Quaternary (Late Pleistocene) alluvium.
Stagnant alluvial plain - defined as an alluvial plain where erosion and aggradation, by channelled and over-bank stream flow, is barely active or inactive due to reduced water supply.
An interactive visualisation of the landscape in the Denison mapping unit is provided here. Zooming and panning functionality is provided as well as the ability to click on icons to provide further information about the landscape (e.g. soils, geology).
Photo
Panoroma
Information
Soil reference site
Video
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Prior to the incision of the modern stream system, earlier stream systems (referred to as prior streams) deposited alluvium that now makes up the Tinamba, Denison and Montgomery map units. The Denison map unit occurs on what was then the far flood plain of these earlier stream systems, with redder soils of the Tinamba map unit occurring closer to the prior stream channels themselves. The surface soils on the far flood plains of the earlier stream systems are usually finer and heavier textured than the soils closer to the prior stream channels. Whilst the Montgomery map unit also occurs on the far flood plains, the surface soils are deeper and the overall profile less clayey than the soils of the Denison map unit.
This photo shows an extensive area of the Denison (De) map unit south of Cowwarr. Note the drainage depressions within the area. The Tinamba (Ti) map unit (redder soil) occurs in the eastern part of the Cowwarr township. The extensive river flats Thomson map unit (Th) are in the middleground.
It is likely that this map unit was predominantly grassland (Lunt, 1997). Skene and Walbran (1948,1949) described these areas as sparsely timbered plains. The more westerly occurrences did carry scattered red gum (Eucalyptus camaldulensis).
The soils have a dark greyish brown clay loam surface soil with a greyish brown clay loam to light clay sub-surface which is sporadically to conspicuously bleached. An abrupt to clear change occurs at about 20 to 35 cm to a mottled greyish brown to dark brown, medium to heavy clay. This clay continues to at least 1 metre depth. The area of the Denison map unit east of Clydebank, has a light clay to silty clay loam deeper subsoil rather than heavy clay [referred to as Denison clay loam, light phase by Skene and Walbran, (1949)]. The soils in this map unit are generally classified as Brown or Yellow Sodosols using the Australian Soil Classification.
Analyses are provided below for soil pit Site GP31 [equivalent to Type IV, Newell (1962)] and Site GP66 [equivalent to Denison clay loam, Skene and Walbran (1948)] which are in this map unit. Analyses of six profiles on this map unit are provided below from Skene and Walbran (1948, 1949). A profile on this map unit is also described by Aldrick et al. (1992).
The surface soils generally have a pH of between 5.5 and 6.0 in the surface and become alkaline with depth. All subsoils analysed were sodic to strongly sodic.
Depth cm | Texture | pH | EC dS/m | Cl % | Nitrogen % | Carbon % | Ca meq% | Mg meq% | K meq% | Na meq% | H meq% | ESP % | Gravel % | Coarse sand % | Fine sand % | Silt % | Clay % | LAT % |
