Rainwater Retention Research Articles

Development of a web-based platform for rainwater retention facility design

ABSTRACT This study develops a web-based operational platform to streamline the integration of GIS technologies, hydrological analyses, and regulation inspections in the design process of rainwater retention facilities. The system incorporates a comprehensive design procedure, which entails: (1) selecting the type and size of the retention facility based on predefined options, (2) conducting hydrological analyses specific to the development site, and (3) verifying the design’s compliance with relevant regulations. Users can visualize flow hydrographs before and after development, estimate the increase in runoff volume resulting from development, and assess the reduction in peak outflow achieved by the retention facility. The system can also validate the adequacy of the retention facility design in alignment with regional flood control objectives. It offers a user-friendly geographical interface for designing retention facilities and drainageways at development sites. Furthermore, design information displayed on the platform can be conveniently shared with regulatory authorities through a web link.

Optimize Stormwater Management for Green Roofs Based on IoT Technology and Sensor Networks

The intensification of global climate change and the significant increase of extreme rainfall events have made traditional urban drainage systems face great adjustments. As a key component of green infrastructure to avoid urban flood risk, green roofs are receiving increasing attention due to their unique capabilities in stormwater management. This paper explores the potential of Internet of Things (IoT) technology and sensor networks to enhance green roof stormwater management. Integrated real-time monitoring of key environmental parameters, including soil moisture, temperature and rainfall, enables the system to dynamically adjust roof drainage and irrigation strategies. This greatly improves the rainwater retention capacity and reduces the pressure on the municipal sewage system. The results show that the combination of IoT technology and sensor networks not only improves the efficiency of green roof management in combating climate change, but also promotes the efficient use of water resources and enhances the adaptability and sustainability of the system. This research provides the necessary technical support for the wider adoption of green roofs in urban environments and offers viable solutions to future challenges posed by climate change.

The Example of the “Green Class” Project in Krakow: A New, Mobile System of Educational Facilities That Takes Rainwater Retention into Account

The Example of the “Green Class” Project in Krakow: A New, Mobile System of Educational Facilities That Takes Rainwater Retention into Account

Modelling the behaviour in socio-technical systems for policy assessment - A comparison of modelling approaches using the example of Sponge City concept implementation

How are policies affecting the social behaviour of actors and thus the dynamics of the corresponding socio-technical systems? This question is of central relevance to understand what policies might be effective for sustainable transitions and transformation where social changes are immanent. Exploratory modelling approaches such as agent-based modelling (ABM) are suitable and established to analyse how individual, especially heterogeneous behaviour emerges to affect social systems. In contrast to this micro-level perspective of understanding how social behaviour influences system behaviour, System Dynamics models (SDM) focus on the macro-level perspective by analysing how system interactions drive complex system behaviour. Qualitative modelling approaches such as Causal Loop Diagrams belonging to the Systems Thinking Modelling (STM) toolbox remain descriptive but need much less effort for model development. In this article, we compare how the different approaches ABM, SDM and STM can model social behaviour in socio-technical systems and what different kind of insights can be gained to assess the efficacy of policies. It discusses the advantages and limitations of the different approaches for their application in behavioural public policy modelling for sustainability transition. Therefore, three exemplary models (STM, SDM, ABM) are created for the same topic of implementation dynamics of adaptation measures to foster rainwater retention (Sponge City concept) in a multi-residential quarter. As a result, the risk of green gentrification is identified. Three hypothetical policies are implemented to illustrate the differences between the three modelling approaches for their use in policy assessment. Based on that, we discuss how the three modelling approaches conceptualise behaviour in general.

Waste-green infrastructure nexus: Green roof promotion by digestate and digestate biochar from food waste

Waste—Green Infrastructure Nexus is crucial to mitigate carbon emissions in waste disposal and promote eco-functions of green infrastructure in a circular bio-economy. Our purpose is to verify the feasibility of the nexus via “food waste anaerobic digestion — digestate/digestate biochar — green roof promotion”. The results found that food waste digestate and digestate biochar significantly promoted green roof plant growth, evapotranspiration, rainwater retention, runoff reduction, and prevention of nutrient leaching. Digestate treatments were better than digestate biochar for the green roof promotion. The promotion ranked consistently with 20 % digestate > 10 % digestate > 20 % digestate biochar > 10 % digestate biochar > control in stolon growth, leaf emergence, branching of Paspalum vaginatum, green roof establishment, rainwater retention, runoff reduction, and the leaching of nitrogen, phosphorus, potassium. This study demonstrated that food waste could be regenerated to promote urban green infrastructure to form a circular bio-economy by the Waste—Green Infrastructure Nexus.

