B09_Attachment_8_-_Amendment_1_Enclosure_1_MOD_2_0001.pdf
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- Solicitation number
- 140P3021Q0046
About this file
This document provides an analysis of woody debris accumulation and tree management needs at multiple aqueduct structures within Chesapeake and Ohio Canal National Historical Park. The analyses identify full and partial obstructions at aqueduct structures including logjams, debris deltas, submerged debris, and invasive vegetation. Recommendations include removing targeted trees and debris, hauling all wood chips, cutting stumps flush with the ground, and following ANSI Z133 safety standards. The related federal contract opportunity is for woody debris management services along the aqueduct structures within the park. The solicitation was issued by the National Park Service for contract number 140P3021Q0046 to address the accumulated debris and complete the recommended tree removal and debris clearing activities analyzed within the attached document.
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Enclosure 1: Aqueduct Debris Overview UPDATED BY JASON GILLIS 19 July 2021
Post Site Visit Amendment
Debris Analysis: Seneca Aqueduct 1 of 3
Boat ramp
Debris Analysis: Seneca Aqueduct 2 of 2
OBSERVATION: Full obstruction just below the waterline creating logjam.
Partial access constriction for watercraft accessing the Potomac River.
Comprehensive debris field “delta” developing against jam with adjacent shoreline accumulation w/ potential for rapid expansion. Invasive vegetation on stone structure.
Debris Analysis: Seneca Aqueduct 1 of 3 (Amendment Addition)
Target Tree to be RemovedAqueduct
Remove Tree and all debris from park. Haul all wood chips. Cut stump flush 2-3 ft above grade. Leave 15-20 Ft habitat spar (cut flush across the top).
Aqueduct Analysis: Monocacy Aqueduct 1 of 3
Aqueduct Analysis: Monocacy Aqueduct 2 of 3 Maryland 28 Bridge Upstream Debris Field (1.70 Miles)
OBSERVATION: Large upstream debris field accumulated at MD DOH HWY 28 bridge.
Highwater has high probability of moving the debris field downstream to the partially obstructed aqueduct barrels. THIS IS NOT PART OF THE
WORK REQUIREMENT, BUT SERVES TO INFORM
THE CONTRACTOR OF NEAR VICINITY DEBRIS IN
ORDER TO INFORM ANNALYSIS OF
ACCUMULATION POTENTIAL AT THE MONOCACY
AQUEDUCT.
Aqueduct Analysis: Monocacy Aqueduct 3 of 3
OBSERVATION: Developing logjam and delta effect with broad submerged obstruction (tip of iceburg comparison). Potential for rapid expansion during high water events exacerbated by the proximity of MD 28 HWY bridge debris field.
Aqueduct Analysis: Catoctin Aqueduct 1 of 2
Access Point: Must cross CSX tracks off Lander Rd.
Aqueduct Analysis: Catoctin Aqueduct 2 of 2
OBSERVATION: Two of three barrels have complete obstruction diverting all hydrological action through the partially obstructed center barrel.. Accumulation of subsurface debris field and biomass.
Aqueduct Analysis: Catoctin Tree Management 1 of 8
Remove Tree and all debris from park.
Haul all wood chips Grind stump to a minimum depth of 8 inches.
Safety Standard: ANSI Z133 (most current)
Aqueduct Analysis: Catoctin Tree Management 2 of 8 (Amended Debris Requirement)
Remove Tree and all debris from park.
Haul all wood chips. Cut stump flush 2-3 ft above grade.
Safety Standard: ANSI Z133 (most current)
Major leader facing away from towpath may be felled “whole” and left in place. The contractor shall make every effort to mitigate damage to surrounding trees during the performance of the work.
Damage shall be mitigated by the contractor at no additional charge to the government through the reasonable application of arboricultural techniques in accordance with industry standards and best practices. The contractor is not authorized to fell trees not contained within the work specifications.
The contractor may remove necessary brush and ground shrubbery around the base of trees in order to facilitate safe work performance in accordance with ANSI Z133 standards. The leader shall be cut, so as to lay flat, and leave a natural aesthetic appearance.
Aqueduct Analysis: Catoctin Tree Management 3 of 8
Haul all wood chips. Cut stump flush 2-3 ft above grade.
Aqueduct Analysis: Catoctin Tree Management 4 of 8
Haul all wood chips. Cut stump flush 2-3
Aqueduct Analysis: Catoctin Tree Management 5 of 8
Haul all wood chips. Cut stump flush 2-3
Aqueduct Analysis: Catoctin Tree Management 6 of 8
Haul all wood chips. Cut stump flush 2-3
Aqueduct Analysis: Catoctin Tree Management 7 of 8
Haul all wood chips. Cut stump flush 2-3
Aqueduct Analysis: Catoctin Tree Management 8 of 8
Haul all wood chips. Cut stump flush 2-3
OPTION Aqueduct Analysis: Cononcocheague Aqueduct 1 of 2
Aqueduct Analysis: Cononcocheague Aqueduct 2 of 2
OBSERVATION: There are submerged pieces of the aqueduct structure that appear to be supporting the center debris field. There are multiple pieces of large submerged wood and bank accumulation.
Large piece of debris on Potomac side of structure.
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