Water balance and the water-table in deep sandy soils of the upper south-east, South Australia

1960 ◽  
Vol 11 (6) ◽  
pp. 970 ◽  
Author(s):  
JW Holmes
Keyword(s):  
Soil Water ◽  
Water Table ◽  
South Australia ◽  
Soil Water Storage ◽  
Annual Rainfall ◽  
Wetting Front ◽  
Wet Season ◽  
The Mean ◽  
Upper South ◽  
Static Level

A water-table occurs at an average depth of 11.3 m below the surface in deep sand country of the upper south-east of South Australia (County Cardwell). By observing the depth to which water penetrated into the soil profile during the wet season, and the static level of the water in bore-holes, it was proved that the watertable was not replenished by local rainfall. In three years of records, the wetting front penetrated 6.0, 2.1, and 3.6 m on the average, and the soil water thus stored was all used by the prevailing vegetation, either natural mallee heath or lucerne. The performance of the vegetation growing on the deep sand in ability to resist drought was characterized quantitatively by the supply rate of soil moisture as a function of the soil water storage. It was estimated that the yearly potential evaporation for 1957 was 113 cm. The mean annual rainfall is about 50 cm. The ground-water comes, it is suggested, from intake areas about 40 km east of the area under study, where surface floodwaters accumulate in wet seasons. The quantity of water flowing through the aquifer at present is calculated to be about 37 m3/(metre width of strip)/year.

scholarly journals Soil water storage and groundwater behaviour in a catenary sequence beneath forest in central Amazonia: I. Comparisons between plateau, slope and valley floor

1997 ◽  
Vol 1 (2) ◽  
pp. 265-277 ◽  
Author(s):  
M. G. Hodnett ◽  
I. Vendrame ◽  
A. De O. Marques Filho ◽  
M. D. Oyama ◽  
J. Tomasella
Keyword(s):  
Soil Water ◽  
Water Table ◽  
Water Storage ◽  
Dry Season ◽  
Valley Floor ◽  
Soil Water Storage ◽  
High Porosity ◽  
Wet Season ◽  
Deep Drainage ◽  
Shallow Water Table

Abstract. Soil water storage was monitored in three landscape elements in the forest (plateau, slope and valley floor) over a 3 year period to identify differences in sub-surface hydrological response. Under the plateau and slope, the changes of storage were very similar and there was no indication of surface runoff on the slope. The mean maximum seasonal storage change was 156 mm in the 2 m profile but it was clear that, in the dry season, the forest was able to take up water from below 3.6 m. Soil water availability was low. Soil water storage changes in the valley were dominated by the behaviour of a shallow water table which, in normal years, varied between 0.1 m below the surface at the end of the wet season and 0.8 m at the end of the dry season. Soil water storage changes were small because root uptake was largely replenished by groundwater flow towards the stream. The groundwater behaviour is controlled mainly by the deep drainage from beneath the plateau and slope areas. The groundwater gradient beneath the slope indicated that recharge beneath the plateau and slope commences only after the soil water deficits from the previous dry season have been replenished. Following a wet season with little recharge, the water table fell, ceasing to influence the valley soil water storage, and the stream dried up. The plateau and slope, a zone of very high porosity between 0.4 and 1.1 m, underlain by a less conductive layer, is a probable route for interflow during, and for a few hours after, heavy and prolonged rainfall.

scholarly journals Soil water storage and groundwater behaviour in a catenary sequence beneath forest in central Amazonia. II. Floodplain water table behaviour and implications for streamflow generation

1997 ◽  
Vol 1 (2) ◽  
pp. 279-290 ◽  
Author(s):  
M. G. Hodnett ◽  
I. Vendrame ◽  
A. De O. Marques Filho ◽  
M. D. Oyama ◽  
J. Tomasella
Keyword(s):  
Soil Water ◽  
Water Table ◽  
Dry Season ◽  
Water Levels ◽  
Soil Water Storage ◽  
Published Data ◽  
Wet Season ◽  
Deep Drainage ◽  
Forested Catchments ◽  
Streamflow Generation

