ID this type of farm BRIDGE, please

[MNRebecca]

What is this bridge for, exactly? Here it is, from both sides:

info:

1. It's old (obviously). Boards (for walking across) seem too rotted to hold much weight.
2. I don't think it's wide enough for a tractor to drive across, but it's obviously not just for human foot traffic, right?
3. The ditch of water beneath it is maybe 10-15 feet wide. I think it's a man-made tributary from the Chippewa River. It seems to run neatly along the boundaries of farm quarter sections in the area. The bridge seems to connect two farms across the water.

Was the water used for irrigation, do you think? What role did the bridge play? Thanks if you can help (or direct me to another source).

[Lelandite]

Looks like a pulley bridge where only one side is opened up (by pulling one side up into the air) to let traffic (boats) through.

There's probably a hundred and one things that the water was used for but since it was made to open, the water was definitely a pathway to bigger waters. Most likely dug wider and deeper by man to help accumudate irragation for the two farms.

Donna in WA who is just guessing.....

[Mysterious Traveler]

It's an interesting structure. Would it be possible to get more pictures, possibly directly down the bridge, from end to end?

[Ann]

Pipeline bridge?

[brooklyn1]

That looks like a canal for transporting small barges... often they would be spanned by variously configured Bascule bridges... used for foot, cart, and livestock traffic. The one you depicted is probably no longer used.

[Bob Noble]

It looks more to me like that is a bridge used to support a big pump for some kind of irrigation. Note the pump in the middle with the overhead to rise the pump.

[John Gilmer]

I suspect that the "bridge" served to hold a "hydralic ram" which uses the velocity of the water to pump a small portion of the water to the level of the surrounding fields.

OR, it could just be a structure to hold a water turbine is the center of the stream.

The structure in the middle tooks like something used to pull something normall in the stream bed to the level of the bridge floor for maintenance.

[Dean Hoffman]

Belt driven powered by an electric motor. Maybe the overhead part is used to pull the pump up to clean the debris that accumulates.

[Larry]

It looks to me like the bridge was built to do exactly what it is doing,which is to hold a turbine pump. It's plenty stout, so maybe it originally held an engine to run the turbine, which has been replaced with an electric motor. The rack in the center is to pull the pump during the winter to avoid freeze or flood damage. The canal is an irrigation canal. Follow it toward the river and you will find a headgate and probably a small diversion dam to channel water into the canal.

[MNRebecca]

Thanks for all the input, everybody. I've sent an inquiry to the local historical society. I'd love to know when this was built. WPA project? Did they have this technology when my family owned the farm (1903ish to 1925ish)? I'll be in the area again for Memorial Day Weekend to decorate the graves of family members and will try to take more pictures then. Didn't get a single one straight across the traveling path of the bridge!

R.

[Jim Elbrecht]

Is there still a Grange or some old agricultural society in the area?

Take some prints to the local gin-mill & diner and ask the old timer sitting at the bar/counter.

Jim

[Ann]

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). Example of one still in use:

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

But the best way to solve the mystery is to inquire locally this weekend.

[MNRebecca]

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?

[Una]

Quite likely. In most of the world where ditch irrigation is used no pump is involved. Methods of getting water from the ditch to the field generally require the ditch water level to be higher than the bottoms of the furrows in the field. To get water across the ditch bank there are siphon tubes, removable barriers as simple as a plank, etc.

Una

[Wallace]

or, if they used a pump initially at ground level, it would be less efficient since it had to do a lot of "sucking". With the bridge in place, they could easily put the pump in the water, driven by a shaft from the motor on the bridge.

I concur that the bridge was probably reused from some other purpose.

[Ann]

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.)

[Grizzly]

Flood irrigation. A system where you divert the stream into a series of irrigation ditches that water the fields passively without the use of pumps. In Phoenix AZ, some people have their lawns done this way instead of using city water. The system was developed by the Anasazi who no longer inhabit the region. The only down side to that are the stinking minnows that wind up in the yards.

[FarmI]

Nope. Hydraulic rams need a head of water above the pump so that the water drops into the ram. - its the action of the water falling into the ram that makes the pumping happen.

[FarmI]

Of course there would have been. Watering can be moved out of the ditch by hand very easily using a simple syphon method and that is common enough even today. See pic on this cite:

[Tony]

Here is a very large one I travel on a couple days a week. All 20 pics are this same bridge. It's a very unique design.

don't know why part of it is concrete? The highest steel span is also wider, it looks as if it were made for large sail boats but I don't think the lake is deep enough for a boat that large. Being so old and carrying a lot of traffic, it under goes an inspection every year and it is closed for the day of the inspection.

It must be a part of the great TVA (Tennessee valley authority) project because they built the dam that made this bridge necessary. In the winter when there isn't a lot of rain they use all the water for hydro-electric and the lake becomes a river again. Some people bought Lake Front houses during the summer, then in the winter it's dirt and mud for hundreds of yards until they can reach the river. Some bitch, some buy 4 wheelers to take advantage of the wintertime fun.