Soils on Older Consolidated Sediments

Orb - Ordovician Gently Dissected | Org - Ordovician Plain | Orr - Ordovician Hills (North) | Ors - Ordovician Steep Hills

Orb - Ordovician Gently Dissected

This unit represents 0.9% of the survey area and covers approximately 1.9 km². It is mainly part of the catchment to White Swan Reservoir in the western part of the Shire. The unit is mostly covered with a good stand of messmate and narrow-leafed stringybark but blue gum and broad-leafed peppermint are present. One of the major uses is protection of the Ballarat water supply

COMPONENT	1	2	3
Proportion %	10	85	5
CLIMATE (Average) Rainfall mm	750 - 780
*Temperature °C	Average annual 12⁰C
*Seasonal growth limitations	Temperature less than 10°C May - September
GEOLOGY Age, growth	Ordovician, slates and sandstones
TOPOGRAPHY Landscape	Slightly dissected plains
Elevation (range) m	421
Local relief (av.) m	10
Drainage pattern	Dendritic
Drainage density km/km²	3.9
Land form	Rolling plains
Position on land form	Crest	Long gentle slopes	Drainage line
Slope (av.) ,%, slope shape	1-2; Convex	2-7; Straight	1-2; Concave
NATIVE VEGETATION Structure	Woodland	Open forest
Dominant species	E. obliqua, E. radiata, E. dives	E. viminalis, E. obliqua, E. globulus	E. ovata, E. obliqua, E. globulus
SOIL Parent material	In-situ weathered rock	In-situ weathered rock	Alluvium, clays, silts sands and gravels
Description	Shallow stony red gradational soils	Mottled yellow, red gradational soils	Mottled yellow and red gradational soils
Surface texture	Gravelly loamLoamy clayClay loam
Permeability	High	Moderate-high	Moderate-low
Depth (av.) in	0.6	1	2
LAND USE	Forestry with some grazing
SOIL DETERIORATION Critical land features	Hard setting surfaces, dispersibility	Hard setting surfaces	Moderate dispersibility, poorly drained site, hard setting surfaces
Processes	Overland flow	Overland flow	Overland flow
Forms	Sheet and rill erosion, compaction	Sheet and rill erosion, gully erosion, compaction	Gully erosion

* Ballan figures

LAND UNIT: Ordovician hills (moist)

COMPONENT: 1-Crests – Shallow stony gradational soils

MAP SYMBOL: Orb 1

CAPABILITY OF THE LAND TO SUPPORT VARIOUS ACTIVITIES			CAPABILITY OF THE LAND TO SUPPORT SUBDIVISION
ACTIVITY	RATING	MAJOR LIMITING FEATURES OF THE LAND	SUBDIVISION TYPE	RATING	MAJOR LIMITING ACTIVITIES
Building houses	Fair	Depth to rock (moderate hardness); stoniness.	Urban (sewered)	Poor	Shallow excavations; (otherwise-fair: building houses; secondary roads).
Absorption fields	Poor	Too stony; depth of soil.	Small Farmlets 4 ha	Poor	Small farm dams; absorption fields - effluent; (otherwise fair: access tracks; gravel roads; building houses).
Secondary roads	Fair	Depth to rook (moderate hardness); stoniness.	Large Farmlets 16 ha	Poor	Small farm dams; absorption fields - effluent; (otherwise-fair: access tracks; building houses).
Gravel roads	Fair	Stoniness	Bush Blocks 4 ha.	Poor	Absorption fields - effluent; clearing for house sites and access tracks.
Access tracks	Fair	Stoniness; erosion of surface.
Shallow excavations	Poor	Depth to rock (moderate hardness); stoniness.
Small farm dams	Poor	Depth to rock; stoniness; catchment requirements.
Sewerage lagoons	Poor	Depth to rook.
Topsoil - Quality	Poor	Stoniness.
- Removal	Very poor	Very thin layer; stones.
- Resowing	Poor	Infertile shallow subsoil; stoniness; slope.
Sand - Quality	Very poor	No sand.
- Operation
Gravel - Quality	Fair	Variable: clay content; stoniness.
- Operation	Fair to poor	Erodible soils; slope.
Grazing	Poor	Shallow stony soils of low moisture holding capacity and low fertility.
Cultivation	Very poor	Very shallow, stony soils - not cultivated.
Clearing	Poor	Slow revegetation - sheet erosion

EFFECT OF SUBDIVISION OF THE LAND ON TOWN WATER SUPPLY
URBAN:	Due to the poor soils, it will be difficult to quickly re-establish vegetation to protect earthworks. There will be a considerable risk of silt loss during development especially if clearing is required.
FARMLET:	Erosion of gravel roads and tracks will be the main source of turbidity and siltation from farmlet subdivisions. Note: This unit is normally uncleared and if cleared, supports low stocking rates. Higher rates or badly managed stock can lead to overgrazing and therefore sheet erosion. Failure of septic absorption fields because of the shallow stony soils and steep slopes will be a risk. Percolation rates may be very rapid, but the lack of soil depth and high rock fragment content will hinder soil treatment of effluent. If this component is included in a subdivision, it would be better if it formed part of a large block which also contained areas of better land.
BUSH BLOCK:	As for farmlets, effluent absorption and erosion of roads and tracks will be the main continuing hazards. However, clearing for the construction of roads, tracks and house sites will be a risk during the development stage. The steep slopes and shallow stony soils will make safe planning and construction extremely difficult.

LAND UNIT: Ordovician hills (moist)

