30
1.0
1.0
30
0.8
0.8
20
20
0.6
0.6
0.4
Temperature
0.4
Temperature
10
10
0.2
0.2
0
0
0
0
10
20
10
20
10
20
25
10
20
10
20
10
20
25
May
Jun
Jul
Aug
May
Jun
Jul
Aug
j. Site 10--River levee.
i. Site 9--River levee.
Figure 26 (cont'd).
62
100
y = 799.47 + 172.53x R = 0.96438
80
58
60
54
40
50
20
46
0
0
20
40
60
80
100
4.6
4.8
5.0
5.2
Pressure (cbars)
Elevation (m)
Figure 28. Moisture retention curve for a sediment
Figure 27. Number of days that sediments at 5 cm
sample collected 20 m south of the transect between
deep were unsaturated vs. elevation.
sites 3 and 4 in the intermittent pond.
weeks after a flooding tide and two and one-half
the surface sediments. The actual air-entry value
weeks before the next series of flooding high
in the field will vary with the heterogeneity of
tides.
the sizes of sediment pores. Sediment with
In May, water was present in all piezometers
cracks and channels (macropores) would have a
(Fig. 29). The water surface elevation was above
lower value (Hemond and Chen 1990).
or within 1 cm of the surface of the sediments at
Water surface elevations. Water surface eleva-
sites 17. At site 8, the mudflat site near the river
tions were recorded three times using piezome-
levee, water was 20 cm below the sediment sur-
ters. The first measurement was seven hours af-
face, and at site 9, on the river levee, it was 33 cm
ter a flooding high tide on May 24. The second
below the sediment surface. Between the May
measurement was on June 20, three and one-half
and June measurements, the water surface eleva-
weeks after a flooding tide and three days prior
tions dropped significantly at all sites except the
to the next series of flooding tides. The last mea-
permanently flooded site (site 1). On June 20, pi-
surement was on August 19, seven and one-half
27
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