Amount Of Rainwater Research Articles

Risk of Flash Floods in Urban and Rural Municipalities Triggered by Intense Precipitation in Wielkopolska of Poland

This research analyzed interventions of State Fire Service (SFS) units in the Wielkopolska region of Poland that were triggered by extreme precipitation for the period 2010–2021. Our results demonstrated that the most populated and urbanized towns in the Wielkopolska (Greater Poland, west of Warsaw) region are at the most risk in the event of extreme precipitation occurrence as measured by the total number of interventions made by the SFS. The number of SFS unit interventions in towns, standardized to 10,000 inhabitants, indicates that the highest proportional volume of interventions also occurred in smaller towns. In the rural municipalities the number of SFS unit interventions increases along with higher population density and proportion of infrastructure areas. As analyzed in this study, the 12 years from 2010 to 2021 were characterized by a higher number of days with heavy precipitation, for example, 20, 30, 40, and 50 mm, in comparison to the previous periods 1961–2010 and 1981–2010. Intervention databases collected by emergency services are a valuable source of information for hazard mapping. Based on those and other available data, a statistical model was created and factors influencing the local and regional occurrence of interventions were determined. Increasing suburbanization, the rising proportion of impermeable surfaces, and the impact of climate change are of considerable importance in urban flood risk. It is necessary to help municipalities develop abilities to absorb larger amounts of rainwater.

Influence of polycyclic aromatic hydrocarbons on water storage capacity of two lichens species

Abstract The wide variability in functional traits that enable the cosmopolitan distribution of lichens often includes the water storage capacity, S, of their thallus. Lichen S in forest canopies can be large enough to intercept and evaporate significant amounts of rainwater, contributing to the runoff-reduction ecosystem services provided by urban forests; however, S is likely influenced by the presence of air pollutants (polycyclic aromatic hydrocarbons, PAHs) in urban areas. PAHs, being both chemically hydrophobic and damaging to lichen thalli, are expected to reduce lichens’ S and, thereby, limit their contribution to hydrologic ecoservices of urban forests. Hence, the relationship between PAH accumulation and rainwater uptake was examined for two lichen species, common in urban forests around the world – Platismatia glauca and Pseudevernia furfuracea. Samples were collected from an area of low air pollution and another area in a highly urbanized city centre with high air pollution exposure (Kraków, Poland). Lichen S was determined using laboratory-simulated rainfall. PAH bioaccumulation differed between species and among the samples from clean and polluted environments. After exposure to polluted air, the concentration of PAHs was higher in P. glauca than P. furfuracea. Samples from the non-urban setting, however, showed no differences between the two species. In the case of P. glauca, S decreased from 35.8% in samples from clean environment to 8.3% after six months of exposure in the urban setting. The respective S values for P. furfuracea were 25.4% and 12.4%. Results strongly suggest that PAH exposure reduces S in both lichen species. The obtained results are important both in ecohydrology and microclimatology and are part of the research on the condition of urban forests.

Assessment of the Quantity of Harvested Rainwater in IGAH Communities of Olamaboro Local Government Area of Kogi State, Nigeria

Abstract: This research is aimed at assessing the quantity of harvested rainwater in Igah Communities of Olamaboro Local Government Area of Kogi State, Nigeria. Data were collected through the use of questionnaire, interview and secondary data sources. Stratified random sampling was employed in the sampling of the respondents. Three hundred and ninety five copies of questionnaire were determined using Taro Yammane and administered, while three hundred and seventy two of them were completely returned. The data generated were statistically analysed through the use of descriptive and inferential statistical tools. Principal Component Analysis (PCA) was employed to collapse the various variables responsible for the quantity of rainwater consumed into few underlying dimensions. Results obtained from the statistical analysis revealed that the mean rainwater consumption per person per day of 8.2 litres is far below the WHO recommended standard. Other results revealed that seasonality of rainfall, cost of constructing storage facilities and household size, limited financial capacity and geographical location are responsible for the existing rainwater quantity obtained in the area. Conclusions were drawn from the results, while the major recommendation was on the need for further investigation into water scarcity situation in the study area.

