DIY Bridge

[dodge man]

I agree with one thing, you need to do something. A bridge or culverts with a concrete top that allows water over the top during high flows would both be good solutions.

 

[AnotherBueller]

If you are going to dig the creek bed for a bridge that's probably fine but for culverts, I would advise against it will only fill back up with sediments and your culvert will end up half full of dirt within a few years...

We built a low water bridge at the local non-profit camp and the leader decided (against a lot of advice, but he knew better) to put in ten 12" diameter X 8' long concrete pipes to save money. Creak is ~18' wide with very little to no slope, and dry most of the year. 5 years later its a low water dam.
You need the right amount of slope and big enough diameter so that the flow can/will flush the sticks and debris out.

 

[Rockbadchild]

We built a low water bridge at the local non-profit camp and the leader decided (against a lot of advice, but he knew better) to put in ten 12" diameter X 8' long concrete pipes to save money. Creak is ~18' wide with very little to no slope, and dry most of the year. 5 years later its a low water dam.
You need the right amount of slope and big enough diameter so that the flow can/will flush the sticks and debris out.

My point is if you excavate the creek bed downstream and/or upstream it will simply get filled back up especially in a sandy shallow waterways ... you can't make a creek steeper by simply dig it in, well you can but it won't stay like that... lets say the creek flow at 1% slope, you dig in a slope at 3% for 50 feet. You will have a foot tall ledge at the end (excavated creek bed to original creek bed elevation differences) that ledge will trap sediments and gets filled back up until the creek bed is back at its original grade and you dig that for no reason.

 

[airbiscuit]

Man vs. Nature

 

[tree grower]

In a 50-yr career building stream crossings for 100K lb log trucks I learned that bridges are always better than culverts. They take more careful planning and are more expensive to build initially, but they will always pass more water--and with less impact--than culverts. If the terrain in your case will allow it, build relief dips on both sides of the bridge. When the flood waters get high enough to lap at the bottom of the bridge you want them to continue downstream by going around the bridge, not over it. When the water subsides it will be much easier and cheaper to repair the eroded roadway on both sides of the bridge than repairing the bridge itself.

 

[Rockbadchild]

I find the situation pretty challenging, the problem I see here for a bridge, or a culvert for that matter is the creek has no banks, so lots of material is going to be required to raise the road, in order to create the bridge abutments to create enough elevation to allow room for the water to go under at high water level...even for a culvert lots of material is going to be needed... I hope he can get his hand on some cheap material.

 

[beeforty]

Now that we're finally getting too much rain here in California all at once I'm glad I have a bridge with lots of clearance (8' high and 48'wide). My creek went from being ankle deep and 8' wide to up 5' deep and 35' wide on several occasions in the last month. As far as the idea of letting water over flow a hard surface or coming out of a culvert, I've seen what I call the "waterfall effect" where the running water scours out the downstream side of the discharge point eroding the creek bed when experiencing high flows. Often it may fill back up with silt when the fast flowing water subsides but often leaves of hole, or a pool, check out county culverts in your area. Also I've seen where the displaced material can create a sandbar barrier that further down that also alters the flow to one side or the other downstream. Whatever you decide, I like that quote from a movie of Morgan Freeman, " Go big or go home"!

 

[WranglerX]

Now that we're finally getting too much rain here in California all at once I'm glad I have a bridge with lots of clearance (8' high and 48'wide). My creek went from being ankle deep and 8' wide to up 5' deep and 35' wide on several occasions in the last month. As far as the idea of letting water over flow a hard surface or coming out of a culvert, I've seen what I call the "waterfall effect" where the running water scours out the downstream side of the discharge point eroding the creek bed when experiencing high flows. Often it may fill back up with silt when the fast flowing water subsides but often leaves of hole, or a pool, check out county culverts in your area. Also I've seen where the displaced material can create a sandbar barrier that further down that also alters the flow to one side or the other downstream. Whatever you decide, I like that quote from a movie of Morgan Freeman, " Go big or go home"!

Dittos in Sierra foothills and all up and down the San Joaquin Valley ....

 

[garymartin63965]

In a 50-yr career building stream crossings for 100K lb log trucks I learned that bridges are always better than culverts. They take more careful planning and are more expensive to build initially, but they will always pass more water--and with less impact--than culverts. If the terrain in your case will allow it, build relief dips on both sides of the bridge. When the flood waters get high enough to lap at the bottom of the bridge you want them to continue downstream by going around the bridge, not over it. When the water subsides it will be much easier and cheaper to repair the eroded roadway on both sides of the bridge than repairing the bridge itself.

“If the terrain allows it, build relief dips on both sides of the bridge.” This sounds like a good idea. Certainly something to look into. Thanks.

 

[garymartin63965]

So, I talked with a guy today, who does excavation, and he’s been building bridges (over creeks) with ‘retired’ flatbed trailers. The flatbeds are usually 48’ to 53’ long. In many cases he welds two trailer abreast so the crossing is 16’ wide. They also install buttress blocks, rip rap rock & gravel. He’s supposed to call me tonight to let me know when he can come & look at my situation. (Hasn’t called yet)
We’ll see what he has to say soon I hope.

