- First plan the course that the dry creek bed will take down the slope. Mark the 2 edges of that course with landscaper's paint. A meandering course looks more natural than a straight course. How high up the slope should you start? In some cases, there's little choice. For instance, if a landscape drainage pipe that's already in place is dumping all that excess water onto your property, your decision is clear-cut: begin the project by grading the land right under that pipe....
- But in cases where you have more leeway (especially for features that will be purely decorative), attempt to disguise the "headwaters" of the dry creek bed by making it bend out from behind a large boulder or some plant material. When the source of a stream is mysterious, viewers have to use their imagination. And what we construct with our hands is rarely as pleasing as what we construct with our minds.
- We've talked about how high up the slope to start. But what about where to finish down below? Some homeowners redirect excess water toward the street. But it's best to contemplate a worst-case scenario when dealing with public property, because that means dealing with the government -- which can be a real stickler when it comes to issues like redirecting excess water. So check with your local public works department first. If their response is positive, get something in writing that says so.
- What if you're not allowed to redirect the water to the street? Unless you already have a landscape drainage system in place (allowing you to route the runoff into that system), you have 2 main options. You could channel the water to a location on your land (but make sure it's your land, not a neighbor's!) where it's less troublesome and where, if the soil is sandy enough, it can percolate harmlessly down into the ground. A second option is to build a pond and funnel the water into it.
- So much for the course. What about its depth and width? These dimensions don't have to conform to any rule exactly. Look at dry creek beds in nature: they're obviously not all of the same depth and width. But there's a general rule you can follow: dry creek beds tend to be wider than they are deep, which is good news for you -- less digging! A 2:1 ratio is about right, meaning you could make your feature 3 feet wide x 1.5 feet deep, for example.
- With the planning done, now it's time for the first real work in the project: the digging. It's easy to build dry creek beds for landscape drainage, provided that the soil you'll be excavating isn't strewn with roots and rocks. Those with difficult soil to excavate can take solace in the fact that the excavation will be the toughest part of the project!
- Take the soil that you're excavating and mound it up along the sides of your dry creek bed, as you go. This will reduce the amount of digging that you have to do, since you'll be lowering the base and raising the sides in one motion. Tamp down this excavated soil with a tamping tool.
- After the trench for the dry creek bed has been excavated, lay down landscape fabric along its whole length. You want the fabric to cover the mounds of earth on both sides, as well as the trench. Hold the fabric in place using fabric pins or garden staples. Now for the part of the project that will be visible to viewer's: the rock....
For projects intended to improve landscape drainage on very steep hills, some folks mortar the rocks into place to form a solid channel that will carry water away. Unless you find this measure unavoidable, however, it may be best to avoid it. Mortared structures in contact with the ground are susceptible to frost heaves in cold climates (to guard against which you can dig your trench deeper and apply a few inches of crushed stone before laying down your landscape fabric). The good news is that the use of mortar is usually unnecessary for dry creek beds located on all but the most severe slopes. If you're afraid of having your stone wash away, use lots of large stone to anchor the project.
If you do use mortar, apply it only to short sections of the fabric at a time, since mortar dries quickly. Use at least 2 inches of mortar. Lay the rocks in the mortar, then repeat the process with the next short section. It's easier to work from the top of the slope, down.
- You can use rock of various shapes and sizes, but many homeowners prefer to select more round rocks ("river rocks") than flat ones. Round rocks conjure up an image of the water that has been gushing over them, knocking them about and causing them to become round over time.
- Place small river rocks in the center of the trench; the water will flow over these.
- Place your larger rocks on the sides of your feature, where they'll help channel the water and where they'll have the most visual impact. Save any boulders for the biggest bends in your stream's course and to disguise the "headwaters" of the dry creek bed (as discussed in Step 2 above).
- After you build dry creek beds, you can dress them up a bit. Plants will soften the edges, for instance. If you're more ambitious, you can install a landscape bridge over the feature and plant tall ornamental grasses to serve as "bookends" at both entrances to the landscape bridge. Adorn the landscape bridge with hanging container gardens to create a knockout focal point for your yard.
What You Need
- Landscaper's paint
- Landscape fabric
- Fabric pins or garden staples
- River rocks and boulders
- Mortar and wheelbarrow for mixing the mortar (for some projects)
- Tamping tool