Evaporation from the soil is an important part of the water balance of a crop, when considering water use efficiency. In this paper, a non-intensive method is tested to estimate relative soil evaporation, which is based upon a linear function of soil surface temperature change between a saturated and drying soil. The relative evaporation (RE) method of Ben-Asher et al. (1983) was calibrated using microlysimeters and thermal imaging. Soil surface temperature in a drip irrigated vineyard was then collected using infrared temperature sensors mounted on a quad bike, on several days of the 2009-2010 season. Soil surface temperature in the vineyard ranged from 4.6 °C to 65.5 °C undervine and 6.8 °C to 75.6 °C in the middle of the row. The difference between daily minima and maxima of soil surface temperature ranged from 20.2 °C to 59.7 °C in the inter-row and 13.6 °C to 36.4 °C undervine. Relative evaporation averaged 54% of evaporation from a saturated soil in the inter-row and 97% undervine. Based upon the calculation of RE, the average daily amount of soil evaporation undervine was between 0.64 mm and 1.83 mm, and between 0.69 mm and 2.52 mm inter-row. The soil evaporation undervine and inter-row both exhibited spatial variability across the vineyard, however the undervine area had less spatial variability compared to the inter-row area.

Waterlogging and soil salinisation is widespread in the semiarid, irrigated areas of the world. Subsurface drainage is a useful tool in reducing these effects on crops; however, there has been negative downstream effects of drainage in the salt loads discharged to rivers, lakes, and wetlands. Thus, subsurface drainage in semiarid, irrigated areas needs to balance the demands of providing adequate waterlogging and salinity control while minimizing salt loads. Bilevel drainage, in which shallow drains are placed between deeper drains, is a potential method to meet this required balance. This paper describes the development of an analytical solution to this design approach. A previous potential theory was extended to incorporate multiple series of shallow drains placed between two deep drains. The analytical solution was then applied using the Mathematica software to provide useful information on flow rates and flow lines with varying configurations of deep and shallow drains. The theory was then used to compare spacing and drain flow characteristics between a drainage system with only deep drains and multilevel systems that combine shallow drains with deep drains. A large number of possible configurations of shallow drains between deeper drains exist. For ease of comparison, the concept of "drainage equivalence" was developed, representing the drainage discharge per unit spacing between drains. The analytical solution for bilevel drainage situations with single and multiple shallow drains between deeper drains showed that for equivalent rates of total drainage, spacing between deep drains could be increased significantly by the use of shallow drains. It also demonstrated that flow paths and drainage rates from shallow and deep drains and the total system drainage could be altered significantly by altering the number of shallow drains. This information should be useful when considering various drainage configurations to meet the dual objectives of root zone salinity control and minimization of drainage salt loads.

Soil evaporation is a significant unproductive loss of water that needs to be and can be managed in irrigated systems. A method is used to estimate soil evaporation based upon soil surface temperature change between a saturated and drying soil. The relative evaporation (RE) method of Ben-Asher et al. (1983) was deployed. Soil surface temperature in a drip irrigated vineyard was collected using infra-red temperature sensors. Average daily soil evaporation under-vine was between 0.6mm and 1.8mm and between 0.7mm and 2.5mm for the inter-row. Evaporation from the soil is an important part of the water balance of a crop (Burt et al. 2005). Previous estimates vary widely, from 30-65% of evapotranspiration (Kerridge et al 2008a). The Ben-Asher et al. (1983) method allows potential soil evaporation to be estimated from the daily latent fluxes of a saturated, steady-state dry and a drying soil. By calculating a relative evaporation (RE) factor and multiplying it by an estimate of potential evaporation, determined for example by the FAO-56 procedure (Allen et al., 1998), an estimate of soil evaporation may be made. The main benefit of this method is that it allows rapid and simultaneous estimates of evaporative flux to be measured at numerous sites under study. This can then be linked with methods for spatial estimation of plant water use and stress (Hornbuckle et al., 2008b).

Tropical cyclone induced flooding has had limited research despite the regularity of occurrence, extensive damage, and fatalities associated with these events. In Australian coastal waters, cyclogenesis frequently occurs close to the coast, with little lead time for specific warnings announcement. The identification of predictors for tropical cyclone induced flood events would be of benefit to emergency services. The aims of this research are to address this gap by analysing the relationship between tropical cyclones and flood generation. Tropical cyclones are complex multifaceted systems. Therefore, this research was completed in three phases: 1. analysis of hydrology and climatic data to distinguish flood origin and importance of tropical cyclone flood generation at a catchment level; 2. identification of the differentiating attributes of tropical cyclones; and, 3. prioritisation of tropical cyclone attributes as predictors of flood severity, magnitude and extent.

Flooding and the influence of cyclogenesis on the Barron River, located in the Wet Tropics, Far North Queensland, Australia, was investigated. This catchment experiences, on average, 1.4 tropical cyclones within a 400 kilometre radius per season. Between 1915 and 2014, 50 percent of all annual peak discharges greater than a two year average recurrence interval were associated with a tropical cyclone. This percentage of occurrence increased to greater than 80 percent in all sections of the catchment, for floods with an average recurrence interval of greater than 20 years.

Nine tropical cyclone attributes were distinguished through examination of the historical record and dissection of radar images of East Coast, Australia, landfalling tropical cyclones. The identified tropical cyclone attributes (landfall location or proximity to the coast; direction of movement; category; duration within the catchment; size; rainfall volume; rainfall distribution; rainband asymmetry; and rainband rotation at landfall) were evaluated to determine their potential as tropical cyclone induced flood indicators. A MIKE 21 hydrodynamic model (DHI, 2011) was constructed for the catchment. Manipulation of the tropical cyclone inputs enabled the isolation of the variables. Statistical analysis prioritised the importance of the attributes as predictors of flood severity, magnitude and extent. Of the four predictors recognised, two primary attributes were identified to be of high importance to flood prediction (rainband asymmetry; and location of landfall or proximity to the coast). Secondary attributes were tropical cyclone category and size. The inclusion of the rainband asymmetry within tropical cyclone warnings or models represents a potential tool for flood prediction and management strategies.