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)

Flood features on Burro Creek and Big Sandy River, AZ

Some ephemeral features and some persistent features. For the full
gallery in its geotagged glory check out:

http://picasaweb.google.com/drjerque/BigSandyRiverAndBurroCreek#

Bottom line: Big Sandy had a decent, but not extraordinary flood above
the confluence with Burro Creek. Burro Creek had a notable flood that
buried vegetation along the edge of the channel with sediment and
nearly lapped onto a late Plesitocene terrace. Burro Creek is a
notorious flood machine that drains a very rugged part of west-central
Arizona.

I blew it by not visiting the Big Sandy/Burro Creek confluence.

(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.