Big Lagoon Estates Area of Deferred Certification North Coast Area Plan Humboldt County Local Coastal Program Proposed Amendment Recommendation
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Humboldt State University Digital Commons @ Humboldt State University Humboldt State University Sea Level Rise Student Projects Initiative 5-15-2015 Big Lagoon Estates Area of Deferred Certification North Coast Area Plan Humboldt County Local Coastal Program Proposed Amendment Recommendation Kyle Copp Patrick Flynn Evan Johnson Sarah West Follow this and additional works at: https://digitalcommons.humboldt.edu/hsuslri_student Big Lagoon Estates Area of Deferred Certification North Coast Area Plan Humboldt County Local Coastal Program Proposed Amendment Recommendation Humboldt State University Environmental Management & Protection Natural Resources Planning Senior Practicum 2015 May 15, 2015 Final Draft (Version 6) Kyle Copp, Patrick Flynn, Evan Johnson, Sarah West Contact: Sarah West - [email protected] Emergency Contact: Dr. Yvonne Everett, Professor of Environmental and Natural Resources Planning, Department of Environmental Science and Management, HSU (707) 826-4188; [email protected] Figure Title or Description of Figure Section, # Page # 1 Initial conceptual model to address bluff retreat and rural housing services and needs for the certification of the Big 1.1, 7 Lagoon Estates into the Humboldt County LCP. 2 Land Use Map of the Big Lagoon area. 2.2, 10 3 Shows the spatial location within the ADC of the referenced CCC memoranda and geotechnical reports. Each property 3.2, 16 associated with a CCC memo is distinguished by color, and the geotechnical reports associated with each APN are shown. 4 Historical retreat of the bluffs adjacent to the northern region of the Big Lagoon Subdivision ADC. 3.3, 24 5 & 6 Distances of structures from bluff edge in Big Lagoon Subdivision. Notice some houses eastward of Roundhouse Creek 3.4.3, 26 Road are closer to the bluff edge than those within the ADC. 7 Left picture is of the bluff face along Big Lagoon Park and the right picture is the bluff face along the Big Lagoon 8, 35 Subdivision of deferred certification (Michalak 2015). 8 South facing photo taken from northernmost point of Big Lagoon bluffs during the 1998 storm surge (Michalak 2015). 8, 36 9 North facing photo of northernmost Big Lagoon Subdivision bluffs (near view) with high intensity wave cutting action; 8, 36 and the southernmost Big Lagoon Park bluffs (far view). This photo was taken from the northernmost point of Oceanview Drive (Michalak 2015). 10 North facing photo of bluffs between Big Lagoon Park and Big Lagoon Subdivision with high intensity wave cutting 8, 37 action. This photo was taken from midpoint of Oceanview Drive (Michalak 2015). 11 South facing photo of Big Lagoon Subdivision bluffs with high intensity wave cutting action (Michalak 2015). 8, 37 12 Land Uses & Zoning 8, 38 13 Historical Bluff Edges - Big Lagoon Subdivision - Central Region 8, 39 14 Historical Bluff Edges - Big Lagoon Subdivision - Southern Region 8, 40 15 Historical and Projected Bluff Edges - Big Lagoon Subdivision - Northern Region 8, 41 16 Historical and Projected Bluff Edges - Big Lagoon Subdivision - Central Region 8, 42 17 Historical and Projected Bluff Edges - Big Lagoon Subdivision - Southern Region 8, 43 18 Proposed Setback Buffer - 189 feet 8, 44 19 Distances of structures in northern region of Big Lagoon Estates from bluff edge. 8, 45 20 Distances of structures in central region of Big Lagoon Estates from bluff edge. 8, 46 21 Distances of structures in southern region of Big Lagoon Estates from bluff edge. 8, 47 Page | 1 Acknowledgments The development of this report would not have been possible without the involvement of the following individuals: ● John Miller ○ Senior Planner, Advanced Planning Division, Humboldt County Planning & Building Department ● Don Tuttle ○ Retired Director of Public Works & Former Resource Analyst for Humboldt County ● Dr. Mark Johnsson ○ Staff Geologist, California Coastal Commission ● Bob Merrill ○ District Manager, North Coast District Office, California Coastal Commission ● Melissa Kraemer ○ Staff, North Coast District Office, California Coastal Commission ● Dr. Melanie Michalak ○ Staff, Department of Geology, Humboldt State University ● Illijana Asara ○ Chair of Big Lagoon Community Services District ● Dr. Laurie Richmond ○ Assistant Professor of Environmental Planning, Department of Environmental Science & Management, Humboldt State University ● Dr. Yvonne Everett ○ Endless Support & Guidance, Professor of Environmental Planning, Department of Environmental Science & Management, Humboldt State University Page | 2 Executive Summary Big Lagoon is a part of the highly variable and dynamic northern coastal region of California. The coastal environment of the southern Big Lagoon land