Unmanned aerial vehicles for planning rooftop rainwater harvesting systems: a case study from Gurgaon, India

Abstract Rooftop rainwater harvesting systems (RRWHS) effectively provide water access by storing precipitated water. The amount of water harvestable using these systems is proportional to the availability of rooftop areas in the region. The use of satellite imagery has gained traction in recent times considering the challenges in conducting a manual survey to determine the rooftop area. However, the limitations on spatial resolution impaired stakeholders from conducting similar assessments in areas with small residential units. In this regard, the use of unmanned aerial vehicles (UAVs) providing high-resolution spatial imagery for the delineation of rooftops of all scales has become popular. The present study is an attempt to utilize UAV-generated orthomosaics to estimate the harvestable quantity of rainwater for setting up an RRWHS. A study area in the Gurgaon district, India, is selected, and the steps involved in estimating the quantity of water harvestable using UAVs are demonstrated. In addition to these computations, a suitable site for constructing the storage unit is identified with the aid of a weighted overlay technique implemented using a Geographic Information System. The results from the study show that nearly 11,229 m3 of water can be harvested per year in the study site using the RRWHS.

Using Soil Water Balance to Estimate Recharge of Underground Water in Central Sulaimani Province

In this study, we estimated the recharge of underground water by using soil water balance in the Sulaimani Province. Based on recorded data in three metrological centres, including Sulaimani, Bakrajo, and Bazyan from 2009 -2021. We found an estimated rate of potential evapotranspiration by using the FAO-Penman -Monteith equation by CropWat Ver.8 Software Programs. Based on this estimate, we found the water deficit and water surplus months in the study area. Moreover, grounded on (SCS-CN) model in the mentioned area which would be divided into 8 different ( CN). Accordingly, an estimate was obtained for the rate of runoff water per month of a calendar year. Finally, we found the amount of rainwater that would take part in the recharge of underground water throughout each month and over years. In this study, we also used statistical analysis of quantitative mathematical results to find amounts of underground water in the study area. Besides, we used (ArcGis10.8) program to create maps for various purposes. In conclusion, we successfully discovered that it is possible to develop a scientific strategy to collect rainwater and replenish underground water sources and protect them by finding out amounts of underground water recharge in the Formation zone that would be 104.2 mm. Importantly, (CN-57) which is located in the district of Bazyan (Khormala -Sinjar Fn.) has the highest amount of underground water recharge that is equivalent to 210.2mm of the total amount of the precipitation equivalent to 32% of the annual sum of rain.

Rain Water Harvesting Technique Implementation for the Chhadvel Korde Village, Maharashtra

Water is one of the most important resources on Earth. In every way, water is crucial to our daily existence. The amount of water that is available in cities is never enough to meet the entire demand. We must rely on water from underground sources because surface water is not readily available. The amount of rainwater that soaks into the subsurface and replenishes ground water has significantly decreased as a result of rapid urbanisation. In this instance, there must be additional supply to satisfy the demand. When it rains, pure rainwater can be gathered "wherever it falls" to instantly replace the water supply. The act of gathering and organising rainwater in a systematic way for later use is referred to as "rainwater harvesting". Two types of rainwater harvesting that could be used in the research region are rooftop and surface runoff harvesting. By adopting a rainwater harvesting system and constructing natural percolation pits, the groundwater level, soil moisture, and soil fertility can all be increased for plantations. Therefore, using this simple strategy typically leads to more vegetation, which raises the aesthetic value. This article examines every rainwater harvesting system established in the Maharashtra district of Sakri in Chhadvel Korde.

Determination of Rainwater Harvesting Potential: A Case Study from Ege University

Rainwater is a valuable resource that provides numerous benefits. The necessity of collecting and reusing rainwater has increased in cities where the effects of climate change are prominent. With little effort and a relatively high initial construction cost, harvesting rainwater can be a cost-effective benefit. In addition to its economic benefits it is an environmentally friendly process that prevents the rainwater from going to waste. In this research the roofs of 24 buildings in an area around Ege University Central Campus (Izmir, Turkey), which has a Mediterranean climate, were selected for a pilot project. The amount of rainwater to be harvested was calculated to be 16.570,30 m3. This study determined that the potential rainwater to be harvested from the research area throughout the year could provide 11% of the water required for irrigation of the existing green areas throughout the year and 20% of the water required for irrigation from April to October. Therefore, considering the ratio of the potential rainwater that was harvested during the summer season to the potential rainwater amount that could be harvested throughout the year, this experiment showed the potential benefits of storing the harvested rainwater in the rainy spring and winter seasons throughout the year.

