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Hydroclimatology and Solar Explorations

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Is the Lake Mead Controversy Settled?

Perhaps the more reproducible parts of this USA Today piece by Felicia Fonseca prove I was right relating to a public controversy about the state of climate as signified by Lake Mead water levels.  The piece had to acknowledge moist weather conditions for the previous winter, across watersheds that feed moisture to the Colorado River.  That was in line with my overall forecasting.   That controversy happened because a journalist reached out to me for an independent opinion in 2016.  Now that a few years have passed, and since my recent posts have been working their way downstream from the upper catchments of the Colorado River, this may be a good time to revisit.  Here’s a closer look for me at least, at the Lake Mead monthly surface elevation chart.

By now any reader will be well versed in viewing these featured plots.  In this case, I’m simply plotting monthly averaged Lake Mead water levels (in feet above mean sea level (famsl) for the record span provided by the US Bureau of Reclamation  (BOR) [1].  The visual effects are clearly human-managed but beautiful just the same, to me at least (only a blog).

In the prior journalism feature in June of 2016, an exploration was developed between the views of the BOR, the opinions of another expert Brad Udall, and myself about the meaning of the historically low elevation of Lake Mead at that time.  Indeed my featured image corroborates this historic low.

My view then was that we’d have to have historic highs for Mr. Udall to back away from a drought opinion.  That’s only my opinion as always and no attempt is made to otherwise disrespect.  In fact I’m sometimes a fan of his work.

I do think my view then was appropriate.  As the following image supports, the recent low of 2016 was accompanied by generally higher average discharges from the lake downstream through the USGS Hoover Dam stream gage [2].  Perhaps if the discharges through the Hoover drain had followed the lower-magnitude patterns of the 70s for example, then some crude comparison for a climate change exploration might be possible.  Otherwise one can only conclude I think that  in the 70’s flows into Lake Mead equaled or exceeded flows out, and the water level (red line) in the lake rose.  Then in the first decade of the 21st century, flows out of Lake Mead exceeded flows in, and the water level in the lake dropped.

To me the underlying question of why flows into Lake Mead rise and fall is more pertinent.  That is of course in part a result of the management of Lake Powell as reflected by the record at Lee’s Ferry, its pour point.   But no matter how the data is profiled, certain completely natural spikes in flow, such as in the mid 1980s and the late 1990s, are apparent in the chart above and also in the stochastic strip below.  Note especially the mid 1980s surge which can be seen as a red and green band in the central Lee’s Ferry strip and even in the outflow record for Hoover Dam (the beige and yellow band in the mostly orange strip), which is Lake Mead’s pour point.

This helps to reflect finally and once again on the ongoing Hoover Dam controversy between Brad Udall, his many colleagues, and myself.  I follow the stochastic hydrology which overlaps with the Animas strip plot at that top row of the image above.  Brad and his colleagues appear to follow one notion from the mostly man-managed Lake Mead at the bottom row.  I invite them all to join me and a handful of early adopters back up to the top row and then to develop a new respect for the bottom row.  There they can explore and perhaps help advance or at least corroborate the Solar Forcing Hydro Circulation alternate conceptual model [3].  For example, even when I simply overlay the solar cycle of concern [4] on an annual resolution over the inflows to and outflows from Lake Mead, I think there is something to talk about!

In any case, it might have value at times but maybe not always ideal to use a mostly human-managed water feature as a climate guide.  The orange strip shows how much is necessarily filtered out.  There are many worthy USGS gages which lie upstream beyond the influence of the Hoover drain.  Simply refer to the higher upstream stream gages for some ideas.  Clearly a large reservoir on Lake Mead’s scale leaves a significant impression whether viewed by monthly lake levels shown earlier in this post and by discharge rates past the Hoover Dam pour point.

This is only a Blog

Because it is a great integrator of hydrological effects across a multistate region, Lake Mead’s otherwise human-managed water levels can possibly be related to solar cycles, one cycle at a time. Consider the next stacked stochastic strips especially in light of the previous time series plots I prepared.  The top one in this stochastic strip set is the solar sunspot number record and the bottom is a repeat of my second image, namely the water level at Lake Mead.

If my paper [3] is right then simply because of the increases and decreases in circulated moisture triggered by sunspots, humans have often managed the reservoir level of Lake Mead in the 1150 to 1200 ft amsl general “blue” level.  As sunspot numbers decay, moisture recharging diminishes, but the lake continues to be drained in accordance with interstate compact obligations.  If sunspot peaks are high and closely packed, the moisture recharge to the watershed is augmented and ultimately the “blue” level upgrades to “green” for a level above 1200 ft amsl. If sunspot peaks are low and/or widely spaced, then as the moisture accordingly diminishes, and the lake is further drained, the water levels can lower further. None of this is necessarily controversial, so long as it gets no play in that Lake Mead debate.

As always this topic generates discussion with my colleagues at LACF.  Maybe I might be able to relate the PDO to the blues and the El Nino’s y Nina’s to the greens of these Evaporation minus Precipitation maps.  That’s just a general thought but their recollections shared corroboration across these time series.  The SSN correlations in any case can be calculated and ranked.

Draft

featured image from a US Bureau of Reclamation page

Note about the Hoover Dam stochastic strip plot (orange plot),  I can’t access direct discharge information for dates after June of 2017 from USGS any longer.  Apparently that responsibility has been taken off of their hands and turned over to the US BOR.  Accordingly for the most recent period I’ve had to work out a regression equation, based on a few months of daily data between the gage elevation values and my own draft estimates of the acre feet discharged past this drain.

References

[1] http://lakemead.water-data.com/index2.php

[2] https://waterdata.usgs.gov/nwis

[3] Wallace, M.G., 2019, Application of lagged correlations between solar cycles and hydrosphere components towards sub-decadal forecasts of streamflows in the Western US.   Hydrological Sciences Journal, Oxford UK  Volume 64 Issue 2.   doi: 10.1080/02626667.2019.

[4] http://www.sidc.be/silso/datafiles

 

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