The study focuses on the adjacent Tenthill and Ma Ma catchments which converge onto the heavily cultivated alluvial plain of Lockyer Creek. Groundwater extracted from the alluvial aquifers is the primary source of water for intensive irrigation. Within the study the hydrogeology is investigated, a conceptual groundwater model produced and a numerical groundwater flow model is developed from this. The hydrochemistry and stable isotope character of groundwater are also investigated to determine processes such as recharge and evaporation. Examination of bore logs confirms the Quaternary alluvium comprises a laterally continuous gravel aquifer with an average thickness of 4.5 m, overlain by mixed sands and clays which form a semi-confining layer with an average thickness of 22 m. Variations in long term groundwater hydrographs indicate the aquifer changes from confined to unconfined in some locations as water levels drop, while bores adjacent to creek banks display a rapid response to a flood event. Pump testing of bores screened in the gravel produces estimates of hydraulic conductivity ranging from 50-80 m/day and storativity of 0.00166 which are both within realistic bounds for this aquifer material. Major ion chemistry of surface water collected during a flood is Mgdominated, similar to alluvial groundwater in the Tenthill catchment and the Lockyer plain, suggesting a strong connection between surface and groundwater in these locations. Alluvial groundwater salinity in Tenthill catchment is typically less than 3500 ìS/cm but may approach 6000ìS/cm on the Lockyer plain. By contrast Ma Ma catchment alluvial groundwater is Na-dominated with conductivity up to 12000 ìS/cm and more associated with groundwater from the underlying sandstone bedrock. Stable isotope analyses of alluvial groundwater from throughout both catchments and the Lockyer plain are compared with basalt and sandstone groundwater. A range of processes have been identified including recharge to alluvium from basalt groundwater and evaporated surface water; and alluvial-bedrock groundwater mixing at some locations. Integration of the components of the study enabled the production of a conceptual hydrogeological model of the Lockyer alluvial plain, proposing two hydrostratigraphic units; the gravel aquifer and the overlying mixed sand and clay which acts as a semi confining unit. Hydrochemical and stable isotopic evidence suggests seepage from creek channels as the dominant recharge process. A single layer groundwater flow model using MODFLOW was developed, based on groundwater extraction data, to represent flow in the gravel aquifer. The model was calibrated to transient conditions with groundwater fluctuations, incorporating both drought and flood conditions. A sensitivity analysis for each of the aquifer properties demonstrates the model is insensitive to variations within realistic bounds for the gravel aquifer material, however, the model is highly sensitive to changes in the chosen boundary conditions. Predictive simulations with several annual extraction scenarios ranging from 1.75 to 0.5 ML/ha indicate the resulting minimum saturated aquifer thickness ranges from 0.03 to 1.4 m.

This study was conducted in two shires of Laidley and Gatton in the Lockyer Valley in 1986. The research method used was a self-administered mail questionnaire sent to four hundred primary producers. The response rate received was 49.5 percent which is quite reasonable for a random sample of a non-specific interest group. The study area was divided into six zones based on the 198 respondents’ assessment of the enterprise from which they derived major income. The main approach of this project was a situational analysis o the Lockyer Valley. Central to this research was identification of the pressure and extent of problems relating to several aspects of land use, notably soil erosion, weed infestation; availability and quality of water and more general community-based problems. The characteristics of farm households, the role of family members in decision-making and tasks related to farm as well as home, were also included in this study. The Lockyer Valley is a major production area of vegetables as well as a mixed farming area. Natural pasture, which was extensively found in Zone 6, was largely used for cattle grazing. Generally, rural women were better educated than their husbands, and the ratio of educational level of husband and wife was higher than previous research findings. A large number of producers and their wives have taken off-farm work, and women tended to spend more time in off-farm employment. Only 6.1 percent of producers’ children had completed tertiary education and the majority of all sons were working on the farm. Partnership was found to be the major type of property ownership and inter-generational transfer of the property was the future plan. The producers who were from a non-farm upbringing and who had already taken up off-farm work intended to leave their properties at some time in the future. With the running of the farm business , 35 percent of rural women worked full-time in partnership with their husbands, and 42 percent worked part-time. However, 23 percent of rural women were homemakers and were not involved in running the farm business. The association between decision-making of husband and wife and situational factors such as ownership, involvement in farm tasks, record-keeping, education, on-farm upbringing and age were analysed. Joint involvement of wives in decision-making was to be related to ownership, farm tasks and record-keeping. However, husbands were more likely to take a major role in decision-making if they were more educated and had an on-farm upbringing. Age