Abstract. Valley floor groundwater level data collected during the ABRACOS project (Gash et al. 1996), and published streamflow data from small forested catchments in geomorphologically similar areas nearby have been analysed to improve the understanding of the processes of streamflow generation. Early in the wet season, the floodplain water table is typically at 0.8 m depth, or less, and receives only local, vertical recharge. Large storms may create a groundwater ridge beneath the floodplain, temporarily creating a gradient in the direction of the hilislope. Later in the wet season, floodplain water levels are controlled primarily by the discharge of groundwater which maintains the dry season streamflow. The groundwater is recharged by deep drainage from beneath the plateau and slope areas once the dry season soil water deficit has been overcome. In the late wet season, the water level is almost at the floodplain surface and may create seeps on the lower slopes in very wet years. For the period 1966-1989, the recharge was estimated to range from 290 mm to 1601 mm with a mean of 1087 mm. Published data show that baseflow is 91% of annual runoff. Stormflow is generated on the floodplain, and water table recessions after rainfall events show that the runoff response depends on the depth to the water table. These results are from areas with deeply weathered and permeable soils; in areas of Amazonia with shallower soils, the predominant flow generation processes will differ (Elsenbeer and Lack, 1996).

Water balance changes in a crop sequence with lucerne

2001 ◽  
Vol 52 (2) ◽  
pp. 247 ◽  
Author(s):  
F. X. Dunin ◽  
C. J. Smith ◽  
S. J. Zegelin ◽  
R. Leuning
Keyword(s):  
Soil Water ◽  
Water Uptake ◽  
Soil Depth ◽  
Water Storage ◽  
Growing Season ◽  
Soil Water Storage ◽  
Annual Rainfall ◽  
Root Extension ◽  
Annual Crops ◽  
Lower Productivity

In a detailed study of soil water storage and transport in a sequence of 1 year wheat and 4 years of lucerne, we evaluated drainage under the crop and lucerne as well as additional soil water uptake achieved by the subsequent lucerne phase. The study was performed at Wagga Wagga on a gradational clay soil between 1993 and 1998, during which there was both drought and high amounts of drainage (>10% of annual rainfall) from the rotation. Lucerne removed an additional 125 mm from soil water storage compared with wheat (root-zone of ~1 m), leading to an estimated reduction in drainage to 30–50% of that of rotations comprising solely annual crops and/or pasture. This additional soil water uptake by lucerne was achieved through apparent root extension of 2–2.5 m beyond that of annual crops. It was effective in generating a sink for soil water retention that was about double that of annual crops in this soil. Successful establishment of lucerne at 30 plants/m2 in the first growing season of the pasture phase was a requirement for this root extension. Seasonal water use by lucerne tended to be similar to that of crops in the growing season between May and September, because plant water uptake was confined to the top 1 m of soil. Uptake of water from the subsoil was intermittent over a 2-year period following its successful winter establishment. In each of 2 annual periods, uptake below 1 m soil depth began late in the growing season and terminated in the following autumn. Above-ground dry matter production of lucerne was lower than that by crops grown in the region despite an off-season growth component that was absent under fallow conditions following cropping. This apparent lower productivity of lucerne could be traced in part to greater allocation of assimilate to roots and also to late peak growth rates at high temperatures, which incurred a penalty in terms of lower transpiration efficiency. The shortfall in herbage production by lucerne was offset with the provision of timely, high quality fodder during summer and autumn. Lucerne conferred indirect benefits through nitrogen supply and weed control. Benefits and penalties to the agronomy and hydrology of phase farming systems with lucerne are discussed.

The effect of fallowing on the yield of wheat. I. The effect on soil water storage and nitrate supply

1978 ◽  
Vol 29 (4) ◽  
pp. 653 ◽  
Author(s):  
RJ French
Keyword(s):  
Water Storage ◽  
South Australia ◽  
Summer Rainfall ◽  
Soil Water Storage ◽  
Wheat Crop ◽  
Two Factors ◽  
Soil Preparation ◽  
Additional Water ◽  
Nitrate Supply ◽  
The Mean

The effect of fallowing before a wheat crop was studied in South Australia in an environment with suboptimal rainfall in the growing season. A 9–10 month pre-sowing fallow increased mean water storage (0–120 cm depth) at sowing by 28 mm, compared with a non-fallow soil preparation (2 month period of cultivation). Variation in additional storage ranged from nil to 125 mm. These amounts depended on soil type and season: in coarse-textured soils, fallowing conserved little additional water, but in fine-textured soils much additional water could be stored. Storage was not related to the summer rainfall (November-March) before sowing but was related to rainfall during July and August in the previous winter—just before or at the start of the fallow period. A combination of these two factors, fine-textured soil and good July–August rainfall, gave considerable storage. Fallowing also increased the nitrate nitrogen content in the surface 60 cm at sowing; the mean additional nitrogen amounted to 19 kg/ha in the coarse-textured soils and 30 kg/ha in the fine-textured soils. The largest increases due to fallowing were recorded in soils following medic leys and with ample rains on the fallow in spring. Comparison is made between these findings and those obtained with fallowing in other parts of Australia.

