Michelle Byrne Walsh is the Midwest Editor at State-by-State Gardening, a Master Gardener, freelance writer and a member of the Garden Writers Association.
 

 

 

How to Build a Dry Stream Bed
by Michelle Bryne Walsh - posted 10/30/12  

Want more structure to your garden? Have a spot where rain water always puddles? Looking for a hardscape project with a Japanese-inspired look? Ever hear of a dry stream bed? Dry stream beds are decorative stone features that can also carry rain water away from foundations and garden beds.

Have you ever wanted a water feature without the water (and the maintenance)? Ever hoped to add a bold, rocky, “Zen” aspect to the garden? Ever considered a dry stream bed? A dry stream bed can be purely decorative — something to lend a Japanese feel to the garden or a natural, stone yin to the garden’s yang — or it can be a rain water-directing device that stops erosion and helps control flooding.   

No matter if it is ornamental or functional; a dry stream bed can be an easy do-it-yourself project that adds drama to any garden or yard.     

Dry stream beds are usually used in one of two ways: within a Japanese garden to give the appearance of a stream, or as a practical solution to an area where water regularly runs through and it gets too wet to mow or tend, but 95 percent of the time it is dry.   

Nancy Gonsiorek, a University of Illinois Extension McHenry County Master Gardener who lives in Crystal Lake, Ill., installed a dry stream bed in her yard because of drainage issues. “None of our downspouts were trenched, and during heavy periods of rain we experienced some seepage in one part of our basement,” she says. “By digging a dry stream bed, I was able to take storm water away from the house and redirect it to a nearby river birch tree — a win-win situation. I gave the stream bed some gentle, natural curves and used river rocks and varying sizes of river cobble boulders, about 6 to 24 inches.” Near the birch and dry stream bed end Gonsiorek planted shade-tolerant natives such as goat’s beard, black cohosh, foam flower, maidenhair fern and lots of native sedges.   

In my garden, I installed a dry stream bed at the end of the property to channel water from the end of the sump pump hose, but mostly to serve as a focal point. The yard opens into a park-district-tended field, and I wanted to give the feeling of separation between my garden the field without blocking the view. 

Water, water everywhere?   


Streambeds should follow the contour of the yard, tumbling downhill and meandering among plantings.

Unless you are creating a Japanese-styled garden featuring a dry stream bed to suggest running water (and not to channel it), you are probably looking to improve water flow through your yard. So, first, think about the storm runoff and drainage. Where are the puddles after a rain? Do heavy rains wash away soil or mulch in sloped beds? Is there water seeping into your basement from the downspouts being too close to the house like in Gonsiorek’s yard?

Next think about the grade and slope of your garden. In general, you want the water to run away from the house, but there’s more to it than that. A pronounced slope will allow you to make the dry stream bed look like it belongs in your yard. These features look best when they follow a slope or appear to be flowing downhill.

It is also good overall design if the dry stream bed is sited where it will lead your “eye” from one existing design element to the next. For example, the dry stream bed could head toward a river birch and a wildflower garden like Gonsiorek’s, or link two or more perennial borders like mine, or define the edge of a path or a bed — or even become a path with raised stepping stones in the middle. 

Make it look natural    


Dry streambeds look best when they are “emerging” from planting beds or similar sites that would logically have a well-head or water source. You can see the pipe from the home’s sump pump here. During heavy rains, the pump sends stormwater through this streambed.

The streambeds should widen and narrow as they curve. Here a wooden foot bridge also acts as a focal point across a narrow point.

The most important thing to remember is to make it look natural and that means making it irregular and rambling. “It simply must meander,” says John Heaton, owner of Knupper Nursery and Landscape in Palatine, Ill. “Nothing in nature is straight. No straight lines.”

You also want the dry stream bed to have a variable width. It should become narrower and wider as it zigzags, Heaton suggests. “You don’t want a constant width with stones and boulders lined up evenly. You want slight width changes, changes in direction, and a change of rock shapes and sizes as the stream travels along.” For instance, natural streams widen on the bends. Boulders that are too large for the current to move remain in the middle of the stream. Similarly, smaller stones are washed to the center and to the end.     

To achieve this natural look, the deepest part of the dry steam bed, the center, should be filled with small river rocks that are smooth, such as river pebbles. Then add larger pebbles and medium-sized stones such as Mexican river pebbles, and then boulders that look like they belong in the area. And stick to a uniform color palette. Using red, black, blue, gray and brown boulders and pebbles all jumbled together looks unnatural, Heaton says.

