Influence Of Rainfall Patterns Research Articles

The influence of rainfall patterns on factor of safety for clayey soil slopes

The persistent trend of rising temperatures and shifting weather patterns caused by climate change has prompted significant concern around the world. This research aims to evaluate the instability of slopes in Almaty, Kazakhstan, under various rainfall patterns, groundwater tables, and slope geometries by incorporating the principles of unsaturated soil mechanics. However, there have been a limited number of studies incorporating the principle of unsaturated soil mechanics with constant rainfall patterns in Central Asia, particularly in Kazakhstan, on the impact of rainfall-causing landslides. Hence, in this research, GeoStudio software (SEEP/W and SLOPE/W) was used to simulate the factor of safety (FoS) and pore water pressure for the investigated slopes under different rainfall patterns. Results from Hyprop and statistical method show that the saturated volumetric water content is 0.502, whereas the residual one is 0.147 and for the permeability function the conductivity coefficient started to sharply decrease at the suction value of 2 kPa when the air-entry value was 24 kPa. Findings from numerical analysis show the change in FoS for the slope of 10 m height and 27-degree slope angle was 6%, 7%, 7%, and 8% for cyclic, delayed, advanced, and normal distributions, respectively. For the slope with 20 m height and the same 27-degree angle, the change in FoS was 8%, 10%, 8%, and 11% for the cyclic, delayed, advanced, and normal distributions, respectively. These same patterns were shown in slopes with 35-degree and 45-degree angles, having the same 10 m and 20 m heights. Comparatively, this shows that slopes under cyclic rainfall patterns (240 mm of rain within 12 days) are less prone to failure compared to slopes under continuous, delayed, or regularly distributed rainfall patterns. Moreover, an increase in slope height and angle also affect the FoS negatively. It should be noted that the results obtained are only applicable to clayey-loam soil.

Analysis of Mini Polder Performance for Improved Water Management in the Dadahup Swampy Irrigation Area

The Indonesian government has chosen the Dadahup Swampy Irrigation Area as one of its Food Estate regions to address food security concerns. Following the rehabilitation of the irrigation network and the construction of gates from 2020 to 2022, block A5 is chosen as a pilot project using a mini polder as its water system management. In the right block A5, mini polders small-scale embankments are designed to regulate water flow and optimize land utilization. This research comprehensively evaluates the mini polder’s effectiveness in right block A5 in improving water control within the swampy landscape, considering the influence of rainfall patterns. Our study aims to comprehensively evaluate how mini polders effectively improve water control in the Dadahup Swamp Irrigation Area. To achieve this, we consider the influence of rainfall patterns, which play a significant role in the region’s hydrological dynamics. In addition to traditional data analysis, we integrate hydraulic simulations into our study using HEC-RAS software. These simulations allow us to model and visualize how mini polders interact with the complex water flow patterns in the Dadahup Swampy Irrigation Area. By combining empirical data with hydraulic simulations, we can better understand how mini-polders function in response to varying rainfall scenarios. Based on the simulation results, it was found that without the polder system, the water level would be on dry land during the dry season. The simulation provides direction or guidelines for polder operations to maintain the water level as long as possible during the dry season and prevent flooding during the rainy season. This research can provide valuable insights into sustainable agriculture practices in this unique and challenging environment.

Influence of rainfall pattern and infiltration capacity on the spatial and temporal inundation characteristics of urban waterlogging.

The rapid development of the city leads to the continuous updating of the land use allocation ratio, particularly during the flood season, which will exacerbate the significant changes in the spatial and temporal patterns of urban flooding, increasing the difficulty of urban flood forecasting and early warning. In this study, the spatial and temporal evolution of flooding in a high-density urban area was analyzed based on the Mike Flood model, and the influence mechanisms of different rainfall peak locations and infiltration rate scenarios on the spatial and temporal characteristics of urban waterlogging were explored. The results revealed that under the same return period, the larger the rainfall peak coefficient, the larger the peak value of inundation volume and inundation area. When the rainfall peak coefficient is small, the higher the return period is, and the larger the peak lag time of the inundation volume is, in which P = 50a, r = 0.2, the peak lag time of the inundation volume reached 32min and 45min for the inundation depths H > 0.03 m and H > 0.15 m, respectively. There are also significant differences in the peak lag time of waterlogging inundation volume for different inundation depths. The greater the inundation depth, the longer the peak lag time of the inundation volume, and the higher the return period, the more significant the effect of lag time prolongation. It is worth noting that the increase in infiltration rate may lead to an advance in the peak time of inundation volume and inundation area, and the peak time of the inundation area is overall more obvious than that of inundation volume. The effect of infiltration rate on the peak time of inundation volume for larger inundation depths was relatively large; the peak times of inundation volume and inundation area were advanced by 4-6 min and 4-8 min for H > 0.03 m and H > 0.15 m, respectively, after the increase in infiltration rate, and the higher the rainfall return period, the longer the advance time. The spatial and temporal characteristics of waterlogging under different peak rainfall locations and infiltration capacities obtained in this study can help provide a new perspective for temporal forecasting and warning of urban waterlogging.

