Creating a Lake

[Spiveyman]

Spiveyman,
That is the best motivation God ever gave man. She's a cutie. Does she have you wrapped around her finger?
hugs, Brandi

HA! Well....... kind of, but not as bad as you'd think. I'm pretty strict on her, but she likes to play me too.

Eddie, thanks for the tips... yikes! I have a question about that $$$/acre under water. If you have a long valley Vs. a short valley that you plan to flood, but the height of the water at the dam is the same, can the dam be the same size? In reading this thread I recall somewhere in the middle a discussion about that and the force being applied to the dam being a result of the depth of water, not the width of the channel. My thoughts there are that the major expense will be making the dam, but depending on where in the valley I put it, I could really varry the size of the lake but keep the dam relatively similar in size. I realize there's prep work to the bottom of the lake to make sure it holds water, but I'm not planning to "dig" the lake out, meaning I am hoping not to have to dig down 15 feet to get a 15 foot deep section. I want to flood the valley and bring the water level up the sides of the existing terrain. That's part of the reason to put it there. I have horrible soil for everything except holding water. I don't think it will take a ton of work to get the bottom rolled in. That other pond (it was there when I bought the place, not my choice of spots) is on the crest of a hill, NO run off to speak of at all, and it's almost completely full in the midst of one of the worst droughts we've had in decades. Maybe I'm naive, I like to think of it as optimistic, but I'm hoping it will be less work than you are describing. However, that's why I'm here, to figure out what is really going to happen when I start that sucker. If we're talking $60K or more to build that sucker it's going to be a loooooong while before I can pull that off.

 

[MarkV]

HA! Well....... kind of, but not as bad as you'd think. I'm pretty strict on her, but she likes to play me too.

Eddie, thanks for the tips... yikes! I have a question about that $$$/acre under water. If you have a long valley Vs. a short valley that you plan to flood, but the height of the water at the dam is the same, can the dam be the same size? In reading this thread I recall somewhere in the middle a discussion about that and the force being applied to the dam being a result of the depth of water, not the width of the channel. My thoughts there are that the major expense will be making the dam, but depending on where in the valley I put it, I could really varry the size of the lake but keep the dam relatively similar in size. I realize there's prep work to the bottom of the lake to make sure it holds water, but I'm not planning to "dig" the lake out, meaning I am hoping not to have to dig down 15 feet to get a 15 foot deep section. I want to flood the valley and bring the water level up the sides of the existing terrain. That's part of the reason to put it there. I have horrible soil for everything except holding water. I don't think it will take a ton of work to get the bottom rolled in. That other pond (it was there when I bought the place, not my choice of spots) is on the crest of a hill, NO run off to speak of at all, and it's almost completely full in the midst of one of the worst droughts we've had in decades. Maybe I'm naive, I like to think of it as optimistic, but I'm hoping it will be less work than you are describing. However, that's why I'm here, to figure out what is really going to happen when I start that sucker. If we're talking $60K or more to build that sucker it's going to be a loooooong while before I can pull that off.

Around my area pond costs run on the lower end of Eddies per acre cost estimates from what I have been told. Of course it all depends on the situation and that can vary considerably. I think you will find that the volume of water as well as the depth of the water will decide what is required when engineering the dam. All the water is weight and it all wants to continue down hill unless there is something big enough to stop it. It would be great if the government will come in and help engineer the project for you. There is much more to a dam than making a big enough pile of dirt. It needs to be built a specific way with the right material and compaction. Not the kind of job I want a contractor who is building his first pond to do. You hear a lot of stories where someone has a 25k mud hole because of a poorly designed dam. You also have some liability issues if a dam lets go and you send 10 acres of lake down stream to damage others property.

Start doing some reading at www.pondboss.com in their discussion forum. There is a lot of good information there and some friendly people.

Is it a pond or a lake? I ask a pond management person that and he told me it was whatever his clients wanted to call it. The best definition I have heard was that nature makes lakes and people make ponds.

