ANALYSIS OF SUCTION DISTRIBUTION RESPONSE TO RAINFALL EVENT AND TREE CANOPY

2016 ◽  
Vol 78 (8-5) ◽  
Author(s):  
Mohd FakhrurazziIshak ◽  
Nazri Ali ◽  
Azman Kassim
Keyword(s):  
Matric Suction ◽  
Field Monitoring ◽  
Rainfall Event ◽  
Tree Canopy ◽  
Dominant Factor ◽  
Residual Soil ◽  
Initial Condition ◽  
Canopy Interception ◽  
Rainfall Events ◽  
Sloping Surface

This study provides an exploration of matric suction influenced by tree canopy interception on a single rainfall event. A field monitoring was carried out to measure matric suction at slope with two conditions; at toe of slope without tree and with a tree at toe of slope on a tropical residual soil. The variation in matric suction values and matric suction profiles response to the rainfall events on slope with and without a tree at toe were analysed to reveal the effect of the tree canopy. At initial condition, the matric suction was significantly higher at vicinity of tree compared to that of area without tree at toe of slope. However, a typical short and intense tropical rainfall has caused the matric suction to drop dramatically to a minimum value on slope without tree. This condition did not occur on slope with tree. Although, both slopes (with and without tree at toe) received the same amount of precipitation rainfall but the different responses in matric suction valueswere clearly shown at slope with tree at the slope toe. The short and intense rainfalls appeared to be the dominant factor to the suction variation at slope without tree, but not at slope with the tree. The tree canopy can be a factor to influence the suction variation at slope with tree as canopy interception reduced the amount of precipitation to the ground/sloping surface

scholarly journals Characteristics of rainfall events in regional climate model simulations for the Czech Republic

2017 ◽  
Vol 21 (2) ◽  
pp. 963-980 ◽  
Author(s):  
Vojtěch Svoboda ◽  
Martin Hanel ◽  
Petr Máca ◽  
Jan Kyselý
Keyword(s):  
Czech Republic ◽  
Regional Climate Model ◽  
Climate Model ◽  
Regional Climate ◽  
Rainfall Event ◽  
Spatial Average ◽  
Total Precipitation ◽  
Rainfall Events ◽  
The Czech Republic ◽  
Simulated Event

Abstract. Characteristics of rainfall events in an ensemble of 23 regional climate model (RCM) simulations are evaluated against observed data in the Czech Republic for the period 1981–2000. Individual rainfall events are identified using the concept of minimum inter-event time (MIT) and only heavy events (15 % of events with the largest event depths) during the warm season (May–September) are considered. Inasmuch as an RCM grid box represents a spatial average, the effects of areal averaging of rainfall data on characteristics of events are investigated using the observed data. Rainfall events from the RCM simulations are then compared to those from the at-site and area-average observations. Simulated number of heavy events and seasonal total precipitation due to heavy events are on average represented relatively well despite the higher spatial variation compared to observations. RCM-simulated event depths are comparable to the area-average observations, while event durations are overestimated and other characteristics related to rainfall intensity are significantly underestimated. The differences between RCM-simulated and at-site observed rainfall event characteristics are in general dominated by the biases of the climate models rather than the areal-averaging effect. Most of the rainfall event characteristics in the majority of the RCM simulations show a similar altitude-dependence pattern as in the observed data. The number of heavy events and seasonal total precipitation due to heavy events increase with altitude, and this dependence is captured better by the RCM simulations with higher spatial resolution.

Infiltration characteristics of two instrumented residual soil slopes

2003 ◽  
Vol 40 (5) ◽  
pp. 1012-1032 ◽  
Author(s):  
Illias Tsaparas ◽  
Harianto Rahardjo ◽  
David G Toll ◽  
Eng-Choon Leong
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Field Measurements ◽  
Residual Soil ◽  
Rainfall Runoff ◽  
Rainfall Events ◽  
Pore Water Pressures ◽  
Soil Slopes ◽  
Pressure Changes

This paper presents the analysis of a 12 month long field study of the infiltration characteristics of two residual soil slopes in Singapore. The field measurements consist of rainfall data, runoff data of natural and simulated rainfall events, and pore-water pressure changes during infiltration at several depths and at several locations on the two slopes. The analysis of the field measurements identifies the total rainfall and the initial pore-water pressures within the two slopes as the controlling parameters for the changes in the pore-water pressures within the slopes during infiltration.Key words: infiltration, rainfall, runoff, pore-water pressure, field measurements.

