Erosion and Sediment Control
Half-Day Training Course
Erosion Control on the Transition: What's Done Between Phases
In the best situations, the approved sediment and erosion control plan for mass grading sites include perhaps a few distinct construction activities: 1) demolition, 2) clearing and grubbing, 3) grading 4) Installation of permanent stormwater measures/devices, and 5) vertical construction of buildings. The misconception that an erosion and sediment control plan with these distinct construction activities can be represented with one phase in an erosion control plan submittal is short sighted. The thought that this “one size fits all” or “one phase fits all conditions” erosion control plan is adequate to address mass grading with overland flow conditions lasting many months and possibly years through phases 2-4 previously mentioned, is certainly more than short sighted. It is time for all personnel involved in the construction process to put on their “thinking caps”! Let’s begin this discussion by looking at the Erosion and Sedimentation control plan and the review of that plan.
Begin with a strong foundation - an erosion and sediment control plan and construction sequence that includes selective clearing/timbering to install vegetated top dewatering basins along the project perimeter, stable temporary runoff conveyances, and a vegetated buffer upstream of perimeter silt fence. Preserve the trees cleared to create single shredded mulch to be used as groundcover through the life of construction. We will continue with addressing critical areas on the projects such as temporary stream crossings with smaller storage structures, stable runoff conveyances, vegetation, and stone approaches. We will minimize the voids and tie-ins along the project perimeter with the mulch we preserved. This plan would be supported with necessary calculations and address other items of concern such as stockpiling, staging, material laydown, etc. such that the Regulatory agency reviewing the plan has fewer comments and gets a plan that is approvable. We believe that the approved plan would also address the use of rolled erosion control product on perimeter slopes as this will can play a big role in the success of perimeter measures.
After achieving the approved plan, implementation of this plan is key and this is where the “erosion control transitioning” begins to play a vital role to successful erosion control and sediment containment onsite. Although the engineers will remind the regulators that specifying means and methods will not occur on this project, all parties rely on the contractor to make that erosion control plan work on the ground. Does it matter if the site has rock everywhere including in the basin locations? Does it matter if there is a ½-1 inch rainfall event every few days? Does it matter that he has a large amount of excess soil and parts of the site to be elevated 30ft or more? Does it matter that the performance time from demolition to installation of the permanent storm drainage will last 11 – 18 months? Well of course it matters to the contractor in the field, but the regulator expects containment and the plan to be implemented no matter what the temporary grade is between phases. That is where the true erosion control story begins and where we rely on the grading contractor to read between the lines. We will discuss some of the intermediate erosion control measures that could and should be used as erosion control implements to be stored in the contractor, engineer, and regulator toolbelts. And, we will conclude our discussion with the monitoring that should be performed to ensure continued success through the life of the construction project.