If your garden is small and the dry stream bed is also small, choose smaller river rocks and boulders. If you are making a large-scale dry stream bed in a large yard, the rocks should also be proportionately bigger. Plus, if a large quantity of water will flow through the stream bed during a storm, be sure your gravel and pebbles are heavy enough so they don’t get washed away.     

Also, avoid placing rocks in any pattern whatsoever. Place small- and medium-sized stones along the center of the channel and larger rocks or boulders both along the banks, but don’t line them up evenly. And place some boulders in the middle of the stream to look as if they were too heavy for the current to move. Then mimic nature by placing some rocks on top of each other and partially burying others.   


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Have the streambed end in a logical spot, such as behind a group of shrubs at the bottom of a small hill, and try to make it look like stones spilled down the waterway and “stuck” where they are. Also try to incorporate different sizes of boulders, river pebbles and gravel.

Where to start? Where to end?

When starting the dry stream bed, make the “headwaters” narrower, then have the course change and become wider. Then vary the direction and width repeatedly as the stream progresses. Remember that natural creek beds are usually wider than they are deep. Follow the lay of the land and the direction of the slope.

“The width should change by thirds,” Heaton explains. “For instance, if it starts with a 1-foot-wide bed, then it should widen to 1.5 feet at one point, perhaps turn, and become 3 feet at a further point. This transition should occur every 10 feet or so.” Widen and narrow it gradually.

Have the stream bed end at a logical point, too. “Extend it through a hedge, or under a fence—again, try to make it look like nature put it there,” Heaton says.

You can put a rain garden at the end of a dry stream bed, too.

After your dry stream bed is installed, it will be a fairly low maintenance feature. Weeds might grow up between the rocks, and Heaton recommends spraying these weeds with a non-selective herbicide like glyphosate rather than hand pulling. Pulling weeds that are rooted into the landscape fabric might disturb or tear the fabric, which can lead to more weeds. “It is critical that the dry stream bed look like it fits into the landscape,” Heaton emphasizes.

“It needs to flow, like a small stream would, and it needs to be suited for your yard’s special situations. And when installing it yourself, give yourself the proper amount of space and enough time necessary to do it correctly. It’s really a great do-it-yourself project.”       


Plants like Sedum ‘Angelina’ make good companions with rocky features like the streambed.

Installing a Dry Stream Bed 

  1. Lay out the course using landscape paint, small flags, or a garden hose. Follow the slope of your yard (downhill) and create a meandering path. Be sure it narrows and widens and starts and ends in logical places.
  2. Clear the area of grass and weeds. Use a non-selective herbicide like glyphosate (and wait the recommended amount of days) or use a sod cutter or a spade to remove the sod.
  3. Using a shovel, excavate the stream to a depth of about 6 to 9 inches up to about 1 foot. Place some of the excavated soil along the sides to create small banks (especially at the outside of the curves). The sides should descend gradually toward the center.
  4. Set landscape fabric in the ditch. Fabric should extend about 6 inches on each side, where boulders and stones will be placed on top. Pleat the fabric to accommodate turns. Secure with landscape fabric staples or fasteners.
  5. Pour in a 2- to 3-inch layer of washed gravel (3/4 or 1 inch in size). Pour sharp sand or torpedo sand on top to sift through gravel for a natural look.
  6. Place the boulders. Boulders should vary in size. Avoid organizing the rocks in any pattern. Place boulders on the banks and a few of the larger ones in the center of the stream. Use large boulders at the bends in the stream and to disguise the headwaters.
  7. Place river pebbles and rocks on top of the gravel and sand and between the boulders. Use various sizes. Some types to consider include Mexican river pebbles, river pebbles, pond pebbles and smaller sand pebbles. Spread smaller river rocks at the lowest end to create the appearance of naturally deposited sediment.
  8. Create plantings. As in nature, be sure plantings aren’t lined up along the stream bed. Include trees, shrubs or perennials, as desired. Plant some through openings in the landscape fabric.
  9. Keep weeds out by hand-pulling very small weeds or using a non-selective herbicide like glyphosate to kill deeply rooted weeds. Hand pulling large weeds could disturb or tear the landscape fabric beneath the stones.

Photos courtesy of Michelle Byrne Walsh.

 

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