Figure 21. Site on a mudflat vegetated with alkali
Figure 22. Site on a river levee with a tall stand of
grass and arrowgrass.
beach rye.
Table 9. Measurements of moisture contents obtained in May, June and August 1994, and measurements
of dry bulk density obtained in August 1994.
Dry bulk
Dry bulk
Depth Moisture content (% dry weight basis) density*
Depth Moisture content (% dry weight basis) density*
(cm) May 14 May 19 June 21 August* (g/cm3)
(cm) May 14 May 19 June 21 August* (g/cm3)
Site
Site
Permanently flooded
Mudflat
1
5
124
119
107
0.72
6
5
50
44
40
35
1.34
1
10
61
88
0.87
6
10
42
41
35
35
1.36
1
20
59
44
34
35
1.41
6
20
42
41
36
33
1.38
1
30
39
39
33
33
1.53
6
30
39
38
36
34
1.31
7
5
48
49
38
40
1.26
Intermittent pond
7
10
46
41
39
35
1.32
2
5
56
78
64
46
1.18
7
20
39
38
33
33
1.40
2
10
61
48
39
1.27
7
30
42
37
34
34
1.31
2
20
42
47
39
33
1.32
8
5
45
48
36
37
1.19
2
30
36
36
30
31
1.38
8
10
41
41
34
30
1.25
3
5
45
63
48
42
1.21
8
20
38
39
32
29
1.38
3
10
49
48
38
1.25
8
30
38
37
32
31
1.38
3
20
44
46
40
36
1.27
3
30
35
41
30
30
1.40
River levee
4
5
63
62
42
37
1.27
9
5
35
35
30
31
1.19
4
10
48
50
38
37
1.24
9
10
31
36
30
29
1.11
4
20
42
46
37
34
1.28
9
20
31
36
30
27
1.16
4
30
42
41
34
29
1.39
9
30
31
33
30
29
1.39
5
5
54
62
43
37
1.28
10
5
36
36
31
30
1.30
5
10
49
48
43
35
1.25
10
10
35
35
29
25
1.26
5
20
42
39
37
34
1.32
10
20
32
32
27
26
1.21
5
30
44
38
34
31
1.41
10
30
31
32
28
29
1.35
* Site 3 on Aug. 20, Sites 7, 8, 9 and 10 on Aug. 22, Sites 2, 4 and 5 on Aug. 23, Site 1 on Aug. 24.
and 17C for the ponded and mudflat sites and
The time periods when sediments were unsat-
15C on the river levee. The date of the maximum
urated are indicated by an increase in the mois-
average hourly temperature at 5 cm occurred in
ture probe resistances (Fig. 25 and 26). The length
June in the ponded sites and in June or July in the
of time the top 5 cm of sediment was unsaturated
mudflat sites (Table 10). Each of these days had
increased with increasing elevation (Fig. 27).
over 10 hours of sunshine (NOAA 1994). The aver-
Over the time period monitored, site 1, with the
age temperatures were lowest at 30 cm deep (15C
lowest elevation, was always saturated, while site
for ponded and mudflat sites and 13C for levee
10, the highest elevation, was always unsaturated
sites), and the date of maximum temperature oc-
(Table 10). Unsaturated sediments were detected
curred later than at shallower depths.
at 5 cm deep at the two intermittent ponded site
19
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