MarkV

 

[Spiveyman]

Around my area pond costs run on the lower end of Eddies per acre cost estimates from what I have been told. Of course it all depends on the situation and that can vary considerably. I think you will find that the volume of water as well as the depth of the water will decide what is required when engineering the dam. All the water is weight and it all wants to continue down hill unless there is something big enough to stop it. It would be great if the government will come in and help engineer the project for you. There is much more to a dam than making a big enough pile of dirt. It needs to be built a specific way with the right material and compaction. Not the kind of job I want a contractor who is building his first pond to do. You hear a lot of stories where someone has a 25k mud hole because of a poorly designed dam. You also have some liability issues if a dam lets go and you send 10 acres of lake down stream to damage others property.

Start doing some reading at www.pondboss.com in their discussion forum. There is a lot of good information there and some friendly people.

Is it a pond or a lake? I ask a pond management person that and he told me it was whatever his clients wanted to call it. The best definition I have heard was that nature makes lakes and people make ponds.

MarkV

Yep, the NRCS has a pond "expert" been doing it for several decades. They will design the whole thing for me based on my goals. As for the naming, I'd say people make dams and/or wholes, nature still has to make the pond or lake. Well... that is unless you are Eddie and don't mind helping it out a bit with 40,000 hrs of pumping water!! I'm hoping nature will be kinder to me.

 

[patrick_g]

Please don't flame me but... contrary to misinformed opinion...

The force of water on a dam is proportional to the depth and it is impossible to measure a difference in that force due to the volume or distance water is backed up by the dam. One of the first things you learn about hydraulics is that when a fluid (pond or lake water) is at rest the pressure is everywhere equal (+/- the gravity head.)

In a pond or lake the pressure is PURELY a function of depth and the density of the water which for our purposes is considered a constant. The deeper the water touching part of the dam the higher the pressure. This pressure increases in a LINEAR fashion with depth.

Here is a simple water calculator:

Water Density Calculator

Temperature will vary the density of water as will various substances in solution but for our purposes we can ignore those small changes. At temperatures of interest to us water weighs about 62.37 pounds per sq ft. Dividing by 144 (number of sq inches in a sq foot) we get about 0.433 pounds for a column of water one foot high so we have 0.43 pounds per square inch for each foot of depth.

At a depth of 10 feet the pressure is 4.33 PSI. and the force on the dam is 4.33 PSI or 632.5 pounds per sq ft. At 20 ft of depth the pressure is 1265 pounds per sqft.

This is the same if the lake backed up is 100 miles long or 3 ft. This is the same if the dam is 5 ft long or 50 miles long.

If you had a situation where say you had a set of locks in the dam and you could open and close them initiating a flow "through" the dam and then shutting it off, then there would be strong dynamic considerations and you'd have to consider the weight of the moving water that you were stopping. THIS IS NOT THE CASE in impoundments with no large transient flow quenching requirements.

As to economy: I like to try to hold the greatest amount of water with the least amount of dam in width and depth. If you choose your dam site carefully you can seriously decrease the number of thousands of cubic yards you have to move which is nearly directly proportional to $ without too severely limiting your acre feet of water impounded.

Large shallow bodies of water have lots of surface area for the volume. They heat and cool more quickly and are subject to greater evaporation losses. Deeper impoundments with less surface area for the stored volume are slower to heat and cool and lose much less of a percent of their volume to evaporation.

It is easy to get carried away with surface area and not get enough depth. All this is relative of course and depends on many factors. If you have ample RELIABLE rainfall or reliable springs and or no droughts then shallow isn't as risky. Bigger surface looks more impressive until a drought if you don't have sufficient depth.

Pat

 

[Spiveyman]

...The force of water on a dam is proportional to the depth and it is impossible to measure a difference in that force due to the volume or distance water is backed up by the dam. One of the first things you learn about hydraulics is that when a fluid (pond or lake water) is at rest the pressure is everywhere equal (+/- the gravity head.)

In a pond or lake the pressure is PURELY a function of depth and the density of the water which for our purposes is considered a constant. The deeper the water touching part of the dam the higher the pressure. This pressure increases in a LINEAR fashion with depth....

...This is the same if the lake backed up is 100 miles long or 3 ft. This is the same if the dam is 5 ft long or 50 miles long.

Yep. That's what I was counting on with placing this dam and getting the most for my money and time.

Large shallow bodies of water have lots of surface area for the volume. They heat and cool more quickly and are subject to greater evaporation losses. Deeper impoundments with less surface area for the stored volume are slower to heat and cool and lose much less of a percent of their volume to evaporation.