Green Roofs: Nature-Based Solution or Forced Substitute for Biologically Active Areas? A Case Study of Lublin City, Poland

Green roofs have become an increasingly popular feature in building design, driven by their bio-physical properties and aesthetic and recreational values. They serve as a key element in promoting the integration of Nature-Based Solutions (NBSs) in urban fabrics, aiming to enhance urban environments, mitigate climate impact, and create more sustainable urban spaces. Polish regulations mandate that investors maintain a designated proportion of biologically active areas, ensuring natural vegetation and rainwater retention. Green roofs fulfill this requirement and can serve as compensation for the loss of biologically active areas due to construction. Unfortunately, the regulations lack specificity regarding their construction. This study aimed to examine whether green roofs consistently represent NBSs, as frequently presented in the scientific literature, or rather serve as a legal substitute for biologically active areas. The research was conducted in Lublin, the ninth largest city in Poland. Field studies, analysis of planning documentation, and review of administrative decisions have revealed that the majority of green roofs in Lublin have a greenwashing character, meaning they were installed to meet urbanistic indicators rather than for climate, environmental, or aesthetic reasons. Such studies have not been conducted before in relation to local spatial development plans and administrative decisions in Poland, and they show that this approach does not contribute to increasing biodiversity on investment plots. Notably, the investor would be denied construction permits without the incorporation of green roofs. Consequently, this leads to the conclusion that not all green roofs fulfill the criteria of NBS, as not all ensure an increase in biodiversity. Therefore, legal provisions regarding their establishment should be revised and specified.

«Green» structures in the urbanized environment: studying the impact of «green» roofs on environmental parameters and rainwater quality. Bibliographic review

A quantitative analysis of the most cited articles published in the Scopus scientometric database by 2023 is carried out. It is shown that most of the publications, the object of study of which are "green" structures, focus on the study of "green" roofs. It is shown that since 1981, the number of studies on green roofs has been steadily increasing: approximately 45% of articles focus on the benefits in terms of thermal impact and thermal insulation, 18% on rainwater drainage, 15% on air quality, 5% on the noise-absorbing properties of green roofs, and 17% on the costs of building and operating green roofs, recreational facilities, fire protection, and other related issues. The requirements and commonly used materials for a standard green roof are described, as well as the percentage of scientific publications, depending on the functions and layers of green roof construction involved. An analysis of the most cited scientific studies on the impact of green roof systems on wastewater quality was conducted. It is shown that the results of the studies presented in these publications indicate the need for further study of the impact of a "green" roof on the amount of pollution in the water flowing from its surface. It is emphasized that further research should focus on the structural layers of the roof (thickness and materials used), namely the thickness and types of substrate layers, as well as on the conditions of plant care (e.g., fertilization), especially on intensive green roofs. In addition, it should be studied and analyzed how the retention of rainwater by plants and the soil layer of a green roof affects the relative humidity of the air near the building during periods without rain. The most cited scientific studies on the reduction of air pollutants by means of green roofs are analyzed. It is concluded that future research should focus on the study of plant species that are well adapted to growing on roofs (in temperate climates) and most effectively carry out the process of photosynthesis, absorbing CO2 and releasing O2 into the atmosphere around the building. The article analyzes the most cited scientific publications on the noise-absorbing properties of green roofs. It is substantiated that it is necessary to maximize the percentage of green roofs implementation on all buildings and structures in the city so that green roofs can significantly affect the quality of the environment in urbanized areas.

