Rainfall Intensity Conditions Research Articles

Rainfall-runoff partitioning in small watersheds of different vegetation types in the loess area based on hydrogen and oxygen isotope tracing.

Recognizing watershed runoff process and its component sources is a prerequisite for the rational use of water resources. To elucidate the effects and quantitative contributions of various vegetation types on the components of watershed runoff, we centered on the Caijiachuan main channel watershed in Jixian, Shanxi and five sub-watersheds with distinct vegetation types. By tracking the hydrological responses to two representative rainfall events and assessing the spatiotemporal variations in hydrogen and oxygen isotope signatures, we aimed to discern disparities in the runoff processes across these sub-watersheds and pinpoint their constituent origins. The results showed that under medium rainfall condition, the contribution rates of event water to the river flow of each watershed were in an order of protected forest (94.3%) > Caijiachuan main channel (83.1%) > agro-pastoral composite (64.3%) > plantation-secondary forest (52.4%) > cropland (0.3%) > secondary forest (0.0%); under light rainfall condition, plantation-secondary forest (52.4%) > protected forest (58.5%) > cropland (40.6%) > secondary forest (15.8%) > agro-pastoral composite (12.5%) > Caijiachuan main channel (9.3%). The event water contribution rate of secondary forest and protected forest watersheds to runoff was higher than that of plantation watersheds. The secondary forests watersheds had a stronger runoff storage capacity. The event water contribution rate of protected forest and agro-pastoral composite watersheds under medium rainfall intensity condition was greater than that under light rainfall intensity condition, while the event water contribution rate of cropland, plantation-secondary forest, and secondary forest watersheds was in adverse. The event water contribution to the runoff of forested watersheds was greater than that of cropland watersheds, which may be related to the presence of silt dams at the mouth of agricultural watershed channels. This study can provide a scientific basis for the analysis of water conservation and runoff change attribution in the loess area of west Shanxi.

How do belowground bedrock fissures impact soil erosion on karst hillslopes under different rainfall intensity conditions?

AbstractIn karst regions, bedrock fissures are developed via karstification, which may cause belowground soil erosion (BSE). However, few studies have quantitatively assessed the effect of bedrock fissures on BSE because BSE measurement is difficult on karst hillslopes. The objective of this study was to investigate the differences in runoff and soil erosion at the surface and belowground on karst hillslopes with and without bedrock fissures (hereafter called HS1 and HS2, respectively) under different rainfall intensities (50, 75, and 100 mm hr−1). The slope gradient was 5°. In the rainfall process, surface runoff (SR), subsurface runoff (SBR), soil–rock interface flow (SRIF), and underground fissure flow (UFF) data were collected on HS1 and HS2. The results showed that the SR coefficients of HS1 and HS2 were negligible (less than 1%) under rainfall intensities of 50 and 75 mm hr−1, and UFF (56%–57%) of HS1 and SRIF (40%–44%) of HS2 dominated the runoff pattern. Under a rainfall intensity of 100 mm hr−1, the SR coefficient increased to approximately 30% under the two treatments, and the coefficients of UFF of HS1 and SRIF of HS2 decreased to 29% and 24%, respectively. Compared to HS2, UFF of HS1 increased by 18%–39%. The SBR coefficient was lower than 10% for all rainfall events. Because SR and SBR were low under rainfall intensities of 50 and 75 mm hr−1, the soil loss was dominated by UFF (99%–100% of the total sediment) of HS1 and by SRIF (86%–97% of the total sediment) of HS2. Under the 100 mm hr−1 rainfall intensity, almost all sediment was lost via SR under the two treatments, and the sediment loss of HS2 was 33% higher than that of HS1. Our results indicated that bedrock fissures caused more underground rainwater leakage at the SRI and further decreased surface soil erosion on karst hillslopes.

An experimental study on the evolution law of roll wave parameters in overland flow

