RC02B - Puente Socsi

Site Code: RC02B. GPS: S13°028536, W76°194156. Elevation: 310m asl.

Water Quality Data

The following river and water quality data was collected from this site:

RC02B November 2021 July 2022 October 2022
Season: Austral Summer Austral Winter Austral Winter
Date: 7.11.21 15.7.22. 19.10.22
Time: 10.30 18.00 18.30
Width (m) 45.0 46.0 46.2
Depth (Av.) (m) 0.53 - 0.41
CSA (Av.) (m²) 23.85 - 18.94
Velocity (Av.) (m/s) 1.22 - 0.66
Discharge (Av.) (m³/s) 29.097 <15.0 12.502
Riverbed sediment Mainly cobbles Pebbles & Cobbles Mainly cobbles
Temp. (Atmospheric) (°C) 20.0 15.0 18.0
Temp. (Water) (°C) 22.43 18.40 21.59
Atmospheric pressure (mbar)   978 979
Dissolved oxygen (mg/l) 8.70 13.16 6.34
Dissolved oxygen (%) 102.02 146.30 74.53
pH 8.39 8.45 8.16
Conductivity (µS/cm) 541 426 441
Total Dissolved Solids (ppm) 271 213 221
ORP (mV) 45.7 119.2 169.7
Turbidity Clear: Clear: slightly murky Clear: slightly greyish
Alkalinity (mg/l CaCO₃) 139 (1.6N) 125 (1.6N) 112 (1.6N)
Alkalinity Tester (ppm CaCO₃) (120) 102 100

Data analysis

The discharge at RC02B now contains the water that was diverted from the river at the Capillucas dam. It is still subject to hydro-electric plant control but appears to be maintained at a fairly constant 12-15 cumecs (the November 2021 figure is probably an over-estimation of velocity: approximately half that stated). The discharge at this point in the river is at its maximum because a short distance downstream a significant amount is abstracted at Bocatoma Socsi to supply the urban areas and irrigation projects on the coast strip.

There is some variation in the DO levels, with higher figures recorded in July.

Conductivity levels are as expected in the lower valley given that the river is now passing through several small towns and more expansive irrgiated areas draining into the river.

The average pH is over 8.0 which is ideal for aquatic life.

Site description

RC02B is situated immediately upstream of Puente Socsi - the Socsi bridge. The right hand bank has been stabilised with large boulders creating an artificial bank. The left bank has been remodelled to accommodate the frequent arrival of whitewater rafting boats to deposit their passengers. Consequently, there is rubbish lining the bank.

Approximately 100 metres upstream the banks on both sides have reverted to their natural state lined with with extensive river cane, scattered acacia and stands of stunted willow.

Beyond the vegetation lining the banks, both the small flood plain and wider river terraces are intensively farmed, principally with grapes and a range of fruit trees.