Observations and Modeling of Profile Soil Water Storage above a Shallow Water Table

2004 ◽  
Vol 68 (3) ◽  
pp. 719-724 ◽  
Author(s):  
Mahmood Nachabe ◽  
Caroline Masek ◽  
Jayantha Obeysekera
Keyword(s):  
Shallow Water ◽  
Soil Water ◽  
Water Table ◽  
Water Storage ◽  
Soil Water Storage ◽  
Shallow Water Table

scholarly journals The effect of changes in rainfall on the response of the water table to a major alley farming experiment

2009 ◽  
Vol 6 (3) ◽  
pp. 4563-4588
Author(s):  
S. L. Noorduijn ◽  
K. R. J. Smettem ◽  
R. Vogwill ◽  
A. Ghadouani
Keyword(s):  
Water Table ◽  
Land Degradation ◽  
Large Scale ◽  
Saline Water ◽  
Specific Yield ◽  
Annual Rainfall ◽  
Climate Trend ◽  
Alley Farming ◽  
Groundwater Levels ◽  
The Mean

Abstract. Widespread clearing of native vegetation in Southwest Western Australia has led to land degradation associated with rising groundwater, secondary salinisation and waterlogging. Land degradation can be controlled by re-establishing native deep rooted perennial vegetation across parts of the landscape. Alley farming is an agroforestry practice where multiple perennial tree belts are planted in alternation with traditional agricultural crops. To identify the best configuration (belt width verses alley width) for controlling rising groundwater levels and providing viable economic returns, a large scale experiment was established in 1995. The experiment contains seven different alley farming designs, each with transects of piezometers running across tree belts into adjacent alleys to monitor changes in the groundwater level. Two control piezometers were also installed in an adjacent paddock. At the site groundwater is shallow (<3 m) and of poor quality (pH 3–5, Ec 2.1–45.9 mS cm−1) and so root water uptake from the saturated zone is limited. Simple hydrograph analysis did not identify any treatment effects on the water table response. Subsequent statistical analysis revealed that 20–30% of the variability in the water table data over the 12 year period was attributable to the alley farming experiment. It was hypothesized that a climate trend (reducing annual rainfall over time) may be obscuring the effect of the experiment. To further investigate the effect of the experiment on groundwater response, further hydrograph analysis was conducted to compare the trends in the control piezometers in relation to those located within the belts. A difference of 0.9 m was observed between the mean groundwater levels in the control piezometers and the mean levels in the perennial belt piezometers. For a mean specific yield of 0.03 m3 m−3 this equates to a small additional water use of 27 mm yr−1 by the perennial agroforestry system. It is concluded that declining annual rainfall is the principal control on hydrograph response at the site. Perennial biomass development and perennial root development (both laterally and vertically) exert only a small influence on water table depth. The implications of this study indicate that alley farming has a limited ability to control a rising water table in low lying areas with a shallow saline water table.

Soil water changes under fallow-crop treatments in relation to soil type, rainfall and yield of wheat

1971 ◽  
Vol 11 (49) ◽  
pp. 236 ◽  
Author(s):  
JE Schultz
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Water Storage ◽  
South Australia ◽  
Soil Types ◽  
Soil Water Storage ◽  
Fallow Period ◽  
One Year ◽  
Water Contents ◽  
Soil Water Contents

