scholarly journals Transformation Process of Five Water in Epikarst Zone: A Case Study in Subtropical Karst Area

2021 ◽  
Author(s):  
Tao Song ◽  
Liankai Zhang ◽  
Pengyu Liu ◽  
Shengzhang Zou ◽  
Yi Zhao ◽  
...  
Keyword(s):  
Soil Water ◽  
Conversion Rate ◽  
Overland Flow ◽  
Transformation Process ◽  
Karst Area ◽  
Evaporative Water ◽  
Vegetation Water ◽  
Low Efficiency ◽  
Fissure Water ◽  
Epikarst Zone

Abstract Five water stand for five forms existence models of water. In Karst area, Five water means precipitation, groundwater, evapotranspiration water, soil water, and overland flow. The complicated water-bearing hydrogeological media and the inhomogeneous water storage structure leads to low efficiency of water utilization. To reveal intricated water resources transformation in karst areas, a typical epikarst zone was selected. The Five water and their conversion processes were studied and the transformation models was built based on the long-term positioning observations. The results show that: (1) Overland flow can be generated when precipitation reaches 6 mm and lasts for 6 h. Under light and moderate rainfall (LMR) conditions, less than 6% of the precipitation is converted to overland flow. Under heavy rainfall and rainstorm (HRR) conditions, the conversion rate is 3.5%-6%. (2) Under the condition of LMR, there are 2%-3.5%, 40%-60% and 25%-35% that transformed to vegetation water, soil water and groundwater respectively, while it is 1.5%-2.2%, 25%-30% and 32%-50% under the condition of HRR. (3) The proportion of precipitation was transformed to soil water is 20%-70%. (4) The conversion rate of groundwater and karst fissure water for LMR conditions are 8%-15% and 10%-15%, and that for HRR is 15%- 20% and 20%-35%. (5) The proportions of different degrees of precipitation transformed into vegetation transpiration and evaporation water are 1.5%-3.5% and 6%-9%, respectively. (6) Generally, about 0%-4% of the precipitation is converted into overland flow, 20%-70% into soil water, 25%-50% into karst groundwater, and 1%-10% into evaporative water.

scholarly journals Factors Determining Soil Water Repellency in Two Coniferous Plantations on a Hillslope

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 730 ◽  
Author(s):  
Moein Farahnak ◽  
Keiji Mitsuyasu ◽  
Kyoichi Otsuki ◽  
Kuniyoshi Shimizu ◽  
Atsushi Kume
Keyword(s):  
Soil Water ◽  
Overland Flow ◽  
Soil Aggregates ◽  
Aggregate Size ◽  
Water Repellency ◽  
Soil Aggregate ◽  
Water Infiltration ◽  
Soil Water Repellency ◽  
Tree Cutting ◽  
Coniferous Plantations

Soil water repellency (SWR) is a cause of low water infiltration, overland flow and soil erosion in mountainous coniferous plantations in Japan. The factors determining SWR intensity were investigated in two coniferous plantations of Chamaecyparis obtusa (Siebold et Zucc.) Endl. and Cryptomeria japonica (L.f.) D. Don, using intact tree plots and cut tree plots on the same hillslope. The SWR of Ch. obtusa plots was stronger than that of Cr. japonica plots. SWR intensity decreased after tree cutting. There were no significant differences in SWR upslope and downslope of individual trees/stumps for both tree species, though areas downslope of individual Ch. obtusa trees had higher SWR intensity than those upslope. SWR intensity and soil aggregate stability were positively correlated in the Ch. obtusa intact tree plot (r = 0.88, p < 0.01), whereas in the cut tree plot, this correlation was weak with no significance (r = 0.29, p = 0.41). Soil aggregate size had a non-significant influence on SWR intensity. These findings suggest that SWR intensity was not related to the soil aggregate size, but SWR intensity seemed have a role in soil aggregation in the Ch. obtusa intact tree plot. Destruction of soil aggregates could occur after tree cutting because of physical disturbances or increased input of different types of organic matter from other vegetation into soil. The presence of Ch. obtusa introduces a source of SWR, although uncertainty remains about how water repellency is distributed around soil aggregates. The distribution pattern of soil water content and soil hydraulic conductivity around Cr. japonica was related to other factors such as the litter layer and non-water-repellant soil.

scholarly journals Response of soil water hydrochemistry and δ13CDIC to changes in spatio-temporal variations under different land covers in SW China karst catchment

