On Wed, 26 May 2010 12:02:52 -0700, MNRebecca wrote:

On May 26, 12:31Â*pm, Ann wrote:

Courtesy of Google, it looks like what's referred to as a pony truss
bridge. In the early 1900s, they were the cheapest bridge design for
short spans and a number of companies made them. By the time the
depression and WWII were over, highway departments had moved on to
newer designs (than steel truss). Â*Example of one still in use:

http://bridgehunter.com/in/gibson/2600283/

Consider the possibility that "your" bridge was repurposed from its
original use/location. Â*As those bridges were phased out, some were
probably free for the taking.

I am LOVING the idea that the reason my tough ol' great great grandma
had $5,000 to give each grandchild in the 1920s (money that disappeared
in 1929, of course) was because she looked out over the tributary ditch
one day and said, "You know, if I took one of those bridges they're
giving away and put it across the ditch, I could rig up a pumping system
to better irrigate my fields!" But would there have been ditches
WITHOUT such bridges in the first place? How did you get the water out
of the ditch and onto the field without the bridge/pump system?

You mentioned in your op that the ditch is along/on the property line.
It would seem that to irrigate farm A, it would have been simpler to put
the pump on the bank and run an intake pipe up from the ditch. But say
both farm A and farm B wanted to irrigate. The bridge and a single pump
might have been the more frugal solution.

(Yes, I know that's a stretch.)