Turtle Ponding. Introduction. Hi. Got an interest in having a pond for your turtle(s)? Growth in the hobby in recent years, wide-spread year-round availability and a desire to enjoy a range of species lead many keepers to get moderate-to-large collections of juveniles who eventually become a large care burden. And many of us want to offer space, natural sunlight and possibly even a natural seasonal cycle that aren’t practical indoors. Many keepers considering a pond already have indoor enclosure experience. You take a glass box (aquarium), fill 2/3’rds full, put on an external canister filter rated for 2-3x’s the tank size, add a basking platform, put a dome lamp with a heat bulb or heat emitter over the platform, lay a fluorescent strip light across the top of the tank, add a submersible heater to keep the water around 76 degrees and you’re pretty much done. Not quite, but you get the gist. By comparison, you might think ponding’s easier. Sure, you’ve got to dig a big hole, but the sun provides heat & UV-B lighting, summer time keeps the water warm, and you just need a big filter, right? No. Before we go off the deep end figuring out whether and how you want to pond, let’s get an overview. 1.) Each pond is inherently unique (esp. liner & concrete ponds). Most (except pre-formed shell-based) are custom projects. This is unlike aquariums where your 75 gallon aquarium has the same dimensions as mine. 2.) Ponds (except pre-formed shell ponds) are more about digging a huge custom hole and lining it with something (i.e.: liner or concrete) than buying a ‘box’ (like an aquarium or stock tank). 3.) Pond filtration systems are modular; the water pump, main filter and pre-filter (if any) are typically sold separately and many people mix components from different manufacturers. You will almost certainly want a UV-Clarifier (to prevent pea soup-like green water). If you’re wise and have the money, you’ll want a bottom drain (to suck crud off the bottom over time, so it doesn’t build up & rot for you to clean out later) and a settling chamber of some sort (to let solid crud settle out in a chamber outside the pond, where it’s easier to remove). You’ll be connecting the modular parts of your system with PVC pipe, flexible hose or the like, so some ‘plumbing’ work is involved. 4.) Many people have an ‘extra’ filtration circuit; they use a pond skimmer to skim off surface water & remove floating detritus (i.e.: dead leaves) before it sinks and rots. It’s hooked to another water pump, and sends water back to the pond separately from the main filter circuit return. 5.) Those hard pre-formed pond shells you see at hardware stores are typically low volume (under 300 gallons), shallow (under 2 feet deep) and have plant shelves (which give raccoons a place to sit and wading birds a place to stand while they hunt your turtles). Outdoor setups need far larger volumes than indoor, for temperature stability. It’s recommended ponds for Koi be at least 3,000 gallons, so if you hope to keep Koi with your turtles, factor that in. 6.) Many turtles love to hide and quickly ‘go wild’ in pond environments. You may seldom see some of them in a pond, and then at a distance. 7.) Despite the ‘benefits’ of ponds (i.e.: natural sunlight, large water volumes), some turtles don’t transition well for reasons unknown and can sicken, drown, etc… You may find a dead turtle after switching to a pond & never get a cause of death. 8.) Some of the larger turtle species you’d most like to pond (i.e.: cooters, big female sliders) are partially or strongly herbivorous and will eat water lilies and some other plants you want to keep. 9.) Ponding projects often end up costing a lot more than originally planned. 10.) Ponds are a lot harder to ‘move’ than aquariums. Some equipment, like the bottom drain, may be concreted in. If you rent or move often, better think about it. 11.) Turtles are escape artists and will leave your pond unless it’s secured. You need an unclimbable overhang over the pond, or wall around it. Still with me? Great! Okay, let’s talk about ponding! It’s a lot of work up front (& some thereafter), fun and addictive. *Disclaimer: Many ponds pictured in this article aren’t designed to contain turtles, but demonstrate other aspects of ponding (i.e.: types of ponds). Chapter 1: Advance Planning. Before we get into what kind of pond you want, let’s do a little advance planning. Consider these points: 1.) Tentatively draw up a rough plan on pond dimensions (length, width, depth), and consider type (water garden or koi pond), frame design (pre-formed shell, liner or concrete) and whether it’ll have an above-ground perimeter wall to raise the water level above ground. If you’re in an area with a high water table, it may be impractical to dig deep (see KoiPhen.com thread for more). 2.) Decide whether you need a filter pit. These are flat-bottomed (often with concrete slab floor and walls) holes (often rectangular) dug into the ground near a pond, so you can position some pond equipment (i.e.: settling chamber or sieve, water pump, filter) below pond water level to enable gravity-fed equipment setups rather than pump-fed setups (more about this later). You can have a gravity-fed setup without a filter pit only if your pond is at least partly above-ground. 3.) Do I rent or own my yard? If you rent, large, permanent landscape-altering features like deep in-ground concrete ponds or large above-ground concrete block-walled ponds may be disallowed. 4.) Contact your city’s Planning & Zoning Commission and ask what sort of permit you’ll need. They may treat your pond as an in-ground or above-ground swimming pool. The permit should be fairly cheap, but there’ll be regulatory hurdles (i.e.: a 6 foot fence around the pool or backyard, self-latching gates, the pool must not be with a set number of feet from utility lines, etc…). 5.) The Planning & Zoning Commission may tell you who to contact about where local utility lines run (i.e.: phone, natural gas, electric, cable). Sometimes a single agency can arrange for a number of utility workers to locate lines, and this may be free of charge to you. 6.) If you’re going to run an electrical extension out to your pond area with some power outlets (as opposed to running a couple of big outdoor extension cords to the pond equipment hoping nothing bad happens), the city might require an electrician do it or some sort of inspection. 