AbstractRoll waves commonly occur in overland flow and have an important influence on the progress of soil erosion on slopes. This study aimed to explore the evolution and mechanism of roll waves on steep slopes. The potential effects of flow rate, rainfall intensity and bed roughness on the laws controlling roll wave parameters were investigated. The flow rates, rainfall intensities and bed roughness varied from 5 to 30 L/min, 0 to 150 mm/h, and 0.061 to 1.700 mm, respectively. The results indicate that roll waves polymerize significantly along the propagation path, and bed roughness and rainfall affect the generation and evolution of roll waves. The wave velocity, length and height decreased with bed roughness, whereas the wave frequency increased with increasing bed roughness under fixed flow rate and rainfall intensity conditions. Rainfall increased the wave velocity and wavelength and decreased the wave frequency. The wave velocity, height and wavelength tended to increase with an increasing flow rate. Rainfall promoted the generation of roll waves, whereas bed roughness had the opposite effect. The generation of roll waves is closely related to the Froude number (Fr) and flow resistance. In this experiment, the range of the Reynolds number for the roll waves generated in the laminar region was 142–416, and the range of the flow resistance coefficient was 0.64–4.85. The critical value of the Fr for flow instability in the laminar region was approximately 0.57. Exploring the generation and evolution law of roll waves is necessary for understanding the processes and dynamic mechanisms of slope soil erosion.

The Impact of Rainfall Movement Direction on Urban Runoff Cannot Be Ignored in Urban Hydrologic Management

Urban floods have been exacerbated globally, associated with increasing spatial-temporal variations in rainfall. However, compared with rainfall variabilities of intensity and duration, the effect of rainfall movement direction is always ignored. Based on 1313 rainfall scenarios with different combinations of rainfall intensity and rainfall movement direction in the typically rainy city of Shenzhen in China, we find that the effect of rainfall movement direction on the peak runoff may reach up to 20%, which will decrease to less than 5% under heavy rainfall intensity conditions. In addition, our results show that the impact of rainfall movement direction is almost symmetrical and is associated with the direction of the river. The closer rainfall movement direction is to the Linear Directional Mean of rivers, the larger is the peak runoff of section. Our results reveal that rainfall movement direction is significant to urban peak runoff in the downstream reaches, which should be considered in urban hydrological analysis.

Simulasi Penempatan Rorak Sebagai Bentuk Pengoptimalan Konservasi Air

Trenching is a form of soil and water conservation engineering that is commonly used and is known to be effective in controlling runoff and increasing water content in the root zone of plants. There are various configurations of trench placement in the field and this study aims to simulate the placement of trench by comparing the three trench configurations to find out which configuration is most effective in capturing surface runoff. The simulation is carried out by calculating the catchment capacity of surface runoff under different rainfall intensity conditions and runoff coefficients in the three trench configurations that have different catchment areas. From the calculation, it is known that configuration 3 in optimal conditions has a comparative advantage of 41.67% - 68.80% (compared to configuration 1) and 27.78% - 52.83% (compared to configuration 2). Meanwhile, configuration 2 has a comparative advantage of 13.89% - 16.06% when compared to configuration 1. From the calculation it is also known that there are conditions where the three configurations will produce a uniform value so that there will be no comparative advantage between the three configurations. This condition is generally above the rain intensity of 50 mm per hour and the runoff coefficient is above 0.45.

Experimental assessment of the relationship between rainfall intensity and sinkholes caused by damaged sewer pipes

Abstract. In several countries, the rising occurrence of sinkholes has led to severe social and economic damage. Based on the mechanism of sinkhole development, researchers have investigated the correlation between rainfall intensity and sinkholes caused by damaged sewer pipes. In this study, the effect of rainfall intensity on the formation of eroded zones, as well as the occurrence of sinkholes caused by soil erosion due to groundwater infiltration through pipe defects, has been analyzed through model tests. The ground materials in Seoul were represented by weathered granite soil, which is generally used for backfill sewer pipes, and groundwater levels corresponding to three different rainfall intensity conditions were considered. The ground level changes and ground displacements were measured continuously, and the particle image velocimetry (PIV) algorithm was applied to measure the displacement at each position of the model ground. The results indicate that impeding the excessive rise in groundwater levels by securing sufficient sewage treatment facilities can effectively prevent the development of sinkholes caused by pipe defects.

Storm runoff generation in headwater catchments on the Chinese Loess Plateau after long-term vegetation rehabilitation

