The Newport Bay Watershed 905(b) Reconnaissance Study was conducted by the Corps of Engineers to review and assess past and current activities and trends within the watershed, and to identify opportunities for addressing river management investigated hydrology, hydraulics, flooding, river geornorphology, erosion, sedimentation, land use, geology, soils, water quality, groundwater, vegetation, endangered species, and cultural resources. The study identified opportunities for the development of an integrated watershed management plan (the PLAN) comprising by local, state, and federal agencies.

The Reconnaissance Study also identified opportunities for multiple-use projects within the watershed that could become critical structural elements of the PLAN, and would provide environmental restoration and water quality benefits associated with watershed streams and the Bay.


2.2 Other Watershed Study Efforts

"Serrano Creek Watershed Study", by the City of Lake Forest provides a general creek restoration plan to address severe channel erosion.

"San Diego Creek Watershed Enhancement Plan", EPA wetlands grant to the California Coastal Conservancy, estimated 1998-1999. The purpose is to develop a comprehensive watershed enhancement plan, especially for the lower creek, which addresses sedimentation, water quality problems, habitat restoration, and recreation. The focus of the plan will be on developing and recommending specific actions to enhance the creek and its resources.

"Upper Newport Bay - San Diego Creek Water Quality Planning Initiative", EPA/SWRCB 205j Grant, September estimated 1998-1999. The purpose is to support watershed enhancement actions by creating and maintaining a central repository of watershed information, conducting watershed studies, implementing an Evaluation Monitoring Program, and establishing a stakeholder group to facilitate watershed enhancement actions. As part of this report, Orange County has prepared an annotated bibliography of available information and has a central information repository with over 280 documents at the University of California - Irvine Library. This is a key resource in determining what data is already available.

"Upper Newport Bay Water Quality Enhancement Project", EPA/SWRCB 319 Grant, 1998 - 2000. The purpose is to reduce or eliminate vegetative and urban trash debris in the watershed and thereby reduce or eliminate aquatic life toxicity from these sources.

"Total Maximum Daily Loads (TMDL's) for Sediments, Nutrients, and Toxics and Pathogens for the Upper Newport Bay - San Diego Creek Watershed", EPA 1998. The purpose is to reduce or eliminate water quality problems in the creek and Bay and to protect the beneficial uses of these receiving.

"Natural Community Conservation Plan & Habitat Conservation Plan, NCCP/HCP, joint programmatic EIR/EIS, and implementation agreement", Orange County Environmental Management Agency (now OCPFRD), 1996.

The Corps - Los Angeles District is currently developing a Scope of Work for a Special Area Management Plan (SAMP) for aquatic and riparian resources in Orange County. The work will build on the past accomplishments of the NCCP and previous planning efforts.

Watershed goals previously identified by the watershed management committee are also expected to be partially or wholly addressed through the Corps feasibility study process. They include:

• Reducing sedimentation and erosion
• Improving water quality
• Assuring flood protection
• Enhancing terrestrial and aquatic habitat
• Protecting sensitive species
• Improving the quality of life through education, recreation and aesthetic opportunities.

The general objectives and study products of the watershed management plan are:

a) A comprehensive update of hydrologic, hydraulic, and sediment (yield and transport) models for a range of flow rates for existing conditions and future conditions within the San Diego Creek watershed.

b) A comprehensive programmatic environmental document to assist in future watershed management. This includes identification of the environmental resources (key species and habitat types) that should be restored, enhanced or sustained to insure a well-functioning watershed supporting a wide diversity of plants and animal species.

c) Investigation of site-specific environmental restoration, sediment control, and erosion control opportunities within the Newport Bay watershed. Prioritize alternatives in the event that finding is not fully available.

d) Evaluation of ground water and surface water interactions and identification of the relationship to environmental conditions in Newport Bay watershed and the Bay. Identify the water quality parameters, and actions necessary to preserve existing natural resources and enhance or sustain the diversity and quality of species and habitat types essential to a healthy, well-functioning watershed.

e) Identification of actions and programs that can be implemented by Federal, state and local agencies that can help fund or implement solutions to water quality problems within the context of continued development of the watershed.

f) Establishment of a website and periodical newsletter for information regarding watershed and bay activities.

