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HomeMy WebLinkAbout; Agua Hedionda Lagoon Shore Protection Prog; Agua Hedionda Lagoon Shore Protection Prog; 1995-04-17AGUA HEDIONDA LAGOON SHORE PROTECTION PROGRAM CITY OF CARLSBAD 4/17/95 ' AGUA HEDIONDA LAGOON SHORE PROTECTION PROGRAM INTRODUCTION The beaches and shoreline of California are among the State's primary resources. Attendance at Coastal State Parks and Beaches totaled more than 77,000,000, or 70%, of the total State Park attendance. Coastal campgrounds provide 52% of all State Park camping attendance. Coastal tourism and recreation totaled over $6 billion dollars in recent years which amounts to nearly 50% of the total value of all coastal dependent industries in the State. Our beaches and shorelines are clearly one of the State's major assets and, yet, investment to protect and enhance those resources are nearly non-existent. Over the years, as our beaches have receded and the coastal bluffs have become more and more exposed, all levels of government have pulled back resources and abandoned efforts to protect and enhance this most valuable of resources. These problems are most acute in San Diego County and, particularly, the coastal reaches extending from Oceanside to La Jolla. Due to the construction activities and neglect over the past thirty years, the north San Diego coastal areas have continually receded from the once wide sandy beaches to the existing narrow cobbled coast with precipitous exposed bluffs. This situation being most serious fronting the State beaches. If nothing is done to protect our coastline, we face a continual exposure to millions of dollars in damages to property and public infrastructure and additional millions in tost recreational benefits. OCEANSIDE HARBOR IMPACTS The most severe impacts on the Carlsbad coastline can be directly traced to the construction of the Oceanside Harbor by the Marine Corps during World War II. Immediately following this construction, down shore impacts to Oceanside and Carlsbad began to appear. As partial mitigation for this problem, the Del Mar Boat Basin was dredged in the early 1950's to provide down coast nourishment and to create a joint marine and small crafts harbor. The impacts of the harbor continue to plague both cities, which resulted in long-term studies and programs by the U.S. Army Corps of Engineers and the Department of Boating and Waterways to provide for beach nourishment and shoreline protection. CARLSBAD SHORE PROTECTION WALL The most recent project designed to address these long-standing issues is the Carlsbad Shore Protection Wall. This project will construct a 2,600 linear foot shore protection wall from Carlsbad Boulevard extending between the inlet and outlet jetties of the Agua Hedionda Lagoon. The proposed shore protection project would protect this major City investment, secure parking and beach access, and retain badly needed sand on the beach. As a part of the proposed project, the City and San Diego Gas and Electric (SDG&E) will provide periodic beach nourishment activities to ensure the maintenance of this valuable State resource. Sands currently placed on this beach are subject to severe erosion due to both wind action and coastal processes. The proposed shore protection project includes a parapet wall which extends above the sidewalk by 42 inches. This wall will provide a wind barrier which will significantly reduce City road maintenance costs and reduce erosion caused by wind action. The proximity of the project to the Agua Hedionda Lagoon makes this project multi- faceted including beach nourishment, lagoon environmental protection, assistance in protecting lagoon boating opportunities and securing the successful operation of the San Diego Gas and Electric (SDG&E's) Encina Power Generating Plant, and protection of a major regional highway and utility corridor. A more detailed summary of benefits include: > Reduction of siltation into the lagoon which impacts boating activities in the inner lagoon. *• State beach nourishment which provides recreational benefits to thousands each year. * Protection of $2.2 million fish hatchery which will lead to generation of up to $3 million in fishing products for commercial as well as recreational boaters each year. »• Protection of SDG&E power generation operations. » Lagoon protection for aquaculture operations valued at over $500,000. *• Protection for water, electrical, gas and communication facilities valued at $300,000. > Provision for fully accessible beach access and parking. BENEFIT ANALYSIS The project which is shown on the attached Exhibit 1 is being developed as a locally preferred option to a proposed Beach Fill/T-Groin project for which a Federal interest was confirmed in the January 1994 Pacific Coast Shoreline Carlsbad Reconnaissance Report. This project incorporates an annual beach maintenance program of up to 130,000 cubic yards of sand to provide maintenance of a 200 foot wide beach fronting the proposed seawall. The recreational benefits provided by this program have been calculated at $352,570 annually over the 50-year life of the project. The value of the beach fill provided through the combined efforts of the City and SDG&E is up to $390,000 annually. The public facility protection value has been calculated at a net value of $260,270 per year. Based on total project benefits of $1,002,870, the roadway protection component is somewhat less than 26% of the total project benefits. FINANCIAL PROGRAM Recognizing the extraordinary benefits of the Carlsbad Shore Protection Wall, a Federal- State-City partnership is being crafted to complete this project in the 1995-1996 budget year. The project is fully designed, permitted and ready for construction. Funding over $300,000 for design of the project was provided by the State Department of Boating and Waterways in 1991. The $4,700,000 construction cost is proposed to be funded by the following mix of funding: $2,000,000 U.S. Army Corps of Engineers 103 Continuing Authority Program $2,000,000 State Department of Boating and Waterways Funds $700,000 City Funds It is anticipated that the project would be constructed by the U.S. Army Corps of Engineers with a contract awarded in the Spring of 1996. SUMMARY AND CONCLUSION The Carlsbad Shore Protection Wall will provide the continued process of mitigating the impacts of the Oceanside Harbor by providing the following benefits: Provide beach nourishment Protect for boating on the Agua Hedionda Lagoon Protect Carlsbad Boulevard and its utilities Reduce beach erosion Protect lagoon resources Agua Hedionda Lagoon Bevanon vanes *- Slope 1%Present Limit of Sidewalk Existing Cure and Gutter New *' SlaB on Grade to Complete SidewaiK Two (2) Layer of 1.500 pound Stone Approx 4 ft Thick R«nf Cone Can -^ ^-J Undistumed Sou 4^^ I Use 30* Long Stwe« Piling Betnienem steet PLZ-23 or Syrd Ste* SPZ-23 or Approved Equal «incn Thick Quarry Him Material Underlain oy filter Fabric TYPICAL SECTION 0 4CX) 800 1200 Scale in feet CARLSBAD BOULEVARD SHORE PROTECTION WALL FIGURE 1 11888110M OCEANSIDE HARBOR IMPACTS HISTORICAL SEDIMENT DEFLECTION AT OCEANSIDE HARBOR ANNUALLY ABOUT 440,000 CY OCEANSIDE HARBOR CARLSBAD ACCRETION GREATER THAN 2 FT BETWEEN 1934-72 SUSPECTED SEDIMENT PATH AGUA HEDIONDA LAGOON PROJECT AREA PHOTOS