Brandi,
3ft might be a little shallow if you lose any water to evaporation. On both of my ponds, I can lose an inch to four inches in a week. In a hot, windy month, they can drop a foot if it doesn't rain. The problem with being shallow is when the water drops a foot, it will be too shallow for the fish to survive. The water will get hot and the oxygen levels will drop.
Just thought about that. Small ponds with fish in them will need oxygen introduced into the water if there's not a good, semi regular source of water coming in. Fish require oxygen to "breath" in water. In small ponds, they will use it up after awhile. How long depends on how many fish you have and how much oxygen is introduced naturally to the water.
If you see fish coming to the surface, look to see if they are gulping air. It will look like they are feeding on the surface, but there isn't any food. They are getting air for the oxygen. This is the early sign that the water is low on oxygen. Keeping the numbers of fish down and in balance for the size of your pond will help with this, but you can't stop them from breeding, so it's going to be an ongoing part of owning the pond.
In nature, when water flows over the ground, it splashes and adds oxygen to the water. Just splashing water in the pond will do this with a fountain or water fall. If you do that, then your good to go. If not, you might want to consider a system to add bubbles to the water. There are windmills that do this with a tube or pope that runs into the pond and has little holes in it. An air compressor can do this too.
The ten foot hole is just the type of contour and shape that the fish love in a pond. The worse thing that you can do is dig a smooth, "pretty" looking hole in the ground for your pond. The fish want a change of depth, drop offs and holes. The predators will go to those areas to hunt and the feeder fish will use them for hiding. When you are done digging, you will also want to add "structure" to your pond for those feeder fish to live in. Things like pallets, branches, stumps, pipes, bricks and just about any type of junk that wont' pollute the water is what the fish want and need to do well. You can go to
Pond Boss Magazine Home Page! for more ideas for structure. Some posts will show pictures, others are just discussions on it. One guy over there just finished his pond and put all sorts of satellite dishes on his pond bottom for structure. It looks like some sort of Lunar Space Station!!!
The 3:1 slope is for the angle of the inside of the dam. This angle is where you get the width of your dam so it will be strong and heavy enough to hold back the water in your pond. For the shoreline, you can go as steep as you want, or I should say, as steep as your soil will stay in place. One option is to build a retaining wall to get more depth quickly. You could go straight down at the shoreline several feet with the wall and also add more surface area of the water. It's more money, but in the long run, it's more important to build something you really want and not what you have to live with.
As for chlorine in the water, there shouldn't be a problem with your pond. What the water utilities do is add it to kill off bacteria and make it safe for humans to drink. If you have gold fish and use that water to fill their water, it will kill them if you put them in the water right away. For this purpose, you can buy other chemicals to make the water safe, but most people just buy bottled water to make their fish safe. Another thing that they could do is to just let the water sit for a few days and the chlorine will drop to a safe level for the fish naturally. The amount of chlorine in tap water is so small that it only affects the fish when "ALL" of their water is tap water and it's fresh from the tap. In your pond, most of the water will be rain water or water that has been sitting there for a period of time. Adding a few inches of tap water to several feet of existing water will not add enough chlorine to the pond to be measurable. The fish wont notice it at all as it will be diluted to a level that it's almost not even there. Then a few days later, the chlorine will be gone from the water completely. If you can get the water company to purge their lines when your pond is low, go for it. I have them do my line in August. I have a six inch water main with a 2 inch valve for purging it. They will open up that valve and let it run for about an hour. In that time, I can see the water level in my 3/4 acre pond rise an inch or two. It depends on how low I am at the time.
Every time it rains here, I'm thinking about what the water is doing and where it's going. I've gone out there in the mud many times just to see what's happening and to look for areas that I can dig down or build up the ground to get more water to my ponds. My ultimate goal is to catch 40 acres of runoff from my 68 acres. I'm getting about half of that right now. I'm also getting water off of my neighbors land, so the actual number of acres that I'm catching is fairly significant. I can't do anything to increase that part of it, but have added berms to areas that had water running off of his land and going in the wrong direction. One of those berms and a small ditch added about five acres of pasture runoff that I'm now catching. It's all a game, and one that I enjoy playing.
One thing that I'm a little concerned about are the trees that you are trying to save along your shoreline. If you are limiting the size of your pond to save those trees, keep in mind that adding a pond to them will increase the odds that they will die from wet roots when the pond fills up. Too much water is very bad for most trees, especially ones that grew up in dry soil and are not used to constant water. It takes two years to happen, but when it does, it's fairly quick. I lost two trees last year that died from this and it looks like theres at least one more thats dead, but I'm not sure until spring on that one. If it doesn't give me any leaves, it's coming out. I didn't limit my pond sized because of trees, but had hoped they would make it in spite of all the water that I was going to add to their soil. The trees that I expected to lose when building the dam and adding the soil to the tops of their root systems have all survived. It's the trees along my shoreline that I didn't add any dirt to that have died. The only explanation is that they are now shoreline trees with wet roots.
I've also found that with owning wooded, timbered land, that I don't miss any tree that I've taken out. Some were really big, beautiful, nice trees that were just in the wrong place. Now that they are gone, it's hard to remember them being there. If you took out those trees that you are trying to save now, can you make your pond bigger? Do you want it bigger? Would that be a good place for a dock?
Eddie