Storm runoff is important for maintaining surface water resources, while this function is significantly affected by land use and land cover changes, e.g., afforestation and reforestation. The Chinese Loess Plateau (CLP) has undergone large-scale vegetation rehabilitation, especially afforestation over the past 20 years. We hypothesize that afforestation has profoundly changed the amounts and mechanisms of storm runoff generation in headwater catchments on the CLP. To test this hypothesis, rainfall, soil moisture, and streamflow were monitored in a grass catchment and an adjacent forest catchment for two consecutive years. The objective of this study was to elucidate the varied mechanisms of storm runoff generation in these two contrasting revegetated catchments. Results showed that (1) average runoff coefficient in the grassland catchment (0.042) was approximately ten times higher than that in the forestland catchment (0.004), confirming the impact of catchment afforestation on the suppression of storm runoff generation. (2) Peak rainfall intensity was the first-order control of the runoff coefficient in the grassland catchment, but not in the forestland catchment. (3) Threshold values for antecedent soil moisture (~18%) and the sum of antecedent soil moisture index and event precipitation (~210 mm) were identified in the grassland catchment, above which storm runoff significantly increased. (4) Two extraordinary high runoff coefficient events were observed in the grassland catchment, one due to high peak rainfall intensity and strong surface runoff and the other due to high rainfall amount and high antecedent soil moisture. We conclude that long-term afforestation has changed the mechanisms and patterns of storm runoff generation, and different conditions of rainfall intensity, rainfall amount and antecedent soil moisture determined the hydrological connectivity between the upper hillslope and downhill gully in the catchment. This study deepens our understanding of the mechanisms and thresholds of storm runoff generation in headwater catchments on the CLP.

Functional traits explain seasonal variation effects of plant communities on soil erosion in semiarid grasslands in the Loess Plateau of China

Improved understanding of the impact of vegetation on soil erosion is critical for identifying effective strategies to use in soil and water conservation. Recently, although the concept of functional identity and diversity has been applied extensively in ecology, few studies have attempted to explore the effects of functional identity and diversity on soil erosion. In this study, the plant functional traits in different periods of a season were measured, and soil erosion was monitored in runoff plots of different types of plant community in the field under actual rain events. The measured plant functional traits were extrapolated to functional identity and diversity on the plant community scale. The impacts of functional identity and diversity on soil erosion in different periods of a season and with different rainfall intensity conditions were analyzed. The results showed that in the early and middle season, functional richness and functional evenness of the plant community play an important role in reducing soil erosion during low rainfall intensity. Plant tensile strength has a great effect on soil erosion at intermediate and high rainfall intensity in the early season. However, at the intermediate and high rainfall intensity in the middle season, plant aboveground parts has the greatest effect on soil erosion. At the end of the growing season, functional divergence is the largest determinant of soil erosion form low to high rainfall intensity. This work can provide insight into the mechanism of soil erosion and provide a valuable reference for plants used in soil and water conservation.

The rainfall erosion mechanism of high and steep slopes in loess tablelands based on experimental methods and optimized control measures

The geological integrity of the Loess Plateau is extremely weak. Following the concept and goal of harmonious co-existence between the human race and geo-environment, first, the high and steep slopes of the loess tableland located in a typical ecological restoration area (in Yan’an city, northern Shanxi) were selected as the demonstration area for studying disaster prevention and control. The research adopted new loess curing agents combined with turf transplant techniques to modify and remediate a loess slope. Considering that indoor artificial rainfall tests have the advantages of controlled initial conditions and rainfall processes, this study carried out several physical experiments under different rainfall intensity conditions (60 mm/h, 120 mm/h, 150 mm/h, and 180 mm/h), revealing the dynamic evolution of loess tableland slope erosion, refining the response relation between subsurface physical and mechanical parameters (pore water pressure and moisture content), surface deformation, and rainfall intensity. Based on the perspective of water control, on the one hand, the experimental results showed that the application of improved loess and new technology can successfully decrease the erosion due to slope runoff. On the other hand, hypotonic materials slow down the vertical infiltration of surface water and prevent soil and water loss. Meanwhile, the practice of turf transplant achieves the goal of ecological restoration.

The Effects of Rainfall Intensities and Duration on SCS-CN Model Parameters under Simulated Rainfall

