Knowledge Base
Codes & Standards Reference
Quick reference tables for all UK drainage codes, standards and guidance documents referenced across Quinnsite
Key Codes of Practice and Standards Referenced
| Document | Key Application | Notes |
|---|---|---|
| IH Report 124 Marshall & Bayliss (1994) |
Greenfield runoff rate estimation | Contains the QBAR equation (Eq. 7.1) for calculating mean annual rainfall runoff from small catchments. Used to establish the baseline discharge rate for S3 compliance. Requires WRAP soil classification and FSSR growth curve factors for the relevant hydrometric region. |
| CIRIA C753 The SuDS Manual (2015) |
Comprehensive SuDS design guidance | The industry standard reference for SuDS in the UK. Covers all component types, design procedures, water quality (Chapter 26 Simple Index Approach), treatment train design, construction, adoption, and maintenance. Essential reading for any SuDS designer. |
| Defra/EA SC030219 Rev E | Rainfall runoff management | Practical design guidance for estimating storage volumes, orifice sizing, and attenuation basin design. Uses the Modified Rational Method for smaller catchments. Specifies practical minimum discharge rates (typically 2–5 l/s/ha depending on receiving water). |
| BRE Digest 365 (2016) | Soakaway design | Detailed methodology for soakaway and infiltration trench design. Includes infiltration testing protocols (percolation tests, slug tests), sizing calculations, and factors of safety. Essential for designing infiltration-based SuDS. |
| BS EN 752:2017 | Drain and sewer design | European standard for drain and sewer systems. Sets design return periods and performance criteria for gravity drainage systems. Referenced for SuDS drainage design and discharge to sewers. |
| Environment Agency Climate Change Allowances |
Rainfall uplifting | Peak rainfall intensity uplifts by management catchment and epoch. The 2025 National Standards require the Upper End Allowance (95th percentile) to be applied to design rainfall. Updates issued periodically as climate projections evolve. |
| FSSR 2 & 14 Flood Studies Supplementary Reports |
Rainfall frequency factors | Provide growth curve factors for 10 UK hydrometric regions, used to convert mean annual rainfall to design rainfall for specified return periods. Integral to IH124 QBAR calculations. |
| British Water SIA Guide | Water quality assessment | Practical implementation of the Simple Index Approach (CIRIA C753 Chapter 26) for water quality. Specifies treatment train combinations and efficiency scores for SuDS features. |
| BS 8582:2013 | Surface water management | Code of practice for surface water management for development sites. Covers SuDS design principles, sustainable drainage hierarchy, and construction quality requirements. |
| GRO Green Roof Code 2021 | Green roof design and maintenance | Planning, design, installation, and maintenance guidance specifically for green roofs. Includes substrate depth recommendations for retention and growth, structural loading, and vegetation management. |
| BS 6031:2009 | Code of practice for earthworks | Referenced for design and construction of soil embankments (e.g., detention and retention basin banks). Covers slope stability, compaction, and vegetation establishment. |
Guidance Note: For major developments, it is essential to familiarize yourself with CIRIA C753 and the relevant sections of the 2025 National Standards. Most design errors arise from incomplete or incorrect application of these documents. When in doubt, consult the primary source rather than relying on abbreviated summaries. The calculators in the Catchment are designed to implement these standards correctly; however, they do not replace the designer's professional judgment and detailed site assessment.
Standards Reference Index
Note: This index lists all UK standards, codes of practice, and design methodologies referenced by the Quinnsite calculators. Standards documents must be obtained from their respective publishers.