COMPONENT: 2 - Long gentle slopes-mottled yellow gradational soil

MAP SYMBOL: Orb 2

CAPABILITY OF THE LAND TO SUPPORT VARIOUS ACTIVITIES			CAPABILITY OF THE LAND TO SUPPORT SUBDIVISION
ACTIVITY	RATING	MAJOR LIMITING FEATURES OF THE LAND	SUBDIVISION TYPE	RATING	MAJOR LIMITING ACTIVITIES
Building houses	0-15% Fair	Erosion during construction; dispersible clay; low to moderate shrink-swell.	Urban (sewered)	0-15% Fair	Building houses; secondary roads.
Absorption fields	Fair	Variable percolation rates; imperfect soil drainage; perched temporary watertables.	Small Farmlets 4 ha	Fair	Absorption fields-effluent; building houses; gravel roads; access tracks; clearing- if required).
Secondary roads	0-12% Fair 12-20% Poor	Risk of erosion during construction. Slope for construction.	Large Farmlets	Fair	Absorption fields-effluent; building houses; access tracks; (and clearing if required).
Gravel roads	Fair to poor	Risk of erosion to surface, batters and drains.	Bush Blocks 4 ha.	Fair	Absorption fields-effluent; building houses; gravel roads; access tracks; clearing for construction.
Access tracks	Fair to poor	Risk of erosion to surface and drains
Shallow excavations	0-8% Good 8-15% Fair	Slope - machinery operation.
Small farm dams	Good
Sewerage lagoons	2-8% Fair 8-15% Poor	Slope for construction
Topsoil - Quality	Fair	Hard setting.
- Removal	Poor	Thin layer.
- Resowing	^poor	Infertile, easily eroded sub-soil.
Sand - Quality	Very poor	No sand.
- Operation
Gravel - Quality	Poor	Gravel deposits rare.
- Operation	Fair	Slope - erosion risk.
Grazing	Fair	Hard-setting structureless topsoil; impermeable clay.
Cultivation	Poor	Slope; hard setting structureless topsoil.
Clearing	Fair	Silt loss prior to pasture establishment.

EFFECT OF SUBDIVISION OF THE LAND ON TOWN WATER SUPPLY
URBAN:	Although much of this land is rated fair for urban development, erosion and silt loss during development will be a considerable hazard to the water quality. The hazard will be increased if clearing is required (much of the land is forested). Land disturbance guidelines should be observed.
FARMLETS:	Erosion of batters, drains and surfaces of gravel roads; access tracks and construction sites will be a major source of dispersible clay and silt. Correct planning and construction will be required to minimise this hazard. High silt loss can be expected if clearing is required. Also the impermeable clay often results in perched watertables. Effluent disposal by absorption fields is likely to cause problems, especially on the lower slopes near drainage lines.
BUSH BLOCK:	As for farmlets, erosion of roads, tracks and cleared areas is a potential problem. NOTE: Soil drainage under forest is generally somewhat better than for cleared areas. Absorption fields will probably function a little better.

LAND UNIT: Ordovician hills (moist)

COMPONENT: 3 – Drainage lines-mottled yellow/red gradational soil

MAP SYMBOL: Orb 3

CAPABILITY OF THE LAND TO SUPPORT VARIOUS ACTIVITIES			CAPABILITY OF THE LAND TO SUPPORT SUBDIVISION
ACTIVITY	RATING	MAJOR LIMITING FEATURES OF THE LAND	SUBDIVISION TYPE	RATING	MAJOR LIMITING ACTIVITIES
Building houses	Poor to very poor	Soil drainage; surface flows (very poor in flood risk areas).	Urban (sewered)	Poor to very poor	Building houses; secondary roads; shallow excavations.
Absorption fields	Very poor	Soil drainage - seasonal and permanent watertables; percolation rate.	Small Farmlets 4 ha	Very poor	Soil absorption fields - effluent; access tracks (otherwise poor: building houses; gravel roads).
Secondary roads	Poor	Soil drainage; some flood risk; surface flows; erosion during construction.	Large Farmlets	Very poor	Soil absorption fields - effluent; access tracks (otherwise-poor: building houses).
Gravel roads	Poor	Soil drainage; surface flows; erosion during construction; erosion of drains and surface.	Bush Blocks 4 ha	Very poor	Soil absorption fields - effluent; access tracks (otherwise-poor: building houses; gravel roads).
Access tracks	Very poor	Soil drainage; surface flows; erosion of surface and drains.
Shallow excavations	Poor	Soil drainage.
Small farm dams	Fair to good	Variable material for embankment.
Sewerage lagoons	Poor	Flood prone; proximity to watercourse.
Topsoil - Quality	Good	Thin layer.
- Removal	Fair	Surface flows.
- Resowing	Poor	Severe erosion risk.
Sand - Quality	Poor	Quality variable.
- Operation	Poor	Poor drainage; surface flows; erosion risk.
Gravel - Quality	Poor	Quality variable.
- Operation	Poor	Poor drainage; surface flows; erosion risk.
Grazing	Fair	Soil drainage; pugging of soil; possible gully erosion.
Cultivation	Very poor	Surface flow; fallow wash - rilling; sheet and gully erosion.
Clearing	Poor	Surface flow; topsoil wash prior to pasture establishment.

EFFECT OF SUBDIVISION OF THE LAND ON TOWN WATER SUPPLY
URBAN:	Due to the poor drainage and risk of high velocity floods, much of the land is not capable of supporting urban subdivision without extensive drainage works. However, any development within these drainage lines is likely to contribute significantly to turbidity and silt loads, particularly during construction.
FARMLET:	Although this unit may be included as part of a farmlet block, it is essential that buildings, access and effluent disposal should be excluded from it. Clearing will involve a serious risk of erosion.
BUSH BLOCK:	As with farmlets, this unit may be included as part of a bush block, as long as housing access and effluent disposal areas are excluded from this unit.

Orr - Ordovician Hills (North)

This unit represents 18.5% of the survey area and covers a total area of 38.2 km². It is predominantly forested and in public ownership in the north eastern part of the Shire. Part of the unit has been cleared and is used for grazing with occasional crops as part of the pasture improvement. A large part of the area has been converted to softwood plantation. Most of the catchment to Korweinguboora Reservoir is in this unit and careful management of the land is required to protect the water supply

COMPONENT	1	2	3	4
Proportion %	20	15	60	5
CLIMATE (Average) Rainfall mm	760 - 1000
*Temperature °C	Average annual 12^oC
*Seasonal growth limitations	Temperature less than 10⁰C May - September
GEOLOGY Age, growth	Ordovician, slates and sandstones and Quaternary basalt
TOPOGRAPHY Landscape	Hills at northern end of Shire
Elevation (range) m	670
Local relief (av.) m	45
Drainage pattern	Dendritic
Drainage density km/km²	5.9
Land form	Hills
Position on land form	Crest & steep slopes	Slopes with deep soil	Slopes with shallow soil	Drainage line
Slope (av.) ,%, slope shape	5-20 ; Convex	3-8 ; Straight	3-8 ; Straight	1-4 ; Concave
NATIVE VEGETATION Structure	Open forest
Dominant species	E. radiata, E. dives, E. rubida, E. obliqua	E. viminalis, E. obliqua, E. radiata, E. rubida	E. obliqua, E. radiata, E. rubida, E. dives, E. viminalis	E. ovata,. E. obliqua, E. rubida, E. radiata
SOIL Parent material	In-situ weathered rock	In-situ weathered rock	In-situ weathered rock	Alluvium, colluvium clay, silt, sand and gravel
Description	Shallow stony brown gradational soil	Red gradational soil, fine structure	Yellow gradational soil, fine structure	Brown gradational soil
Surface texture	Gravelly loam	Clay loam	Clay loam	Clay loam
Permeability	High	High	Moderate-high	Moderate
Depth (av.) in	1.5	2	1	2
LAND USE	Soft wood plantations, some grazing, cropping
SOIL DETERIORATION Critical land features	Steep slopes	Slopes	Slopes	Moderate permeability, dispersibility
Processes	Overland flow, leaching	Overland flow, leaching	Overland flow, leaching	Overland flow, subsurface, water logging
Forms	Sheet & rill erosion, nutrient decline	Sheet erosion, nutrient decline	Sheet & rill erosion, nutrient decline	Gully erosion, compaction

