341
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
100
1 ,000
10,000
Maximum Channel Velocity (m/s); a
B /a
O
Channel Cross-Sectional Area (m 2 )
Escoffier Curve
O'Brien P/A relationship
Jarrett P/A twin jetties Pacific coast
aB/aO
1990 Position
2015 Position
Fig. 10.21 Escoffier Diagram for Lake Macquarie indicating an unstable scouring mode. The
O’Brien and Jarrett P/A relationships indicate a sixfold increase in channel area for the estuary to
reach equilibrium
Fig. 10.22 Lake Wagonga, Narooma NSW (Courtesy Google earth). The plan area of the bay is
7 km
2 . The jetties intersect the surf zone, the channel appears deeply scoured and there are significant flood tide sand deltas entering the bay
10 Long Term Impacts of Jetties and Training Walls on Estuarine Hydraulics…
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
100
1 ,000
10,000
Maximum Channel Velocity (m/s); a
B /a
O
Channel Cross-Sectional Area (m 2 )
Escoffier Curve
O'Brien P/A relationship
Jarrett P/A twin jetties Pacific coast
aB/aO
1990 Position
2015 Position
Fig. 10.21 Escoffier Diagram for Lake Macquarie indicating an unstable scouring mode. The
O’Brien and Jarrett P/A relationships indicate a sixfold increase in channel area for the estuary to
reach equilibrium
Fig. 10.22 Lake Wagonga, Narooma NSW (Courtesy Google earth). The plan area of the bay is
7 km
2 . The jetties intersect the surf zone, the channel appears deeply scoured and there are significant flood tide sand deltas entering the bay
10 Long Term Impacts of Jetties and Training Walls on Estuarine Hydraulics…