7.) If you’ve the sorry misfortune to be the slave of a Home Owners’ Association, you’d better make sure your plan won’t violate some contractual agreement. (Warning: these contracts don’t always require them to be reasonable). 8.) Will this be a summer vacation home or a year-round setup they over-winter in, and if so, in what part of the country? It’s more critical a hibernation pond be deeper. 9.) How will you secure the pond? Whatever your views on unsupervised young children, finding one floating face-down dead in your backyard would be horrible. Some people steal turtles, and some predators are kept at bay with a large fence (i.e.: humans, stray dogs, coyotes). Raccoon will flip turtles over and eat their back legs off, herons may eat small turtles, and it’s not unknown for hawks to catch turtles. Summing it up, plan to follow this sequence: a.) Read this article, then go to www.KoiPhen.com and browse threads in the Pond Construction & Filtration section to get an overview of ponding and put together a plan for your pond. Read over at least one book on Koi ponds. b.) Start a thread at KoiPhen explaining your plan, what’s to be kept in the pond, what area/climate you’re in and what equipment you have in mind to use. c.) After substantial posting back and forth, revise your plan. d.) Speak with your Landlord or Home Owners’ Association if indicated. e.) Call your local Planning & Zoning Commission and find out what regulations are at issue and what permit you’ll need. f.) Put together a list of equipment you’ll need, and submit it to one or more reputable vendors for a bid. You might get a package discount if you buy most of your equipment from one vendor. g.) Be mindful that the vendor will likely do substantial after-the-sale advising, and quality consultation is very valuable. You’re far better off getting a good package price from an assessable, wise advisor than a great price from a vendor that only offers product, not consultation. A Word About Holes – seriously consider hiring a backhoe to excavate your pond’s main hole, preferably accompanied by a dump truck to haul off unwanted dirt. A skilled operator can make a huge hole within a few hours, instead of digging taking up your spare evenings and weekends for a couple of months. Chapter 2: Water Gardens vs. Koi Ponds. We’ll deal with the major pond types in the next chapter. First, let’s deal with the 2 major divisions in common backyard ponds; the water garden vs. the Koi pond. Watergardens – Ponds focusing on growing abundant plant life (usually some water lilies and marginals such as pickerel rush and water iris). They are usually fairly shallow (18” is fine for most water lilies), have a shallow plant shelf for marginal plant pots, have a mainly still water surface (water lilies don’t like splashing water), and due to high plant and low animal biomass have modest filtration needs (i.e.: if lily pads cover much of the surface and higher plants compete well with algae, you may not need a UV-Clarifier). Submersible water pumps are common. Water Gardens come in a variety of forms; pre-formed, liner and concrete ponds, natural-looking with irregular margins vs. ‘formal’ (i.e.: rectangular or circular) designs, as small as a hundred gallons or as large as thousands, etc… A variety of animals can be kept in Water Gardens (some show up naturally). Mosquito fish or similar small fish eat mosquito larvae, a few goldfish for vibrant color, and perhaps a few small turtles that don’t eat vegetation more rapidly than the pond can produce it (mud & musk turtles, some map turtles, possibly a painted turtle if the pond is large, softshells although they may burrow into plant pots). Shallow water gardens are vulnerable to herons and raccoon; they often rely on abundant cover and a deep section for some protection. A Water Garden may be well-suited for small, shallow-water denizens such as spotted turtles and mud turtles if your climate is appropriate to the time of year they’re out. Be warned some mud turtles may burrow on land and ‘aestivate’ for months, and you may not find them (problematic if the species can’t survive your local winters). A larger water garden may be a summer home for small species (i.e.: mud, musk, smaller painted and map turtles, etc…). A deeper water garden might suffice for overwintering some species. Cost is moderate. Koi Ponds – Ponds designed to accommodate the high space/water volume and heavy filtration demands of Koi. Koi ponds are larger (preferably at least 3,000 gallons), deeper (at least 3 feet; 4 is better, and keepers aim for 5 or 6 where convenient), and to ease maintenance and avoid having to remove the fish for periodic pond emptying & cleanup of rotting detritus, are often outfitted with bottom drains and some type of settling chamber in addition to a filter. UV-Clarifiers are recommended. Due to high-power filtration needs, external water pumps (not submersible) are greatly preferred for efficiency (lower electric bills and less current draw) and reliability over time. To insure Koi have protection from sunburn and overheating during summer, and can overwinter well-below the ice, and to prevent rapid temperature fluctuations, larger water volumes usually set at least partially in-ground are preferred. Many Koi ponds also feature a short above-ground wall to raise the water level a foot or two above-ground to enhance viewing pleasure (and provide seating). To discourage herons (great blue herons can stand in up to 30” of water) and raccoons (which sit on marginal shelves), Koi ponds are usually made at least 3’ deep with steep walls and no marginal shelf (note: turtle ponds differ). Some Koi keepers take filtration to the extreme; large, elaborate foam fractionators to reduce dissolved organic compounds, ozonators, oxidation-reduction potential monitoring, etc… You probably won’t need to go that far. Koi Ponds are a fine choice for larger basking aquatics (i.e.: sliders, cooters, painted