Region: Portland

Legal Number: LEGL/93-23

Plantation: Mocamboro

Approximate Plantation Size: 500ha

93-23a Jan 01: Pine clearance on mild slopes. Herbicide use in this water catchment is a major concern as drawdown into groundwater could tarnish domestic water supply. Water yield is also very likely to be decreased by pine plantations.

Conservation Priority: High

The Nationally Threatened Temperate Grassland & Grassy Eucalypt Woodland Ecological Community may occur in this plantation or in close proximity.

Plantation located on Victorian Volcanic Plain Bioregion.

More Information:

Plantation within S.E.A.S Sapfor (Auspine) area of supply.
Plantation within AKD Softwoods area of supply.

Plantation maps of region here

Aerial View of MocamboroPlantations looking north-east. Photo dates from approximately 2005.

Declared Water Catchment: Almost entire Plantation located in Merino Proclaimed Water Catchment. Proclaimed 18/12/85.

Map showing extent of Hancock plantations within Merino Water Catchment boundaries.

This plantation was very likely to be aerially sprayed with 2,4,5-T between 1968 and 1977. The Dioxin TCDD may still exist in soil in this plantation. For more historical data on 2,4,5-T click here. For more information concerning the continuing health crisis concerning 2,4,5-T please forward to here.

Herbicides Used by Hancock in Pine Plantations South Western Victoria

Label Rate max as kg/ha
Used to control
Woody Weeds
Highly Toxic/Potential Ground water Contaminant
air or ground
Herbaceous and woody weeds, noxious weeds
Woody Weeds
Ground Water Contaminant
Aerial, ground, spot
Woody Weeds, Noxious Weeds
Potential Ground Water Contaminant
Aerial, ground or spot
Woody and Noxious Weeds
Ground, spot, basal bark


July 2003: Widespread clearfelling has recently occurred in this very important south west Victorian water supply catchment. Regrowing pine trees are bound to have a serious impact on groundwater yield in Merino's water supply catchment. Note retained indigenous vegetation in right hand side of photo.

Responsible Authority: Glenelg Shire Council

THREATENED FISH NOTES - GLENELG RIVER: Yarra Pygmy Perch and Ewens Pygmy Perch found in the Glenelg system. Both species listed under the Flora and Fauna Guarantee Act in Victoria and threatened.

THREATENED FISH NOTES - WANNON RIVER: Yarra Pygmy Perch found in the Wannon system.

Feb 04: Chronic radita pine weed infestation of Mocamboro native forest.

Plantation Catchment: Eastern edge of Mocambora State Forest - seperates west from east. South of coupe lies on/next to Dwyer Creek-flows north into Wannon River/meets Glenelg south of Casterton. Northern side lies in headwaters of Bowtell Creek which runs north into Glenelg River.

Catchment Managment Authority: Glenelg-Hopkins Catchment Management Authority.

Hancock Watch Site visit Jan 01: This area appear to be pine on mild slopes. Logging activity taking place when visited making analysis difficult. The plantation is of high conservation importance due to its location in the Merino Proclaimed Water Supply Catchment. Groundwater occurs in the fine grained, poorly cemented polyzoal limestones of Tertiary age. The recommended protection zone No 2 of groundwater sources could not be created in the 1980's because of new pine plantations.

July 2003: View looking south taken from Kilmoc Road. Widespread logging is taking place in this catchment, with clearfells extending over several kilometres in the north eastern aspect of the Merino Water Supply catchment. How much herbicide will be used in this plantation to kill competing native vegetation over the next couple of years?


Department Conservation, Forests and Land, April 1985.

“p1 The Western Victorian township of Merino (population 300) and approximately 20 outlying rural properties obtain domestic water supply from two groundwater bores. The intake area (“catchment”) of 5,100 ha has been delineated by the Department of Minerals and Energy using geohydrological criteria . . .


Catchment area: 5,100 hectares.

Rainfall: 700 mm per annum.

Evaporation: 600mm per annum (net).

