Rainwater Infiltration Research Articles

Study on Thermal Performance Measurement and Construction of Passive Exterior Wall with Low Energy: Teaching and Laboratory Building of Shandong Jianzhu University

It can provide theoretical support for the optimal design of low-energy walls by measuring the actual thermal conditions inside the walls of passive low-energy buildings and studying the rationality of the wall structure design. Taking the teaching and laboratory building of Shandong Jianzhu University as an example, this paper explores the method of using temperature and humidity sensor to measure the air temperature and humidity inside the wall to represent the solid temperature and humidity of the wall. Based on the measured data and calculation results, the rationality of the structure of the test external wall is analyzed from four aspects: the performance of insulation, the moisture drain performance of wall, the ability of preventing the penetration of the hot and humid air of the inner wall, and the waterproof performance of the outer wall. Results show that the external wall structure of polystyrene board (200 mm thick) for external insulation and thin plastering has good practical operation effect in three aspects of thermal insulation, internal moisture discharge, and external wall waterproof, which basically meets the design requirements of external wall of passive house in Germany. In terms of moisture protection of the inner wall, the inner wall of cement mortar (15 mm thick) may not be able to effectively prevent the infiltration of indoor hot and humid air. Thus, the insulation layer should be added into the external wall. In addition, the moisture inside the wall is obviously affected by the season. The drain performance of moisture inside the wall mainly occurs in the sweltering heat, and the drain direction is from the indoor side to the outdoor side. In the external insulation structure, there are two layers of graphite polystyrene plate (100 mm thick), and the insulation effect of polystyrene plate near the outdoor side is better than that near the indoor side. The combination of anticrack mortar (5 mm thick) and paint cannot completely prevent the infiltration of rainwater, but the infiltration of rainwater in the wall will be quickly discharged in a short time.

Physical Model Study of an Intermittent Rainfall-Induced Gently Dipping Accumulation Landslide

Many slope failures have been observed in deep-cutting gorges in Southwest China due to rainfall events. This study conducted model-based tests of the failure of a gently dipping accumulation slope caused by intermittent rainfall. The physical model was established by configuring soil samples based on similarity theory and direct shear test data. Intermittent rainfall was simulated by supplying surface runoff and bottom pressure water of the slope. The deformation, earth pressure, and pore pressure were observed during the test using a series of transducers. The results of this research showed that slope failure was first initiated at the toe of the slope. Staged sliding failure then occurred, which spread the unstable zone to the trailing edge of the slope. As infiltration of rainwater continued, the pore pressure increased and the matric suction and effective stress at the bedrock surface decreased, causing failure of the slope.

ENVIRONMENTAL IMPACT OF CHAKRIYA VIKAS PRANALI ON SOIL AND GROUNDWATER: A CASE STUDY OF JORKAT VILLAGE OF PALAMU DISTRICT, JHARKHAND, INDIA

The Chakriya Vikas Pranali changes degraded land to upgraded land which increases groundwater level, soil composition resulting change in structure, texture and water holding capacity of the soil. Plantation in the Treated zone increases rainwater in the area and porosity and permeability of the soil increases thus increasing percolation of rainwater. KEY WORDS: Chakriya Vikas Pranali, groundwater, soil composition, treated zone, percolation, rainwater.

Analysis of Rainfall Erosion and Protective Measures for the Aeolian Sand Subgrade Slope of the Wuma Expressway

It is difficult to build roads in the desert areas with wind-blown sands because the prevailing harsh environment and the characteristics of the aeolian sands inhibit strategies and measures for road damage prevention and control that are typically effective in other settings. Typically, the rainfall period in aeolian sand areas worldwide is concentrated and the rainfall volume is relatively large, which combined with small and unstable nature and the aeolian sand particles means roads built in these areas can be easily washed away and are vulnerable to water damage. Given geological conditions, topographic features and hydrometeorological conditions differ depending on the region, basic research into water damage in highway roadbed slopes in aeolian sand areas is necessary to formulate treatment measures that are versatile and applicable in different regions. Towards that end, this study strengthens the evaluation of roadbed and pavement drainage and protective measures given aeolian sand erosion caused by rainwater infiltration in certain longitudinal length sections of the Expressway K165 + 250 mileage pile section, and includes verification of the design scheme. The effects of rainwater drainage, storage, and subgrade reinforcement on the seepage and stability of drainage in a long longitudinal slope in the desert hinterland were quantitatively analyzed using numerical analysis. Additionally taking into account the regional climate environment characteristics that locally prevail, the necessity and applicability of geotechnical reinforcement in practical engineering applications is demonstrated. The research found the stability of the subgrade slope given potential for rainfall erosion due to concentrated-rainfall periods in an aeolian sand region is promoted through measures including slope drainage on the highway combined with side ditch drainage, strengthening of the box culvert under embankment ditches, and local protection by laying geogrid in the embankment to produce a significant lateral diffusion effect.

