DEP Project #: L-24441-24-A-N/L-24441-TF-B-N
Date: Fridday, 12-04-09 Time: 7:30-1:00 PM Report: 19
Observed by: Steve Roberge, PE Company/Agency: SJR Engineering Inc.
Weather Conditions: 40s, Sun
General Contractor: Reed & Reed Civil Site Contractor: Sargent
Clearing Contractor: DGD Trucking/JML Trucking & Excavating
Contacts onsite: Ray (Reed+Reed), Bob (Sargent), Tracy (Sargent), Dan
Date of Last Inspection: 11-30-09
Estimated # of days since last rainfall over ½”: 1 days ago, 1.2” rain event
Photographs taken: 15 see attachments
The purpose of the site visit was to determine and document the effectiveness of the erosion control program being implemented at the project site and to insure the methods being used are being maintained. A significant 1.2” rain event occurred on Thursday. The site walk noted no significant erosion events.
Sargent continues installing/maintaining erosion controls along the cleared/skidded sections of ROW and construction access from Tower 22 to Tower 8. The JML crew is responsible for maintaining Tower 8 to Tower 1 access as well as the North End access up the mountain. Many areas have been grubbed and covered with hay mulch, erosion control mix, rock fill, and stone check dams to minimize potential erosion on the ground surface. However, the cleared/skidded/stumped areas from towers 16 to 10 and 8 to 1 have yet to receive any mulch cover on disturbed soil surfaces. The Contractor was advised to make this item the highest work priority as mulching is not permitted on snow/ice surfaces. Any snow/ice event must be removed to less than 1” thickness prior to mulching according to construction plan note 8 and Maine BMP’s. Working on this item over the weekend was suggested due to the late date and amount of work remaining.
Maine Drilling and Blasting is operating full time at the site. Daily blasts (noonish) have occurred making rock available for road construction and slope stabilization. They are operating in the Tower 22 and Tower 17 areas of the Mine Notch Road.
Sargent has grubbed the main construction access road and the Mine Notch Road from tower 16 to Tower 22. Blasted rock has been used to construct the crane access road from Tower 22 to 14+00 and to approximately station 30+00 of the Mine Notch Road. The construction access road has all upslope ditching with riprap and some permanent culverts installed. The Contractor re-evaluated the slope stability along the backslope of Mine Notch Road station 12+00. Due to the rain event, it was evident to them additional stabilization was necessary. They are installing riprap along the slope over the erosion control blanket for the full length of the slope. This is an excellent call to minimize the potential for a slope slide in this area.
The following items were inspected:
1. Silt Fencing: The silt fencing work continues to be a work in progress along the crane access road and tower pads. I did note a section of silt fence that needs to be installed near the rear of tower 16 and the crane access road to tower 17 where blasting is occurring.
2. Stabilized Entrance: The contractor has stone at the entrance to the project to minimize any tracking of soils. They have also installed additional crushed stone at the ends to bridges to minimize tracking of material onto the stream bridges and therefore into the stream.
3. Stockpile Area: Sand stockpiles have been created and surrounded with silt fence to capture any soils that may leave the pile. Other areas of stockpiles and final grading areas need a mulch covering as winter conditions are now enforceable.
4. Mulching: Several areas have received an adequate covering of hay mulch to limit the exposure of the disturbed soil surface along what would be considered the active work areas. Sargent and JML Construction continue covering sections of exposed soils with a heavy hay mulch application for winter shutdown. Sargent has completed mulching road/towers 8 through 10 as of this site visit. This is an on-going work activity, but better progress is essential at this time of year. Mulch is required during winter conditions for stockpiles that are left in place longer than 7 days or prior to a rain event. Mulch is required on all disturbed soils prior to a snow event. Snow/ice must be removed to less than 1” thick prior to mulch stabilization. Significant un-mulched areas remain along the ROW from towers 17 through 1. The Contractor was advised to make this a high work priority and to work over the weekend due to the late date and amount of remaining work to be accomplished.
5. Erosion Control Mix: Many of the water bar outlets have erosion control mix or crushed stone installed to collect sediment. The erosion control mix at the outlet end of the water bars again captured significant amounts of sediment in the grubbed areas of the crane access road. These need to be cleaned again and prepared for the next storm event predicted for Saturday. Sargent has completed making erosion control mix with their grubbing/stumping operations for use this Fall/Winter. The Met Tower access road will have outlet protection such as the erosion control mix or stone check dams depending on the flow of water across the bars once the road freezes in.
6. Dust Control: Not needed at this time.
7. Hay Bales: Hay bales have been installed in conjunction with silt fence in the areas near resources and along the downslope side of construction for the access road. This meets the requirements for double barriers protecting resources during winter conditions. Most of the hay bales are better used for mulching purposes.
8. Stone Check Dam: The existing gravel access road has water bars with check dams being located in the ditch lines. The ditching along the upslope side of construction has stone check dams. The Contractor has all ditching lined with riprap along the construction access road. The stone check dams along station 28+00 of the construction access road have been cleaned and maintained.