POTENSIVENESS OF WATER RESOURCE MANAGEMENT

No living thing can thrive without water; it is the environment's lifeblood. Water has a special function in the growth of all economic sectors in every nation. Water is utilised for a variety of things, including agriculture, domestic consumption, industry, and the production of electricity. However, improper use of water resources results in extensive soil degradation, disrupts the supply of drinkable water, and produces significant economic loss. Therefore, it becomes vital to use science and technology to harness the water resources that are already present on Earth. The case study described in this article illustrates how substantial amounts of rainwater can be used to replenish groundwater supplies.Ongole is a tiny village that is 10 kilometres from District centre. It is intended to implement such biological and engineering controls that will divert this additional runoff to groundwater storage. The work's most important aspect is that, if similar technologies are created and widely used in rural areas, hundreds of villages across the nation won't need tankers to provide water to them. Additionally, this will aid in the economic development of the villagers, which is mostly brought on by water scarcity.

CORRELATION AND REGRESSION RELATIONSHIPS OF PARAMETERS OF RAINWATER DRAINAGE FROM ROADS

<p>In order to find the optimal solution for the drainage of rainwater from roads in urban areas, as well as for the evaluation and ranking of conceptual solutions, appropriate mathematical models and software packages were used in this research. For relevant rain episodes, i.e. rainfall of appropriate duration and intensity, runoff coefficients and flows were taken into account and analyzed according to the rational method, all for the purpose of obtaining data on the amount of rainwater entering the sewage system. Through this research, very good correlations and regressions were established between the cross slope of the road and the parameters of rainwater drainage from the road, as well as the correlation and regression relationships of the cross slope of the road and the efficiency of the drain. Likewise, the dependences of the drainage parameters, the efficiency of the drains and the cross slope of the road were determined, expressed through mathematical functions.</p>

Flash flooding hazard assessment, modeling, and management in the coastal zone of Ras Ghareb City, Gulf of Suez, Egypt

The assessment of flash flood hazards in the coastal zone of Ras Ghareb City (RGC), Red Sea, Egypt, was accomplished through the use of GIS tools and the spatial multi-criteria approach. The presented work aims to assess, integrate, and generate potential flash flood hazard maps. The analytic hierarchy process was utilized to calculate weights of hazard and vulnerability of flash flood controlling factors and their parameters such as topographical, geological, and hydrological factors. In addition, the risk degree of each specific basin and its sub-basins is estimated by combining standardized parameter values. Despite its location in an arid region, the basin may receive a large amount of rainwater, which can cause flash floods at the basin's outlet. Recently, flash flooding took place in the coastal region of RGC in October 2016 and September 2020, resulting in the loss of many human lives and catastrophic effects on local infrastructure and surrounding environments. According to reports from Hurghada, Red Sea Governorate, the RGC experienced exceptional flooding that exceeded 120 million cubic meters as a result of 51 mm of rainfall. Based on the remote sensing satellite data such as Aster Digital Elevation Model (GDEM) and the GIS tools, the basin and sub-basin drainage patterns were delineated and compared with reference topographical map sheets of a scale of 1: 50,000. The sub-basins have been isolated and morphometrically studied to determine vulnerability to flash flooding. In addition, the flash flood threat model was developed using geoprocessing tools provided by ArcGIS software to incorporate all contributing factors spatially. The flash flood risk in the Ras Ghareb (RG) basins and their sub-basins has been identified and classified into three classes (high, medium, and low hazard degree). High and moderate flood-risk basins require comprehensive studies to introduce measures to protect certain areas from flood danger. Finally, the GIS and the spatial multi-criteria analyses were effective ways to carry out a flash flood management system in order to support the decision-makers by recommendations to conserve and mitigate the possible flash flood hazards in the study areas.

Repong Damar as a Mitigation Effort for the Ulun Saibatin Landslide Disaster in the Regency of Pesisir Barat

The background of this research is that Pesisir Barat Regency is prone to landslides, so that landslide disaster mitigation efforts are needed using the local wisdom of RepongDamar. The purpose of this study was to determine the role of RepongDamar in landslide disaster mitigation. The method used in this study is a qualitative method with a descriptive approach. The results of the study describeRepongDamar's role in landslide disaster mitigation efforts includes the role of the canopy as a water reservoir, thereby reducing the amount of rainwater that reaches the ground. The second role is that large roots will have a grip on the soil which can reduce the possibility of soil movement and increase the shear strength of the soil. The third role, evapotranspiration plays a role in reducing soil saturation, so that water does not accumulate in the impermeable layer. The existence of RepongDamar will minimize the occurrence of erosion, because RepongDamar has woody trees that have strong roots such as damar, duku, petai, jengkol, teak and durian trees.

