Barb and Gary Rudolf are experienced water gardeners from Petersburg, Virginia.

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Seamless Stream
by Barb and Gary Rudolf    


The Oriental-inspired bridge spans the midsection of the stream and leads to several gravel-lined garden paths.

Water features are a hot topic in gardening. Even mainstream publications are touting them. However, most of the publicity blitz focuses on ponds, fountains and water gardens in containers. If you are interested in exploring water gardening, have you considered a cascading stream?

A man-made stream is a feature well suited to any site that is not perfectly flat. For landscapes characterized by ordinarily problematic elements, such as slopes and changes in elevation, a cascading stream can be an excellent addition. Include a small pond to collect the falling water and you have landscape interest in abundance.

A stream is ideal for both introducing some new and interesting plants and arranging them creatively. Some aquatic plants that are routinely recommended for a pond will not work in the stream environment, but there are many that thrive in rapidly moving water.

A basic assumption is that the stream should have a natural appearance, one that mimics what is found in a natural environment. This offers considerable challenges. Undoubtedly, establishing and maintaining a pond water garden is easier than a stream in a number of ways. However, a cascading stream definitely has its seductive charms.

Ours is so inviting and beautiful that it readily draws us and visitors away from the playful pond fish and large calming body of water to the stream’s cascades, the sparkle of spray playing over rocks, and the music of running water. An array of plantings accentuates the water flowing around, over and underneath various rocks.

Additionally, the relatively narrow width of the stream facilitates the introduction of a bridge or bridges spanning the water. Crossing a bridge affords many vantage points for observation and provides a link between different garden areas bordering the stream.

Does this description sound alluring? The stream highlighted in this article was installed in the late summer of 2001. We’ve been adding plants ever since, but primarily in the first few years. Each year as the streamscape is enhanced, it matures and becomes more beautiful and closer to our vision.

 

Construction

Stream Water Flow Mechanics,
A Balancing Act

• Understand the cycle – A cascading, downhill stream actually begins at the bottom of the watercourse:

1. The pump draws in water from the collection pond and powers it uphill through underground plumbing paralleling the stream.

 2. The water is expelled as a waterfall at the stream’s apex.

 3. The stream water then descends via gravity, speeding up over the cascades and slowing in each level area before the next fall.

 4. The final cascade dumps water into the collection pond where the pump is located.

• Maintain the equilibrium – If the volume of water becomes significantly unbalanced at any point in the cycle, the stream will eventually “run dry.” Too little water in the collection pond will cause the pump’s protection mechanism to cut off. The water remaining in the stream will descend into the collection pond, possibly causing it to overflow its boundaries. Similar problems occur when the electrical service to the pump is interrupted, such as from a power outage.

To restore the flow requires slowly adding water with a garden hose in the upper stream and restarting the pump when the collection pond attains its normal water level. It will take some experimentation to determine the best intervention techniques to keep your stream running smoothly. Remember that during dry spells in the summer, some water will be lost from evaporation, and spray from the cascades also gradually reduces water volume. A preventive measure is to periodically add a small amount of water to the stream even when the cycle is operating as described above.

We had earlier unearthed a broken concrete walk that followed a slope on one side of our backyard. This original landscape feature (probably dating to the late 1920s to early 1930s) provided an inspiration and template for adding a cascading stream. The concrete was removed and its path excavated further. Then carpet padding and a butyl liner were placed and anchored with fieldstone. A number of smooth river rocks bordering the old path were also used in the stream.

The stream originates from a man-made waterfall consisting of two PVC pipes placed back to back with a larger waterfall that spills into our pond. While plumbing and electricity for the stream are totally separate from the pond’s mechanics, it is intended to appear that the moving water for both features originates from a single source. The stream terminates in a small pond. Adjacent to this pond are a skimmer, filter and pump. The latter continuously pipes water from the collection pond uphill to the dual stream waterfalls.

To make all of this work requires calculation relative to the length and degree of descent of the stream, the water volume, the desired flow rate (rapid, meandering or somewhere in between), and the appropriate pump capacity. At the time the streambed is excavated, another trench or trenches must be dug to lay pipes and install wiring for the pump – all designed for outdoor, subterranean use of course. You will also need to dig out an area to situate and hopefully conceal the skimmer box, filter material and pump.

During trial runs of the stream when construction is completed, you should carefully observe the course of the water and ensure that the liner is secure. You don’t want water to escape the rock-lined streambed. At the same time, the stream must be constructed so that runoff from the garden drains away from, not into, the water feature. Adjust rocks in and around the stream to modify direction and volume of flow, as well as for aesthetic considerations.

If in doubt about any aspect of the soundness of the stream’s construction and installation of the mechanical components, now is the best time to make the necessary changes. Once you have started to plant in and around the stream, fixing any problems you encounter becomes more difficult.

 

Landscaping


The collection pond at the stream’s terminus is glimpsed at the upper left behind the Japanese maple.

