REQUEST FOR PROPOSALS
Restoration Feasibility Study
and Hydrologic Analysis Of the
Topanga Lagoon and Topanga
What kind of lagoon and watershed enhancement/restoration design will create a self sustaining lagoon that will improve water quality, assess and minimize flood hazard, restore habitat for steelhead trout and tidewater gobies, and maintain recreational opportunities, without changing the surf break?The Resource Conservation District of the Santa Monica Mountains, under a grant from the Coastal Conservancy Southern California Wetlands Recovery Project is requesting proposals to prepare a comprehensive feasibility study of the potential for restoring the resources of the Topanga Lagoon and Topanga Creek Watershed. The purpose of this feasibility analysis is to identify and verify the physical characteristics of the existing creek and lagoon, and evaluate several possible restoration alternatives. The Feasibility Study must also outline a phased approach, including the necessary scope of work and budget to produce a sustainable lagoon/watershed restoration plan that can be implemented. The development and implementation of this restoration plan would be a subsequent, separately funded effort.
Many of the elements that would be integrated into the Feasibility Study have been completed or in progress. These include: water movement, water quality, biological resources, erosion and sediment delivery, as well as maps of the present and historic creek channel configurations. The work plan and results of these studies are available through the RCDSMM and/or online. (See references)
The hydrologic analysis needed for the Feasibility Study, however, has not yet been accomplished and is a major part of this RFP. Use of models that can evaluate both continuous storm events and more normal low flow conditions is expected. This information will allow planners to assess the natural and anthropogenic impacts in the watershed to determine the feasibility and potential design constraints impacting a restoration of the historic lagoon, which previously covered a much larger area.
Water quantity under a variety of conditions plays a major role in defining creek and lagoon configurations. A clear understanding of how these parameters interact with other physical processes in the watershed is necessary prior to designing a potential restoration plan. The restoration of Malibu Lagoon failed to incorporate watershed wide constraints, and as a result has experienced consistent problems, which we hope to avoid in Topanga. By contrast, the Carpenteria Marsh - Ash Street Restoration conducted a more thorough evaluation of physical constraints which informed the design process and resulted in a functional system. Therefore, the purpose of this Feasibility Study is to identify and integrate the various components of the creek/lagoon system and develop a sustainable, functional design plan. (See references for additional information.)
Since 1990, residents of the Topanga Watershed have been studying the Los Angeles County hydrologic analysis in light of its impacts on designating floodways and effecting the historic properties along Topanga Creek in the upper watershed. Their work led to the development of the Topanga Creek Watershed Management Study, which identified inconsistencies in the County analysis and the need to verify the County results. The Topanga Watershed Committee was convened in 1998 to provide a forum for community education and discussion of voluntary actions residents could undertake to reduce flood risks, reduce downstream impacts from new development, develop more environmentally sensitive streambank protection measures, retain drainage, reduce erosion and sedimentation, improve water quality and holistically attempt to become better stewards of the watershed. A number of research projects providing baseline information about the watershed are either on-going or completed. (See references for additional information.)
Concurrently, the Santa Monica Bay Restoration Project, CA Department of Parks and Recreation, the Santa Monica Mountains Conservancy and the Santa Monica Mountains National Recreation Area identified restoration of the historic lagoon as a high priority to help improve water quality at Topanga Beach, increase access for endangered steelhead trout, and enhance habitat for endangered tidewater gobies. The Los Angeles County Department of Beaches and Harbors has expressed a willingness to consider restoration possibilities for the area it oversees on the south side of Pacific Coast Highway. The LA Athletic Club property to the north of Pacific Coast Highway is under option for sale as parkland, and if purchased, could provide additional restoration potential.
In Spring 2000, adult steelhead were once again found residing in Topanga Creek. Improving water quality at Topanga Beach has become increasingly important and a year long study of water quality indicated that the upper watershed is contributing very little, if any, to the problems with high coliform counts at Topanga Beach. Funding for the Lagoon Restoration Feasibility Study became available from the Coastal Conservancy and the Santa Monica Bay Restoration Project. It is now time to move forward.
Scope of Work
The consultant will perform the following tasks to help achieve the Project Objective.
An integrated, comprehensive watershed and lagoon analysis is required in order to evaluate restoration possibilities within the context of existing watershed conditions. Data from on-going research, existing present, historical and digital resources are available. The Consultant will perform any additional hydrologic analysis required to determine the feasibility of lagoon and watershed restoration. Models will be selected that characterize continuous (potentially catastrophic) storm events, as well as calculate more common low flow conditions pertinent to the enhancement of the lagoon.
Examples of potential models include: HEC-2 and HECRAS analysis (available from Los Angeles County Dept. of Public Works), Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) developed by EPA; Agriculture Nonpoint Source Model (AnnAGNPS) developed by NRCS; Stormwater Management Model (SWMM) from EPA; Hydrologic Simulation Program Fortran (HSPF) from EPA; Storage, Treatment, Overflow, Runoff Model (STORM) developed by the ACE Hydrologic Engineering Center and.
Discuss the hydrological characteristics of the lagoon/watershed system and how these might change under each condition. Discuss tidal circulation potentials and how these designs might reduce flood hazard. Evaluate the role of the PCH bridge, as well as the possibility of lengthening the PCH bridge and how this could improve lagoon function.
The hydrological analysis may include, but not be limited to, the following components:
Pertinent references, previous and on-going research results, modeling parameters, and additional background information will be available for review on the web via the Topanga Watershed Committee site found at www.TopangaOnline.com. Additional materials are available by appointment at the RCDSMM, Topnaga, CA.
The Resource Conservation District of the Santa Monica Mountains has $55,000 to complete the tasks described above. The scope of work, methodology, or the scale of the project is somewhat negotiable; however, the maximum funding level is not negotiable.
Proposals of no more than 10 pages should contain the following items:
6 Copies of Additional information required includes (no page limit):
Proposals must bear the signature of a principal authorized to enter into a contract.
12 copies of the initial proposal must be received by the Resource Conservation District of the Santa Monica Mountains on or before January 15, 2001, to be considered. Send proposals to:
The Resource Conservation District of the Santa Monica Mountains
122 N. Topanga Canyon Blvd.
Topanga, CA 90290
Attn: Rosi Dagit
The Resource Conservation District of the Santa Monica Mountains, in consultation with the Coastal Conservancy, and the Technical and Landowners Advisory Committee will select the consultant. The Selection Committee will meet in early February 20001.
Only the most qualified applicants will be interviewed, but all firms or teams that submitted proposals will be notified of their status by the RCDSMM. The basis of the selection will include relevant experience in watershed analysis and integrated biological/hydrological lagoon design, project understanding, and cost-effectiveness.