scholarly journals Desiccation-crack-induced salinization in deep clay sediment

2013 ◽  
Vol 17 (4) ◽  
pp. 1533-1545 ◽  
Author(s):  
S. Baram ◽  
Z. Ronen ◽  
D. Kurtzman ◽  
C. Külls ◽  
O. Dahan
Keyword(s):  
Isotopic Composition ◽  
Conceptual Model ◽  
Pore Water ◽  
Vadose Zone ◽  
Land Surface ◽  
Water Infiltration ◽  
Arid Environments ◽  
Desiccation Cracks ◽  
The Impact ◽  
Desiccation Crack

Abstract. A study on water infiltration and solute transport in a clayey vadose zone underlying a dairy farm waste source was conducted to assess the impact of desiccation cracks on subsurface evaporation and salinization. The study is based on five years of continuous measurements of the temporal variation in the vadose zone water content and on the chemical and isotopic composition of the sediment and pore water in it. The isotopic composition of water stable isotopes (δ18O and δ2H) in water and sediment samples, from the area where desiccation crack networks prevail, indicated subsurface evaporation down to ~ 3.5 m below land surface, and vertical and lateral preferential transport of water, following erratic preferential infiltration events. Chloride (Cl−) concentrations in the vadose zone pore water substantially increased with depth, evidence of deep subsurface evaporation and down flushing of concentrated solutions from the evaporation zones during preferential infiltration events. These observations led to development of a desiccation-crack-induced salinization (DCIS) conceptual model. DCIS suggests that thermally driven convective air flow in the desiccation cracks induces evaporation and salinization in relatively deep sections of the subsurface. This conceptual model supports previous conceptual models on vadose zone and groundwater salinization in fractured rock in arid environments and extends its validity to clayey soils in semi-arid environments.

scholarly journals Desiccation-crack-induced salinization in deep clay sediment

2012 ◽  
Vol 9 (11) ◽  
pp. 13155-13189
Author(s):  
S. Baram ◽  
Z. Ronen ◽  
D. Kurtzman ◽  
C. Küells ◽  
O. Dahan
Keyword(s):  
Isotopic Composition ◽  
Conceptual Model ◽  
Pore Water ◽  
Vadose Zone ◽  
Land Surface ◽  
Water Infiltration ◽  
Arid Environments ◽  
Desiccation Cracks ◽  
The Impact ◽  
Desiccation Crack

Abstract. A study on water infiltration and solute transport in a clayey vadose zone underlying a dairy farm waste source was conducted to assess the impact of desiccation cracks on subsurface evaporation and salinization. The study is based on five years of continuous measurements of the temporal variation in the vadose zone water-content and on the chemical and isotopic composition of the sediment and pore-water in it. The isotopic composition of water stable isotopes (δ18O and δ2H) in water and sediment samples, from the area where desiccation crack networks prevail, indicated subsurface evaporation down to ∼3.5 m below land surface, and vertical and lateral preferential transport of water, following erratic preferential infiltration events. Chloride (Cl-) concentrations in the vadose zone pore water substantially increased with depth, evidence of deep subsurface evaporation and down flushing of concentrated solutions from the evaporation zones during preferential infiltration events. These observations led to development of a Desiccation-Crack-Induced Salinization (DCIS) conceptual model. DCIS suggests that thermally driven convective air flow in the desiccation cracks induces evaporation and salinization in relatively deep sections of the subsurface. This conceptual model supports previous conceptual models on vadose zone and groundwater salinization in fractured rock in arid environments and extends its validity to clayey soils in semi-arid environments.