Influence of Rainfall Pattern on Wetness Index for Infinite Slope Stability Analysis

Landslides are one of the riskiest disasters combining excessive rainfall and unstable slope that a wetness index can quantify. The wetness index generated by water infiltration considering the rainfall pattern such as cumulated rainfall, rainfall duration and rainfall intensity should be estimated for the slope stability analysis. Even though the infiltration capacity of soils has been largely focused to evaluate the slope stability, the temporal patterns of rainfall have commonly been ignored or assumed as a steady state for the prediction of the slope failure in the previous studies. Thus, this study focuses more on evaluating the influence of various rainfall patterns on the slope stability, and compares it with an actual landslide incident that occurred in 2011, in Korea. The factor of safety (FS) considering the time-dependent wetness index variation is used to determine the slope stability. For the various rainfall designs, the uniform rainfall distribution, Yen and Chow, Mononobe, alternating block and second quartile Huff models are adopted. Thereafter, the FS variations from five models are compared with an actual landslide incident in Seoul, Korea. Among the rainfall designs, the models that consider the abrupt rainfall intensity capture the landslide time with an FS < 1. Therefore, the appropriate adoption of a rainfall distribution model should be highlighted for landslide prediction.

Influence of Rainfall Pattern and Traffic Variability on the Occurrence of PAHs in Road Surface Runoff

Influence of Rainfall Pattern and Traffic Variability on the Occurrence of PAHs in Road Surface Runoff

Influence of Rainfall Pattern on Effect of Nitrogen and Potassium Topdressing in Combination with Local Application of Nitrogen and Potassium at the Timing of Sowing on the Growth and Yield of Direct-seeded Onions (<i>Allium cepa</i> L.)

タマネギの直播栽培は移植栽培に比べて2週間程度生育期間が長いために気象条件の影響を受け易い．そこで，北海道十勝地域における窒素，カリウムの直下施肥と窒素とカリウムの分施を組み合わせについて実験年度の違いによる直播タマネギの生育と収量に及ぼす影響を調べた．また，上記の施肥方法の違いによる生育および収量について，試験年度の違いに及ぼす降雨による土壌水分の違いの影響を調査した．実験年度によって結果が異なり，生育に及ぼす窒素とカリウムの分施効果が降水量の影響を受けたと考えられた．その結果，施肥方法の違いがりん茎につながらなかった要因は，各実験年の養分吸収量の違いにより影響されたことと推測した．収穫時のりん茎重に影響を及ぼす肥大始期の葉面積を確保するためには6月下旬までの肥効が重要であり，肥効はこの時期の降雨の影響を強く受けることが示唆された．

Rainfall patterns associated with runoff and erosion levels in West-Siberian Chernozems

