RT09A2 - Below Manantial
Site Code: RT09A2. GPS: S12.267975, W75.771023. Elevation: 3384m asl.
Water Quality Data
| RT09A2 | July 2022 |
|---|---|
| Season: | Austral Winter |
| Date: | 29.6.22 |
| Time: | 11.00 |
| Width (m) | 6.0 |
| Depth (Av.) (m) | 0.88 |
| CSA (Av.) (m²) | 5.28 |
| Velocity (Av.) (m/s) | 1.08 |
| Discharge (Av.) (m³/s) | 5.702 |
| Riverbed sediment | Cobbles & Boulders |
| Temp. (Atmospheric) (°C) | 25 |
| Temp. (Water) (°C) | 10.63 |
| Atmospheric pressure (mbar) | <600 |
| Dissolved oxygen (mg/l) | 6.31 |
| Dissolved oxygen (%) | 97.00 |
| pH | 7.64 |
| Conductivity (µS/cm) | 649 |
| Total Dissolved Solids (ppm) | 325 |
| ORP (mV) | 188.7 |
| Turbidity | Clear: blue/grey |
| Alkalinity (mg/l CaCO₃) | 190 (1.6N) |
| Alkalinity Field Tester (ppm CaCO₃) | 192 |
Data Analysis
The discharge at this site on the Rio Alis was significant (5.7 cumecs) as a result of the combined river discharge and manantial outflow.
At nearly 3400m asl the average DO reading at RT09A2 (6.31mg/l) was within the range to be expected.
The conductivity reading at this site (649 µS/cm) is higher than expected for a site located at this elevation in the drainage basin, above most settlements. Furthermore, it would appear to reflect the impact of the river water from upstream given that the water entering the river from the manantial a short distance upstream, has a much lower conductivity level.
The pH reading of 7.64 is as expected. At these levels the alkalinity of the river is suitable for aquatic life.
Site Description
Site RT09A2 lies in the Alis valley immediately downstream of the manantial at 3384m asl and just above a road bridge across the river. The valley at this point is narrow and very steep sided as is the main channel.
The left river bank at the site is overgrown with dense coniferous woodland.
Sites RT09A.M & RT09A2 - location of the study sites T9A2 & T9A.M.
Site RT09A2 - the study site (June 2022). (John Forrest)
Site RT09A2 - view downstream from the study site (June 2022). (John Forrest)
Site RT09A2 - view upstream from the study site (June 2022). (John Forrest)