IDENTIFIKASI BENCANA BANJIR KELURAHAN TLOGOSARI KECAMATAN PEDURUNGAN KOTA SEMARANG

Pondasi ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 94
Author(s):  
Andika Duwi Prasetyo ◽  
Agus Sarwo Edy Sudrajat
Keyword(s):  
Land Surface ◽  
Flood Control ◽  
Drainage System ◽  
Flood Disaster ◽  
Water Infiltration ◽  
Drainage Channel ◽  
Eastern Area ◽  
The People ◽  
The Impact ◽  
The City

ABSTRAK Bencana banjir di Kota Semarang sudah tak asing lagi bagi masyarakat Semarang, khususnya pada wilayah timur Kota Semarang, bencana banjir di Kota Semarang disebabkan beberapa faktor antara lain curah hujan yang tinggi, permukaan tanah yang lebih rendah dibandingkan permukaan air laut, dan banyaknya sampah yang tersumbat pada saluran drainase. Bencana banjir yang disebabkan oleh beberapa faktor tersebut berdampak buruk bagi Kota Semarang khususnya pada Kelurahan Tlogosari, Kecamatan Pedurungan, dampak dari bencana banjir tersebut mengakibatkan kerusakan pada jalan, kemacetan, dan dapat menyebabkan penyakit pada lingkungan di wilayah deliniasi di Kelurahan Tlogosari, Kecamatan Pedurungan. Perlu adanya penanganan untuk mengatasi bencana banjir di wilayah deliniasi Kelurahan Tlogosari, Kecamatan Pedurungan, seperti upaya melakukan pembangunan sistem pengendali banjir dan pada sistem drainase, dan pembangunan sumur resapan air pada setiap permukiman, serta melakukan konservasi secara berkala untuk sungai maupun sistem drainase di wilayah deliniasi Kelurahan Tlogosari, Kecamatan Pedurungan. Kata Kunci : Identifikasi; Banjir; Tlogosari ABSTRACT The flood disaster in Semarang City is familiar to the people of Semarang, especially in the eastern area of Semarang City, the flood disaster in Semarang City is caused by several factors, including high rainfall, lower land surface than sea level, and the amount of clogged garbage. on the drainage channel. The flood disaster caused by several of these factors had a bad impact on the city of Semarang, especially in Tlogosari Village, Pedurungan District, the impact of the flood disaster caused damage to roads, congestion, and could cause disease in the environment in the delineation area in Tlogosari Village, Pedurungan District. There is a need for handling to overcome flood disasters in the delineation area of Tlogosari Village, Pedurungan District, such as efforts to build a flood control system and drainage system, and build water infiltration wells in each settlement, as well as carry out periodic conservation of rivers and drainage systems in the delineation area. Tlogosari Village, Pedurungan District.Keyword: Identification;Flood; Tlogosari

Comparative study of the impact of two mechanical perforation densities on the behavior of a sandy soil

2012 ◽  
Vol 8 (1) ◽  
pp. 37-48
Author(s):  
S. Chehaibi ◽  
K. Abrougui ◽  
F. Haouala
Keyword(s):  
Soil Water ◽  
Sandy Soil ◽  
Water Infiltration ◽  
Cone Penetration ◽  
Initial State ◽  
Soil Water Infiltration ◽  
Good Improvement ◽  
The Impact ◽  
Positive Effect ◽  
Resistance To Penetration

The effects of mechanical perforation densities by extracting soil cores through an aerator Vertidrain with a working width of 1.6 m and equipped with hollow tines spaced of 65 mm, were studied on a sandy soil of a grassy sward in the Golf Course El Kantaoui in Sousse (Tunisia). The mechanical aeration was performed at two densities: 250 and 350 holes/m2. The cone penetration resistance and soil water infiltration were measured. These parameters were performed at initial state before aeration (E0) and then on the 10th, 20th and 30th day after aeration. These results showed that perforation density of 350 holes/m2 had a positive effect on the soil by reducing its cone resistance to penetration compared to the initial state (Rp = 14.8 daN/cm2). At 5 cm depth the decrease in resistance to penetration was 34% and 43% on the 10th and 20th day after aeration, respectively. However, on the 30th day after aeration the soil resistance to penetration tended to grow and its value compared to the initial state decreased only by 21 and 26%, respectively, at 5 and 15 cm of depth only by 10% and 9% with 250 holes/m2 density. The soil water infiltration made a good improvement after aeration compared to the initial state. This parameter increased from 4.8 cm/h to 8.3, 10.9 and 13.1 cm/h with 250 holes/m2 density and to 10, 12.9 and 14.8 cm/h with 350 holes/m2 density on the 10th, 20th and 30th day following the aeration.

