Sheetflow Erosion Control Erosion Control for the CESCL

October 8, 2020

Planning Ahead

Filed under: Video — Tags: , , , , , , , — Sheetflow @ 3:40 am

Planning ahead requires a different mindset to prevent problems rather than react when they happen.

On this project we are using the neighboring property for staging; all of the runoff drains into their constructed stormwater treatment swale.

Their stormwater discharges are regulated and any non-compliance issues could be attributed to the contractor’s use of this area.

Video: David Jenkins

September 21, 2020

Steel Plate Construction Access

Video: David Jenkins

This is a steel plate construction access that we built across a live stormwater swale. We have installed compost socks along the edge to keep construction runoff out of the swale.

August 17, 2020

Adaptive Management-Perimeter BMPs

There is a difference between the paper erosion plan and what the project looks like in the field. I wrote up the plan to manage water from offsite. Now that I am looking at the area, I might need to re-think the plan. Erosion control adaptive management is what makes the plan come to fruition. Video: David Jenkins-Sheetflow

This video gives an example of adaptive management for perimeter erosion control BMPs.

Transcript:

This is our staging area for our project we are going to be starting up back over in here on the other side of a stormwater swale. We have to access the site through another owner’s property and they have allowed us to have this staging area.

My plan was to have an extruded asphalt curb along this edge to take all the stormwater running off the parking lot coming this way and keep it out of the staging area, but that’s going to concentrate all the water from back up to the left into one location there down by the equipment.

Another BMP we’re using is compost socks on the edge of the swale to take any sheet flow from the staging area here and spread it out before it goes into the swale. Here are the compost socks and a bunch more here waiting for installation.

The idea of concentrating all the water and dumping it into the swale in one spot down here, maybe its better with the compost sock to just let everything just sheet flow and spread out against the sock and then dribble in, and actually in this area its not going right into the swale its going into some landscape across the pathway and then into the swale so maybe it’s a combination.

Actually, come to think of it, maybe on this end of the project no curbing and back over in here we put curbing in. This is all pretty protected so you know, this is adaptive management, this is how these things go you do the erosion plan write it up on a plan sheet and then you walk the site and see how things are in reality and should be willing to change.

Okay from here now from this pathway over we are going right into the swale so maybe we start the curbing maybe off this island. You see were gong into the swale now and this is going to be the most intensively used area for staging so maybe we start with a short, extruded asphalt curb over there and let everything else sheetflow back in here.

Okay got to think on this.

April 7, 2020

Silt Fence Water Bars Fail

Photo: David Jenkins

Whenever I see something like this, it makes me think that the site owner/contractor either didn’t know what they were doing or bit off more project than they could chew, or both. These guys cleared, grubbed and graded something over 80 acres starting in late summer, failed to phase the work, failed to use soil cover practices, failed to listen to the experts and got nailed by the fall rains.

Erosion control is really about water control: reducing volume, preventing it from becoming turbid, and controlling where it goes. By the time the rains hit this project, there was too much water, it was too dirty, and there were too few options for controlling where it went.

In addition, they refused to set up a chitosan-enhanced sand filtration system to treat and discharge water; this left them no options and too much turbid water that had nowhere to go. As a result, they hammered a wetland, were fined heavily, and were shut down for months.

Silt fences are not meant to control water, convey water, filter water; they are designed to control eroded sediment. Ditches, berms (rock, gravel, triangular silt dikes, etc.) would have been better choices at this location. Not opening up so much area so late in the season would have been the best option. Their means and methods did not save them time or money.

April 6, 2020

Silt Fence and Trackout Fail

Photo: David Jenkins

I was just minding my own business last Friday, driving from Fred Meyer to the UPS store and passed this project. I told my wife I have to get a photo; she says okay since she knows me and my habit of stopping to take TESC photos.

I made a u -turn at the Wal Mart, drove back a block and stopped in the middle of the street to get this shot.

There is so much wrong here, where do I start? Clearly, dirt is tracked off of the project in the background, as you can see the sediment build up in the curb line. Someone told someone to put something in the swale to keep dirt out, then someone else installed this silt fence.

First off, silt fence needs to be trenched in and this just has a few rocks placed on the flap.

Second, they probably couldn’t trench this in anyway without tearing up the drainage swale.

Third, only two of the three curb cuts are backed by the silt fence.

Fourth, silt fence is a barrier, not a filter, and with the volume of water draining off the asphalt during a rain event, dirty water would just blow around and under the silt fence.

Conclusion, silt fence is never used in a water flow situation; it is only to contain eroded sediment from a sloped area. A better BMP here is a compost berm or something similar that would allow some water to pass but filter some sediment. Sand bags would work to keep everything out of the swale but then the dirty water would bypass to the next catch basin, which probably has a catch basin insert, which would collect sand and such but would not do anything for turbidity. So, what is the best BMP? Stop the !@#$ ing trackout in the first place!

September 3, 2019

Temporary Irrigation

Video: David Jenkins

When we need to get grass to grow quickly, especially in the summer, we set up a temporary irrigation system.

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: www.abag.ca.gov/bayarea/enviro/erosion/eyoudo.html

Powered by WordPress