Pond Building 101 (Part one)

by  Ray Jordan 

Martha & I have just finished building two new ponds.  Our main pond is a 8,300 gallon koi pond the second is a 600 gallon goldfish pond/watergarden. We decided to use a pond contractor to do most of the actual work but designed and supervised the entire operation.  In the process we had many decisions to make. In part one of this article I will attempt to describe the difference between a “classic” koi pond and a “classic” water garden. Also I will try to describe a typical backyard pond that is usually a blend of these two designs. I will offer suggestions and information on pond construction materials and techniques in part two of this article next month. In this months article I want to stress the importance of knowing what you want and also what you need before you start designing and building your new pond. Also, you need to know this same information if you plan to hire a pond builder to do the work for you. 

SO, WHAT MAKES A “GOOD” POND?

This really depends on what you want a pond to do. Just like most projects there are usually compromises that need to be made. Any pond can be a good pond so long as you enjoy the result. It is really easier to describe a bad pond. In my mind a bad pond is one that requires much more work than it delivers pleasure. This usually results in abandoning the pond hobby or finally building a new pond that works for you. With all the modern technology and supplies available today you should be able to spend most of your pond time sitting and enjoying your pond versus “working” to clean the filter or other pond maintenance duties.

You need to pick the right location for your new pond. The best ponds I have seen are right next to the patio or deck and can even be viewed from inside the house. This means you can enjoy your pond more often and easier than one that requires extra effort to view. However, if you do not have ample space near your house it will need to be placed farther away. Your pond budget is another very import consideration. This will decide how large and elaborate your pond will be. If you can afford it a little extra money spent wisely up front will save lots of money and return a lot more pleasure down the road. I have never heard anyone say their pond or filter system is too large.

 I have learned most of what I know from experienced TKFGS members and reading books and watching videos that are available in our club library. I strongly urge you to become knowledgeable before you start your pond. Without question the number one reason why we lose people in this hobby are related to the frustrations of trying to cope with a poorly designed pond. You will need to be actively involved even if you hire a pond contractor.

 WHAT MAKES A GOOD KOI  POND?

A koi pond should be designed to display, grow healthy koi with a minimum of work. The focal point of a koi pond are the koi. Nothing should distract the eye from the beautiful “living jewels” of a koi pond. Since koi can grow to be quite large, up to 30 inches at maturity, a koi pond should be planned with this in mind. Yes, I have seen koi living in small shallow ponds. However, the truly memorial koi ponds show off their inhabitants to their best advantage. I suggest that serious koi ponds be at least 5,000 gallons and rectangular in shape. The pond dimensions might be twelve feet wide by fifteen feet long and averaging four feet deep. If your available space is narrow that can work also. Design a pond  eight feet wide by 22 feet long averaging four feet deep and get about the same water volume. The formula for calculating the volume of a pond that is rectangular is length X width X depth X 7.5 = gallons.  

The minimum depth should be three feet in moderate climates with a four, five, or even six foot deep end even better and necessary in the colder parts of the country. The pond’s bottom should slope towards the bottom drains at a rate of one to two inches per linear foot. For example a pond 18 feet long should slope 18 to 36 inches from the shallow part to the deepest part where one or more bottom drains are required.

 Anything much over twelve feet wide makes it very difficult to catch your fish. (Believe me you will need to catch your fish at some point) A pond twelve feet wide should have two bottom drains placed in the deep end of the pond about four feet from the pond sides and each other. Bottom drains at best will only draw water and debris from about  four feet away.

Avoid dead water spots that will occur with odd shaped ponds. You want to pull all the pond’s water volume through your filter system every 1-2 hours.  Larger ponds could be closer to two hours while smaller ponds should be about once every hour. With a koi pond your primary objective is to “keep your water clean, clear, and as healthy as possible. The main water return or waterfall should be at the shallow end and the bottom drains and a surface skimmer should be at the deeper end of the pond. You also want  water returns (jets) below the surface to help mix and rotate the water and move it towards the bottom drains and skimmer and also create a current that gives your koi exercise and promotes good growth and health.

 A round pond will require a larger overall space to hold the same water volume. However, a round pond can be the easiest to maintain. Water jets can rotate the water around the pond and help push waste towards the middle of the pond where it can be sucked down a bottom drain. It will be quite a bit harder to catch your fish in a round pond. The formula for calculating the volume of a round pond is diameter X diameter X depth X 5.9 = gallons. A fifteen-foot round pond averaging four feet deep would have a capacity of about 5,300 gallons.

 You want to create a crystal clear environment that makes it easy to see and enjoy your koi. This means your pond should be shaded to reduce the plankton type of algae that will turn your water turn green and cloudy if exposed to excess sunlight. However do not put your pond under a tree, as you will have to continually remove falling leaves, twigs, etc. Some plants and trees are poisonous to fish so be careful. You should avoid a large waterfall that would disturb the smooth surface of the pond. Remember you want a smooth mirror like surface to best view your fish. Also it is recommended to avoid plants in your koi pond.

This is a contentious point with some pond keepers. After all koi swimming gracefully among water plants is a lovely image. However, koi have a tendency to dig soil out of the planting pots and this keeps the water murky. If you try to protect your plants with netting the koi will often get scratched or entangled in the netting trying to get to the soil. Yes, people keep plants and koi together all the time. Just be prepared for some problems along the way. The best solution is to use landscaping around the pond and/or a second pond or upper level of the pond for your water plants. Another option is to have several water tub gardens sitting next to your koi pond.