 

[airbiscuit]

Now you're talkin!

 

[ning]

So, I talked with a guy today, who does excavation, and he’s been building bridges (over creeks) with ‘retired’ flatbed trailers. The flatbeds are usually 48’ to 53’ long. In many cases he welds two trailer abreast so the crossing is 16’ wide. They also install buttress blocks, rip rap rock & gravel. He’s supposed to call me tonight to let me know when he can come & look at my situation. (Hasn’t called yet)
We’ll see what he has to say soon I hope.

I'm sure it'll cost more than your original ideas - but you'll never be sorry for doing it right.

 

[no eyed deer]

It is hard to estimate without knowing all the data necessary to do the calculation... in order to calculate you need to know the 100 years storm precipitation for your area, the stream basin area, the upstream volume and the flow of that volume... without these it is impossible to calculate... so if you don't know and won't find out then overkill it, perhaps have three pipe and have the road build as demonstrated below so if it's overflow it will flow on each side of the culvert on the road.

other than that, my opinion is most of the concrete work seems over kill.. thrench out 12 inch below the culvert grade and back fill with A gravel, compact, back fill the rest with A gravel and compact every foot... if you want a up stream and down stream concrete bulkhead fine but the rest is over kill.

View attachment 777976

I was hoping to find someone talk about this before I weighed in. This is all very true the calculations needed is called water delineation , it's where you find the amount of rain water that could flow in your area the short version of this it takes in a count for all the rain that washes in from the hills and mountains some places require you to a count for the big " 100 year storm" others need the: 200 year storm " that's why you see big culverts with a trickle running thru them .

If permits aren't a concern and certifications for watercourse alterations and you are doing this yourself. I'd look at changing the direction of your lane to cross the water perpendicular at the the shortest points ( clearing trees might be cheaper than running a longer span over your gap. )

I would suggest also avoid altering the path of the water . Water tends to cut its own path naterally even after we reroute it.

Us engineers the military would inplace what we call a non standard bridge.
You could use round timber or square timber of course pressure treated lasts longer .

You can determine what size lumber is required when you know the largest load it will need to traffic and the span


Lastly with inflating multiple culverts consider if there could be significant debris in the water that could block your water flow causing a wash out

 

[garymartin63965]

No Eyed Deer you certainly gave me some more to think about. Changing my driveway’s path, so it crosses perpendicular to creek/ water isn’t an option right now. My property is on the east side of the creek, the county road is on the west side of the creek & all I have is a 30’ easement. Neither neighbor wants to sell me an acre or two to change the driveway.
It’s been a real PITA to get anyone to give me an estimate on building a bridge. I do have a guy ready to clean up the creek bed and remove the piled up gravel on the side of the drive as soon as the water stops running. It’s down to a trickle now but we’re supposed to get somewhere between 2-8” of snow in the next 24 hours. Hopefully he’ll still be available after it melts and runs off.
I’ll probably make do with that until I can find some good (& affordable) bridge materials. I have about 25 acres of timber here. It’s not good timber but I could probably find enough trees to set them side by side until they’re wide enough to drive over.
Thanks for the thoughts & comments.

 

[no eyed deer]

No sweat my friend , hope it all works out for you

 

[airbiscuit]

No Eyed Deer you certainly gave me some more to think about. Changing my driveway’s path, so it crosses perpendicular to creek/ water isn’t an option right now. My property is on the east side of the creek, the county road is on the west side of the creek & all I have is a 30’ easement. Neither neighbor wants to sell me an acre or two to change the driveway.
It’s been a real PITA to get anyone to give me an estimate on building a bridge. I do have a guy ready to clean up the creek bed and remove the piled up gravel on the side of the drive as soon as the water stops running. It’s down to a trickle now but we’re supposed to get somewhere between 2-8” of snow in the next 24 hours. Hopefully he’ll still be available after it melts and runs off.
I’ll probably make do with that until I can find some good (& affordable) bridge materials. I have about 25 acres of timber here. It’s not good timber but I could probably find enough trees to set them side by side until they’re wide enough to drive over.
Thanks for the thoughts & comments.

Is the picture you posted oriented with North on the Top?

 

[AnotherBueller]

Now that we're finally getting too much rain here in California all at once I'm glad I have a bridge with lots of clearance (8' high and 48'wide). My creek went from being ankle deep and 8' wide to up 5' deep and 35' wide on several occasions in the last month. As far as the idea of letting water over flow a hard surface or coming out of a culvert, I've seen what I call the "waterfall effect" where the running water scours out the downstream side of the discharge point eroding the creek bed when experiencing high flows. Often it may fill back up with silt when the fast flowing water subsides but often leaves of hole, or a pool, check out county culverts in your area. Also I've seen where the displaced material can create a sandbar barrier that further down that also alters the flow to one side or the other downstream. Whatever you decide, I like that quote from a movie of Morgan Freeman, " Go big or go home"!

If you fill in the down stream side below the culvert with big rip rap (big enough that the max flow rate can't move them), that will alleviate the hole problem, no pun intended.