Management of excess water in duplex soils

1992 ◽  
Vol 32 (7) ◽  
pp. 857 ◽  
Author(s):  
DJ McFarlane ◽  
JW Cox
Keyword(s):  
Groundwater Recharge ◽  
Water Flow ◽  
Western Australia ◽  
Soil Structure ◽  
Wind Erosion ◽  
Growing Season ◽  
Water Levels ◽  
Storm Runoff ◽  
Cereal Crops ◽  
Excess Water

Excess water in duplex soils can be removed by drains. In soils in which drainage is impractical, some success has been obtained by deep ripping and by gypsum amendment. These practices can increase profile storage or drainage. Interceptor drains are suitable for duplex soils with slopes of more than about 1.5%. On more gentle slopes, relief drains are used to remove excess water. Subsurface tube and mole drains have been used successfully to drain cereal crops in Victoria, but in Western Australia open drains are preferred because they can carry storm runoff as well as seepage waters. The greatest cost of open drains is the land removed from production. Over 35% of the rain falling during the growing season has been removed by drains in Victoria and Western Australia in wet years. Drainage was almost entirely downslope of monitored interceptor drains in Western Australia, which is not predicted from the theory. Simulation of water levels between drains and of drain flows using the DRAINMOD model indicated significant, preferred pathways for water flow to drains. The pathways explain the predominantly downslope effect of interceptor drains and the wide drain spacings which can be used. Deep ripping and the incorporation of gypsum can reduce waterlogging in some soils, but has had no effect in several others. The effect of deep ripping on recharge is unclear. Drains may decrease groundwater recharge, water and wind erosion, and soil structure decline. Their effect on phosphate export from catchments is unclear.

Characterisation of a windbreak system on the south coast of Western Australia. 1. Microclimate and wind erosion

2002 ◽  
Vol 42 (6) ◽  
pp. 703 ◽  
Author(s):  
R. A. Sudmeyer ◽  
P. R. Scott
Keyword(s):  
Wind Speed ◽  
Western Australia ◽  
Wind Direction ◽  
Vapour Pressure ◽  
Wind Erosion ◽  
Vapour Pressure Deficit ◽  
Growing Season ◽  
Soil Movement ◽  
Air Temperatures ◽  
Prevailing Wind Direction

The lack of data relating changes in microclimate and wind erosion to crop growth in shelter is a constraint to the adoption of windbreak systems in Australia. In this experiment microclimate and soil movement were measured in a 450 m wide bay between 2 Pinus pinaster windbreaks in south-western Australia over 4 years. Changes in wind speed and microclimate as a result of wind shelter varied spatially and temporally. When the wind direction was perpendicular to the windbreaks, wind-run reductions greater than 20% extended 18 times the height of the windbreak (H) downwind. However, over the whole growing season wind-run reductions greater than 20% only extended 3–6 H from the windbreaks, and were confined to within 4 H over the whole year. Over the growing season, atmospheric vapour pressure and average daily temperature and potential evaporation in the most sheltered part of the windbreak bay were generally within ± 5–10% of unsheltered values. While growing conditions were generally improved, there were periods at the end of the growing season when sheltered crops experienced increased air temperatures and vapour pressure deficit. The principal benefit of the windbreaks appeared to be reducing wind speed during periods with short duration erosive winds. More than 1 H from the windbreaks, wind erosion was reduced for 36 H downwind of the windbreak that provided most shelter during the period of maximum soil movement. Browsing stock increased the porosity of the lower 1.5 m of the windbreaks, which allowed wind to funnel under the windbreaks. This study highlights the difficulty of maintaining constant shelter in an environment where the prevailing wind direction changes throughout the year and the need to orient windbreaks to provide shelter during those times when strong winds are most damaging to soils or crops.

Field-evaluation of DRAINMOD for predicting waterlogging intensity and drain performance in South-Western Australia

Soil Research ◽  
1994 ◽  
Vol 32 (4) ◽  
pp. 653 ◽  
Author(s):  
JW Cox ◽  
DJ Mcfarlane ◽  
RW Skaggs
Keyword(s):  
Groundwater Flow ◽  
Western Australia ◽  
Field Evaluation ◽  
Growing Season ◽  
Annual Rainfall ◽  
Cereal Crops ◽  
Soil Matrix ◽  
Field Point ◽  
Drain Flow