The Soil Conservation Service curve number (SCS-CN) method has been widely used in rainfall-runoff modelling; however, the direct effects of rainfall intensities and duration, which are major factors in hydrological engineering design, on its parameters (initial abstraction ratio (λ) and potential maximum storage (S), the latter is transformed into curve number (CN)) have seldom been studied. In this study, we chose simulated rainfall experiments on runoff plots (30 mm/h, 180 min; 60 mm/h, 90 min; 90 mm/h, 60 min) to obtain synchronized rainfall-runoff data and calculated the parameters using general model fitting and event analysis methods every ten minutes throughout the duration. The results indicate that the parameters changed with rainfall intensities and duration. S decreased as the rainfall intensities increased. Under the same rainfall intensity, the S increased with the duration overall. The corresponding λ changed with rainfall intensities and duration, and has no obvious relationship under different rainfall intensities. Initial abstraction in the event analysis method is the same as the actual situation and we chose these parameters obtained with the event analysis method as our selected parameters. These selected parameters and the parameters obtained using Fu et al.’s method which was based on the standardized procedure in NEH-630 were evaluated by the Nash–Sutcliffe efficiency (NSE), the percentage deviation coefficient (PBIAS), and the ratio of the root mean square error to the standard deviation of measured data (RSR). The results show that the statistics for the selected parameters satisfied the evaluating standard, and have a better value, while the statistics for the parameters obtained by Fu et al.’s method declined as the rainfall intensity increased, and PBAIS was out of the standard range under 90 mm/h rainfall intensity condition. This indicates that the rainfall intensities and duration have important effects on the parameters of the model, and the parameters vary dynamically with the rainfall intensity and duration. These results could be useful for hydrological design in which engineers consider the return period (i.e., rainfall intensities and duration).

Effects of different functional structure parameters of plant communities on slope runoff in different periods of the year in semiarid grasslands

Research on sustainable use of water resources is needed to ensure food security, limit erosion, and prevent land degradation. Owing to the importance of water conservation to ecosystems, further research on the water conservation functions of different ecosystems is needed. Given the influence on water conservation functions, it is critical to identify environmental factors mediating slope runoff. In this study, the focal study area was the Yangjuangou catchment (36°42′ N, 109°31′ E) of the Loess Plateau in Shaanxi Province, China. Using a trait-based approach, a quantitative analysis was conducted to research effects of the functional structure parameters of plant communities on runoff of grass slopes for different periods of the year under differing rainfall intensity conditions. Results show that in mid-June, which represents the start of the growing season, effects of root traits on slope runoff decrease with increasing rainfall intensity. Slope runoff was found to be mainly affected by various plant functional traits in late July and aboveground parts of plants in early September. Given that few studies have focused on runoff processes using a trait-based approach at the community scale, this research can serve as a new reference for investigating the relationship between slope runoff and vegetation.

Rainfall analysis in the Indian Ocean by using 6-States Markov Chain Model

In this study, we used Markov chain approach to analyze rainfall dataset from one buoy (4N90E) in the eastern Equatorial Indian Ocean. This study aims to determine the opportunity for transition (displacement) of daily rainfall intensity, where there are six states or conditions of rainfall intensity, i.e. no rain, very weak, weak rain, moderate rain, heavy rain, and very heavy rain. The Markov Chain method used is the Chapman-Kolmogorov equation and the steady state equation. The investigation of the 6-states in Markov chain model show that dynamic probability of transition state for rainfall data is reflexive properties majority. By using the model, it is concluded that the transition rate matrix of the largest transition probability in the area of 4N90E occurs at the transition from state-1 to state-1 as much is 0.72 and state-2 to state-2 is 0.60. The transition probability value becomes 0.5184 and 0.36 for the same state dominant of two periods P2. The use of the 1st order Markov chain is better than 2nd order.

Rainfall infiltration simulation on embankment containing soluble material

Recently, mixtures of low-quality soil together with solidification materials, such as cement or steel slag, have been used for earthmoving construction. Solidification materials can improve consistency, shear strength, stiffness, and other parameters of low-quality soil by generating bonding forces between soil particles and changing grain size gradation. However, these solidification materials also contain chemical agents. In this study, simulations of rainfall infiltration into embankment constructed with the soil-solidification material mixture are conducted using the soil/water/air/soluble material coupled finite element analysis code, DACSAR-MP_ad. This analysis code can express not only deformation and seepage for an unsaturated earth structure but can also concurrently model the dispersing behaviour of soluble material. Herein, permeability and rainfall intensity conditions are provided and their effects investigated. Consequently, this study succeeds in expressing different distributions of soluble materials within embankment under different rainfall conditions.

