Pond Boss Forums INTRO Questions & Observations Best depth ratio for a small pond?

In a little more than a week, I should be hiring a contractor to dig me a pond. Depending on the digging conditions and how far my budget last, I am hoping to dig a 1 1/2 acre pond. I pretty much have an idea and a plan in mind, but I am unsure of the various depths ratios I should dig. I do not want weeds to take over the pond, but I do want some shallow areas for the fish to breed. I am thinking about having a shallow area of 3-4 feet and the deepest area 8 feet. I am also planning to add a couple mounds and trenches. Here are my questions. How much of the pond should be 8 feet and how much should be 3-4 feet deep or what is a good ratio between the deep areas and the shallow areas? Secondly, will the bigger bass hang out in the deeper water or do they prefer the shallow areas?

hi b2,
lots of good questions in there. just to get you a little feedback i'll take a stab at a couple.

i chose to make all my sides steep to help reduce amount of vegetation growth. you will be creating shallow bedding areas by virtue of having mounds out in the middle somewhere. elsewhere, if you want additional bed areas and shallow gradual access (from shore), i would do it in an area you can more easily (manually) remove any unwanted vegetation.

i would also choose to make a significant part (60-70%) of your pond deeper especially if you plan on aerating (otherwise fish wont use deep areas), which will ultimately give you more carrying capacity and you'll be able to withstand droughts better.

your channels and mounds will be critical to fish happiness as they love having structure with deeper water nearby.

p.s. i also hope you and contractor gave careful attention to dam construction (cored construction), and hopefully you have some idea about your watershed (i.e.need for emergency spillway?, etc.)

best of luck, keep us posted.

Dave, thanks for the advice. I did not think I would get any replies from this thread.

I am trying to get the right balance for a good fish habitat and maintain a good ratio for oxygen production. Since I live in Alabama, I do not see any need to go any deeper than 8 feet. Thank you for the great point about making the shallow area close to the shore. Yes, it would make it easier to reduce unwanted vegetation.

As for a water shed, my land is pretty flat so I am relying on annual rain. From what I read, Northern Alabama averages about 55". Hopefully, this keeps up my water level. Additionally, I will be banking up the dirt on one side of the pond; perhaps this will give me a small water shed.

I guess what I am asking, does oxygen production occur at deeper waters or in the shallow waters? Secondly, do you gain more oxygen with deeper water volume or with surface area?

Boomer,

How much land do you have? Is it possible to contour it so that you get lots of runoff? Contouring to collect runoff is quick and easy compared to digging the pond, and an excellent investment of 1-2 days work. I have 10 acres, and have all my land contoured to collect nearly every drop of rain, plus another 5a from the neighbor's land. I think it will pay off big some day.

More surface area and shallows are better for collecting oxygen by diffusion and plankton bloom than deep areas. Most plankton bloom (which produces oxygen) takes place at 0-6' level. You do need some deep holes for a reserve, however.

Are you going to have a dam, or are you digging out the entire pond? I hope you have at least a small dam, because a 1.5a dug pond is a massive, expensive project! Please keep us posted!

Based on my limited knowledge I'll try and answer yer question.......typically oxygen depletion occurs in deeper water, and oxygen production occurs in shallow water (mostly from photosynthesis of plants and phytoplankton during the day). As the plant and organic matter decays it consumes oxygen.

In the summer your pond will develop a thermocline if'n you dont aerate. As the organic matter decays below the thermocline, all the oxygen is used up and all kinds of fun smelly gasses other than oxygen are produced. Yer deep water areas will become anoxic/anaerobic (no oxygen) and toxic to fish......fish wont use water below the thermocline unless you aerate (with pump and airstones/diffusers). My guess is yer thermocline (in the absence of any aeration) would develop around 3 to 5 feet down during heat of summer.

More surface area will help keep the shallow water oxygenated above the thermocline, but wont help much with your deeper pockets of water unless you install some kind of circulation/aeration system.

o.k.....experts can help out if needed....hope that helps some.

Hello Dave and Bobad,

Thank you for the great explanations on oxygen production.

I will be building a dug pond with no dam. Maybe, I don't exactly understand the concept of a dam. If my land is flat, with no possible watershed, why do I need a dam?

The area of my land that I would be able to contour to get some type of watershed is only about 4 acres. On the west side there is paved road, the north side is my neighbors property, the east is small feeder creek, and the south is the main creek.

yer welcome. sometimes i dont know if i'm contributing anything meaningful or not, just fun to yak with you guys.

if it is a 100 % dig out, you wont need a dam per se, although i'd think you'd still need some form of spillway drainage. if you can contour out one side and utilize some slope (new slope that you created), the yellow iron wont need to be on your site as long, and you'll need some form of downhill dam on the other side which would need to be constructed safe enough to hold the weight of the water. theres trade offs.

boomer2. You have gotten good advice so far. Do a search on thermocline here. Once your pond is filled you can determine the depth of your thermocline by taking water temps at one foot depth increments from surface to bottom when the water temps hit 80F in late spring or early summer. Plan on installing mechanical bottom aeration if you want fish to inhabit the 7ft-8ft depth zone all summer.

Hello Bill, I did a search and read some of the postings for the subject thermocline. With my property being in North Alabama and my deepest area being 8 ft, will I have any problems with thermocline? From reading the thermocline postings, this seems to affect pond owners in the colder states.

I was hoping to have enough shallow areas and surface size where the oxygen and atmosphere interacts or where aquatic plants produce oxygen through photosynthesis.

I love the thought of being an active pond boss/owner but I would be happier if the pond produces good with minimal effort. I am willing to pay the extra time and money upfront if it will mean less headaches downrange. Therefore, I am hoping I am asking the right questions before I start digging next week.

Again, I appreciate all the help over the past week from all who posted in my threads. If anyone else has any extra tips on pond construction, please post it.

They occur in the south just the same. See page 20 of the linked Miss. Pond Manual. It does not cover aeration which can be a remedy to low O2.

http://msucares.com/pubs/publications/p1428.pdf

In shallow southern ponds during summer the non-O2 bottom water layer gradually expands toward the surface until in some cases only the top 3-4 feet have enough O2. If you get a couple cloudy days or a big rain which will have colder water than the pond surface waters you may get pond turnover (see the link) and have a fish kill.