Assessment of shallow groundwater contamination on Pari Island, Indonesia.

Freshwater on small islands is generally limited and relies on rainwater and groundwater. This study aimed to assess changes in shallow groundwater quality on Pari Island, Indonesia. Pari Island is a small island with an area of 41.32 ha and belongs to a monsoon climate. Also, being a residential island, it attracts many tourists. The approach was to assess the shallow groundwater quality of ten wells during the dry and wet seasons. Changes in water quality were evaluated using traditional hydrochemical analysis methods (Schoeller, Piper, and Gibbs diagrams) and ion ratios. Shallow groundwater quality in the study area showed different responses depending on the season. Therefore, each well responded differently to changes represented by changes in water quality. The change is controlled by various factors: evaporation (or water balance), geology, aquifer characteristics, tides, wind direction, and wave height. These factors trigger the fluctuation of groundwater and seawater interface, affecting the amount of rainwater and seawater transported to the freshwater aquifer layer. This water volume transported affects the process of rock weathering, dissolution, and dilution of contaminants in shallow groundwater.

An Alternative Source of Water Supply: Design and Construction of Rainwater Harvesting System for Domestic Use in Ovia-North East Local Government Area, Benin City, Edo State, Nigeria

Demand for freshwater is on the increase due mainly to population growth and urbanisation. Many of the water systems that keep ecosystems thriving and feed a growing human population have become stressed. Rivers, lakes and aquifers are drying up or becoming too polluted to use. Hence, there is need for alternative water supply sources. With this in mind, there has been a growing attention on the potentials of rainwater harvesting as an alternative source of water supply. In this study, rainwater harvesting (RWH) system was designed for a 5-membered household in Ovia-North East LGA of Benin City, Nigeria. However, a prototype of the RWH system (mini system) was constructed to ascertain its suitability. It consist of a corrugated metal (zinc) sheet catchment of 6m 2 , a collection system made of PVC pipes and a filter with granular activated carbon and fine sand and two locally available plastic storage drums having capacity of 100L each. Rainwater samples were collected from the storage drums and analysed for their suitability in domestic purposes. These samples were analysed for thirteen parameters, namely; pH, Electrical Conductivity (EC), Temperature, Turbidity, Total Dissolved Solids (TDS), Chloride (Cl), Ammonium Nitrogen (NH 4 N), Nitrite (NO 2 - ), Nitrate (NO 3 - ), Iron (Fe), Zinc (Zn), Copper (Cu) and Coliforms Count (Col.) using standard methods. Results revealed that with a roof area of 40m 2 , 75m 3 reservoirs or tanks capacity will be required for dry period. It was observed that all parameters analysed were within acceptable limits for drinking water quality except for coliform bacteria. Although minimum level of coliform bacteria was observed, however pure water should be free from all kinds of coliforms, thus it is recommended that the addition of a disinfectant to the harvested rainwater is required to further improve it quality for domestic use. Also proper maintenance of the catchment area and storage containers could eliminate the presence of coliform bacteria and make rainwater safe for domestic purposes. This study has revealed that the harvested rainwater is of good quality and that the amount of rainwater to be stored with a 75m 3 reservoirs or tanks will be more than enough for a 5-membered household to meet its domestic use throughout the whole dry periods of the year. Hence, RWH can serve as an alternative and viable source of water supply. Keywords: Catchment Area, Collection System, Runoff coefficient, Rainwater Harvesting, Rainfall, Water Demand, Water Supply. DOI: 10.7176/CER/14-7-01 Publication date: November 30 th 2022

Analysis of the impact of the degree of catchment sealing on the operation of drainage system

With increasing sealing of the catchment surface, the time of outflow of water from the catchment decreases and the volume of surface water flowing out increases. This phenomenon has a negative impact on the water balance of the catchment area, and results in an increase in the frequency of flooding, related to inability of the existing drainage systems to collect the surface waters. This paper presents the results of modeling of hydraulic conditions in a selected part of the storm sewage system. The US EPA’s software SWMM 5 was applied to our studies. Three different rainfall events of various intensity and time and variable sealing degree of the catchment surface were studied in our research. The conducted simulation tests enabled the analysis of the sewage flow rate, the canals filling height as well as assessment of the impact of changing the degree of surface sealing on the amount of rainwater discharged and the frequency of outflows.

