slopes sandy loam over mottled yellow clay, with scattered limestone outcrops. areas silver-leaved box, sparse low woodland (E. pruinosa) with Tippera tall grass. 3 20 Crests and low rises Limestone outcrops with pocket of Tippera in north and of Tobermorey in south. As unit 1. Very stony areas deciduous sparse low woodland with upland tall grass. CAHP 4 3 Gentle slopes or slight depressions Springvale - shallow dark grey clay loam over soft limestone. Bloodwood-southern box low woodland (C. opaca, C. confertiflora) with Tippera tall grass. TTGP 5 5 Lower gentle slopes of depressions Cununurra - grey cracking clay. Trees absent on downs sparse low woodland (Bauhinia cunninghamii) with bluegrass tall grass (Dichanthium spp., Sorghum plumosum). FRIP 6 2 Stream channels Fringing communities. FRIP Image of Dinnabung land system frequently occurs as broad expanses of gentle slopes between the limestone hills of Tanmurra land system (foreground and background). Photo: Noel Schoknecht, DAFWA Djada land system (Dja), size: 4437km2, publication source: WKY Active floodplains with extensive back plains of cracking clays, grasslands and grassy woodlands. Location map showing coverage of Djada land system defined by black region. State land type: River plains with grassy woodlands and tussock grasslands. Geology: Quaternary alluvium. Geomorphology: Alluvial plains - active floodplains: extensive back plains of dark cracking clays with shallow linear depressions and deeper billabongs, traversed by minor channels; scalded, levee zones flanking meandering and anastomosing
channels; main gradients between 1 in 2000 and I in 4000 but up to 1 in 400 on tributary floodplains. Land management: Substantial parts of the system are subject to regular flooding which restricts access. Pastures are highly preferred by cattle and are prone to overuse and degradation. Levee crests and levee back slopes (units 2 & 3) are highly susceptible to erosion; control of grazing pressure is essential. Image of Levee backslopes of the Djada land system are subject to fairly regular flooding and support productive grassy woodlands with coolibah (Eucalytpus microtheca) and ghost gum (Corymbia bella). Photo: DAFWA Stylised plan diagram showing arrangement of land units for the Djada land system (numbers on diagram represent land units in table below) Table of Djada land system – land units. * Numbers in brackets refer to soil family or vegetation community/alliance in ‘General report on lands of the West Kimberley area, WA’ (Speck et al. 1970); + Pasture types described in Appendix 1; Note: Proportions and occurrence of pasture types within land units are subject to change over time due to invasion by native and introduced species, seasonal conditions, fire frequency and grazing management. area (%) Landforms Soils* Vegetation* Pasture type+ 1 5 Main channels: up to 800m wide and 12m deep. Channels no soils. Banks brownish loamy alluvial soils: Robinson family (21). Fringing forests and woodlands. E. camaldulensis - Terminalia platyphylla fringing communities (42, 43). XXNP 80% FRIP 20% 2 8 Levee crests: mainly up to 1.5m high and 400m wide, but attaining 800m inside meanders; bank slopes up to 1%. Mainly clayey alluvial soils: Fitzroy family (22). Open grassy woodland with scattered or patchy shrubs moderately dense, tall to medium-height grass layer, and patches of short annual grasses. Corymbia bella alliance (22a); locally 22b. Forbs seasonal. [Introduced buffel grass (Cenchrus ciliaris) now common]. FRGP 80% BUGP 20% 3 24 Levee backslopes: Brownish Very open grassy FRGP
up to 0.5% and 800m long, locally up to 3.4km long; broadly undulating with low rises up to 610m across and local slopes up to 1%: hummocky, scalded surfaces. juvenile cracking clays (16). woodland or grassland. Subject to degradation and scalding. Patchy, tall to medium-height grasses, short annual grasses, and forbs in season. Corymbia bella, E. microtheca, and Bauhinia cunninghamii alliances (20a, 20b, 21, 22a, 37a, 38c); and locally 48. Highest-rainfall parts also include 23, 24. [Introduced buffel grass (Cenchrus ciliaris) now common]. 90% BUGP 10% 4 46 Back plains: almost flat plains up 8km wide with marginal slopes up to 0.2%, including rises up to 1m high and 1.6km across with slopes up to 0.4%; sealed, hummocky surfaces with microrelief, and gilgais up to 1m deep locally. Mainly dark selfmulching clays with some dark brown clays: Cununurra (12) and Wonardo (14) families. Grasslands with scattered trees arid shrubs. Astrebla spp, and Chrysopogon spp. - Dichanthium fecundum communities (47, 48); locally 20b, 37b, 55. Also areas of annual grasses and forbs. MGAP 80% RAPP 20% 5 7 Depressions: up to 800m wide and 1m deep; hummocky, sealed surfaces. Grey crusty heavy clays Myroodah family (13). Variable, but commonly tall to medium-height perennial grasses. Chrysopogon spp. - Dichanthium fecundum and Chrysopogon spp. communities (48, 49). Locally annual grasses or forbs. RAPP 6 10 Minor channels and billabongs: channels up 60m wide and 4.5 m.deep, occurring singly or in zones up to 2.5km wide; billabongs up to 25m wide and 3.2km long, Brownish, massive, intractable, silty to heavy clay in (30). Fringing woodlands (20a, 20c, 21). FRIP
sandy slopes mainly less than 1% but with marginal slopes up to 5%; laterite exposures locally. with laterite horizon: Yabbagoddy family (1). Acacia shrubs and Triodia bitextura. Eucalyptus brevifolia community (1d). 2 47 Ridges: up to 150m high and 4.8km long; narrow, rocky crests and benched slopes up to 70%, locally vertical with basal scree slopes up to 35%; concave lower slopes up to 10% and 800m long, colluvial mantles and local outcrop. Much outcrop with shallow, micaceous sandy skeletal soils (24). Open woodland of small, stunted trees, moderately dense to sparse shrub layer and Triodia intermedia and T. inutilis, E. brevifolia alliance (1a, 1b). HSHP 3 33 Valley plains: up to 4.8km wide and 16km long, slopes mainly less than 0.5%; dissected up to 9m with local slopes up to 10%. Shallow brownish sands and loams over red clay commonly high in rock fragments: Moonah family (17). As for unit 2. HSPP 4 8 Alluvial drainage floors: up to 400m wide, gradients 1 in 100 to 1 in 500. Locally developed, commonly scalded areas of greyish to brownish sands and loams over tough clays: Hooper family (20). Open spinifex grassland with scattered low trees and shrubs. Triodia intermedia commonly (57). HSPP 5 10 Channels: up to 30m wide and 4.5m deep, ranging from hillslope channels, gradients up to 1 in 30 to main channels with gradients as low as 1 in 500. Channels bed-loads range from sand to boulders. Banks, probably brownish sandy and loamy alluvial soils: Small streams fringed by low trees and spinifex of adjacent community. E. brevifolia commonly (1a). Larger streams with fringing woodlands. E. camaldulensis - Terminalia platyphylla fringing HSPP 50% FRIP 50%