How to Create a Backyard Gully
Building a backyard gully is often a matter of necessity. An overflow of storm water may already be cutting a gully across your property and damaging the landscaping. Rather than allowing erosion to destroy your property, build a dry stream-type gully to enhance your garden as well as control excess runoff. By directing water away from your home's foundation in a controlled flow into the municipal flood control system, you may avoid expensive remedies such as building retaining walls to stabilize a sloped or hillside property. Does this Spark an idea?
Other People Are Reading
Things You'll Need
- Measuring tape
- Graph paper
- Garden hose
- Shovel
- Level
- Rake
- Plate compactor
- Pond liner
- Sand
- River rock
- Pea gravel
- Naturalizing bulbs
- Wildflowers
- Native plants, shrubs and trees
- Mulch
Instructions
-
The Plan
-
1
Consult with the local building permit office and water resources agencies if your gully drains into a watershed, marsh or waterway. There are strict regulations regarding water runoff from private property. Contact local utilities to locate any underground cables and water, gas or sewer lines.
-
2
Discuss your project with your neighbors if your backyard gully will affect the runoff or drainage onto their properties. Most building regulations forbid changing the natural flow of water on or off your property. If your neighbor is facing a similar challenge, perhaps you can work together to avoid erosion to both properties.
-
-
3
Measure the area where you plan to build the gully. Draw a simple plan of your property to scale on graph paper. This lot plan is usually necessary if permits are required to excavate the gully. Show the locations of the house, fences, existing hardscape and plantings as well as the proposed gully. The plan should also show the drop, or slope, of the gully from the lot to the street or storm drain. Generally, a backyard gully should measure twice as wide as its depth, with rounded sloping sides to avoid erosion.
-
4
Indicate with arrows the drainage from the property into the gully on the plan. Also indicate the direction the gully will drain to the street, storm drain or drainage canal. Use the natural lay of the land to enhance the effectiveness of the completed project.
Building the Gully
-
5
Outline the gully with a garden hose. If you are installing an additional swale to direct excess storm water into the gully, also mark it with a garden hose or landscaper's spray paint. A swale is a long, shallow depression in the yard that directs water from low spots or away from the house foundation and into the gully. It is usually between 6 and 12 inches deep and 2 to 3 feet wide. The sides are slightly sloped; you can mow over most swales.
-
6
Remove the grass and soil from the gully. Excavate an extra foot of soil to accommodate the sand and rocks that will line the gully. Use a level to ensure that the gully slopes continuously to the drainage below. Round the top edges of the gully; knock off any sharp edges or drops. The slope and sides of the gully should be as rounded and shallow as possible to diffuse and slow the speed of the water draining from your property.
-
7
Smooth the sides and bottom of the gully with a rake. Some building departments require a pond liner to enhance the flow of water through the gully. Remove sharp rocks and branches that may tear the liner.
-
8
Add 4 inches of sand to the bottom of the gully. Spread the sand by raking it smooth across the bottom of the gully and drawing it up the sides. Sprinkle with water and tamp firmly to provide a smooth, solid base for the liner.
-
9
Open the pond liner and spread it over the bottom of the gully. Begin at the bottom of the slope and work your way up the hill, rolling out the liner and spreading it evenly over the compacted sand. Overlap sections by 3 feet to avoid leaks.
-
10
Fill the bottom of the gully with smooth river rocks. Vary the sizes, placing the largest rocks in the bottom of the gully. Work from large to small, from the bottom up the sides to where the edges of the gully meet the landscaping.
-
11
Add 2 inches of pea gravel along the edges of gully, up to the surrounding plantings. The water flow in a natural stream spreads the river rock in a similar manner. The large, heavy rocks sink to the bottom and the smallest stones are concentrated along the sides.
-
12
Plant naturalizing narcissus, iris, ferns, native grasses, wildflowers, shrubs and small trees along the sides of the gully to provide a natural appearance from the house and yard. Cover the planting beds with shredded mulch to help slow the flow of water into the gully.
-
1
Tips & Warnings
Hire a Bobcat or backhoe operator to dig the gully for you.
Recruit family members and friends to help you arrange the river rocks and plant the new landscape.
Have all materials delivered by the vendor. The average homeowner's van or truck is not built to carry tons of landscaping materials.
Add a pond by digging a 3- to 4-foot depression in the gully and lining it with a pond liner. Install a pump and filter to keep the pond clean.
Consult the local agricultural extension office for advice on plants, shrubs and trees that will thrive in your climate.
Don't build a gully to drain water from your property without consulting the proper agencies. Large fines are often levied on homeowners who ignore water resources agency regulations.
Avoid cutting into steep slopes or undercutting the banks of the gully. Workers who are accidentally buried in sand or soil do not have a high survival rate.
Consult a professional landscaping firm, building contractor or geologist when working on a steep slope. You do not want to cause a landslide when the winter rains arrive.
Do not use pesticides or fertilizers in your yard if your gully drains into the watershed.
References
Resources
- Photo Credit Jupiterimages/Photos.com/Getty Images