Synergetic roles of dynamic and cloud microphysical processes in extreme short‐term rainfall: A case‐study

AbstractBoth dynamic and cloud microphysical processes play significant roles in the intensity of severe rainfall within a convective storm. In this study, a quantitative analysis has been performed to investigate dynamic and cloud microphysical contributions to extreme hourly rainfall (EHR) with the peak value of 201.9 mm in Zhengzhou City, China, on 20 July 2021. It is found that the EHR is generated by the overlay of rainwater provided by both dynamic delivery and cloud microphysical production within a meso‐γ‐scale convective storm over Zhengzhou. Specifically, part of the rainwater is directly produced by cloud microphysical processes over the EHR region. More importantly, considerable rainwater, which is produced in the front of the storm associated with strong updraughts, is delivered into the EHR region. The dynamically delivered rainwater overlays the rainwater produced by cloud microphysical processes, forming a deep layer with a large amount of rainwater over the EHR region. As the massive rainwater pours down within a short time, EHR is formed. It should be highlighted that the dynamic delivery plays a decisive role in EHR formation, although sometimes EHR can be generated mainly through cloud microphysical production in the case of weak dynamic delivery. Concerning the cloud microphysical processes, the collision of cloud droplets by raindrops produces the largest amount of rainwater, followed by graupel melting. Linking the EHR with dynamic and cloud microphysical processes within a convective storm, a new light on further understanding and forecasting of short‐duration extreme rainfall would be shed.

Assessment of the Women‘s Participation to Disaster Preparedness and Response in the Municipality of San Juan, Batangas

In the Province of Batangas, Municipality of San Juan, Batangas is regarded to be vulnerable to disaster. It has coastal, upland and populated lowland geographical areas. In the fortuitous event of catastrophe, women are deemed the frailest among the marginalized sectors. While the Magna Carta of Women gives women the right to protection and security in terms of disasters, specialized needs of women may be overlooked, gender-blind and insensitive to the development actions. This study assesses the participation of women to disaster preparedness and response in the Municipality of San Juan. Research surveys states that in the event of fire, traumatic experiences of people affected therein got the highest weighted mean of 3.3640. In terms of flood, the highest weighted mean is 3.4740, where flood is caused by the large amounts of rainwater, which cannot be absorbed in to the ground, drainages and canals. Relative to typhoon, the highest weighted mean is 3.4260, an intense circulation of the weather system causes typhoon over tropical seas and oceans accompanied with very strong winds, heavy rains and large ocean waves. About landslide, it is triggered by other natural hazards such as prolonged, heavy rainfall, and typhoon or by other sources of water, which increases the water content of the slope materials and got the highest weighted mean of 3.4200. Regarding earthquake, the highest weighted mean is 3.370, where earthquake is caused by sudden slippage of rock masses below or at the surface of the earth. In terms of participation in disaster preparedness and response, the lowest weighted mean is 2.3380, it is where women slightly or sometimes participate in forming and mobilizing women’s group in the local government units during disaster to protect and meet the necessary needs of women. Based on findings, the extent of participation in disaster preparedness and response practices in the Municipality of San Juan, Batangas is significant and highly important on the assessment of the respondents regarding disasters and their empowerment is necessary in developing a disaster resilient community. Thus, this study serves as basis for the determination in policy-decision making process necessary to address and integrate the specialized needs of women in the Municipality of San Juan, Batangas relative to participation to disaster preparedness and response.

Methodology to Optimize Rainwater Tank-sizing and Cluster Configuration for a Group of Buildings

The behavior of a rainwater harvesting system depends on some variables that cannot be controlled, such as rainfall, building roof size and water consumption. The selection regarding rainwater tank-size will affect the performance of the system and the cost–benefit ratio. The criterion employed for this selection is based on the need for volume-storage and typically, yield large-sized rainwater tanks, especially when the amount of rainwater is higher during rainy seasons. This article presents a methodology for modelling rainwater harvesting, storage, and water consumption, for different configurations of a set of buildings, called clusters, where all buildings collect, store and consume water. This methodology allows for analyzing with different indicators, what is the best recommended configuration and tank-sizing, based on configuration and storage ratio exhibited, thus avoiding the situation of being underutilized. The proposed methodology is applied to a case of study at a university, in Mexico City. In this study case, the dynamics per day is modeled over a year, considering monthly rainfall averages, over 2 groups made up out of 4 buildings with different collecting capabilities and consumption each, allowing for the analysis of 9 cluster configurations and 4 rainwater tank-sizing dimensions. The results are analyzed by means of annual indicators such as: the decrease in the volume used from the public water network, the days of autonomy of the system, and a coefficient \(R\) (which relates the volume spilled to the empty volume). This coefficient is then used selection regarding rainwater tank-sizing and the most recommended cluster configuration.

