Hi I am new to the forum and have read and learned a lot in the last few hours. So far I love the site. My wife and I are planning to dig a 4 acre pond soon and plan to put a house on "the other side" of the pond. In order to gain access to the house we either have to make an already long driveway quite a bit longer or build a land bridge through it. About 1 acre would be on one side with the remaining 3 acres on the other side w a "not sure how big yet" culvert connecting the two. About forty acres is dumping into the 1 acre side and another thirty on the 3 acre side which is where the spillway is. The land bridge would have to be approximately 250-300 feet long in order to cross the approximate 200 feet of water. I know there are several issues with something like this but would love any opinions/advice/experiences/photos/links that might be helpful. thanks

How long is the current driveway and how much longer would it have to be? I would think the costs and possible future problems would keep you from the land bridge. I'm building a house right now and to put the house with the best view of the pond I had to have a 2,000 foot driveway built complete with a concrete bridge over a creek. I didn't want to deal with a culvert.

I would think it'd be better and probably cheaper to redirect the driveway around the pond.

Talk to the NRCS to see what the 100 year flood projection is for that property to calculate gallons of water flow needed thru the bridge. That will give you some ideas on what sized culvert would be needed, and you can then figure out cost comparisons. It's better to have a culvert that is too big than to have the bridge wash away with all the vehicles at the house........

There is no driveway yet. Dealing with a clean slate and just trying to figure out the best way to do it, its all in CRP now. The driveway will be around 1800ft w the land bridge, and about another 500 w/o the land bridge. Even if I go around the pond I still have to deal with crossing the same 40 acre draw that is supplying the water. Not that money is not an issue, but I am not going to let it be the reason to not do the land bridge. I am more concerned with functionality, safety, and appearance. Will certainly tackle this issue w my NRCS guy at our next meeting. I know its difficult not seeing the property but I really appreciate all advice/opinions etc. thanks a lot guys

List your priorities. I presume that the pond will be pretty high on the list. That would mean it should be one of the least likely facets to face compromise.
Cutting a 4 acre pond in half (or quarter, as it were) would seriously compromise the aesthetic value, IMO. Not to mention that putting a earthen bridge thru it will create 500 more linear feet of shoreline and shallows that will need maintenance. Not to mention that you lose considerable water volume due to the mass and slopes of the earthen bridge.
We had to deal with a draw that I wanted a roadway across. Granted, it's not a driveway, but it could be (already supported passage of loaded tri-axel and a front loader concrete truck with about 8 yard of 'crete). Anyway, it's not brain surgery as long as the culvert is correctly sized, pitched, and correctly elevated. You are going to be looking for a close place to off-load soil waste. Your draw is screaming "fill me".
Think about every time you look out over your 4 acre pond. Draw the pic in your mind of both options. I know which one I would choose.

The way I see it you have three options. One is to build the land bridge and cut your pond in half and increase your degree of difficulty on the engineering side. Another option is to drive around the pond in what most people would call the conventional, easy method. Extra driveway expense but less intrusive to the body of water in question. The best option, IMO, is to install a "Chunnel" under the pond. There is precedent for such a project, and it only cost $17.6 Billion. This sounds way more cool to me. And if the French can do it....

I would Build the road around. It's not like your saving a whole lot of driveway by cutting across the pond. It would look very unnatural never mind the headaches involved with errosion issues.

I vote for a driveway going around the pond. What a lovely view you and your guest would be treated to everytime you come or go.

Two questions:

1) How deep is the water gonna be in the area where you are considering a land bridge?

2)Is there a source for cheap quarry stone nearby?

If the pond is not too deep in the area you are considering a landbridge and there is a good quarry nearby, you could consider building a portion of the landbridge through the middle of the pond with large quarry stone such as riprap or b-stone that would allow the water to pass through without a culvert. As long as the stone is crushed as opposed to river or creek run stone which is rounded and smooth, it could be placed at a 1.5H:1V slopes to reduce the quantity of stone needed.

Lets say you build the middle 100 ft of the landbridge out of quarry stone and the water is an average of 10 feet deep in the portion you use the quarry stone....for a 12 foot wide roadbed, you would need 100'L X 10'D X 27' effective W = 27,000 cf of stone needed or 1000 cy. 1000 cy would probably be approximately 1500 tons of crushed stone, depending on the type, size and gradation of the material.

A couple of things to keep in mind:
1) You would have to also have to buy several tons of well graded 1 1/2 or 2" crushed stone to "choke-off" the top of the big crushed stone to make a smooth base for your road bed.
2) If there is limestone available nearby at a reasonable price, consider using that rather than sandstone or other material. Limestone has a tendency to give water a pretty blue-green color; could be a nice second order benefit to your plan!!

nhc2002,

I built a land bridge to cross one corner of my property, about 150'. For me it was great as I can now cross there with equipment, etc and not need to run on the road. I'll actually be expanding it soon, raising the heigth and making it wider. It could be a good place to use up the excavated material from your pond if you have a need.

Bryan

I wanted to give a quick update and once again say thank you to all of you who took the time to give me some advice on my project. I finished the pond a couple months ago and it was full a few very short weeks later. Weather wise I was very lucky and could not have had it timed out much better. Although I did have to pump it out twice as I was trying to get the dock piers in. Overall the project went better than I expected. After much thought and research I decided to go with the land bridge. It looks a little raw right now with no landscaping etc., but I am very optimistic about its future. I found a couple semi-local land bridges, went and checked them out and loved them. They were the final straw on my decision to go with it. Best of all my wife is very pleased, so thus far I have to say its a success! BTW to all you siphon pipe lovers out there, mine kicked on for the first time last week although I was not there to see it, I know it ran. I can't wait to see it in action. Next time I am braving the rain to see it. Might add some pics of the project sometime. Again, thank you very much for the advice.