ARCHIVED REPORTS_1996_2 - Laserfiche WebLink

Home Browse Search

A levels, the realigned channel is expected to have 2.09 acres of open -water habitat and 0.88 acre of streamside wetlands, totaling 2.97 acres of waters of the United States; therefore, the long-term replacement ratio for waters of the United States is 1.1:1. This plan assumes that the design of the proposed creek channel mitigation also addresses San Joaquin County flood -control needs for the proposed landfill expansion. This wetland mitigation plan is conceptual, providing guidelines for creek restoration and plant revegetation along realigned portions of Littlejohn Creek and, therefore, is not intended for use as a construction document. Design -implementation construction plans and specifications should be prepared by a qualified restoration specialist with proven experience in similar projects in both scope and magnitude. e Conceptual Mitigation Plan Features To meet the goals and objectives for the proposed creek realignment, the design program incorporates three primary concepts: creating high -terrace riparian habitat on the floodplain, maintaining the flood -control function of the existing creek, and incorporating special requirements of governing agencies as outlined below. The proposed conceptual master plan drawing is included as Figure 3-2. Riparian Habitat Creation r The primary mitigation• { • create a 200-fbot-wide{••• , ru enhanced riparian habitat value over that of the existing creek. The existing creek is a 46-foot-wi trapezoidal channel with minimal habitat value. No riparian habitat is present because the vegetati is cleared by County flood -control crews to maintain channel flows during flood events um pers. comm.). the proposed floodplain habitat should be able to sustain itself in perpetuity. The proposed riparian habitat is divided into two ecological planting zones (Figures 3-3 3-4). In the higher floodplain elevations, oak woodland habitat will be created by planting native trees and native shrubs common to oak woodland (Table 3-1). In the lower floodplain elevation cononwood-willow riparian woodland will be created by planting Fremont cottonwood, nati willows, and native vines (Table 3-1). Prior to planting the woody vegetation, an understory of nati grasses and forbs will be established on the floodplain. The total area of riparian habitat to be creat is 39.4 acres. I Although the creek will still exist in the context of an operating landfill, the mitigation plan ® has added features to maintain habitat integrity and buffer that habitat from the landfill operations. The existing channel has dirt roads above the floodplain and immediately adjacent to the both sides of the channel for access during channel maintenance activities (Figure 24). The realigned creek will have roads similar in character but placed outside a much broader floodplain (Figures 3-3 and 3-4). Wetland Mitigation and Monitoring Plan for the Chapter 3. Wetland Mitigation and Monitoring Plan Austin Road landfill Expansion, U. S. Arm Corps of Engineers File 199400974 3-2 April S. 1996 ' Cin• of Stockton