Groundwater discharges from aquifers into a number of surface water bodies throughout the region and there is the potential that groundwater high in dissolved reactive phosphorus could contribute to the decline of surface water quality. Phosphorus may be derived from soil, rocks and minerals in the aquifer as water passes through them, as well as from anthropogenic sources including agricultural and industrial activities. See the LAWA phosphorus factsheet for more information.
Map usage: Drag and scroll on the map to move and zoom in on areas of interest, click on a site circle to see more information and subset the table below to that specific site, and use the selection box on the map ( ) to subset table data to sites in that area.
Table usage: All calculations use dissolved reactive phosphorus (mg/L). Click on the +/- button at the end of a row to see the raw sample data and highlight that site on the map above. Click on table headers to sort the data by that column – holding the shift key allows sorting over multiple columns.
| Connectivity | Attribute band | No. Sites |
|---|---|---|
| A (direct) | A (≤0.006 mg/L) | 1 |
| A (direct) | B (>0.006 and ≤0.010mg/L) | 3 |
| A (direct) | C (>0.010 and ≤0.018 mg/L) | 6 |
| A (direct) | D (>0.018 mg/L) | 4 |
| B/C + unknown | A (≤0.006 mg/L) | 3 |
| B/C + unknown | B (>0.006 and ≤0.010mg/L) | 5 |
| B/C + unknown | C (>0.010 and ≤0.018 mg/L) | 15 |
| B/C + unknown | D (>0.018 mg/L) | 35 |
| Total sites | A (≤0.006 mg/L) | 4 |
| Total sites | B (>0.006 and ≤0.010mg/L) | 8 |
| Total sites | C (>0.010 and ≤0.018 mg/L) | 21 |
| Total sites | D (>0.018 mg/L) | 39 |
The National Policy Statement on Freshwater Management (NPS-FM) classes river water dissolved reactive phosphorus concentrations into four attribute bands based on river ecosystem health. Annual median groundwater dissolved reactive phosphorus concentrations are evaluated below against these bands.
Shallow groundwater within Connectivity Category A (direct) poses a greater risk from groundwater dissolved reactive phosphorus to ecosystem health in the surface water system than groundwater within other Connectivity categories. See groundwater connectivity for more information on surface water connectivity categories.