Temporary Erosion/Sediment Control Measures:
The documents submitted for our review must show a reasonable representation of all of the control measures that are anticipated to be necessary during all stages of the earth changes i.e. from the time the site is stripped of the existing vegetation until the site is permanently stabilized with a non-erode-able surface (Note: A site that has been seeded and mulched is NOT considered to be permanently stabilized until the surface area is well vegetated). The documents must include detailed drawings showing the proper use, materials, and installation of all temporary and permanent erosion/sedimentation control measures along with the requirement that the control measures be properly installed, maintained, relocated, modified, etc. as necessary to perform their intended function and be in compliance with the law.

Erosion and sediment controls are required for earth changes above the waterline to prevent sediment from entering the water.

Permanent Erosion/Sediment Control Measures:
All disturbed earth surfaces steeper than 3:1 and up to 2:1 (horiz:vert) sahll be restored with rock rip-rap or other pre-approved equivalent. No new slopes shall be constructed steeper than 2:1 unless specifically waived by the Conservation District. An Earth surface on pre-existing slopes steeper than 2:1 are to be armored with rip-rap or other pre-approved equivalent. These requirements apply to ditch fore-slopes and back slopes.

In all areas of channeled flow, if the water velocity is between 4cfs and 5cfs for a 25-yr/24hr storm, the channel shall be restored with pegged sod or other pre-approved equivalent. The sod shall extend a minimum of 1' above the channel bottom, measured vertically, or above the normal depth of flow for a 25yr/24hr storm, whichever is greatest.

In all areas of channeled flow, if the water velocity is greater than 6cfs for a 25yr/24hr storm, the channel shall be armored with rip-rap, pavement, or other pre-approved equivalent materials. The armor shall extend a minimum of 1' above the channel bottom, measured vertically, or above the normal depth of flow for a 25yr/24hr storm, whichever is greatest.

Regardless of the velocity, all areas of channeled flow having a continuous base-flow shall be permanently stabilized with rip-rap, pavement, or other pre-approved method (bioengineering is encouraged). The rip-rap, pavement, etc, shall extend above the channel bottom to the normal depth of the base-flow. The surfaces within the channel above the normal depth of base-flow must be restored according to the velocity and normal depth requirements for a 25yr/24hr storm, whichever is greatest. 

All rip-rap shall be sized such that the smallest stones will not be displaced by the water velocities resulting from a 25yr/24hr storm. The depth of the rip-rap shall be 1.5 times the smallest stone dimension or 8" whichever is greatest. All rip-rap shall be underlain by geo-textile fabric. All rip-rap shall be entrenched such that the top of the rip-rap is to the line of the adjacent ground.

Where subsurface water movement or excavation below the water table may cause seeps, soil erosion, soil slippage, sloughing, craving or other earth movement, adequate subsurface drainage facilities and permanent surface stabilization measures shall be installed as necessary to prevent slope instability, soil erosion, and sedimentation.

The same end result of structural stability is required for an earth impoundment. The suitability of the in-place foundation soils must be analyzed; the embankment cross-section, soils, compaction, outlet structures, etc. must be engineered to prevent slope instability, piping, seepage, settlement, etc. This also applies to existing earth fills that will be subjected to an increase in the backwater elevation due to an alteration of the drainage structures or due to storm water diversions. Anti-seepage collars must be installed on all impoundment pipe outlets. On the interior surfaces of an impoundment, the permanent stabilization method, materials, plant surfaces, etc. must be carefully chosen to insure that the method is appropriate for the range of water level fluctuations and/or inundation duration and frequency of occurrence.

The existing surface cover types must also be analyzed and modified as necessary in areas that are not being disturbed but will be experiencing a change in water velocities, the range of water level fluctuations, and/or inundation duration and frequency of occurrence due to storm water diversions and/or alterations of drainage control structures. The State law requires that all drainage conveyances be designed to prevent erosive velocities, therefore, in the locations where the existing ground surface cover will be subjected to erosive water velocities as a result of this project, the use of energy dissipaters and velocity control structures will be required unless all affected surfaces protected as necessary to prevent long term erosion problems.

The plans must show detail drawings of the configuration and dimensions of all rip-rap culvert aprons, energy dissipater, spillways, and down drains. All rip-rap down drains and impoundment spillways must be engineered using the USDA "Rock Chute" design method or other appropriate engineered method.

Performance Guarantees:
Performance guarantees are required for most earth changes that exceed 1000 cubic yards (27,000 cubic feet) of earthwork. The project must be bonded for the full cost of the work required under the permit conditions. The performance guarantee may be in the form of a surety bond, cash bond or irrevocable letter of credit. If the project owner is a government agency, in lieu of a bond, an agreement may be entered into between the project owner and the Conservation District whereby the owner agrees to act on the bond on our behalf in the event that the contractor must be bonded to the owner for 100% of the permit requirements, i.e. the contract documents must incorporate all of the work as approved and required by this office.

Maintenance:
The State law requires that the soil erosion and sediment control plan include "a program proposal for the continued maintenance of all permanent soil erosion control facilities which remain after project completion, including the designation of their person responsible for the maintenance."

Easements:
Prior to issuing a permit, the applicant must obtain construction easements for all earth changes private properties that are not owned by the project owner.

Appeals:
The iron County Conservation District Board of Directors will be serving as the appeals board for Part 91, the Soil and Sedimentation Control Program. Any matters that you may have for them may be directed to the District Administrator at (906)875-3765.