Lyme Regis Lyme Regis No longer Slip-sliding No longer Slip-sliding

AwayAway

September 1, 2006September 1, 2006

IntroductionIntroduction

LocationLocation

EnglandEngland Southwest CoastSouthwest Coast DorsetDorset Jurassic Coast World Jurassic Coast World

Heritage SiteHeritage Site Exposed to severe Exposed to severe

winter stormswinter storms

West, 2006

Stormy WeatherStormy Weather

Undated, 1970’s stormSource: West, 2006

Calm WeatherCalm Weather

The Geology of Lyme RegisThe Geology of Lyme Regis

GreensandGreensand ClayClay ShaleShale Blue LiasBlue Lias

Steep slopeSteep slope

The Beginnings of a LandslipThe Beginnings of a Landslip

Charmouth Road Car Charmouth Road Car ParkPark

Asphalt is contributing Asphalt is contributing to landslipto landslip

Work underway to Work underway to improve drainage improve drainage systemsystem

The Black VennThe Black Venn

Between Lyme Regis Between Lyme Regis and Charmouthand Charmouth

Mostly Clay and Mostly Clay and Shales with BeefShales with Beef

Prone to landslidesProne to landslides Rich source of fossilsRich source of fossils

The Blue LiasThe Blue Lias

West of Lyme Regis at West of Lyme Regis at Monmouth BayMonmouth Bay

GreensandGreensand ClayClay LimestoneLimestone

LandslidesLandslides

1962 Langmoor 1962 Langmoor GardensGardens

Caused by Caused by construction activitiesconstruction activities

The area was re-The area was re-graded and Langmoor graded and Langmoor gardens were gardens were establishedestablished

The SpittlesThe Spittles

East of Lyme RegisEast of Lyme Regis The whole system was The whole system was

reactivated in 1986reactivated in 1986

Long-shore drift interruptedLong-shore drift interrupted

Beach buildupBeach buildup Monmouth beach Monmouth beach Increased protectionIncreased protection

Beach depletionBeach depletion Shingle supply Shingle supply

interruptedinterrupted This results in depletionThis results in depletion

The depleted beach(1960’s) and The depleted beach(1960’s) and breached seawall (1974)breached seawall (1974)

Coastal Defenses - The CobbCoastal Defenses - The Cobb

Coastal ReinforcementsCoastal Reinforcements

Beacon Rocks extended by 110 metersBeacon Rocks extended by 110 meters North wall rockery realignedNorth wall rockery realigned Added rock armor at Cobb GateAdded rock armor at Cobb Gate New jetties at Lister Gardens and Cobb New jetties at Lister Gardens and Cobb

GateGate Beach replenishmentsBeach replenishments Sand and shingle Sand and shingle

Raised beach level by 2 metersRaised beach level by 2 meters

Beacon RocksBeacon Rocks

Armor rocks:Armor rocks: 11,000 tonnes core rock, 2 - 5 tonnes each11,000 tonnes core rock, 2 - 5 tonnes each 26,500 tonnes armor, 9 - 18 tonnes each26,500 tonnes armor, 9 - 18 tonnes each Source: Norwegian graniteSource: Norwegian granite

Byproduct of granite counter top industryByproduct of granite counter top industry

Shingle (pebbles):Shingle (pebbles): 72,000 tonnes72,000 tonnes Source: Isle of WightSource: Isle of Wight

Sand:Sand: 37,000 tonnes37,000 tonnes Source: northern FranceSource: northern France

Precast concrete:Precast concrete: Source: UKSource: UK

Limestone facingLimestone facing Source: ChinaSource: China

Rock Armor at Cobb Gate JettyRock Armor at Cobb Gate Jetty

Finishing up at Cobb Gate JettyFinishing up at Cobb Gate Jetty

Reinforcements at Cobb GateReinforcements at Cobb Gate

Lyme Harbor beach restoredLyme Harbor beach restored

Work continues at Langmoor Work continues at Langmoor GardensGardens

Slope stabilizationSlope stabilization

Began in 2005, scheduled completion 2007Began in 2005, scheduled completion 2007 Major engineering effort involved Major engineering effort involved

considerations for seismic stabilityconsiderations for seismic stability Only small equipment allowed until slope Only small equipment allowed until slope

was sufficiently stabilizedwas sufficiently stabilized Gradual increase in machinery size based Gradual increase in machinery size based

on monitoringon monitoring

1,150 auger-cast piling1,150 auger-cast piling Drilled holes thru clay into bedrockDrilled holes thru clay into bedrock Filled with concrete and reinforcementFilled with concrete and reinforcement Act as dowels to hold slopeAct as dowels to hold slope

Soil nailsSoil nails Similar to piling but horizontalSimilar to piling but horizontal

2,300 meters drainage 2,300 meters drainage Counterforts - at baseCounterforts - at base Drilled drains -in hillDrilled drains -in hill French drains - below car parkFrench drains - below car park

ConclusionConclusion

Phase II construction is nearly completePhase II construction is nearly complete Coastal defensesCoastal defenses Slope stabilizationSlope stabilization Increased security for townIncreased security for town Increased income due to tourismIncreased income due to tourism Cost to maintain will be less than the cost of Cost to maintain will be less than the cost of

emergency repairsemergency repairs