FIGURE 6 (a) Adelaide’s Living Beaches Strategy (b) Piping sand from north to south along Adelaide’s beaches
(a)
(b)
Key
Potential sand source Section Bank
Carting by truck Dredging (potential) Pipeline (proposed) Jetty Breakwater Breakwater (possible) Groyne Possible discharge points
Largs Bay
Semaphore
Slow sand movement to accumulate sand in this area
Torrens Outlet
Move sand south to recycle within littoral cell
Pipeline or carted by truck
Glenelg
Potential sand from Yorke Peninsula
Brighton
Potential dredging from Port Stanvac
Carting from Mt Compass
0
10
20km
Source: Spatial Vision
SkillBuilder discussion Geographical inquiry 1. Identify and classify the management strategies shown in FIGURE6a . 2. What would happen if sand was not moved from one end of the beach to the other? 3. Suggest a reason for the discharged sand appearing to be black. 4. Discuss whether this strategy will have a positive or negative impact on the beach environment.
13.11.3 Do coastal management strategies work? An integrated strategy like Adelaide’s Living Beaches Strategy has a better chance of protecting coastal landscapes and nearby structures, because it considers prevailing wind conditions and sand movement.
Building structures like groynes ( FIGURE7 ) on abeach can trap sand, but this disrupts longshore drift, and this can also reduce sand flow to beaches further along the coast. Sea walls or breakwaters may interrupt longshore drift, causing silt build-up at harbour mouths and increasing erosion on unprotected nearby coasts. Additionally, sea walls can reduce erosion from cliffs that naturally replenish beach sand. Coastal management is challenging: should we protect existing landscapes or allow wind and wave actions to create naturally evolving ones?
FIGURE7 A groyne on Cottesloe Beach
Groyne
340 Jacaranda Humanities Alive 8 Victorian Curriculum Third Edition
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