0-25 | FSCL | 6 | 0.06 | 0.13 | 1.5 | 3.8 | 1.5 | 0.3 | 0.3 | 2 | 21 | 48 | 27 | 1 | ||||
25-35 | CL | 6.1 | 0.08 | 2.0 | 2.0 | 0.4 | 0.4 | 4 | 19 | 44 | 33 | <1 | ||||||
35-60 | LMC | 7.1 | 0.11 | 2.8 | 7.0 | 0.4 | 1.3 | 12 | 3 | 9 | 28 | 60 | 1 | |||||
60-110 | MHC | 8.5 | 0.21 | 2.8 | 8.2 | 0.4 | 2.0 | 15 | 1 | 5 | 33 | 61 | 1 | |||||
110+ | MC | 9.0 | 0.20 | 2.0 | 6.6 | 0.3 | 2.4 | 22 | 1 | 6 | 39 | 54 | 1 |
Depth cm | Texture | pH | EC dS/m | Cl % | Nitrogen % | Carbon % | Ca meq% | Mg meq% | K meq% | Na meq% | H meq% | ESP % | Gravel % | Coarse sand % | Fine sand % | Silt % | Clay % | LAT % |
0-10 | ZCL | 5.4 | 0.28 | 0.36 | 3.7 | 4.4 | 3.3 | 1.2 | 0.4 | 4 | 24 | 31 | 32 | 2 | ||||
10-20 | CL | 5.7 | 0.10 | 2.6 | 2.1 | 0.7 | 0.4 | 3 | 28 | 34 | 35 | 1 | ||||||
20-35 | MC | 6.0 | 0.07 | 2.8 | 5.5 | 0.6 | 1.0 | 6 | 13 | 20 | 61 | 1 | ||||||
35-50 | HC | 7.0 | 0.12 | 3.2 | 8.9 | 0.5 | 2.1 | 15 | 2 | 10 | 18 | 70 | 1 | |||||
50-90 | HC | 8.1 | 0.30 | 3.0 | 10.0 | 0.5 | 3.8 | 22 | 1 | 10 | 19 | 70 | 1 | |||||
90+ | HC | 8.9 | 0.07 | 2.9 | 9.5 | 0.5 | 7.4 | 37 |
Depth cm | Texture | pH | EC dS/m | Cl % | Nitrogen % | Carbon % | Ca meq% | Mg meq% | K meq% | Na meq% | H meq% | ESP % | Gravel % | Coarse sand % | Fine sand % | Silt % | Clay % | LAT % |
0-13 | CL | 5.7 | 0.15 | .016 | 0.351 | 4.36 | 3 | 19 | 38 | 31 | 1 | |||||||
13-23 | CL | 6.1 | 0.08 | .010 | 3 | 19 | 39 | 33 | 1 | |||||||||
23-30 | LC | 6.5 | 0.07 | .010 | 3 | 17 | 39 | 35 | 1 | |||||||||
30-53 | HC | 7.4 | 0.27 | .034 | 2 | 6 | 20 | 66 | 2 | |||||||||
53-91 | HC | 8.7 | 0.41 | .051 | 1 | 6 | 27 | 61 | 2 | |||||||||
91-147 | MC | 9.0 | 0.36 | .050 | 6 | 16 | 24 | 50 | 2 | |||||||||
147-183 | MC | 8.9 | 0.19 | .046 | 6 | 18 | 18 | 52 | 1 | |||||||||
183-213 | MC | 9.0 | 0.08 | .046 | 6 | 20 | 17 | 52 | 1 | |||||||||
213-244 | LC | 9.0 | 0.34 | .047 | 2 | 30 | 21 | 44 | 1 | |||||||||
244-279 | ZC | 8.8 | 0.37 | .047 | <1 | 7 | 38 | 50 | 1 | |||||||||
279-310 | ZC | 8.7 | 0.36 | .047 | 1 | 13 | 42 | 41 | 1 |
Depth cm | Texture | pH | EC dS/m | Cl % | Nitrogen % | Carbon % | Ca meq% | Mg meq% | K meq% | Na meq% | H meq% | ESP % | Gravel % | Coarse sand % | Fine sand % | Silt % | Clay % | LAT % |
0-10 | CL | 5.8 | 0.11 | .009 | 0.218 | 3.06 | 4.7 | 3.1 | 0.5 | 0.3 | 1 | 29 | 37 | 25 | 2 | |||
10-24 | CL | 5.8 | 0.06 | .002 | 1 | 30 | 37 | 27 | 1 | |||||||||
24-34 | CL | 6.0 | 0.06 | .003 | 2 | 29 | 35 | 29 | 2 | |||||||||
36-62 | HC | 6.6 | 0.19 | .022 | 1 | 11 | 20 | 61 | 2 | |||||||||
62-89 | HC | 8.7 | 0.40 | .033 | <1 | 9 | 24 | 62 | 2 | |||||||||
89-139 | MC | 8.7 | 0.29 | .034 | <1 | 17 | 34 | 46 | 1 | |||||||||
139-187 | LC | 8.8 | 0.27 | .033 | <1 | 12 | 43 | 41 | 1 |
Depth cm | Texture | pH | EC dS/m | Cl % | Nitrogen % | Carbon % | Ca meq% | Mg meq% | K meq% | Na meq% | H meq% | ESP % | Gravel % | Coarse sand % | Fine sand % | Silt % | Clay % | LAT % |
0-14 | CL | 6.0 | 0.15 | .013 | 0.169 | 1.96 | 3.8 | 1.8 | 0.3 | 0.2 | 8.6 | 1 | 1 | 17 | 45 | 32 | 1 | |
14-24 | CL | 5.7 | 0.08 | .005 | 2.5 | 2.2 | 0.3 | 0.2 | 8.2 | 1 | 1 | 15 | 43 | 36 | 1 | |||
24-34 | LC | 5.9 | 0.08 | .006 | 1 | 14 | 38 | 43 | 2 | |||||||||
34-50 | HC | 6.4 | 0.14 | .013 | 1.6 | 10.7 | 0.6 | 2.1 | 8.3 | 9 | <1 | 5 | 21 | 68 | 2 | |||
50-67 | HC | 7.6 | 0.21 | .019 | <1 | 3 | 20 | 70 | 1 | |||||||||