Impact of LULC Changes on LST in Rajshahi District of Bangladesh: A Remote Sensing Approach

2020 ◽  
Vol 3 (1) ◽  
pp. 11-23 ◽  
Author(s):  
Abdulla Al Kafy ◽  
Abdullah Al-Faisal ◽  
Mohammad Mahmudul Hasan ◽  
Md. Soumik Sikdar ◽  
Mohammad Hasib Hasan Khan ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Surface Temperature ◽  
Land Surface ◽  
Agricultural Land ◽  
Global Climate ◽  
Urban Expansion ◽  
Water Bodies ◽  
Landsat 8 ◽  
Lulc Changes ◽  
The Impact

Urbanization has been contributing more in global climate warming, with more than 50% of the population living in cities. Rapid population growth and change in land use / land cover (LULC) are closely linked. The transformation of LULC due to rapid urban expansion significantly affects the functions of biodiversity and ecosystems, as well as local and regional climates. Improper planning and uncontrolled management of LULC changes profoundly contribute to the rise of urban land surface temperature (LST). This study evaluates the impact of LULC changes on LST for 1997, 2007 and 2017 in the Rajshahi district (Bangladesh) using multi-temporal and multi-spectral Landsat 8 OLI and Landsat 5 TM satellite data sets. The analysis of LULC changes exposed a remarkable increase in the built-up areas and a significant decrease in the vegetation and agricultural land. The built-up area was increased almost double in last 20 years in the study area. The distribution of changes in LST shows that built-up areas recorded the highest temperature followed by bare land, vegetation and agricultural land and water bodies. The LULC-LST profiles also revealed the highest temperature in built-up areas and the lowest temperature in water bodies. In the last 20 years, LST was increased about 13ºC. The study demonstrates decrease in vegetation cover and increase in non-evaporating surfaces with significantly increases the surface temperature in the study area. Remote-sensing techniques were found one of the suitable techniques for rapid analysis of urban expansions and to identify the impact of urbanization on LST.

scholarly journals Patient preferences for use of virtual consultations in an orthopaedic rehabilitation setting: Results from a discrete choice experiment

2021 ◽  
pp. 135581962110354
Author(s):  
Anthony W Gilbert ◽  
Emmanouil Mentzakis ◽  
Carl R May ◽  
Maria Stokes ◽  
Jeremy Jones
Keyword(s):  
Conceptual Model ◽  
Discrete Choice Experiment ◽  
Discrete Choice ◽  
Patient Preferences ◽  
Choice Experiment ◽  
Best Practice ◽  
Time Of Day ◽  
Problem Area ◽  
Fractional Factorial ◽  
The Impact

Objective Virtual Consultations may reduce the need for face-to-face outpatient appointments, thereby potentially reducing the cost and time involved in delivering health care. This study reports a discrete choice experiment (DCE) that identifies factors that influence patient preferences for virtual consultations in an orthopaedic rehabilitation setting. Methods Previous research from the CONNECT (Care in Orthopaedics, burdeN of treatmeNt and the Effect of Communication Technology) Project and best practice guidance informed the development of our DCE. An efficient fractional factorial design with 16 choice scenarios was created that identified all main effects and partial two-way interactions. The design was divided into two blocks of eight scenarios each, to reduce the impact of cognitive fatigue. Data analysis were conducted using binary logit regression models. Results Sixty-one paired response sets (122 subjects) were available for analysis. DCE factors (whether the therapist is known to the patient, duration of appointment, time of day) and demographic factors (patient qualifications, access to equipment, difficulty with activities, multiple health issues, travel costs) were significant predictors of preference. We estimate that a patient is less than 1% likely to prefer a virtual consultation if the patient has a degree, is without access to the equipment and software to undertake a virtual consultation, does not have difficulties with day-to-day activities, is undergoing rehabilitation for one problem area, has to pay less than £5 to travel, is having a consultation with a therapist not known to them, in 1 weeks’ time, lasting 60 minutes, at 2 pm. We have developed a simple conceptual model to explain how these factors interact to inform preference, including patients’ access to resources, context for the consultation and the requirements of the consultation. Conclusions This conceptual model provides the framework to focus attention towards factors that might influence patient preference for virtual consultations. Our model can inform the development of future technologies, trials, and qualitative work to further explore the mechanisms that influence preference.

