A shape with lion body and the head of a man,
A gaze blank and pitiless as the sun,
Is moving its slow thighs, while all about it
Reel shadows of the indignant desert birds.
– William Butler Yeats
A friend sent me a note last night with the memorable subject line – “slouching towards intermittency” – along with a report from the USGS noting that the agency’s famed Embudo gauge on the Rio Grande, oldest in the system, had slipped below 175 cubic feet per second.
Yesterday’s daily average reported flow for the gauge – 178 cfs – is the lowest for that date in a history (with a data gap of a few years in the early 20th century) going back to 1895.
At these low levels it is too much, despite their excellent work, to expect the sort of precision from the USGS stream gaugers to unequivocally call this “the lowest flow”, but within the margin of error it is statistically indistinguishable from the lowest flows ever recorded at this point in the year on New Mexico’s Rio Grande.
1902, 2002, and 2018.
Nice headline, but…The reason that the Rio Grande won’t become intermittent at Embudo is that there is about 140 cfs spring discharge in the upper Gorge between the NM State Line and the Arroyo Hondo, including a 13 cfs spring, “The Lava Tube”, which may be the largest-volume spring in NM, discharging directly from the river bed. With Colorado presently bearing no delivery obligations to us, these springs are effectively the only reliable water supply for millions of dependents above the Rio Conchos. To be sure, there is the San Juan-Chama Project water, but this is a less-reliable source than the perennial (and almost unnoticed) water of the gorge. BTW: Today’s river runners are floating on at least 30 cfs more than the low ebb of 2002; we’ll see whether it gets lower than the 155 cfs (est.) we boated in the dog days of August, 2002.
I’m happy for you that you’ve got a firm 140cfs up where you live. Absent the supplemental flows being fed in via the Rio Chama from various storage accounts, though, we’re slouching towards intermittency down here.