Waterlogging is common on sloping duplex soils in south-western Australia and causes damage to non-irrigated cereal crops and pastures. The factors which affect the performance of surface seepage interceptor drains installed to reduce this waterlogging are complex because the soils are very variable and have preferred pathways for groundwater flow. We compared DRAINMOD's predictions with field measured waterlogging intensity and drain flow over 3 years near Mt Barker and Narrogin in Western Australia. DRAINMOD failed to accurately predict waterlogging intensities and drain flows because water can move through macropores which bypass the soil matrix. At Mt Barker, DRAINMOD overpredicted waterlogging intensity by between 120% in a wet year and 650% in a very dry year. Drain flows were underpredicted by 148% in the driest year. At Narrogin, DRAINMOD underpredicted waterlogging intensity each year (rainfall was below average each year) and drain flow in the driest two years. However, by increasing Ks of the topsoil and adjusting Ks of the subsoil clay, DRAINMOD predictions agreed with measured responses. DRAINMOD can be used to predict waterlogging intensities and drain flows in duplex soils in the >450 mm annual rainfall areas of south-western Australia provided adjustments are made to the field point-measured Ks. Reliability increases with increasing rainfall during the growing season.

Ecosystem modeling of methane and carbon dioxide fluxes for boreal forest sites

2001 ◽  
Vol 31 (2) ◽  
pp. 208-223 ◽  
Author(s):  
Christopher Potter ◽  
Jill Bubier ◽  
Patrick Crill ◽  
Peter Lafleur
Keyword(s):  
Carbon Dioxide ◽  
Boreal Forest ◽  
Land Surface ◽  
Net Primary Production ◽  
Ground Cover ◽  
Methane Flux ◽  
Growing Season ◽  
Ecosystem Model ◽  
Heat Fluxes ◽  
Water Levels

Predicted daily fluxes from an ecosystem model for water, carbon dioxide, and methane were compared with 1994 and 1996 Boreal Ecosystem–Atmosphere Study (BOREAS) field measurements at sites dominated by old black spruce (Picea mariana (Mill.) BSP) (OBS) and boreal fen vegetation near Thompson, Man. Model settings for simulating daily changes in water table depth (WTD) for both sites were designed to match observed water levels, including predictions for two microtopographic positions (hollow and hummock) within the fen study area. Water run-on to the soil profile from neighboring microtopographic units was calibrated on the basis of daily snowmelt and rainfall inputs to reproduce BOREAS site measurements for timing and magnitude of maximum daily WTD for the growing season. Model predictions for daily evapotranspiration rates closely track measured fluxes for stand water loss in patterns consistent with strong controls over latent heat fluxes by soil temperature during nongrowing season months and by variability in relative humidity and air temperature during the growing season. Predicted annual net primary production (NPP) for the OBS site was 158 g C·m–2 during 1994 and 135 g C·m–2 during 1996, with contributions of 75% from overstory canopy production and 25% from ground cover production. Annual NPP for the wetter fen site was 250 g C·m–2 during 1994 and 270 g C·m–2 during 1996. Predicted seasonal patterns for soil CO2 fluxes and net ecosystem production of carbon both match daily average estimates at the two sites. Model results for methane flux, which also closely match average measured flux levels of –0.5 mg CH4·m–2·day–1 for OBS and 2.8 mg CH4·m–2·day–1 for fen sites, suggest that spruce areas are net annual sinks of about –0.12 g CH4·m–2, whereas fen areas generate net annual emissions on the order of 0.3–0.85 g CH4·m–2, depending mainly on seasonal WTD and microtopographic position. Fen hollow areas are predicted to emit almost three times more methane during a given year than fen hummock areas. The validated model is structured for extrapolation to regional simulations of interannual trace gas fluxes over the entire North America boreal forest, with integration of satellite data to characterize properties of the land surface.

scholarly journals Hurricane Effects on a Shallow Lake Ecosystem and Its Response to a Controlled Manipulation of Water Level

2001 ◽  
Vol 1 ◽  
pp. 44-70 ◽  
Author(s):  
Karl E. Havens ◽  
Kang-Ren Jin ◽  
Andrew J. Rodusky ◽  
Bruce Sharfstein ◽  
Mark A. Brady ◽  
...  
Keyword(s):  
Water Quality ◽  
Plant Communities ◽  
Large Scale ◽  
Growing Season ◽  
Water Levels ◽  
Surface Elevation ◽  
Submerged Plant ◽  
Lake Surface ◽  
The South ◽  
Water Depths