scholarly journals Reservoir-Induced Land Deformation: Case Study from the Grand Ethiopian Renaissance Dam

2021 ◽  
Vol 13 (5) ◽  
pp. 874
Author(s):  
Yu Chen ◽  
Mohamed Ahmed ◽  
Natthachet Tangdamrongsub ◽  
Dorina Murgulet
Keyword(s):  
Land Surface ◽  
Large Scale ◽  
Surface Deformation ◽  
Vertical Displacement ◽  
Nile River ◽  
Reservoir Volume ◽  
Novel Approach ◽  
Land Deformation ◽  
Large Scale Land ◽  
The Impact

The Nile River stretches from south to north throughout the Nile River Basin (NRB) in Northeast Africa. Ethiopia, where the Blue Nile originates, has begun the construction of the Grand Ethiopian Renaissance Dam (GERD), which will be used to generate electricity. However, the impact of the GERD on land deformation caused by significant water relocation has not been rigorously considered in the scientific research. In this study, we develop a novel approach for predicting large-scale land deformation induced by the construction of the GERD reservoir. We also investigate the limitations of using the Gravity Recovery and Climate Experiment Follow On (GRACE-FO) mission to detect GERD-induced land deformation. We simulated three land deformation scenarios related to filling the expected reservoir volume, 70 km3, using 5-, 10-, and 15-year filling scenarios. The results indicated: (i) trends in downward vertical displacement estimated at −17.79 ± 0.02, −8.90 ± 0.09, and −5.94 ± 0.05 mm/year, for the 5-, 10-, and 15-year filling scenarios, respectively; (ii) the western (eastern) parts of the GERD reservoir are estimated to move toward the reservoir’s center by +0.98 ± 0.01 (−0.98 ± 0.01), +0.48 ± 0.00 (−0.48 ± 0.00), and +0.33 ± 0.00 (−0.33 ± 0.00) mm/year, under the 5-, 10- and 15-year filling strategies, respectively; (iii) the northern part of the GERD reservoir is moving southward by +1.28 ± 0.02, +0.64 ± 0.01, and +0.43 ± 0.00 mm/year, while the southern part is moving northward by −3.75 ± 0.04, −1.87 ± 0.02, and −1.25 ± 0.01 mm/year, during the three examined scenarios, respectively; and (iv) the GRACE-FO mission can only detect 15% of the large-scale land deformation produced by the GERD reservoir. Methods and results demonstrated in this study provide insights into possible impacts of reservoir impoundment on land surface deformation, which can be adopted into the GERD project or similar future dam construction plans.

scholarly journals Seasonal Variations of Daytime Land Surface Temperature and Their Underlying Drivers over Wuhan, China

2021 ◽  
Vol 13 (2) ◽  
pp. 323
Author(s):  
Liang Chen ◽  
Xuelei Wang ◽  
Xiaobin Cai ◽  
Chao Yang ◽  
Xiaorong Lu
Keyword(s):  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Maximum Temperature ◽  
Maximum Temperature Difference ◽  
Rapid Urbanization ◽  
The Impact ◽  
The City

Rapid urbanization greatly alters land surface vegetation cover and heat distribution, leading to the development of the urban heat island (UHI) effect and seriously affecting the healthy development of cities and the comfort of living. As an indicator of urban health and livability, monitoring the distribution of land surface temperature (LST) and discovering its main impacting factors are receiving increasing attention in the effort to develop cities more sustainably. In this study, we analyzed the spatial distribution patterns of LST of the city of Wuhan, China, from 2013 to 2019. We detected hot and cold poles in four seasons through clustering and outlier analysis (based on Anselin local Moran’s I) of LST. Furthermore, we introduced the geographical detector model to quantify the impact of six physical and socio-economic factors, including the digital elevation model (DEM), index-based built-up index (IBI), modified normalized difference water index (MNDWI), normalized difference vegetation index (NDVI), population, and Gross Domestic Product (GDP) on the LST distribution of Wuhan. Finally, to identify the influence of land cover on temperature, the LST of croplands, woodlands, grasslands, and built-up areas was analyzed. The results showed that low temperatures are mainly distributed over water and woodland areas, followed by grasslands; high temperatures are mainly concentrated over built-up areas. The maximum temperature difference between land covers occurs in spring and summer, while this difference can be ignored in winter. MNDWI, IBI, and NDVI are the key driving factors of the thermal values change in Wuhan, especially of their interaction. We found that the temperature of water area and urban green space (woodlands and grasslands) tends to be 5.4 °C and 2.6 °C lower than that of built-up areas. Our research results can contribute to the urban planning and urban greening of Wuhan and promote the healthy and sustainable development of the city.