Stability Analysis of Slopes on Both Sides of Highway in Geotechnical Area under Rainfall Conditions

The objective of this study is to correctly analyze the slope stability, strengthen the guidance of engineering construction, and ensure the safety of people’s lives and property. In this study, the numerical simulation software Geo-Studio is used to simulate the stability variation rules of the slope on both sides of the highway in the rocky region when the angles of the upper and lower slope of the platform width are changed under the action of light rain for a long time respectively, and the corresponding comparison analysis is made with the corresponding natural working condition. The results show that the infiltration of rainwater has a great influence on the slope on both sides of the highway in the geotechnical area, which is mainly reflected in the decrease of the stability of the multi-level slope, the significant change of the sliding surface (including the location, size, shape, etc. of the sliding surface), the potential instability form of the slope (overall stability and local stability), and the slow but continuous change of the pore water pressure in the soil. Through the rainfall test on the highway slope, it is found that the instability mechanism of the slopes on both sides of the highway in the geotechnical area is affected by the conditions of rainfall intensity, rainfall duration, cumulative rainfall capacity, and rainfall patterns. In addition, the changes of rainfall infiltration rate in the side slope of highway in rock and soil area and the migration rules of water field in side slope are also obtained. The findings of this study can be used as a reference and basis for engineering design and construction. Moreover, the safety coefficient of the slope after renovation meets the stability requirement. Therefore, the slope engineering treatment measures on both sides of the highway can effectively deal with the hidden disaster brought by landslide deformation or instability.

Role of underground leakage in soil, water and nutrient loss from a rock-mantled slope in the karst rocky desertification area

Leakage loss of soil and water is the main reason for karst rocky desertification, and the concomitant nutrient loss/leakage carried by soil and sediment is an important factor that affects groundwater quality. Due to the difficulty in measuring the underground leakage of soil water, the amount of nutrient loss/leakage on a karst slope is currently unknown. A karst slope farmland is simulated in a laboratory based on field investigations in slope farmlands in a karst plateau region in Guizhou Province, China. Rainfall experiments were conducted to determine the surface losses and underground leakages of soil, water, nitrogen, phosphorus, and potassium, as well as the effects of rainfall intensity and slope on these factors in karst slope farmlands. Surface runoff occurs only at rainfall intensities greater than 30 mm/h, but underground runoff occurs under all rainfall intensity conditions. Moreover, underground leakage loss is the main mode of water loss. Soil loss on a karst slope farmland is a process that transitions from underground leakage to surface erosion as the rainfall intensity increases. The concentrations of total nitrogen (TN), total phosphorus (TP), and total potassium (TK) in surface runoff increase with increasing rainfall intensity and decrease with increasing slope gradient. The total loss loads of TN and TK in runoff and sediment increase with increasing rainfall intensity or slope gradient. The total nutrient loss loads of TN and TP are dominated by runoff losses, but the TK loss load is dominated by sediment losses.

Rainfall thresholds for shallow landslides based on physical models: application in a sub-basin of the Valle de Aburrá (Colombia)•

An analysis of the rainfall conditions and the influence of the infiltration processes on the slope stability are important in tropical mountain terrains due to the wide occurrence of rainfall-induced landslides. Distributed physical-based models can be coupled with techniques that relate the factor of safety with rainfall thresholds associated with the occurrence of this phenomenon. This study presents a methodology that determines the thresholds of rainfall intensity and duration, for the prediction of shallow landslides, using a distributed physical model called TRIGRS. In the analysis, it is used a percentage of the critical area of failure defined for a study area. The conditions of mean intensity and duration of rain that induce this failing area to be reached are adjusted to a potential equation, within certain ranges of duration and intensity. The model is used in a sub-basin of the Valle de Aburrá (Colombia) and the results are compared with rainfall thresholds defined with another distributed physical model. The obtained results reaffirm that the conditions of rainfall intensity and duration that trigger landslides in a region exhibit scaling properties determined by relationships of potential equations, like those obtained by other researchers in different places of the world.

A finite element study of rain intensity on skid resistance for permeable asphalt concrete mixes

Safe highway operations are one of the major concerns of pavement engineers and authorities. The reduction of skid resistance during rainy weather poses high risk for safe driving. Wet skid resistance varies under different rainfall intensities and is influenced by many factors such as permeability of asphalt material, pavement geometric design, and tire operating conditions. Empirical studies could offer useful understanding of mechanisms of wet skid resistance and its influencing factors, however, the applicability of the empirical relationships are restricted as soon as there is a change in one of the relevant factors. In recent years, the advancement of the finite element tools has enabled researchers to simulate the tire-fluid-pavement interaction in a more realistic way. However, to the best of the authors’ knowledge, the current available numerical models either do not include the real microstructures of the pavement or ignore the water infiltration through the pavement voids in the simulations. Therefore, this paper aims to providing a numerical tool to evaluate the wet skid resistance at various rainfall intensity conditions considering the effects of pavement geometric design, tire tread design and tire operating conditions. The surface characteristics and porous microstructures of the pavement are included in the model in a way that both the vertical water flow into the asphalt concrete and surface flow on the pavement can be captured in the simulation. The effects of several pronouncing influential factors as mentioned above are quantified. Such a model upon validation is expected to provide an easy and reliable tool for pavement engineers to evaluate wet skid resistance under rainy weather more accurately which can be incorporated into pavement management systems for safety highway operation.