Feasibility Assessment and Environmental Benefits of Developing Rainwater Retention Ponds Across Najran Valley

Feasibility Assessment and Environmental Benefits of Developing Rainwater Retention Ponds Across Najran Valley

The water flow diagram

IntroductionThe Water Flow Diagram (WFD) is a novel advocacy and communication tool that presents urban water supply and management in a simple visualization. Rapid urbanization, growing populations, and the climate crisis increase the pressure on water resources, particularly in urbanized areas. The WFD aims to foster a dialogue around conflict of interests and opportunities among different stakeholders, and trigger actions toward more sustainable urban water management (UWM), as well as a water secure future.MethodThe WFD is produced from data on water abstraction, water use of different sectors, water treatment, water recycling and contamination risks. The data were obtained from government services, wastewater and water utilities, large industries, universities and reports of intergovernmental organizations. If these sources did not have data, reports from NGOs or consultants, comparable contexts, default values or expert judgements were considered. The annual water flows are presented in a Sankey Diagram. An intuitive color code highlights the flows as “problematic” or “appropriate” and points to areas where UWM practices should be improved.Results and conclusionsThe final diagrams are a concise instrument that identifies challenges of UWM in the four application cases presented in this article. Key challenges that became evident included: pollution from agricultural production, the lack of wastewater and sanitation infrastructure, high water losses in the distribution networks, water exports leading to a lack in local supply and sewer overflows during heavy rainfalls. Opportunities identified were the need to: invest in sanitation and wastewater to protect resources, create coordination bodies to align conflict of interests, and/or invest in blue-green infrastructure for rainwater retention. The WFD triggered local actions, such as in-depth discussions between relevant actors, the formation of integrated water use committees and the interest of the national ministry in Senegal to replicate the diagram for other locations. This article presents the methodology, discusses the four case studies and deliberates on the prospective use of the WFD.

Peatmass Change and Water Level Influencing Regenerated Melaleuca Forest after a Fire in U Minh Thuong National Park, Vietnam

Following the largest forest fire in Vietnam in 2002, various activities were undertaken to sustain the mangrove forest on peat soil remnants in the Mekong Delta region. These activities included promoting natural regeneration, afforestation, and rapid forest restoration measures, in addition to other protective measures such as rainwater retention to maintain moisture levels for fire prevention. However, two critical challenges emerged: allowing the forest to naturally regenerate would lead to annual forest fires but maintaining a constant water level through year-round water retention would harm biodiversity. The study was conducted in U Minh Thuong National Park to address forest regeneration. After a major forest fire in Vietnam, various measures were taken to promote forest regeneration, including afforestation, silvicultural solutions, and hydrological techniques such as rainwater storage to maintain humidity and prevent future fires. A hand drill was used to collect samples, and a total of 15 plots were set up to survey the growth of the forest at three peat thickness levels. At each of the three collection sites, samples of one kg were collected and labeled according to the site as UTM1, UTM2, and UTM3. The samples were then sent to the laboratory of the Southern Institute of Forestry Science for analysis. There was a relationship between the chemical indicators of peat and the evolution of the Melaleuca forest. Peat thickness and flooding regime significantly influenced the growth of the Melaleuca forest, while another identified relationship was between peat chemical indicators and forest growth. The chemical composition of peat water changed significantly due to the rainy and dry seasons, with nutrient content and pH affecting forest growth. Peat thickness and flooding regime were essential in regulating forest growth. These studies highlight the importance of considering multiple factors, such as peat thickness and chemical properties, when developing effective forest restoration strategies. By understanding the relationship between peat thickness, chemical properties, and forest growth, forest managers can develop targeted strategies to promote regeneration while minimizing negative impacts on biodiversity.

Sub-Shrub Components Change the Soil Water Storage Response to Daily Precipitation and Air Temperature in the Loess Plateau

