The 1993 mega-debris pile on the lower Verde River, AZ

I just had 2.8 Gb of old slides scanned and found my favorite flood
debris picture in the world. This is me standing in the midst of the
enormous flotsam pile that was deposited along the lower Verde River,
1993 following two very large floods that occurred back-to-back that year.

Once I saw this mess, I was hooked and made studying the historical
and paleoflood history of the Verde River one-half of my PhD
dissertation at U or A. Stay tuned for more pictures of this event and
how it compares to the recent flooding.

Another Verde River photo comparison: 2009-2010

OK, bear with me. this one is pretty cool. My colleague over at AZGS,
Ann Youberg, sent me a photo of the paleoflood study site that she
took on a float trip in April 2009. Here it is compared to the one
that I took last week. Amazing change. Particularly interesting in
that many of mine follow the occurrence of floods, and hers happens to
not follow one. The differences are pretty obvious. Notable is the
removal of an inset deposit (hosting much of the vegetation) that is
likely linked to the 2005 flood. Thus emphasizing the transient nature
of fluvial historical and paleoflood records...particularly the
deposits from low and moderate magnitude flows.

Ann, you really nailed the positioning of the image. Thanks! Next time
you float the Verde, give me a call. I may just drop everything and
tag along.

(download)

18 years of flood-wrought change, Verde River, AZ

This series of photos documents changes that have occurred in a
tributary-mouth slackwater deposit site along the lower Verde River,
Arizona. It begins in 1992 and includes images from 1996, 1997,
1998(2), 1999, 2000, 2005, and 2010. The series includes several large
floods down the Verde as well as a couple of floods down the
tributary. Sadly, I don't have a roughly matching photo directly
following the record flood of 145,000 cfs that buried this site in
sediment in 1993.

The terrace is one of 4 at this site that support a paleoflood record
in excess of 1500 years for the Verde River. The transformations that
this terrace has undergone in the last 18 years, however, supports the
assertion that most (all?) Holocene fluvial paleoflood records are
inevitably incomplete. Note how inset terraces come and go.

We busted our butts getting down to this site last Tuesday...not a
trivial drive after a large flood...and grabbed some data, some
photos, and some new incentive to finally finish our manuscript about
the flood history of the river.

We do have a publication about this site already:

House, P.K., Pearthree, P.A., and Klawon, J.E., Historical flood and
paleoflood chronology of the lower Verde River, Arizona: Stratigraphic
evidence and related uncertainties, in Ancient Floods, Modern Hazards:
Principles and Applications of Paleoflood Hydrology. AGU Water Science
and Application Volume 5.

https://www.agu.org/pubs/booksales/books/HYWS0053541.html

(download)

Verde River, AZ flood update

We have been studying the stratigraphic record of floods on the lower
Verde River, AZ for 17 years. After each notable flood we have
revisited this particular site near Sheep Bridge.

This site has a firm hydraulic control and produces a reliable rating
curve. When floods overtop the surface in the background (behind Phil)
the discharge is greater than 100,000 cfs. Thus, when the gage
reported 115,000 cfs on Jan 21-22, it seemed improbable but the number
meant drop everything and head to the field site. Well worth it.

The river clearly experienced a large, but likely brief, peak over
100,000 and we collected data relevant to finish a paper some 17 years
in the making. The paper compares the historical record to a
paleoflood record more than 2500 years long (based on multiple sites).

Notes:

1. In Jan 1993, this site experienced a discharge of 145,000 cfs.
2. The 'inset' photo' shows the same site in 1998.
3. Conditions remain good for additional flooding.
4. I will be posting addiitional details when I get back from the field.

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