Partition-coordinated control of soil and water loss for chestnut forests in the Yanshan Mountain Region, China

Soil erosion from chestnut forests is one of the most important factors causing land degradation in the Yanshan Mountain Region. A 2-year field study was done to compare the effects on erosion of a control plot (CP), a repaired and maintained horizontal ditch built with an engineering baffle every 6 m (MP 1), and a repaired and maintained horizontal ditch built with an engineering baffle every 8 m (MP 2). The results showed that the slope runoff of chestnut forests was influenced by rainfall characteristic factors. No single rainfall characteristic factor showed dominance for hill slope runoff. The runoff reduction effect of the partition-coordinated erosion control measures (MP 1 and MP 2) was substantial for chestnut forests under high rainfall intensity conditions. However, the runoff reduction efficiency was higher under the conditions of heavy rainfall and low average rainfall intensity than for storms with higher intensity and lower total rainfall. The reduction effect of the partition-coordinated erosion control measures on the runoff and sediment yield of chestnut forest slopes was MP 2 > MP 1 > CP. The runoff reduction rate and erosion reduction rate of MP 2 reached 61.70% and 97.41%, respectively, and that for MP 1 was 54.15% and 85.31%, respectively. Therefore, after a comprehensive comparison, MP 2 was determined to be more effective for soil erosion control for a sloping chestnut forest.

Modeling aggregate size distribution of eroded sediment resulting from rain-splash and raindrop impacted flow processes

Soil susceptibility to detachment and transport sub-processes of erosion is generally controled by the aggregate breakdown mechanism. Measuring particle size and aggregation to the estimate erodibility potential of soils is important under erosive rainfall conditions. The Aggregate Size Distribution (ASD) is one of the most important determinants of soil structure along with soil organic matter content for describing the efficiency of applied, sustainable management strategies. This study aimed to compare the performances of three different aggregate size distribution models to predict the characteristic aggregate size parameter (median diameter, D50) for eroded sediment from interrill erosion processes of Rain-Splash Transport (RST) and Raindrop Impacted Flow Transport (RIFT). The ASDs of 1143 collected sediment samples from the RST and RIFT processes were measured and modeled by the Log-normal, Fractal, and Weibull approaches. The D50 value, as a characteristic parameter for aggregate size distributions, derived from the cumulative ASD curve was compared for soils from different land use types and different slope and rainfall intensity conditions. The performance of each model was evaluated using the Mean Square Error (MSE) and Coefficient of Determination (R2). The Weibull approach was the most accurate model showing the best fit with the lowest MSE values (0.0002 ≤ MSE ≤ 0.0048) and having the greatest R2 values (0.936 ≤ R2 ≤ 0.998) when compared with the Log-normal and Fractal models. Herewith, for semi-arid land use and soil, specific shape and scale parameters for the Weibull distribution, the respective ASDs were successfully re-generated for modeling the eroded sediment of the simulated RST and RIFT interill processes.

Numerical Investigation on Infiltration and Runoff in Unsaturated Soils with Unsteady Rainfall Intensity

Modeling infiltration into soil and runoff quantitative evaluations is very significant for hydrological applications. In this paper, a flow model of unsaturated soils was established. A computational process of soil water content and runoff prediction was presented that combines an analytical solution with numerical approaches. The solutions have good agreements with the experimental results and other infiltration solutions (Richards numerical solution and classical Green–Ampt solution). We analyzed the effects on cumulative infiltration and runoff under three conditions of rainfall intensity with same average magnitude. These rainfall conditions were (Case 1) decreasing rainfall, (Case 2) steady rainfall, and (Case 3) increasing rainfall, respectively. The results show that the cumulative infiltration in Case 1 is the highest among the three cases. The cumulative runoff under condition of Case 3 is smaller than that of decreasing rainfall at the initial stage, which then becomes larger at the later stage. The time of runoff under the conditions of Case 1 is earliest among the three rainfall conditions, which is about 50% earlier than Case 3. Therefore, project construction for urban flood control should pay more attention to urban flood defense in increasing rainfall weather than other rainfall intensities under the same average magnitude. The approaches presented can be utilized to easily and effectively evaluate infiltration and runoff as a theoretical foundation.