The winery industry uses billions of gallons of water per year between growing thirsty grape vines and washing out large fermentation tanks. With 7.5 billion gallons of wine produced in 2018 and anywhere from 2 to over 30 gallons of water used per gallon of finished beverage, it’s clear that every gallon is precious. Allowing for waste, or loss of valuable irrigation water in particular, tends to increase costs and make it harder for wineries and vineyards to meet local and state regulations on water use. Storage ponds are one of the best steps to providing for a steady irrigation supply, but they’re only a good choice when well-designed. Find out what you need to know about lining your winery irrigation pond to prevent water loss and other issues.
Controlling Seepage and Leaks
Only impermeable barriers such as a flexible pond liner can actually keep water in and reliably control seepage and leaks. Other products commonly reused or used as pond liners, clay, bentonite, and roofing membranes aren’t actually impermeable. Even concrete allows water to slowly escape unless it’s coated with another sealant or paired with a flexible liner. Impermeability describes a material’s ability to keep liquid from moving through it. Few materials are absolutely impermeable, but reinforced polyethylene (RPE) is as close to it as a flexible liner can get. Liners are primarily designed to control seepage and leaks, along with offering soil stabilization and control of ground water infiltration.
Pond depth plays an important role in preserving both water quantity and quality. Shallow ponds stay warmer than deeper ones, allowing algae to flourish that rapidly clogs irrigation emitters and lines. Algae also changes the pH and nutrient levels of the water, which may affect the health of the vines in the long run. Without a liner, seepage will lower the water level and encourage evaporation to further exacerbate the problem. Using a liner also allows for easy dredging when it’s necessary so that the pond continues to hold the same amount of water. This is especially important for wastewater processing and storage ponds since they fill up quickly with organic material.
Keeping Steady Water Quality
Irrigation ponds don’t need the steady water quality and tight pH parameters you’d need for a fishpond or natural swimming pool. Yet, they still need a basic level of water quality to avoid unnecessary damage to the irrigation equipment itself. Micro-sprayers and drip emitters are particularly prone to clogging due to algae, sediment, or mineral build-up. They’re also highly efficient, so they’re worth using despite the risk of tedious de-clogging routines. Lining the pond keeps water quality steady in multiple ways:
- Prevents ground water from rising up and adding salinity or hardness to the supply
- Controls sediment and muddiness by separating water from the mud below
- Eliminates edge erosion when installed correctly
- Lasts through multiple cleaning and sanitizing processes without breaking down
- Lack of chemical leaching as long as the right liner material is selected.
Which Liners Work Best for Irrigation Ponds?
Irrigation ponds don’t need fish safe liners, but plant safe liners are not a bad idea. Some of the same chemicals that can leach from certain liners and affect water plant growth could still have an effect on soil health. For most installations, durability is the primary concern since few winery owners’ budget for extensive pond renovations every few years. Irrigation water rarely has any specific chemical reaction risks when freshly diverted from a river or pumped from a well, but it’s a different story when you’re reusing wastewater for irrigation. Here’s what kind of liner to look for when shopping around.
Polyethylene, Polypropylene, or Polyvinyl Chloride?
As the prefix on all three of these names suggests, most pond liners are made from flexible materials known as polymers. While they may share similar names, these materials vary greatly in their suitability for lining a winery irrigation pond. Some will work for other agricultural applications, while others are just not a good choice for most outdoor pond applications. You’ll find polyethylene, also abbreviated as PE, is the best choice for irrigation ponds in general of these three. Polypropylene, or PP, is the second-best choice and is commonly used as a thicker underlayment to protect all kinds of liners. Finally, polyvinyl chloride, better known as PVC, is the worst choice and should be avoided unless it’s the only option.
Polyethylene wins the polymer competition because most of its variations are highly chemical resistant while providing good durability and UV resistance. Naturally, each type of polyethylene varies in its specific mixture of benefits and disadvantages. High density polyethylene (HDPE) is stiffer and stronger, but it can suffer from damage when installed in cold climates with loose soils that shift. Low density polyethylene (LDPE) is more flexible, yet not as durable. The best polyethylene liner combines both LDPE and HDPE in one reinforced package to create a pond liner that can handle almost any irrigation challenge.
