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LANDSCAPE DESIGN AND CONSTRUCTION www.landscapeirrigation.com Landscape and Irrigation July/August 2015 25 a stream is different," said Helfrich. Depending on the size of the yard, a stream may be five feet long and empty into a pondless water feature. Or it may leisurely wind around the property for several hundred feet. The key is understanding how the natural typography of the property affects the flow of water and subse- quently the ambiance created. Before designing and installing a stream on your client's prop- erty, find inspiration in nature. "When I design streams, I think about water in nature and what it looks like," he said. For example, if you've ever flown in a plane and have looked out the window, you can see streams carelessly zigzagging across flat farmlands. "On the other hand, water cascading down a hillside will follow the path of least resistance, so you won't see a lot of twists and turns on a steep slope," he explained. Instead, the water will fall quickly at different angles forming a "staircase". Understanding the effect moving water has on the soil on the edges of a stream bed is equally important. "One idea I use to help people create natural-looking streams is remind them that water erodes the earth and leaves behind the stones it could not move," he said, "a landscape stream should look like it has carved out the earth, not built it up." Once you've studied a natural stream and are confident you can replicate one, it's time to get to work. Use the existing terrain to sculpt a stream that looks as if na- ture placed it there. To achieve a genuine, natural look, on a flat piece of property, incorporate multiple twists and turns rather than trying to build up banks for waterfalls. Without natural elevation change, significant amounts of soil are needed to build up areas for elevation changes to create a cas- cading waterfall effect. "When adding that much soil, you run the risk of creating a volcanic experience, making it look artificial," said Helfrich. While a flat yard is not best suited for aggressive, cascading waterfalls, it can be equally as interesting. "A deep stream can work well in a flat yard. If it's deep enough, fish can even be added to it," he said. For streams that will be stocked with fish, Helfrich suggests a 45-mil. fish-safe liner. Small yards can be equally challenging. "It's harder to incorporate a 20-foot stream into a small backyard. There just isn't room to cre- ate a lot of mystery," he said. "It's not impossible, just more difficult." Properties with a slope and/or multiple grade changes lend themselves to cascading waterfalls and greater creative design. "Create fast-moving water with shallow portions and slow-moving water through deeper sections," he said. Varying the speed also changes the sound effects produced. "It's easier to carve natural- looking stream beds into the side of a slope than it is on less var- ied terrain," he said. For a finished look on a stream of any size, use a carefully selected mix of large boulders, medium rocks and small pebbles to construct the stream bed. "I recommend a 1:2:1 ratio of small, medium and large boulders," he said, "that avoids a necklace look that is unnatural." THE NITTY GRITTY Streams allow for imagination and creativity, but there are sev- eral technical elements that are critical for achieving a functional, natural-looking stream. "The most common mistake that is made is designing a top- heavy system," Helfrich said. A top-heavy system places the larg- est volume of water at the headwater or beginning of the stream, rather than at the end. For example, a 30-foot stream that flows out of a 20-foot x 20-foot pool and empties into a 6-foot x 8-foot pond will overflow the lower reservoir it empties into. Even when the circulation pump is off, gravity will carry the excess water downstream. It's also important to remember that the pump used to re- circulate the water and the associated plumbing must be sized correctly. "Adding a 10-foot stream to a pond or waterfall is prob- ably not a big deal," he said. "But as the distance of the stream in- creases, the size of the pump and plumbing will have to increase too." Distance and grade change will determine the appropriate pump size. The pump and plumbing can be engineered for any size stream, but it can become costly. "Budget can become a limit- ing factor," he said. As the stream increases in size and the grade change increases, the evaporation rate also varies. Evaporation rates also increase as more waterfalls are added. "You want to make sure the final reservoir is sized correctly so that the client doesn't have to refill it every day," he said. Adding an autofill valve to the system easily regulates the water level. ADDING ENHANCEMENTS Once the stream is conceptualized and installed, other elements can be added to enhance the overall design. The banks of the stream become ideal planting spots for native plants that can be used to add texture and intrigue. "Using plants of varying heights allows the stream to disappear and reappear, adding intrigue," he said. Not only will they add as aesthetic appeal, but native plants will also provide habitat for wildlife. Water features naturally lend themselves to the inclusion of a bridge. "There is not a person in the world who can resist crossing a bridge," he noted, "but everyone thinks of a standard, wooden arch bridge." Consider adding an element of surprise and use a stone slab instead. Position the stone so that it ap- pears as if the water eroded the earth beneath the stone to flow under it. "If you're going to incorporate a bridge, don't disappoint by having a bridge that leads nowhere," Helfrich cautions. Reward people who cross the bridge with something new to discover. "It could be a bench under a shaded tree, a vegetable or flower gar- den," he added. Regardless of whether your client's property is better suited for a trickling brook or a briskly flowing creek, a stream adds movement and sound to any garden, and is a viable option for any landscape. "Remember, a stream is a custom creation, and your creativity is not really limited by the space available, but by the typography of the property," Helfrich concluded. Katie Navarra is a landscape industry professional based in New York. She is also an accomplished author and freelance correspon- dent with more than 200 articles to her credit. She can be reached via e-mail at katienavarra@yahoo.com. LI