Soil water changes under fallow (initial cultivation in spring), grassland (initial cultivation in autumn) and the succeeding wheat crops were recorded at two to three weekly intervals in three consecutive seasons in three soil types representing the range of wheat-growing soils in South Australia. Differences in water content between the two treatments developed soon after the start of fallowing due to the greater loss of water from grassland in spring. Rainfall during the fallow period contributed little to soil water storage except in one year when heavy spring rains were recorded. In some instances the water content in the fallowed soils at seeding was less than at the start of fallowing, but the fallowed soils consistently retained more water than the grassland soils. Soil water contents decreased after August of the crop year (end of tillering) and by harvest the wheat crops had commonly dried the soil to a depth of 150 cm. Fallow crops used more water and produced significantly higher wheat yields with a greater efficiency of water use in all trials.

scholarly journals Water table effects on measured and simulated fluxes in weighing lysimeters for differently-textured soils

2015 ◽  
Vol 63 (1) ◽  
pp. 82-92 ◽  
Author(s):  
Martin Wegehenkel ◽  
Horst H. Gerke
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Water Table ◽  
Sandy Soil ◽  
Water Storage ◽  
Soil Water Balance ◽  
Soil Water Storage ◽  
Silty Clay ◽  
Bottom Boundary ◽  
Soil Hydraulic

Abstract Weighing lysimeters can be used for studying the soil water balance and to analyse evapotranspiration (ET). However, not clear was the impact of the bottom boundary condition on lysimeter results and soil water movement. The objective was to analyse bottom boundary effects on the soil water balance. This analysis was carried out for lysimeters filled with fine- and coarse-textured soil monoliths by comparing simulated and measured data for lysimeters with a higher and a lower water table. The eight weighable lysimeters had a 1 m2 grass-covered surface and a depth of 1.5 m. The lysimeters contained four intact monoliths extracted from a sandy soil and four from a soil with a silty-clay texture. For two lysimeters of each soil, constant water tables were imposed at 135 cm and 210 cm depths. Evapotranspiration, change in soil water storage, and groundwater recharge were simulated for a 3-year period (1996 to 1998) using the Hydrus-1D software. Input data consisted of measured weather data and crop model-based simulated evaporation and transpiration. Snow cover and heat transport were simulated based on measured soil temperatures. Soil hydraulic parameter sets were estimated (i) from soil core data and (ii) based on texture data using ROSETTA pedotransfer approach. Simulated and measured outflow rates from the sandy soil matched for both parameter sets. For the sand lysimeters with the higher water table, only fast peak flow events observed on May 4, 1996 were not simulated adequately mainly because of differences between simulated and measured soil water storage caused by ET-induced soil water storage depletion. For the silty-clay soil, the simulations using the soil hydraulic parameters from retention data (i) were matching the lysimeter data except for the observed peak flows on May, 4, 1996, which here probably resulted from preferential flow. The higher water table at the lysimeter bottom resulted in higher drainage in comparison with the lysimeters with the lower water table. This increase was smaller for the finer-textured soil as compared to the coarser soil.

Soil water storage dynamics in peatlands with shallow water tables

2000 ◽  
Vol 80 (1) ◽  
pp. 43-52 ◽  
Author(s):  
David R. Lapen ◽  
Jonathan S. Price ◽  
Robert Gilbert
Keyword(s):  
Shallow Water ◽  
Soil Water ◽  
Water Table ◽  
Time Domain ◽  
Water Storage ◽  
Time Domain Reflectometry ◽  
Soil Water Storage ◽  
Shallow Water Table ◽  
Moisture Conditions ◽  
Peat Formation

Time domain reflectometry (TDR) was used to estimate soil water storage dynamics in several uncultivated blanket bogs and poor fens in southeastern Newfoundland during the summer growing season. The purpose of the research was to evaluate links between surface moisture conditions, evapotranspiration, and recharge processes in order to elucidate factors that govern blanket peat formation in the region. Water storage changes in the peat/Sphagnum above the water table (ΔSWS) were found to be important storage terms in daily water balance estimates. Daily mean ΔSWS values for bog and fen approximated −0.3 and −0.45 mm, respectively. It was also found that, i) fairly high peat water-holding capacities, ii) frequent atmospheric recharge, iii) atmospheric controls on evapotranspiration, and, iv) the transport of water into the unsaturated zone from the shallow water table via capillary and external wicking processes helped to preclude significant de-watering over the bulk of the peatland surfaces. Recharge via groundwater appears to be an important factor governing moisture conditions requisite for peat accrual and the growth of Sphagnum spp., especially in the fens. Key words: Time domain reflectometry, blanket peats, soil water, evapotranspiration, water table depth

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