How to dig a pond
Type of Ponds to Dig
Wetland Embankment Pond
• Permit(s) and engineer are required
• Most expensive pond to design, permit, construct, maintain and operate
• Can result in substantial environmental impacts
• Can create a long-term hazard to downstream life and property
Embankment Pond Benefits:
• Potential increase in water availability
Can be used to control upland erosion
Wetland Dug Pond
• Permits may be required
• Less cost than an embankment pond
• Minimal environmental impacts
• Little to no hazard to downstream life and property
Benefits of the Wetland Dug Pond:
• Less regulatory than an embankment pond
• Less time and cost to design, construct, maintain and operate
than an embankment pond
• Low Environmental impacts than an embankment pond
• No potential for catastrophic pond failure or danger to
downstream life, property or infrastructure
Upland Dug Pond
• Lowest cost in time and money
• None to few environmental impacts
• No hazard to downstream life and property
Benefits and Limitations of the Upland Dug Pond:
• Suitable construction sites may limit pond location and size
• May require supplemental water to keep pond full
Design your Pond Depth and Slope
Clay Base Soil 35% Mixture
Having a clay base helps to reduce your pond from leaking. The clay base core is illustrated to the right in red. The clay base soil mixture in the soil you would use to design your pond. The 35% clay mixture is recommended ensure leakage is unlikely or at a minimum risk. Most people hire dirt contractors to perform the work. Renting or hiring contractors can be expensive so using these guidelines should help reduce the risk of your pond or lake having a leak.
Understanding Slope & Spawning Areas
Common slope terms are 4:1, 3:1 or 2:1. For example if you have a 3:1 slope.
For every 3 feet, the elevation will drop 1 foot. Vegetation and algae thrive in shallow water. 4:1 slopes, though productive for spawning areas, lend themselves to breeding grounds for unwanted algae and vegetation. Banks in most areas should slope rapidly, 2:1 or 3:1 ratios will minimize vegetation. Shelving can be done to maximize the spawning areas. You should limit the use of 4:1 slopes. One example, is giving cattle or livestock easy access to your pond or lake. We will cover spawning areas in creating habitat and spawning areas.
Understanding Your Watershed
When figuring size, you will need to consider the amount of watershed needed to sustain your size pond or lake. It generally requires up to 100 acres of watershed per acre foot of pond storage. Keep in mind, watershed is affected by many different factors. Wooded, highly vegetated areas and certain soil types will divert or intercept rainfall. Dryer climates may need larger watersheds to maintain adequate water levels as where climates with heavier rainfall will require less acreage. Watershed should help you dictate placement of your pond or lake. Moving less dirt will save you time, money and make lake management enjoyable. Too much water will make lake management tough or near impossible. Flushing or a constant flow of your lake will hinder fertilization efforts, cause erosion problems and prohibit effective water quality treatments, when necessary. Not enough watershed can lead to an inadequate runoff. Keeping your pond or lake at a low water capacity. The NRCS can be a valuable resource in helping you determine the correct watershed and even do core samples. Normally the NRCS does core samples using the Hydrologic Method. The scale usually runs A thru D. (A) being a sandy soil and (D) being Clay.
How deep shoud I dig my pond?
Pond depth is subject to several different key factors. For example, what types of fish do you prefer. Most fish like to reside in the first 4-5 feet of water. These areas are richer in oxygen. The deeper you go into the pond the less oxygen, so with this mind 10-12 feet would be adequate.If you prefer Crappie, you should consider digging your pond at a maximum recommended depth. Crappie like going to deeper water in the warmer months as where bass and bluegill will prefer the top half of the water column. Consider having several areas in your pond or lake 12-14 feet. This should provide adequate depth during warmer months and help protect yourself from drought conditions. Tip - Ponds will silt in and you will loose depth due to leaf litter, erosion and waste. We will cover how slope can help manage your pond depth.
Should I use a Liner in my pond?
Lining your pond is a great way to maintain water levels in drought or undesirable soil conditions but here is the catch. Pond and lakes with a soil/clay base contain enzymes that help dissolve muck, waste and leaf litter. Pond liners create a buffer that does not allow this process to happen. Water quality is tough to maintain. Aeration, as well as, waste and sludge treatments and algae control products will become necessary.
Areas outside your pond or lake will affect your water quality and condition. Grassy areas between runoff and your pond will minimize the risk of erosion, over fertilizing (if you have cattle or livestock) and other contaminations that can harm your fish.
Tip – Grassy areas should be a minimum of 75 feet wide, I recommend 100 feet or more between the pond and runoff. This buffer is essential to water quality and the clarity of your lake. Keep in mind this buffer should not be manicured. Heavy, dense, grassy areas are best. You can manicure the edges of the pond or lake. Keep this in mind, these areas would best serve you and your pond or lake if they were left unmaintained to break up as much energy as possible.
Spillway and Drainage
There are several options for your primary spillway. Traditional spillways usually consist of a pipe running through the dam’s center to maintain water levels during normal or average rainfall. The pipe size is determined by watershed and the size of your pond or lake.
Other options for spillways would be surface release to bottom-siphoning systems. Bottom siphoning systems are great for ponds and lakes with fishing as the primary purpose. These systems drain water at the lower levels of the pond where the water quality is the worst, leaving the top oxygen rich layer.
Don’t forget to design an emergency spillway. This is time and money well spent. Make sure the emergency spillway goes around the dam to avoid erosion.