Infiltration Trenches Research Articles

Investigating Tradeoffs of Green to Grey Stormwater Infrastructure Using a Planning-Level Decision Support Tool

Integrated decision support tools are needed to investigate the tradeoffs of stormwater control measures (SCMs) and determine the optimal suite of SCMs based on the needs of watersheds. In this study, an urbanized watershed undergoing infill development (the Berkeley neighborhood located in Denver, CO, USA) was modeled using a modified version of the U.S. Environmental Protection Agency’s (EPA) System for Urban Stormwater Treatment and Analysis IntegratioN (SUSTAIN). The primary goal was to compare the relative performance between green and grey SCMs, use optimizations and a planning-level approach to assist in decision-making, and discuss how stakeholder and community preferences can shift which SCMs are optimal for the watershed. Green and grey SCMs have variable hydrologic performance based on design and function, and both offer benefits that may be important to decision makers. Our results showed that infiltration trenches and underground infiltration were optimal for reducing flow volumes while vegetated swales and underground detention were optimal for pollutant concentration reduction. Stakeholders value both of these benefits and so the optimal stormwater solution in the Berkeley neighborhood included a mix of green and grey SCMs. Determining the optimal SCMs while considering tradeoffs in costs and associated benefits was complex and multifaceted. Modeling results such as those presented here are critical for informing stakeholders’ decision-making process.

Selection of best stormwater management alternative based on storm control measures (SCM) efficiency indices

Abstract Overcoming conventional stormwater management problems and finding appropriate control methods for safely discharging excess runoff from impervious areas is an essential part of any sustainable urban planning. This study aims to analyze the performance of different storm control measures (SCMs) applied to Vellore Institute of Technology (VIT) campus situated in Vellore, Tamil Nadu, which is a highly urbanized catchment. Different SCMs were designed for the VIT campus based on low impact development (LID) options available in stormwater management model (SWMM) software. The most suitable SCM was selected based on its ability to match pre-urbanized hydrographs as close as possible. The SCM location was identified by a localized survey, in such a way that there is least disturbance to the existing storm sewer network. The percentage reduction of peak flow under each proposed SCM were obtained as follows: bio-retention (19.8%), rain garden (18.69%), green roof (49.17%), infiltration trench (20.02%), permeable pavement (22.6%), rain barrel (12.95%), rooftop-disconnection (10.79%) and vegetative swales (17.23%). The results indicated that Option 9 (combination of permeable pavement and bioretention) and Option 10 (permeable pavement and infiltration trench) were better at reducing peak runoff and increasing infiltration. The peak runoff reduction for Options 9 and 10 were observed to be 32.05 and 39.81%, whereas the percentage increase in infiltration was observed to be 25.7 and 29.45% respectively.

Dynamic water balance of infiltration-based stormwater best management practices

Infiltration-based urban stormwater best management practices (BMPs) are widely used for the reduction of runoff volumes and improvement of runoff quality. In this paper, closed-form analytical equations, collectively referred to as the analytical stormwater models (ASMs), are derived for analyzing the dynamic water balance of infiltration-based BMPs. For simplicity, previously developed ASMs only considered vertical infiltrations through the bottoms of infiltration-based BMPs although lateral infiltrations are not negligible and can even be the predominant ones in some real cases. To overcome this limitation, the ASMs developed in this study take into account infiltrations through the sides and the bottoms of BMPs. The concept of effective storage capacity is also proposed and used in this study to reduce the discrepancies caused by representing rainfall inputs as instantaneous pulses. Using infiltration trench as an example, the acceptability of the simplifying assumptions based on which the ASMs are derived is demonstrated by comparing ASMs’ results with those from numerical simulations which do not require the same simplifying assumptions. The effects of many influencing factors on the hydrologic performance of infiltrations trenches are also illustrated. The ASMs are recommended as a computationally efficient alternative for use in the planning, design, and analysis of infiltration-based BMPs.

