Ornamental and Retention Ponds
Bridging the Gap Between
Thousands upon thousands of ponds are being built across the country. Some ponds are strictly ornamental, while others are put to work, having a utilitarian purpose other than beauty. I’ve been working at Aquascape Designs, Inc., the country’s largest water garden builder, for over 10 years now and have built every kind of pond, from small, backyard paradises to large, commercial retention ponds. I’m also a firm believer in the fact that retention ponds don’t have to look like a big, swampy hole in the ground. In fact, they can be both functional and beautiful. This article is designed to break down the barriers of ornamental and utilitarian ponds.
First, we need to understand the differences between these various types of ponds.
Let’s Consider a Hybrid
Aeration systems that are borrowed from aquaculture will revitalize the anaerobic depths of stagnant ponds. Waterfalls and large bog filters incorporated into the design, will beautify and create a park-like setting. Instead of creating ponds out of sheer necessity, let’s create them as an aesthetic asset of the property’s design, which includes storm water management and irrigation.
This sounds great, but where do we start? If you’re lucky enough to be involved in the planning stages, the pond can be more carefully thought out so that all criteria are met. Unfortunately, there is a large number of ponds in existence that need help.
I usually start with the structural work first, creating contours and stonework. This sets the stage for introducing planting beds that are both aquatic and terrestrial. The perimeter can be altered to create a more interesting, naturalistic shape by creative rock placement and some re-grading of the pond’s edges.
The new edges are designed to recreate a natural pond’s marginal zone. It will be necessary to drain the pond down to the safety ledge, which is approximately 3’. Using boulders to build retaining walls, line the back of the walls with a geotextile and backfill with soil or gravel. Simply slant the planting bed from the shoreline to a depth of 12” at the top of the boulder wall.
The edges can then be planted with a variety of marginal aquatic plants. The plants are chosen for their ability to remove nutrients from the water, their interesting foliage, and their colorful flowers. We can create a seamless transition from aquatic to terrestrial perennial beds. Other edges can be rocky with boulder outcroppings, or beaches can be created by using smooth river rock and gravel. On large ponds, I prefer a combination of edge treatments.
Water lily pockets are placed in large groupings to create a more dramatic display. If possible, lower the pond’s water level to approximately 3’ to expose the pond’s bottom. Create a lily pocket by digging into the bottom sediment (in a liner pond place a ring of boulders on the liner and add a layer of landscape fabric), fill with soil, plant the lilies and cover the soil with gravel.
Finishing It Off
There are several different types of diffusers on the market; the basic concept is to create small bubbles of air. As the bubbles rise to the surface, they take surrounding water with them. The water on the pond’s bottom is brought to the surface and exposed to the atmosphere, where it can absorb oxygen.
The continuous cycling of an aerator will efficiently oxygenate the entire pond. The increased oxygen levels will speed up the aerobic digestion of organic wastes and create a better habitat for all forms of aquatic life.
In the process, we’ve made some dramatic changes in the structural rebuilding phase. We’ve changed the pond’s contours, installed aquatic plants, and aerated the water, giving the pond a new look, as well as a foundation to start its reestablishment as a healthy aquatic feature. Now that we’ve created the structure, it’s time to give it some heart, soul, and character.
Pumps and Pipes
I’m a proponent of multiple pumps. They’re readily available, easy to install, and eliminate the problem of a total shut-down during maintenance. If one pump needs to be serviced, the others will continue working, keeping the filters alive, and your clients happy. Think of them like kidneys and lungs; ideally you have two of them, but you can survive on one. In natural ponds, skimmers do not work because of fluctuating water levels.
A wet well is the preferred methodit’s more professional, works better, hides everything, and is easy to service. I use a Snorkel Vault set into the shoreline of the pond to house the pump. This provides protection and easy access to the pump for service. A Centipede Module extends off the bottom of the vault as an intake. The open spots in the intake allow for sufficient water flow, while helping to prefilter out larger debris that could potentially clog the pump. Small boulders are stacked around the intake in order to further prefilter the water. The location of the intake at the bottom allows for a few feet of water fluctuation in the pond without starving the pump of water (see diagram 5).
On large liner ponds, wet wells can be used in conjunction with skimmers. The skimmers are used to keep the surface clear and the wet wells are utilized for their large pumping capacities and low maintenance. The structure is placed on top of the liner and plumbed accordingly.
Streams and Waterfalls
A waterfall and stream can be created at the outflow of a constructed wetland filter. The water flows through this patented natural filter, stripping it of sediment and nutrients as it passes through several layers of aggregate and aquatic plants. The vault has an easy access lid that allows the sediment loads to be pumped out on an as needed basis. This feature significantly reduces the need for costly and invasive dredging or excavation of sediment loads in the retention pond. The constructed wetland filter is modular and can be constructed in a variety of shapes and sizes. Like ornamental ponds, you can set the filter away from the pond and the water can twist, turn and tumble its way down a stream before entering the pond, or you can simply construct it into the margin of the pond and tap into the incredible filtration capabilities of the wetland filter.
Always take the viewing areas into consideration when designing streams and waterfalls. Will they be viewed from 20 feet or 200 feet?
On larger ponds and streams, I’ll typically use larger boulders. When working with large rocks safety is my number one priority.
When laying out my streambed, I’ll pick out the areas where large rocks will be placed. Make sure you leave enough room in the stream to accommodate the stones. You don’t want to choke the stream down, so over-dig to compensate. After the liner is installed, position the boulders and then backfill with soil. You can also fill the void between the boulders and liner with smaller stones and gravel. Black foam should be used to divert the water as necessary. The finishing touches will remain the same.
As you can see, we can transform ordinary retention areas into extraordinary water features. By following the same concepts used for smaller water features and incorporating a few specialized techniques, any pond can become a showplace.
For more information contact Ed Beaulieu, V. P. Construction, Aquascape Designs, Inc., 1200 Nagel Blvd., Batavia, IL 60510, (866)877-6637, (630)326-1800, e-mail: firstname.lastname@example.org, website: www.aquascapedesigns.com.
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