Deep infiltration - Significant or not

Soil Research ◽  
1989 ◽  
Vol 27 (2) ◽  
pp. 471
Author(s):  
J Brouwer
Keyword(s):  
Land Use ◽  
Water Balance ◽  
Soil Water ◽  
Water Storage ◽  
Soil Water Storage ◽  
Deep Drainage ◽  
Balance Problem ◽  
Deep Infiltration ◽  
Improved Pasture

For those involved with evaluating the effects on the water balance of changes in land use, it is always interesting and pleasing to see a report on a study involving paired catchments. One such report was presented by Prebble and Stirk (1988). From their study, Prebble and Stirk concluded that the killing of trees and establishment of improved pasture in an open grassy woodland did not affect evapotranspiration. While this result was not quite what they expected, they thought it could be explained by the fact that the killing of the trees resulted in an increase in wind run and in radiation to the grass. This in turn would have increased evapotranspiration from the grass, which would have compensated for the reduction in interception and evapotranspiration by the trees. This explanation, to some extent, ignores the observed increase in average soil water storage following the death of the trees. Perhaps, then, the answer to this water balance problem lies not in the evapotranspiration term, but in the increased soil water storage and associated increased deep drainage.

scholarly journals Mudanças no Uso da Terra e Efeito nos Componentes do Balanço Hídrico no Agreste Pernambucano

2020 ◽  
Vol 13 (2) ◽  
pp. 870
Author(s):  
Thyago Rodrigues do Carmo Brito ◽  
José Romualdo De Sousa Lima ◽  
Cássio Lopes de Oliveira ◽  
Rodolfo Marcondes Silva Souza ◽  
Antonio Celso Dantas Antonino ◽  
...  
Keyword(s):  
Land Use ◽  
Water Balance ◽  
Soil Water ◽  
Capillary Rise ◽  
Land Use Changes ◽  
Water Storage ◽  
Soil Water Storage ◽  
Water Balance Components ◽  
Water Losses ◽  
Regional Land

As mudanças no uso da terra podem provocar alterações no regime hídrico de várias regiões do mundo. Na região agreste de Pernambuco, essas mudanças consistem, principalmente, na retirada da Caatinga para a implantação de pastagens e culturas agrícolas. Contudo, pouco se sabe sobre o efeito dessas mudanças nos componentes do balanço hídrico. Desse modo, o objetivo do presente trabalho foi avaliar o efeito da conversão de áreas de Caatinga em áreas de pastagem nos componentes do balanço hídrico. Para isso, foram medidos, simultaneamente, o armazenamento de água no solo, os fluxos de água (drenagem e/ou ascensão capilar), o escoamento superficial e a evapotranspiração (ET) durante o período de 24 meses (outubro de 2013 a setembro de 2015), pela metodologia do balanço hídrico no solo, em áreas de Caatinga e de pastagem no município de São João-PE. Verificou-se que o armazenamento de água no solo na Caatinga foi menor que na pastagem, devido ao maior dossel e sistema radicular da Caatinga. As perdas de água por drenagem totalizaram -103,9 mm na pastagem e foram nulas na Caatinga. Em ambas as áreas a ET foi proporcional a precipitação pluvial. totalizando 1.195,6 mm com média de 1,64 mm d-1 na Caatinga e na pastagem totalizou 1.087,4 mm e 1,49 mm d-1. Conclui-se que as mudanças no uso da terra (retirada da Caatinga e implantação de pastagem) resultaram em aumento das perdas de água por drenagem e redução da evapotranspiração, que pode causar impacto no clima regional. Land Use Changes and Effects on the Water Balance Components in Agreste Pernambucano A B S T R A C TLand use changes can cause alterations in water regime in various regions of the world. In the Agreste region of Pernambuco, these changes consist mainly of the removal of Caatinga for the implantation of grassland and crops. However, little is known about the effect of these changes on water balance components. Thus, the objective of the present study was to evaluate the effect of the conversion of Caatinga areas into grassland in the water balance components. For this, we measured simultaneously the soil water storage, water fluxes (drainage and / or capillary rise), runoff and evapotranspiration (ET) over a 24-month period (October 2013 to September 2015), by the soil water balance method in Caatinga and grassland areas in São João-PE. It was found that the soil water storage in Caatinga was lower than in the grassland, due to the higher canopy and root system of the Caatinga. Water losses, via drainage, totaled -103.9 mm in the grassland and were zero in the Caatinga. In both areas, ET was proportional to rainfall, totaling 1,195.6 mm with an average of 1.64 mm d-1 in the Caatinga and in the grassland totaled 1,087.4 mm and 1.49 mm d-1. It concludes that land use changes (i.e., the conversion of Caatinga areas into grassland) resulted in increased losses of drainage and reduced evapotranspiration, which can impact on regional climate.Key words: Caatinga; grassland; evapotranspiration; soil water content.