森林のもつ雨水浸透貯留機能について

森林のもつ雨水浸透貯留機能について

An Analysis of Critical Slopes Stability in Bendosari Village, Pujon, Malang Due to The Effect of Rainwater Infiltration

A disaster is an incident which threatens and disrupts life. This research was purposed to determine the critical slope stability in Bendosari Village, Pujon due to rainwater infiltration. This research was conducted through ground laboratory test to investigate the type and characteristic of the soil, which then followed by testing of the geo-electric and topography to investigate the existing condition and the ground water level on the critical slopes and analyzed safety factor (SF) using SLOPE/ W for slope with rainwater infiltration effect. The analysis results proved that rainwater infiltration in both conditions could reduce the SF (Safety Factor) value. This is because the water content in the soil increased the pore water pressure. In addition, high water content in the soil reduced the soil shear strength

Influence of Rainfall Infiltration on Stability of Granite Residual Soil High Slope

The seepage evolution characteristics and stability change rule of granite residual soil inside the high cutting slope under the action of rainfall infiltration were studied. Based on the saturated-unsaturated seepage theory, the numerical simulation of the rainwater infiltration path inside the granite residual soil slope was carried out under the condition of rainwater infiltration. The evolution characteristics of the seepage field of the granite residual soil cutting high slope under the condition of rainfall infiltration were revealed, and the influence of the rainwater infiltration on the stability of the granite residual soil slope was mainly studied. The research results show that with the accumulation of rainfall infiltration, the pore water pressure of the granite residual soil slope increases continuously, and the pore water pressure of the soil below the platform increases the fastest. With the increase in elevation, the water content of the slope presents a wave crest distribution. In the early stage of rainfall, the seepage velocity vector distribution on the slope surface is relatively uniform. In the middle stage of rainfall, the seepage velocity vector is the most dense at the platform, and the rainwater migration rate is accelerated. In the later stage of rainfall, the infiltrated rainwater at the slope angle of the first-level slope spreads to the surrounding area. With the continuous rainfall, the slope stability safety factor gradually decreased unevenly, and after the rainfall stopped, it gradually increased with the rainwater infiltration.

Characterization of the soil and rock hosting an aquifer with possible uses for drinking water and irrigation in SE Panama City using Geotechnical, Geophysical and Geochemical parameters

The supply of water to populations is a basic need that has been threatened more frequently in recent years due to climate change, which renders seeking other sources of water essential. The hydrochemistry of the groundwater of the aquifer located in the UTP Tocumen was characterized by previous research to determine its possible use as a source of drinking water and irrigation water. The objective of this study is to characterize the soil and rock hosting the aquifer to acquire more information about them with a view to possibly exploit an alternative source of drinking water. To this end, a 10-m-depth survey was conducted to obtain soil and rock samples from the area, and to characterize geotechnical and geochemical parameters. 2D electrical resistivity tomography was used to create a lithological model of the aquifer and to correlate the data. Soil is residual of the technosol type, considered permeable with a transmissivity level that favors rainwater infiltration, followed by the soil–rock interface, where rock is weathered. It´s followed by a sedimentary rock corresponding to marly siltstones with a certain degree of tectonic fractures that allow water infiltration and its accumulation in the rocks, constituting the aquifer. The 2D electrical resistivity suggests two water accumulations: a superficial and a deep one. There was a good correlation between the aquifer water’s chemistry and the rock geochemistry.