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3.2 Study Product

Section VI of the PSP describes the studies that define the existing conditions of the watershed, and studies necessary to formulate opportunities for improving watershed management and restoration measures. The organization of the PSP is consistent with the requirements of the Corps, listing study activities under their "code of accounts" for the various study activities. These accounts include:

The watershed study will generate key technical data, improving the knowledge base necessary for resource managers to make informed watershed investment decisions and identifying specific opportunities (restoration projects, regulatory modifications, educational plans) to improve watershed health. Development of the following information will be pursued:

1. A comprehensive update of hydrologic, hydraulic, and sediment (yield and transport) models for a range of flow rates for existing conditions and future conditions within the Newport Bay watershed

• Existing conditions will include the recently installed flood control or drainage facilities. For the future condition, the modeling will include proposed land use changes, any additional flood control or sediment control facilities, and the effects on the delivery of sediment to Newport Bay.
• Operations and maintenance (O&M) of sediment control facilities will be investigated through the use of the models to see if there are opportunities to improve sediment trapping abilities within the watershed through modification of O&M activities (i.e. a non-structural approach).
• Potential environmental restoration sites will be investigated at several sites within the watershed. Multi-use alternatives will be considered to maximize the benefits for the greatest number of stakeholders. For example, some of the sites may also provide sediment control benefits in addition to restoration. Those potential benefits will also be investigated using the models.
• Any potential modification of sediment delivery to the Bay and the effects on the Bay will be documented. It is assumed that improved sediment trapping would only result in changes to the frequency of O&M activities within the Bay for the mid-Bay basin(s) being investigated as part of the ongoing Newport Bay feasibility study.
  

The hydrologic, hydraulic, and sediment yield and transport models (generated under Subaccounts 6.9.A - Hydrology, 9.B - Hydraulics, and 9.C - Sedimentation) will benefit the ongoing TMDL process by generating updated baseline data that will allow for a more accurate assessment of the sediment and water quality related problems. The models will also provide a detailed technical basis for the design and evaluation of multi-use restoration sites for reduction of sediment and nutrients. The provisions for monitoring and maintenance under Subaccount 6.9C (Sedimentation) include a number of the program elements proposed by Orange County for compliance with the TMDL's.

2. Assessment of surface water quality as it affects environmental needs and recreational users. Data regarding temperature, dissolved oxygen, nutrients, depth, water movement criteria, sediment loading and other components of water quality within the watershed and Bay will be collected and analyzed to determine what constituents are constraining to environmental resources and recreational activities. The water quality data collected under Subaccount 6.5 - Environmental Studies, will be used in development of cost effective, upper watershed (and bay) treatment measures that benefit the TMDL process by controlling excessive sediment, nutrients, pathogens and toxic substances on a regional basis. The measures will be combined with environmental restoration projects where feasible.

3. Evaluation of ground water and surface water interaction and the relationship to environmental conditions in the Bay. Study groundwater and surface water interactions, contaminant issues, feasibility of groundwater dilution and other issues. Determine methods to improve quality of inflow and in-situ water. The collected data under Subaccount 6.9.D - Groundwater Studies can be used to assess the groundwater contribution of nutrients, toxics, and pathogens to the Bay, and thus benefits the TMDL process. Groundwater draining to the surface is also a potential water source for habitat restoration projects.