Characterizing a novel in-situ oxygen delivery device for establishing controlled redox zonation within a high infiltration rate sequential biofilter

By applying favorable oxic and oligotrophic conditions through subsequent aeration and an additional infiltration step, the sequential managed aquifer recharge technology (SMART) was proven to better remove trace organic chemicals (TOrCs) than conventional MAR systems. To minimize the physical footprint, pumping costs and hydraulic retention times, as well as to overcome limitations of site-specific heterogeneities of such systems, the SMART concept was further upgraded by two main engineered technologies. This SMARTplus bioreactor is comprised of an infiltration trench and highly homogenous porous media to provide high infiltration rates and plug-flow conditions. Additionally, an in-situ oxygen delivery device, in particular a self-designed PDMS gas-liquid membrane contactor, was designed to establish favorable subsurface oxic conditions. This novel SMARTplus technology was investigated at pilot scale and is designed for advanced water treatment either in the context of water reuse or treatment of impaired surface water. To determine the design specifications and to construct a pilot-scale membrane contactor, the mass transfer coefficients of the PDMS membrane were investigated at lab-scale for varying Reynold numbers (0.2–2). With the help of the customized membrane contactor, homogenous, bubble-free and passive oxygen delivery could be successfully demonstrated at pilot-scale under laminar flow conditions and short contact times. Oxygen concentrations downstream of the membrane contactors met the design specifications (>1 mg/L) as long as the required feed water quality was provided. However, high NH4+ concentrations in the secondary effluent resulted in higher and unsteady oxygen demand than the target oxygen transfer rates could meet and suboxic conditions prevailed. Although a 20–50% enhancement in the removal of certain compounds (4-FAA, antipyrine, sulfamethoxazole, and citalopram) was achieved, demonstration of the full potential of enhanced TOrC removal by SMARTplus was hindered due to unsteady feed water quality.

A Conceptual Design Model to Groundwater Recharge in Dense Urban Area Roads

As increasing of Urbanization, the soil surface which is permeable through which groundwater recharge by infiltration can occur is reducing, this is resulting in much less groundwater recharge and greatly increased surface runoff. This Paper deals with the increasing of groundwater table utilizing of road runoff or stormwater through artificial recharge techniques. Infiltration devices that redirect surface runoff to the subsurface environment should be adopted, the infiltration system like infiltration trenches can be used to increase the groundwater table and the use of infiltration trenches has proven to be useful to reduce runoff in urban surface. By making continuous infiltration trenches in an area below the footpath and providing a filter media in it which consists of different layers of gravel and sand. Due to which filtered water goes inside the earth's surface and infiltration increases and the maximum portion of surface runoff go inside subsurface and stormwater management can be managed by using this technique. The methodology, applications, design & calculations are presented and discussed.

Effects of Infiltration Trenches and Bio-Retention Ponds on Stormwater Runoff in Eldoret Town

Effects of Infiltration Trenches and Bio-Retention Ponds on Stormwater Runoff in Eldoret Town

Green Infrastructures for Urban Water System: Balance between Cities and Nature

Urban water systems face severe challenges such as urbanisation, population growth and climate change. Traditional technical solutions, i.e., pipe-based, grey infrastructure, have a single purpose and are proven to be unsustainable compared to multi-purpose nature-based solutions. Green Infrastructure encompasses on-site stormwater management practices, which, in contrast to the centralised grey infrastructure, are often decentralised. Technologies such as green roofs, walls, trees, infiltration trenches, wetlands, rainwater harvesting and permeable pavements exhibit multi-functionality. They are capable of reducing stormwater runoff, retaining stormwater in the landscape, preserving the natural water balance, enhancing local climate resilience and also delivering ecological, social and community services. Creating multi-functional, multiple-benefit systems, however, also warrants multidisciplinary approaches involving landscape architects, urban planners, engineers and more to successfully create a balance between cities and nature. This Special Issue aims to bridge this multidisciplinary research gap by collecting recent challenges and opportunities from on-site systems up to the watershed scale.

