Low Impact Development Design Research Articles

A holistic analysis of Chinese sponge city cases by region: Using PLS-SEM models to understand key factors impacting LID performance

Sponge city is a national sustainable stormwater management program proposed by the Chinese government to deal with urban water issues (e.g., flooding, poor water quality) brought on by climate change and urbanization. Various strategies for sponge city construction are required since environmental constraints differ regionally across the country. To identify regional variations, reveal the inner links between externalities and design elements in sponge city construction, and offer practical suggestions, efforts in two directions are made based on the data of 68 sponge city cases around China: 1) discussing design parameters of four Low Impact Development (LID) facilities, including bioretention cell, permeable pavement, grass swale, and sunken green space, under four regionalization maps of hydrologic, climatic, landform and soil texture factors, and 2) building a holistic Partial Least Squares-Structural Equation Modelling (PLS-SEM) model illustrating the relationship between local characteristics, LID system design, and LID system performance in sponge city construction. The results show that: 1) rainfall and landform factors have great impact on LID facilities design, as their depths tend to be higher in water rich areas and coastal areas. 2) LID types and areas are positively influenced (+0.745) by the total area and permeable portion of a project, while the LID system performance (water quantity and quality control) is negatively impacted (−0.407) by the rainfall amount and clay fraction. 3) comprehensive LIDs choice instead of single LID facility shows more significant effect on improving LID system performance. It is recommended to establish different design standards and assessment indexing systems tailored to local environment when constructing sponge city projects.

A Review of Recent Developments on Modeling Low Impact Development (LID) Technique

Urban areas are more susceptible to flooding and water body contamination due to the detrimental effects of urbanization. As a result, a sustainable urban drainage system, also known as low impact development (LID) technique, is required. Although this technique can be extensively applied, the planning and design processes are multi-dimensional, multi-variable, and site-specific, which must consider various local conditions and factors. Consequently, these processes can be very complicated and time-consuming for professionals, necessitating support from computer modeling. This study intends to thoroughly explore the idea of LID modeling, various available computer models, and other tools for its optimization and decision-making processes. The most recent trustworthy journal publications that addressed the subjects under discussion were reviewed. This paper used the descriptive and comparative approaches as the analytical methods. According to the findings of the review, Storm Water Management Model (SWMM) is the computer model in LID modeling that is most frequently employed. This model is a fundamental package for dynamic urban rainfall-runoff modeling, and it has the benefits of being lightweight, simple to use, and an intuitive user interface. Besides, this model is public domain (free to use), open source, and interoperable with many hydro modeling applications. A specific LID editor module is also included in this model for modeling different LID units. To acquire the best LID planning and design from multiple criteria and alternatives, it is also necessary to use metaheuristic algorithms as an optimization model and a multi-criteria decision-making (MCDM) model in addition to the rainfall-runoff model. The authors believe combining the hydrologic and hydraulics models integrated with geographical information systems (GIS), metaheuristic algorithms, and MCDM is the most comprehensive and appropriate method for LID modeling in urban watersheds.

Simulations of low impact development designs using the storm water management model

This study assessed the U.S. Environmental Protection Agency's Storm Water Management Model (SWMM) for urban water management challenges. This study conducted a sensitivity analysis to identify the most influential factors in the SWMM. Moreover, the performance of SWMM was evaluated with the HYDRUS-1D module in simulating infiltration rates. The sensitivity results showed field capacity as the most significant factor, highlighting the need for advanced modeling techniques to consider factors like field capacity. The SWMM was evaluated by the HYDRUS-1D that SWMM consistently underestimated peak infiltration rates and commenced infiltration calculations only when soil moisture exceeded field capacity. It reveals its limitations in handling unsaturated soil conditions and highlights the consideration of the matric head of the soil during the infiltration calculation in soil media. Moreover, the evaluation of bioretention areas showed larger areas resulting in more substantial flow reductions but with significant variability under different rainfall conditions. Accordingly, this result emphasizes the importance of careful consideration for environmental factors in bioretention design. This study contributes by enhancing understanding of SWMM's limitations in simulating urban water management challenges. Thus, this research will offer technical assistance to stakeholders focused on challenges such as runoff, hydrologic cycle, and urban flooding in urban areas.

