Physical Sciences and Mathematics Commons^™

Degradation Of Remnant Vegetation, Richard George, Don Mcfarlane, Russell Speed

Journal of the Department of Agriculture, Western Australia, Series 4

Remnant vegetation, wetlands and riverine systems on both private and public land throughout south-western Australia are being rapidly degraded by dryland salinity, inundation, silting, nutrient enrichment and weed invasion. Richard George, Don McFarlane and Russel Speed outline some of the reasons why this is happening and provide some case studies that highlight actions to protect these remnants.

Increasing Groundwater Salinity In The Northern Wheatbelt, R J. Mcgowan

Journal of the Department of Agriculture, Western Australia, Series 4

Every farmer in western Australia's northern wheatbelt will know of a groundwater supply, be it bore, well or soak. that has become increasingly saline. The groundwater may have become more saline over a period of 15 years or more, or have been noticed only recently. Inevitably, the bore will lie within an area cleared for agriculture. This increase in groundwater salinity may be associated with soil salinisation. Although researchers have some understanding of the processes causing salinisation of groundwater in the wheatbelt and the extent of the problem, little is known about the rates of salinisation and groundwater rise. A …

Northern Wheatbelt Water Supply Study, I A F Laing, R. M. Pridham

Journal of the Department of Agriculture, Western Australia, Series 4

Department of Agriculture surveys have shown that many farms in Western australia's northern wheatbelt have inadequate water supplies. More than 80 per cent of all farms in that area depend soley on groundwater for watering livestock, a much higher percentage than for most other farming areas. Because groundwater salinities have increased in recent years, concern is held for the long-term future of this recource.

In contrast to more southern agricultural areas, farm dams in the northern wheatbelt are relatively uncommon. Only 30 per cent of the existing dams in the northern wheatbelt constitute effective water supplies. More than half of …

Underground Water Supplies In The Wheatbelt, T T. Bestow

Journal of the Department of Agriculture, Western Australia, Series 4

Underground water originates from rainfall. The size of the underground recource in any region is broadly related to the amount of rainfall. However, rainfall intensity and seasonal distribution are just as importent as the quality. A relatively small annual fall which consists of a series of heasvy showers or storms close together, may be a more effective source of recharge to underground water than a larger fall that is more evenly distributed over a longer period.

A large annual rainfall, however, is no guarantee that underground water supplies will be readily available. This is because soils and the underlying rocks …

Groundwater In The Wheatbelt, E P. O'Driscoll

Journal of the Department of Agriculture, Western Australia, Series 4

In general six factors affect the occurence of groundwater; rainfall, topography, rock type, rock structurs, vegetation, and local evaporation.

Variation in even one of these can affect the potential yield of a bore or well, the groundwater salinity, and even whether any groundwater occurs at all.

Irrigating With Underground Water, T C. Calder

Journal of the Department of Agriculture, Western Australia, Series 4

MANY farmers in South-West areas are looking to irrigation to increase and diversify farm production, particularly on the sandy coastal plain where irrigation in summer is essential for vegetable, fruit and fodder production.

The Relationship Of Flooding And Saline Water Tables, Stanley Thomas Smith

Journal of the Department of Agriculture, Western Australia, Series 4

IN Western Australia there are several ways in which salt manifests itself but the most serious and extensive of these is in the valley systems where shallow saline water tables occur.

This type of salt problem is called "valley waterlogging" and occurs in most of the flat valleys throughout the wheatbelt of W.A.

The Quality Of Groundwaters In The Central Wheatbelt Of W.A, Eric Bettenay, F. J. Hingston

Journal of the Department of Agriculture, Western Australia, Series 4

IN south-western Australia permanent rivers are virtually absent and the larger drainage systems such as the Swan-Avon, Murray and Blackwood, which have their headwaters in inland low rainfall areas, are generally saline.