Geology: Quaternary sands, Tertiary sandstones, marls and limestones.

Soils: Coarse loamy sands.

Vegetation: Unimproved pasture (760 ha), Dry sclerophyll forest (3843 ha), Softwood plantation (477 ha).

Elevation: 100 - 185 metres.

Topography: Flat to undulating.

Relief: 10 - 20 metres.

p2 The Supply System: The two production bores about 2.2km apart, tap a multiple aquifer system at depths between 1 & 85 mm. Their cones of influence are some 400m in radius. The aquifers rely on vertical infiltration of rainwater for recharge with responses to rainfall occurring within a few days. Water is aerated in the bore, pumped to the surface and piped to a retention basin (20 ML) capacity near Merino township. At present the system supplies 50 ML annually. . .

Hazards to the Water Supply

The major issues confronting management for water supply purposes include small lot subdivision, development of softwood plantations, herbicide and fertilizer use. The Department of Minerals and Energy has expressed concern that the development of softwood plantations on private land, may affect interception and evapotranspiration rates leading to a diminution of the amount of water available to recharge the shallow aquifer. Long term protection of supply is sought, to ensure an adequate quantity of water will be available for future developments. Annual recharge amounts to 120 ML with a projected withdrawal of 100 ML per annum.

A further concern is that herbicides, fertilizers, septic effluent or waste from intensive animal industries may pose a threat to the quality of the supply. Rapid hydraulic conductivity throughout the soil profile may not allow sufficient detention time to allow degradation of pollutants or herbicides such as ‘Roundup’, ‘Velpar’ or ‘Lontrel’. In times of rapid drawdown such compounds might readily access the water supply . . .”

Wannon River below Wannon Falls: Some brown trout to 1.3kg, golden perch to 1.4kg, redfin to 1kg, eels and tupong in the lower reaches.

Source: A Guide to the Inland Angling Waters of Victoria by BR Tunbridge, PL Rogan, CA Barnham. Department Conservation and Environment. Arthur Rylah Institute for Environmental Research, 123 Brown St, Heidelberg, 3084. (4th ed - 1991)


"Groundwater: "In south-western Victoria the Otway Basin stretches from the South Australian border almost to the west of Geelong. It contains older sediments of Upper Cretaceous and Lower Tertiary age, up to 2000 m in thickness. These include four sand aquifers and two limestone aquifers. The sand aquifers of the Wangerrip Group are confined over most of the Basin and their recharge zones are located on the margins of the Otway Range in the east and the Merino Tablelands in the West. The groundwater moves towards the coast, increasing in salinity along its floorpath . . ." p268 State of the Environment Report 1988 Victoria's Inland Waters. Office of the Commissioner for the Environment.

"Shallow aquifers in the Glenelg River Basin occur in four main geologic units. Extending from the north-east of the Basin is a fractured rock basement aquifer composed of folded sediment, metamorphics and granite. In the north-east and also in the vicinity of the confluence of the Glenelg and Wannon Rivers, the basement aquifer is overlain by alluvial aquifers from the Quaternary period. The third unit is a Newer Volcanic aquifer which lies along much of the Basin's southern boundary, particularly in the east. This fractured rock aquifer is composed of basalt, scoria and tuff. The fourth unit is composed of dune sand and beach deposits extending from the south-west corner of the Basin up to the western boundary and along the northern boundary. It is known as the Bridgewater formation.

A deep aquifer system exists in the south-west of the Basin and extends to the top of the western boundary and half-way across the southern boundary. This sand aquifer, which is significant as a water source, occurs within the Wangerrip Group.

Generally, groundwater quality in the Basin decreases towards the north where it is saline. A large reserve of fresh water is held in the north-east corner of the catchment and in the south-west the water is of marginal quality . . ." p295 Water Victoria A Resource Handbook - Department of Water Resources Victoria 1989.


Victree S.E.A.S Sapfor Yarra Pygmy Perch Auspine Golden Perch Ewens Pygmy Perch Redfin Trout Tupong Eels Wannon River Glenelg River Low Portland