Role of the geologic-geomorphic setting of the Río de la Plata estuary coastal landscape in controlling freshwater lenses shape and distribution

Sea level fluctuations during the Holocene led to the deposition of different sedimentary facies in the Argentinean littoral of the Río de la Plata estuary and the adjacent sea area. This work aims to analyze the role of the geologic – geomorphic setting related to the Holocene evolution of the coastal landscape of the Río de la Plata estuary in terms of its control over the shape and distribution of freshwater lenses for water supply. For this purpose, satellite image analysis, field surveys, Vertical Electrical Soundings (VES), and sediment tests from boreholes were carried out. In addition, water samples were taken for electrical conductivity (EC) measurement, and major ions and stable isotopes of the water molecule determination. The results show that the geological and geomorphological evolution of the Río de la Plata estuary gave rise to positive landforms composed of highly permeable sediments that favor rainwater infiltration, which is stored in the shape of lenses. EC measurements in groundwater below these landforms recorded low values indicative of freshwater with isotopic content similar to that of local – global rainfall. Furthermore, the VES study allowed the definition of the freshwater – saline water interface. The outcomes of this study show that a detailed and exhaustive analysis of the geological – geomorphic setting resulting from the Holocene evolution of coastal zones constitutes, along with hydrochemistry and geophysics, appropriate tools for the exploration of freshwater lenses in coastal areas.

Harvested Rainwater Quality of Dhaka and Its Importance as the Alternative to Surface and Groundwater

Dhaka, like many other megacities in southern Asia, has been struggling with urban flooding and droughts. The main reason behind the problem is thought to be the propagation of the city's built-up area and a significant decrease in rainwater infiltration in the capital. On the contrary, the continuous safe water supply in Dhaka is becoming an impossible task for the authority as the ground and surface water is being depleted over the years. In this regard, proper rainwater management, even at the individual plot level, has the potential to bring up a significant difference in the present crisis. In this report, the total physiochemical quality assessment of the harvested rainwater from Dhaka city has been presented and compared with that of the World Health Organization (WHO) standard. For the first time, this study reveals the applicability of this harvested rainwater to be used in several aspects including drinking, cooking, agricultural, industrial, and household purposes.

Numerical investigation of the influence of banded sand ditches on water infiltration in fine-textured soil.

Enhancing rainwater infiltration is important to reduce the risk of urban waterlogging and improve the utilization rate of urban rainwater resources. Using the HYDRUS model, a mathematical model of soil water movement under a banded sand ditch pattern (the vertical excavation of a deep trench with heavy soil and filled with light soil) was created. Forty-six scenarios were designed to examine effects of sand ditch soil saturated hydraulic conductivity (Kss), original homogenous fine-textured soil saturated hydraulic conductivity (Kso), sand ditch width (W), spacing (S), and depth (D) on the soil infiltration rate (i). Results indicate that banded sand ditches cause increased permeation and have a significant turning point 't0' in the curve of 'i' for 't.' Taking 't0' as the boundary, 'i' can be divided into two stages (t ≤ t0 and t > t0), 'i' and 't,' for each stage according to the power function relationship; there is little change in power function indices, which can be fixed at 0.34 and 0.63, respectively. In addition, the coefficient has a linear relationship with Kss, Kso, W, S, and D. Thus, an estimation model of the soil infiltration rate under a banded sand ditch pattern was proposed and verified for reliability.

Function of a Deep-Buried Isolated Trench and Its Effect on Cracking Failure Characteristics of a Slope under Artificial Rainfall

When tests are conducted on the field slope under artificial rainfall, because artificial rainfall is often limited to implementation in the mode of local rainfall, there is a boundary constraint effect between the rainfall area and the non-rainfall area, which is manifested in the lateral infiltration of rainwater and the slope deformation retardation of non-rainfall area to the rainfall area. Firstly, a deep-buried isolated trench was proposed to solve these boundary constraints. Then, field cracking tests and the corresponding numerical simulation were conducted under rainfall. In the end, the response of water content and the cracking failure characteristics of the slope were analyzed during rainfall, and the effect of a deep-buried isolated trench on the cracking characteristics of the slope was evaluated. The results indicate that the proposed deep-buried isolated trench measure can effectively eliminate the deformation retardation resulting from the adjacent non-rainfall area so a through-crack parallel to the slope shoulder that extended on both sides of the boundary of the rainfall slope was observed at the slope crest and a cracking failure in the shape of the overall downward cutting was realized. As the crack occurred, the rainwater infiltration further aggravated expansion of depthwise cracks, and a local sliding zone was formed in the upper part of the slope. The deep-buried isolated trench solves the boundary constraints, such as lateral infiltration of rainwater and deformation retardation, and can provide an effective technical measure for the field slope test under artificial rainfall.

