scholarly journals Ubiquitous Fractal Scaling and Filtering Behavior of Hydrologic Fluxes and Storages from A Mountain Headwater Catchment

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 613
Author(s):  
Ravindra Dwivedi ◽  
John F. Knowles ◽  
Christopher Eastoe ◽  
Rebecca Minor ◽  
Nathan Abramson ◽  
...  

We used the weighted wavelet method to perform spectral analysis of observed long-term precipitation, streamflow, actual evapotranspiration, and soil water storage at a sub-humid mountain catchment near Tucson, Arizona, USA. Fractal scaling in precipitation and the daily change in soil water storage occurred up to a period of 14 days and corresponded to the typical duration of relatively wet and dry intervals. In contrast, fractal scaling could be observed up to a period of 0.5 years in streamflow and actual evapotranspiration. By considering long-term observations of hydrologic fluxes and storages, we show that, in contrast to previous findings, the phase relationships between water balance components changed with component period and were not perfectly in or out of phase at all periods. Self-averaging behavior was apparent, but the temporal scales over which this behavior was applicable differed among the various water balance components. Conservative tracer analysis showed that this catchment acted as a fractal filter by transforming white noise in the precipitation input signal to a 1/f flicker in the streamflow output signal by means of both spatial and temporal subsurface advection and dispersion processes and soil wetting properties. This study provides an improved understanding of hydrological filtering behavior in mountain critical zones that are critical sources of water and ecosystem services throughout the world.

2010 ◽  
Vol 67 (1) ◽  
pp. 87-95 ◽  
Author(s):  
Durval Dourado-Neto ◽  
Quirijn de Jong van Lier ◽  
Klaas Metselaar ◽  
Klaus Reichardt ◽  
Donald R. Nielsen

The original Thornthwaite and Mather method, proposed in 1955 to calculate a climatic monthly cyclic soil water balance, is frequently used as an iterative procedure due to its low input requirements and coherent estimates of water balance components. Using long term data sets to establish a characteristic water balance of a location, the initial soil water storage is generally assumed to be at field capacity at the end of the last month of the wet season, unless the climate is (semi-) arid when the soil water storage is lower than the soil water holding capacity. To close the water balance, several iterations might be necessary, which can be troublesome in many situations. For (semi-) arid climates with one dry season, Mendonça derived in 1958 an equation to quantify the soil water storage monthly at the end of the last month of the wet season, which avoids iteration procedures and closes the balance in one calculation. The cyclic daily water balance application is needed to obtain more accurate water balance output estimates. In this note, an equation to express the water storage for the case of the occurrence of more than one dry season per year is presented as a generalization of Mendonça's equation, also avoiding iteration procedures.


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 ◽  
...  

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.


2016 ◽  
Vol 13 (1) ◽  
pp. 63-75 ◽  
Author(s):  
K. Imukova ◽  
J. Ingwersen ◽  
M. Hevart ◽  
T. Streck

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.


Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 143
Author(s):  
Marwan Kheimi ◽  
Shokry M. Abdelaziz

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.


2009 ◽  
Vol 13 (13) ◽  
pp. 1-22 ◽  
Author(s):  
Charles P-A. Bourque ◽  
Quazi K. Hassan

Abstract This paper explores the relationship between vegetation in the Liangzhou Oasis in the Upper Shiyang River watershed (USRW) of west-central Gansu, China, and within-watershed precipitation, soil water storage, and oasis self-support. Oases along the base of the Qilian Mountains receive a significant portion of their water supply (over 90%) from surface and subsurface flow originating from the Qilian Mountains. Investigation of vegetation control on oasis water conditions in the USRW is based on an application of a process model of soil water hydrology. The model is used to simulate long-term soil water content (SWC) in the Liangzhou Oasis as a function of (i) monthly composites of Moderate Resolution Imaging Spectroradiometer (MODIS) images of land surface and mean air temperature, (ii) spatiotemporal calculations of monthly precipitation and relative humidity generated with the assistance of genetic algorithms (GAs), and (iii) a 80-m-resolution digital elevation model (DEM) of the area. Modeled removal of vegetation is shown to affect within-watershed precipitation and soil water storage by reducing the exchange of water vapor from the land surface to the air, increasing the air’s lifting condensation level by promoting drier air conditions, and causing the high-intensity precipitation band in the Qilian Mountains to weaken and to be displaced upward, leading to an overall reduction of water to the Liangzhou Oasis.


2021 ◽  
Vol 25 (2) ◽  
pp. 945-956
Author(s):  
Yuan Gao ◽  
Lili Yao ◽  
Ni-Bin Chang ◽  
Dingbao Wang

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.


2021 ◽  
Author(s):  
Shengping Li ◽  
Guopeng Liang ◽  
Xueping Wu ◽  
Jinjing Lu ◽  
Erwan Plougonven ◽  
...  

Abstract. Drought is increasingly common due to frequent occurrences of extreme weather events, which further increases soil water repellency (SWR) and influences grain yield. Conservation agriculture is playing a vital role in attaining high food security and it could also increase SWR. However, the relationship between SWR and grain yield under conservation agriculture is still not fully understood. We studied the impact of SWR in 0–5 cm, 5–10 cm, and 10–20 cm layers during three growth periods on grain yield from a soil water availability perspective using a long-term field experiment. In particular, we assessed the effect of SWR on soil water content under two rainfall events with different rainfall intensities. Three treatments were conducted: conventional tillage (CT), reduced tillage (RT), and no-tillage (NT). The results showed that the water repellency index (RI) of NT and RT treatments in 0–20 cm layers was increased by 12.9 %–39.9 % and 5.7 %–18.2 % compared to CT treatment during the three growth periods, respectively. The effect of the RI on soil water content became more obvious with the decrease in soil moisture following rainfall, which was also influenced by rainfall intensity. The RI played a prominent role in increasing soil water storage during the three growth periods compared to the soil total porosity, penetration resistance, mean weight diameter, and organic carbon content. Furthermore, although the increment in the RI under NT treatment increased the soil water storage, grain yield was not influenced by RI (p > 0.05) because the grain yield under NT treatment was mainly driven by penetration resistance and least limiting water range (LLWR). The higher water sorptivity increased LLWR and water use efficiency, which further increased the grain yield under RT treatment. Overall, SWR, which was characterized by water sorptivity and RI, had the potential to influence grain yield by changing soil water availability (e.g. LLWR and soil water storage) and RT treatment was the most effective tillage management compared to CT and NT treatments in improving grain yield.


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