The effect of the 2018 Giro d’Italia on Israel’s tourism firm value

2019 ◽  
Vol 25 (7) ◽  
pp. 1070-1083 ◽  
Author(s):  
Juan Luis Nicolau ◽  
Abhinav Sharma ◽  
Tal Zarankin
Keyword(s):  
Conceptual Model ◽  
Firm Value ◽  
Market Value ◽  
The Impact ◽  
First Time

On September 18, 2017, the organizers of the 2018 Giro d’Italia announced that for the first time in its history, this world famous event would begin outside of Europe—in Israel. This article contributes to the literature by taking advantage of this unique opportunity of analysis; in particular, it tests the effect that this announcement had upon Israeli tourism companies’ market value. The results show that on the very same day the announcement was made, there was an increment in the firm value of these companies. We propose a conceptual model and argue that the hype generated helps enhance the country’s image, leading to higher expectations of incoming tourism. This article presents a contribution to the growing evidence regarding the impact of such announcements upon actual market value of tourism companies.

Effect of Tillage Systems on Soil Organic Carbon and Soil Quality in a Purple Paddy Soil

2011 ◽  
Vol 183-185 ◽  
pp. 1190-1194
Author(s):  
Jun Ke Zhang ◽  
Qing Ju Hao ◽  
Chang Sheng Jiang ◽  
Yan Wu
Keyword(s):  
Organic Carbon ◽  
Soil Quality ◽  
Paddy Soil ◽  
Conventional Tillage ◽  
Water Infiltration ◽  
Purple Soil ◽  
Tillage Systems ◽  
Field Station ◽  
No Till ◽  
The Impact

The impact of conservation tillage practices on carbon sequestration has been of great interest in recent years. This experiment analyzed the organic carbon status of soils sampled at depth increments from 0 to 60 cm after 20 years in a purple paddy soil. The tillage experiment was established in the Key Field Station for Monitoring of Eco-Environment of Purple Soil of the Ministry of Agriculture of China, located in the farm of Southwest University (30°26′N, 106°26′E), Chongqing. In this paper, five tillage treatments including conventional tillage with rice only system (DP), conventional tillage with rotation of rice and rape system (SL), no-till and ridge culture with rotation of rice and rape system (LM), no-till and plain culture with rotation of rice and rape system (XM) and tillage and ridge culture with rotation of rice and rape system (LF) were selected as research objectives to measure SOC storage and stratification ratio of SOC (CSR). The SOC storage under different tillage systems was calculated based on an equivalent soil mass. The CSR can be used as an indicator of soil quality because surface organic matter is essential to erosion control, water infiltration, and the conservation of nutrients. Results showed that in soil under no-till SOC was concentrated near the surface, while in tilled soil SOC decreased equably with the increase of soil depth. The difference of SOC contents between the five tillage systems was the largest in the top soil and the lowest in the bottom soil. The order of SOC storage was LM (158.52 Mg C•ha-1) >DP (106.74 Mg C•ha-1) >XM (100.11 Mg C•ha-1) >LF (93.11 Mg C•ha-1) >SL (88.59 Mg C•ha-1), LM treatment was significantly higher than the other treatments. The CSR of 0-10/50-60 cm was 2.65, 2.70 and 2.14 under LM, XM and LF treatments, while 1.54 and 1.92 under DP and SL treatments. We considered CSR>2 indicate an improvement in soil quality produced by changing from tillage to no-tillage, as well as changing from plane to ridge. Overall, long-term LM treatment is a valid strategy for increasing SOC storage and improving soil quality in a purple paddy soil in Southwest China.

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