NJ-NY ERFO FW WARI 2019-1 HYD Memo

Form FHWA-201
(Rev. 11-87)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

MINUTE - MEMO

Use this form in lieu of transmittal slips within Dept. of Trans. when message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA-121 for informal correspondence.

SUBJECT: NY ERFO WARI 2019-1(1) Scour Hydraulic Memo
TO

Gwendolyn
Riffle
Project
Manager
Canisha
Lyons
Highway
Design
Manager

MESSAGE/COMMENT

FROM/DATE

We have completed the scour analysis for the stream stabilization along the Winding Waters Trail within the Wallkill River National Wildlife Refuge in Warwick, New York. This memo has been revised to reflect changes to the scope and limits of work identified during the Plan-in-Hand site visit in midJuly 2025.

Isis RosadoVazquez
Hydraulics
Senior Technical
Specialist
Digitally signed by
The project scope includes streambank repair work at three locations. The ISIS Y ISIS Y ROSADOstreambank failures along the Winding Waters Trail (Sites 240 and Site 324) ROSADO- VAZQUEZ 2025.12.05
will be repaired using buried vegetated riprap revetment. At Site 3, an eroded VAZQUEZ Date: 14:33:12 -05'00'
bank at the outlet of a gully will be repaired using standard riprap revetment. All project sites are located within FEMA Zone AE mapped floodplains with THROUGH designated Base Flood Elevations (BFEs).
Wendy Hiciano
Hydraulics Team
Leader
Winding Waters 240 (41.295016700, -74.526450000)

WENDY MERCEDES

Winding Waters 324 (41.295733333, -74.525733333)

HICIANO

Digitally signed by WENDY

MERCEDES HICIANO

Date: 2025.12.05 14:36:38 -05'00'

Streambank failures along the Winding Waters Trail (Sites 240 and 324) will be repaired using stream-stabilization measures by realigning the trail and regrading the banks to create a flatter and more stable slopes suitable for installing buried vegetated riprap revetment as a scour countermeasure. Based on Chapter 7 of the PDDM, longitudinal embankments should be 12/05/2025
designed to withstand the estimated worst-case longitudinal scour up through the 100-year flood.
The hydrologic analysis was performed using the USGS Streamstats® online automated hydrologic module which automates drainage area delineation from digital terrain models and computes peak flow discharges following standard regional regression equations. In addition to the main channel (Wallkill River), two unnamed tributaries were also considered in our