SUNRISE PARK and BEACH Preliminary Engineering/Consulting Erosion Study
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SUNRISE PARK AND BEACH Preliminary Engineering/Consulting Erosion Study Lake Bluff Park District May 30, 2019 May 23, 2019 Ron Salski, Executive Director Lake Bluff Park District 355 W. Washington Avenue Lake Bluff, Illinois 60044 [email protected] SUBJECT: Sunrise Park and Beach: Preliminary Engineering/Consulting Erosion Study Draft Report Dear Ron: Enclosed is a final draft report summarizing the preliminary engineering study of options to upgrade Sunrise Park and Beach. Please let us know if you have additional comments. We are available to meet you at your convenience. The Park District acknowledges the financial support of NWSRD to complete this important report for future planning. NWSRD, Park District and Village of Lake Bluff have worked cooperatively to provide services for the residents and surrounding communities. Sincerely, William J. Weaver, PE, D.WRE Sam Shaffer Vice President – Sr. Principal Engineer Project Engineer Lake Bluff Park District Sunrise Park and Beach: Preliminary Engineering/Consulting Erosion Study TABLE OF CONTENTS DEFINITIONS ........................................................................................................................................... 4 1. Project Introduction and Background ........................................................................................ 6 2. History of the Lake Bluff Park District’s Sunrise Beach ....................................................... 9 3. Existing Site Conditions ................................................................................................................ 12 4. Engineering Issues and Assessment of Beach Environment ............................................ 20 A. Analysis Approach ................................................................................................................................... 20 Task 1: Field Observations .................................................................................................................................................... 20 Task 2: Compile Regional Beach Data and Information ............................................................................................ 20 Task 3: Base Map Preparation .............................................................................................................................................. 20 Task 4: Coastal Wave Climate and Stone Size Evaluation ......................................................................................... 21 Task 5: Historic Analysis of Existing Beach Limits ...................................................................................................... 22 B. Regulatory Considerations ................................................................................................................... 23 5. Site Plan Analysis ........................................................................................................................... 25 6. Engineering Design for Selected Options .............................................................................. 26 A. Base Option ................................................................................................................................................ 27 B. Expanded Base Option ........................................................................................................................... 30 C. Lakefill Option ........................................................................................................................................... 32 D. Island Breakwater .................................................................................................................................... 35 APPENDIX A 36 RENDERING 1 – 2018 CONDITIONS ......................................................................................................... 37 RENDERING 2 – 2018 CONDITIONS W/ HISTORIC BEACH POSITIONS NOTED ......................... 38 RENDERING 3 – BASE OPTION .................................................................................................................. 39 RENDERING 4 – EXPANDED BASE OPTION ........................................................................................... 40 RENDERING 5 – BASE OPTION WITH LAKEFILL ................................................................................... 41 RENDERING 6 – BASE OPTION WITH LAKEFILL CROSS SECTION (TALL TREES) ..................... 42 RENDERING 7 – BASE OPTION WITH LAKEFILL CROSS SECTION (LOW VEGETATION) ......................... 43 APPENDIX B 44 DRAWING B1 – 2018 CONDITION .............................................................................................................. 45 DRAWING B2 – BASE OPTION .................................................................................................................... 46 DRAWING B3 – EXPANDED BASE OPTION ............................................................................................. 47 DRAWING B4 – BASE OPTION WITH LAKEFILL .................................................................................... 48 DRAWING B5 – LAKEFILL SECTIONS ...................................................................................................... 49 AECOM 3 Sunrise Park and Beach: Preliminary Engineering/Consulting Erosion Study Lake Bluff Park District DEFINITIONS drift, comprised of sand carried by water currents, and 100-year Lake Storm Event creates the potential for sand to deposit on the beach. A wave event that has a 1% chance of occurring any given year. Wave events are based on the combined probability of lake level and wave heights. In this area, a general rule Beach Planforms of thumb would consider the combination of a 20 year The shape or outline of a beach as projected upon a recurrence interval wave height (5% chance of exceedance horizontal plane. This term generally refers to the plan view in any given year) and a 10 year recurrence interval lake shape of the beach at the normal water line. The shape level (10% chance of exceedance in any given year) would of the beach at the waterline are influenced by types and produce a 100 year event. The same is true of a combination extent of coastal structures that form the boundaries of the of a 10- year wave height and a 20- year lake level. Coastal beach cell. structure design considers a variety of combinations in order to design for that combination that produces the Breakwater worst case from a design perspective. Stone or solid structures constructed to absorb or reflect wave attack to provide a relatively quiescent zone landward Central Beach Gravel Maintenance Road of approaching waves. (Gravel Maintenance Road) The Central Beach contains a maintenance road that is Buttress constructed of gravel and located on the west edge of the A support built against a wall. For this project, buttress beach. This maintenance road is usually buried in sand structures are comprised of armor stone placed against except when it is damaged by wave attack. steel or other stone structures to provide structural support, or to enhance wave management function. ACES Computer Program Automated Coastal Engineering System is a collection Deepwater Wave Height of coastal engineering software that is used to provide A term used to describe waves in very deep water that have a comprehensive system for using a broad spectrum of heights and wave direction unaltered by the action of lake coastal engineering analysis. bottom bathymetry and depth. Armor Stone Dune Plantings Armor stone is large heavy stone that is sized to withstand Vegetation that stabilizes the sand dune and prevents the forces of broken and unbroken wave attack. It is usually erosion. constructed with a range of stone sizes nested together to act as a stone fabric. The stone quality is specified to be Erosion durable for the coastal environment. The stone is usually The gradual destruction or diminution of something by obtained from quarries in Wisconsin that can meet required wind, water, or other natural agents. For this project, erosion quality specifications. generally refers to the loss of beach, beach sand, bluff soil, and lakebed clay due to the action of wave action or wave Bathymetry overtopping of structures. The measurement of depth of water in the lake and presented as a topography of the lake floor. Flow Separation When a fluid moves along the surface of an object causing Beach Cell it to detach from its original path and takes the form of an A beach cell is formed when structures are installed in the eddy or vortex. lake in a way that allows for the formation of a beach. The orientation of the structures in the cell influences the littoral 4 AECOM Lake Bluff Park District Sunrise Park and Beach: Preliminary Engineering/Consulting Erosion Study Groin Tombolo A long, narrow structure built into the water from a shoreline An expansion of the sand beach in the wave shadow of an that interrupts the water flow and limits the movement of island breakwater. This occurs due to the reduction of wave sediment to prevent beach erosion and accumulate sand. energy landward of the breakwater that slows the water currents and allows sand particles to fall to the lake bottom. Littoral Drift The transport of non-cohesive sediments along the shore Uprush due to the action of the breaking waves and the current The movement of water up the beach face or other structure along the shore. due to the breaking of a wave. Longshore Current Wave Convergence Wind induced water currents cause water