343
y = 0.003x - 5.4366
R 2 = 0.8396
y = 0.0033x - 5.9836
R 2 = 0.9083
0.50
0.51
0.52
0.53
0.54
0.55
0.56
0.57
0.58
0.59
0.60
0.61
0.62
0.60
0.61
0.62
0.63
0.64
0.65
0.66
0.67
0.68
0.69
0.70
0.71
0.72
1995
2000
2005
2010
2015
Bay Range/Ocean Range (a
B /a
O )
Mean Spring Tidal Range (MHWS-MLWS m)
Year
Spring Tidal Range
Bay Range/Ocean Range
Fig. 10.23 Change history of the mean spring tidal range in Lake Wagonga and its ratio to the
ocean range. The trends are strong (R
2 = 0.8–0.9) showing no signs of abating. With a plan area of
7 km
2 , the rate of increase in the spring tidal prism of 3 mm/a equilibrates to an annual increase in
the spring tidal prism of 20,000 m
3
y = -0.2359x + 530.74
R 2 = 0.8042
55
56
57
58
59
60
1995
2000
2 005
2010
2 015
Phase Lag (degrees)
Year
Fig. 10.24 Change history of the phase lag (bay phase minus the ocean phase) of the major spring
tidal constituent (M2) in Lake Wagonga. There is a strong reducing trend (R
2 = 0.8) indicating high
tide arriving sooner in the bay
10 Long Term Impacts of Jetties and Training Walls on Estuarine Hydraulics…