Soil water shortage has become a severe issue in ecological restoration and sustainable development in the Loess Plateau, facing the challenges of climate change and vegetation restoration. This study monitored the soil water content in surface soil (0–40 cm) with different sub-shrub component treatments, including the natural condition (NC), the canopy plus the roots (CR) and only the roots (OR), to analyze the change in soil water storage (∆W) and its response to precipitation (P) and air temperature (Ta) on a daily scale. P was the main factor controlling the daily ∆W, contributing 49–52% to the variation in the daily ∆W, and Ta only explained 6–21% of the variation. Minimum P amounts of 0.74–1.12 mm and maximum Ta of 29.09–32.00 °C were the thresholds required to increase soil water storage (W). Sub-shrub components showed significant influences on soil water conservation. We found that the ∆W hierarchy for each sub-shrub treatment was NC (1.73 mm) > CR (0.71 mm) > OR (0.56 mm) on rainy days and NC (−0.53 mm) < CR (−0.36 mm) < OR (−0.06 mm) on no-rain days. Additionally, the hierarchy of the rainwater retention rate was NC (26.43%) > OR (13.71%) > CR (4.58%). Thus, a canopy could increase infiltration and hugely consume soil water at the same time, while litter could weaken or offset the canopy’s effects and the roots promote infiltration with little evaporation loss.

Quantitative, Qualitative and Thermal Aspects of Rainwater Retention on Wetland Roofs

Wetland roofs (WRs) are a multi-functional green infrastructure measure to mitigate the negative effects of climate change. The present work advances knowledge in the field of WRs by analyzing the performance of rainwater management, focused on water sufficiency, water quality and cooling potential. Automatic monitoring, covering weather conditions, temperature and the conductivity of WR water, and the amount of outflow into retention tanks, was supported with automated sampling of water for laboratory analysis of BOD5, phosphate phosphorus, suspended solids, electrical conductivity (EC), redox potential (Eh), color and pH. From April to September 2022, a precipitation deficit of 395.45 mm and a negative climatic water balance of 267.91 mm were observed. It was necessary to fill up the system several times in order to maintain water at the assumed level. In most cases, the values of EC observed during the monitoring period were higher than those reported for rainwater. Continuous monitoring of EC in the wetland was a useful tool for the observation of operating activities in the system; however, it was not sufficient for system control. BOD5 values did not exceed 6 mg dm−3 and were lower than reported for urban rainwater retention reservoirs. Suspended solids values did not exceed 27 mg dm−3. Color varied between 0 and 101 PtCo, with the highest values noted in July and the beginning of August. The pH value ranged between 7.28 and 8.24. The Eh varied between 155 and 306 mV, with lower values associated with the filling up of the wetland. Peak values of PO4-P were observed between the end of July and the beginning of September 2022, with a maximum concentration of 232 µg dm−3 utilized by the wetland within one month. Monitoring of the water and air temperature showed a thermal buffering effect of the wetland. The results of the research, conducted during the growing season, allow for better management of rainwater on the roof. However, there is a need to expand the scope of the analyzed water quality parameters. Although there are several limitations to the analysis, the present study partially fills the existing knowledge gap and may generate further interest in this topic among researchers and decision-makers.

Load bearing capacity analysis of concrete sidewalk system designed to ensure comfort of walking for people with a motor disability

The paper looks at a novel structural solution to sidewalks. The proposed system consists of a box element as a substructure and a concrete slab with openings for rainwater infiltration. Such a design will make the sidewalk comfortable for pedestrians with motor impairments, friendly for urban tree root systems and durable. The article provides stress and strain calculations for the variants of the new design. We used the finite element method for the analysis. The results confirm that the proposed variants meet the assumed strength criteria and can therefore be used in the next research steps, that is, permeability tests, rain-water retention simulations, laboratory testing. Highlights Concrete paving slab with environmental approach. Concrete paving slab for people with motor disabilities. The first study implementing FEM method supported by the Barcelona model to analyse stresses and strains in sidewalk pavement.