The Question of Rubber
Aside from the thinner flexible polymer liners, you’ll also find thick sheets of rubber sold for this purpose as well. Most of these rubber liners are made from Ethylene Propylene Diene Monomer, better known as EPDM. EPDM was originally designed as a roofing membrane to protect low-slope roofs from standing water that would otherwise damage the structure. Many EPDM products still sold as pond liners are in fact designed solely with roofing use in mind. EPDM liners are thick, heavy, difficult to move and install, and prone to leach out chemicals unless they’re explicitly plant safe. EPDM is generally not a good choice for irrigation ponds unless it’s the only flexible liner available in the area. It does come in fish and plant safe formulas, but it’s usually less resistant to UV damage than polyethylene liners in particular.
Reinforced vs Non-Reinforced Liners
Aside from choosing the rubber or polymer used to manufacture the liner, you’ll need to choose between non-reinforced and reinforced products. Reinforced liners feature an extra layer of reinforcement material to add tear and rip resistance. No matter what kind of pond you’re planning, including a winery irrigation pond, a reinforced liner is a better choice. It’s much easier to prevent damage during installation in particular. When dragging a thin and flexible liner material over bare soil, it’s all too easy to form a rip when a forgotten root or rock catches the sheet. Reinforced liners also resist damage after filling. Wrinkles left in the liner fold sharply when the weight of the water presses down on it. Reinforced liners are less likely to crack open and leak at these points than non-reinforced materials.
Why You Don’t Want Re-purposed or Roofing Materials
Many winery owners assume that reusing or re-purposing some other material or liner is an eco-friendly way to reduce installation costs for a new irrigation pond. However, using something that is not specifically designed for pond liner use will only result in lower water quality, contamination issues, and leaks that seem impossible to stop. Avoid billboard liners, various types of tarps, and other polymer sheets not intended for pond use. Even if these re-purposed products are being marketed as safe for irrigation, a new, purpose-built liner is a better choice. Re-lining, to deal with a badly chosen material, will cost thousands of dollars and interrupt your usual irrigation routine.
Tips for Installing Flexible Liners
Even the best flexible pond liners require careful handling and some extra attention during installation to last for years under the weight of the water. Spending a few extra hours, or even an extra day, on the installation process can pay off with many extra years of problem-free service.
- Plan any penetrations and piping or electrical lines that must run under the liner well before installation. Penetrations should be cut and sealed with matching sealants and boots/covers to ensure as much protection against leaks as possible.
- Install an underlayment to protect the liner from sharp materials that could rip or tear it. The smooth cushion of felt-like underlayment also speeds up installation by helping the material slide and spread without tearing or stretching.
- Use smooth weights like rounded river rock, jugs of water, or hardened bags of concrete to hold down the liner material while working on it. This prevents wind from interrupting your work while you’re sealing seams and trimming overlapping material.
- Start adding the rocks or other materials to anchor the liner to the edge as you get the material stretched out. You don’t need all of the intended rocks or anchors, just a few scattered around the entire perimeter to maintain some tension as the liner is spread out. This prevents the material from stretching or moving as you adjust it.
With or Without Concrete?
Some winery irrigation pond owners only discover the benefits of flexible polymer liners after finding out their existing concrete structure is leaking. Concrete is commonly mistaken for an impermeable and seepage-proof liner material for a pond. However, it’s more of a structural reinforcement material than a true liner. Concrete has tiny pores on its surface that cause it to act as a slow sponge, transferring water from inside the pond to the soil outside of it. A concrete lined irrigation pond will still allow too much seepage of the valuable water that’s needed in the vineyard.
Ballast and Cover Materials for Liners
While it’s relatively easy to get a flexible liner material to conform to the surface of the soil while the pond is empty, many new irrigation pond owners are dismayed to see their liners rising up like whales at the surface. Floating liners are caused by a wide range of issues like:
- Gas build up from plant material left behind that is decomposing or from the soil itself
- Water rising from a high, water table or from running between the liner and the soil during a storm
- Tree roots and animals burrowing under the liner and causing water or air to accumulate in pockets.
Spreading a layer of gravel, sand, rocks, or soil over the liner is one of the most reliable ways to keep it from rising regardless of the cause. This is known as ballast. If you choose a liner that needs extra protection from UV rays, the same material also serves as a cover to keep light away.
Don’t let the sheer variety of pond liners available on the market today overwhelm you. You don’t need to become an expert in pond design just to improve your winery or vineyard with a new irrigation pond. Here at BTL Liners we’re happy to help advise you in proper liner selection as you design and build a new pond. Tap into our expertise to get started on your winery irrigation project as soon as possible.