turtles, large adult female map turtles, softshells) and musk turtles. Overwintering turtles in Koi ponds isn’t well-known in the hobby, so provision of a shallow pond section may be wise. You’ll want structure in the pond (basking platforms, plant pots and water lilies perhaps, a shallower shelf around part of the pond) so turtles can rest in the shallows (in other words, you don’t want a 5 foot deep vertical-walled ‘box’ with no options except swimming, sitting on a deep bottom or climbing out to bask). Koi Ponds are expensive, but plan right and get what you pay for. Other Ponds – There are ‘shades of grey’ between the 2 main types, such as shallower concrete ponds made without rebar or block and with gradually sloping sides. It’s more practical for me to focus on describing the 2 main types. Chapter 3: Pre-formed, Liner and Concrete Ponds. Pre-formed Pond Shells. Newbies often like pre-formed pond shells for their cookie-cutter simplicity. No questions about shape or lining. Dig a hole, line the bottom with sand, put the shell into the hole, fill in the hole around it with dirt, put in a submersible water pump and filter, fill with water, dechlorinate, and go. But they have small water volumes (typically under 300 gallons) and are shallow, so watch those water temp.s. They’re shallow enough for herons to wade in and raccoons to sit on plant shelves and hunt turtles, so they need securing (i.e.: near the house in a fenced in back yard frequently patrolled by a dog). You could build a short wooden wall around one & put a hinged screened-in wooden-framed lid over it, but it’d be less aesthetically pleasing. Nonetheless, pre-formed ponds can provide summer homes for small, shallow water aquatics (i.e.: spotted turtles, mud turtles, some musk turtles, young wood turtles, exotics like twist-neck turtles). Just don’t expect long-term housing for sliders, cooters or large collections, or plan to over-winter turtles in harsh climates. Cost: Cheap. Do-it-yourself Project: Very feasible. A variation on the pre-formed theme popular with those who can’t dig holes (i.e.: rental properties, buried lines on your site) is to use a stock tank as an ‘above-ground pre-formed pond.’ Stock tanks are sold for water live stock, and are made from a variety of things (commonly poly or metal) and sold at farm supply stores (i.e.: Rural King, Tractor Supply Co.). The Rubbermaid 300 gallon stock tank is very popular; so is the Behlen Country ~ 1,000 gallon stock tank. You forego the hassle and lawn damage of digging, lose the insulating effect of the Earth (i.e.: more over-heating risk in hot summer, colder in winter), and need to drill holes in the side above the intended water line for flood prevention in case of heavy rain (recent years have shown hurricanes can send huge downpours far inland). Liner Ponds. One of the leading pond types for the serious hobbyist today. Liner ponds let you customize your pond to most any shape or size, can be far larger than pre-formed pond shells allow, yet don’t require the construction time, cost and expertise that concrete projects do (i.e.: no footers, rebar, mortaring, curing and sealing concrete). Decent-sized liner ponds are more expensive than pre-formed but much cheaper than concrete ponds. There are several kinds of pond liner; polypropylene, polythylene, PVC, EPDM and Butyl. In the U.S., 45 mil EPDM is far and away the lead recommended liner material, whereas Butyl is comparably reputable and holds a similar position in Europe. EPDM is strong, flexible, UV-resistant and pretty easy to work with and repair. Polypropylene is a bit tougher but a good deal less flexible; it’s sometimes used for very large projects where large sheets need to be welded together for coverage. A cheaper alternative is polythylene, but it’s likewise not very flexible, is vulnerable to UV from sunlight, sheets are hard to weld together and it’s not recommended for most. I see PVC liners included in a range of lower end pond kits; it’s a decent material but less durable than EPDM. Bottom Line: In the U.S. get EPDM liner (or Butyl) and in Europe get Butyl liner. The basics of a liner pond are these; you dig a big hole, choose a rectangular liner large enough to line the pond with at least a 1’ overhang on all sides, secure the liner around the edge (i.e.: with a row of ‘coping stones’), trim to fit and fill with water. Ideally you lay down a layer of underlayment (some use old carpet for this) to protect the liner from tree roots and sharp stones. For a Koi pond, first install a bottom drain and 3 or 4” PVC line off the drain before laying down the liner. When you fill the pond, the liner will form large wrinkles (folds); you can try to make neat folds during water filling and press against the wall, but this ‘messiness’ is part of a liner pond’s look. Very steep pond walls not reinforced (i.e.: with stacked & mortared concrete block walls, or treated plywood) are subject to collapse inward (esp. if the perimeter is ringed by heavy coping stones with no footer). You might expect this with sandy soils, but clay (very hard when dry) is composed of tiny particles and can collapse when wet. You’re at highest risk when you drain the pond and there’s no in-pond water pressure pushing outward against the pond walls. Here’s AuntieSue’s thread at KoiPhen.com to give you an example of wall collapse. Calculating the amount of liner you need. Liner is sold in either pre-cut squares or rectangles (i.e.: 20’ x 24’) or per foot length with a set width. So you’ll need to buy it according to a given length and width (warning: Internet liner prices look cheap, but shipping is outrageous because liner is very heavy). Each is calculated separately, but the same way. Find the point in your planned pond hole that’s the greatest width. Now, measure the distance down the wall, across the bottom to the far wall, and up that wall, then add 2 feet (so there’s at least 1 foot of overhang at both ends). That’s the minimum width of liner, and since they say no plan survives contact with the enemy, I suggest you add at least 2 more feet. Above-Ground Liner Ponds Many people like having ponds rise 1 to 2 feet above