Developing a novel biofiltration treatment system by coupling high-rate infiltration trench technology with a plug-flow porous-media bioreactor

The sequence of two infiltration steps combined with an intermediate aeration named ‘sequential managed aquifer recharge technology (SMART)’ proved to be a promising approach to replenish groundwater using treated wastewater effluents or impaired surface waters due to efficient inactivation of pathogens and improved removal of many trace organic chemicals. To minimize the physical footprint of such systems and overcome limitations through site-specific heterogeneity at conventional MAR sites, an engineered approach was taken to further advance the SMART concept. This study investigated the establishment of plug-flow conditions in a pilot scale subsurface bioreactor by providing highly controlled hydraulic conditions. Such a system, with a substantially reduced physical footprint in comparison to conventional MAR systems, could be applied independent of local hydrogeological conditions. The desired redox conditions in the bioreactor are achieved by in-situ oxygen delivery, to maintain the homogenous flow conditions and eliminate typical pumping costs. For the time being, this study investigated hydraulic conditions and the initial performance regarding the removal of chemical constituents during baseline operation of the SMARTplus bioreactor. The fit of the observed and simulated breakthrough curves from the pulse injection tracer test indicated successful establishment of plug-flow conditions throughout the bioreactor. The performance data obtained during baseline operation confirmed similar trace organic chemical biotransformation as previously observed in lab- and field-scale MAR systems during travel times of <13 h.

Testing of the Storm Water Management Model Low Impact Development Modules.

Stormwater infrastructure designers and operators rely heavily on the United States Environmental Protection Agency's Storm Water Management Model (SWMM) to simulate stormwater and wastewater infrastructure performance. Since its inception in the late 1970s, improvements and extensions have been tested and evaluated rigorously to verify the accuracy of the model. As a continuation of this progress, the main objective of this study was to quantify how accurately SWMM simulates the hydrologic activity of low impact development (LID) storm control measures. Model performance was evaluated by quantitatively comparing empirical data to model results using a multievent, multiobjective calibration method. The calibration methodology utilized the PEST software, a Parameter ESTimation tool, to determine unmeasured hydrologic parameters for SWMM's LID modules. The calibrated LID modules' Nash-Sutcliffe efficiencies averaged 0.81; average percent bias (PBIAS) -9%; average ratio of root mean square error to standard deviation of measured values 0.485; average index of agreement 0.94; and the average volume error, simulated vs. observed, was +9%. SWMM accurately predicted the timing of peak flows, but usually underestimated their magnitudes by 10%. The average volume reduction, measured outflow volume divided by inflow volume, was 48%. We had more difficulty in calibrating one study, an infiltration trench, which identified a significant limitation of the current version of the SWMM LID module; it cannot simulate lateral exfiltration of water out of the storage layers of a LID storm control measure. This limitation is especially severe for a deep LIDs, such as infiltration trenches. Nevertheless, SWMM satisfactorily simulated the hydrologic performance of eight of the nine LID practices.

Optimum numbering and sizing of infiltration-based water sensitive urban design technologies in South Australia

ABSTRACT The existing drainage systems consider storm water as a waste product and its main focus is on collecting the runoff from urban catchments as quickly as possible and discharging it into the nearby outlets. These traditional drainage systems cannot consider important utilisation of storm water. Therefore, a decentralised storm water management option, known as, Water Sensitive Urban Design (WSUD) technologies, can be implemented in the urban catchments to minimise the negative hydrological impacts due to urbanisation. Hydraulic designs of three different types of infiltration-based WSUD technologies (leaky wells, soakaways and infiltration trenches) were designed for South Australian contexts. Modelling equations to estimate optimum numbering of infiltration systems were developed using SPSS and six different independent variables, such as soil hydraulic conductivity, size of the device, average recurrence interval of rainfall events, critical storm duration, rainfall intensity and roof size, were considered. The developed modelling equations were statistically significant and were applied in the real-case scenarios of South Australian catchments.

Transpiration by established trees could increase the efficiency of stormwater control measures