2019 ◽  
Vol 50 (3) ◽  
pp. 925-944 ◽  
Author(s):  
Peng Wang ◽  
Licheng Shen ◽  
Xiaohong Chen ◽  
Zhijun Wang ◽  
Xuan Liang ◽  
...  
Keyword(s):  
Soil Water ◽  
Temporal Variations ◽  
Karst Area ◽  
Carbonate Content ◽  
Carbonate Dissolution ◽  
Soil Co2 ◽  
Dry Land ◽  
Dry Seasons ◽  
Land Covers ◽  
Spatio Temporal

Abstract Soil water plays a crucial role in biogeochemical processes within karst ecosystems. However, geochemical variations of soil waters under different land covers and the related karst critical zone processes are still unclear. In this study, five land covers, including grassland, dry land, shrub land, reforestation land, and bamboo land in the Qingmuguan karst area of Chongqing Municipality, Southwest (SW) China were investigated in order to better understand the spatio-temporal variations of soil water geochemistry and its controlling mechanisms. The hydrochemistry of soil water and stable carbon isotopic compositions of dissolved inorganic carbon (δ13CDIC) in soil water were analyzed by a semi-monthly sampling strategy. The results show that there is remarkable spatio-temporal variation in the hydrochemistry and δ13CDIC of soil waters under different land covers in the studied area. Soil waters collected from shrub, dry, and afforestation lands have higher total dissolved solids (TDS), Ca2+, and HCO3− concentrations and heavier δ13CDIC, which is probably associated with the stronger carbonate dissolution caused by higher soil CO2 and carbonate content in soils under these land covers. However, lower TDS, Ca2+, and HCO3− concentrations as well as δ13CDIC values but higher SO42− concentrations are found in soil waters collected from bamboo land and grassland. The reason is that higher gypsum dissolution or oxidation of sulfide minerals and less soil CO2 input occurs in soils under these two land covers. Under the shrub, dry, and afforestation lands, higher concentrations of Ca2+ and HCO3− in soil waters occur in rainy seasons than in dry seasons, which are probably linked to higher CO2 input due to stronger microbial activities and root respiration in the wet summer seasons. In addition, seasonal variations of NO3− concentrations in soil waters from the dry land are observed, and much higher NO3− concentration occurs in the rainy seasons than that in the dry seasons, which suggest that the agricultural fertilization may lead to high NO3− in soil water. On the vertical soil profile, except for the bamboo land, soil waters under different land covers commonly show an increasing trend of main ion concentrations with the increase of depth. This vertical variation of hydrochemistry and δ13CDIC values in soil waters is primarily controlled by the intensity of carbonate dissolution related to carbonate content in soils and soil CO2 production. The soil waters under different land covers have great variations in δ13CDIC values which ranged from −20.68‰ to −6.90‰. Also, the [HCO3−]/([Ca2+] + [Mg2+]), [NO3−]/[HCO3−], and [SO42−]/([Ca2+] + [Mg2+]) molar ratios in soil waters show a large amplitude of variation. This suggested that carbonic acids could not be a unique dissolving agent and sulfuric/nitric acids may play a role in the weathering of carbonate in the Qingmuguan karst area.

scholarly journals Seasonal changes of the soil hydrological and erosive response in contrasted Mediterranean eco-geomorphological conditions at patch scale

2013 ◽  
Vol 5 (2) ◽  
pp. 1423-1460 ◽  
Author(s):  
M. A. Gabarrón-Galeote ◽  
J. F. Martínez-Murillo ◽  
M. A. Quesada ◽  
J. D. Ruiz-Sinoga
Keyword(s):  
Soil Water ◽  
Seasonal Changes ◽  
Overland Flow ◽  
Hydrological Response ◽  
The South ◽  
Seasonal Behavior ◽  
Maximum Rainfall ◽  
Small Catchment ◽  
The North ◽  
Mediterranean Areas

Abstract. Mediterranean areas are characterized by a strong spatial variability that makes highly complex the soil hydrological response. Moreover, Mediterranean climate has a marked seasonal variability that provokes dramatic changes on the soil properties determining the hydrological behavior, such as soil water content, crust formation or soil water repellency (SWR). Thus, soil hydrological and erosive response in Mediterranean areas can be highly time- as well space-dependant. The main goal of this study was to characterize the relations between SWR, aspect and vegetation, determining the soil hydrological and erosive response throughout the rainy period in different microenvironments of opposite hillslopes. This study was undertaken in a small catchment located in the South of Spain. Erosion plots were installed in the north- and the south-facing hillslope, in areas with different vegetal cover, and runoff and sediments were collected. Moreover, precipitation parameters were recorded and SWR measurements were performed. SWR proved to have a significant effect on the soil hydrological response, but this influence was modulated by seasonal changes and by the discontinuities on the repellent layer. In general, the influence of SWR was restricted to the first rains after the summer and was greater on the north-facing hillslope due to the more continuous vegetation cover. The more important precipitation parameter influencing runoff generated was maximum rainfall intensity in ten minutes (Imax). The relation between Imax and overland flow showed a contrasting seasonal behavior in the north-facing hillslope and, on the contrary, remained homogeneous throughout the year in the south-facing hillslope.

