B08_11 - CHOH 241450 - Pre-Application Meeting Notes - FINAL.pdf

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04.15.2020\NPS CHOH 241450 - Pre-Application Meeting Notes - FINAL.docx

351 McLaws Circle

Suite 3

Williamsburg, VA 23185-5797

P 757.220.0500

Place: WebEx Meeting

Date: April 15, 2020 Notes Taken by: VHB, Inc.

Project #: CHOH 241450 Re: Paw Paw Tunnel – Mitigate Rock Fall Hazards

ATTENDEES

• Vik Desai, VHB

• Tim Davis, VHB

• Matt Radcliffe, MDE

• Paul Busam, MDE

• Jamie Larking, USACE

• Dan Tower, NPS-DSC

• Chris McKenna, NPS-DSC

• Joe Reed, NPS-CHOH

• Kevin Stanfield, NPS-CHOH

• Andrew Landsman, NPS-CHOH

Project Overview (Presented by Vik)

• Project Purpose: Rockfall remediation just north of the Paw Paw Tunnel. The purpose of the call is to discuss the permitting requirements so that the information can be passed along to the design/build contractors. Ultimately, the winning contractor will be required to file and obtain all necessary permits as a design/build project.

• As an overview, Vik explains that there are three (3) access route options listed below. Each option has their own physical and environmental constraints.

o 1 – Through the tunnel o 2 – Tunnel Hill Road/Trail via Malcom Rd o 3 – Go around to north side (~15 miles route)

Permitting Package Overview (Presented by Tim)

• NPS currently holds active permits that could potentially be modified for this work o The work on all previous authorizations is complete

MDE permit 17-NT-3192/201761187 June 23, 2017. Modification was effective April 1, 2019.

Expiration dates of June 23, 2022.

USACE permit NAB-2017-00457 o VHB has not quantified impacts yet, but they will be mostly temporary.

• USACE and MDE would like to see a separate permit for this work: will likely fall under a general permit.

Ref: CHOH 241450

April 16, 2020

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351 McLaws Circle

Suite 3

Access (Presented by Joe Reed, NPS)

• Staging Area: Primary construction staging area is anticipated to be at Paw Paw Campground Parking Lot adjacent to MD Route 51. Contractor may use clean material from off-site or break up larger material generated from rock scaling operations to expand parking area. Contractor may also expand entrance to parking lot as a beneficial use of the scaled material in order to improve access and mitigate the safety issues with the one lane entrance road to the park. These would be permanent features.

o Joe Reed states that additional processing of the spoil material (i.e. crushing) may be needed in order to use it. There is also a drainage pipe under Old Town Road (MD Route 51) that would need to be extended as well as modification to the guardrail along the shoulder of the roadway, which would require coordination with Maryland Department of Transportation (MDOT).

o According to the latest Flood Insurance Rate Map (FIRM), the entrance road and parking area at Paw

Paw Campground is within the 100-year floodplain. Paul states that NPS will need to demonstrate purpose and need, justify that there is no alternative outside of the floodplain for the spoil material to

go. Modelling is not necessarily needed if we maintain close to the same grade, but it would be considered a permanent impact.

• Construction Access Option One (Through Paw Paw Tunnel):

o The contractor will only be allowed to use the tunnel to transport heavy machinery to and from site on a limited basis (i.e. mobilization and demobilization), any frequent hauling of heavy loads would not be allowed.

o Extraction of spoil material through the tunnel presents concerns about vibrations, noxious fumes, and damage to the tunnel that prevent the construction contractor from using this as an option.

o The contractor will be required to haul all remaining material and spoils using one of the remaining access routes. Waterways will be avoided if possible, and if resources cannot be avoided, timber mats will be used to avoid impacts.

• Construction Access Option Two (Tunnel Hill Trail/Road): Joe described the potential use of Tunnel Hill

Road that crosses Green Ridge State Forest and returns back into NPS property. There are two culverts

(HDPE), and sensitive archaeological features as well as narrow areas with switchbacks.

o One potential use of the crushed spoil material would be to place on roadway as a beneficial use.

o Protection of existing culverts could be done by bridging over them with timber mats.

o Will require coordination with Green Ridge State Forest because that is where most of the trail is.

Mark Beale is the contact. Will trigger species reviews and additional review through the Department of Natural Resources (DNR).

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351 McLaws Circle

Suite 3 o Narrow spots and toe of slope would go out into the drainage channel – requiring USACE and MDE review if slope stabilization is needed.

o Cultural resources concerns include a dry-laid stone retaining wall, and a spoil pile from original construction of the canal.

o The current access road along the lower limb of the switchback nearest to the towpath is undercut and will require improvements/stabilization if used as a haul road.

• Construction Access Option Three (~15-mile route to access the site from the north):

o Would require approximately 1,700 feet of temporary disturbance in the canal (approx. 1000 feet in physical work zone and additional 700 feet between work zone and existing ramp); to scale and remove talus from the work area via transporting it through the canal prism up to the existing ramp on the towpath, and haul down the towpath past historic locks and a wasteweir for approximately 2-miles to an old spoil area used previously by NPS from the 1970’s.

NPS would need to improve the existing causeway across the canal at the old spoil area that facilitates traffic between the towpath and berm.

There would be a temporary stream (Twigg Hollow) crossing if the NPS gate into Green Ridge

State Park is used that leads to Outdoor Club Road.

The spoil area is within mapped 100-year floodplain.

