Southeast Metro 115 kV Transmission Project

Purpose

The erosion control plan requirements described herein, shall apply to proposed transmission lines and substation additions. The purpose of these erosion control requirements shall be to prevent silting and muddying of lakes, ponds, wetlands, and any rivers or tributary streams of creeks which may lie in close proximity to the proposed facilities.

The specific erosion control features outlined in this document will be specified in the transmission line construction contract and on the site grading drawings for the proposed substation site development plans.

Performance Requirements

The erosion control plan requirements shall be performed and maintained during grading, topsoil placement, and turf establishment operations.

Earthwork shall not start until affected areas such as lakes, ponds, wetlands, rivers, and streams are protected by appropriate and effective erosion control devices.

Critical erosion control areas involving public waters or wetlands shall be expeditiously provided with complete final grading, topsoil placement, and turf establishment. At large site developments these operations shall be completed on a drainage area basis in order to provide permanent erosion control as soon as possible.

Temporary drainage control items specified herein, or on the grading drawings, which contribute to the control of erosion and sedimentation shall be provided.

This work shall be performed concurrently with earthwork, final grading, and turf establishment operations, or in cases involving relatively small site developments, this work shall be completed as soon as practical.

The amount of surface area exposing erodible soil at any time for relatively large site developments, shall be limited when temporary or permanent erosion control features are not in place and operative.

The Applicants shall establish and complete all permanent erosion control features required for the site development. All temporary features shall remain in place to the extent practical, until permanent erosion control features are effective.

The Applicants shall establish and complete, or rework erosion control items, to the extent necessary to correct conditions which develop during the sequence of work on the site. These efforts shall be maintained until permanent turf establishments, drainage facilities or controls incorporated into the grading drawings are complete and operative.

Erosion Control Features

The following erosion control features specified herein and on the site grading drawing shall be provided at the proposed site development.

Areas of exposed erodible soil in the coarse of earthwork operations shall be shaped to permit storm runoff with minimum erosion.

Temporary berms, slope drains, diversion mounds and sedimentation basins, as shown on the drawings, shall be required where possibilities for water pollution exist and permanent erosion controls are not completed or operative.

Silt fences shall be required to prevent sediment from entering wetlands or open water. One of the two following types may be used.

• Stacked bales of straw or hay may be used as described in the MN DOT Road Design Manual 8-5.0 19 dated January 31, 1982.

• Geotextiles supported by steel posts with securing pins at the base may be used. The geotextile material shall be a woven pervious plastic yarn and meet the requirements of ASTM D123, amended to date, and shall be selected to allow water transmission and retention of soils native to the site.

The Construction Process

Once the easement or land rights have been acquired and immediately prior to construction, Right-of-Way Representative(s), as a general rule, will contact the property owner and discuss the construction schedule.

During construction, the following may be required:

• Access routes

• Temporary removal or relocation of certain fences

• Installation of temporary (of permanent at land owners request) gates

• Early harvest of crops where possible

• Removal or relocation of equipment and livestock within the right-of-way.

When construction begins, you may witness movement of heavy vehicles, clearing of trees and other vegetation, and in the case of transmission lines, the delivery of poles and other materials, framing and setting of poles, and stringing of conductor wire.

Construction procedures will begin with the clearing of trees and brush along the new or existing route. If the project is replacing an existing line, where possible, the old line will be removed to facilitate the construction of the new line. The right-of-way will have an average width of 50 feet. If the existing facilities cannot be de-energized, they will be leaned during construction and removed at a later date.

When the right-of-way is prepared, a crew of surveyors will conduct a structure siting survey for each pole along the line route. Physical construction of the new line begins by auguring and digging a hole for the structure. At the same time, much of the foundation preparation work is underway, a crew transports poles, insulators, and insulator hardware from the staging or supply yards to the individual structure sites. When the materials have been delivered, the insulator and associated hardware are installed. After the pole has been assembled on the ground, a utility truck will be used to erect the structure.

The next step is the hauling and stringing of conductor and overhead ground wires. Several reels of wire are placed in the cradles, the wire is run through a series of sheaves which support and apply tension to the wire while it is being pulled into place by a winch. Once the wires are strung, they must be properly "sagged" to maintain pre-determined wire tension which meets state and federal rules and regulations.

