Sacramento winters bring storms that drop a lot of rain in short bursts. Bare soil on slopes or new beds can wash away quickly. Yard erosion control keeps that soil in the yard and out of gutters and storm drains.
Most erosion problems share a few causes. Bare soil, fast moving water and slopes without roots to hold them together are the usual suspects.
When a Site Needs Yard Erosion Control
Look for small channels cut into soil after rain. Soil piled at the bottom of slopes, muddy water leaving the property and exposed roots also signal erosion. Mulch that washes into paths or piles against fences is another clue.
Sites under construction face extra risk. Grading, demolition and trenching leave large areas of loose, bare soil.
Why Bare Soil Erodes
Raindrops hit bare soil hard and break apart surface crumbs. Loose particles then move with runoff. As water speeds up on slopes, it carries more soil.
Clay soils add another twist. Water soaks into clay slowly, so more of it runs across the surface.
Mulch as a First Defense
UC IPM notes that mulch reduces compaction and erosion caused by irrigation, rainfall and foot traffic. A layer of organic mulch shields soil from raindrop impact. It also slows water so more of it soaks in.
Gravel and crushed stone work as mulch too. UC IPM suggests placing landscape fabric under rock mulch so soil and rock do not mix.
Plants With Fibrous Roots
The UC IPM page on landscape design and water quality notes that dense plantings with fibrous roots along edges reduce runoff and erosion. Roots bind soil while leaves and stems slow water. Ground covers, grasses and low shrubs can serve this role.
Plant slopes during the cooler months so roots grow before summer. The post on Sacramento planting seasons covers timing.
Slowing Water on Slopes
Long, straight slopes let water gain speed. Breaking them up slows runoff. Planted terraces, rock check dams in small channels and mulch berms are common methods.
UC lawn soil preparation guidance warns against steep slopes or berms that increase runoff. Gentle grades shed less soil than steep ones, and they are easier to plant and maintain.
Swales and Rain Gardens
UC IPM describes swales as long, shallow grassy depressions that guide water. Rain gardens are low areas that hold water briefly so it can soak in. Both slow runoff and filter sediment.
Plants in rain gardens must survive both wet and dry conditions. Choose species suited to that cycle.
Porous Surfaces
Hard surfaces such as concrete and asphalt shed nearly all the rain that falls on them. That runoff often erodes nearby soil. UC IPM suggests porous materials such as flagstone, interlocking pavers or pervious concrete for walkways and patios.
Gravel paths let water soak in as well. They also give foot traffic a place to go besides bare soil.
Managing Roof Water
Downspouts release a lot of water in one spot. That flow can cut channels in beds and slopes. UC IPM suggests rain barrels for rooftop runoff and directing water to planted areas.
Splash blocks and extensions spread the flow. Rock lined channels can carry water across a slope without cutting it.
Drains for Problem Areas
Some sites need drains to carry water away. Surface drains collect water at the top, while french drains move it through gravel underground. The post on french versus surface drains compares the two.
Checking Soil Drainage
Slow draining soil increases runoff. A quick percolation test shows how fast water moves into soil. The post on running a soil drainage test explains the method.
Erosion During Construction
Projects that strip plants or move soil should plan erosion control before work starts. Cover stockpiles with tarps, keep bare areas small and mulch as soon as grading ends. Fiber rolls or silt fences can catch sediment at the edges of work areas.
Larger projects may need permits with erosion rules. Check with the City of Sacramento before major grading.
Retaining Walls on Steep Slopes
Some slopes need walls to hold soil. The City of Sacramento lists retaining walls among projects that need a permit, with an exemption for walls not over 4 feet from footing bottom to top unless they support a surcharge. Wall design affects drainage behind the wall too.
Tall or loaded walls need engineering. Ask a licensed professional before building.
Keeping Soil Out of Storm Drains
Sediment that leaves a yard flows to storm drains and local waterways. Sweep soil off walks and driveways rather than hosing it into the street. Keep piles of soil and mulch away from gutters.
Mulch Near Trees
Mulch helps on slopes under trees, though it should stay back from trunks. UC IPM advises keeping organic mulch 6 inches or more from trunks. The post on tree mulch volcanoes shows what goes wrong.
Irrigation and Erosion
Sprinklers can erode soil as surely as rain. Heads that spray onto slopes faster than soil absorbs water send runoff downhill. The City of Sacramento does not permit irrigation runoff at any time.
Drip irrigation or soaker hoses apply water slowly at the soil surface. Shorter cycles with breaks between them help water soak into clay on sprinkler zones.
Foot Traffic on Slopes
Paths worn into slopes become channels for water. Steps, stepping stones or a defined path keep people on one route. Plant the rest of the slope densely so it stays covered.
Erosion After Tree or Shrub Removal
Removing large plants leaves bare soil and loosened roots. Those spots often wash out in the next storm. Mulch or replant them soon after removal.
Ongoing Maintenance
Check slopes after each big storm. Refill thin mulch, repair small channels and replant bare spots. Early fixes keep small problems from growing.
Keep a simple log with photos from each storm season. Patterns show which areas need stronger measures, such as denser planting, a swale or a drain.
Yard erosion control succeeds as a mix of cover, plants and water management. More site topics sit in the site preparation category.