Zoo and aquarium aquatic habitats are some of the most challenging to design. These features often include structural panels that need to hold back thousands of pounds of water so guests can watch what’s going on under the surface. But that’s far from the only consideration needed for water in exhibits. Containment in general, from preventing leaks to maintaining the correct water level, is a challenge throughout each enclosure. Designing enclosures and habitats with flexible liner installation in mind makes it much easier to secure the water, whether it’s a few hundred gallons, for a small pond, or millions of gallons for fish and marine mammals.
Partial to Total Water Coverage
First, the amount of habitat covered fully in water definitely determines the extensiveness of lining and containment measures. Not only do fully submerged habitats, like aquariums, tend to hold greater volumes of water than those with limited water features, the extra amount of surface area covered by water also increases opportunities for leaks. Each extra square foot of concrete or soil exposed to a constant supply of water provides a chance for water loss or flooding elsewhere in the facility. The more water in an enclosure or habitat, the better the liner needs to be that contains it. Of course, even small ponds and decorative streams flowing through otherwise dry habitats need lining too. They just tend to benefit from lighter and thinner liners since these features aren’t holding back millions of gallons at a time.
Seepage and Leaking
Since concrete and cement are widely used for shaping and reinforcing enclosures when designing custom naturalistic habitats, it’s a common assumption that it’s also the best material for lining the enclosure. For many years, zoos primarily coated these cement and concrete fixtures with a brush-on sealant. These sealants only last a few years before starting to leak, especially in saltwater enclosures and those exposed to the sun. This leads to expensive draining for recoating, which can stress the inhabitants of the enclosure as they’re moved in and out. Installing impermeable, long-lasting, flexible liners, made from a material like RPE, is a much better choice. The liner is easily installed underneath other material so it is not visible in the habitat, making it a secret barrier against leaks and water loss that doesn’t need the constant attention that concrete sealant requires.
What Animals Most Commonly Need Aquatic Habitats?
Aside from the obvious choices like fish and marine mammals, many of the animals commonly found in zoos benefit from at least partially aquatic habitats. Healthy and clean water features are essential or recommended for animals like:
- Hippos, capybaras, otters, muskrats, and many other mammals that spend part of their lives underwater
- Lions, gorillas, and other animals kept in social groups that act out important behaviors at watering holes
- Penguins and other wading or marine birds like flamingos and albatrosses
- Reptiles, snakes, and other amphibians that must bathe to drink properly, even if they spend most of their time out of the water
- Bears of all kinds, since these animals in particular can’t stay healthy or clean without occasional bathing.
Almost all zoo enclosures can benefit from at least a small natural water feature to encourage healthy drinking and bathing habits in animals. Of course, these ponds and streams are tricky to keep clean and sanitary without a proper polymer liner at the bottom to scrub out muck when necessary.
Moats for Containment and Animal Control
Moats are the next most important water feature found in zoo enclosures and habitats. They’re not generally designed for the animal’s use but rather to keep them contained without tall fencing that could block the view. Some animals need to be kept away from even the best fencing or glass, so a moat adds distance without obscuring the view. These moats can also be used for managing surface runoff that falls into an enclosure so there are no flooding issues. Directing all the rainfall into a pond or other water feature could cause it to become cloudy or algae filled. Moats are better equipped to deal with runoff since they’re less sensitive and tend to be larger due to the need to surround the enclosure. Zoo enclosure moats should always be lined to prevent leaking and allow for pumping as needed. Even the largest trenches can end up overflowing during a heavy rainfall event, so lined moats can function as an essential flood protection system by allowing for rapid pumping.
Algae and Mosquito Control
All water features exposed to the outdoors, even those being used daily by animals and fish, run the risk of growing algae and mosquitoes. Mosquitoes are particularly problematic in the warmer parts of the country where they may spread disease among the zoo animals and even the patrons visiting. Yet, with the animals swimming and bathing in and drinking the water, it’s not always easy to just add pesticides or algaecides to control these problems. The water features must be designed to tackle the issues through a combination of water circulation, water quality control, and animal or fish-safe treatment as necessary. Using an impermeable liner, at the bottom of the water feature, is a great start because it allows for thorough cleaning to control nutrient levels that trigger algae growth.
Maintaining High Water Quality and Clarity
Small ponds and water features designed only for animals to drink from and bathe in may only need good water quality but exhibits where guests expect to see into the water also need crystal clarity. Murky water or bits of visible debris can be acceptable only if guests aren’t trying to look through it to see the animals. While perfectly healthy and high-quality water often looks that way, zoos and aquariums must spend the extra effort on clarifying the water further for visibility and visual appeal. This makes it absolutely necessary to use durable liners in all aquatic habitats. Without a liner of some kind, it’s all too easy for muck accumulating on the bottom to get stirred up each time an animal gets in or out of the water.
Open vs Fully Enclosed Aquatic Habitats
Fully enclosed and indoor habitats develop humidity issues from the lack of air circulation, but they benefit greatly from being isolated from spores, seeds, and bacteria. Aquatic habitats, built to be open to the air, are always at risk of plant weeds and pests moving in. From mosquitoes laying eggs on the surface of the water to leaves that drift in and affect water quality and clarity, open enclosures need extra work to maintain the same water quality. This is especially true for small ponds and other in-ground water features located in otherwise dry enclosures. Being surrounded by soil makes these water features particularly prone to getting infested with aquatic weeds or algae that chokes out the feature. Runoff over the surface of the soil picks up nutrients to deposit them in the water, encouraging both desirable and undesirable plant growth. Lining the water features in exposed habitats reduces the rooting ability of weeds and makes it easier to remove algae manually when necessary.
Long-Term Maintenance
Zoo enclosures see a lot more maintenance on an annual and long-term basis than aquatic habitats installed in the wild. Due to the limited space and lack of interaction with a larger ecosystem, these enclosures aren’t as self-cleaning as real world habitats. This means that aquatic habitats, in particular, see a lot of scrubbing, power washing, and application of strong chemical cleaners to keep them sanitary and deal with any disease issues that occur. All of this maintenance work, over a decade or more, can put a lot of wear and tear on the materials used to construct the enclosure. Make sure to use durable and tough liner materials that won’t react to UV exposure or routine cleaning since they’ll need to last for years without replacement once permanently installed.
Aquatic enclosures in a zoo all differ since they have to meet the specific needs of the species hosted within them. Using a generic approach to the design of these kinds of unique and challenging habitats will only result in husbandry and care issues that cost the zoo unnecessary funding. The Zoological Association of America Enclosure Standards call for water features for many animal species, but they don’t necessarily explain how to build those features correctly. Start each enclosure design with a liner you can rely on, to hold the water back no matter what, with the help of BTL Liners.