The aim of the study was to identify 1) the main regularities of surface runoff formation due to downpours and 2) the extent of erosion process on arable chernozems in areas with dissected relief and sharply continental climate. The influence of rainfall patterns and soil physical factors on soil erosion was studied in three large geomorphological regions in the South-East of West Siberia. Field observations were carried out during 1968–1979 in the Kuznetsk Depression and in 1984–1986 in the Near-Ob areas, and from 1995 until present in the Near-Salair area. The data of meteorological stations were analyzed for rainfall patterns in the same years, including inter-year variability and downpour recordings. Summer precipitation and its intensity were measured by using hydrograph unit. Water infiltration in the field was studied by the method of small flooded areas (Nesterov’s method), when square or round frames with an area of 2500 (external) and 625 cm2 (internal) were installed on the soil surface. To simplify and automate water supply, the PVN-00 device was used, consisting of two hermetically sealed tanks, two cylindrical frames of different diameters and a tripod. The influence of rainfall patterns and soil physical factors on the processes of soil erosion was studied. As regards climatic factors the data of meteorological stations were analyzed for historical rainfall patterns, including interannual variability and downpour recordings. Experimental data of water infiltration, runoff and soil loss were discussed for the main soils units: Greyzemic Phaeozems (Siltic), Luvic Chernozems (Siltic) and Haplic Chernozems (Siltic) with variable content of soil organic matter and erosion levels. The studied regions were characterized by the prevalence of precipitation during the warm growing season and by sporadic or cyclical precipitation patterns. Heavy rains were found to cause significant damage to agricultural land only locally, during early spring, when the soil is not protected by vegetation. The greatest erosion hazard is represented by meltwater, not only by its total amount, but also by the snow thawing rate. The significant decrease in the infiltration rates with extensive farming is the main factor of degradation of the most fertile soils in West Siberia. Soil vulnerability to erosion in the studied area was shown to decrease in the range: Kuznetsk Depression > Near-Salair > Near-Ob (no storm damage).

Effect of rainfall variability on the production of Vigna unguiculata (L.) Walp. in the semi-arid region of Paraíba

Agricultural production in semi-arid areas of the globe is dependent on species adapted to conditions of low availability of resources, such as water. Cowpea (Vigna unguiculata L. Walp.) is a vegetable widely grown in regions with water restrictions, however, even with its good adaptability, it is vulnerable to the effects of prolonged droughts. In this sense, this research aimed to analyze the influence of rainfall patterns on the production dynamics of cowpea during the period of fifteen years (2002-2016) in the municipality of Conceição, Paraíba, Brazil. A correlation matrix was used to analyze the influence of precipitation on the production variables of the cowpea crop, as well as the relationship between these variables. Subsequently, the Principal Component Analysis (PCA) was carried out. The results showed a strong reduction in the production variables of cowpea from the year 2012, which is due to the reduction of rainfall in this period and was proven through the correction matrix, which showed a positive correlation of rainfall mainly with the planted and harvested area. The PCA recorded 91.02% of explanation in the first two axes, and demonstrated that for production and productivity, other factors in addition to good rainfall levels are necessary to increase the productive results of cowpea in the municipality.

Laboratory Studies on the Influence of Rainfall Pattern on Rill Erosion and Its Runoff and Sediment Characteristics

AbstractRill is a major type of erosion on upland slopes. Continuous rainfall is commonly used in laboratory studies on rill erosion despite the fact the rainfall was often discontinuous in the field; this is particularly true in the Chinese Loess Plateau. This study compares rill erosion under continuous and intermittent rainfalls by using laboratory experiments. The experiments include two rainfall‐intensity treatments (90 and 120 mm h−1) and two rainfall‐pattern treatments (continuous and intermittent). The results indicate that rill formation had a significant effect on runoff and sediment concentration. For continuous and intermittent rainfall at the rainfall intensity of 90 mm h−1, the mean sediment concentrations were 1·91 and 1·73 times after rill initiation than those before rill initiation, respectively, and the rill erosion accounted for 75·5% and 77·7% of runoff duration, respectively. For continuous and intermittent rainfall at the rainfall intensity of 120 mm h−1, the mean sediment concentrations after rill initiation were 1·38 and 1·32 times that those before rill initiation, respectively, and the rill erosion represented 88·7% and 78·8% of the total runoff duration, respectively. We observed sediment sorting under all treatments; however, the low rainfall intensity boosted but the high rainfall intensity lowered the clay fraction; in contrast, the sorting remained roughly the same between the rainfall‐pattern treatments. The runoff velocity also affected the sediment sorting. Our empirical results indicated the important significance of the rainfall intermittence in predicting rill erosion. Copyright © 2017 John Wiley & Sons, Ltd.

