Erosion control for your home and garden
Last updated 12/6/2007 at Noon
Do you have a slope on your property where rainwater flows, causing erosion, or have a landscape drainage problem? With the recent firestorms, the possibility of erosion of soils, slopes and property damage has come to the attention of homeowners in a major way. Here is some information that might assist you in evaluating the environmental setting around your home in regards to erosion and what can be done about it.
It is important to understand a little about the terrain around your property and the lay of your land and how it could affect neighbors. How the grading or sloping on your property will impact the lay of the land is very important to how you approach the use of various techniques for erosion control.
When you take soil and water and blend them together you get mud. Great for kids’ mud pies, but maybe not so great for Mom and Dad. Bare and wet soils can have a major impact about your home and can cause short- and long-term land and structural damage.
Water should not be allowed to cascade uncontrolled down long or steep slopes that have been disturbed or graded. When pounding rains impact bare soils, there is going to be a cause and effect on what happens. Residents of hillside areas are especially susceptible to these dangers.
When bare earth is covered in different ways, this disperses the water droplets and allows for a more gentle impact onto the soil. It is valuable to know a little about the course of water and runoff around your home, and then you can set a plan on how to control it without having damage to home and property. Unleashed water can be very dangerous.
There are many traditional erosion control products today and some not so traditional that can save your home and property from erosion. Here is a brief listing to consider.
Generally, this is what is most commonly employed for a quick fix of erosion problems. Bags are made of either burlap or plastic and filled with sand, then stacked accordingly for the problem areas.
When stacking the sandbags at the bottom of a slope, one should incline the bags toward the angle of the slope so as not to create a weak wall. The bags should also be overlapped to build some added strength and stability.
This is plastic sheeting about three feet wide and various lengths that can be placed at the top of a slope or a problem area. It helps somewhat in catching some degree of silt or eroded soil and small debris.
This product is not strong and is used for minor control but can be employed along with other methods and must be staked.
These are used to act as a physical barrier and installed as a wall to help stop runoff somewhat or deflect the water in a specific direction. The bales should be installed end to end and heavily staked into the ground with long wooden stakes or metal rebar.
This is referred to as a landscape fabric and comes in assorted widths and lengths. It is biodegradable jute that can be rolled onto slope or problem areas.
It has quarter-inch openings and as a blanket by itself can help soften the impact on the soil from rains. It is overlapped and secured into the earth by pins like long bobby-pins.
A value of the netting is that it can be easily cut and opened up and planted with either strong ground-covers or properly chosen shrubs or trees.
Straw tubing or wattles
This is a product fairly new to the landscape industry.
It comes in rolls. The outer netting holds the straw material inside, like a sausage. The wattle is then staked into the ground in various areas where erosion is a problem.
It is best to dig a small trench along a slope to aid in the securing of the tubing and help catch small amounts of erosion debris.
The distance between the straw wattle-tubing lengths is governed by the degree of the slope; the steeper the slope, the closer the wattles. On flatter areas, doing a contour installation has merit for soil retention.
Where there is a larger problem area of a swale or a gully, the use of rip-rap (blasted stone) has a great impact on saving and repairing your land. Truckload qualities for larger problems are available from your local stone yard and some aggregate companies.
The rocks are laid loose and not mortared in order to have some percolation, which slows down the rate of the flow somewhat. This is good for streams/gullies, small or washed-out areas.
Handsome and creative dry streambeds can be installed into problem areas and can be both functional and aesthetic to the overall garden’s appearance.
This approach is fairly basic but can be a quick fix in certain situations.
The sheeting is applied to the problem areas and pinned down or secured with the aid of sandbags. The edges all have to be secured properly so if a strong wind comes along your effort, time and money don’t take off into the horizon.
It is important to understand that various degrees of wind are usually associated with rainstorms, so make sure any form of tarping is properly installed and secured.
This is sometimes a very valuable approach to utilize but must be installed long before the rainy season in order to make it cost-effective and efficient.
This technique is where a slurry of organic fiber (wood shaving material), along with a specific seed mix and water, is sprayed onto the area of erosion potential.
The selection of the seed mixture is wide and varied, but the key is to get deep-rooting plants into the blend of the mixture. Clovers, vetch, legumes and rye grass all have value to be incorporated into the blend.
Added perennials and annuals can enhance the appearance, but a lot of these are just pretties that can be combined into the seed blend.
Specialized mixtures of drought-tolerant plants, native grasses or shrubs and trees also can be another approach. Usually, this application is done in fall before the rainy season, but one cannot depend entirely that the rains will come and to what degree of effectiveness in order to germinate the seed mixture.
Irrigation systems usually need to be installed prior to the hydro mulch process, but it’s worth the investment.
There are copolymers that have been employed in landscape applications and can bind soils to make them more stable. These products are blended into soils and small aggregate, rototilled, moistened and compacted, changing the structure of the soil or small aggregate to be more stable and solid.
This application is wide and varied, from dust control, erosion control, driveways, paths and recreational fields, both for residential and commercial installations. It is even being currently employed in Iraq today for dust control on helipads and roads.
Drainage pipe/culverts/catch basins
These are all mechanical methods that can also be employed in erosion control and must be installed by a professional to make sure its design and implementation is workable for water diversion/dispersal and elimination.
Plant selection for erosion control: the proper selection and planting of erosion areas is of prime concern. One must have an understanding and knowledge of choosing the correct plants to match the specific needs.
The simple placing of a good thick layer of organic mulch on the ground area can have some benefit.
This layer helps in the pounding of the rain on the soils and acts to some degree as a sponge. But if the rains are too intense this can wash away, so one must use careful judgment when using mulch.
Spreading a thick layer of straw or hay can be a quick fix as well, and if it’s fresh the nodes of the straw will send up shoots and establish a root system for holding the earth in place.
An ounce of prevention and proper understanding of the big-picture in a garden, landscape or ranch lands are vital and should always be approached professionally. Remember, water and soil erosion damage can be costly, so be prepared.
Hydrology and water management is an art and science to understand and must be dealt with properly. There are so many elements to consider in order to understand all the conditions that can exist on a given property and lay of the land.
We must not underestimate the power and force that water can have. Rainwater pollution due to soil erosion in and around your garden can add to even a larger problem for the planet. Wherever rainwater flows over streets, roofs, yards, parking lots, building sites, forests and farms there can be pollution to the environment.
We need more storage dams to capture this natural resource of rainwater to store and use for the future.
In new homes, make sure that your landscape plan has a drainage system that can handle the hardscape and the softscape areas. Gutters and downspouts can aid in the perimeter collecting of the sheet-water from roofs about the home.
Understanding the percolation rate of different soil types is also helpful early on in the garden’s layout for a drainage system. Don’t forget the good old-fashioned rain barrel to capture rainwater off the roof of your home. This water can be used for watering potted plants around your garden.
Trees aid tremendously in capturing and storing water for their own use. The tree canopy helps in the breakup and dispersal of heavy water droplets from rain. Trees can also consume large volumes of water that can be helpful in sheet-water runoff.
Editor’s Note: Roger Boddaert, a landscape designer/horticulturist and soils consultant in Fallbrook, can be reached at (760) 728-4297.