Results from analysis of sediment located near each outfall (extract)
| Determinand | Outfall 1 | Outfall 2 |
| Water Soluble Boron (mg/kg) | 0.9 | 0.9 |
| Cadmium (mg/kg) | 1.3 | 2.1 |
| Copper (mg/kg) | 374 | 127 |
| Iron (mg/kg) | 4.0 | 3.9 |
| Lead (mg/kg) | 930 | 330 |
| Mercury (mg/kg) | 0.46 | 0.60 |
| Zinc (mg/kg) | 1170 | 293 |
| Chloride (mg/kg) | 137 | 24 |
| pH | 7.0 | 7.2 |
taken from: Technical Reason for the Task. Welsh Harp Reservoir Reed Bed Feasibility Study, Halcrow, May 2001