scholarly journals Using Wastewater in Irrigation: The Effects on Infiltration Process in a Clayey Soil

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 968 ◽  
Author(s):  
Ammar A. Albalasmeh ◽  
Mamoun A. Gharaibeh ◽  
Ma’in Z. Alghzawi ◽  
Renato Morbidelli ◽  
Carla Saltalippi ◽  
...  
Keyword(s):  
Soil Water ◽  
Hydraulic Properties ◽  
Field Experiments ◽  
Overland Flow ◽  
Clayey Soil ◽  
Water Infiltration ◽  
Treated Wastewater ◽  
Water Drainage ◽  
Infiltration Process ◽  
Relevant Effect

Soil water infiltration is a critical process in the soil water cycle and agricultural practices, especially when wastewater is used for irrigation. Although research has been conducted to evaluate the changes in the physical and chemical characteristics of soils irrigated by treated wastewater, a quantitative analysis of the effects produced on the infiltration process is still lacking. The objective of this study is to address this issue. Field experiments previously conducted on three adjacent field plots characterized by the same clayey soil but subjected to three different irrigation treatments have been used. The three irrigation conditions were: non-irrigated (natural conditions) plot, irrigated plot with treated wastewater for two years, and irrigated plot with treated wastewater for five years. Infiltration measurements performed by the Hood infiltrometer have been used to estimate soil hydraulic properties useful to calibrate a simplified infiltration model widely used under ponding conditions, that were existing during the irrigation stage. Our simulations highlight the relevant effect of wastewater usage as an irrigation source in reducing cumulative infiltration and increasing overland flow as a result of modified hydraulic properties of soils characterized by a lower capacity of water drainage. These outcomes can provide important insights for the optimization of irrigation techniques in arid areas where the use of wastewater is often required due to the chronic shortage of freshwater.

scholarly journals Formation of runoff at the hillslope scale during intense precipitation

2006 ◽  
Vol 3 (4) ◽  
pp. 2523-2558 ◽  
Author(s):  
S. Scherrer ◽  
F. Naef ◽  
A. O. Faeh ◽  
I. Cordery
Keyword(s):  
Soil Water ◽  
Overland Flow ◽  
Subsurface Flow ◽  
Clay Content ◽  
Infiltration Rate ◽  
Soil Water Storage ◽  
Antecedent Soil Moisture ◽  
Near Surface ◽  
Soil Clay Content ◽  
A Site

Abstract. On 60 m2 hillslope plots at 18 mainly grassland locations in Switzerland rain was applied at rates of 50–100 mm/h for between 3 and 6 h. The generated flows were measured, overland flow near surface and subsurface flow in 0.5–1.3 m below surface. At some locations less than 2% of the rain flowed down the slope either on or below the surface, whereas at some others more than 90% of the rain ran off. At the majority of sites most runoff was overland flow, though at a few sites subsurface flow, usually via macropores was dominant. Data collected during each of 48 high intensity sprinkling experiments were used to distinguish which processes were dominant in each experiment. Which dominant and subsidiary processes occurred depended on interactions between infiltration rate, change in soil water storage and drainage of the soil water. These attributes were often not directly linked to parameters usually considered important like vegetation, slope, soil clay content and antecedent soil moisture. In many cases, process determination was fairly straightforward, indicating the possibility to reliably predict runoff processes at a site. However, at some sites, effects occurred that were not easily recognizable and led to surprising results.

scholarly journals Technical note: Evaporating water is different from bulk soil water in <i>δ</i><sup>2</sup>H and <i>δ</i><sup>18</sup>O and has implications for evaporation calculation

2021 ◽  
Vol 25 (10) ◽  
pp. 5399-5413
Author(s):  
Hongxiu Wang ◽  
Jingjing Jin ◽  
Buli Cui ◽  
Bingcheng Si ◽  
Xiaojun Ma ◽  
...  
Keyword(s):  
Soil Water ◽  
Technical Note ◽  
Soil Evaporation ◽  
Bulk Soil ◽  
Precipitation Event ◽  
Water Evaporation ◽  
Evaporation Time ◽  
Water Losses ◽  
Evaporative Water ◽  
Pore Size Distributions

