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® 1.0 INTRODUCTION This report details the design procedure and hydraulic analytical methodologies utilized in the development of the North Branch of the South Fork of Littlejohns Creek(SFLJC)channel relocation project.The relocation project involves moving a 7,600-foot reach of SFLFC to the north and east of its present alignment.The creek is being moved to accommodate the expansion of the Austin Road Landfill.The existing creek has very little intact riparian habitat.Riparian vegetation is restricted to a very thin strip along the water's edge. Only ruderal and widely scattered riparian trees occur along the channel.The County Flood Control District routinely removes woody vegetation in this area.The channel does not have significant fish or aquatic wildlife. No plant or animal species listed as threatened or endangered are known to occur in the existing creek reach. Based on a wetlands delineation completed by Jones and Stokes in 1996,the existing creek channel to be, relocated has approximately 2.04 acres of open water habitat and 0.859 acres of adjacent wetlands.This project has been formally reviewed under CEQA and has been permitted by the U.S. Army Corps of Engineers(USCOE). As a condition of that permit the relocation project will create at a minimum 2.97 acres of water of the United States and 39.4 acres of total riparian habitat.This permit application and documentation is provided as an appendix to this report.The project applicant will be required to monitor the project for a minimum of five years and ensure that compensation objectives are met. The following report outlines the design procedure utilized to ensure that the constructed project meets the conditions of the USCOE permit. 2.0 DESIGN GOALS AND OBJECTIVES The goals and objectives of the relocation project can be divided into three general categories: (1) provide riparian habitat restoration/creation to mitigate the filling a portion of the North Branch of the South Fork Littlejohn's Creek from the expansion of the Austin Road Landfill; (2) provide adequate flood control in the realigned section of the creek;and(3)provide a stable channel design that meets or exceeds the functions and values of the existing creek. 2.1 Habitat Recreation The proposed mitigation concept is too create a channel realignment that recreates the function and habitat value of a natural creek system in this region.The concept is to create a riparian zone that has an appropriate mix of vegetation types and functions naturally with little maintenance and intervention. The long-term goals for management of a mixed deciduous riparian forest are to create a natural, self-sustaining ecosystem that provides high quality aquatic and terrestrial habitat, with minimum maintenance requirements, while at the same time meeting flood management objectives. Questa Engineering Corporation ( 99279MR/April t, 2000