WP0040203 - Laserfiche WebLink

Home Browse Search

Notification #1600-2018-0342-R3 Streambed Alteration Agreement October 28, 2019 Page 6 of 24 excavator or a clamshell bucket. Floodwall and Fill Placement Grading will occur along Dad's Point from Station 17+25 to 18+95, as well as Station 22+50 to 28+50, and would primarily be down the center of Dad's Point where existing groundcover consists of landscaped grass (Exhibit B). A single sheet pile floodwall will be built, and fill will be placed in additional areas to bring the entirety of Dad's Point up to a minimum elevation of 15.0 feet. To accommodate the new single sheet pile floodwall and fill placement, the existing landscaping and concrete pathway along the middle of Dad's Point will be removed. Most of the existing vegetation along the edges of Dad's Point will be preserved in place. A 1 -foot -wide trench will be excavated using a backhoe between Stations 13+50 and 30+13. Sheet piles will then be installed using a vibratory hammer and impact hammer, and a 2 -foot - wide concrete cap will be constructed on top of the single sheet pile floodwall where exposed. If flood wall installation occurs outside of the July 15 to November 30, in -water work window, installation will be done using a vibratory hammer. An impact hammer may be used for sheet pile driving only if the installation occurs during the in -water work window. The single sheet pile floodwall will be designed in accordance with USACE Engineering and Construction Bulletin Number 2014-18 (Design and Evaluation of I -Walls Including Sheet Pile Walls) and Engineering Circular Number 1110-2-6066 (Design of [-Walls). Dad's Point will be regraded following construction of the floodwall to cover both sides of the floodwall wherever possible, possibly requiring placement of fill material to form a 20 -foot -wide levee crown. Grading activities may require the temporary removal of existing concrete riprap along the banks of Dad's Point to accommodate construction equipment. This concrete riprap would be replaced following the completion of adjacent grading activities. After grading, an 8 -foot -wide all-purpose road and a 12 -foot -wide concrete paver tail will be constructed along the crown to provide access to the southern end of the fixed wall and gate structure. An abandoned 30 -inch cast iron pipe that runs through Dad's Point will be removed where feasible. Field engineering may be performed to evaluate proper abandonment of any pipe remnants that may need to be filled with a concrete plug. Habitat and Recreation Improvements Improvements on Dad's Point will be made to provide recreational opportunities, habitat value, and overall experience for visitors. As part of recreational development, other improvements will be made, such as invasive species vegetation removal, revegetation of banks with native riparian species, and replacement of landscaping removed during construction. Habitat value will be enhanced through the installation of bat boxes on Dad's Point to increase suitable habitat for native species, where appropriate. Fishing Access/Wildlife Viewing Platforms Two fishing and wildlife viewing platforms (36 feet wide and 12 feet deep) consistent with Americans with Disabilities Act accessibility standards will be constructed on the river side of the peninsula approximately 750 feet apart to provide optimum spaces for engaging in these activities. The platforms will be constructed by driving 24 -inch steel pipe piles with an impact hammer into the bank in a pattern extending out from the peninsula to support the ramp and