Pond Planning Part 1 (Initial Planning Stage)
I’ve been using the winter downtime to do quite a bit of research into farm ponds. I have to admit that I do not have a lot of practical experience with ponds, so I am working hard to get up to speed. Below is some of the information that I think is important to consider when planning a pond.
Pond Types- The first thing to decide is what type of pond you wish to build. You can build a fish pond, a frog pond, a natural pond, a koi pond, an irrigation pond, a fire block pond, a water plant pond, a duck pond, a seasonal pond, a permanent pond, or some hybrid of the aforementioned. Ideally, you can combine the attributes you wish to benefit from with the least amount of effort.
Finding the Pond Site- This can be complicated, and is somewhat dependent on the type of pond you wish to install and the size. A pond can literally be put anywhere you wish, but there are certain things to consider when picking the best spot for your needs. If you have a valley that can simply be dammed, that is typically the cheapest way to create a pond. Flat sites are cheaper than sloped sites. Positioning a pond near your garden can give your garden many benefits such as humidity and insect predators such as frogs and dragon flies. Soil type is also important if you wish to have an unlined compacted pond.
Size, shape, and depth- Based on the type of pond you wish to build and the site you wish to build it will help to determine the size, shape, and depth of your pond.
-Circular, clear, warm, and with a lined bottom would be the least productive pond arrangement.
-Frog pond should be no smaller than 12’ x 6’, 1.5’ deep. ‘=feet
-Shallow pond slopes lead to more plant and animal life
-Steep pond slopes better for weed and mosquito control
-Shape can be asymmetric with a wide bank for plants and animals, and a steep bank on the other for depth
-Bars and shoals help plant and animal life
-Islands can be a problem if too high
-Islands should be submerged in winter and early spring but exposed in summer
-1/4 acre is the minimum size for a productive fish pond, which needs 1.5-10 acres of watershed
-For a fish pond 20% of the pond should be 8’ deep
-Fish pond should average about 5’ deep, and be no deeper than 12’
Water Source & Quality- If you want a natural pond, a stream fed ponds is not ideal because it will eventually fill in with silt. For a natural pond, no inflow is better even if the pond ends up being seasonal. Seasonal ponds have specific plants and animals that thrive in that environment. The cleanest water sources are groundwater and surface water. Chemical runoff can kill vulnerable aquatic life.
Testing- Before you decide on a final pond site and pond size, it is important to test the soil to determine the viability of the pond you wish to install. You may find after testing that an alternative site may be better. Test holes should be dug 1.5’ deeper than the depth of the pond site. If you dig into waterlogged sand and gravel, a groundwater pond may be possible. If you dig into high clay content, a surface water pond is possible. Leave your test holes open through the wet and dry seasons. If your test holes do not hold water for more than a few days after wet weather then you should try a different site if you wish to have an unlined pond. You can also have soil borings analyzed to determine the soil type.
Best time to install- Summer is the best time to install a pond, in my opinion. The weather is dry, so no need to worry too much about bad weather. The ground is solid to support heavy equipment.
Equipment- It is necessary to decide what type of equipment you will need in the planning stages. If you are building a large pond, a tracked excavator is a must. You may also need a loader of dump truck if you need to move the fill far away from the pond site. Also, a sheepsfoot compacter is needed to seal the pond properly.
Soil needed for sealing- You need at least a 20% clay content to hold water. The soil bottom may need to be limed before filling if you are installing a fish pond. Some people say that a liner is necessary for a good pond. I disagree, because clay can be imported if the soil will not hold water, and even if your pond is not sealed perfectly, a seasonal pond is still very beneficial to the ecosystem. Lined ponds are higher maintenance, more expensive, and unnatural.
Dams- Dams can be cored with clay to prevent seepage. A dam should be no steeper than 3-1 on the water side. Make sure to get perennial vegetation on the dam quickly to stop erosion. Do not plant any trees on the dam as the roots can break the seal. It is a good idea to install a manual drain to drain the pond if needed.
Aeration- Aeration is really important to keep the oxygen levels up for fish. Aeration takes place with plants, wind, and flow disturbance. 5 PPM of oxygen in the water is optimal for fish, under 3 PPM they start to die. Weed filled shallow ponds are more likely to develop an oxygen deficiency than clear water, cold, open, flowing pond systems. Shade helps to maintain oxygen levels. Solar and wind commercial aerators are available, but they are expensive. Aeration may be required in small ponds, if you wish to have fish.
-A 500 gram fish is a good size for the pan, but less than 300 grams is too small.
-Fries need a netted off area to grow from predators to grow, or maybe some fingerlings, and some underwater logs to hide.
-Fish should go in right after pond is filled if you wish to stock the pond, but if you want a natural pond, just let nature take its course.
-Warm water species can develop self-sustaining populations if the pond is at least 8’ deep in PA.
Wildlife- The best wildlife ponds have no fish in them. Ducks will destroy a pond if you are feeding them.
Plants – In a natural pond, there is no need to plant anything. The plants and wildlife will show up, and the pond only takes 2-3 years to mature.
Mosquitos- Aeration and fish can keep mosquitos at bay. Avoid stagnant water to avoid mosquitos.