ground level, providing a place to sit, bringing the pond closer to your face and making it easier to design a setup using gravity-fed filtration equipment (which has advantages over pump-fed). That wall can be made of most anything very strong and durable; a mortared concrete block wall with rebar & wet concrete in the holes, set on a concrete footer base around the pond edge for support, is a classic method. On a rental property where disassembly potential was important, we built above-ground walls by stacking 6”x6”x16’ treated wooden posts, alternating the overlapping ends at the corners, then drilling holes at the corners and along the walls, and dropping rebar strips through the holes to lock the posts together into a strong wall. So liner ponds are often used to make ‘hybrid ponds’ by borrowing techniques from concrete ponds (i.e.: the block wall). Cost: Moderate. Do-it-yourself Project: Very feasible, unless you want above-ground raised walls (which can be DIY, but it’s more challenging to work with mortar on concrete block walls and lay a concrete footer). Concrete Ponds. Concrete ponds offer the greatest strength & durability of the common pond types, and in exchange require plenty of money, time, expertise and sheer labor, and are much more rigidly inflexible than a liner pond (i.e.: revising the pond later, adding a bottom drain, deciding to install TPRs, these things are much harder with concrete ponds than liner ponds). Unless you or a good friend are knowledgeable about working with concrete construction, you’ll likely hire a contractor for a concrete pond. There are different ways to make one. Watergarden Style – Imagine a fairly shallow pond perhaps 18” to 3’ deep, with fairly gradually sloping walls, dug into the earth. Once the hole is dug the maker mixes, pours, smears and smooths out a thick layer of wet concrete over the ground, coating the pond walls. This is allowed to dry over time, later cured and perhaps ultimately sealed with a commercial sealant like Pond Armor® or DryLok® (note: Steve Joneli hasn’t had good results using DryLok on concrete block). This type of pond is used by some turtle keepers. The concrete usually isn’t reinforced by a rebar framework inset into the wet concrete during construction, so it’s not as resistant to cracking and fracturing with ground shifts (so it needs to be deeper than the local frost line). Because wet concrete is basically ‘slopped on,’ the walls have to slope gradually so it doesn’t run off before it hardens. For another take on Concrete (and other pond types), see this article by Wendy Kennedy. Cost: Moderate. Do-it-yourself Project: Fairly feasible, but expect to read up on concrete curing and sealing, and making concrete walls is a lot more work than unrolling EPDM liner. Koi Pond Style – One of the most common techniques is to lay a concrete slab for the bottom (after your bottom drain is in place, so the concrete holds it), then build a concrete block wall around the perimeter, with steel rebar in the concrete block holes and the blocks ‘staggered’ (so each covers half of each of the two beneath it); the blocks are mortared together, the rebar put in and wet concrete poured into the holes with the rebar to meld it with the wall. Rebar is also laid in the bottom of the pond before the wet concrete for the slab is poured, to reinforce it. Some people use surface-bonding cement instead of mortar. Another technique involves the same process of installing the bottom drain (including exit PVC pipe and (if an air diffuser is on the bottom drain) air PVC line), then laying down strips of rebar, then pouring wet concrete to cover the rebar and form a concrete slab for the pond base. But instead of using concrete blocks, you put strips of rebar against the pond walls, stand sheets of plywood up parallel with the pond walls, fix them in place, and pour wet concrete between the plywood and pond walls. These plywood sheets are called forms when used this way, because they hold the wet concrete in place until it dries, assuming the proper form (vertical walls). When working with concrete walls, you need footers. A footer is a narrow concrete slab (i.e.: 8” thick and 12” wide) constructed to be the base of a concrete wall, so the wall doesn’t crack/fracture as the ground beneath it shifts as seasons/temperatures change. The Koi Pond style concrete pond requires consideration of geographical area and local climate to determine depth needed and get an idea of what size footers &/or bottom slab to install, and to decide how much & what size rebar to use. Professional contractors often have equipment to simplify constructions, such as sprayable forms of concrete (i.e.: Gunite and Shotcrete). Cost: Expensive. Do-it-yourself Project: Not feasible (unless you’re really up on constructor, or highly driven, ‘handy’ and have very good advisors). Spray On Liner Ponds Combining the initial versatility of a liner pond (any size, any shape) with wrinkle/fold-free puncture-resistant strength somewhat like a rigid plastic pond shell, these ponds entail digging a large hole like you’d use for a liner pond, but instead of liner, you pay a contractor to come in and spray your pond walls with a liquid that dries into a solid, variably flexible coating on the pond walls. Some forms can be done as DIY projects, but most aren’t. This route tends to be very expensive but many ponders are pleased with the wrinkle-free (unlike liner) smooth (unlike concrete) dark pond coating, customized to their own large pond (unlike a rigid pre-formed shell). While these account for a small minority of ponds, cost is a big drawback. Spray-on coatings often require structural wall support (in other words, underlying walls (like concrete) or a support layer (like geotextile fabric – ideally woven type, not the type used as pond underlayment) in place, and use the spray-on product as a coating), but not necessarily thick, rigid walls (i.e.: you can use geotextile fabric in your dirt hole, & spray polyurea over that). Polyurea is a common form (not DIY) – one popular brand is Pond Shield FSP (FSP = Fish Safe Polyurea); Sani-tred® is potentially DIY, but usage can be challenging.