* Ballan figures

LAND UNIT: Ordovician hills (north)

COMPONENT: 1 – Crests – shallow stony gradational soils

MAP SYMBOL: Orr 1

CAPABILITY OF THE LAND TO SUPPORT VARIOUS ACTIVITIES			CAPABILITY OF THE LAND TO SUPPORT SUBDIVISION
ACTIVITY	RATING	MAJOR LIMITING FEATURES OF THE LAND	SUBDIVISION TYPE	RATING	MAJOR LIMITING ACTIVITIES
Building houses	Poor	Slope; depth to rock (moderate hardness).	Urban (sewered)	Poor	Building houses; secondary roads; shallow excavations.
Absorption fields	Poor	Slope; depth to rook; stoniness.	Small Farmlets 4 ha	Very poor	Small farm dams; (otherwise-poor: absorption fields - effluent; building houses; gravel roads; access tracks; clearing; resowing).
Secondary roads	Poor	Slope; depth to rook (moderate hardness).	Large Farmlets 16 ha	Very poor	Small farm dams; (otherwise-poor: absorption fields - effluent; houses; access tracks; clearing resowing).
Gravel roads	Poor	Slope; depth to rook; erosion of drains and batters.	Bush Blocks 4 ha.	Poor	Absorption fields - effluent; building houses; gravel roads; access tracks; clearing (for house sites and access).
Access tracks	Poor	Slope; depth to rock; stoniness; erosion of surface and batters.
Shallow excavations	Poor	Slope; depth to rook (moderate hardness).
Small farm dams	Very poor	Slope; depth to rook.
Sewerage lagoons	Very poor	Slope; depth to rock
Topsoil - Quality	Poor	Very stony soil.
- Removal	Poor	Thin layer.
- Resowing	Poor	Slope; poor quality shallow soils-erosion.
Sand - Quality	Very poor	No sand.
- Operation
Gravel - Quality	Variable	Slope; poor quality shallow soils-erosion.
- Operation	Poor
Grazing	Fair	Shallow stony soil; low fertility and moisture holding capacity; poor pastures.
Cultivation	Very poor	Shallow stony soils.
Clearing	Poor	Shallow stony soil; low fertility; slow pasture regeneration; sheet erosion.

EFFECT OF SUBDIVISION OF THE LAND ON TOWN WATER SUPPLY
URBAN:	Due to the poor soils, it will be difficult to quickly re-establish vegetation to protect earthworks. There will be a considerable risk of silt loss during development especially if clearing is required.
FARMLET:	Erosion of gravel roads and tracks will be the main source of turbidity and siltation from farmlet subdivisions. Note: This component is normally uncleared and if cleared, supports low stocking rates. Higher rates or badly managed stock can lead to overgrazing and therefore sheet erosion. Failure of septic absorption fields because of the shallow stony soils and steep slopes will be a risk. Percolation rates maybe very rapid, but the lack of soil depth and high rock fragment content will hinder soil treatment of effluent. If this component is included in a subdivision, it would be better if it formed part of a large block which also contained areas of better land.
BUSH BLOCK:	As for farmlets, effluent absorption and erosion of roads and tracks will be the main continuing hazards. However, clearing for the construction of roads, tracks and house sites will be a risk during the development stage. The steep slopes and shallow stony soils will make safe planning and construction extremely difficult.

LAND UNIT: Ordovician hills (north)

COMPONENT: 2 – Slopes – deep red gradational soils

MAP SYMBOL: Orr 2

CAPABILITY OF THE LAND TO SUPPORT VARIOUS ACTIVITIES			CAPABILITY OF THE LAND TO SUPPORT SUBDIVISION
ACTIVITY	RATING	MAJOR LIMITING FEATURES OF THE LAND	SUBDIVISION TYPE	RATING	MAJOR LIMITING ACTIVITIES
Building houses	Good		Urban (sewered)	Good
Absorption fields	Good		Small Farmlets 4 ha	Fair	Small farm dams.
Secondary roads	Good		Large Farmlets 16 ha	Fair	Small farm dams.
Gravel roads	Good		Bush Blocks 4 ha.	Good
Access tracks	Good
Shallow excavations	Good
Small farm dams	Fair to poor	Percolates rapidly.
Sewerage lagoons	Poor	Slope; percolates too rapidly
Topsoil - Quality	Fair	Good
- Removal	Poor	Thin layer.
- Resowing	Fair	Slope, infertile subsoil-sheet erosion
Sand - Quality	Very poor	No sand
- Operation
Gravel - Quality	Poor	Gravelly areas are rare.
- Operation	Good
Grazing	Very good
Cultivation	Good to fair	Slope-sheet and rill erosion, fertilizer requirements.
Clearing	Good	Slope-erosion during pasture establishment.

EFFECT OF SUBDIVISION OF THE LAND ON TOWN WATER SUPPLY
URBAN FARMLET and BUSH BLOCK:	The main limitation of this unit is that it generally occurs in small areas each of only a few hectares or less) associated with component 3 (yellow gradational soils). Bore holes are required to differentiate these two components. The yellow soils are poorer than the red gradational soils, and are far more erosion prone when exposed. They are also far more common (the ratio of yellow to red soils is approximately 4:1 although this varies). Thus a subdivision is likely to contain both soil types, with the yellow soil being far more common. Therefore, the limiting features of component 3 must be considered when planning a subdivision. On individual blocks, the red soil will be far better than the yellow for effluent absorption and worse than the yellow for dams because of its higher percolation rate.

