Sheet Flow Construction Erosion Control

December 10, 2020

Infiltration Berm

I call these infiltration berms. They aren’t berms like the others in this presentation but they function the same way-they contain water, divert water, or both.

The first two photos show created berms and the last is a utility trench that has not been paved yet. The first two were installed to contain the dirty runoff from muddy shoreline rip rap that we had to remove to install piling.

The berm surrounds about two acres of paved surface. The asphalt was removed to expose the subgrade to allow runoff to infiltrate. These can be designed but we didn’t have time.

To do this correctly, you should figure out how much runoff you will have, how much storage volume to create (this determines how long and how wide the trench is) and the actual infiltration rate of the subgrade.

The last photo shows how you can use your site to your advantage.

Presentation: David Jenkins-Sheetflow Erosion Control
Presentation: David Jenkins-Sheetflow Erosion Control
Presentation: David Jenkins-Sheetflow Erosion Control

April 21, 2020

Hot Mix Asphalt Berm

Photo: David Jenkins

The work area is the left. All runoff is diverted by silt fence and this hot mix asphalt berm to a sump, where it is pumped to a chitosan-enhanced sand filtration treatment system. This system prevented all turbid site water from entering the roadside ditch-outside of the silt fence-from draining to a creek. Note the mud on the left side of the berm and the clean asphalt on the right.

Since this is summer work and perimeter BMPs are containing all site runoff, we are not covering bare soil.

Upon completion and soil stabilization, the asphalt berm will be removed and hauled to an asphalt batch plant for recycle.

January 15, 2020

Who Needs BMPs?

Video: David Jenkins

I found this small project in Kanab, Utah. It almost seems like someone asked, “Who needs BMPs?”

January 14, 2020

Where’s the Rock Entrance?

Photo: David Jenkins

Where’s the rock entrance? I am just glad it’s not my project. This is a small staging area for a bike path extension next to a creek. All dirty runoff ends up in the creek. There used to be a rock entrance, but with mud being tracked over it, it has disappeared. With a small staging area and rainy season work next to a creek, I would have specified that the entire staging area be covered with Asphalt Treated Base (ATB), to be removed and recycled at the end of the job. I have done this on several staging areas of up to about two acres. This can end up being much less expensive than managing tire washes and sweepers.

November 26, 2015

Rainy Season Preparation

Dirty Water Flowing in Ditch

Preparing for the Rainy Season
David S. Jenkins
WSDOT Statewide Erosion Control Coordinator
September 1997

Now that the El Nino has ended and the La Nina has begun, the National Weather Service is predicting a much wetter fall and winter than normal. So, what are some things you can do now to prepare? How about: (more…)

November 26, 2012

What You Can Do to Control Erosion and Protect Your Property

Before and During Construction

Plan construction activities during spring and summer, so that erosion control measures can be in place when the rain comes.
Examine your site carefully before building. Be aware of the slope, drainage patterns and soil types. Proper site design will help you avoid expensive stabilization work.
Preserve existing vegetation as much as possible. Limit grading and plant removal to the areas under current construction. (Vegetation will naturally curb erosion, improve the appearance and the value of your property, and reduce the cost of landscaping later.)
Use fencing to protect plants from fill material and traffic. If you have to pave near trees, do so with permeable asphalt or porous paving blocks.
Preserve the natural contours of the land and disturb the earth as little as possible. Limit the time in which graded areas are exposed.
Minimize the length and steepness of slopes by benching, terracing, or constructing diversion structures. Landscape benched areas to stabilize the slope an improve its appearance.

As soon as possible after grading a site, plant vegetation on
all areas that are not to be paved or otherwise covered.
Control dust on graded areas by sprinkling with water,
restricting traffic to certain routes, and paving or graveling
access roads and driveways.

Temporary Measures to Stabilize the Soil

Grass provides the cheapest and most effective short-term erosion control. It grows quickly and covers the ground completely. To find the bet seed mixtures and plants for your area, check with your local nursery, the U.S. Department of Agriculture Soil Conservation Service, or the University of California Cooperative Extension.

Mulches hold soil moisture and provide ground protection from rain damage. They also provide a favorable environment for starting and growing plants. Easy-to-obtain mulches are grass clippings, leaves, sawdust, bark chips and straw. Straw mulch is nearly 100% effective when held in place by spraying with an organic glue or wood fiber (tackifiers), by punching it into the soil with a shovel or roller, or by tacking a netting over it. Commercial applications of wood fibers combined with various seeds and fertilizers (hydraulic mulching) are effective in stabilizing sloped areas. Hydraulic mulching with a tackifier should be done in two separate applications: the first composed of seed fertilizer and half the mulch, the second composed of the remaining mulch and tackifier. Commercial hydraulic mulch applicators – who also provider other erosion control services – are listed under “landscaping” in the phone book.

Mats of excelsior, jute netting and plastic sheets can be effective temporary covers, but they must be in contact with the soil and fastened securely to work effectively.

Roof drainage can be collected in barrels or storage containers or routed into lawns, planter boxes and gardens. Be sure to cover stored water so you don’t collect mosquitoes, too. Excessive runoff should be directed away from your house. Too much water can damage trees and make foundations unstable.

Structural Runoff Controls

Even with proper timing and planting, you may need to protect disturbed areas from rainfall until the plants have time to establish themselves. Or you may need permanent ways to transport water across your property so that it doesn’t cause erosion. To keep water from carrying soil from your site and dumping it into nearby lots, streets, streams and channels, you need ways to reduce its volume and speed. Some examples of what you might use are:

Riprap (rock lining) to protect channel banks from erosive water flow.
Sediment trap to stop runoff carrying sediment and trap the sediment.
Storm drain outlet protection to reduce the speed of water flowing from a pipe onto open ground or into a natural channel.
Diversion dike or perimeter dike to divert excess water to places where it can be disposed of properly.
Straw bale dike to stop and detain sediment from small unprotected areas (a short term measure)
Perimeter swale to divert runoff from a disturbed are or to contain runoff within a disturbed area
Grade stabilization structure to carry concentrated runoff down a slope

From Association of Bay Area Governments:

May 4, 2012

Dirty Water Runoff Final BMPs

Video: David Jenkins

In this last video of the series, I inspect dirty water runoff and show the final BMPs.

April 27, 2012

Dirty Water Runoff Temporary BMPs

Video: David Jenkins

In this video, I continue the inspection of dirty water runoff and identify temporary BMPs.

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