Benefit–cost analysis of a low-impact development design

Abstract The urban development increase in the built-up areas leads to more impervious areas with the consequence of larger runoff. Undeniably, this excess water has many benefits. Low-impact development (LID) is one of the innovations to conserve wasted runoff water. The two LID scenarios (water storage – WS; infiltration – I) under different rainfall depths (20, 25, 30, 35 mm) are assessed using Storm Water Management Model (SWMM) and analyzed based on their benefit–cost. This study aims to evaluate the hydrological performance and the benefit–cost ratio to identify the optimal LID design. The benefit calculation is not only projected by runoff reduction aspects, but also the other opportunities aspects. Based on the hydrological performance, scenario I shows a higher runoff reduction performance than scenario WS. Based on the benefits aspects studied, scenario I provides greater benefits with more cost than the WS scenario. Rainfall depth influenced the life cycle cost with 20-mm WS scenario experiencing faster payback period than other scenarios.

Balancing upland green infrastructure and stream restoration to recover urban stormwater and nitrate load retention

Urban watersheds have experienced ecosystem degradation due to land cover change from vegetation to impervious areas. This transformation results in increased stormwater runoff, stream channel erosion and sedimentation, and both increased inputs and reduced ecosystem retention of nutrients. Ecosystem restoration practices, including terrestrial and aquatic low impact development (LID), are becoming widely implemented in urban watersheds globally. A major question is how “green” and “grey” infrastructure can be optimally balanced to shift ecohydrological behavior towards pre-urbanization conditions. Traditional stormwater engineering typically controls runoff by temporary storage (detention) and release of stormwater, while LID designs are developed to reduce runoff by a combination of infiltrating precipitation and evapotranspiration, while promoting biogeochemical retention of nutrients. These practices are often combined with stream and riparian restoration that increases nutrient retention and reduces in-stream loads. In this study, we simulated the potential impact of three types of terrestrial LID and green infrastructure (GI) on watershed runoff and nitrate (NO3–) loading to local streams, independent of detention storage effects. The treatments included increased tree canopy, vegetated roadside bioswales, and permeable pavement. We then evaluated the individual and interactive impacts of these practices on the effectiveness of NO3– load reduction provided by stream restoration, which is affected by the altered runoff and nutrient loading caused by the LID and GI. Urban reforestation provided the highest effectiveness in terms of reducing stormflow and nutrient export, while bioswales and permeable pavement unexpectedly increased in-stream NO3– loads. Retrofit of the previously developed watershed by LID/GI alone may not provide sufficient mitigation in stormwater and nutrient loads, and should be balanced with additional grey infrastructure, such as detention ponds, rain cisterns, and sewer system upgrades.

Low-impact development (LID) control feasibility in a small-scale urban catchment for altered climate change scenarios

ABSTRACT Rainfall is considered a major input in designing stormwater management measures, especially for any low-impact development (LID) control design. With the impact of climate change, rainfall frequency and its patterns are changing continuously. Quantification of these changes and their impact on the performance of LID design becomes crucial. This paper presents a methodology to quantify the change in rainfall patterns using the Coupled Model Intercomparison Project 5 (CMIP5) climate model and to select the most feasible LID for a catchment with haphazard development. Interconnected decentralization-based LID controls are evaluated with the objective of emulating a pre-urbanized scenario. The overall analyses indicated that green roof (GR) followed by infiltration trenches (IT), rooftop disconnection (RTD), and permeable pavement (PP) showed better performance. Furthermore, a combination of IT, PP, and RTD accomplishes better efficiency for extreme rainfall events. Implementation of the most feasible combination will provide the additional benefit of water recycle and reuse.

Optimizing Low Impact Development for Stormwater Runoff Treatment: A Case Study in Yixing, China

Low-impact development (LID) practices have been recognized as a promising strategy to control urban stormwater runoff and non-point source pollution in urban ecosystems. However, many experimental and modeling efforts are required to tailor an effective LID practice based on the hydraulic and environmental characteristics of a given region. In this study, the InfoWorks ICM was applied to simulate the runoff properties and determine the optimal LID design in a residential site at Yixing, China, based on four practical rainfall events. Additionally, the software was redeveloped using Ruby object-oriented programming to improve its efficiency in uncertainty analysis using the Generalized Likelihood Uncertainty Estimation method. The simulated runoff was in good agreement with the observed discharge (Nash–Sutcliffe model efficiency coefficients >0.86). The results of the response surface method indicated that when the sunken green belt, permeable pavement, and green roof covered 8.6%, 15%, and 10%, respectively, of the 11.3 ha study area, the designed system showed the best performance with relatively low cost. This study would provide new insights into designing urban rainfall-runoff pollution control systems.