Simulating the water balance of border-check irrigated pasture on a cracking soil

2004 ◽  
Vol 44 (2) ◽  
pp. 163 ◽  
Author(s):  
M. Bethune ◽  
Q. J. Wang
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Water Storage ◽  
Dairy Industry ◽  
Soil Water Storage ◽  
Deep Drainage ◽  
Annual Crop ◽  
Murray Darling Basin ◽  
Physically Based ◽  
Soil Cracks

The irrigated dairy industry relies on perennial pasture and is a major user of water in the Murray–Darling Basin of Australia. The sustainability of the irrigated dairy industry is threatened by high watertables and land salinisation. Options to alleviate these problems by reducing deep drainage are required. This paper assesses the potential to use the simulation model 'SWAP' to appraise options for reducing deep drainage. Minor modifications were made to SWAP so that it could simulate border-check irrigated pasture on a cracking soil. The model was tested against lysimeter data describing the water balance of irrigated pasture. Evapotranspiration, runoff, infiltration, soil water storage and deep drainage were well simulated when infiltration through soil cracks was modelled using the physically based approached in SWAP. Large errors in evapotranspiration, infiltration, runoff, soil water storage and deep drainage occurred when the process of infiltration through cracks was not simulated. Slight improvements in model predictions were achieved by specifying monthly crop factors, as opposed to a constant annual crop factor. However, a constant annual crop factor should be sufficiently accurate for most studies of deep drainage under border-check irrigated pastures.

scholarly journals Energy balance closure on a winter wheat stand: comparing the eddy covariance technique with the soil water balance method

2016 ◽  
Vol 13 (1) ◽  
pp. 63-75 ◽  
Author(s):  
K. Imukova ◽  
J. Ingwersen ◽  
M. Hevart ◽  
T. Streck
Keyword(s):  
Energy Balance ◽  
Water Balance ◽  
Winter Wheat ◽  
Water Content ◽  
Soil Water ◽  
Water Storage ◽  
Soil Water Balance ◽  
Soil Water Storage ◽  
Water Balance Method ◽  
Closure Method

Abstract. The energy balance of eddy covariance (EC) flux data is typically not closed. The nature of the gap is usually not known, which hampers using EC data to parameterize and test models. In the present study we cross-checked the evapotranspiration data obtained with the EC method (ETEC) against ET rates measured with the soil water balance method (ETWB) at winter wheat stands in southwest Germany. During the growing seasons 2012 and 2013, we continuously measured, in a half-hourly resolution, latent heat (LE) and sensible (H) heat fluxes using the EC technique. Measured fluxes were adjusted with either the Bowen-ratio (BR), H or LE post-closure method. ETWB was estimated based on rainfall, seepage and soil water storage measurements. The soil water storage term was determined at sixteen locations within the footprint of an EC station, by measuring the soil water content down to a soil depth of 1.5 m. In the second year, the volumetric soil water content was additionally continuously measured in 15 min resolution in 10 cm intervals down to 90 cm depth with sixteen capacitance soil moisture sensors. During the 2012 growing season, the H post-closed LE flux data (ETEC =  3.4 ± 0.6 mm day−1) corresponded closest with the result of the WB method (3.3 ± 0.3 mm day−1). ETEC adjusted by the BR (4.1 ± 0.6 mm day−1) or LE (4.9 ± 0.9 mm day−1) post-closure method were higher than the ETWB by 24 and 48 %, respectively. In 2013, ETWB was in best agreement with ETEC adjusted with the H post-closure method during the periods with low amount of rain and seepage. During these periods the BR and LE post-closure methods overestimated ET by about 46 and 70 %, respectively. During a period with high and frequent rainfalls, ETWB was in-between ETEC adjusted by H and BR post-closure methods. We conclude that, at most observation periods on our site, LE is not a major component of the energy balance gap. Our results indicate that the energy balance gap is made up by other energy fluxes and unconsidered or biased energy storage terms.

