Environmental Assessment decomposition for New Tyne Crossing
System
New Tyne Crossing Transport Appraisal System, session 4 of decomposition. This session decomposed the Environmental Assessment Subsystem into five components covering all DMRB LA 104 environmental topics.
Decomposition
The Environmental Assessment Subsystem was decomposed into five components separating assessment by regulatory domain:
- Environmental Impact Assessment Module — assesses all 14 DMRB LA 104 environmental topics
- Air Quality and Noise Modelling Engine — computes annual mean NO2/PM2.5 concentrations at receptors within 200m and LA10,18h/Lnight noise levels within 600m
- Greenhouse Gas Assessment Module — quantifies lifecycle carbon emissions (construction, maintenance, 60-year operation) in tonnes CO2e per TAG A3
- Biodiversity and Water Environment Assessor — calculates Biodiversity Net Gain using Defra Metric 4.0, targeting minimum 10%
- Distributional Impact Assessor — evaluates distributional impacts across 8 TAG A4.2 categories by income quintile and area type
Architecture decision ARC-DECISIONS-005 documents the five-component split driven by EIA framework (LA 104), air quality and noise (DMRB LA 105/111), GHG (TAG A3), ecology/water, and distributional impacts as distinct regulatory domains requiring independent assessment methods.
Artefacts
| Type | Count |
|---|---|
| Architecture decisions | 1 |
| Subsystem requirements | 6 |
| Interface requirements | 3 |
| Verification entries | 3 |
Interfaces
Three cross-subsystem interfaces defined:
- Air Quality/Noise Engine → EIA Module: receptor-level results transfer
- GHG Assessment Module → EIA Module: annual CO2e emissions by source category
- Transport Demand Modelling → Environmental Assessment: link-level AADT flows, speeds, and HGV percentages
Reconstructed from AIRGen data — original journal post lost to session failure.