Ravensthorpe area catchment appraisal 2006

The Ravensthorpe area covers 861, 000 hectares. Ninety percent of the study area covered in this report falls within the Ravensthorpe Shire, Western Australia. This document aims to give the reader a starting point from which to further assess larger scale areas of the catchment for the purpose of planning to reverse and improve land degradation and sustainable farming in Western Australia

Controlling evaporation loss from water storages

[Executive Summary]: Evaporation losses from on-farm storage can potentially be large, particularly in irrigation areas in northern New South Wales and Queensland where up to 40% of storage volume can be lost each year to evaporation. Reducing evaporation from a water storage would allow additional crop production, water trading or water for the environment. While theoretical research into evaporation from storages has previously been undertaken there has been little evaluation of current evaporation mitigation technologies (EMTs) on commercial sized water storages. This project was initiated by the Queensland Government Department of Natural Resources and Mines (NRM) with the express aim of addressing this gap in our knowledge. The report addressed i) assessment of the effectiveness of different EMT’s in reducing evaporation from commercial storages across a range of climate regions, ii) assessment of the practical and technical limitations of different evaporation control products, and iii) comparison of the economics of different EMT’s on water storages used for irrigation

Shay Gap soil survey: investigating the suitability of soils and landforms for irrigated agriculture in the western West Canning Basin

This report describes the soil and land resources of the Shay Gap study area (SA), which is south of Wallal Downs Station, in unallocated Crown land in the Shire of East Pilbara. It assesses the study area’s capability for three types of irrigated agriculture and examines land resources to ensure any future irrigation developments are sustainable and do not degrade the environment. The Shay Gap SA lies within the West Canning Basin, an area of about 3500 square kilometres at the western margin of the onshore Canning Basin. The West Canning Basin has a substantial groundwater resource that provides fresh and fit-for-purpose water for a variety of uses. Land use is intensifying nearby, via irrigation of soils and landforms similar to the Shay Gap SA. Small- to medium-scale horticulture enterprises have been developed over the past 30 years in the La Grange area. The soils of surrounding areas that are currently used for irrigation are deep red sands and red sandy earths. They are well drained to rapidly drained and have no perched watertable, potentially enabling year-round production. Analyses from established horticultural properties indicate soils do not show any chemical or major physical limitations that would prevent their use for irrigated agriculture, provided that production systems maintain a balanced water and nutrient regime for optimal crop growth. The main degradation hazard limiting the agricultural capability of soil and landscapes in the Shay Gap SA is erosion by wind and water. Other hazards — subsoil acidification and compaction — will require ongoing monitoring and management intervention. The ionic constituents of irrigation water will require monitoring and may influence management practices because of the low pH and phosphorus buffering capacity of the soil. This land assessment identified 1430 hectares (ha) of land with fair capability for irrigated agriculture of high productive capacity, and another 11 000ha with fair capability for irrigated agriculture of moderate productive capacity, should sufficient water reserves be identified

An investigation into the use of the freshwater crayfish marron (cherax tenuimanus) as a flagship for the restoration of the Blackwood River

The Marron (Cherax tenuimanus) is arguably the most easily identified and ecologically important aquatic animal species in south-western Australian rivers. In fact it is quintessientially south-western Australian, endemic to the south-west corner of the continent and supporting a recreational fishery and commercial aquaculture industry within the state. Marron have keystone qualities as hosts of various epiphytic flora and fauna, and are central to the food web within south-west rivers. Their sensitivity to depleted oxygen conditions have also made them a potential indicator for water quality degradation. The study investigated these qualities in reference to the marron\u27s potential as a flagship species for the restoration of the Blackwood River. Marron could, as flagships, provide direction and understanding for an already community driven catchment group, and provide a focal point for research, landcare, and foreshore restoration along the Blackwood River. According to a list of criterion for flagship species selection the study reviewed the literature on the scientific knowledge and ecological, cultural and economic value of marron within the south-west. The marron \u27s ability to recover from threatening processes within the Blackwood River was investigated, based on an earlier study in 1973. Seven pools within the Middle Catchment (the study area) were sampled for marron using a competitive density of drop nets within each pool, followed by the mapping of cross-sectional dissolved oxygen profiles. The upper limit of marron distribution was confirmed to be approximately 100km below the original upper limit maintained until the late 1950\u27s. Depleting oxygen concentration associated with persistent stratification and organically enriched sediments and high water temperatures were identified to have the potential to lock marron out of pools, at certain times of the day during the summer months. These threatening conditions could be ameliorated with daily or seasonal holomixis and the flushing effect of winter rain, thus enabling marron recovery. A face to face questionnaire sampling the Middle Blackwood Catchment community was used to test the marron\u27s ability, to evoke public sympathy and pride, and assess marron popularity and appeal. Marron fulfilled all criteria tested, with significant variation in opinion and attitudes identified between shires, gender of respondent, river use and those involved in the recreation of marron fishing. The study found marron to be an appropriate flagship species for restoration of the Blackwood River. It represents an appealing icon for tangible community understanding of the restoration process, and a biological indicator for monitoring change as restoration becomes effective, providing direction for restoration action, milestones for the community, and an endpoint for the restoration programme