Paul states hydraulic modeling will need to show there is no adverse impact to the floodplains attributable to any potentially placed fill.

Joe states that if NPS can’t put the spoil in the floodplain, the contractor will have to haul it off-site and dispose of it outside NPS lands in accordance with local, state, and federal regulation. Haul distance is a big driver for costs on the project. Hauling the material and disposing of it off-site is anticipated to have greater cost than disposal within NPS lands, which means less money is available to actually repair the rock slopes and boardwalk. The project is cost constrained already. We won’t be able to mitigate as much of the risk of existing rockfall hazards if we have to pay for off-site removal or extended trucking distances.

Tim asked how much material will be removed and how many truck-trips would it take to haul the material out. Vik stated that the spoil will be in the range of 8,000 to 9,000 CY. Assuming one truck can haul about 8 CY, it may take 1,000 to over 1,100 trips each way.

MDE will need NPS to look heavily at other alternatives, putting spoil in the floodplain is not usually considered to be in the public’s benefit. Need to prove if there are no other feasible alternatives for MDE to accept. Clearly, its not an option to leave the material in place. If fill in

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Suite 3 the floodplain cannot be avoided, then MDE would like to see a higher and smaller footprint for spoil piles to minimize the impact.

Joe asked MDE if there is an issue with the material being hauled off site? Does MDE need to know where the material is being deposited as part of the permit application materials? Paul stated that If contractor takes it off-site, MDE just needs to know that it’s not in a stream or floodplain. Deal with this as a generality “it will be disposed of in an upland area”. How much spoil material may trigger some E&S issues – but usually there is already authorization for that in the receiving areas.

Joe mentioned that the park was considering reconnecting a stream channel near the spoil pile to its original bed to prevent it spilling directly into the Canal. Currently the tributary dumps into the canal through a breach in the berm, the planform meanders, stream bed currently initiating headcuts, and contributes a large sediment load into the historic canal.

Preliminarily, MDE doesn’t see a problem with this (getting twice as much stream as far as length), but NPS would need to incorporate some stream restoration techniques. MDE would need to see specific details of what is being proposed. Need velocities and water quantities flowing downstream, etc. Generally, the idea is good. The stone culvert may be an issue for stormwater events reaching the stream due to it’s existing capacity and perceived runoff during a storm – which may be why it originally jumped the bank to flow into the Canal.

Waterways impacts would need to be considered in future submissions or development of this option.

Jamie asked about having a wetland delineation performed at the chosen spoil site. NPS stated that once a site is selected, a delineation will be done.

NPS will consult with Maryland Historical Trust (MHT) after more is known about the project. NPS has not contacted MHT yet, but previously coordinated with them about the 2017 – 2019 slope stabilization work.

Infilling existing locks may be required for this option to protect the walls of the historic locks, Infill could be temporary or permanent.

Permitting process could be drawn out with the locks because of Section 106, would look at these as “restorations”.

• USACE confirmed that the Maryland State Programmatic Permit #5 limits are 2,000 LF and 1 acre of wetlands. Above that amount, and the project gets elevated to an Individual Permit.

o The impact thresholds only apply to impact zones below OHWM. Stick to Category B if possible.

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Suite 3 o NPS will need to include the rerouted channel and the “waterfall area” within the cumulative impacts as well if they are altered by the project.

o NPS will need to identify sub-watersheds for 100-year floodplain analysis.

o Jamie stated that it takes 45-60 days for a General Permit from receipt of complete application. An

Individual Permit is 120 days with a public notice and public notice comment period (those periods included in the 120 days number).

o MDE and USACE encourage use of the second option (Tunnel Hill Road) – but understanding that there are several archaeological and access constraints.

• Additional Questions and Concerns o Tim asked about how to treat the rock material in the canal prism…uplands or wetlands? Will the delineation need to go around the existing rockslide since the rockslide is a natural event and it could be now the “normal circumstances”? Jamie stated not necessarily, but to rely on professional judgement.

o The agencies can use restoration as a way to streamline this in the permitting process.

o Joe stated that NPS has considered an option that the contractor could construct a cofferdam in the canal, just north of the tunnel portal, to exclude water from the work area and impound water in the canal/tunnel. This could potentially facilitate the contractor using barges and floating the spoils through the tunnel.

o Any in-canal work would need to consider measures to convey water during storms as well as long term function over time.

o Although schedule has not been determined, it is generally thought that once construction begins, expect 18 months to finish.

o NPS has finished the work under the existing permits and those permits can be closed.

o Joe asked the question about pushing some of the spoil underneath the boardwalk to support the boardwalk and protect the boardwalk from a future slide. Paul stated that from a waterways aspect, there is no issue, unless DNR has an issue with fisheries resources. This will count towards your water impact quantity. Both permanent and temporary impacts count towards the 1-acre threshold.

• Summary of discussion o Each of the construction access options presents its own constraints that will require the design build contractor to apply for a permit through USACE and MDE o New permits will need to be executed for both USACE and MDE

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Suite 3 o Areas of the spoils within the Park will need to be identified and wetland delineation will be required at each area. Floodplain related studies will also be required.

o If spoils are taken offsite, contractor will need to provide proof that they are being disposed of outside 100-yr floodplain.

o If requirements of the General Permit (GP) are met, it takes 45-60 days from receipt of complete application. An Individual Permit (IP) is required, 120 days will be required. IP process will include a public notice and public notice comment period (those periods included in the 120 days number).