Turtle Ponding.

Introduction.

Hi. Got an interest in having a pond for your turtle(s)? Growth in the hobby in recent years, wide-spread year-round availability and a desire to enjoy a range of species lead many keepers to get moderate-to-large collections of juveniles who eventually become a large care burden. And many of us want to offer space, natural sunlight and possibly even a natural seasonal cycle that aren’t practical indoors.

Many keepers considering a pond already have indoor enclosure experience. You take a glass box (aquarium), fill 2/3’rds full, put on an external canister filter rated for 2-3x’s the tank size, add a basking platform, put a dome lamp with a heat bulb or heat emitter over the platform, lay a fluorescent strip light across the top of the tank, add a submersible heater to keep the water around 76 degrees and you’re pretty much done. Not quite, but you get the gist.

By comparison, you might think ponding’s easier. Sure, you’ve got to dig a big hole, but the sun provides heat & UV-B lighting, summer time keeps the water warm, and you just need a big filter, right?

No. Before we go off the deep end figuring out whether and how you want to pond, let’s get an overview.

1.) Each pond is inherently unique (esp. liner & concrete ponds). Most (except pre-formed shell-based) are custom projects. This is unlike aquariums where your 75 gallon aquarium has the same dimensions as mine.

2.) Ponds (except pre-formed shell ponds) are more about digging a huge custom hole and lining it with something (i.e.: liner or concrete) than buying a ‘box’ (like an aquarium or stock tank).

3.) Pond filtration systems are modular; the water pump, main filter and pre-filter (if any) are typically sold separately and many people mix components from different manufacturers. You will almost certainly want a UV-Clarifier (to prevent pea soup-like green water). If you’re wise and have the money, you’ll want a bottom drain (to suck crud off the bottom over time, so it doesn’t build up & rot for you to clean out later) and a settling chamber of some sort (to let solid crud settle out in a chamber outside the pond, where it’s easier to remove). You’ll be connecting the modular parts of your system with PVC pipe, flexible hose or the like, so some ‘plumbing’ work is involved.

4.) Many people have an ‘extra’ filtration circuit; they use a pond skimmer to skim off surface water & remove floating detritus (i.e.: dead leaves) before it sinks and rots. It’s hooked to another water pump, and sends water back to the pond separately from the main filter circuit return.

5.) Those hard pre-formed pond shells you see at hardware stores are typically low volume (under 300 gallons), shallow (under 2 feet deep) and have plant shelves (which give raccoons a place to sit and wading birds a place to stand while they hunt your turtles). Outdoor setups need far larger volumes than indoor, for temperature stability. It’s recommended ponds for Koi be at least 3,000 gallons, so if you hope to keep Koi with your turtles, factor that in.

6.) Many turtles love to hide and quickly ‘go wild’ in pond environments. You may seldom see some of them in a pond, and then at a distance.

7.) Despite the ‘benefits’ of ponds (i.e.: natural sunlight, large water volumes), some turtles don’t transition well for reasons unknown and can sicken, drown, etc… You may find a dead turtle after switching to a pond & never get a cause of death.

8.) Some of the larger turtle species you’d most like to pond (i.e.: cooters, big female sliders) are partially or strongly herbivorous and will eat water lilies and some other plants you want to keep.

9.) Ponding projects often end up costing a lot more than originally planned.

10.) Ponds are a lot harder to ‘move’ than aquariums. Some equipment, like the bottom drain, may be concreted in. If you rent or move often, better think about it.

11.) Turtles are escape artists and will leave your pond unless it’s secured. You need an unclimbable overhang over the pond, or wall around it.

Still with me? Great! Okay, let’s talk about ponding! It’s a lot of work up front (& some thereafter), fun and addictive. *Disclaimer: Many ponds pictured in this article aren’t designed to contain turtles, but demonstrate other aspects of ponding (i.e.: types of ponds).

Chapter 1: Advance Planning.

Before we get into what kind of pond you want, let’s do a little advance planning. Consider these points:

1.) Tentatively draw up a rough plan on pond dimensions (length, width, depth), and consider type (water garden or koi pond), frame design (pre-formed shell, liner or concrete) and whether it’ll have an above-ground perimeter wall to raise the water level above ground. If you’re in an area with a high water table, it may be impractical to dig deep (see KoiPhen.com thread for more).

2.) Decide whether you need a filter pit. These are flat-bottomed (often with concrete slab floor and walls) holes (often rectangular) dug into the ground near a pond, so you can position some pond equipment (i.e.: settling chamber or sieve, water pump, filter) below pond water level to enable gravity-fed equipment setups rather than pump-fed setups (more about this later). You can have a gravity-fed setup without a filter pit only if your pond is at least partly above-ground.

3.) Do I rent or own my yard? If you rent, large, permanent landscape-altering features like deep in-ground concrete ponds or large above-ground concrete block-walled ponds may be disallowed.

4.) Contact your city’s Planning & Zoning Commission and ask what sort of permit you’ll need. They may treat your pond as an in-ground or above-ground swimming pool. The permit should be fairly cheap, but there’ll be regulatory hurdles (i.e.: a 6 foot fence around the pool or backyard, self-latching gates, the pool must not be with a set number of feet from utility lines, etc…).

5.) The Planning & Zoning Commission may tell you who to contact about where local utility lines run (i.e.: phone, natural gas, electric, cable). Sometimes a single agency can arrange for a number of utility workers to locate lines, and this may be free of charge to you.