In order to reverse the damage to aquatic plant communities caused by multiple years of high water levels in Lake Okeechobee, Florida (U.S.), the Governing Board of the South Florida Water Management District (SFWMD) authorized a "managed recession" to substantially lower the surface elevation of the lake in spring 2000. The operation was intended to achieve lower water levels for at least 8 weeks during the summer growing season, and was predicted to result in a large-scale recovery of submerged vascular plants. We treated this operation as a whole ecosystem experiment, and assessed ecological responses using data from an existing network of water quality and submerged plant monitoring sites. As a result of large-scale discharges of water from the lake, coupled with losses to evaporation and to water supply deliveries to agriculture and other regional users, the lake surface elevation receded by approximately 1 m between April and June. Water depths in shoreline areas that historically supported submerged plant communities declined from near 1.5 m to below 0.5 m. Low water levels persisted for the entire summer. Despite shallow depths, the initial response (in June 2000) of submerged plants was very limited and water remained highly turbid (due at first to abiotic seston and later to phytoplankton blooms). Turbidity decreased in July and the biomass of plants increased. However, submerged plant biomass did not exceed levels observed during summer 1999 (when water depths were greater) until August. Furthermore, a vascular plant-dominated assemblage (Vallisnera, Potamogeton, and Hydrilla) that occurred in 1999 was replaced with a community of nearly 98% Chara spp. (a macro-alga) in 2000. Hence, the lake’s submerged plant community appeared to revert to an earlier successional stage despite what appeared to be better conditions for growth. To explain this unexpected response, we evaluated the impacts that Hurricane Irene may have had on the lake in the previous autumn. In mid-October 1999, this category 1 hurricane passed just to the south of the lake, with wind velocities over the lake surface reaching 90 km h-1 at their peak. Output from a three-dimensional hydrodynamic / sediment transport model indicates that during the storm, current velocities in surface waters of the lake increased from near 5 cm s-1to as high as 100 cm s-1. These strong velocities were associated with large-scale uplifting and horizontal transport of fine-grained sediments from the lake bottom. Water quality data collected after the storm confirmed that the hurricane resulted in lake-wide nutrient and suspended solids concentrations far in excess of those previously documented for a 10-year data set. These conditions persisted through the winter months and may have negatively impacted plants that remained in the lake at the end of the 1999 growing season. The results demonstrate that in shallow lakes, unpredictable external forces, such as hurricanes, can play a major role in ecosystem dynamics. In regions where these events are common (e.g., the tropics and subtropics), consideration should be given to how they might affect long-term lake management programs.

scholarly journals Partitioning CO<sub>2</sub> net ecosystem exchange fluxes on the microsite scale in the Lena River Delta, Siberia

2018 ◽  
Author(s):  
Tim Eckhardt ◽  
Christian Knoblauch ◽  
Lars Kutzbach ◽  
Gillian Simpson ◽  
Evgeny Abakumov ◽  
...  
Keyword(s):  
Water Table ◽  
Net Ecosystem Exchange ◽  
Growing Season ◽  
Arctic Tundra ◽  
High Water ◽  
Water Levels ◽  
River Delta ◽  
Lena River ◽  
Hydrological Conditions ◽  
Lena River Delta

Abstract. Arctic tundra ecosystems are currently facing rates of amplified climate change. This is critical as these ecosystems store significant amounts of carbon in their soils, which can be mineralized to CO2 and CH4 and released to the atmosphere. To understand how the CO2 net ecosystem exchange (NEE) fluxes will react to changing climatic conditions, it is necessary to understand the individual responses of the physiological processes contributing to CO2 NEE. Therefore, this study aimed: (i) to partition NEE fluxes at the soil-plant-atmosphere interface in an arctic tundra ecosystem; and (ii) to identify the main environmental drivers of these fluxes. Hereby, the NEE fluxes were partitioned into gross primary productivity (GPP) and ecosystem respiration (Reco) and further into autotrophic (RA) and heterotrophic respiration (RH). The study examined flux data collected during the growing season in 2015 using closed chamber measurements in a polygonal tundra landscape in the Lena River Delta, northeastern Siberia. The measured fluxes on the microscale (1 m–10 m) were used to model the NEE, GPP, Reco, RH, RA and net ecosystem production (NPP) over the growing season. Here, for the first time, the differing response of in situ measured RA and RH fluxes from permafrost-affected soils to hydrological conditions have been examined. It was shown that low RA fluxes are associated to a high water table, most likely due to the submersion of mosses, while an effect of water table fluctuations on RH fluxes was not observed. Furthermore, this work found the polygonal tundra in the Lena River Delta to be a sink for atmospheric CO2 during the growing season. Spatial heterogeneity was apparent with the net CO2 uptake at a wet, depressed polygon center being more than twice as high as that measured at a drier polygon rim. In addition to higher GPP fluxes, the differences in NEE between the two microsites were caused by lower Reco fluxes at the center compared to the rim. Here, the contrasting hydrological conditions caused the CO2 flux differences between the microsites, where high water levels lad to lower decomposition rates due to anoxic conditions.