Evapotranspiration is an important aspect of the hydrological cycle in natural landscapes. In cities, evapotranspiration is typically limited by reduced vegetation and extensive impervious surfaces. Stormwater control measures (SCMs) seek, among other objectives, to move the urban hydrological cycle towards pre-development conditions, promoting processes such as infiltration and evapotranspiration. Yet, evapotranspiration is generally assumed to play a minor role in the water balance of stormwater control measures. Since established urban trees can use large quantities of water, their inclusion with stormwater control measures could potentially substantially increase evapotranspiration. We installed infiltration trenches alongside established Lophostemon confertus trees in the grassed verges of a typical suburban street to assess 1) whether redirecting stormwater to trees could increase their transpiration and 2) the contribution of transpiration to the water balance of stormwater control measures. We measured stormwater retention and transpiration for two spring-summer periods and estimated an annual water balance for the infiltration trenches. Although redirecting stormwater to trees did not increase their transpiration, these trees did use large volumes of water (up to 96 L d−1), corresponding to 3.4 mm d−1 per projected canopy area. Annually, stormwater retention was 24% of runoff and tree transpiration was equivalent to 17% of runoff. Our results suggest that streetscapes fitted with tree-based stormwater control measures, could increase the volumetric reduction of stormwater runoff by increasing the proportion of evapotranspiration in the water balance. Since public space is highly contested in cities and increasing canopy cover is a priority for many planners, integrating trees with stormwater control measures could provide dual benefits for a single management intervention, enabling a greater number of distributed stormwater control measures with smaller impervious catchments in the streetscape.

Restoration of grazing land to increase biomass production and improve soil properties in the Blue Nile basin: effects of infiltration trenches and Chloris Gayana reseeding

AbstractDegradation of crop and grazing lands is a pervasive problem that negatively impacts agricultural productivity and livelihoods of crop-livestock farmers in the Blue Nile basin of Ethiopia. Area enclosure together with a cut and carry livestock feeding system is often advocated as an approach for the regeneration of degraded grazing lands. This paper reports the results of a two-year farmer participatory study conducted to assess the effects of infiltration trenches (ITs) and Chloris gayana Kunth (Rhodes grass; cultivar Masaba; tetraploid; C4 grass species) reseeding on restoration of degraded grazing lands. A split plot design was used with IT as the main plot and C. gayana reseeding as a sub-plot on 28 private grazing plots under enclosure. The results showed that IT alone increased soil moisture content and prolonged the growing period. IT and C. gayana reseeding together significantly (P ≤ 0.05) increased herbage dry matter yield and improved soil chemical properties. The highest mean herbage dry matter yield (21 Mg ha−1 per cut) was recorded for plots treated with IT and reseeded with C. gayana. The higher herbage dry matter yield was attributed to increased soil moisture and the resultant prolonged growing period induced by the trenches coupled with the ability of C. gayana to effectively utilize the retained water. The results suggest that an integrated land management approach involving enclosure, in-situ water conservation and C. gayana reseeding can rapidly increase biomass productivity on degraded grazing lands while also enhancing soil quality with concomitant livelihood benefits for farmers.

Cost-Effective Optimization of Nature-Based Solutions for Reducing Urban Floods Considering Limited Space Availability

The conventional urban stormwater management practices focus on carrying away runoff quickly by lined conveyors, which increase the surface runoff and reduce the time of concentration, subsequently causing floods in downstream areas. Ecological Management Practices (EMPs) provide nature-based solutions for reducing flood risks in a sustainable and economically viable manner. However, in the rapidly urbanizing setups in developing nations, the application of EMPs is limited due to space availability, data scarcity and limited funding. This study uses a Non-Linear Programming Optimization Technique to provide modelling solutions in optimizing the land-use and costs under EMPs to reduce flood risks in the Quebrada Aries watershed in the Municipality of Heredia in Costa Rica. Depending on the availability and ease of execution, a combination of three EMPs (bio-retention areas, infiltration trenches and green roofs) were tested. The effect of the application of derived optimal combinations has been analysed. The optimal combination of EMPs analysed for different channel capacity was able to reduce the peak discharge for the worst flood causing event of 50 years return period from 16.86 m3/s (under current land-use) to 9 m3/s, 9.51 m3/s, 8.38 m3/s and 9.13 m3/s in four hypothetical scenarios considered. In urbanized catchments, EMPs cannot be applied indefinitely to avoid floods. However, an optimal combination of EMPs can drastically reduce the requirement of large capacity drainage channels. This information can help policy-makers to analyse trade-offs between urban development and flood control measures. The study is suitable for other data-scarce regions as well.

