17/09/2015
It is all about FLOW. A more detailed comparison of San Rafael Falls at more similar flows allows for greater appreciation of the significant changes which recently occurred to Ecuador’s largest waterfall. – photo by SARAH LYNN FLECKE
September 15, 2015 – As these photos show, water from above, along with hydraulic undercutting from below, has caused a significant portion of the rock face to shear away and collapse across its entire span, nearly eliminating the second drop of San Rafael Falls.
These pictures also indicate how the capacity of the Quijos watershed to maintain base-flow levels in the Coca River has diminished over the last 10 years. The left image was taken during an exceptionally-prolonged, low-flow period in 2005, when it was estimated that the flow over San Rafael Falls was on the order of 1800 – 2100 cfs (50 – 60 m3/s), based on a group consensus after paddling the Quijos River from Bombón down to the diversion dam site at Salado. It is quite notable that in the right image, which was taken only days after the Quijos watershed had sustained significant flood stage pulses under saturated conditions, appears to have an even lower flow, likely in the range of 1200 – 1500 cfs (35 – 45 m3/s).
The Coca-Codo Sinclair hydroelectric project will require nearly 8000 cfs (222 m3/s) to generate its installed capacity of 1500 MW.