67-89 | HC | 8.4 | 0.25 | .026 | 3.7 | 11.7 | 0.6 | 3.5 | 0 | 18 | <1 | 3 | 25 | 66 | 1 | |||
89-144 | HC | 8.7 | 0.33 | .036 | <1 | 5 | 28 | 63 | 1 | |||||||||
144-187 | HC | 8.7 | 0.35 | .041 | <1 | 6 | 22 | 66 | 1 |
Depth cm | Texture | pH | EC dS/m | Cl % | Nitrogen % | Carbon % | Ca meq% | Mg meq% | K meq% | Na meq% | H meq% | ESP % | Gravel % | Coarse sand % | Fine sand % | Silt % | Clay % | LAT % |
0-15 | CL | 6.5 | 0.10 | .005 | 0.142 | 1.68 | 2 | 311 | 35 | 27 | 1 | |||||||
15-36 | LC | 6.0 | 0.05 | .004 | 2 | 30 | 32 | 32 | 1 | |||||||||
36-69 | HC | 6.5 | 0.11 | .013 | 8 | 5 | 10 | 15 | 63 | 1 | ||||||||
69-112 | HC | 8.2 | 0.21 | .022 | 3 | 2 | 10 | 19 | 67 | 1 | ||||||||
112-147 | HC | 8.9 | 0.23 | .019 | 1 | 16 | 18 | 62 | 1 |
Depth cm | Texture | pH | EC dS/m | Cl % | Nitrogen % | Carbon % | Ca meq% | Mg meq% | K meq% | Na meq% | H meq% | ESP % | Gravel % | Coarse sand % | Fine sand % | Silt % | Clay % | LAT % |
0-8 | CL | 6.3 | 0.08 | .004 | 0.188 | 2.39 | 3.0 | 2.1 | 0.4 | 0.2 | 3 | 33 | 32 | 25 | <1 | |||
8-15 | CL | 5.8 | 0.05 | .003 | 3 | 33 | 32 | 28 | 3 | |||||||||
15-30 | LC | 6.0 | 0.05 | .007 | 2.5 | 2.0 | 0.3 | 0.4 | 3 | 32 | 30 | 33 | 1 | |||||
30-53 | HC | 6.5 | 0.12 | .010 | 2.5 | 6.6 | 0.6 | 2. 1 | 18 | 2 | 18 | 18 | 56 | 2 | ||||
53-66 | HC | 7.6 | 0.18 | .018 | 1 | 4 | 12 | 17 | 64 | 1 | ||||||||
66-97 | HC | 8.3 | 0.27 | .030 | 2.7 | 10.6 | 0.7 | 3.9 | <1 | 22 | 1 | 11 | 17 | 67 | 1 | |||
97-162 | HC | 8.8 | 0.10 | .037 | 1 | 10 | 18 | 67 | 1 | |||||||||
162-221 | HC | 8.8 | 0.16 | .041 | 1 | 10 | 21 | 63 | 1 |
Depth cm | Texture | pH | EC dS/m | Cl % | Nitrogen % | Carbon % | Ca meq% | Mg meq% | K meq% | Na meq% | H meq% | ESP % | Gravel % | Coarse sand % | Fine sand % | Silt % | Clay % | LAT % |
0-20 | CL | 5.7 | 0.13 | .018 | 0.202 | 2.44 | 5.3 | 2.3 | 0.2 | 0.3 | 3 | 41 | 30 | 21 | 2 | |||
20-36 | CL | 5.7 | 0.16 | .020 | 1 | 45 | 29 | 22 | 1 | |||||||||
36-43 | CL | 5.8 | 0.16 | .024 | 1 | 42 | 28 | 25 | 1 | |||||||||
43-71 | MC | 6.5 | 0.34 | .053 | 4.1 | 7.9 | 0.1 | 1.5 | 11 | <1 | 34 | 17 | 43 | 2 | ||||
71-89 | LC | 7.4 | 0.39 | .053 | <1 | 42 | 19 | 33 | 1 | |||||||||
89-114 | LC | 8.7 | 0.44 | .060 | 1 | 23 | 38 | 33 | 1 | |||||||||
114-157 | MC | 9.4 | 0.51 | .059 | 20 | 1 | 21 | 26 | 47 | 3 |
Depth cm | Texture | pH | EC dS/m | Cl % | Nitrogen % | Carbon % | Ca meq% | Mg meq% | K meq% | Na meq% | H meq% | ESP % | Gravel % | Coarse sand % | Fine sand % | Silt % | Clay % | LAT % |
0-10 | CL | 5.5 | 0.10 | .010 | 0.29 | 3.17 | 1.8 | 1.9 | 0.6 | 0.5 | 12.8 | 3 | 4 | 28 | 37 | 23 | ||
10-18 | CL | 5.4 | 0.06 | .007 | 0.14 | 1.43 | 1.0 | 1.3 | 0.3 | 0.4 | 10.4 | 3 | 5 | 30 | 50 | 13 | ||
20-30 | ZCL | 5.7 | 0.06 | .006 | 0.065 | 0.59 | 0.9 | 2.1 | 0.2 | 0.6 | 7.0 | 6 | 4 | 30 | 39 | 26 | ||
30-60 | HC | 7.5 | 0.33 | .036 | 3.0 | 11.2 | 1.0 | 4.5 | 5.4 | 18 | 1 | 1 | 9 | 17 | 71 | |||
90-120 | HC | 8.4 | 0.90 | .11 | 1.9 | 9.9 | 0.8 | 5.7 | 2.1 | 28 | <1 | 11 | 20 | 67 |
Where irrigation water is available, these soils are irrigated. The Skene and Walbran soil types: Denison clay loam and Nambrok clay loam, are regarded as the better soils, as they have a deeper surface soil and are slightly lighter in texture than Wandocka clay loam.