{
  "url": "https://openlegislation.uk/surface-waters-river-ecosystem-classification-regulations-1994/schedule",
  "json_url": "https://openlegislation.uk/surface-waters-river-ecosystem-classification-regulations-1994/schedule.json",
  "legislation": "uksi/1994/1057",
  "legislation_title": "The Surface Waters (River Ecosystem) (Classification) Regulations 1994",
  "legislation_url": "https://openlegislation.uk/surface-waters-river-ecosystem-classification-regulations-1994",
  "path": "schedule",
  "kind": "schedule",
  "number": null,
  "heading": "RIVER ECOSYSTEM CLASSIFICATIONS",
  "text": "(1) Class\n(2) Dissolved Oxygen % saturation 10 percentile\n(3) BOD(ATU) mg/l 90 percentile\n(4) Total Ammonia mg N/l 90 percentile\n(5) Un-ionised Ammonia mg N/l 95 percentile\n(6) pH lower limit as 5 percentile; upper limit as 95 percentile\n(7) Hardness mg/l CaCO3\n(8) Dissolved Copper μg/l 95 percentile\n(9) Total Zinc μg/l 95 percentile\nRE1\n80\n2.5\n0.25\n0.021\n6.0-9.0\n≤ 10\n> 10 and ≤ 50\n> 50 and ≤ 100\n> 100\n5\n22\n40\n112\n30\n200\n300\n500\nRE2\n70\n4.0\n0.6\n0.021\n6.0-9.0\n≤ 10\n> 10 and ≤ 50\n> 50 and ≤ 100\n> 100\n5\n22\n40\n112\n30\n200\n300\n500\nRE3\n60\n6.0\n1.3\n0.021\n6.0-9.0 ≤ 10\n> 10 and ≤ 50\n> 50 and ≤ 100\n> 100\n5\n22\n40\n112\n300\n700\n1000\n2000\nRE4\n50\n8.0\n2.5\n—\n6.0-9.0\n≤ 10\n> 10 and ≤ 50\n> 50 and ≤ 100\n> 100\n5\n22\n40\n112\n300\n700\n1000\n2000\nRE5\n20\n15.0\n9.0\n—\n—\n—\n—\n—",
  "extent": null,
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/uksi/1994/1057/schedule",
    "retrieved_at": "2026-10-29T13:34:37.410516+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."
}