LAND UNIT: Ordovician hills (north)

COMPONENT: 3 – Slopes – Mottled yellow gradational soil

MAP SYMBOL: Orr 3

CAPABILITY OF THE LAND TO SUPPORT VARIOUS ACTIVITIES			CAPABILITY OF THE LAND TO SUPPORT SUBDIVISION
ACTIVITY	RATING	MAJOR LIMITING FEATURES OF THE LAND	SUBDIVISION TYPE	RATING	MAJOR LIMITING ACTIVITIES
Building houses	0-15% Fair 15+% Poor	Erosion during construction, dispersible clay, low to moderate shrink-swell.	Urban (sewered)	Fair to poor	Building houses; secondary roads.
Absorption fields	Fair	Variable percolation rate; imperfect drainagetemporary watertables, esp. on cleared land.	Small Farmlets 4 ha	Fair	Absorption fields-effluent; building houses; gravel roads; access tracks; clearing - if required
Secondary roads	0-12% Fair 12+% Poor	Dispersible clay; erosion during construction.	Large Farmlets 16 ha	Fair	Absorption fields-effluent; building houses; access tracks; (and clearing if required).
Gravel roads	Fair to poor	Risk of erosion of batters and drains.	Bush Blocks 4 ha	Fair	Absorption fields-effluent; building houses; gravel roads; access tracks; clearing for construction.
Access tracks	Fair to poor	Risk of erosion of surface and drains.
Shallow excavations	Good	Seasonal drainage problems.
Small farm dams	Good
Sewerage lagoons	Fair	Slope-construction.
Topsoil - Quality	Fair	Too clayey, hard setting.
- Removal	Poor	Thin layer.
- Resowing	Poor	Infertile, easily eroded subsoil layers.
Sand - Quality	Very poor	No sand.
- Operation
Gravel - Quality	Poor	Gravel deposits rare.
- Operation	Fair	Erosion risk.
Grazing	Good to fair	Hard setting structureless topsoil, impermeable clay, overgrazing will cause a high risk of erosion.
Cultivation	Poor	Hard setting structureless topsoil, impermeable clay, high risk of erosion.
Clearing	Fair	Slow pasture establishment, shallow, low fertility topsoil, erosion prior to pasture establishment.

EFFECT OF SUBDIVISION OF THE LAND ON TOWN WATER SUPPLY
URBAN:	Although much of this land is rated fair for urban development, erosion of the Boils will be a considerable hazard to water quality during development and construction. The hazard will be increased if clearing is required (many areas of this land system remain under forest). Land disturbance guidelines should be observed to minimise pollution by erosion of construction sites.
FARMLETS:	Erosion of batters, drains and surfaces of gravel roads and tracks will be a major source of silt and dispersible clay. Correct planning and construction would be required to minimize this hazard. Many areas would require clearing for farmlets. High silt loads can be expected prior to pasture establishment. Also the impermeable clay commonly causes perched watertables especially in cleared land. Effluent disposal by soil absorption will cause problems especially on lower slopes and near drainage lines.
BUSH BLOCKS:	As for farmlets, erosion of roads and tracks is a potential problem. Also, clearing for access and building sites will be additional hazard. NOTE: soil drainage under forest is generally somewhat better than for cleared areas, especially on upper and mid slopes.

LAND UNIT: Ordovician hills (north)

COMPONENT: 4 – Slopes – Drainage line – brown gradational soils

MAP SYMBOL: Orr 4

CAPABILITY OF THE LAND TO SUPPORT VARIOUS ACTIVITIES			CAPABILITY OF THE LAND TO SUPPORT SUBDIVISION
ACTIVITY	RATING	MAJOR LIMITING FEATURES OF THE LAND	SUBDIVISION TYPE	RATING	MAJOR LIMITING ACTIVITIES
Building houses	Poor to very poor	Soil drainage; surface flows (very poor in flood risk areas).	Urban (sewered)	Poor to very poor	Building houses; secondary roads; shallow excavations.
Absorption fields	Very poor	Soil drainage-seasonal and permanent watertables; percolation rate.	Small Farmlets 4 ha	Very poor	Absorption fields - effluent; access tracks; gravel roads; building houses.
Secondary roads	Poor	Soil drainage; some flood risk; surface flows; erosion during construction.	Large Farmlets 16 ha	Very poor	Absorption fields - effluent, access tracks; building houses.
Gravel roads	Poor to very poor	Soil drainage; surface flows; erosion during construction; erosion of drains and surface.	Bush Blocks 4 ha.	Very poor	Absorption fields - effluent; access tracks; gravel roads; building houses.
Access tracks	Very poor	Soil drainage; surface flows; erosion or surface and drains.
Shallow excavations	Poor	Soil drainage.
Small farm dams	Fair to good	Variable material for embankment.
Sewerage lagoons	Poor	Flood prone; proximity to watercourse.
Topsoil - Quality	Good	Thin layer.
- Removal	Fair
- Resowing	Poor	Surface flows; impermeable poor subsoil; severe erosion risk.
Sand - Quality	Poor	Quality variable.
- Operation	Poor	Poor drainage; overland flows; severe erosion.
Gravel - Quality	Poor	Quality-variable.
- Operation	Poor	Poor drainage; overland flows; severe erosion.
Grazing	Fair	Soil drainage; pugging of soil; possible gully erosion (some areas flood).
Cultivation	Very poor	Surface flows; fallow wash - rilling; sheet and gully erosion.
Clearing	Poor	Surface flows; topsoil wash prior to pasture establishment.

EFFECT OF SUBDIVISION OF THE LAND ON TOWN WATER SUPPLY
URBAN:	Due to the poor drainage and risk of high velocity floods, much of the land is not capable of supporting urban subdivision without extensive drainage works. However, any development within these drainage lines is likely to contribute significantly to turbidity and silt loads, particularly during construction.
FARMLET:	Although this unit may be included as part of farmlet blocks, it is essential that buildings, access and effluent disposal should be excluded from this unit. Clearing will involve a serious risk of erosion.
BUSH BLOCK:	As with farmlets, this unit may be included as part of abash block, as long as housing access and effluent disposal areas are excluded from this unit.