It is easy to get carried away with surface area and not get enough depth. All this is relative of course and depends on many factors. If you have ample RELIABLE rainfall or reliable springs and or no droughts then shallow isn't as risky. Bigger surface looks more impressive until a drought if you don't have sufficient depth.

I do want sufficient depth in this lake, and do expect to have to take the surface down a bit, but also plan to take advantage of the valley there to provide much of that depth. There is a big difference between digging a 10 acre/30 ft deep lake and damming up a 26 foot deep valley that is 10 acres long. I also want max depth at the dam with some shallow-er fingers for fish habitats. What I've read here and on PondBoss so far you don't need massively deep waters for LMB - which is my favorite. This might help visualizing it. Here's a cap from Google Earth in their 3D mode of the valley. It's not detailed like an actual photo from the air, but will do. The dam would be near the viewer with the lake backing up away from you.

 

[bindian]

Eddie,
Early in this lake thread, you mentioned using a laser level to mark your water line and spillway. Can you tell me what brand and model you have? Can these be rented? The cheap ones at Lowe's don't work too far in day light.
hugs, Brandi

 

[hunterridgefarm]

Eddie,

The campground I have my RV at has a lot of nice rock work and attractive bridge made from river rock. I will be up there this weekend and if I can remember to take the camera I take a few pictures a post them next week.

I'll also take a few of there pond and culverts.

David

Eddie,

Here are the pics of the bridge and culverts.

 

[EddieWalker]

Eddie,
Early in this lake thread, you mentioned using a laser level to mark your water line and spillway. Can you tell me what brand and model you have? Can these be rented? The cheap ones at Lowe's don't work too far in day light.
hugs, Brandi

I use a Specta LL200 laser level. It's a one person kit that included a case, the tripod, laser, grade rod and receiver. I spent a very long time doing a search on ebay for it. Prices always started out good, but quickly got out of control. Since I was looking for it by doing a search, I saw every one that was for sale on ebay, not just the ones in the business section. Mine showed up in the tool area of ebay and there was some person bidding up everyones bid the second it came in. He/she wanted it so bad that he upped teh bid every time somebody else cam along with a bid. The last hour, the price was still aroudn $100. I bid on it with five minutes to go and won it.


Unlike the basic home owner models, light or brightness doesn't affect this one. Just set it up, make it level and turn everything on. The sensor does all the work. Tha laser just sends out it's signal in a total circle all around the tripod out 250 feet. With it rotateing all around, I can get a signal from it over a five hudnred foot area.

Again, you never see the lazer or any light. You just hear the receiver and can watch teh screen to see if you need to go up or down.

Hope this helps,
Eddie

 

[EddieWalker]

David,

That rock really looks great!! I can see that it was added after the bridge was built, but done so in a very nice way. Just being in that creek looks very inviting!!!!

My bridge won't be nearly as tall There will be two feet from the bottom of the bridge to the spillway. In that two feet, I'm gonna put on a dry stack, ledgestone cultured stone. It will also just be for walking across. No cars.

What will make it unique and an attraction will be my railings. When done, it should be one of those places people want to stop and take pictures. If I do this right, it will be just such a location.

Thanks again for the pics. I really like it!!!

Eddie

 

[patrick_g]

Eddie,
Early in this lake thread, you mentioned using a laser level to mark your water line and spillway. Can you tell me what brand and model you have? Can these be rented? The cheap ones at Lowe's don't work too far in day light.
hugs, Brandi

Brandi, IF you are allowed out at night you can save a lot of $ on lasers. While a contractor MUST be able to work in bright sunlight, a DIY person doing something like "shooting" a contour to see where water will back up to could do so at night and use a much less powerfuland much less expensive laser.

Just put flags out as place holders and then revisit the area in the day to better see what you have. Another downside of a cheap laser is beam divergence, i.e. spot size at a fair distance. Still, you aren't aligning a space shot so a couple inches one way or the other is no big deal.

We used an old optical transit to "shoot" grades in several places at our place and did just fine. There is no requirement to use a LASER. The Panama canal and Boulder Dam got built without them. They are convenient and are time savers for someone "in the trade" but if yo don't do this sort of thing a lot it is no big deal.

Pat