Proximal sensing for monitoring the productivity of a permanent Mediterranean pasture: influence of rainfall patterns

The main objective of this work was to evaluate technologies that have potential for monitoring aspects related to spatial and temporal variability of soil nutrients and pasture yield and for support to decision making by the farmers. Three types of sensors were evaluated: an electromagnetic induction sensor, an active optical sensor and a capacitance probe. The results are relevant for the selection of the adequate sensing system for each particular application and to open new perspectives for other works that would allow the testing, calibration and validation of the sensors in a wider range of pasture production conditions and rainfall patterns, characteristic of the Mediterranean region.

Influence of Rainfall Patterns on the Instability of Slopes

The assessment of rainstorm-induced shallow landslides is still a research topic of wide concern for scientists and engineers. This paper examined the effect of rainfall intensity distribution on shallow landslides. Four synthetic rainfall distributions comprising uniformed, delayed, centralized, and advanced, were selected to examine the effect of rainstorm patterns on slope failure. The infiltration was modeled using Green-Ampt equation, while an infinite slope was selected to model the shallow landslide. Monte Carlo Simulation was applied to analyze the failure probability of the slopes. Two landslide cases were selected to examine the proposed model. The results indicated that among the four representative rainstorm patterns, the advanced rainfall pattern caused worst slope stability. The advanced rainfall pattern resulted in the shortest rainfall duration threshold for landslide occurrence, followed by the central, uniform, and then delayed rainfall pattern. The probabilistic analysis method was suitable to estimate the time of failure for the evaluated landslide cases.

Influence of Rainfall Pattern in the Seasonal Variation of Fish Abundance in a Tropical Estuary with Restricted Marine Communication

Pueblo Viejo Lagoon is an estuary with restricted communication with the sea, so the freshwater influence tends to be more important. Therefore, the study focused on testing the hypothesis that the seasonal changes in species abundance would be mainly related to the local rainfall pattern. Monthly samplings were carried out over a one-year, using a seine net. A total of 9108 individuals were caught, corresponding to 66 species of fish, most of them with marine origin. Canonical correspondence analysis revealed that the rainfall-salinity gradient was revealed to be the most important driving force in the seasonal variation of fish composition. In this way, it was observed that seasonal fluctuations in total fish number were linked to preceding fluctuations (one month) in local rainfall. Similar pattern was exhibited by the abundance of Anchoa mitchilli (the most abundant species), Oreochromis mossambicus and Ariopsis felis, and this delayed effect was significant (cross-correlation analyses). In addition, the rainfall showed a direct influence (significant positive correlations) on abundance of D. auratus and M. martinica. The association between fish number and the rainfall regime seems to be related to lagoon productivity and the trophic responses of these species. By contrast, Brevoortia gunteri and Menidia beryllina showed an inverse correlation with rainfall. Other environmental variables (also influenced by rainfall regime) showed a significant relationship with A. hepsetus (salinity), B. chrysoura (depth) and M. curema (turbidity). Thus, at least 12 species showed some relationship with local rainfall, which accounted for 81.27% of the total number of fish collected. Although it is difficult to separate the relative importance of physiological tolerances and biological functions such as trophic responses, the results suggest that rainfall is a primary factor governing seasonal variation in fish species abundance of Pueblo Viejo lagoon.