scholarly journals A Daily Water Balance Model Based on the Distribution Function Unifying Probability Distributed Model and the SCS Curve Number Method

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 143
Author(s):  
Marwan Kheimi ◽  
Shokry M. Abdelaziz
Keyword(s):  
Distribution Function ◽  
Water Balance ◽  
Soil Water ◽  
Storage Tank ◽  
Water Storage ◽  
Curve Number ◽  
Water Balance Model ◽  
Balance Model ◽  
Soil Water Storage ◽  
Daily Water

A new daily water balance model is developed and tested in this paper. The new model has a similar model structure to the existing probability distributed rainfall runoff models (PDM), such as HyMOD. However, the model utilizes a new distribution function for soil water storage capacity, which leads to the SCS (Soil Conservation Service) curve number (CN) method when the initial soil water storage is set to zero. Therefore, the developed model is a unification of the PDM and CN methods and is called the PDM–CN model in this paper. Besides runoff modeling, the calculation of daily evaporation in the model is also dependent on the distribution function, since the spatial variability of soil water storage affects the catchment-scale evaporation. The generated runoff is partitioned into direct runoff and groundwater recharge, which are then routed through quick and slow storage tanks, respectively. Total discharge is the summation of quick flow from the quick storage tank and base flow from the slow storage tank. The new model with 5 parameters is applied to 92 catchments for simulating daily streamflow and evaporation and compared with AWMB, SACRAMENTO, and SIMHYD models. The performance of the model is slightly better than HyMOD but is not better compared with the 14-parameter model (SACRAMENTO) in the calibration, and does not perform as well in the validation period as the 7-parameter model (SIMHYD) in some areas, based on the NSE values. The linkage between the PDM–CN model and long-term water balance model is also presented, and a two-parameter mean annual water balance equation is derived from the proposed PDM–CN model.

Simulation of the water balance for plants growing on coarse textured soils

Soil Research ◽  
1975 ◽  
Vol 13 (1) ◽  
pp. 21 ◽  
Author(s):  
BA Carbon ◽  
KA Galbraith
Keyword(s):  
Computer Simulation ◽  
Water Balance ◽  
Simulation Model ◽  
Close Agreement ◽  
Water Storage ◽  
Field Measurements ◽  
Soil Water Storage ◽  
Physical Parameters ◽  
Computer Simulation Model ◽  
Deep Drainage

A computer simulation model* of the water balance for plants growing on coarse soils was developed and tested against field measurements. The inputs for this model are measurable physical parameters. From the close agreement between simulated and observed results, it is suggested that evaporation, soil water storage and deep drainage may be satisfactorily predicted.

scholarly journals Diagnosis toward predicting mean annual runoff in ungauged basins

2021 ◽  
Vol 25 (2) ◽  
pp. 945-956
Author(s):  
Yuan Gao ◽  
Lili Yao ◽  
Ni-Bin Chang ◽  
Dingbao Wang
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Storage Capacity ◽  
Water Storage ◽  
Annual Runoff ◽  
Balance Model ◽  
Soil Water Storage ◽  
Ungauged Basins ◽  
Water Storage Capacity ◽  
Soil Water Storage Capacity

Abstract. Prediction of mean annual runoff is of great interest but still poses a challenge in ungauged basins. The present work diagnoses the prediction in mean annual runoff affected by the uncertainty in estimated distribution of soil water storage capacity. Based on a distribution function, a water balance model for estimating mean annual runoff is developed, in which the effects of climate variability and the distribution of soil water storage capacity are explicitly represented. As such, the two parameters in the model have explicit physical meanings, and relationships between the parameters and controlling factors on mean annual runoff are established. The estimated parameters from the existing data of watershed characteristics are applied to 35 watersheds. The results showed that the model could capture 88.2 % of the actual mean annual runoff on average across the study watersheds, indicating that the proposed new water balance model is promising for estimating mean annual runoff in ungauged watersheds. The underestimation of mean annual runoff is mainly caused by the underestimation of the area percentage of low soil water storage capacity due to neglecting the effect of land surface and bedrock topography. Higher spatial variability of soil water storage capacity estimated through the height above the nearest drainage (HAND) and topographic wetness index (TWI) indicated that topography plays a crucial role in determining the actual soil water storage capacity. The performance of mean annual runoff prediction in ungauged basins can be improved by employing better estimation of soil water storage capacity including the effects of soil, topography, and bedrock. It leads to better diagnosis of the data requirement for predicting mean annual runoff in ungauged basins based on a newly developed process-based model finally.