STUDY ON THE ENVIRONMENTAL ASPECTS OF PIT CLOSURE GUIDELINES FOR OIL AND GAS PRODUCTION ACTIVITIES

Exploration, development, and production activities associated with oil and gas production projects can have a variety of impacts on the environment. A variety of wastes are produced by such activities. Apart from the wastewater that is in the form of produced water, many kinds of solid wastes are produced during exploration and production of oil and gas. These solid wastes, among others, are drilling mud and cuttings, and tank bottom oily sludge. These solid wastes are dumped temporarily in a certain place called a pit before they can be treated further. In order to minimize and possibly eliminate the environmental impacts of those solid wastes, pit construction has to be developed in such a way that release of pit contents to the environment could be prevented. In addition, pollutant loading of ground water from waste leaks, releases of hydrocarbons and hydrogen sulphide to the atmosphere are some of the factors that have also to be considered. As dumping such solid wastes in a pit is a temporary storage, pit closure management has also to be developed. Explicitly, governmental regulation concerning with environmental aspects of pit closure has not been established yet. Nevertheless, environmental management approach of pit construction and closure could be established by referring to the available regulation, namely Governmental Regulation PP. 18/1999 juncto PP. 85/1999 - hazardous waste regulation, and the related Ministerial Decree, such as Bapedal Decree No. Kep.-04/BAPEDAL/09/19995 decsribing methods of landfilling or land disposal for hazardous wastes. This approach is based on the reason that such solid wastes are also categorized as hazardous wastes. In regard to pit construction, study on pit location should include the hydrogeology pattern of the site. Furthermore, pit wall materials are parameters that also have to be considered in minimizing impacts to the surrounding. Upon closing the pit, a pit closure plans that call for the dewatering of mud and reserve pit contents before burial have to be developed to reduce the chance of the downward transport of contaminants to shallow aquifers. The grading of soils covering the pits may reduce the chances of infiltration of rainwater, which may migrate to ground water. Other consideration, for example revegetation, has also to be included. All of the above factors should be considered in pit closure and assessment guideline. In addition to the available national references, other worldwide references such as those of US-EPA guidelines deserve to be considered in studying pit management. The author has conducted a short study concerning pit closure management that has been implemented in oil and gas producing companies. Goals of the study are to review the manual guideline or standard operating procedure (SOP) of pit closure applied to the fields. The followings are report concerning with the implementation of the study.

Estimation of replenishable groundwater resources and their utilization status in hard rock terrain

For an efficient management and development of groundwater resources, it is imperative to have a reliable database on groundwater resources. In this regard, present study was conducted during 2015–18 in Mahatma Gandhi Chitrakoot Vishwavidyalaya, Chitrakoot, Satna, Madhya Pradesh, India. Dynamic groundwater resources of study area have been estimated by using the guidelines of the groundwater resources estimation committee (GEC-1997), Ministry of Water Resources, Government of India. In this study, rainwater infiltration factor (RIF) techniques and different conventional norms were used for groundwater recharge estimation. The assessments of groundwater units were categorized based on stage of groundwater development for the year 2016. The annual groundwater draft for all uses such as domestic and irrigation was 5931.54 ha m. The annual groundwater recharge in the study area was 8666.81 ha m and net annual groundwater availability was 8318.85 ha m. The groundwater utilization and stage of groundwater development had also been determined and the overall stage of groundwater development of Babina block was found to be 71.30%. There was no significant rise or fall of water levels during both the pre-monsoon and post-monsoon intervals in the study area. Considering the stage of groundwater development, it has been categorized that Babina block of Jhansi district, a part of Bundelkhand region falls under ‘SAFE’ category of groundwater development with excellent potential for the future groundwater development.