Ors - Ordovician Steep Hills

This unit represents 7.9% of the survey area or 16.4 km2 and contains the most hazardous land in the Bungaree Shire. Most of the steepest hills have fortunately been left forested which is the most suitable land use for this unit. Some of the gentler parts have been cleared for grazing. The unit can be distinguished from other Ordovician units by the characteristic steep slopes and soils not _influence by volcanic dykes

COMPONENT	1	2	3	4
Proportion %				45
CLIMATE (Average) Rainfall mm	660 - 710
*Temperature °C	Average annual 12^oC.
*Seasonal growth limitations	Temperature less them 10 C May - September
GEOLOGY Age, growth	Ordovician; slates and sandstones
TOPOGRAPHY Landscape	Hilly areas throughout the Shire
Elevation (range) m	425
Local relief (av.) m	65
Drainage pattern	Dendritic
Drainage density km/km²	7.6
Land form	Hill
Position on land form	Southern slope	Northern slope	Drainage line	Crest
Slope (av.) ,%, slope shape	15 ; Straight	15 ; Straight	3 ; Concave	3 ; Convex
NATIVE VEGETATION Structure	Tall open forest	Open forest
Dominant species	E. obliqua, E. ovata, E. radiata, E. viminalis	E. dives, E. obliqua, E. viminalis, E. radiata	E. radiata, E. viminalis E. obliqua	E. obliqua, E. dives, E. viminalis, B. radiata
SOIL Parent material	In-situ weathered rock	In-situ weathered rock	Alluvium, clay, silt, sand, gravel	In-situ weathered rock
Description	Mottled yellow and red gradational soil, fine structure	Mottled yellow and red gradational soil, fine structure	Black gradational soil, variable)	Shallow stony red gradational soil
Surface texture	Fine sandy loam	Fine sandy loam	Clay loam	Gravelly loam
Permeability	High	High	Moderate-low	High
Depth (av.) in	1	1		0.5
LAND USE	Mainly forestry, grazing
SOIL DETERIORATION Critical land features	Steep slopes, hard setting surfaces	Steep slopes, hard setting surfaces	Moderate permeability, hard setting surfaces, dispersibility	Moderate elopes, hard setting surfaces
Processes	Overland flow	Overland flow	Overland flow, subsurface flow, waterlogging	Overland flow
Forms	Sheet and rill erosion	Sheet and rill erosion, compaction	Gully erosion, compaction	Sheet and rill erosion compaction

* Ballan figures

LAND UNIT: Ordovician steep hills

COMPONENT: 1 – Southern slopes – mottled red/yellow gradational soils

MAP SYMBOL: Ors 1

CAPABILITY OF THE LAND TO SUPPORT VARIOUS ACTIVITIES			CAPABILITY OF THE LAND TO SUPPORT SUBDIVISION
ACTIVITY	RATING	MAJOR LIMITING FEATURES OF THE LAND	SUBDIVISION TYPE	RATING	MAJOR LIMITING ACTIVITIES
Building houses	0-15% Fair 15+% Poor	Slope and erodible soils-erosion during construction.	Urban (sewered)	0-15% Fair 15+% Poor	Building houses; secondary roads (development stage).
Absorption fields	Poor	Slow percolation rate (variable); slope affecting layout and operation.	Small Farmlets 4 ha	Poor	Absorption fields - effluent; small farm dams; access tracks; gravel roads.
Secondary roads	0-15% Fair	Slope & erodible soils-erosion during construction.	Large Farmlets	Poor	Effluent absorption; farm tracks; (clearing).
Gravel roads	Poor	Erosion of table drains and batters due to the slope and erodible clay.	Bush Blocks 4 ha.	Poor	Absorption fields -effluent; gravel roads; access tracks; clearing for house sites and access.
Access tracks	Poor	Erosion of drains; batters and surfaces due to elope and erodible clay.
Shallow excavations	Fair	Depth to rock (soft to moderately hard).
Small farm dams	0-10%Fair 10+%	Slope-construction; depth of material. Slope.
Sewerage lagoons	Poor	Slope - construction.
Topsoil - Quality	Fair	Structureless; hard setting
- Removal	Poor	Thin layer
- Resowing	Very poor	Slope; infertile erodible sub-soil
Sand - Quality	Very poor	No sand
- Operation
Gravel - Quality	Poor	Gravel deposits rare
- Operation	Poor	Slope - erosion risk
Grazing	Good to fair	Soil erodibility; low fertility; and poor structure. Overgrazing causes sheet erosion. Slope; poorly structured, erodible topsoil.
Cultivation	Very poor	Cultivated soil can be easily eroded on these slopes.
Clearing	Poor	Slope-erodibility of the soil and difficulty of establishing pasture.

EFFECT OF SUBDIVISION OF THE LAND ON TOWN WATER SUPPLY
URBAN:	Unless special management techniques are employed, dispersible clay and silt from development sites will severely affect the water supply.
FARMLETS:	Percolation tests indicate a large variability for the success of effluent absorption in these soils. The average rate of absorption is slow. This together with the gradient of the land increases the risk of pollution from failing absorption trenches. Also, silt and dispersible clay will be common pollutants due to the elopes and the erodible soils. Gravel roads, tracks and existing erosion are likely to be the main sources of these pollutants although overgrazing may contribute. Clearing will be another potential source of sediment due to difficulties in establishing good pasture cover quickly - Note: large areas still remain forested because of the slopes, hazard of erosion and poor pasture production.
BUSH BLOCKS:	As above, effluent disposal, gravel roads and tracks will be main sources of pollution. Clearing for house sites and access will be an additional source of sediment unless correctly managed.

