| 1. DRAINMAX Tunnel |
7. Sedimentation/filter chamber |
| 2. Tunnel side and top backfill |
8. Flushing chamber |
| 3. Geotextile |
9. Rainwater inlet |
| 4. Tunnel overburden |
10. Maximum water level |
| 5. Topsoil |
11. Geotextile composite bottom layer |
| 6. Rainwater distribution |
|