Modelling of suspended sediment in a weir reach using EFDC model

2015 ◽  
Vol 73 (7) ◽  
pp. 1583-1590 ◽  
Author(s):  
Gijung Pak ◽  
Kristine Joy B. Mallari ◽  
Jongrak Baek ◽  
Deokwoo Kim ◽  
Hwansuk Kim ◽  
...  
Keyword(s):  
Water Quality ◽  
Suspended Solids ◽  
Water Quality Management ◽  
Total Suspended Solids ◽  
Rainfall Event ◽  
Hydraulic Structures ◽  
Rainfall Events ◽  
Efdc Model ◽  
Environmental Fluid ◽  
Modelling System

Construction of hydraulic structures often leads to alteration of river dynamics and water quality. Suspended solids entering the upstream of the weir cause adverse effects to the hydroecological system and, therefore, it is necessary to build a modelling system to predict the changes in the river characteristics for proper water quality management. In this study, the discharges and total suspended solids upstream and downstream of the Baekje Weir installed in Geum River, Korea, was modelled using the environmental fluid dynamics code (EFDC) model. The resulting trend of four rainfall events shows that as rainfall increases, the total suspended solids (TSS) concentration increases as well. For the two larger events, at the upstream of the weir, TSS was observed to decrease or remain constant after the rainfall event depending on the lowering of the open gate. At the downstream, TSS supply was controlled by the weir during and after the rainfall event resulting in decline in the TSS concentration. The modelling produced good results for discharge based on %Diff. (4.37–6.35), Nash–Sutcliffe efficiency (NSE) (0.94–0.99) and correlation coefficient (r) (0.97–0.99) values as well as for TSS with acceptable values for %Diff. (12.08–14.11), NSE (0.75–0.81) and r (0.88–0.91), suggesting good applicability of the model for the weir reach of the river in the study site.

Monitored and simulated variations in matric suction during rainfall in a residual soil slope

2007 ◽  
Vol 55 (5) ◽  
pp. 951-961 ◽  
Author(s):  
Aurelian C. Trandafir ◽  
Roy C. Sidle ◽  
Takashi Gomi ◽  
Toshitaka Kamai
Keyword(s):  
Matric Suction ◽  
Residual Soil ◽  
Soil Slope ◽  
Residual Soil Slope

Rate of strength increase of unsaturated lateritic soil

2008 ◽  
Vol 45 (9) ◽  
pp. 1335-1343 ◽  
Author(s):  
Meen-Wah Gui ◽  
Chun-Ming Yu
Keyword(s):  
Shear Strength ◽  
Failure Criterion ◽  
Matric Suction ◽  
Slope Instability ◽  
Lateritic Soil ◽  
Strength Increase ◽  
Residual Soil ◽  
Strength Tests ◽  
Soil Shear Strength ◽  
Intact Soil

Lateritic soil is a kind of residual soil that is widely distributed in Asia. The water table of the soil is normally very deep so the upper part of the soil is often unsaturated. The largest lateritic soil area in Taiwan is the Linkou terrace. Because the soil here is loosely cohered and consolidated, the problem of slope instability and landslides has always been a major concern. To evaluate the triggering mechanism of landslides, it is necessary to obtain the failure criterion that represents both the saturated and unsaturated conditions of the soil before any analysis is carried out. The parameter required to define such a failure criterion is the rate of shear strength increase, tan φb, which can be obtained via a series of laboratory strength tests in a modified triaxial system under various matric suction levels. Both the intact and remolded lateritic soils taken from Linkou terrace have been tested for this purpose. The results confirm that matric suction in the lateritic soil contributes significantly to the soil shear strength and that intact soil has a higher strength than remolded soil.

scholarly journals Evolution of physicochemical species concentration in streams based on heavy rainfall event data obtained for high-frequency monitoring

RBRH ◽  
2016 ◽  
Vol 21 (4) ◽  
pp. 653-665
Author(s):  
Rubia Girardi ◽  
Adilson Pinheiro ◽  
Edson Torres ◽  
Vander Kaufmann ◽  
Luis Hamilton Pospissil Garbossa
Keyword(s):  
Water Quality ◽  
Water Level ◽  
Atlantic Forest ◽  
High Frequency ◽  
Heavy Rainfall ◽  
Rainfall Event ◽  
Heavy Rainfall Event ◽  
Rainfall Events ◽  
Frequency Monitoring ◽  
Heavy Rainfall Events

ABSTRACT Studies carried out over short time intervals assist in understanding the biogeochemical processes occurring relatively fast in natural waters. High frequency monitoring shows a greater variability in the water quality during and immediately after heavy rainfall events. This paper presents an assessment of the surface water quality parameters in the Atlantic Forest biome, caused by heavy rainfall events. The work was developed in two fluviometric sections of the Concordia River watershed, located in the state of Santa Catarina, southern Brazil. The spatial distribution of land use shows the predominance of Atlantic Forest in fluviometric section 1 (FS1) and pasture, forestry, agriculture, and Atlantic Forest in fluviometric section 2 (FS2). In each selected heavy rainfall event, the evolution rainfall height, the water level, and physicochemical parameters of water were analyzed. In all events, the water quality changed due to the heavy rainfall. After the events, an increase in water level and turbidity in both fluviometric sections were detected. In addition, the ammonium ion concentration increased in the river, and the pH value and nitrate concentration decreased. The electrical conductivity presented different behavior in each section. The dissolved oxygen concentration increased in 19 of 27 events. The principal component (PC1) correlated with the turbidity in FS1, and it correlated with level, turbidity, and pH in FS2.

scholarly journals Impacts of wildfire and post-fire land management on hydrological and sediment processes in a humid Mediterranean headwater catchment