6.) If you’re going to run an electrical extension out to your pond area with some power outlets (as opposed to running a couple of big outdoor extension cords to the pond equipment hoping nothing bad happens), the city might require an electrician do it or some sort of inspection.

7.) If you’ve the sorry misfortune to be the slave of a Home Owners’ Association, you’d better make sure your plan won’t violate some contractual agreement. (Warning: these contracts don’t always require them to be reasonable).

8.) Will this be a summer vacation home or a year-round setup they over-winter in, and if so, in what part of the country? It’s more critical a hibernation pond be deeper.

9.) How will you secure the pond? Whatever your views on unsupervised young children, finding one floating face-down dead in your backyard would be horrible. Some people steal turtles, and some predators are kept at bay with a large fence (i.e.: humans, stray dogs, coyotes). Raccoon will flip turtles over and eat their back legs off, herons may eat small turtles, and it’s not unknown for hawks to catch turtles.

Summing it up, plan to follow this sequence:

a.) Read this article, then go to www.KoiPhen.com and browse threads in the Pond Construction & Filtration section to get an overview of ponding and put together a plan for your pond. Read over at least one book on Koi ponds.

b.) Start a thread at KoiPhen explaining your plan, what’s to be kept in the pond, what area/climate you’re in and what equipment you have in mind to use.

c.) After substantial posting back and forth, revise your plan.

d.) Speak with your Landlord or Home Owners’ Association if indicated.

e.) Call your local Planning & Zoning Commission and find out what regulations are at issue and what permit you’ll need.

f.) Put together a list of equipment you’ll need, and submit it to one or more reputable vendors for a bid. You might get a package discount if you buy most of your equipment from one vendor.

g.) Be mindful that the vendor will likely do substantial after-the-sale advising, and quality consultation is very valuable. You’re far better off getting a good package price from an assessable, wise advisor than a great price from a vendor that only offers product, not consultation.

A Word About Holes – seriously consider hiring a backhoe to excavate your pond’s main hole, preferably accompanied by a dump truck to haul off unwanted dirt. A skilled operator can make a huge hole within a few hours, instead of digging taking up your spare evenings and weekends for a couple of months.

Chapter 2: Water Gardens vs. Koi Ponds.

We’ll deal with the major pond types in the next chapter. First, let’s deal with the 2 major divisions in common backyard ponds; the water garden vs. the Koi pond.

Watergardens – Ponds focusing on growing abundant plant life (usually some water lilies and marginals such as pickerel rush and water iris). They are usually fairly shallow (18” is fine for most water lilies), have a shallow plant shelf for marginal plant pots, have a mainly still water surface (water lilies don’t like splashing water), and due to high plant and low animal biomass have modest filtration needs (i.e.: if lily pads cover much of the surface and higher plants compete well with algae, you may not need a UV-Clarifier). Submersible water pumps are common. Water Gardens come in a variety of forms; pre-formed, liner and concrete ponds, natural-looking with irregular margins vs. ‘formal’ (i.e.: rectangular or circular) designs, as small as a hundred gallons or as large as thousands, etc…

A variety of animals can be kept in Water Gardens (some show up naturally). Mosquito fish or similar small fish eat mosquito larvae, a few goldfish for vibrant color, and perhaps a few small turtles that don’t eat vegetation more rapidly than the pond can produce it (mud & musk turtles, some map turtles, possibly a painted turtle if the pond is large, softshells although they may burrow into plant pots).

Shallow water gardens are vulnerable to herons and raccoon; they often rely on abundant cover and a deep section for some protection.

A Water Garden may be well-suited for small, shallow-water denizens such as spotted turtles and mud turtles if your climate is appropriate to the time of year they’re out. Be warned some mud turtles may burrow on land and ‘aestivate’ for months, and you may not find them (problematic if the species can’t survive your local winters). A larger water garden may be a summer home for small species (i.e.: mud, musk, smaller painted and map turtles, etc…). A deeper water garden might suffice for overwintering some species.

Cost is moderate.

Koi Ponds – Ponds designed to accommodate the high space/water volume and heavy filtration demands of Koi. Koi ponds are larger (preferably at least 3,000 gallons), deeper (at least 3 feet; 4 is better, and keepers aim for 5 or 6 where convenient), and to ease maintenance and avoid having to remove the fish for periodic pond emptying & cleanup of rotting detritus, are often outfitted with bottom drains and some type of settling chamber in addition to a filter. UV-Clarifiers are recommended. Due to high-power filtration needs, external water pumps (not submersible) are greatly preferred for efficiency (lower electric bills and less current draw) and reliability over time.

To insure Koi have protection from sunburn and overheating during summer, and can overwinter well-below the ice, and to prevent rapid temperature fluctuations, larger water volumes usually set at least partially in-ground are preferred. Many Koi ponds also feature a short above-ground wall to raise the water level a foot or two above-ground to enhance viewing pleasure (and provide seating).

To discourage herons (great blue herons can stand in up to 30” of water) and raccoons (which sit on marginal shelves), Koi ponds are usually made at least 3’ deep with steep walls and no marginal shelf (note: turtle ponds differ).

Some Koi keepers take filtration to the extreme; large, elaborate foam fractionators to reduce dissolved organic compounds, ozonators, oxidation-reduction potential monitoring, etc… You probably won’t need to go that far.

