I'd like to thank everyone who has responded.  Perhaps a little more
information would be of use.  We are primarily looking for examples of
similar dams that have been preserved or that have been listed on the
NRHP.  We had discovered quite a literature on check dams through the
Army Corps and NRCS which were for smaller scale imitation ditch and
erosion control dams.  These are larger structures and the low lying
terraces along the banks would not have formed an effective barrier to
serious flooding.  

Generally, the two dams appeared to be low piles of stone which at one
time extended the width of the river (South Fork of the Flambeau River).
 One of these extends 52 feet across the river and has a 50 ft wide
stone scatter whereas the other is about 61 ft across with a 42 ft
scatter.  Each of these also had a canoe chute, comprised of logs, in
the center of the stream (a portion of the chute is extant in one of the
dams).  The presence of the chute indicates that accommodating fishermen
and recreational canoeists was part of the original design.  Today each
of the dams has a head of about 2 to 3 feet.  They may have had heads as
great as 8 to 10 ft while they were intact.

Photographic evidence indicates that these dams were built in the mid
1930s.  It is widely believed that the two dams were constructed as a
project carried out the by the Civilian Conservation Corps (CCC).  There
was a CCC camp nearby and while they cannot be definitively linked to
the CCC, the time of construction makes the connection likely.  While
the original purpose of the dams is not known, though they were likely
to have served a variety of functions.  There may have been a need for
flow control, but is seems more likely they had a recreational purpose,
possibly to raise the river level for fishing.  In one case, there is
evidence that the locale may have also been used as a ford (there is a
former road to this location now used as fishing access).  The dam may
have enhanced this use.  Since they were built in the 1930s, they post
date the river drive era in northern Wisconsin by about 40 years or so. 
Trucks and trains were hauling the logs in the twentieth century.

Cheers,

Sean


Sean B. Dunham, RPA
Commonwealth Cultural Resources Group, Inc.
Phone:  517-788-3550 / FAX:  517-788-6594
e-mail:  [log in to unmask]
http://www.ccrginc.com