Abstract. Soil evaporation is a key process in the water cycle and can be conveniently quantified using δ2H and δ18O in bulk surface soil water (BW). However, recent research shows that soil water in larger pores evaporates first and differs from water in smaller pores in δ2H and δ18O, which disqualifies the quantification of evaporation from BW δ2H and δ18O. We hypothesized that BW had different isotopic compositions from evaporating water (EW). Therefore, our objectives were to test this hypothesis first and then evaluate whether the isotopic difference alters the calculated evaporative water loss. We measured the isotopic composition of soil water during two continuous evaporation periods in a summer maize field. Period I had a duration of 32 d, following a natural precipitation event, and period II lasted 24 d, following an irrigation event with a 2H-enriched water. BW was obtained by cryogenically extracting water from samples of 0–5 cm soil taken every 3 d; EW was derived from condensation water collected every 2 d on a plastic film placed on the soil surface. The results showed that when event water was heavier than pre-event BW, δ2H of BW in period II decreased, with an increase in evaporation time, indicating heavy water evaporation. When event water was lighter than the pre-event BW, δ2H and δ18O of BW in period I and δ18O of BW in period II increased with increasing evaporation time, suggesting light water evaporation. Moreover, relative to BW, EW had significantly smaller δ2H and δ18O in period I and significantly smaller δ18O in period II (p<0.05). These observations suggest that the evaporating water was close to the event water, both of which differed from the bulk soil water. Furthermore, the event water might be in larger pores from which evaporation takes precedence. The soil evaporative water losses derived from EW isotopes were compared with those from BW. With a small isotopic difference between EW and BW, the evaporative water losses in the soil did not differ significantly (p>0.05). Our results have important implications for quantifying evaporation processes using water stable isotopes. Future studies are needed to investigate how soil water isotopes partition differently between pores in soils with different pore size distributions and how this might affect soil evaporation estimation.

Soil water repellency after wildfires in the Blue Ridge Mountains, United States

2020 ◽  
Vol 29 (11) ◽  
pp. 1009 ◽  
Author(s):  
Jingjing Chen ◽  
Luke A. Pangle ◽  
John P. Gannon ◽  
Ryan D. Stewart
Keyword(s):  
United States ◽  
Soil Water ◽  
Overland Flow ◽  
Water Repellency ◽  
Deciduous Forests ◽  
Organic Layer ◽  
Blue Ridge ◽  
Soil Water Repellency ◽  
Blue Ridge Mountains ◽  
Study Results

It is not well understood if wildfires induce soil water repellency in broadleaf deciduous forests, such as those endemic to the Blue Ridge Mountains of the eastern United States. In 2016, widespread wildfires provided an opportunity to study soil water repellency in this region. We selected sites in four locations with low to moderate burn severities, along with unburned controls. We estimated soil water repellency using water drop penetration time measurements from the surface (i.e. ash or organic) layer to ~5cm within the underlying mineral layer. Two months after the fires, water repellency was detected in all locations and was greater in more severely burned sites. One location had the greatest water repellency in surface ash (frequency of occurrence: 68–74%), whereas the other locations showed greatest repellency at the ash–mineral interface (40–96%). Unburned soils rarely showed repellency (0–18%). Burned soils also exhibited water repellency 1 year post fire. The study results suggest that combustion of non-resinous foliage within litter layers can cause water repellency in deciduous forests, meaning that this condition is not exclusive to coniferous and dryland forests. The duration of impact depends on fire severity, and may enhance overland flow and sediment transport in affected landscapes.

Impact of tile-drainage on the hydro-sedimentary responses of hydromorphic agricultural soils by tracing water and suspended solids from the field to the catchment scale.

2020 ◽  
Author(s):  
Arthur Gaillot ◽  
Célestine Delbart ◽  
Pierre Vanhooydonck ◽  
Olivier Cerdan ◽  
Sébastien Salvador-Blanes
Keyword(s):  
Soil Water ◽  
Suspended Solids ◽  
Overland Flow ◽  
Agricultural Soils ◽  
Subsurface Drainage ◽  
High Temporal Resolution ◽  
Field Scale ◽  
Catchment Scale ◽  
Surface Drainage ◽  
The Impact