Seasonal drivers of chemical and hydrological patterns in roadside infiltration-based green infrastructure

Infiltration-based green infrastructure has become a popular means of reducing stormwater hazards in urban areas. However, the long-term effects of green infrastructure on the geochemistry of roadside environments are poorly defined, particularly given the considerable roadside legacy metal contamination from historic industrial activity and vehicle emissions (e.g., Pb). Most current research on green infrastructure geochemistry is restricted to time periods of less than a year or limited sets of chemical species. This further limits our understanding of systems that evolve over time and are subject to seasonal variability. Between 2016 and 2018, two infiltration trenches in Pittsburgh, PA, were monitored to determine infiltration rates and dissolved nutrient and metal content. The trench water was analyzed to characterize seasonal patterns in both trench function and chemistry. Shifting patterns in infiltration rate and geochemical activity show trends corresponding with seasonal changes. Trench function is dependent on the local water table, with the highest infiltration rates occurring when evapotranspiration is active and groundwater elevation is low. Two seasonal chemical patterns were identified. The first is driven by road salt application in the winter and interaction of the salt pulse increase Pb and Cu concentrations. The second is driven by the formation of summer reducing environments that increase dissolved Fe and Mn. These findings suggest that chemical and hydrological activity in infiltration-based green infrastructure varies seasonally and may remobilize legacy contamination.

Measuring performance of low impact development practices for the surface runoff management

Continuous urbanization over the last few years has led to the increase in impervious surfaces and stormwater runoff. Low Impact Development (LID) is currently receiving increased attention as a promising strategy for surface runoff management. To analyze the performance of LID practices for surface runoff management, a long-term hydrological modeling from 2001 to 2015 along with a cost-effectiveness analysis were carried out on a campus in Dresden, Germany. Seven LID practices and six precipitation scenarios were designed and simulated in a Storm Water Management Model (SWMM). A cost-effectiveness analysis was conducted by calculating the life-cycle costs and runoff removal rate of LID practices. Results demonstrated that the LID practices significantly contributed to surface runoff mitigation in the study area. The LID performance was primarily affected by the length of the precipitation scenarios and LID implementing schemes. The runoff removal rate of the LID practices fluctuated significantly when the rainfall scenario was shorter than 12 months. When the rainfall scenario exceeded 1 year the effects on the runoff removal rate was constant. The combination of an infiltration trench, permeable pavement, and rain barrel (IT ​+ ​PP ​+ ​RB), was the best runoff control capacity with a removal rate ranging from 23.2% to 27.4%. Whereas, the rain barrel was the most cost-effective LID option with a cost-effectiveness (C/E) ratio ranged from 0.34 to 0.41. The modeling method was improved in this study by conducting long-term hydrological simulations with different durations rather than short-term simulations with single storms. In general, the methods and results of this study provided additional improvements and guidance for decision-making process regarding the implementation of appropriate LID practices.

Influence of land use and land cover’s change on the hydrological regime at a Brazilian southeast urbanized watershed

Land use and land cover have a direct influence on the hydrological regime. Urbanization and deforestation are accountable for reducing the water infiltration and consequent runoff’s increase. These modifications lead to high peak flows responsible for catastrophic events. Thus, this work analyzed the impact of land use and land cover’s change on the hydrological regime in a Brazilian southeastern urbanized watershed; considering current and future scenarios. The hydrological model HEC–HMS was used to estimate stream flow and aided in the search for suitable solutions. Using the Land Change Modeler tool made possible to design 2030’s land use and land cover in Grande river watershed. Hydrological simulations were carried out for 2030 using HEC–HMS. Some of the forested areas were replaced by agriculture and pasture. The agricultural areas were the ones that showed greater expansion. Such changes contributed to a mean increase of 52% in the stream flow hydrograph when compared to the watershed’s current scenario. After the use of best management practices, the stream flow hydrograph had a mean reduction of 44%. The structures considered were bio-retention cells, rain gardens, infiltration trenches, and permeable pavements for urban areas. For rural areas, the practices suggested were level terraces, no-till farming, and contour farming. All structures were applied in a distributed manner throughout the watershed. Therefore, it is concluded that land use and land cover’s change in Grande river watershed significantly influence the stream flow regime, and the use of best management practices proved efficient in reducing floods.