Koi Ponds are a fine choice for larger basking aquatics (i.e.: sliders, cooters, painted turtles, large adult female map turtles, softshells) and musk turtles. Overwintering turtles in Koi ponds isn’t well-known in the hobby, so provision of a shallow pond section may be wise. You’ll want structure in the pond (basking platforms, plant pots and water lilies perhaps, a shallower shelf around part of the pond) so turtles can rest in the shallows (in other words, you don’t want a 5 foot deep vertical-walled ‘box’ with no options except swimming, sitting on a deep bottom or climbing out to bask).

Koi Ponds are expensive, but plan right and get what you pay for.

Other Ponds – There are ‘shades of grey’ between the 2 main types, such as shallower concrete ponds made without rebar or block and with gradually sloping sides. It’s more practical for me to focus on describing the 2 main types.

Chapter 3: Pre-formed, Liner and Concrete Ponds.

Pre-formed Pond Shells.

Newbies often like pre-formed pond shells for their cookie-cutter simplicity. No questions about shape or lining. Dig a hole, line the bottom with sand, put the shell into the hole, fill in the hole around it with dirt, put in a submersible water pump and filter, fill with water, dechlorinate, and go.

But they have small water volumes (typically under 300 gallons) and are shallow, so watch those water temp.s. They’re shallow enough for herons to wade in and raccoons to sit on plant shelves and hunt turtles, so they need securing (i.e.: near the house in a fenced in back yard frequently patrolled by a dog). You could build a short wooden wall around one & put a hinged screened-in wooden-framed lid over it, but it’d be less aesthetically pleasing.

Nonetheless, pre-formed ponds can provide summer homes for small, shallow water aquatics (i.e.: spotted turtles, mud turtles, some musk turtles, young wood turtles, exotics like twist-neck turtles). Just don’t expect long-term housing for sliders, cooters or large collections, or plan to over-winter turtles in harsh climates.

Cost: Cheap.

Do-it-yourself Project: Very feasible.

A variation on the pre-formed theme popular with those who can’t dig holes (i.e.: rental properties, buried lines on your site) is to use a stock tank as an ‘above-ground pre-formed pond.’ Stock tanks are sold for water live stock, and are made from a variety of things (commonly poly or metal) and sold at farm supply stores (i.e.: Rural King, Tractor Supply Co.). The Rubbermaid 300 gallon stock tank is very popular; so is the Behlen Country ~ 1,000 gallon stock tank. You forego the hassle and lawn damage of digging, lose the insulating effect of the Earth (i.e.: more over-heating risk in hot summer, colder in winter), and need to drill holes in the side above the intended water line for flood prevention in case of heavy rain (recent years have shown hurricanes can send huge downpours far inland).

Liner Ponds.

One of the leading pond types for the serious hobbyist today. Liner ponds let you customize your pond to most any shape or size, can be far larger than pre-formed pond shells allow, yet don’t require the construction time, cost and expertise that concrete projects do (i.e.: no footers, rebar, mortaring, curing and sealing concrete). Decent-sized liner ponds are more expensive than pre-formed but much cheaper than concrete ponds.

There are several kinds of pond liner; polypropylene, polythylene, PVC, EPDM and Butyl. In the U.S., 45 mil EPDM is far and away the lead recommended liner material, whereas Butyl is comparably reputable and holds a similar position in Europe. EPDM is strong, flexible, UV-resistant and pretty easy to work with and repair. Polypropylene is a bit tougher but a good deal less flexible; it’s sometimes used for very large projects where large sheets need to be welded together for coverage. A cheaper alternative is polythylene, but it’s likewise not very flexible, is vulnerable to UV from sunlight, sheets are hard to weld together and it’s not recommended for most. I see PVC liners included in a range of lower end pond kits; it’s a decent material but less durable than EPDM.

Bottom Line: In the U.S. get EPDM liner (or Butyl) and in Europe get Butyl liner.

The basics of a liner pond are these; you dig a big hole, choose a rectangular liner large enough to line the pond with at least a 1’ overhang on all sides, secure the liner around the edge (i.e.: with a row of ‘coping stones’), trim to fit and fill with water. Ideally you lay down a layer of underlayment (some use old carpet for this) to protect the liner from tree roots and sharp stones. For a Koi pond, first install a bottom drain and 3 or 4” PVC line off the drain before laying down the liner. When you fill the pond, the liner will form large wrinkles (folds); you can try to make neat folds during water filling and press against the wall, but this ‘messiness’ is part of a liner pond’s look.

Very steep pond walls not reinforced (i.e.: with stacked & mortared concrete block walls, or treated plywood) are subject to collapse inward (esp. if the perimeter is ringed by heavy coping stones with no footer). You might expect this with sandy soils, but clay (very hard when dry) is composed of tiny particles and can collapse when wet. You’re at highest risk when you drain the pond and there’s no in-pond water pressure pushing outward against the pond walls. Here’s AuntieSue’s thread at KoiPhen.com to give you an example of wall collapse.

Calculating the amount of liner you need.

Liner is sold in either pre-cut squares or rectangles (i.e.: 20’ x 24’) or per foot length with a set width. So you’ll need to buy it according to a given length and width (warning: Internet liner prices look cheap, but shipping is outrageous because liner is very heavy). Each is calculated separately, but the same way.

Find the point in your planned pond hole that’s the greatest width. Now, measure the distance down the wall, across the bottom to the far wall, and up that wall, then add 2 feet (so there’s at least 1 foot of overhang at both ends). That’s the minimum width of liner, and since they say no plan survives contact with the enemy, I suggest you add at least 2 more feet.