&lt;p&gt;Since the 1960&amp;#8217;s, large landscape modifications were carried out to improve agriculture productivity. One of these changes was the ploughing of humid plains together with the installation of subsurface drainage, which currently represents 10 % of arable lands in the world. Studies have shown the impact of subsurface drainage on the water regime, and especially decreases in flow peaks. Drainage increases water and sediment connectivity. Less effort was devoted to investigate the impact on the erosion dynamics and very few studies were designed at the catchment scale. However, the understanding of water and suspended solids dynamics from field to catchment outlet is a key to set efficient conservation measures to reduce erosion up. Here we focus on water and suspended solids dynamics from the soil profile scale to the field scale. We propose to trace both water and suspended solids to determine the relative contributions between surface and subsurface sources. Water tracing gives indication on&amp;#160; pathways while suspended solids trace sources (i.e. soil surface vs. deeper soil). The study site is composed of a 5ha field within a 2500 ha agricultural catchment representative of the French agricultural intensive openfield catchments. The studied field is representative of the catchment. It is a cereal crops openfield. Two drainage methods exist in the field: subsurface drainage with drains 120 cm-deep and surface drainage with artificial channels created after the winter seeding. The soil in this field is a loamy clay soil with clay floor at 45 cm of depth. Quantification of suspended solids and water fluxes (surface and subsurface) are monitored at high temporal resolution both at the field (since January 2019) and catchment (since September 2013) scale. Since November 2019, we trace water flows (rain, soil water subsurface flow and overland flow) using water ions and stable isotopes. Suspended solids are analysed through their mineralogy and primary particle size. At the field scale, the first results show a rapid response of surface drainage to rain inputs - confirmed by ions tracing - and suspended solids are mainly coming from surface drainage. Subsurface drainage reacts with a significant delay. Ions tracing shows that subsurface runoff seems to result from a replacement of older soil water by rain inputs.&lt;/p&gt;

Data Analysis and Evaluation to Water-Sealed Underground Storage Cavern Water Curtain Efficiency Test

2015 ◽  
Vol 744-746 ◽  
pp. 956-961
Author(s):  
Jing Hua Liu ◽  
Sheng Nan Huang ◽  
Gang Chen
Keyword(s):  
Critical Pressure ◽  
Water Pressure ◽  
Hydrodynamic Condition ◽  
Efficiency Improvement ◽  
Analysis And Evaluation ◽  
Water Curtain ◽  
Low Efficiency ◽  
Efficiency Test ◽  
Fissure Water ◽  
Test Result

Water curtain efficiency test is the key method to evaluate the tightness and reliability of water curtain system. This thesis taking the cavern in Yantai as an example, based on the data of three different hydrodynamic condition stages during efficiency test, in combination with the important judgment parameter of water curtain efficiency-critical pressure value, the low efficiency of rock area was revealed by analyzing and evaluating the conduction effect of fissure water pressure. In order to improve the efficiency, drilled additional boreholes in low efficiency area. At last, through the test to evaluate efficiency improvement of new drilled boreholes. The test result shows that: the water curtain efficiency test can able to accurately determine the low efficiency area in rock mass, additional boreholes can significantly improve the pressure of low efficiency boreholes and can achieve the tightness requirements of cavern.

Comparison of the hydrological role of two reclaimed slopes of different ages in the Athabasca oil sands region, Alberta, Canada

2016 ◽  
Vol 53 (9) ◽  
pp. 1533-1546 ◽  
Author(s):  
Scott J. Ketcheson ◽  
Jonathan S. Price
Keyword(s):  
Soil Water ◽  
Surface Runoff ◽  
Oil Sands ◽  
Overland Flow ◽  
Water Storage ◽  
Infiltration Capacity ◽  
Athabasca Oil Sands ◽  
Athabasca Oil Sands Region ◽  
Over Time

Establishing hydrological connectivity in reconstructed landscapes, and understanding how this connectivity evolves over time, is critical for the development of effective water management strategies after oil sands extraction. In the current study, the dominant controls on the soil water regimes and runoff generation mechanisms on two contrasting reclaimed slopes (2 and 6 years after reclamation) in the Athabasca oil sands region are investigated. The most recently reclaimed slope demonstrated a hydrologic regime with limited soil water storage due to a low surface infiltration capacity that constrained percolation of rainfall. Accordingly, this slope generated a substantial amount of surface runoff controlled primarily by precipitation intensity. Conversely, the older slope had a greater surface infiltration capacity, more dynamic soil water regime, and infrequent surface runoff. Topography controlled soil water distribution on the older slope more strongly than the newer slope due to more efficient water redistribution. This suggests that changes in the hydrophysical properties of reclamation materials following construction result in a shift in the hydrological role of reclaimed slopes at the watershed scale. Thus, over time, reclaimed slopes produce less overland flow and shift from water conveyors to water storage features in constructed watershed systems.

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