인공강우와 콩재배 포장 라이시메타를 이용한 endosulfan의 유출량 평가

강우에 의한 경사지 토양으로부터의 농약 유출양상을 파악하고 그에 대한 농약의 특성, 환경적 요인 및 영농방법 등의 영향 정도를 평가하기 위하여 토양흡착실험과 인공강우유출 실험 및 콩 재배 lysimeter 포장에서 유출실험을 수행하였다. Endosulfan의 흡착법에 의한 흡착계수 (K)는 <TEX>$77{\sim}131$</TEX>이었으며, 탈착법에 의한K값이 흡착법으로 구한 값보다 높았다. 영국 SSLRC의 이동성 분류기준에 의하면 endosulfan은 Koc 4,000을 초과하여 non-mobile 등급에 속하였다. 인공강우 처리구의 유출수 및 유실토양에 의한 endosulfan의 유실율은 <TEX>$3.4{\sim}5.6%$</TEX> 및 <TEX>$4.4{\sim}15.6%$</TEX>이었다. 인공강우실험 후 토심별 분포를 살펴 본 결과 대부분의 endosulfan 잔류분은 토심 5 cm 이내에 잔류하였다. 경사도 30%의 경우가 10%에 비하여 각 농약의 유실량이 <TEX>$0.6{\sim}0.9$</TEX>배 많았는데 유출수에 의한 농약의 유실량 차이는 유출수 중 농도 차이로 볼 수 있으며, 유실토양에 의한 농약 유실량 차이는 토양 유실량과 관계되는 것으로 생각되었다. Lysimeter 포장유출실험 결과 경사도 및 경사장별 endo-sulfan 유실량은 살포량 대비 <TEX>$5{\sim}35%$</TEX> 수준이었다. 콩재배구의 유실율은 나지구의 유실율에 비하여 평균 66% 수준이었다. 경사조건의 영향을 살펴보면 유출수의 경우에는 그 차이가 크지 않았으나 유실토양에 의한 유실율은 경사도와 경사장 증가에 따라 <TEX>$4{\sim}12$</TEX>배까지 증가하는 것으로 나타났다. 한편 유출수 중 농약성분의 최고농도는 콩재배구 및 나지구 각각 <TEX>$8{\sim}10{\mu}gL^{-1}$</TEX> 및 <TEX>$7{\sim}9{\mu}gL^{-1}$</TEX> 수준으로 작물 재배 여부에 따른 유출수 중 농도의 차이는 크지 않은 것으로 나타났다. Three different experiments were carried out to investigate the runoff and erosion losses of endosulfan from sloped-field by rainfall. The mobility of endosulfan and which phase it was transported by were examined in adsorption study, the influence of rainfall pattern and slope degree on the pesticide loss were evaluated in simulated rainfall study, and the pesticide losses from soybean-grown field comparing with bare soil were measured in field lysimeter study. Adsorption parameter (K) of endosulfan ranged from 77 to 131 by adsorption method and K values by the desorption method were higher than those by the adsorption method. By the SSLRC's classification for pesticide mobility endosulfan was classified as non-mobile class (<TEX>$K_{oc}>4,000$</TEX>). Runoff and erosion loss of endosulfan by three rainfall scenarios ranged from 3.4 to 5.6%and from 4.4 to 15.6%of the amount treated. Endosulfan residues were mainly remained at the top 5 cm of soil depth after the simulated rainfall study. Pesticide loss in case of 30%-slope degree ranged from 0.6 to 0.9 times higher than those in case of 10%-slope degree. The difference of pesticide runoff loss was related with its concentration in runoff water and the difference of pesticide erosion loss would related closely with the quantity of soil eroded. Endosulfan losses from a series of lysimeter plots in sloped land by rainfall ranged from 5 to 35% of the amount treated. The erosion rate of endosulfan from soybean-plots was 66% of that from bare soil plots. The effect of slope conditions was not great for runoff loss, but was great for erosion loss as increasing to maximum <TEX>$4{\sim}12$</TEX> times with slope degree and slope length. The peak runoff concentration of endosulfan in soybean-plots and bare soil plots ranged from 8 to 10 and from 7 to <TEX>$9{\mu}gL^{-1}$</TEX> on nine plots with different slope degree and slope length. Therefore the difference of the peak runoff concentrations between bare soil plots and soybean-plots were not great.