LAND UNIT: Ordovician steep hills

COMPONENT: 2 – Northern slopes – mottled yellow gradational soils

MAP SYMBOL: Ors 2

CAPABILITY OF THE LAND TO SUPPORT VARIOUS ACTIVITIES			CAPABILITY OF THE LAND TO SUPPORT SUBDIVISION
ACTIVITY	RATING	MAJOR LIMITING FEATURES OF THE LAND	SUBDIVISION TYPE	RATING	MAJOR LIMITING ACTIVITIES
Building houses	0-15% Fair 15+% Poor	Slope and erodible soils - erosion during construction.	Urban (sewered)	0-15% Fair 15+% Poor	Building houses; secondary roads (development stage).
Absorption fields	Poor	Slow percolation rate (variable); slope affecting layout and operation.	Small Farmlets 4 ha	Poor	Absorption fields-effluent; small farm dams; access tracks; gravel roads; (clearing - very poor).
Secondary roads	0-15% Fair 15+% Poor	Slope & erodible soils-erosion at construction.	Large Farmlets 16 ha	Poor	Absorption fields-effluent; small farm dams; access tracks; (clearing -^.very poor).
Gravel roads	Poor	Erosion of table drains and batters due to the slope & erodible clay.	Bush Blocks 4 ha.	Poor	Absorption fields-effluent; gravel roads; access tracks; clearing for house sites and access.
Access tracks	Poor	Erosion of drains, batters & surface due to slope and erodible clay.
Shallow excavations	Fair	Depth to rook (soft to moderately hard).
Small farm dams	0-10% Fair 10+% Poor	Slope - construction; depth of material. Slope
Sewerage lagoons	Poor	Slope - construction
Topsoil - Quality	Fair	Structureless; hard setting
- Removal	Poor	Thin layer
- Resowing	Very poor	Slope; infertile erodible sub-soil
Sand - Quality	Very poor	No sand
- Operation
Gravel - Quality	Poor	Gravel deposits rare
- Operation	Poor	Slope - erosion risk
Grazing	Fair	Soil erodibility; low fertility; and poor structure. Overgrazing causes sheet erosion.
Cultivation	Very poor	Slope; poorly structured; erodible topsoil. Cultivated soil can be easily eroded on these slopes.
Clearing	Very poor	Slope; erodibility of the soil and difficulty of establishing pasture.

EFFECT OF SUBDIVISION OF THE LAND ON TOWN WATER SUPPLY
URBAN:	Unless special management techniques are employed, dispersible clay and silt from development sites will severely affect the water supply.
FARMLETS:	Percolation tests indicate a large variability for the success of effluent absorption in these soils. The average rate of absorption is slow. This together with the gradient of the land increases the risk of pollution from failing absorption trenches. Also, silt and dispersible clay are common pollutants due to the elopes and the erodible soils. Gravel roads, tracks and existing erosion are likely to be the main sources of these pollutants although overgrazing will contribute. Clearing will be another major potential source of sediment due to difficulties in establishing good pasture cover quickly. Soils are poorer than those on the southern slopes (component 1).
BUSH BLOCKS:	As above, effluent disposal, gravel roads and tracks will be the main sources of pollution. Clearing for house sites and access will be an additional source of sediment unless correctly managed.

LAND UNIT: Ordovician steep hills

COMPONENT: 3 – Drainage line – black gradational soils (variable)

MAP SYMBOL: 3

CAPABILITY OF THE LAND TO SUPPORT VARIOUS ACTIVITIES			CAPABILITY OF THE LAND TO SUPPORT SUBDIVISION
ACTIVITY	RATING	MAJOR LIMITING FEATURES OF THE LAND	SUBDIVISION TYPE	RATING	MAJOR LIMITING ACTIVITIES
Building houses	Poor to very poor	Soil drainage; surface flows (very poor in flood risk areas).	Urban (sewered)	Poor to very poor	Building houses; secondary roads; shallow excavations.
Absorption fields	Very poor	Soil drainage - seasonal and permanent watertables; percolation rate.	Small Farmlets 4 ha	Very poor	Absorption fields-effluent; access tracks; (otherwise poor: house foundations; roads)
Secondary roads	Poor	Soil drainage; some flood risk; Surface flows; erosion during construction.	Large Farmlets 16 ha	Very poor	Absorption fields - effluent; access tracks (otherwise - poor: house foundations; roads
Gravel roads	Poor	Soil drainage; surface flow; erosion during construction; erosion of drains and surface.	Bush Blocks 4 ha.	Very poor	Absorption fields - effluent; access tracks (otherwise-poor: house foundations; roads)
Access tracks	Very poor	Soil drainage; surface flow; erosion of surface and drains.
Shallow excavations	Poor	Soil drainage.
Small farm dams	Fair to good	Variable material for embankment
Sewerage lagoons	Poor	Flood prone; proximity to watercourse.
Topsoil - Quality	Good	Thin layer.
- Removal	Fair	Surface flows.
- Resowing	Poor	Infertile sub-soil; severe erosion.
Sand - Quality	Variable
- Operation	Poor	Poor drainage; surface flows; severe erosion risk.
Gravel - Quality	Variable	Poor drainage; surface flows; severe erosion risk.
- Operation
Grazing	Fair	Soil drainage; pugging of soil; possible gully erosion.
Cultivation	Very poor	Surface flow; fallow wash - rilling; sheet and gully erosion.
Clearing	Very poor	Surface flow; topsoil wash prior to pasture establishment.

EFFECT OF SUBDIVISION OF THE LAND ON TOWN WATER SUPPLY
URBAN:	Due to the poor drainage and risk of high velocity floods, much of the land is not capable of supporting urban subdivision without extensive drainage works. However, any development within these drainage lines is likely to contribute significantly to turbidity and silt loads, particularly during construction.
FARMLET:	Although this unit may be included as part of farmlet blocks, it is essential that buildings, access and effluent disposal should be excluded from this unit. Clearing will involve a serious risk of erosion.
BUSH BLOCK:	As with farmlets, this unit may be included as part of bush blocks as long as housing access and effluent disposal areas are excluded from this unit.

LAND UNIT: Ordovician steep hills

COMPONENT: 4 – Crests – Shallow stony red gradational soils

MAP SYMBOL: Ors 4

CAPABILITY OF THE LAND TO SUPPORT VARIOUS ACTIVITIES			CAPABILITY OF THE LAND TO SUPPORT SUBDIVISION
ACTIVITY	RATING	MAJOR LIMITING FEATURES OF THE LAND	SUBDIVISION TYPE	RATING	MAJOR LIMITING ACTIVITIES
Building houses	Fair	Depth to rock (moderate hardness); stoniness.	Urban (sewered)	Poor	Shallow excavations (otherwise - fair: building houses; secondary roads)
Absorption fields	Poor	Too stony; shallow soil.	Small Farmlets 4 ha	Poor	Small farm dams; grazing; clearing; absorption fields - effluent; (otherwise-fair: building houses: gravel roads; access tracks)
Secondary roads	Fair	Depth to rook (moderate hardness); stoniness.	Large Farmlets 16 ha	Poor	Small farm dams: grazing; clearing; absorption fields - effluent: (otherwise - fair: building houses; access tracks).
Gravel roads	Fair	Stoniness	Bush Blocks 4 ha.	Poor	Effluent absorption; clearing for house sites; access tracks.
Access tracks	Fair	Stoniness; erosion of surface.
Shallow excavations	Poor	Depth to rock (moderate hardness)_; stoniness.
Small farm dams	Poor	Depth to rock; stoniness; catchment requirements
Sewerage lagoons	Poor	Depth to rook
Topsoil - Quality	Poor	Stoniness
- Removal	Very poor	Thin stony layer
- Resowing	Very poor	Depth to rook; infertile stony sub-soil
Sand - Quality	Very poor	No sand
- Operation
Gravel - Quality	Fair	Variable quality; clay content; stoniness
- Operation	Fair	Erodible soils; slope
Grazing	Poor	Shallow stony soils of low moisture holding capacity and low fertility
Cultivation	Very poor	Very shallow; stony soils - not cultivated
Clearing	Very poor	Very slow revegetation - sheet erosion; very poor pasture production.

