Dredging and New Technology for Shoreline Restoration at TOF, Chayvo Beach Sakhalin October 07, 2010...

Dredging and New Technology for Shoreline Restoration at TOF,

Chayvo Beach Sakhalin

October 07, 2010

XXIII Международная Береговая Конференция в честь 100-летия со дня рождения

Профессора Всеволода Павловича Зенковича

Agenda

• Project description and objectives

• Chayvo beach shoreline existing conditions

• Shoreline stabilization alternatives and analysis

Project Objectives

• Develop solution to stabilize shoreline at Chayvo beach along TOF facilities with beneficial use of dredged material

Bathymetry – November 2009NOTE: 2006 Aerial

Bathymetry - 2002NOTE: 2004 Aerial

Wave statistical data at TOF facilities was developed based on offshore GROW wind and wave data (for the period 1996-2005. GROW data hindcasted wave heights and periods and wind speeds and directions at 3 hour interval for 10 years

10 m

140 m

Section of wave parameters extraction and averaging

No. of occurrences in the period 1996 to 2005 (only August); Direction 225 to 240

No. of occurrences in the period 1996 to 2005 (only August); Direction 240 to 255

All year – 225 DEG

(Direction TOWARD which waves propagate)

All year – 270 DEG

Predominant Sediment Transport

Transect 5

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

5817000 5817050 5817100 5817150 5817200 5817250 5817300 5817350 5817400 5817450 5817500

Northing [m] WGS 84 - UTM Zone 54

m B

alti

c

2002 ExistingAug 9 2005Aug 26 2005Sept 26 2005Dec 2005

s N

October 04, 2005

2004 2007

North Shoreline Dynamics Summary

• North Shoreline was accreted and progressed seaward. No erosion at this part of the shoreline has occurred during or after construction of the TOF in 2005-2006.

• No erosion occurred during the periods 2004-2007 and 2006-2008 along the North Section shoreline.

• North Section shoreline is in a stage of dynamic equilibrium between hydrodynamic, littoral, and geomorphologic processes. Sediment transport along this part of the shoreline appears to be sufficient to maintain beaches and the underwater offshore bars.

• No need for shoreline erosion protection or restoration is required

Central Shoreline Dynamics Summary

• Shoreline erosion starts from the south end of the Geobag Project and extends to the south. The erosion reduces with distance from the Well Site, and diminishes to an insignificant rate approximately 700 ft south of the Geobag Project.

• Erosion of the Well Site has occurred through deepening of the bottom slope and diminishing of the formation of the underwater bar system.

• Bottom deepening at the Well Site and Transition Shoreline reaches would continue if littoral drift conditions are not modified or re‑constructed to restore by-pass of sediment

2006 2008

South Shoreline Dynamics Summary

• No erosion has occurred during the periods 2004-2006 (based on aerial photographs) and 2006-2008 (based on survey profiles)

• South Section is in a stage of dynamic equilibrium between hydrodynamic, littoral, and geomorphologic processes. Sediment transport along this part of the shoreline is sufficient to maintain the beaches and underwater offshore bars. No need for shoreline erosion protection or restoration is required.

Seawalls Revetments

GroinsBreakwaters

Central Shoreline Causes of Erosion

• Insufficient bar formations on the bottom slope.

• Reduced ability of bottom slope to attenuate wave energy.

• Propagation of higher wave energy to the nearshore surf zone and Geobag Project.

• Wave reflection from Geobag Project resulting in increased wave energy and erosion on the bottom slope.

Low Crested Groins Expected Performance

• Create conditions for re-establishing of bar system on the bottom slope.

• Increase ability of bottom slope to attenuate wave energy.

• Reduce waves reflection from Geobag Project thus minimize erosion on the bottom slope

Demonstration Project

• In order to validate the proposed solution and obtain reliable data to complete final design a small shoreline protection demonstration project will be conducted during the TOF dredging project in 2011-2012.

• Monitoring data from the demonstration project will be collected starting from 2010 (prior to construction) through 2013 (one year after construction), and will provide the basis for development and selection of the preferred shoreline erosion protection solution.

Dredging and New Technology for Shoreline Restoration at TOF,

Chayvo Beach Sakhalin

October 07, 2010

XXIII Международная Береговая Конференция в честь 100-летия со дня рождения

Профессора Всеволода Павловича Зенковича

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