2021 ◽  
Author(s):  
Joao Pedro Nunes ◽  
Léonard Bernard-Jannin ◽  
María Luz Rodríguez-Blanco ◽  
Anne-Karine Boulet ◽  
Juliana Marisa Santos ◽  
...  
Keyword(s):  
Sediment Yield ◽  
Agricultural Landscape ◽  
Sediment Concentration ◽  
Dominant Factor ◽  
Severe Drought ◽  
Negative Consequences ◽  
Catchment Scale ◽  
Burnt Area ◽  
Rainfall Events ◽  
The North

<p>The extensive afforestation of the Mediterranean rim of Europe in recent decades has increased the number of wildfire disturbances on hydrological and sediment processes, but the impacts on headwater catchments is still poorly understood, especially when compared with the previous agricultural landscape. This work monitored an agroforestry catchment in the north-western Iberian Peninsula, with plantation forests mixed with traditional agriculture using soil conservation practices, for one year before the fire and for three years afterwards, during which period the burnt area was plowed and reforested. During this period, continuous data was collected for meteorology, streamflow and sediment concentration at the outlet, erosion features were mapped and measured after major rainfall events, and channel sediment dynamics were monitored downstream from the agricultural and the burnt forest area. Data from 202 rainfall events with over 10 mm was analysed in detail.</p><p>Results show that the fire led to a notable impact on sediment processes during the first two post-fire years, but not on streamflow processes; this despite the small size of the burnt area (10% of the catchment) and the occurrence of a severe drought in the first year after the fire. During this period, soil loss at the burnt forest slopes was much larger than that at most traditionally managed fields, and, ultimately, led to sediment exhaustion. At the catchment scale, storm characteristics were the dominant factor behind streamflow and sediment yield both before and after the fire. However, the data indicated a shift from detachment-limited sediment yield before the fire, to transport-limited sediment yield afterwards, with important increases in streamflow sediment concentration. This indicates that even small fires can temporarily change sediment processes in agroforestry catchments, with potential negative consequences for downstream water quality.</p>

scholarly journals Stem Flow, Throughfall, and Canopy Interception of Rainfall by Citrus Tree Canopies

HortScience ◽  
1997 ◽  
Vol 32 (6) ◽  
pp. 1059-1160 ◽  
Author(s):  
Y.C. Li ◽  
A.K. Alva ◽  
D.V. Calvert ◽  
M. Zhang
Keyword(s):  
Tree Canopy ◽  
Storm Event ◽  
Citrus Paradisi ◽  
Citrus Tree ◽  
Canopy Interception ◽  
Canopy Effect ◽  
Tree Canopies ◽  
Stem Flow ◽  
Citrus Cultivar ◽  
Rain Events

It is generally believed that the interception of rain by the citrus tree canopy can substantially decrease the throughfall under the canopy as compared to that along the dripline or outside the canopy (incident rainfall). Therefore, the position of placement of soil-applied agrichemicals in relation to the tree canopy may be an important consideration to minimize their leaching during rain events. In this study, the distributions of rainfall under the tree canopies of three citrus cultivars, `Marsh' grapefruit (Citrus paradisi Macf.), `Hamlin' orange (Citrus sinensis L. Osbeck), and `Temple' orange (Citrus hybrid), were evaluated at four directions (north, south, east, west), two positions (dripline and under the canopy), and stem flow. There was not a significant canopy effect on rainfall amounts from stem flow or dripline, compared with outside canopy, for any citrus cultivar or storm event. However, throughfall varied significantly among the four cardinal directions under the canopy of all three citrus cultivars and was highly related to the wind direction. Among the three citrus cultivars evaluated in this study, throughfall, stem flow, and canopy interception accounted for 89.5% to 92.7%, 0.5% to 4.7%, and 5.8% to 9.3% of the incident rainfall, respectively.

scholarly journals Impact of a high rainfall event on the water level, current velocity, and total suspended solids in tidal flats environments of the estuarine Cruces River wetland, south-central Chile

2021 ◽  
Vol 49 (1) ◽  
pp. 188-192
Author(s):  
Mario Manzano ◽  
Eduardo Jaramillo ◽  
Mario Pino
Keyword(s):  
Surface Waters ◽  
Suspended Solids ◽  
Environmental Variability ◽  
Total Suspended Solids ◽  
Tidal Flats ◽  
Rainfall Event ◽  
Rainfall Events ◽  
Central Chile ◽  
South Central ◽  
Coseismic Subsidence

The effects of a sudden rainfall (40 mm d-1) event on the surface waters covering muddy tidal flats were studied during April 2016 at the estuarine Cruces River wetland in south-central Chile (~40ºS). The study area included flooded vestigial tree trunks, which is evidence of coseismic subsidence associated with the 1960 Valdivia earthquake as a source of environmental variability. The tidal flat with vestigial tree trunks registered the fastest and highest depth of inundation. In contrast, the tidal currents velocity and total suspended solids' concentrations were higher at the flat without trunks. Sudden rainfall events can significantly modify the characteristics of surface waters above sedimentary intertidal surfaces, where structures such as flooded trunks are present.

Sign in / Sign up

Export Citation Format

Share Document