EFFECT OF SUBDIVISION OF THE LAND ON TOWN WATER SUPPLY
URBAN:	Due to the poor soils and dispersible clays it will be difficult to quickly re-establish vegetation to protect earthworks. There will be a considerable risk of silt loss during development.
FARMLET:	Failure of septic absorption fields because of the shallow stony soils will be a hazard. Percolation rates maybe very rapid, but the lack of soil depth and high rock fragment content will hinder soil treatment of effluent. Erosion of gravel roads and tracks will be the main source of turbidity and siltation from farmlet subdivisions. Note: this unit is normally uncleared and if cleared supports low stocking rates. Excess or badly managed stock can lead to overgrazing and therefore sheet erosion. Clearing will involve a serious risk of erosion-large areas remain uncleared because of poor pasture production and erosion risk.
BUSH BLOCK:	As for farmlets, effluent absorption and erosion of reads and tracks will be the main continuing hazards. However, clearing for the construction of roads, tracks and house sites will be a very serious risk during the development stage. Bush block subdivision would require special planning and management to minimise pollution of the water supply.

Org - Ordovician Plain

The balance of the Ordovician material falls into a slightly dissected plain mainly in the northern parts of the Shire. The unit represents 17.7% of the survey area and covers 36.5 km². It is mainly used for grazing although increasingly used for cereal cropping. Parts of this unit falling within the Ballarat water supply catchments are in public ownership and forested with pine plantations.

COMPONENT	1	2	3
Proportion %	10	85	5
CLIMATE (Average) Rainfall mm	30 - 760
*Temperature °C	Average annual 12°C
*Seasonal growth limitations	Temperature less than 1000 May - September
GEOLOGY Age, growth	Ordovician, slate & sandstone
TOPOGRAPHY Landscape	Slightly dissected plains
Elevation (range) m	421
Local relief (av.) m	10
Drainage pattern	Dendritic
Drainage density km/km²	3.9
Land form	Rolling Plain
Position on land form	Crest	Long gentle slope	Drainage line
Slope (av.) ,%, slope shape	1-3 ; Convex	3-9 ; Straight	1-3 ; Concave
NATIVE VEGETATION Structure	Woodland	Open forest
Dominant species	E. obliqua, E. radiata	E. viminalis E. obliqua	E. ovata, E. obliqua
SOIL Parent material	In-situ weathered rock	In-situ weathered rock	Alluvium-clay, silt, sand and gravel
Description	Shallow stony red gradational soil	Mottled yellow, red duplex soil	Mottled yellow & red gradational soil
Surface texture	Gravelly loam	Loamy clay	Clay loam
Permeability	High	Moderate-low	Low-moderate
Depth (av.) in	0.6	1	2
LAND USE	Grazing with some forestry and cropping (cereal)
SOIL DETERIORATION Critical land features	Hard setting surfaces, dispersibility	Hard setting surfaces	Moderate dispersibility, poorly drained site, hard setting surfaces
Processes	Overland flow, leaching of salts	Overland flow, leaching of salts	Overland flow, accumulation of salts
Forms	Sheet and rill erosion, compaction	Sheet and rill erosion, gully erosion, compaction	Salting, gully erosion

* Ballan figures

LAND UNIT: Ordovician plain

COMPONENT: 1 – Crests – Shallow stony red gradational soils

MAP SYMBOL: Org 1

CAPABILITY OF THE LAND TO SUPPORT VARIOUS ACTIVITIES			CAPABILITY OF THE LAND TO SUPPORT SUBDIVISION
ACTIVITY	RATING	MAJOR LIMITING FEATURES OF THE LAND	SUBDIVISION TYPE	RATING	MAJOR LIMITING ACTIVITIES
Building houses	8-15% Fair 15+% Poor	Depth to rock of moderate hardness; stoniness.	Urban (sewered)	Poor	Shallow excavations (otherwise-fair: building houses and secondary roads).
Absorption fields	Poor	Stoniness; depth of soil.	Small Farmlets 4 ha	Poor	Small farm dams; absorption fields – effluent (otherwise fair: access tracks; gravel roads; building houses).
Secondary roads	8-12% Fair 12-20% Poor	Depth to rock of moderate hardness; stoniness. Slope-construction.	Large Farmlets 16 ha	Poor	Small farm dams; absorption fields-effluent (otherwise fair: access tracks and building houses).
Gravel roads	8-12% Fair 12-20% Poor	Stoniness. Slope-erosion & damage.	Bush Blocks 4 ha.	Poor	Absorption fields-effluent: clearing for house sites and access tracks.
Access tracks	8-12% Fair 12-20% Poor	Stoniness; erosion of surface. Slope - erosion & damage.
Shallow excavations	Poor	Depth to rock of moderate hardness stoniness.
Small farm dams	Poor	Depth to rook; stoniness; catchment requirements.
Sewerage lagoons	Poor	Depth to rock.
Topsoil - Quality	Poor	Stoniness.
- Removal	Very poor	Thin stony layer.
- Resowing	Very poor	Infertile erodible subsoil; slope - erosion.
Sand - Quality	Very poor	No sand.
- Operation	Fair
Gravel - Quality	Fair	Variable: clay content; stoniness.
- Operation		Erodible soils; slope
Grazing	Fair	Shallow stony soils of low moisture holding capacity and low fertility.
Cultivation	Very poor	Very shallow; stony soils - not cultivated.
Clearing	Poor	Slow revegetation - sheet erosion.