Temporal and spatial characterization of sediment transport through a karst aquifer by means of time series analysis

The process of sediment transport through a karst aquifer is investigated by means of time series analysis. The correlation and spectral analyses are used for determination of the temporal characteristics of this process, such as timing, synchronization with discharge from spring, and time delay between arrivals of sediment and infiltrated rainwater to spring. The partial correlation analysis is used for the spatial characterization. The study area is the catchment of Jadro Spring in Croatia. The analyzed hourly time series are discharge, water temperature, electrical conductivity, and nephelometric turbidity recorded at the source of this spring, as well as the rainfall collected at three locations in the catchment of spring. They cover the period of four years, from 2017 to 2020. The main aims of this research are (1) presentation of the methods of time series analysis that can be used for the investigation of sediment transport through karst aquifer, (2) analysis of the applicability of partial cross-correlation functions for the spatial characterization of sediment transport process, and (3) extension of the existing knowledge about the sediment in water from karst springs with a special reference to the Jadro Spring. The obtained results show that the partial cross-correlation function can be very useful in the investigation of mass transport through the karst aquifer. They enable identification of the specific contribution of each rain-gauge location to the quantity and quality of spring water. Specifically, the origin of sediment in water from Jadro Spring is determined in this study, as well as the origin of quick-flow and baseflow component in discharge from this spring, including the timing of fresh rainwater arrival, rainwater withdrawal, and emptying of previously accumulated water in vadose and phreatic zone. The sediment transport through the karst aquifer of Jadro Spring is initiated after heavy rainfall in the central and eastern part of the catchment. The origin of sediment in spring water is dominantly the remobilized autochthonous sediment from aquifer, and possible limited contribution of allochthonous sediment from the part of catchment located in hinterland of spring.

Urban households' willingness to pay for improvements in rainwater harvesting and rainwater infiltration system: Case study in Japan

AbstractThere is an urgent need to develop an urban rainwater drainage system in cities that have been facing flooding due to heavy rainfall events. In Japan, many municipalities have provided financial support for installing household‐level rainwater infiltration and harvesting facilities. However, the use of domestic installations is still limited. This study used the contingent valuation method (CVM) to investigate household preferences for rainwater tanks and a rainwater infiltration inlet (RII) in Yokohama, Japan, and examine the factors influencing the respondents' willingness to pay (WTP). We found that public perceptions of these systems have remained low. The mean WTP was US$265 and US$274 per unit for RII and a rainwater tank, respectively. When compared with the actual market price, the WTP results indicate that respondents had a high interest in these systems. Moreover, income, the experience of flooding and environmentally conscious behaviour were the main affecting factors.

Study on the Aridity in the North-Western (NW) Part of Bangladesh through Combined Application of Remote Sensing, GIS and Geophysical Data

In the present paper, hydro-environmental behaviour of two adjacent but characteristically different land areas of (i) semi-arid Barind Tract and (ii) Ganges flood plain situated in the north-western part of Bangladesh have been studied and possible mechanisms of variability in the two study sites have been investigated. Time series remote sensing data supplemented with climatic, geophysical and groundwater data and other ancillary information have been analysed for the purpose. Coupling of Landsat TM derived vegetation cover information with meteorological data depicts higher sensitivity of Barind Tract than the other study site towards vegetation cover changes in response to rainfall amount. Temporal sequence of albedo value as derived from Landsat TM data manifests appropriate seasonal trend that is consistent with field observations. Analysis of rainfall data over a period of about 50 years depicts substantially higher rainfall in both the study sites as compared to a typical semiarid region. However, temporal distribution of rainfall events is mostly concentrated within very short period of time in the year. Lithological information on the subsurface configuration depicts the existence of a relatively impermeable clayey layer near the top surface in these areas. Relatively higher thickness of this impermeable clayey layer over the semiarid Barind areas has been noticed that slows down the infiltration process significantly as compared to that in adjacent floodplain areas. Analysis of drainage network exhibits relatively higher drainage density in the Barind Tract area as compared to that in floodplain area. The drainage pattern shows predominantly unidirectional and distributary nature of drainage in the Barind Tract area and in general, distribution is oriented towards basin direction and most of the branches of the drainage system. Ultimately, relatively higher elevation, steeper slope result in relatively quicker surface runoff to carry out excess rain water to the nearest basins, results in decreased infiltration of rainwater. Eventually, the conversion efficiency of Barind Tract area to transform intercepted rainwater into underground reservoir water through infiltration seems to be lower as compared to that of floodplain areas.