4. Evaluation of riparian habitat. Conduct landscape scale biologic evaluation to characterize the existing riparian habitat along the major streams within the watershed, and determine the locations of particularly high habitat value and diversity of habitat types. Study riparian corridor needs. Study relationship with existing channel network. Determine suitability of existing surface water for habitat, wildlife and aquatic species. Identify opportunities for in-channel restoration that is compatible with flood control objectives. The habitat data generated under Subaccount 6.5 - Environmental Studies will be used in conjunction with data from previous and ongoing studies to locate and design site specific multiple use restoration projects.

5. Develop opportunities for improving sediment detention, flood protection and water supply for environmental restoration. Study modification of existing detention facilities, new basins, and re-operation of existing reservoirs. Perform economic evaluation and tradeoff analysis of project performance. The reservoir operations data collected under Subaccount 6.9.A - Hydrology, and 6.9.C - Sedimentation will be used to determine if additional fine sediment can be trapped in a cost-effective manner, thus reducing the fine grain contribution to the Bay. Channel stability analyses under 6.9.C will consider the fine grained basins.

6. Update recreation needs assessment and user opportunities. Study recreational constraints and opportunities. Data collected under Subaccount 6.5 - Environmental and Subaccount 6.7 - Economics will be used to assess the needs, opportunities, and costs associated with recreation. Early identification of recreational features for existing and planned water resource projects will increase the likelihood of inclusion.

7. Improve public awareness of watershed issues by developing a website and periodical newsletter for the watershed and bay, encouraging community education programs, and assisting in the development of river restoration oriented science curriculum guidelines for local schools and volunteer groups. Public awareness is addressed under Subaccount 6.1 - Public Involvement.

The technical, institutional, and social data collected and generated in the study is integrated under Subaccount 6.14 - Plan Formulation. The baseline condition (existing and future without project) is defined. Project alternatives are generated, evaluated and refined in an iterative process. The with-project condition for each alternative is compared against the baseline, and the benefits, costs and trade offs are determined. The recommended watershed plan, which will include both management practices and construction projects will be selected and justified on clearly defined criteria.

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3.3. "SPIN-OFF" SITE INVESTIGATIONS

During the development of the PLAN, specific sites within the watershed will be investigated for restoration purposes. Eleven "spin-off" sites have been identified during the reconnaissance study, and are listed in Section VI, 6.14, Plan Formulation of the PSP. Site locations are shown on the study map. Some sites may be deleted, or additional sites added, during the course of the feasibility study based on more detailed investigations. Time and costs associated with the spin-off sites are based on investigation of eleven sites. Study costs will be adjusted accordingly if the number of sites change.

A reconnaissance-level investigation of the spin-off sites will be included as part of the baseline studies, and will provide enough information for decisions in regards to initiating spin-off feasibility studies. Recommendations regarding Federal involvement in implementable projects at these sites will also be determined through this study.

If a specific project(s) can be identified for implementation under an existing Corps authority, then a spin-off feasibility study will be undertaken and cost-shared with the appropriate local sponsor(s). At the F3 Milestone (see Section V. Milestones) potential spin-off studies will be identified. By the F4 Milestone, individual PSP's for each spin-off study will be completed. The watershed feasibility study will document the initial results of site specific investigations and the impacts of construction the sites on the watershed and bay (i.e. additional sediment trapping, water quality improvements, etc.)

The spin-off feasibility reports will include the appropriate level of site specific planning and engineering detail (i.e., engineering appendices, real estate appendix, NEPA documentation) necessary to implement the proposed project. This will allow decision-makers to complete the appropriate technical and policy review, and will provide a report that can become the basis for congressional authorization of a specific project. Projects that are part of the watershed management plan, but fall outside of the Corps mission, can be implemented by other interested local, state, and federal agencies.

The watershed management plan and products generated under this Project Study Plan are not intended to produce an implementation document for authorization by Congress. Rather, the study will provide a decision-making framework within which specific structural projects, nonstructural projects, and local activities will be identified, and additional, site specific, spin-off studies may be recommended for implementation. The watershed management plan will be the overall blueprint for watershed improvement activities.