EFFECT OF SUBDIVISION OF THE LAND ON TOWN WATER SUPPLY
URBAN:	Due to the poor soils and dispersible clays, it will be difficult to quickly re-establish vegetation to protect earthworks. There will be a considerable risk of silt lose during development.
FARMLET:	Erosion of gravel roads and tracks will be the main source of turbidity and siltation from farmlet subdivisions. NOTE: this component normally supports low stocking rates. Higher rates or badly managed stock can lead to overgrazing and therefore sheet erosion. Failure of septic absorption fields because of the shallow stony soils will be a major hazard. Percolation rates may be very rapid but the lack of soil depth and high rock fragment content will hinder the treatment of the effluent.
BUSH BLOCK:	As for farmlets, effluent absorption and erosion of roads and tracks will be the main continuing hazards. However, clearing for the construction of roads, tracks and house sites will be a very serious risk during the development stage. Bush block subdivision would require special planning and management to minimise pollution of the water supply.

LAND UNIT: Ordovician plain

COMPONENT: 2 – Long gentle slopes

MAP SYMBOL: Org 2

CAPABILITY OF THE LAND TO SUPPORT VARIOUS ACTIVITIES			CAPABILITY OF THE LAND TO SUPPORT SUBDIVISION
ACTIVITY	RATING	MAJOR LIMITING FEATURES OF THE LAND	SUBDIVISION TYPE	RATING	MAJOR LIMITING ACTIVITIES
Building houses	0-8% Good 8-15% Fair	Erosion during construction; some shrink-swell. Slope - erosion & construction problems.	Urban (sewered)	Fair	Building houses; secondary roads.
Absorption fields	Fair	Variable percolation rates; imperfect drainage; temporary water tables - esp. on cleared land	Small Farmlets 4 ha	Fair	Absorption fields-effluent building houses; gravel roads; access tracks).
Secondary roads	0-8% Good 8-15% Fair	Risk of erosion during construction. Slope - construction and erosion problems.	Large Farmlets 16 ha	Fair	Absorption fields - effluent; building houses; access tracks.
Gravel roads	Fair	Risk of erosion of batters; drains and surface.	Bush Blocks 4 ha.	Fair	Absorption fields - effluent; building houses; gravel roads; access tracks.
Access tracks	Fair	Risk of erosion of surface and drains; soil drainage.
Shallow excavations	Good	Some seasonal drainage problems.
Small farm dams	Good
Sewerage lagoons	Fair	Slope-construction.
Topsoil - Quality	Fair	Too clayey; very hard-setting..
- Removal	Poor	Thin layer
- Resowing	Poor
Sand - Quality	Very poor	No sand.
- Operation
Gravel - Quality	Poor	Gravel deposits are rare or thin layer.
- Operation	Good
Grazing	Good	Soil fertility; impermeable clayey B horizon; hard setting topsoil.
Cultivation	Fair	Impermeable clayey B horizon; hard setting structureless topsoil; erosion.
Clearing	Fair	Soil loss prior to pasture establishment.

EFFECT OF SUBDIVISION OF THE LAND ON TOWN WATER SUPPLY
URBAN:	Although the slopes are gentle, the soil is erodible and impermeable. Bare surfaces shed water readily. The clay, which partially disperses, is easily transported. Unless Land Disturbance guidelines are followed during development, moderate turbidity & silt loads can be expected in the runoff.
FARMLET:	Erosion of batters, drains and surfaces of gravel roads and tracks in subdivisions will be a moderate source of silt and clay. The silt loss can be minimised by correct planning, construction and maintenance. Also, the impermeable clay, commonly causes perched watertables, especially in cleared land. Effluent disposal by soil absorption will cause problems, especially on lower slopes and near drainage lines.
BUSH BLOCK:	As for farmlets. However, clearing for house sites and access will be an additional potential source of silt and clay in the runoff. Soil drainage will generally be somewhat better in uncleared upper and mid slopes.

LAND UNIT: Ordovician plain

COMPONENT: 3 – Drainage line – mottled yellow/red gradational soils

MAP SYMBOL: Org 3

CAPABILITY OF THE LAND TO SUPPORT VARIOUS ACTIVITIES			CAPABILITY OF THE LAND TO SUPPORT SUBDIVISION
ACTIVITY	RATING	MAJOR LIMITING FEATURES OF THE LAND	SUBDIVISION TYPE	RATING	MAJOR LIMITING ACTIVITIES
Building houses	Poor to very poor	Soil drainage surface flows (very poor in flood risk areas).	Urban (sewered)	Poor to very poor	House foundations; secondary roads; shallow excavations.
Absorption fields	Very poor	Soil drainage - seasonal and permanent watertables; percolation rate.	Small Farmlets 4 ha	Very poor	Absorption fields - effluent; access tracks (otherwise poor: building houses and gravel roads).
Secondary roads	Poor	Soil drainage; some flood risk; surface flows; erosion during construction.	Large Farmlets 16 ha	Very poor	Absorption fields - effluent; tracks (other^.wise- poor: building houses).
Gravel roads	Poor	Soil drainage; surface flows; erosion during construction; erosion of drains and surface.	Bush Blocks 4 ha.	Very poor	Absorption fields - effluent; access tracks (otherwise- poor: building houses and gravel roads).
Access tracks	Very poor	Soil drainage; surface flows; erosion of surface and drains.
Shallow excavations	Poor	Soil drainage.
Small farm dams	Fair to good	Variable material for embankment.
Sewerage lagoons	Poor	Flood prone; proximity to watercourse (otherwise: good).
Topsoil - Quality	Good	Thin layer.
- Removal	Fair
- Resowing	Poor	Surface flows; impermeable subsoil; severe erosion risk.
Sand - Quality	Variable	Generally poor quality.
- Operation	Poor	Poor drainage; surface flows; severe erosion risk.
Gravel - Quality	Variable	Generally poor quality.
- Operation	Poor	Poor drainage; surface flows; severe erosion risk.
Grazing	Fair	Soil drainage; pugging of soil; possible gully erosion.
Cultivation	Very poor	Surface flow; fallow wash - rilling; sheet and gully erosion.
Clearing	Poor	Surface flow; topsoil wash prior to pasture establishment.

EFFECT OF SUBDIVISION OF THE LAND ON TOWN WATER SUPPLY
URBAN:	Due to the poor drainage and risk of high velocity floods, such of the land is not capable of supporting urban subdivision without extensive drainage works. However, any development within these drainage lines is likely to contribute significantly to turbidity and silt loads, particularly during construction.
FARMLET:	Although this unit may be included as part of farmlet blocks, it is essential that buildings, access and effluent disposal should be excluded from this unit. Clearing will involve a serious risk of erosion.
BUSH BLOCK:	As with farmlets, this unit may be included as part of bush block, as long as housing access and effluent disposal areas are excluded from this unit.

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