Your new stream is finished, and everything is working perfectly. Now take a critical look at your accomplishment. What you are likely to see is two seemingly massive rock borders defining an interesting watercourse, but why does the whole thing look so darn artificial? The answer is it lacks natural-appearing planting. Study streams in nature and observe how plants grow in and around them, spilling over the banks and softening the predominant “rock pile” effect.

The challenge facing you is to seize every opportunity to place appropriate plants in, bordering and around the stream. Your success in landscaping will determine the ultimate appearance of the stream and its seamless integration into the surrounding gardens. Bear in mind that plants that are located in, or reach into, the stream help capture debris and maintain the sparkling clarity of your cascades – though we’re not claiming that human assistance is not required to occasionally remove leaves and so forth from crevices between rocks and in the pond where the stream terminates!

           

Two strategies anchored our efforts to naturalize the stream through its plantings.           


Deeply shaded woods heighten the serene feeling a cascading stream can add to the landscape.

1. Use the rocks in and bordering the stream to create numerous plant “pockets.” Purchase small potted ferns, groundcovers and plants that don’t mind “wet feet.” At the outer edges within the stream, arrange three or four rocks securely that can hold a small amount of soil. Fill gaps with pea gravel and top with a thin layer of your preferred planting soil. Remove the plant from the pot, spread roots as required, and place in the pocket you’ve built. Fill in around the plant with soil, firm and top with pea gravel and larger stones if desired. Water thoroughly.

If you’ve followed these steps, little or no soil should escape into the stream, but the plant’s roots will be able to obtain adequate moisture from stream water and rain. You can also plant aquatic plants that tolerate moving water by securing their roots in crevices between rocks and anchoring them with gravel or small rocks.

           

2. Add soil surrounding the rock borders of the stream to level its edges with the adjacent landscape. This action is critical to achieving a natural appearance. As noted above, care must be taken to ensure that building up the adjacent ground does not allow a significant volume of runoff to drain into the stream. The soil you’ve added will settle. You may want to wait several weeks before planting, and, if necessary, adjust the grading to fill up close to the height of the top of the rock borders.

Your plant choices for the areas bordering the stream are very important. Rapidly spreading groundcovers, perennials, shrubs and trees build root systems that anchor the soil and control overflow problems and erosion.

Consider plant shape and habit, size and cultural needs. Use plants that have similar soil type and water requirements. Seek variety in leaf sizes, shapes, and colors. By all means, create interest by mixing spreading, upright and weeping plant forms.

 

Maintenance and Troubleshooting


The cascading stream bisects lushly planted beds. Beyond is a descending path backed by more shade-loving garden beds.

Your stream will probably not remain trouble-free without some assistance from you. Routine maintenance tasks include checking the water level in the collection pond, clearing vegetative debris from the water and rocks, cleaning out the skimmer and filter, and monitoring the surrounding rocks and terrain to detect drainage problems and settling of the boundaries. Regular attention to these potential problem areas will enable you to avoid many situations that disrupt the balance of your waterfall-stream-pond circuit.

Mechanical breakdowns that occur out of sight, sometimes underground in the plumbing and electrical systems that power the stream, can be more difficult to locate and correct. It is always advisable to check all of the obvious causes of water loss or leakage first before excavating your pipes or wiring.

If you are losing inordinate amounts of water, try to successively isolate the flow into each “cell” (the level parts of the stream between cascades) to examine for holes or tears in the liner.

Finding the liner to be sound is certainly a relief, but now you will have to do some digging – literally – to identify weak points in the electrical and plumbing systems. It’s best to start in the areas where you know connections between pipes exist. These are likely sites for failure.

When you ultimately locate the source of the problem and correct it, a recommended insurance measure is to rebuild the damaged component or buy a spare in addition to the replacement. This prepares you to immediately address the same problem in the future should it recur.

Don’t let this advice on problem solving deter you from considering the addition of a stream to your garden. The enjoyment of this feature will far outweigh the work and vigilance required to keep it in top shape.

 

Some Good Plants For Locating In A Stream

• Sweet flag (Acorus) – all varieties

• Water celery or water parsley (Oenanthe)*

• Horsetail (Equisetum) – all varieties*

• Ferns – all varieties that prefer damp soil, especially deciduous ferns

• Ribbon grass (Phalaris)*

• Reeds (Juncus) – all varieties, especially curly reeds

• Creeping Jenny (Lysimachia)*

• Chameleon plant (Houttunyia)*

 

* Note: These plants can become invasive once established. Only you can decide when they become too much of a good thing.

 

(From State-by-State Gardening September 2004. Photos by Barb and Gary Rudolf)

 

Posted: 06/29/11   RSS | Print

 

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COMMENTS

Elaine Knight (Troy, AL 36081) - 07/14/2011

I really like the look of a water stream since my yard is anything but flat…..........enjoyed the article….......

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