Assessing Hydrological Performances of Bioretention Cells to Meet the LID Goals

BRCs (bioretention cells), one of many low-impact development (LID) practices, are increasingly utilized to lessen the amount of runoff while simultaneously improving the runoff quality. Because the goal of BRCs and LID designs, in general, is to mimic or replicate the pre-development hydrology, it is critical to evaluate the hydrologic and ecologic performances of the BRC facility from the perspective of replicating the pre-development hydrology. The metrics developed in this study were intended to represent the hydrologic regime including the runoff volume control metrics, peak flow frequency exceedance curve, and flow duration curve. We also used a hydrological indicator of T0.5, the fraction of a multi-year period in which the flow exceeds the 0.5-year return period storm to represent the performances regarding downstream ecology. The indicators were compared to their pre-development values to determine how closely they reflected and replicated the pre-development state. A long-term stormwater management model (SWMM) model was developed to examine conditions before and after development and water movement in BRCs. When the BRCs facilities areas are 5% of the entire impervious study area, key findings show that: (1) BRCs have significant runoff volume control performances. (2) The peak flow frequency exceedance curve with BRCs could fully match the pre-development scenario for minor rainfall events compared to the 0.1-year storm. Flow duration curves with BRCs showed that, the frequency, magnitude, and duration of small flows that occurred for more than 90% of the total time closely matched those of pre-development hydrology. (3) T0.5 with BRCs showed significant improvement compared with the value of the area with no BRCs and was close to the pre-development T0.5. The findings presented in this study indicated the significant performance of BRCs in improving downstream ecology.

Optimal designs of LID based on LID experiments and SWMM for a small-scale community in Tianjin, north China

Urban flooding and waterlogging are becoming increasingly serious due to rapid urbanization and climate change. The stormwater management philosophy of low-impact development (LID) has been applied in urban construction to alleviate these problems. The selection and placement of LID designs are the most important tasks. In this study, LID experiments were performed to calibrate the Storm Water Management Model (SWMM). Then, a multi-objective optimization model, which adopted the minimum surface runoff coefficient, surcharge time, and investment cost as objectives, was established by coupling the SWMM and non-dominated sorting genetic algorithm-II (NSGA-II). Hydrological simulations were performed with the SWMM, and optimal calculations were conducted with NSGA-II. Real-coded optimal variables containing detailed size and location information of multiple LID measures were generated, and a decision space for LID design selection was obtained. The optimization designs reduced the surface runoff coefficient from 0.7 to approximately 0.5, the conduit surcharge duration was reduced from 1.62 h to 0.04–0.47 h, and the total investment cost only ranged from 395,000–872,000 ¥. Thus, the optimization model could achieve synchronous optimization of all objectives. This study could provide valuable information for LID design with the aim of urban flooding and waterlogging control.

Field Performance of Rain Garden in Red Soil Area in Southern China

Sponge City, as a new concept in urban stormwater management, utilizes on-site or local hydrologic processes for runoff control and therefore is highly dependent on the geographical location (soil type) and site-specific climatic conditions. Field studies are valuable because of the insufficient quantity of field performance data in low-impact development (LID)-related research. Rain gardens are recommended for LID to manage stormwater. A rain garden was designed as a pilot project in Nanchang city, which is one of the typical red soil areas in southern China. Red soil is usually not conducive to runoff infiltration due to its low organic carbon, strong acidity and low permeability rainfall characteristics, but the permeability of the filter media layer is an important parameter in LID design. The construction depth of the rainwater garden was 600 mm, and 30% sand, 10% compost and 60% laterite were used as combined matrix; the permeability coefficient of medium layer was 1.48 × 10−5 m·s−1. Rainfall runoff control and pollutant removal efficiencies were studied based on the on-site conditions. The analysis of almost 2 years of field data showed that volume capture ratio of annual rainfall was 78.9%, the mean load removal of TSS, NH3-N, TP, TN, COD and NO3-N were 92.5%, 85.3%, 82.9%, 80.5%, 79.8% and 77.5%, respectively, which could meet the technical guidelines for sponge city construction in Nanchang. The research results could provide a basis for sponge city design in low organic carbon and low permeability areas.

