Wetland Delineation and Watershed Analysis Report for Travel, Pin Oaks and Whitehill boundary sections of Petersburg National Battlefield (PETE)

Sharpe, Peter

The objective of this investigation was to respond to a request for regional assistance for a comprehensive delineation of wetland habitats subject to jurisdiction under Section 404 of the Clean Water Act and all wetlands subject to National Park Service (NPS) procedures for implementing Director’s Order #77–1: Wetland Protection within the Whitehill section of the Petersburg National Battlefield park boundary. A secondary objective was to provide the park with a basic watershed analysis for the Whitehill drainage area. This work utilized the U.S Army Corps of Engineers (USACE) Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Atlantic and Gulf Coastal Plain (Version 2.0) (November 2010) as the primary methodology for making wetland determinations in the field and was conducted during non-growing season conditions. One palustrine forested wetland encompassing 22.64 acres and one riverine wetland totaling 0.08 acres were identified and delineated from 8-10 August 2017 within the 27.52 acre study area (Fig. 1). The observed palustrine wetland habitat was classified as palustrine, forested, broad leaved deciduous, seasonally flooded, partly drained (PFO1Cd) habitat. The mapped riverine system was classified as a riverine, intermittent, streambed, mud system (R4SB5). Both of the identified and mapped wetlands meet the U.S. Army Corps of Engineers criteria and the Cowardin et al. (1979) definitions of wetland and waterway habitats. A combination of desktop watershed delineations using the USGS StreamStats software coupled with field observations of anthropogenic drainage features were used to make a general determination of the contributing watershed to the study area. Based on this analysis it appears that the 12 inch diameter reinforced concrete pipe owned by the City of Petersburg which serves as the primary means of conveying water out of the study area is insufficiently sized to pass the modeled 2-year peak urban flow.