Sheetflow Erosion Control Erosion Control for the CESCL

December 18, 2020

Prepare for Fall and Winter Rains by Preventing Erosion

This is a blast from the past. I think I wrote this in 1996 with I was the first State-wide Erosion Control Coordinator at the Washington State Dept. of Transportation.

Preventing erosion is the best preparation.  Here are some things to consider when you prepare for fall and winter rains:

Cover bare soil. Final grades can be covered with hydroseed, erosion blankets, topsoil, bark or whatever final cover is planned for the project.

Get your hydroseed contractor lined up now and avoid the October rush.

Don’t open up more than a few acres after September 1st.

Grades that aren’t being actively worked can be covered with straw at a rate of 3000 pounds per acre. This is a very cheap and effective way to protect bare soil from raindrop impacts and erosion. Hand seed before spreading the straw. Spray it with water to help hold it in place.

Track your slopes with a Cat: up and down slope, not across slope. The first helps prevent erosion, the second speeds it up.

Use flex pipe drains at bridge ends if your permanent drainage system and curbs are not in place. Collect the water from the bridge using sand bags and divert it to the pipe. Make sure the pipe is long enough to reach the bottom of the slope.

Another good way to prepare for fall and winter rains is to use a water truck and water seeded areas weekly to get quicker growth. The better the growth going into winter the better.

If you have to open up a large area, only clear and grub small areas. You can clear larger areas if you don’t grub. Roots and slash help protect the bare soil.

Walk the site looking only at erosion controls, thinking ahead of areas that could have a problem. Identify them and start making additions and corrections.

Locate all existing water flows in and around your project and find out where they drain to.

Think about maintenance and regular inspection of erosion controls. When are silt fences going to be inspected and who does it? Who removes mud from check dams? Who covers slopes with straw or other mulch?

Get materials on site now. Again beat the rush for materials in October and November when everyone is in a panic to get plastic and straw. Stockpile enough straw, plastic, silt fence, flex pipe, sand bags, seed, rock, now to cover all areas that are bare.

Set up emergency procedures now. Who should be called in emergencies? Do you have a Certified Erosion and Sediment Control Lead (CESCL)? Brief your personnel on what to do if they see muddy water and who to go to.
Make sure that erosion control material installers know proper installation methods.

Make sure all your silt fence is installed on contour with the ends flared up slope a few feet. If it is not on contour, identify the lowest points of the fence as these will be the failure spots. Install a double row of silt fence at these low spots before you have a failure. Double up your silt fence in areas where eroding slopes could flow into wetlands or streams.

Do you have bare spots where previous seeding hasn’t grown? Cover it with seed and straw if the area is small, remobilize the hydroseeder for larger areas.

Make sure all catch basins within the project boundary are protected with inserts, fence surrounds, or other methods to keep mud out. Locate any catchbasins outside project boundaries that may receive water from your site and protect them.

Make sure that you have a copy of the  Temporary Erosion and Sediment Control plan (TESC) and any grading or environmental permits on site in the job shack. Know what they say. Give each inspector a copy of the TESC to keep in their truck. These are working copies that can be adapted to site conditions.

Modify your permanent stormwater ponds into temporary sediment ponds by installing a standpipe and blocking the outlet with sand bags. Cut a few small holes in the standpipe to allow for slow release of water. You can also use perforated pipe as the standpipe and hold it in place with “T” posts, wire, and gravel piled up around it.

Use geotextile fabric as a temporary ditch lining to protect bare soil from erosion. Hold the fabric in place with rock check dams, wooden stakes, or sand bags.

Make sure that all check dams are installed so that the top center point is lower than the bottom end points. This prevents end-cutting. You may have to add more material to the dam to increase the width, especially on wide ditches with shallow grade side slopes.

Now you know how to prepare for fall and winter rains: Prevent Erosion

July 6, 2020

Perimeter Control BMPs

Photo: David Jenkins

The contractor is using silt fence and an asphalt berm as perimeter control BMPs. They are containing all sediment and water within the project. When it rains, the contractor pumps stormwater runoff to an on-site treatment system, which uses chitosan-enhanced sand filtration.

June 22, 2020

BMP Graveyard-Coir Blanket

Photo: David Jenkins

Heavy duty coir coconut mesh blanket left in the sun for five years. It is still functioning as soil cover but has no strength left and is easy to pull apart.

June 18, 2020

Rock Construction Entrance

Photo: David Jenkins
Photo: David Jenkins

You can’t ask too much of a rock construction entrance. We installed this according to the state stormwater manual. You have to keep tires clean or you will get trackout.

June 17, 2020

Silt Fence Overlap

Photo: David Jenkins
Photo: David Jenkins

This is one option for splicing two pieces of silt fence together. Fortunately, this is a low risk application around a short term Groco compost stockpile.

June 12, 2020

Embankment Fill Design

Photo: David Jenkins

This is how we designed and constructed embankment fills for the 3rd Runway project 15 years ago. We sloped the benches and the top surface to drain water away from the face.

June 11, 2020

Phasing a Stockpile Project to Prevent Dirty Runoff From Draining to Wetlands

Image: David Jenkins

Phasing a Stockpile Project

Phase 1-

(A) Install silt fences on perimeter and at base of future stockpile.

(B) Clear, grub, grade, construct drainage ditches and temporary stormwater pond including outlet structure and perforated pipe level spreader drains. Grade to drain water away from outer perimeter silt fence and toward ditch.

(C) Hydroseed and install blankets in ditch line.

(D) NOTE: Background stockpile, built later, used an early generation construction stormwater treatment system and discharged to creek instead of level spreaders into vegetation.

Phase 2-

(A) Place and compact fill material to approximately 20 feet of vertical elevation.

(B) Trackwalk and hydroseed slope.

Phase 3-

(A) Same as Phase 2.

(B) Same as Phase 2.

Phase 4-

(A) Place and compact fill material to approximately 20 feet of vertical elevation. Start base of slope 15 feet in from lower fill and grade to drain away from lower slope and to the stormwater pond.

(B) Trackwalk and hydroseed slope.

(C) No hydroseed on top of the pile as material is continually brought in as available.

January 16, 2020

Straw Blanket Netting

Photo: David Jenkins

I saw this straw blanket netting while hiking at Twanoh State Park. The access road had some erosion issues and straw blankets were installed to cover roadside cut slopes. This work was accomplished about 4 or 5 years ago. Notice that the straw is gone but the plastic netting remains. 100% biodegradable netting is the way to go.

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.

November 12, 2019

Hydroseeding on Blanket Instead of Under Not the Best

Hydroseeding on blanket  is not the best way to get grass growing. The seed sits on the blanket which is a quarter to half inch above the soil. Since the seed needs to be in contact with the soil to have the best chance of growing, this will reduce the quantity of grass that grows. In a ditch, the more grass the better. The best way is to hydroseed first and then install the blanket.

 

Video: David jenkins
Older Posts »

Powered by WordPress