The effect of raised beds on soil structure, waterlogging, and productivity on duplex soils in Western Australia

Soil Research ◽  
2005 ◽  
Vol 43 (5) ◽  
pp. 575 ◽  
Author(s):  
D. M. Bakker ◽  
G. J. Hamilton ◽  
D. J. Houlbrooke ◽  
C. Spann
Keyword(s):  
Western Australia ◽  
Soil Structure ◽  
Root Zone ◽  
Infiltration Rate ◽  
Climatic Conditions ◽  
Agricultural Crops ◽  
Yield Increase ◽  
Major Constraint ◽  
No Till ◽  
Poor Soil

Waterlogging and poor soil structure in the root-zone of duplex soils in Western Australia has long been recognised as a major constraint to the production of agricultural crops and pastures. The effect of raised beds on waterlogging, soil structure, and productivity of duplex soils was investigated. Five experimental sites were established, monitored, and operated over 5 years as well as 3 larger scale demonstration sites which were operated over 4 or 3 years. Treatments consisted of raised beds and a normal no-till seed bed as the control. The beds were made with a bed former after the soil had been deep cultivated. Bulk density and steady-state infiltration rate observations indicated significant and lasting improvements in soil structure in the beds. The incidence of waterlogging in raised beds was reduced and this was accompanied by an increase in runoff from the raised beds. The average grain yield increase from the beds was 18% for a variety of crops across a range of climatic conditions and duplex soils. Seven years after the introduction of raised beds for broad-acre farming in Western Australia, more than an estimated 30 000 ha of crops is now grown on raised beds.

scholarly journals Validation of the STRIVE model for coupling ecological processes and surface water flow

2010 ◽  
Vol 13 (4) ◽  
pp. 741-759
Author(s):  
L. De Doncker ◽  
P. Troch ◽  
R. Verhoeven ◽  
K. Buis ◽  
P. Meire
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Water Flow ◽  
Research Question ◽  
Quality Parameters ◽  
Water Levels ◽  
Ecological Processes ◽  
Vegetation Growth ◽  
Surface Water Flow ◽  
Quality Aspects

The 1D model package STRIVE is verified for simulating the interaction between ecological processes and surface water flow. The model is general and can be adapted and further developed according to the research question. The hydraulic module, based on the Saint-Venant equations, is the core part. The presence of macrophytes influences the water quality and the discharge due to the flow resistance of the river, expressed by Manning's coefficient, and allows an ecological description of the river processes. Based on the advection–dispersion equation, water quality parameters are incorporated and modelled. Calculation of the water quantity parameters, coupled with water quality and inherent validation and sensitivity analysis, is the main goal of this research. An important study area is the River Aa near Poederlee (Belgium), a lowland river with a wealth of vegetation growth, where discharge and vegetation measurements are carried out on a regular basis. The developed STRIVE model shows good and accurate calculation results. The work highlights the possibility of STRIVE to model flow processes, water quality aspects and ecological interaction combined and separately. Coupling of discharges, water levels, amount of biomass and tracer values provides a powerful prediction modelling tool for the ecological behaviour of lowland rivers.

scholarly journals Rule curve for seasonal increasing of water concessions in reservoirs with low regularized discharges

RBRH ◽  
2016 ◽  
Vol 21 (3) ◽  
pp. 493-501 ◽  
Author(s):  
Tereza Helena Costa Nunes ◽  
Carlos de Oliveira Galvão ◽  
Janiro Costa Rêgo
Keyword(s):  
Water Budget ◽  
High Water ◽  
Water Levels ◽  
Semiarid Region ◽  
Large Reservoir ◽  
Hydrological Variability ◽  
Excess Water ◽  
Brazilian Semiarid ◽  
Evaporation Losses ◽  
Rule Curve

ABSTRACT Regions with high hydrological variability are usually supplied by reservoirs that regularize discharges inter-annually, with low discharge of regularization, seasonally subject to large overflow and evaporation losses in their periods of high water levels. The Brazilian semiarid is one of such regions. This work looks at the possibility of using water that would be evaporated and/or spilled, in regions with such characteristics, to supply demands that would not be otherwise provided by the maximum legally allowed withdrawal discharge. The proposed method was applied to the operation of a large reservoir, located in the semiarid region of Brazil. Through simulation of the water budget and optimization, a rule curve was developed for reservoir operation for achieving the maximum exploitable reservoir withdrawal in rainy periods. The results show that it is possible to use the excess water in periods of large inflows with no damage to water supply during dry periods.

The effect of the variation of river water levels on the estimation of groundwater recharge in the Hsinhuwei River, Taiwan

2009 ◽  
Vol 59 (6) ◽  
pp. 1297-1307 ◽  
Author(s):  
Jung-Wei Chen ◽  
Hsun-Huang Hsieh ◽  
Hsin-Fu Yeh ◽  
Cheng-Haw Lee
Keyword(s):  
Groundwater Recharge ◽  
River Water ◽  
Water Levels
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