Evaluating the effect of urban flooding reduction strategies in response to design rainfall and low impact development

Abstract Rapid urbanisation and climate change-induced watershed hydrologic alteration have increased urban flooding risks. As a strategy for urban flood control, low impact development (LID) practices focus on promoting the infiltration and detention of stormwater runoff. A modelling-based study was conducted to analyse LID performance in urban flooding reduction. Two-dimensional simulations were conducted to visualise the flood risk under different precipitation scenarios and LID schemes. An integrated evaluation system based on life-cycle cost analysis, the analytic hierarchy process, and regret decision theory were applied to assess the LID performance in multiple aspects. The results indicated that the LID practices achieved runoff control and flood mitigation to some extent, especially under mild rainfall events. According to the integrated evaluation, urban flooding risk could be sufficiently reduced with the LID combination of bioretention, infiltration trenches, and rain barrels in the given area.

Sistema de drenagem complementar com estudo comparativo de métodos para a Avenida Santos Dumont, Criciuma, SC – Estudo de caso

A urbanização das cidades intensifica a impermeabilização do solo, causando impactos negativos aos sistemas de drenagem, e assim gerando problemas de inundações que reduzem a qualidade de vida dos habitantes do município. O presente trabalho tem por objetivo propor um sistema de drenagem complementar para um trecho da Avenida Santos Dumont, localizada no município de Criciúma, Santa Catarina. O estudo foi realizado através do estudo de 4 modelos, um modelo com as observações reais da Avenida e três modelos criados para o estudo da drenagem complementar. Assim, o modelo A consiste na situação real da Avenida, o modelo B a adoção de alteração do revestimento superficial da área simultaneamente a coleta e uso das águas pluviais precipitadas sobre os telhados, o modelo C a implantação de trincheiras de infiltração e o modelo D a aplicação conjunta das ações implantadas nos dois modelos anteriores. Como resultados foram obtidos a redução das vazões lançadas no sistema de drenagem e, consequentemente, a redução dos problemas apresentados no modelo A. Foi concluído que o modelo D é o mais indicado para que sejam solucionados os problemas na Avenida atendendo as necessidades do município e dos habitantes locais.

Design of Sustainable Road Drainage System Model

The existing drainage system of roads proposed to manage the quantity of runoff from the road only, while the quality remains uncontrolled. In fact the pollutants and waste originated from the road surface contains hazardous substances. Sustainable drainage system (SUDS) concept offers various structures to solve both quantity and quality problems of surface runoff from roads. One of the potential drainage structure is filter drain or infiltration trench develope along the right side and left side of road. It could be developed by retrofitting the existing drainage channel of the road. The objective of this paper proposes the design model of road drainage based on the concept of a sustainable urban drainage system. The model consists of U-ditch channel, reservoir, an infiltration well. The bottom of U-ditch channel completed with a number of holes to make it porous. The channel filled with aggregate to filter the runoff from the road before flow down into the reservoir beneath. The water is then discharged to infiltration well. The model was developed based on rainfall data and other physical characteristics in Ambarawa City, Semarang Regency, Central Java.The channel dimensions and the depth of aggregate filter were designed base on runoff volume. The relationship among rainfall, runoff volume, area ratio, and drainage dimension are obtained. The results concept of sustainable road drainage is obtained in addressing the quality and quantity of rainwater.

Contributions to reduce the flood problems in critical points of the micro drainage system in the city of Carazinho

With the emergence of excessive flooding in the urban environment, the need for unconventional drainage control measures within the limitations of conventional solutions becomes evident. In the present study, infiltration trenches and reservoirs that collect and reserve rainwater were designed as control devices, attenuating the socio-environmental impacts caused by waterproofing of urban areas in the hydrological cycle and in the behavior of the hydrographic basins in question. The measurements were made for two flooding points found in the city of Carazinho – RS, located on Marquês do Pombal Street and São Bento Avenue, due to the obstruction of gutters and street inlets, paving and waterproofing of the ground due to urbanization, lack of maintenance and cleaning of the micro drainage system along with the inability of the system to collect all the volume of water from the runoff. The reductions in flow rate in these areas through the use of trenches were 16% and 15% for the first and second flooding point, respectively, while the use of the delay reservoirs together with the infiltration trenches resulted in a 29% reduction in the first flooding point and 27.5% in the second flooding point. Therefore, it is evident that the use of unconventional control measures is vital to the reduction of the peaks of the flow rate and control of the surface runoff.