Effect of reinforcement stiffness on response of back-to-back MSE wall upon infiltration

Back-to-back mechanically stabilized earth (MSE) walls are being widely utilized as bridge abutments and highway ramps, considering their cost effectiveness and ease of construction. Though high quality well-graded granular fill is the most appropriate backfill material, owing to its scarcity, locally available low-quality soils are often used as backfill. Nevertheless, numerous failure cases of such walls with low-quality soil are reported, especially subsequent to rainwater infiltration. The stiffness of reinforcement is a key parameter affecting the overall behaviour of MSE walls. The present study investigates the influence of reinforcement stiffness on the response of select fill, marginal fill, and hybrid-fill back-to-back MSE walls using a finite element (FE) based approach. Results show that stiffness of reinforcement has a significant effect on the overall performance of marginal fill wall upon rainfall infiltration. Specifically, with the increase of reinforcement stiffness, the infiltration-induced facing displacement decreases and reinforcement tension increases. However, the performance of select fill and hybrid-fill walls following rainfall infiltration was found to be satisfactory even with low stiffness reinforcements, and further improvement with increase of reinforcement stiffness was insignificant. The reduction of safety factors during infiltration was shown to be independent of reinforcement stiffness for all wall types.

Typhoon, rainfall and trees jointly cause landslides in coastal regions

Typhoon-induced landslides are the primary natural hazard in hilly coastal regions of South East Asia and can potentially devastate coastal communities and infrastructure. They occur at approximately the same time as typhoon strikes, showing complex failure mechanisms under the coupled action of wind, rainfall and trees. Therefore, special assessments should be performed for such geohazards. Here we elucidated the general features of typhoon-induced landslides in southeast coastal China in terms of their geological characteristics, spatial and temporal distribution, and vegetation cover characteristics. We further established a framework to investigate their possible failure mechanisms coupled to wind, rainfall and trees. Specifically, the mechanical response of trees in a typhoon was estimated through a combination of the autoregressive method (AR) and a multi-degree-of-freedom tree swaying model, while the trees and rainfall contributions were determined by calculating the cohesion attributable to roots and the soil shear strength reduction caused by the water content variation. Our results suggest that the root reinforcement disappears when the sliding surface is below the root embedded depth, and the impact of wind load is significant during the slope stability analysis. The Force 14 wind (mean wind velocity up to 45 m/s) reduces the factor of safety (Fs) of the slope by 20% when blowing downhill, and its combined contribution with rainwater infiltration will lead to a higher risk of slope failures (Fs reduction of 45% at the base of the root-soil composite). Additionally, typhoon-induced shallow slope failures are prone to develop at the base of the root-soil composite or the rock-soil interface. Our model results suggest that the impacts of wind and vegetation on the generation of landslides during a typhoon can be significant and deserve more attention in hazard assessment studies.

Isotopic tracing and quantitative assessment of rainwater in a separate sewer system in Tiszavasvári, Hungary

The hydrological processes that commonly occur within the sewer system i.e., rainwater percolation or groundwater infiltration, can be easily described applying water isotopes. This study investigates the potential of tritium and stable isotope composition (δ2H and δ18O) of water for tracing rainwater entering urban sewer and estimating the amount. The work consists of collecting and analyzing wastewater and rainwater samples over a six-day-long period including a 30-min-long rainfall event, and then applying the isotopic results to determine the mixing ratios in the sewer pipes and the sensitivity of the applied tracing methods. Results reveal that the isotopic composition of wastewater reacts to inflowing rainwater sensitively: detectable flow rate increase resulting from rainfall is 0.62 m3h-1 for tritium, 2.49 m3h-1 for δ18O and 1.25 m3h-1 for δ2H. While applying variation of discharge, these values are 12.15 m3h-1 and 18.91 m3h-1 in daytime and nighttime, respectively. Due to the more positive stable isotope values of precipitation in the summer half-year, isotopic difference of rainwater and groundwater (being less enriched) is more notable, subsequently, traceable amount of parasitic rainwater in case of the examined area is lower than in the winter half-year. In case of groundwater recharged under cold climate conditions sampling should be carried out in summer in the night hours, after an at least three-day-long dry period. Though, all three isotopic tracers applied in this study proved to be suitable to detect small amount of parasitic precipitation, tritium came out as the most sensitive one.