Application of Perennial Sweet Pea in Soil and Water Conservation

To address the issue of soil erosion and limited economically valuable vegetation resources, perennial sweet peas were introduced to Hebei Province, China, and showed favorable biological attributes. Nevertheless, its specific efficacy within soil and water conservation endeavors requires further examination. This study selected four trial sites within Hebei Province to assess four-year-old perennial sweet peas’ soil and water conservation functionality. The findings underscored that cultivating perennial sweet pea plots on 9° disturbed slopes notably outperformed bare ground (CK) in their rainwater absorption capacity. Specifically, in the 0–20 cm soil layer, moisture increased from 10.51% to 17.39%, in the 20–40 cm layer from 10.63% to 17.25%, and in the 40–60 cm layer from 10.09% to 16.04%. The dense canopy formed by perennial sweet peas effectively intercepted 25–32% of precipitation. Fallen organic matter also demonstrated commendable water absorption features. During severe rain, the perennial sweet pea showcased a 90.4% runoff reduction and a notable sediment interception. Their deep and well-developed root system enhanced soil structure and infiltration. The outcomes of this study highlight the perennial sweet peas’ potential in soil erosion mitigation, rainwater retention, and soil improvement, which carries substantial implications for sustainable land management and ecosystem restoration initiatives. Furthermore, the successful introduction of perennial sweet peas could serve as a model for analogous ecological interventions in regions confronting similar challenges, offering holistic solutions to soil and water conservation in environmentally sensitive areas.

Influence of urban land use types on ecosystem services in two rapidly urbanizing cities of southwestern Nigeria.

Many ecological functions in cities are based on urban soils. In order to meet the needs of the expanding human population and the ensuing strain on natural resources, it is essential for soil-based ecosystems to function. Approximately 80% of the total urban land use in Akure and Okitipupa, Nigeria, are used for commercial, residential, and agricultural purposes. Thus, we investigated the potential of these three urban land use types (ULUTs) to offer a variety of ecosystem services in the two different cities. Soil properties that serve as proxy indicators for four ecosystem services were measured in the ULUTs: hydraulic conductivity (Kunsat) and available soil water for rainwater retention; soil organic carbon (SOC) stock for carbon storage; soil microbial respiration (SMR) for the capacity to support biological activity; and soil compaction (PR) and total nitrogen (TN) for promoting plant growth. The location and ULUT resulted in distinct ecosystem service provisioning. In comparison to Akure, Okitipupa soils had lower PR (1.0 vs 1.1MPa) but higher Kunsat (36.9 vs 10.3cmh-1), SOC stock (6.9 vs 5.7Mg C ha-1), and SMR levels (35.2 vs 23.6mg CO2-C g-1 soil). Commercial soils exhibited more compaction than residential and agricultural soils but less SOC stock and Kunsat, and TN in both locations. The properties of the urban soils showed that the soils could support a variety of ecosystem services. Different soil properties at the city level led to variations in the potential for ecosystem services in various locations, and these variations were observable in commercial, residential, and agricultural soils. Understanding urban soils would thus necessitate both cross-city comparative studies as well as within-city examinations of the potential for ecosystem services for various urban land use types.

ASSESSMENT OF THE RISK OF FLOODING IN AN URBANIZED AREA IN RESPONSE TO HEAVY RAINS: CASE STUDY OF THE WARSAW CHOPIN AIRPORT

The paper presents the adaptation of the hydrodynamic Storm Water Management Model(SWMM) for the subcatchment area of the Służewiecki Stream in Warsaw, the major part of whichis the area of the Chopin Airport. The SWMM model was used for calculating the water outflowfrom the studied urbanized area in response to rainfall with the probabilities of 20 and 10%, andthen to assess the possibility of flooding as a result of rainwater spillage from the Airport drainagesystem. The scope of the work also comprised assessing the impact of the existing retention tanksat the Airport on the reduction of maximum flows in the Służewiecki Stream channel. Simulationsin response to the rainfall event with a probability of 10% have shown that there are locations(sewer manholes) within the airport area where short-term rainwater overflows may potentiallyoccur. Retention of rainwater in tanks and flow control through gate valves have a significantimpact on a reduction of flows in the Słuzewiecki Stream, thus reducing the risk of flooding in thestudied catchment area.

Stormwater Tree Pits for Decentralized Retention of Heavy Rainfall

Stormwater tree pits with storage elements enable the irrigation of urban trees and can potentially act as decentralized rainwater retention basins. This paper mainly focuses on analyzing this potential. Field tests were conducted to investigate the irrigation behavior and the storage effect of a storm water tree pit system using Perl hoses as irrigation elements over a period of two years. The rainfall, storage volumes, and soil moisture within the employed planting pit were measured. With the help of system modeling, the retention ability of the storm water tree pit system was analyzed. The available storage volume was sufficient to irrigate trees for several days. During the measurement period, about 15% of the inflowing rainwater was fed to the root zone of the tree. With practical storage volumes of 200 to 300 m3/ha, a remarkable amount of water from heavy rainfall could be completely stored, thus significantly reducing the risk of flooding. The retention effect and irrigation behavior largely depend on the soil conditions and the technical possibilities of the equipment supplying the root area (in this case, Perl hoses). Further investigations are required to determine the influence on the growth conditions of trees and optimize of the system for discharge into the root zone.

