Deep\nP/L-ShD\n>4m\n< 20 mgl-1 CaCO3\nModerate Alkalinity Very Shallow\nMA-vS\n<4m\n20 – 100 mgl-1 CaCO3\nModerate Alkalinity Shallow/Deep\nMA-ShD\n>4m\n20 – 100 mgl-1 CaCO3\nHigh Alkalinity Very Shallow\nHA/M-vS\n<4m\n> 100 mgl-1 CaCO3\nHigh Alkalinity Shallow/Deep\nHA/M-ShD\n>4m\n> 100 mgl-1 CaCO3",
  "extent": "N.I.",
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/nisr/2015/351/schedule/1/part/1/paragraph/7",
    "retrieved_at": "2026-10-29T01:00:03.181368+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}