Consideration of atmospheric rainwater quality parameters for business purpose: case study a suburban area in Durres, Albania

This study considers the possibility of using atmospheric rainwater for business purposes in the city of Durres, Albania with a population of 205 thousand inhabitants living in an area of 432 m2. Untreated rainwater which is used for business purposes, was analysed for water quality based on twelve months of monitoring data. From May 2021 to May 2022, rainwater samples were taken by analysing the quantity and quality parameters. Samples were collected from different points within a rainwater harvesting systems we had installed in a business serving as a vehicle service. In order to evaluate the quality of atmospheric water were measured physic - chemical and bacteriological parameters of rainwater. Also, with the help of water meters we measured the amount of rainwater precipitation for a year collected in water tanks that we have installed in this business. From the measurements has result that the average amount of rainwater collected was 46 500 litres/year of water. This amount does not meet all needs of this business, but facilitates a lot their requirement for technological and sanitary usage. The performed physic - chemical and bacteriological analyses showed that the parameters were within the standards. Faecal Coliforms, Escherichia coli (E. coli) and faecal Streptococcus were not found in any sample. Results show that the untreated rainwater could be used directly for technological and sanitary purposes.

RAIN WATER HARVESTING: A LITERATURE REVIEW

About 70 percent of the earth is water. Despite this, if the people living in the remaining 30 percent area are facing its shortage, then it is necessary to know the reasons behind it. Merely knowing these reasons by a few sections of the people is not going to change anything because the existence of water element in nature is going to be constant. If there is a shortage of water in 30 percent of the area, it does not mean that it is getting destroyed from there. Rather, it means that somehow it is getting from there in 70 percent part. The scope of human life is in 30 percent of the earth, it is a serious and shameful thing for the human being to let the water go somewhere else, not caring about it and getting into trouble himself. The sources of water are on the surface, the ground and the sky, and any disturbance from anywhere in this range can affect a very large area. But such disturbances can be fettered only when 30 percent of the people have an intuitive understanding of these disturbances. Along with development, increasing demand for water like other resources is a normal process. Due to increase in population, urbanization, change in living habits etc., the pressure on groundwater is increasing, whose effect is clearly visible in many areas in the form of decline in groundwater level and quality. The availability of water in any region of India depends on the geographical conditions and the amount of rainwater there. But, in this period of development, rapid changes are being made in the geographical structures, the resources are increasing rapidly. Consumption/utility and extinction of various water resources have changed the dimensions of water availability. Now the effect of all ecological dimensions on the water is becoming important. On the other hand, the word pollution has become common to all the areas. Along with the development, some of the relevant effects of the industrial revolution at the global level are constantly taking a formidable form in the form of pollution. Due to this the scope of pollution of water of wells, ponds, rivers, even ground water sources are increasing day by day. The considerable concern is being expressed about the pollution of large parts of the water in these circumstances.

Application of the Reformulated Gash Analytical Model for Rainfall Interception Loss to Unmanaged High-Density Coniferous Plantations Laden with Dead Branches

Interception loss (IL) by the forest canopy removes a substantial quantity of rainwater within forested ecosystems. The large-scale unmanaged Japanese coniferous plantations with high stand density (SD) in Japan raise concerns about an additional increasing IL as a result of a new influential factor of dead branches under canopies. Thus, evaluating the usage of IL estimation models is vital to regulating the water and environment in such coniferous plantations. This study aimed to examine the applicability of the reformulated Gash analytical model (RGAM) to unmanaged coniferous plantations with high SD laden with dead branches. We established two plots (P1 and P2) laden with dead branches under the same SD of 2250 stems ha−1 but with different numbers of dead branches (56 vs. 47 branches per tree) in an unmanaged Japanese coniferous plantation. Results demonstrated that a large difference was found in canopy storage capacity (S) in P1 and P2 (3.94 vs. 3.25 mm), which was influenced by the different number of dead branches; therefore, the IL ratio to gross rainfall differed considerably (32.7% in P1 and 26.7% in P2) regardless of the SD being the same. The difference in S enables the RGAM to reflect the influence of dead branch structures on IL, leading to an acceptable RGAM performance for both P1 and P2 (“fair” IL relative errors: −20.2% vs. −16.1%) in the present study of unmanaged coniferous plantations with high SD laden with dead branches.