Rainwater Retention Test of Various Green Roofs: Influence on Membrane Temperatures and Evapotranspiration

Green structures such as roofs or facades are great examples of ways to mitigate climate change, and they have multidisciplinary benefits. One of them is water retention during storms and high rainfalls. In this paper, the impact on the temperature of a membrane after excessive watering was investigated. The results of watered samples were compared to the non-watered ones. This test was carried out on five equal samples. The results showed that the actual foliage cover is very important. The worst results were obtained by the samples that did not have sufficient plant (foliage) cover. Notable differences in courses after watering reached up to 7 °C and lasted up to five days. Visible differences after watering were also exhibited by other samples. The type of drainage/retention layer also influenced the results, whereas the hard-profiled plastic board had high practical retention, which impacted temperatures over a long time period. The actual water content influenced and reduced the daily amplitude from 13 to 7 °C for at least five sunny days. This confirms the theoretical evapotranspiration calculations and actual water content in green roofs. In this case, the water content in the samples proves the cooling effect on the waterproofing membrane.

Functional urban ground-cover plants: identifying traits that promote rainwater retention and dissipation

Urban vegetation can influence urban hydrology and reduce the risk of flooding. Urban forestry studies have suggested that tree type and species choice affect the amount of rainwater intercepted and retained. Little information exists, however, for other landscape typologies, and the sorts of ground-cover plants that are best used to retain/detain rainwater during storm events. This is important as many urban spaces are too small to facilitate trees, but can accommodate roadside vegetation, buffer strips, rain gardens, green roofs and stormwater planters. Thus, this research aimed to determine how choice of ground-cover taxa affected rainwater interception and retention. Six model species with contrasting leaf morphologies were used to determine how well rainwater was intercepted, but also dissipated through evapotranspiration (ET). A pot-based system was used to determine how plant water balance changed during late summer in the UK, with the aim to understand how leaf traits affected hydrological processes. Plant choice was important, with fine-leaved taxa, Festuca glauca and Dianthus ‘Haytor White’ showing best rainwater interception and Festuca demonstrating highest rates of dissipation from the substrate. Overall, compared to non-planted pots, those with plants present were more effective at capturing water (by 2.3–3.0x), and evapo-transpiring water (by 2.5-4.0x). Results indicate that ground cover vegetation has potential to aid urban water management in those localities where space is limited for trees. Plant choice and community-structure should be considered, especially when there is a desire to dry out soil/substrate quickly and restore maximum soil moisture holding capacity.

Green Roofs as an Urban NbS Strategy for Rainwater Retention: Influencing Factors—A Review

There has been a rapid development in studies of nature-based solutions (NbS) worldwide, which reveals the potential of this type of solution and the high level of interest in its implementation to improve the resilience of cities. Much relevant information and many important results are being published, and it is now possible to see their diverse benefits and complexity. Several authors highlight their role in urban areas not just in temperature control, but also in human health, ecosystem development and water management. However, in the current reality of cities, where water use is being (and will be) constantly challenged, analyzing NbS advantages for the urban water cycle is crucial. This study performed an intense review of the NbS literature from 2000 to 2021, to identify their contributions to the improvement of urban water cycle management and thus provide a solid information base for distinct entities (public institutions, private investors and the urban population in general) to disseminate, apply and justify their implementation. In general terms, the urban water cycle embraces not only the abstraction of water for urban consumption, but also its return to nature and all the stages in between, including water reuse and stormwater management. This review will highlight the important benefits that NbS in general, and green roofs in particular, provide to urban stormwater control, a key factor that contributes to urban sustainability and resilience in order to face future climate challenges. The novelty of the present review paper falls within the conclusions regarding the crucial role that NbS develop in urban water management and the main features that must be tested and technically enhanced to improve their functioning.