## How do I calculate what size basin I need for a pondless waterfall? | Decorative Ponds & Water Gardens Q & A

Q: How do I calculate what size basin I need for a pondless waterfall?

Robert – Waverly, TN

A:  With the help of a few friends, installing a pondless waterfall is an easy way to upgrade your land- or waterscape. If you are planning to design and build your own feature, here’s how to do the math to determine your basin size.

Step 1: Calculate total amount of water in your stream

Sound tricky? It’s not. To calculate the water that’s in motion in your stream, first measure your stream’s length, width and depth. Then plug those numbers into this equation: L x W x (0.25 x D of stream, generally 1 to 2 inches) x 7.48.

Here’s an example. If your stream is 25 feet long, 2 feet wide and 1 inch deep, the equation would look like this: 25 x 2 x (0.25 x 1) x 7.48 = 93.5 gallons.

Step 2: Calculate amount of water your basin needs to hold

As a general rule, you will need your basin to hold 2½ times the amount of water in your stream. To find out how much water your basin will need to hold, multiply the gallons of water in your stream by 2.5. In the above example, it would be 93.5 x 2.5 = 233.75 – so your basin would need to hold 233.75 gallons of water.

Step 3: Determine the size basin needed to hold the water

Here’s where things get a little tricky. You’ll likely use boulders, stones and other décor in your design. Well all that rockwork will take up space for water, and so you’ll need to go with a larger vessel.

Try this quick equation that will help you determine what size basin you’ll need with boulders: L x W x D x 2.2 = gallons of water the basin will need to hold. To give you an idea, a 5 foot by 10 foot basin that’s 3 feet deep and contains stone will hold 330 gallons of water.

A space- and cost-saving option is to use a basin matrix in place of some of the boulders. A basin matrix is a strong, 27-by-16-by-17½-inch hollow box that’s perforated with half-inch holes to allow water to collect and pass through. You can stack them together and landscape right over them. Each basin matrix holds 31.5 gallons, adding valuable water volume without increasing the size of the basin. Don’t forget to add a pump vault for easy access to your pump.

Go with a Kit

If you aren’t trying to customize a large waterfall, consider investing in a pond free waterfall kit, like PondBuilder™ Cascading Falls Pondless Kits. They contain all components you’ll need – from underlayment and liner to a waterfall box, pump, basin matrix and plumbing – with predetermined dimensions to help you create your water feature.

Pond Talk: What’s the largest size boulder you’ve installed in your water- or landscape?

## My pond is spring fed, so I don’t need an aerator, right? | Ponds & Lakes Q&A

Q: My pond is spring fed, so I don’t need an aerator, right?

Charles – Wadsworth, OH

A: Great question! First off, let’s tell the folks at home the differences between a catch basin pond and a spring-fed pond.

A catch basin pond is a reservoir filled with precipitation runoff—and pollution, in some cases—from the surrounding area. A spring-fed pond, however, is fed by a spring or ground water, which keeps the pond full. If you have cold areas of water in your pond, that could indicate that you have a spring-fed pond.

As the fresh water flows into the lake or pond from the underground aquifer, the water does move somewhat. But it doesn’t keep it agitated enough to naturally aerate it and maintain good water quality.

Preventing Thermocline

Whether you have a spring-fed or catch basin lake or pond, it’s critical to keep the water aerated. Why? Because doing so prevents thermocline, which is when the water forms layers, or stratifies, depending on the water temperature.

During the summer in a pond that’s not properly aerated, the water at the top is warmer and full of oxygen while the deeper water remains cooler and nutrient-rich. This phenomenon causes the fish to hang out at the pond’s surface. As the seasons change, however, the pond water does a “turnover,” which is where the warmer, oxygen-rich water sinks and the cooler, oxygen-depleted water to rise—leaving your fish gasping for breath.

Aerating Your Spring-Fed Pond

Obviously, you don’t want that to happen! So you should aerate your pond, even if it’s spring-fed. The action created by an aeration system, such as the Airmax® Pond Series™ Aeration System and the Airmax® Shallow Water Aeration System, effectively moves the water and causes the shallow and the deep water to mix. The Deep Water Aeration System is powerful enough to aerate ponds up to 3 acres and can be adapted to fit any shaped pond. The Shallow Water Aeration System is ideal for shallow lakes or ponds that require multiple aeration plates due to depth restrictions.

The result: oxygen is spread throughout the water column while dangerous gasses, like ammonia, are released at the water’s surface—and that means happy fish, good water quality and a healthy lake.

Pond Talk: Would you prefer to have a spring-fed or a catch-basin pond on your property?