The final construction operation is to "clip-in" the conductor wire. This involves removing the stringing sheaves and replacing them with clamps which attach and secure the conductors to the insulator strings. After the wire is clipped in, the construction operation will be essentially complete, with the possible removal of the old line and reclamation operations to follow.

Restoration and Clean Up

The Right-of-Way Representative will contact each property owner and/or tenant upon completion of construction. The purpose of this visit is to inspect the right-of-way work area to determine its condition. If damage is evident, it will be accurately measured and documented. In some cases the damage will also be recorded by photographs. Actual damage caused to crops, fences, etc., as a direct result of construction will be considered in calculating the amount of compensation. Accidental damage caused by unforeseen circumstances will be investigated by the Right-of-Way Representative as well.

The Right-of-Way Representative’s documented field data will be prepared into an itemized damage claim form and presented to the owner for consideration. A check for payment of damage will be issued. A statement of release will be requested from the owner and/or tenant where no damage resulted from construction.

In some instances utilities may engage an outside contractor to restore damaged property to as near as possible to its predisturbed condition. NSP’s reclamation goals are to control erosion, restore natural contours to the extent practical, restore drainage patterns, and revegetate the right-of-way.

Consultation with Agencies

The appropriate land office of county, state, and federal agencies with land use interests will be contacted. The information collected from these agencies will be utilized in guiding reclamation practices and possible land-use conversion decision. The reclamation efforts will be designed to establish diverse, stable, and self-sustaining vegetation communities. Reclamation will satisfy the following elements: (1) adequate cover (for soil protection), (2) adequate productivity (for domestic livestock and wildlife forage), and (3) suitable species composition (for livestock and wildlife forage and shelter for wildlife).

Landowner’s preference in reclamation will be followed as carefully as possible. When requested, the landowner will be provided guidance in selecting plant species and reclamation techniques, time of seeding, etc., for optimum establishment of vegetation.

Standard Mitigation Measures to Minimize Impacts to Vegetation Resources

The disturbance to vegetation will be minimized during construction by application of the Best Management Construction Practices. All disturbed areas will be reclaimed. Specific details regarding these activities are as follows:

1. Structures will be located and designed to conform with the terrain. Leveling and benching of the structure sites will the minimum necessary to allow structure assembly and erection.

2. Structures will be carefully located to span narrow bands of sensitive vegetative conditions.

3. Existing roads will be used for the construction of the line whenever possible. This will help to minimize impacts to surrounding vegetation communities. Except where the clearing of vegetation is required, all vegetation will be protected from damage by construction operations.

4. The clearing of vegetation from structure sites will be delayed until absolutely necessary, thereby reducing the time that bare soil is exposed. This will control erosion and minimize weedy plant opportunities

5. Special emphasis will be taken to minimize traffic over soils susceptible to wind and water erosion.

6. Reclamation should be conducted shortly after the construction is completed to eliminate opportunities for weedy species invasion, and will include regrading, discing, mulching, fertilization, and reseeding.

7. A native seed mix should be developed and used to reseed the disturbed areas after construction of the transmission line.

8. Soil compaction due to overland travel and structure development should be minimized. Construction activities will be curtailed, if necessary, to minimize damage to saturated soils. If compaction results, soils should be disced as soon as possible after construction is completed. If possible, site activities will occur when the ground is frozen.

9. Any erosion/reclamation problems will be corrected immediately upon discovery. The ROW will be inspected regularly both during and after construction to insure that problem erosion areas are identified and revegetated promptly.

Standard Mitigation Measures to Minimize Impacts to Wetland Resources

Mitigation measures are also applicable to construction activities involving wetlands. The disturbance to wetlands will be minimized during construction; and all disturbed areas will undergo reclamation. Specific details regarding these activities are as follows:

1. All open water (i.e. lakes, ponds, and artificial waterbodies), wetland, streams, and rivers will be avoided if possible or spanned.

2. Construction of the transmission line will be conducted during the winter months in wetland areas if possible. This would assure that soils are frozen and water levels will be lower than during the spring runoff.