Above-Ground Liner Ponds

Many people like having ponds rise 1 to 2 feet above ground level, providing a place to sit, bringing the pond closer to your face and making it easier to design a setup using gravity-fed filtration equipment (which has advantages over pump-fed). That wall can be made of most anything very strong and durable; a mortared concrete block wall with rebar & wet concrete in the holes, set on a concrete footer base around the pond edge for support, is a classic method. On a rental property where disassembly potential was important, we built above-ground walls by stacking 6”x6”x16’ treated wooden posts, alternating the overlapping ends at the corners, then drilling holes at the corners and along the walls, and dropping rebar strips through the holes to lock the posts together into a strong wall. So liner ponds are often used to make ‘hybrid ponds’ by borrowing techniques from concrete ponds (i.e.: the block wall).

Cost: Moderate.

Do-it-yourself Project: Very feasible, unless you want above-ground raised walls (which can be DIY, but it’s more challenging to work with mortar on concrete block walls and lay a concrete footer).

Concrete Ponds.

Concrete ponds offer the greatest strength & durability of the common pond types, and in exchange require plenty of money, time, expertise and sheer labor, and are much more rigidly inflexible than a liner pond (i.e.: revising the pond later, adding a bottom drain, deciding to install TPRs, these things are much harder with concrete ponds than liner ponds). Unless you or a good friend are knowledgeable about working with concrete construction, you’ll likely hire a contractor for a concrete pond. There are different ways to make one.

Watergarden Style – Imagine a fairly shallow pond perhaps 18” to 3’ deep, with fairly gradually sloping walls, dug into the earth. Once the hole is dug the maker mixes, pours, smears and smooths out a thick layer of wet concrete over the ground, coating the pond walls. This is allowed to dry over time, later cured and perhaps ultimately sealed with a commercial sealant like Pond Armor® or DryLok® (note: Steve Joneli hasn’t had good results using DryLok on concrete block).

This type of pond is used by some turtle keepers. The concrete usually isn’t reinforced by a rebar framework inset into the wet concrete during construction, so it’s not as resistant to cracking and fracturing with ground shifts (so it needs to be deeper than the local frost line). Because wet concrete is basically ‘slopped on,’ the walls have to slope gradually so it doesn’t run off before it hardens. For another take on Concrete (and other pond types), see this article by Wendy Kennedy.

Cost: Moderate.

Do-it-yourself Project: Fairly feasible, but expect to read up on concrete curing and sealing, and making concrete walls is a lot more work than unrolling EPDM liner.

Koi Pond Style – One of the most common techniques is to lay a concrete slab for the bottom (after your bottom drain is in place, so the concrete holds it), then build a concrete block wall around the perimeter, with steel rebar in the concrete block holes and the blocks ‘staggered’ (so each covers half of each of the two beneath it); the blocks are mortared together, the rebar put in and wet concrete poured into the holes with the rebar to meld it with the wall. Rebar is also laid in the bottom of the pond before the wet concrete for the slab is poured, to reinforce it. Some people use surface-bonding cement instead of mortar.

Another technique involves the same process of installing the bottom drain (including exit PVC pipe and (if an air diffuser is on the bottom drain) air PVC line), then laying down strips of rebar, then pouring wet concrete to cover the rebar and form a concrete slab for the pond base. But instead of using concrete blocks, you put strips of rebar against the pond walls, stand sheets of plywood up parallel with the pond walls, fix them in place, and pour wet concrete between the plywood and pond walls. These plywood sheets are called forms when used this way, because they hold the wet concrete in place until it dries, assuming the proper form (vertical walls).

When working with concrete walls, you need footers. A footer is a narrow concrete slab (i.e.: 8” thick and 12” wide) constructed to be the base of a concrete wall, so the wall doesn’t crack/fracture as the ground beneath it shifts as seasons/temperatures change.

The Koi Pond style concrete pond requires consideration of geographical area and local climate to determine depth needed and get an idea of what size footers &/or bottom slab to install, and to decide how much & what size rebar to use. Professional contractors often have equipment to simplify constructions, such as sprayable forms of concrete (i.e.: Gunite and Shotcrete).

Cost: Expensive.

Do-it-yourself Project: Not feasible (unless you’re really up on constructor, or highly driven, ‘handy’ and have very good advisors).

Spray On Liner Ponds

Combining the initial versatility of a liner pond (any size, any shape) with wrinkle/fold-free puncture-resistant strength somewhat like a rigid plastic pond shell, these ponds entail digging a large hole like you’d use for a liner pond, but instead of liner, you pay a contractor to come in and spray your pond walls with a liquid that dries into a solid, variably flexible coating on the pond walls. Some forms can be done as DIY projects, but most aren’t.

This route tends to be very expensive but many ponders are pleased with the wrinkle-free (unlike liner) smooth (unlike concrete) dark pond coating, customized to their own large pond (unlike a rigid pre-formed shell). While these account for a small minority of ponds, cost is a big drawback. Spray-on coatings often require structural wall support (in other words, underlying walls (like concrete) or a support layer (like geotextile fabric – ideally woven type, not the type used as pond underlayment) in place, and use the spray-on product as a coating), but not necessarily thick, rigid walls (i.e.: you can use geotextile fabric in your dirt hole, & spray polyurea over that).

Polyurea is a common form (not DIY) – one popular brand is Pond Shield FSP (FSP = Fish Safe Polyurea); Sani-tred® is potentially DIY, but usage can be challenging.