Using AHP-PROMOTHEE for Selection of Best Low-Impact Development Designs for Urban Flood Mitigation

This work first studies the effects of several Low Impact development methods on urban flood control. The Analytic Hierarchy Process-Preference Ranking Organization Method for Enrichment Evaluation (AHP-PROMETHEE) combination method is then used to select the best design. A drainage system in Golestan town of Semnan under a 5-year return period is investigated as the case study. The LID methods are selected based on the region's conditions and facilities. Then Rain Barrel (RB), Permeable Pavement (PP), and Infiltration Trench (IT) were considered as LID methods. The RB, PP, IT, IT-PP, IT-RB, PP-RB, and IT-PP-RB are considered the best LID usage scenarios. Four analytical ranking criteria, implementation cost, hydraulic performance, environmental impact during implementation, and ease of implementation, are chosen for the ranking procedure. Also, the weight of these criteria was obtained using Analytic Hierarchy Process (AHP). Finally, after determining the weight criteria, the LID designs are ranked using the Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) method. The results of hydraulic studies demonstrate the effectiveness of the PP-RB scenario with an average reduction of 90% of peak discharge and an average reduction of 80% of total flood volume. It is also observed that the weakest performance is related to the IT scenario, with an average decrease of 60% of peak flow and 47% of total flow volume. AHP-PROMETHEE analysis showed that the simultaneous use of RB and IT with a coverage percentage of 5% and a cost of $ 57,710 reduced the total volume by 51.54% and the peak discharge by 48.8% compared to the results of the current system. According to AHP-PROMETHEE, IT-RB-5 is the best project proposed among the 70 projects studied. This study showed that the AHP-PROMETHEE method is a practical method for choosing from several LID schemes for flood control.

Exploring trade-offs between cost and peak flow reduction toward identifying optimal LID designs combining green roof and permeable pavement

ABSTRACT This study aims to apply a cost-effectiveness approach to identify optimal Low Impact Development (LID) designs for peak flow management when two specific practices are simultaneously employed: Permeable Pavement (PP) and Green Roofs (GR). Four design parameters were considered, associated with coverage ratios and underlying layer thicknesses of the LIDs. The results showed that optimal costs and parameters were more affected by the level of peak flow reduction than by storms’ intensity and duration. The best settings occurred with permeable pavement treating 100% of the adjacent impervious area. In this case, the optimal designs were dominated by smaller coverage ratios (20 to 60%) and deeper (190 to 330 mm) storage layer of PP, combined with a very small or non-existent area of GR. The findings of the present study demonstrate how the optimization of design parameters may lead to more economic LID designs and provide additional guidance for LID practice implementation and to assist in the decision-making process for the most cost-effective and sustainable solutions.

Evaluation and Optimization of Low Impact Development Designs for Sustainable Stormwater Management in a Changing Climate

The increasing intensity and frequency of extreme storms pose a growing challenge to stormwater management in highly urbanized areas. Without an adequate and appropriate stormwater system, the storms and associated floods will continue to cause significant damage to infrastructure and loss of life. Low Impact Development (LID) has become an emerging alternative to the traditional stormwater system for stormwater management. This study evaluates and optimizes applications of different combinations of LIDs to minimize flows from a catchment under past and future storm conditions. The Storm Water Management Model (SWMM), forced by observed and downscaled precipitation from Coupled Model Intercomparison Project phase 6 (CMIP6), was used to simulate the runoff and apply the LIDs in the Renton City, WA. The final results show that the performance of LIDs in reducing total runoff volume varies with the types and combinations of LIDs utilized. A 30% to 75% runoff reduction was achieved for the past and future 50 year and 100 year storms. The study demonstrates the effectiveness of LID combinations with conventional stormwater systems to manage the future runoff in the study area, which is expected to increase by 26.3% in 2050.

An efficient simulation-optimization approach based on genetic algorithms and hydrologic modeling to assist in identifying optimal low impact development designs

High rates of soil imperviousness, intensified by urbanization, have been contributing strongly to the occurrence of floods all over the world. To mitigate these impacts, Low Impact Development (LID) techniques seek to preserve the hydrology of urban catchments closer to pre-development conditions by using distributed stormwater control systems. Nevertheless, the application of these techniques is associated with a variety of challenges, including the design of the LID controls, due to the significant number of variables involved and the need to attend to multiple objectives simultaneously. In this context, the application of hydrologic simulation models integrated with optimization techniques has been recently explored as an alternative to assist in planning LID scenarios. This work aims to verify the applicability of an adaptation of the Genetic Algorithm NSGA-II, together with the hydrologic model SWMM, to assist the optimal design of a LID scenario seeking to reduce the stormwater runoff and the total costs on different return periods. This scenario has considered the combined implementation of permeable pavements, green roofs and bioretention cells. The results showed that the model was capable of finding a great variety of optimal solutions on various levels of runoff reduction, at different costs, for all return periods considered. Regarding the applicability of the optimization model as a LID design method, some limitations were found related to practical applications and possible oversizing of the subjacent layers of the LIDs. Therefore, suggestions on how to improve the model have been made to solve the identified problems.