9. Culverts/Riprap: IF&W has not permitted an extension to the time window for installing culverts within streams. Other culverts have been installed within drainage paths as called out on the plans. The culverts have inlet/outlet protection.
10. Level Spreader: Level spreaders are being constructed in several locations along the construction access road.
11. Water Bars: The gravel access road has erosion control devices such as drivable water bars with stabilized outlets (stone and/or erosion control mix check dams) being located along the steeper portions of the entrance road. Many additional water bars are located in the grubbed construction access road to allow upslope water easy passage across disturbed soils. The water bars have erosion control mix installed along the outlet end of the bars. These worked very well as significant amounts of sediment have been trapped within the dams with no visible sediment beyond the dams.
The Met Tower access road has been closed out (restored) for the full length of the road. The Contractor has installed many water bar diversions. The bars do not have any outlet protection such as rock check dams or erosion control mix installed at the end of the bars. The sediment in the existing ditch turnouts has not been cleaned. The Contractor will perform these tasks once the road freezes in to limit damage to the existing restored areas. Review of this road this week, revealed the restoration efforts are limiting erosion and sedimentation from occurring.
12. Catch Basins/Stormdrain system: Some culverts are being installed in drainage swales along the ROW (not streams) to pass the upslope watershed through the access road. The culvert discharge points are being protected with a stone riprap inlet and outlet protection pad. These discharge points should flow to undisturbed stabilized surfaces along the edge of ROW or natural undisturbed ground surface.
13. Ditches/Swales: The gravel access road is being managed with proper erosion control devices including check dams being located in the ditch lines. The Contractor continues lining ditch bottoms with geotect fabric and riprap stone along the Mine Notch Road. The riprap ditching along the upslope side of the construction access road has been completed.
14. Groundwater seeps/Hidden Channels: The Contractor should continue to review locations where seeps are visible. These should be marked for future considerations with regard to how the access roads are constructed (rock sandwich).
15. Cut/Fill Slope Protection: The Contractor has hay mulched disturbed soils throughout much of the active working project. Skidder trails have brush and/or corduroy placement in locations of steep slopes to minimize erosion at other locations. The closed-out skidder trails 1+2 have been seeded and have an application of hay mulch cover to limit any erosion potential from this disturbed surface. The Contractor has devised a system of water bars, bypass culverts/ditches, and sediment containment areas to limit erosion and sedimentation along disturbed soils. Construction of the Mine Notch Road from station 30+00 to tower 22 has a rock base. The Construction access road is completed with the exception of a few permanent culverts and an additional application of hay mulching.
16. Vegetative Cover: Not applicable at this time.
17. Stream/Wetland Crossings: Bridging streams and matting wetlands are the only acceptable means for crossing at this time. IF&W has not extended the stream culvert placement window for this project. All in-stream work must be conducted between July 15 and September 30.
18. Spill Prevention: No evidence of any spills has been noted during this visit.
19. Winter Construction: The Contractor has been under winter construction requirements since November 1, 2009. The Contractor has reviewed the winter condition requirements with his crew particularly with regard to double silt barriers in environmentally sensitive areas and additional hay mulching timelines/application rates and is implementing the plan as required. That stated, I offer the following information: Mulch is required during winter conditions for stockpiles that are left in place longer than 7 days or prior to a rain event. Mulch is required on all disturbed soils prior to a snow event. Snow/ice must be removed to less than 1” thick prior to mulch stabilization. Significant un-mulched areas remain along the ROW from towers 17 through 1. The Contractor was advised to make this a high work priority and to work over the weekend due to the late date and amount of remaining work to be accomplished.
20. General nature of project: The project erosion control activities are current with the active work operations. Skidder trails 1+2 and the existing Met tower access road are restored and closed to traffic. The north access skidder trail has been partially restored, but no work was performed on the road due to yesterday’s rain event (good call again). Time is becoming limited to continue operations without having to deal with snow/cold temperatures and shortened daylight hours.
21. Areas currently under construction/disturbance: Clearing activities and bridge construction over streams have been performed from station 1+00 along the construction access road to the Tower pads 16 through 22 including crane access road. The clearing crew has cut/skidded the main construction access road and Mine Notch Road from tower 1 to tower 22 and is finished until frozen ground conditions are present. The ROW has been cut along the crane access road full length.
22. Estimate total area under construction/disturbance: Station 1+00 through 80+00 of the construction access road building has completed construction. Grubbing has occurred from tower 16 to tower 22 locations with the rock fill being placed along the road and towers 18 through 22 and to station 30+00 of the Mine Notch Road. Clearing/skidding operations are completed along the crane access path from one end of the project to the other. The Contractor has cut/skid/decked trees along the ridgeline from Tower 1 through Tower 12 and will bring them down the mountain along the crane road as it becomes available. The contractor is mulching the skidder trails along the ridgeline.
23. Comments: The erosion control program is effective and is being implemented as needed and necessary to control erosion during the construction of the project.