Sheet Flow Construction Erosion Control

October 13, 2020

Plastic Covered Slope

Here is a nice, plastic covered slope. They have placed sand bags on the seams, the seams are overlapped at least 12 inches and the plastic is run all the way to the bottom of the slope. This is a riverbank habitat restoration project on the Duwamish Waterway.

Video: David Jenkins

September 30, 2020

Slope Covered with Plastic

View of slope on Site 25 Habitat Restoration Project. Photo: David jenkins

We have covered a slope above the Duwamish Waterway with plastic until landscaping occurs in December. The contractor has done a great job overlapping the plastic sheets and securing them with sand bags.

September 8, 2020

Biodegradable Wattles

I wrote this biodegradable wattles specification for a riverbank habitat restoration project.

I wrote the last three sentences for this particular project, which has a 2:1 slope above an intertidal river. We will place 12 inches of compost before installing native plants this winter; without the wattles, wet compost will slide to the base of the slope.

BIODEGRADABLE WATTLES

  1. Wattles shall consist of 100% biodegradable straw, coir, excelsior or compost encased in 100% biodegradable fabric or mesh.
  2.  Wattles shall be a minimum of 8 inches in diameter free of cuts tears and damage.
  3. The installation of straw wattles shall be per WSDOT Standard Plan I-30.30-00 “Wattle Installation on Slope”.
  4. Wattles shall be staked in place using wooden stakes a minimum of 16 inches long.  The stakes shall be cut flush with the top of the wattles.
  5. Wattles shall be installed on the Site 25 slope above +12 elevation.
  6. Wattles shall be installed in two rows across the slope parallel to the 12 + elevation. 
  7. Rows shall be approximately 7 feet above the +12 elevation and 7 feet below the top of the slope.

December 25, 2019

Merry Christmas 2019

 

Merry Christmas 2019!  What do I do when I am on vacation?  Take videos of erosion control, of course!

Erosion control blanket was installed on this slope in southern Utah about 6 years ago. The biodegradable material has degraded. The photodegradable netting is still intact, seemingly just as strong as new. The slope is south-facing, the area gets over 300 days a year of sun; what’s the deal? How long will this stuff last in the environment? I only specify 100% biodegradable erosion control blankets; this is one reason why.

December 24, 2019

Shortening Slope Length

Video: David Jenkins

In this video, I discuss shortening slope length with coir logs installation methods.

October 31, 2019

Is This Silt Fence Necessary?

photo: David Jenkins

Is this silt fence necessary? Overlooking the fact that this silt fence installation needs some maintenance, I wonder if it was ever really needed in this location? The slope grades to the fence are minimal and not very long, and the roadside ditch line is graded so that water will drain away from the road.

This type of silt fence installation is appropriate at the base of long, steep slopes, or if there is risk of sediment travelling off site. Also, all of the materials used will likely be land filled and not reused, including the wire backing and the “T” posts.

If this were my site, I would have installed orange safety fence with steel “T” posts, maybe with a compost berm along the base, on the project side. The safety fence can be easily removed and reused later, and the compost could be raked into the ditch line and hydroseeded.

February 15, 2018

Straw Wattles Reduce Erosion

Straw wattles reduce erosion when placed on a slope, on contours and at regular intervals.  They will intercept flowing water, reducing its velocity and reduce erosion. Straw Wattle Installation Drawing


Video: David Jenkins

January 13, 2016

Plastic Sheet

Plastic sheet is a good, temporary practice you can use to protect soil from soil erosion and sediment loss from a slope.

When used, you need to make sure that the plastic is installed so that all the clean rainwater that runs off doesn’t end up dirty because it ran onto bare soil.

The clean water needs to be collected and piped away from the bare dirt, or the plastic needs to be run all the way to the bottom of the slope into a stable ditch covered with grass, erosion control blanket, rock or other soil erosion prevention measure.

Video: David Jenkins

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