area is composed a variably steep beach shoreline that sharply transitions into steep sheared bluffs (CCC 2014). Atop the bluffs is the Big Lagoon Estates subdivision bordered by spruce forests and a wetland bog. This particular region of the California coastal zone is a coastal interface that is continuously changing because of its consistent exposure to the highly active ocean environment, to human use, development of coastal resources, and the impacts and placement of existing urban development and planned areas of development. The Big Lagoon Estates is one of the several areas of deferred certification within the North Coast Area Plan of the Humboldt County Local Coastal Program. As Big Lagoon Estates fall within the coastal zone, the California Coastal Commission has jurisdiction and has identified that the land use designation and zoning do not appropriately reflect the coastal resources and hazards of this local coastal community for two reasons: (1) coastal erosion in the form of bluff retreat; and (2) inadequate fire flow capacity within the water services infrastructure, the improvement of which has the potential to impact sensitive bog habitat in the area. Humboldt County Senior Planner, John Miller, requested our assistance with this certification effort to provide a policy recommendation that addresses the issues identified by the California Coastal Commission. We assisted in this certification effort by developing policy options based on an understanding of the relevant policy framework and current geotechnical conditions and service infrastructure limitations of the area. We researched extensively, interviewed local experts, including the Humboldt County Planning Department and California Coastal Commission staff and conducted field visits in an effort to inform our geological, technical and spatial analysis of the issues. We found that bluff retreat in the area of Big Lagoon Estates Area of Deferred Certification surpasses land use designations and zoning adjacent to the Area of Deferred Certification. Further, improvement of service infrastructure is a prerequisite for expansion of services to accommodate potential future development and planned retreat; improvement will not affect sensitive habitat in the area. Based on these findings, and with consideration to potential policy options, we recommend an update of the Land Use and Implementation Plans to address coastal hazard by creating a Coastal Erosion Hazard land use designation that incorporates open space land use standards and those special conditions of the Coastal Commission’s Coastal Development Permit policy rulings for otherwise non-conforming structures and future development. Page | 3 Contents 1 Introduction ...................................................................................................................................................... 5 1.1 Issues .......................................................................................................................................................... 6 2 Review of Policy Framework ............................................................................................................................ 7 2.1 Standards of Review .................................................................................................................................. 7 2.2 Current Land Use and Implementation Plan .......................................................................................... 9 3 Bluff Retreat Research & Findings ................................................................................................................ 10 3.1 Introduction ............................................................................................................................................. 10 3.1.1 Setting ................................................................................................................................................. 11 3.1.2 Geology ............................................................................................................................................... 11 3.1.3 Mechanism, Amplifiers, & Models of Bluff Retreat ......................................................................... 11 3.2 Literature Review .................................................................................................................................... 13 3.2.1 Setbacks ............................................................................................................................................ 16 3.2.2 Long-term Erosion Rates ................................................................................................................ 16 3.2.3 Short-term Erosion Rates ................................................................................................................ 18 3.3 Our