scholarly journals A stochastic approach for the description of the water balance dynamics in a river basin

2008 ◽  
Vol 12 (5) ◽  
pp. 1189-1200 ◽  
Author(s):  
S. Manfreda ◽  
M. Fiorentino
Keyword(s):  
Water Balance ◽  
Probability Density ◽  
Soil Water ◽  
Storage Capacity ◽  
Water Storage ◽  
Soil Water Balance ◽  
Soil Water Storage ◽  
Water Storage Capacity ◽  
Soil Water Storage Capacity ◽  
Balance Dynamics

Abstract. The present paper introduces an analytical approach for the description of the soil water balance dynamics over a schematic river basin. The model is based on a stochastic differential equation where the rainfall forcing is interpreted as an additive noise in the soil water balance. This equation can be solved assuming known the spatial distribution of the soil moisture over the basin transforming the two-dimensional problem in space in a one dimensional one. This assumption is particularly true in the case of humid and semihumid environments, where spatial redistribution becomes dominant producing a well defined soil moisture pattern. The model allowed to derive the probability density function of the saturated portion of a basin and of its relative saturation. This theory is based on the assumption that the soil water storage capacity varies across the basin following a parabolic distribution and the basin has homogeneous soil texture and vegetation cover. The methodology outlined the role played by the soil water storage capacity distribution of the basin on soil water balance. In particular, the resulting probability density functions of the relative basin saturation were found to be strongly controlled by the maximum water storage capacity of the basin, while the probability density functions of the relative saturated portion of the basin are strongly influenced by the spatial heterogeneity of the soil water storage capacity. Moreover, the saturated areas reach their maximum variability when the mean rainfall rate is almost equal to the soil water loss coefficient given by the sum of the maximum rate of evapotranspiration and leakage loss in the soil water balance. The model was tested using the results of a continuous numerical simulation performed with a semi-distributed model in order to validate the proposed theoretical distributions.

Elucidating soil moisture dynamics in agricultural landscapes under varying weather patterns

2021 ◽  
Author(s):  
Veronica Fritz ◽  
Thakshajini Thaasan ◽  
Andrew Williams ◽  
Ranjith Udawatta ◽  
Sidath Mendis ◽  
...  
Keyword(s):  
Land Use ◽  
Soil Moisture ◽  
Soil Water ◽  
Water Cycle ◽  
Water Storage ◽  
Soil Water Storage ◽  
Storm Events ◽  
Weather Patterns ◽  
Land Use Types ◽  
Moisture Dynamics

<p>Changing weather patterns and anthropogenic land use change significantly alter the terrestrial water cycle. A key variable that modulates the water cycle on the land surface is soil moisture and its variability in time and space. Hydrological models are used to simulate key components of the water cycle including infiltration, soil storage and uptake by plants. However, uncertainties remain in accurately representing soil moisture dynamics in models. Here, with the aid of several sensors installed at a 30-ha experimental research facility, we attempt to quantify differences in soil water storage across multiple land use types – cropped area, mosaic of turf grass and native plants, and an unkept weeded area as control land use. We will also discuss the accuracy of sensors to correctly measure soil water storage. Our study was conducted at an agricultural experimental station in Columbia, Missouri, USA. We use a variety of instruments to measure weather, evapotranspiration, and soil water. We used boundary layer scintillometers to measure near-surface turbulence, sensors to continuously track soil moisture and temperature, as well as weather stations for precipitation, air temperature, solar radiation and wind speed.  Changes in volumetric water content and soil temperature are measured at 5-minute intervals at 10-, 20-, and 40-cm soil depths to compare soil water storage among the three land use types. We also took soil samples before and after several storm events to calibrate the sensor readings at three sites. We, then, analyzed several storm events over a period of five months and compared the actual soil moisture and soil temperature dynamics at finer time intervals. With additional measurements of weather and boundary layer turbulence, we hope to reveal the landscape and weather control on soil moisture distribution across multiple land uses, and their subsequent impact on plant water uptake. Our preliminary results indicate that continuously disturbed agricultural lands depletes soil moisture at faster rates, which may present challenges in maintaining land productivity in the long term.</p>

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