인공강우에 의한 alachlor, ethalfluralin, ethoprophos 및 pendimethalin의 토양표면 유출

Two different experiments, adsorption/desorption and runoff by rainfall simulation of four pesticides, such as alachlor, ethalfluralin, ethoprophos and pendimethalin were undertaken their runoff and erosion losses from sloped land and to assess the influence of their properties and environmental factors on them. The mobility of four pesticides and which phase they were transported by were examined in adsorption study, and the influence of rainfall pattern and sloping degree on the pesticide losses were evaluated in simulated rainfall study. Freundlich adsorption parameters (K) by the adsorption and desorption methods were 1.2 and 2.2 for ethoprophos, 1.5 and 2.6 for alachlor, respectively. And adsorption distribution coefficients (Kd) by the adsorption and desorption methods were 56 and 94 for ethalfluralin, and 104 and 189 for pendimethalin, respectively. K or Kd values of pesticides by the desorption method which were desorbed from the soil after thoroughly mixing, were higher than these ones by the adsorption method which pesticides dissolved in water were adsorbed to the soil. Another parameter (1/n), representing the linearity of adsorption, in Freundlich equation for the pesticides tested ranged from 0.96 to 1.02 by the desorption method and from 0.87 to 1.02 by the adsorption method. Therefore, the desorption method was more independent from pesticide concentration in soil solution than the adsorption method. By Soil Survey and Land Research Center (SSLRC)'s classification for pesticide mobility, alachlor and ethoprophos were classified into moderately mobile $(75{\leq}Koc 4000). Runoff and erosion loss of pesticides by three rainfall scenarios were from 1.0 to 6.4% and from 0.3 to 1.2% for alachlor, from 1.0 to 2.5% and from 1.7 to 10.1% for ethalfluralin, from 1.3 to 2.9% and from 3.9 to 10.8% for pendimethalin, and from 0.6 to 2.7% and from 0.1 % 0.3% for ethoprophos, respectively. Distribution of pesticides in soil profile were investigated after the simulated rainfall study. Alachlor and ethoprophos were leached to from 10 to 15 cm of soil layer, but ethalfluralin and pendimethalin were mostly remained at the top 5 cm of soil profile. The losses of the pesticides at 30% of sloping degree were from 0.2 to 1.9 times higher than those at 10%. The difference of their runoff loss was related with their concentration in runoff water while the difference of their erosion loss must be closely related with the quantity of soil eroded.

A surface regression approach for estimation of genetic and environmental trends under widely varying meteorological conditions between years

Under tropical conditions meteorological variations may be a major source of nuisance in the estimation of genetic and environmental progress achieved. In this paper an approach is presented to incorporate polynomial functions of rainfall in the statistical model for estimating genetic and environmental trends. The idea behind is to separate the year‐season effect into causal components, i.e. influence of rainfall pattern, temporary management effect and environmental trend. Records on milk yield from a large commercial Jersey herd in Kenya covering a period of 14 years (1980–93) were used to illustrate this approach. The farm is located in upper midland agro‐ecological zone of Rift Valley. It became evident that the rainfall pattern beginning one year prior to calving influenced the later milk performance in a complex way. The proposed model proved to be successful in separating the year‐season effect into its causal components and thus gave better estimates of environmental and genetic trends.

Hydrologic processes controlling sulfate mobility in a small forested watershed

Hydrologic controls on sulfate mobility were investigated in a forested catchment in the Georgia Piedmont using a watershed mass balance approach. Variations in annual sulfate export were governed primarily by differences in runoff rather than by differences in sulfate deposition or in total annual precipitation. However, 2 years with similar total runoff had substantially different sulfate export. A residual analysis indicated that a shift in the concentration‐discharge relationship accounted for 72% of the difference in sulfate export and that a change in the pattern of discharge accounted for the remainder of the difference. Stream water sulfate concentrations reflected past hydrologic conditions. Concentrations at the same discharge were higher following an extended dry period than following average periods. The elevation in stream water sulfate concentrations following dry periods persisted for several months. The influence of rainfall patterns on sulfate export underscores the need for long‐term records to adequately characterize the acidification status of the watershed and to understand trends in water quality.

Distribution of metals in the Linggi River Basin, Malaysia, with reference to pollution

Pollution inputs into the Linggi River Basin comprise domestic sewage, agroindustrial effluent (especially from rubber factories and palm-oil mills), and effluent from animal-husbandry activities. Total metals were analysed at eight sampling stations located at three highly polluted sub-basins: Linggi, Simin and Kundor. Dissolved metals were analysed occasionally at 21 major tributaries. The following concentrations were found (mg L-1; d.l., detection limit): Na, 0.93-117.73; K, 0.88-77.03; Ca, 1.89-24.00; Mg, 0.30-14.78; Fe, 0.47-12.2; Zn, 0.06-5.12; Cu, &lt; d.l. -2.88; Mn, &lt; d.l.-0.18. Pb, Ni and Cr were not detectable in their dissolved or total forms. Organic sewage inputs greatly increased the concentration of metal ions in reaches just downstream of discharge points. Ion concentrations generally decreased, but not substantially so, in the recovery reaches. Various pollutants contributed differentially to the concentrations of specific metal ions; rubber-factory effluent contributed slightly lower amounts of these ions than did industrial, urban, or palm-oil-mill effluents. No seasonal changes can be readily detected because of the influence of rainfall patterns, variable effluent discharges, and a complex combination of physical, chemical and biological processes occurring in the river.