RC04 - Below Huayllampi

Site Code: RC04. GPS: S12°81455, W75°905201. Elevation: 1059m asl.

Water Quality Data

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

RC04 July 2019 November 2019
Season: Austral Winter Austral Summer
Date: 10.07.2019 18.11.2019
Time: 11.00am 12.45pm
Width (m) 40 22
Depth (Av.) (m) 0.402 0.182
CSA (Av.) (m²) 16.08 4.004
Velocity (Av.) (m/s) 0.474 0.707
Discharge (Av.) (m³/s) 7.621 2.835
Riverbed sediment Cobbles & boulders Cobbles & boulders
Temp. (Atmospheric) (°C) 29 33
Temp. (Water) (°C) 18.31 23.46
Atmospheric pressure (mbar) 894 879
Dissolved oxygen (mg/l) 7.14 6.51
Dissolved oxygen (%) 85.47 89.63
pH 5.82 8.94
Conductivity (µS/cm) 416 452
Total Dissolved Solids (ppm) 208 226
ORP (mV) 347.17 126.73
Turbidity Clear Clear
Alkalinity (mg/l CaCO3) Pink to colourless 114 (1.6N) Pink to colourless 133 (1.6N)

Data Analysis

Discharge at this site is impacted by the catchment hydroelectric water management system. This site is bypassed by the tunnel system that connects the Capillucas and lower El Platanal reservoirs.

At just over 1000m asl the DO readings at RC04 are as expected for both the July and November 2019 data sets. The raised elevation and great fluctuations in daily temperatures in such narrow and sheltered valleys will produce fluctuations in maximum absolute oxygen capacity and, consequently, the percentage saturation that therefore fluctuates with that rhythm. At DO levels from 6.14-7.28 mg/l and 85-93% oxygen saturation aquatic vertebrates survive and invertebrates thrive.

The conductivity reading at this site is 395-452 µS/cm. The level of conductivity in the Rio Ca~nete at RC04 might be an indicator of limited contamination from waste waters and agricultural runoff.

A pH of 8.94 is what would be expected and suitable for aquatic life. It does not approach the tolerances of most aquatic vertebrates and invertebrates. The July data requires confirmation.

Site Description

Site RC04 is located below the town of Catahuasi in the arid upper tropics. The Rio Canete, at this point, is downriver of limited intensively farmed lands. The use of pesticides and fertilizers is probably only higher in the various sub-catchments in the temperate zone. The valley has a narrow steeply v-shaped profile with a tall river cliff on the north bank, indicating earlier periods of significant flooding perhaps at the end of the last Ice age. As elsewhere in the drainage basin discharge is highly seasonal. Discharge measurements in February-March are considerably greater. The channel itself is choked with large boulders and rocks from land slides and earlier flooding events.

The banks are lined with scattered willow. The cultivation of crops is exclusively for subsistence farming in the marginal social groups forced onto the poorer soils. The production of maize, bananas dominate with smaller areas of avocado production. As with elsewhere in the catchment there is little or no natural vegetation remaining. The fauna and flora in the valley are depauperate with relictual west flanks endemics. The impact of water quality on the health of the environment and populations of wildlife occupying these lands is the subject of some aspects of our study here. There is a trout hatchery at this site which is fed by a nearby spring.

RC04 View upstream Site RC04 - Study site location: accessed through the fish farm. (John Forrest)

Site RC04 - the study site. (John Forrest) Site RC04 - the study site. (John Forrest)

RC04 View upstream Site RC04 - View upstream. (John Forrest)

RC04 View downstream Site RC04 - View downstream. (John Forrest)