44 of 44 standards
| Standard Number | Title | Edition/Year | Used By | Standards Area |
|---|---|---|---|---|
| CIRIA C753 | The SuDS Manual | 2015 | All calculators | Comprehensive SuDS design |
| BRE Digest 365 | Soakaway Design | 2016 | BRE Soakaway, BRE365 Test Logger | Infiltration testing & soakaway |
| BS 8515:2009+A1:2013 | Rainwater harvesting systems (withdrawn, superseded by BS EN 16941-1:2024) | Withdrawn | Rainwater Harvesting | Water reuse |
| BS EN 12056-3 | Gravity drainage inside buildings: Roof drainage | 2000 | Building Services ref | Roof drainage |
| BS 7533-13 | Pavements of concrete, clay and natural stone: Permeable | 2009 | Permeable Paving | Paving design |
| GRO Code | Green Roof Code of Best Practice | 2021 | Green Roof | Green roof design |
| BS 8545:2014 | Trees: from nursery to independence | 2014 | Tree Pit | Tree planting |
| EA Climate Change Allowances | Flood risk assessments: climate change allowances | 2022 | Climate Change Comparison, all attenuation | Climate resilience |
| IH Report 124 | Flood estimation for small catchments | 1994 | Greenfield Runoff | Hydrology |
| FEH | Flood Estimation Handbook | Various | Greenfield Runoff (Pro tier) | Hydrology |
| Defra 2025 | Non-statutory technical standards for SuDS | 2025 | Treatment Train, all | National Standards S1–S7 |
| NPPF | National Planning Policy Framework | 2024 | Treatment Train | Planning policy |
| Water UK SSG/DCG | Design & Construction Guide | v2.3 (2023) | Attenuation Storage, Detention Basin | Sewer adoption |
| WIA 1991 | Water Industry Act 1991 – S104/S106 agreements | 1991 | Project Manager | Legal framework |
| Building Regs Part H | Drainage and waste disposal | 2015 | Building Services ref | Building regulations |
| CIRIA C697 | The SuDS Manual (Scotland) | 2007 | All (Scottish projects) | Scottish guidance |
| CIRIA C698 | Site handbook for the construction of SuDS | 2007 | Project Manager | Construction guidance |
| Stokes' Law | Particle settling velocity | N/A | Sediment Forebay | Physics |
| Manning's Equation | Open channel flow | N/A | Swale, Filter Strip | Hydraulics |
| Rational Method | Peak flow estimation (Lloyd-Davies) | N/A | Multiple calculators | Hydrology |
| Darcy's Law | Groundwater flow through porous media | N/A | Soakaway, Filter Drain, Permeable Paving | Infiltration |
| HR Wallingford | Modified Rational Method | Various | Attenuation Storage | Hydrology |
| EA PPG | Pollution Prevention Guidelines | Various | Filter Strip, Water Quality | Pollution control |
| BNG Metric 4.0 | Biodiversity Net Gain metric | 2023 | (Future: S6 module) | Biodiversity |
| Trees & Design | Trees in the Townscape | 2012 | Tree Pit | Urban trees |
| BS EN 858-1/2:2002 | Separator systems for light liquids (e.g. oil and petrol) | 2002 | Oil & Petrol Separator | Pollution control |
| PPG3 (NetRegs) | Use and design of oil separators in surface water drainage | 2006 | Oil & Petrol Separator | Pollution control |
| CIRIA C768 | Guidance on the construction of SuDS & long-term maintenance | 2019 | Maintenance Management Plan | Maintenance |
| BS 3998:2010 | Tree work: Recommendations | 2010 | Tree Pit | Arboriculture |
| BS EN 1433 | Drainage channels for vehicular and pedestrian areas | 2002 | Filter Drain, Swale | Linear drainage |
| DMRB CD 530 | Design of soakaways & infiltration for highway runoff | 2020 | BRE Soakaway (highway context) | Highways |
| Environmental Permitting Regulations | EPR 2016: groundwater & discharge consents | 2016 | Water Quality, Oil Separator | Legal framework |
| HM Treasury Green Book | Central Government guidance on appraisal and evaluation | 2022 | Lifecycle Costing | Economic appraisal |
| FWMA 2010 Sch 3 | Flood and Water Management Act: Schedule 3 SuDS approval | 2010 (commenced 2024) | S1–S7 Compliance Report, all | Legal framework |
Last reviewed: 2026-05-10 · Sources cross-checked against the canonical registry at the time of publication. Standards may be updated; verify currency against the publisher before relying on any citation.