was found to be a factor affecting joint decision-making, although this result conflicted with findings of earlier research. The opinions of the farm community in identifying the problems of the specific small area in the Lockyer Valley were revealed. Lantana was the most severe weed problem in the whole catchment. The catchment area also had problems with wattle. The recommended control method of lantana was replacement by improved pasture, but it was adopted by few primary producers. Soil erosion in the form of gullies, bank erosion, sheet erosion, salinity and flooding were some of the problems perceived by the local community. Regular ‘slash and burn’ was practised by most of the producers. This is one of the causes of land degradation. Bore, creek and river, and dam were the main water sources for farm supply and irrigation. Only 60 percent of bored had adequate water supply and good water quality. Farm dam and creek/river sources were less reliable due to the inadequate availability of water. Consequently, operators at about half the cropped farms had to stop growing some vegetables which were previously commercially successful. Within the context of farm family needs, emphasis was placed on conservation of water, because of the erosion and water problems. The community’s opinion on community development activities emphasised the involvement of farm families. Finally, suggestions for the extension program which should be emphasised on rural development by means of community participation were included. The bases for further studies was also provided in this report.

This study was conducted in two shires of Laidley and Gatton in the Lockyer Valley in 1986. The research method used was a self-administered mail questionnaire sent to four hundred primary producers. The response rate received was 49.5 percent which is quite reasonable for a random sample of a non-specific interest group. The study area was divided into six zones based on the 198 respondents’ assessment of the enterprise from which they derived major income. The main approach of this project was a situational analysis o the Lockyer Valley. Central to this research was identification of the pressure and extent of problems relating to several aspects of land use, notably soil erosion, weed infestation; availability and quality of water and more general community-based problems. The characteristics of farm households, the role of family members in decision-making and tasks related to farm as well as home, were also included in this study. The Lockyer Valley is a major production area of vegetables as well as a mixed farming area. Natural pasture, which was extensively found in Zone 6, was largely used for cattle grazing. Generally, rural women were better educated than their husbands, and the ratio of educational level of husband and wife was higher than previous research findings. A large number of producers and their wives have taken off-farm work, and women tended to spend more time in off-farm employment. Only 6.1 percent of producers’ children had completed tertiary education and the majority of all sons were working on the farm. Partnership was found to be the major type of property ownership and inter-generational transfer of the property was the future plan. The producers who were from a non-farm upbringing and who had already taken up off-farm work intended to leave their properties at some time in the future. With the running of the farm business , 35 percent of rural women worked full-time in partnership with their husbands, and 42 percent worked part-time. However, 23 percent of rural women were homemakers and were not involved in running the farm business. The association between decision-making of husband and wife and situational factors such as ownership, involvement in farm tasks, record-keeping, education, on-farm upbringing and age were analysed. Joint involvement of wives in decision-making was to be related to ownership, farm tasks and record-keeping. However, husbands were more likely to take a major role in decision-making if they were more educated and had an on-farm upbringing. Age was found to be a factor affecting joint decision-making, although this result conflicted with findings of earlier research. The opinions of the farm community in identifying the problems of the specific small area in the Lockyer Valley were revealed. Lantana was the most severe weed problem in the whole catchment. The catchment area also had problems with wattle. The recommended control method of lantana was replacement by improved pasture, but it was adopted by few primary producers. Soil erosion in the form of gullies, bank erosion, sheet erosion, salinity and flooding were some of the problems perceived by the local community. Regular ‘slash and burn’ was practised by most of the producers. This is one of the causes of land degradation. Bore, creek and river, and dam were the main water sources for farm supply and irrigation. Only 60 percent of bored had adequate water supply and good water quality. Farm dam and creek/river sources were less reliable due to the inadequate availability of water. Consequently, operators at about half the cropped farms had to stop growing some vegetables which were previously commercially successful. Within the context of farm family needs, emphasis was placed on conservation of water, because of the erosion and water problems. The community’s opinion on community development activities emphasised the involvement of farm families. Finally, suggestions for the extension program which should be emphasised on rural development by means of community participation were included. The bases for further studies was also provided in this report.