Sunrise Park and Beach Preliminary Engineering / Consulting Erosion - PowerPoint PPT Presentation

Lake Bluff Park District Sunrise Park and Beach Preliminary Engineering / Consulting Erosion Study June 17, 2019

Study Purpose – Study is an Outgrowth of Erosion Impacts Caused by High Lake Levels – Sand Losses • Permanent Loss of Base Clay that Underlies Sand • Beach Erosion • Protection of Bluffs – Evaluate Preventative Measures that Address Current Damage and Anticipated Future Damage – Plan Now to Preserve the Beach Asset: Current High Water Lake Levels are similar to Historic Conditions in the 1970’s and 1980’s 2 Lake Bluff Beach Erosion Study

Beach Sand Loss 3 Lake Bluff Beach Erosion Study

Beach Clay Foundation Soil Loss 4 Lake Bluff Beach Erosion Study

Beach Condition Stressors Normal Conditions – Sand Ebbs and Flows to & From Beach – Wave Induced Beach Erosion in Surf Zone High Water Storm Conditions: * Sand Erosion Exposes Clay to Direct Wave Attack in Surf Zone * Native Stiff Clay Loss is permanent * Deep Water Allows Larger Waves to Approach Bluff Toe Sand Erosion Clay Erosion 5 Lake Bluff Beach Erosion Study

Report Content – Project Introduction and Background – History of the Lake Bluff Park District’s Sunrise Beach – Existing Site Conditions Evaluation – Site Plan Analysis – Engineering Design for Selected Options 6 Lake Bluff Beach Erosion Study

Historic Beach and Bluff Damage 7 Lake Bluff Beach Erosion Study 7

Historic Damage & Restoration (Central Beach) Looking North – Restroom/Guard Building Erosion (1973\1975) 8 Lake Bluff Beach Erosion Study

Historic Damage & Restoration (Central Beach) - Restroom/Guard Building Erosion (1973\1975) Looking South Lake Bluff Beach Erosion Study 9

Central Beach Restoration – 188’ Steel Groin Constructed (1976) - North Cell Breakwater Constructed (2000) 1998 Photograph 2017 Photograph Restroom/Guard Building Eroded West Groin End 10 Lake Bluff Beach Erosion Study

Historic Damage & Restoration (North of Dog Beach) – Bluff Erosion (Early 1970’s) 11 Lake Bluff Beach Erosion Study

Restoration (North of Dog Beach) -- Armor Stone Revetment (Constructed 1988) • Successful Erosion Protection • Unusable Beach – Safety Concerns in Park Setting 12 Lake Bluff Beach Erosion Study

Historic Damage & Restoration (South Beach) – Bluff Failure (1970’s) South Beach Area Bluff Failure NSWRD Looking South from Parking Lot 13 Lake Bluff Beach Erosion Study

South Beach Restoration – Breakwater Constr. & Bluff Restoration (Constructed 1991) 2018 Photograph 14 Lake Bluff Beach Erosion Study

Recent Damage – South End Central Beach – • Beach and Clay Lakebed Erosion – Central Beach North and South Cells • Beach and Lakebed Erosion South End Central Beach – Parking Lot & Groin Damage – South Beach Erosion South Beach Parking Lot 15 Lake Bluff Beach Erosion Study

Recent Damage – South End Central Beach • Beach and Clay Lakebed Erosion South End Central Beach 16 Lake Bluff Beach Erosion Study

Recent Damage 17 Central Beach South Cell Lake Bluff Beach Erosion Study

North Beach – Dog Beach – • Cobbles Dominate the Beach Surface • Rubble Pile Lake Bed Erosion 18 Lake Bluff Beach Erosion Study

Recent Nearby Beach & Bluff Damage Lake Forest 19 Lake Bluff Beach Erosion Study

Recent Nearby Beach & Bluff Damage Lake Bluff 20 Lake Bluff Beach Erosion Study

Beach Formation & Erosion Factors 21

Beach Condition Stressors – Lake Level Fluctuations (Monthly Average Lake Levels) • High Water allows larger waves to make it to shore without breaking and increases erosion potential Up to 6’ Fluctuation Record High Level >>>High Water Period 22 Lake Bluff Beach Erosion Study

Beach Condition Stressors – Storm Surge (Wind Setup) • Wind Storms can cause up to 3.5’ or more of Lake Level Rise Lake Michigan Level (October 2014 - 24 hour Storm) 2.5’ Level Fluctuation Wave Storm 23 Lake Bluff Beach Erosion Study

Beach Condition Stressors – Wave attack 24 Lake Bluff Beach Erosion Study

Beach Formation Dynamics! – Littoral Drift – Shoreline Character – Influence of Coastal Structures – Wave Climate – Beach Sand Sources: • Rivers • Ravines • Shoreline Erosion • Bluff Erosion 25 Lake Bluff Beach Erosion Study

Sunrise Beach Sand Formation Dynamics! – Littoral Drift – Shoreline Character – Influence of Coastal Structures – Wave Climate – Beach Sand Sources: • Rivers • Ravines • Shoreline Erosion • Bluff Erosion 26 Lake Bluff Beach Erosion Study

Existing Sunrise Beach Sand Formations 27 Lake Bluff Beach Erosion Study

Existing Sunrise Beach - Geometry 28 Lake Bluff Beach Erosion Study

Existing Sunrise Beach – Historic Beach Waterline Positions 29 Lake Bluff Beach Erosion Study

Engineering Design for Selected Options Lake Bluff Beach Erosion Study 30 30

Base Option 31 Lake Bluff Beach Erosion Study

Base Option 32 Lake Bluff Beach Erosion Study

Base Option - Comparison 33 Lake Bluff Beach Erosion Study

Base Option – Opinion of Probable Cost 34 Lake Bluff Beach Erosion Study

Expanded Base Option 35 Lake Bluff Beach Erosion Study

Expanded Base Option 36 Lake Bluff Beach Erosion Study

Expanded Base Option Comparison 37 Lake Bluff Beach Erosion Study

Expanded Base Option- Opinion of Probable Cost 38 Lake Bluff Beach Erosion Study

Base Option with Lakefill Expansion 39 Lake Bluff Beach Erosion Study

Base Option with Lakefill Expansion 40 Lake Bluff Beach Erosion Study

TALL TREE OPTION Base Option with Lakefill Expansion – Section Options LOW LEVEL VEGETATION AND BERM 41 Lake Bluff Beach Erosion Study

Base Option with Lakefill Expansion - Comparison 42 Lake Bluff Beach Erosion Study

Base Option with Lakefill Expansion- Opinion of Probable Cost 43 Lake Bluff Beach Erosion Study

2013 Master Plan Island Breakwater Concept 44 Lake Bluff Beach Erosion Study

Lake Bluff Park District Sunrise Park and Beach Preliminary Engineering / Consulting Erosion Study June 7, 2019