 A koi pond’s surface needs to have a smooth texture that will not scrape and  cut your fish. Only use rock that is smooth and rounded. It is important not to have any nooks or crannies where your fish can get trapped. Do not have rocks or other objects extend out over the pond near the surface. Remember that koi will jump when startled. I lost fish in my original pond because it was designed to look “natural” with lots of interesting rocks. Several of my fish jumped against sharp rocks and cut themselves which sometimes resulted in an infection and ugly scar or occasionally led to a more serious infection that killed some fish.

 Because of the large size and amount of waste that koi produce you need to plan for  a adequate and efficient filter system. In fact with a koi pond the first decision you should make is what type/size of filter system are you going to use. The type of filter/s will dictate the pond plumbing design. You will need a air pump/s to supply additional aeration to support the koi and also the beneficial bacteria in the large bio filter/s. Larger equipment requirements not only increases cost for a koi pond vs a water garden but also requires a larger location. Finally depending on the type and quality of koi that you buy plan on spending $5-$20 for smaller pond quality fish up to hundreds or even thousands of dollars for larger show quality koi.

 In summary the ideal koi pond would look a lot like a swimming pool but would have a much different and larger filter/plumbing system. In fact swimming pools have been successfully converted into koi ponds. So what does a good Koi pond cost? As you might guess the range is quite large depending on the issues already listed. Certainly handy do it yourselfers can build a plastic liner koi pond for less than a thousand dollars especially if you build your own filter system. If you want a cement koi pond built by a professional you are looking at comparable prices to a commercial swimming pool job. When hiring a contractor be sure to check them out thoroughly.

 SO, What makes a good Water Garden?

A water garden is built primarily to create an environment that enhances the growth of water plants. Water Lilies are usually the focus of most water gardens. Water Lilies require direct sunlight for most of the day to insure optimum blooming and growth. Water lilies need to be pruned and fertilized and repotted regularly during the growing season. For larger ponds this means being able to get in the pond easily and wade around. For this reason most water gardens are fairly shallow from 18 inches to 30 inches in depth.  Most water plants do not like water splashing on their leaves so keep your best plants away from a splashing waterfall or fountain.

Water gardens should look like a natural pond as much as possible. Unlike a more formal koi pond a good design for an informal water garden might be oval or kidney shaped. Depending on the type of plants you want in your water garden you will want to design shelves for shallow water bog plants or perhaps multiple levels to accommodate different plant depth requirements. You want to avoid a steep slope as pots might tip over too easily and dump their potting soil into your pond. Water Gardens usually have  water features such as waterfalls or fountains to add interest. Because the emphasis is on plants there is less need for an elaborate or large filter system or plumbing. In all but the smallest water garden with only a small fish or two you will still need a filter system designed to handle your fish waste.

 An ideal water garden might be eight feet wide by sixteen feet long and two feet deep. Using the formula listed above this would give you a volume of 1,920 gallons. Being eight feet wide would make it easier to reach out and prune and fertilize your water plants without getting into the pond. Bottom drains are a nice option but not absolutely necessary in a water garden. Without a bottom drain you will need to clean the muck out of your pond on at least an annual basis. Plumbing can be much simpler and piping and filtration smaller and less expensive compared to a koi pond. 

 Water plants can be inexpensive or somewhat pricey depending on variety and availability. However, almost all water plants grow quickly and multiply like crazy. So in no time you will be looking for someone to swap or trade plants with. The variety of plants is amazing with Tropical and Hardy lilies, lotus, including day and night bloomers  plus a huge variety of other plants. You will have almost unlimited options to make your water garden unique and special. An extra bonus that water lily blooms are prolific throughout the warmer months and make wonderful flower arrangements.

 Goldfish are a much better option vs koi in a water garden. They are smaller and require less filtration and produce less waste. They are less troublesome about rooting around in your potting soil and are popular and very beautiful. A very fancy show quality goldfish can be pricey but in general pond quality goldfish are fairly inexpensive and can cost as little as a dime.  In addition to the planned inhabitants of your water garden you will get visits from special guests that will show up form time to time. Frogs, Dragonflies and a variety of other critters will discover your pond and visit it on a regular basis. 

SO, What do most  ponds look like? 

As you probably already know most ponds are neither a “pure” water garden or koi pond. Most TKFGS members ponds contain fish and plants. Therefore what would a “ideal typical pond” that would work for both fish and plants look like? Of course the options are endless but here is a design that would permit the typical pond to accommodate both fish and plants.

The typical pond would be about three feet deep and between 1000 and 3000 gallons. It would be large enough to accommodate several varieties of water lilies and other water plants. It would also have 10 – 40 fish depending on size. They could be either goldfish or small koi or a mixture of both. It would be located in part sun and part shade. It would have a water pump large enough to circulate the water in the pond through a biofilter every two hours and returned to the pond via a waterfall or a fountain. The water would be picked up at the deeper end of the pond and returned to the opposite shallower end. This would facilitate better water. The biofilter would be easy to maintain, as it has to be cleaned or back washed routinely. You would also need a small air pump to deliver additional oxygen for your fish. Most ponds have either a waterfall or a fountain to help with water circulation and create a nice visual effect.

In summary, the best type of pond for you depends on your pond interests and needs. It is a lot like transportation. Some people want a small sports car, some want a big truck, many today are choosing SUV’s. But even with SUV’s there are KIA’s and there are Lexus. Compromise is inevitable. The more you know and understand what you want to accomplish with a pond the better you can decide the best options to build into that pond. I promise you the extra effort and planning will be well worth the time and money saved later in construction.

Next month I will describe some of the construction and equipment options that can make your dream pond a reality. If anyone has a pond building experience that they would like to share with our members in the newsletter please send to Ray Jordan, 15514 Elm Park, San Antonio, TX 78247 or email rayjdiver@aol.com. Also, if you want to recommend a pond builder we would be happy to pass along that information as well.

Happy Pondering