| 1 | 257 | InventoryMethodology_Enum | Tier 1 (point source information) |
| 2 | 258 | InventoryMethodology_Enum | Tier 2 (riverine load) |
| 3 | 259 | InventoryMethodology_Enum | Tier 3 (pathway-oriented) |
| 4 | 260 | InventoryMethodology_Enum | Tier 4 (source-oriented, e.g. SFA) |
| 5 | 261 | InventoryMethodology_Enum | Tiers 1 + 2 |
| 6 | 262 | InventoryMethodology_Enum | Tiers 1 + 2 + 3 |
| 7 | 263 | InventoryMethodology_Enum | Tiers 1 + 2 + 4 |
| 8 | 264 | InventoryMethodology_Enum | Tiers 1-4 |
| 9 | 265 | InventoryMethodology_Enum | Other |