Toward sustainable stormwater management: Understanding public appreciation and recognition of urban Low Impact Development (LID) in the San Francisco Bay Area

In the United States, regulators, planners, and designers have promoted Low Impact Development (LID) as a landscape-based approach to better manage urban stormwater for ecological benefits. However, the projects have often failed to achieve positive public responses due to their unattractive and unkempt appearances. This study provides empirical insights into public perception of urban LID practices by studying user reactions to 16 sites located in the San Francisco Bay Area—eight with LID design and eight with conventional landscape design. Most of the 502 respondents, although expressing some misconceptions and limited stormwater knowledge, showed their appreciation and recognition of the LID landscapes. This finding implies that the implementation of new LID facilities can be continued and expanded without serious concern about strong public resistance, and suggests that the design of these existing LID sites can serve as models for the future projects in the San Francisco Bay Area, along with other urban areas. The study confirms the important role of picturesque beauty, naturalness, and neatness in satisfying public expectations, especially for aesthetic and ecological landscapes. Interestingly, interpretive signs appeared to be the preferable means for motivating stormwater education and the powerful means for producing positive public reactions to LID sites, suggesting the potential of urban LID projects as the venues for public education and outreach. The study not only emphasizes the alignment of aesthetics and ecology to enhance public satisfaction, but also promotes the aesthetic qualities and didactic opportunities as the essential components of LID implementation.

The application of low impact development approaches toward achieving circularity in the water sector: A case study from Soltan Abad, shiraz, Iran

The overexploitation of available water resources across the planet has increased pressure on these limited resources to a critical level, so water has been shifted into the “take-make-use-dispose” linear model. The use of rainwater, a non-conventional water resource, as an approach could promote the alternative model of Circular Economy (CE). Over the past few decades, due to the consecutive droughts, the problem of water scarcity in Iran has reached to the point that its catastrophic effects are visible in the lives of the people. Consequently, the need for sustainable approaches such as rainwater management has gained increasing urgency in order to cover the massive gap between the demand and sustainable supply of water. Accordingly, this study establishes a Low Impact Development (LID) rainwater management scenario -multiple LID design techniques-using the Rainwater + to managing the water in one of the driest regions, Soltan Abad, of Iran. To serve this purpose, the effect of four LID facilities of bioretention, subsurface infiltrating systems, rainwater harvested cisterns, and the porous pavements were evaluated in this study. Results showed that the proposed scenario of LIDs could control 60% of annual village rainfall runoff. Also, the performance of LID devices is effective in decreasing village water stress by storing and reusing rainwater in domestic activities, general uses, and recharging the groundwater. Therefore, the implementation of these LID devices in reusing, returning water to nature will pave the way toward the circular economy.

Stormflow against streamflow – Can LID-provided storage capacity ensure performance efficiency and maintenance of pre-development flow regime?

The goal of Low Impact Development (LID) is to restore and maintain the pre-development flow regime. The static storage capacity, which is often used as a parameter in LID designs, provides the maximum capacity of an LID type and is easily quantifiable already at the design phase. However, the static storage approach does not consider the inter-event recovery of storage capacity by infiltration and evapotranspiration. This study investigated dynamic storage capacities of three stormwater management designs with increasing proportions of LID units on a 1.2 ha urban residential block in Southern Finland, to compare their cost-efficiency, as well as their potential in restoring the pre-development flow regime. The cost-efficiency of LID designs was assessed based on their ability to contribute to water losses, and on the additional construction costs required when comparing them to conventional solutions (e.g. asphalt replaced with permeable pavement). The design with a small storage capacity and a large capture ratio, i.e., the ratio of contributing area to LID area, was the least efficient albeit its small construction cost. The design with an appropriate balance between the capture ratio and the LID provided storage capacity was the most efficient option. In assessing the potential of stormwater designs in restoring the pre-development flow regime, the sum of infiltration and flow in storm sewer networks was more representative of the catchment total runoff than flow alone. Finally, an extensive simulation of a large set of differently placed LID units proved useful in a priori identification of the most influential units in the treatment train.

Enhanced nitrogen removal and mitigation of nitrous oxide emission potential in a lab-scale rain garden with internal water storage

The rain garden is a low impact development design for stormwater management. Nitrate was difficult to be removed in conventional rapid-filtration rain garden, and sometimes even with net nitrogen release, resulting in the potential nitrous oxide (N2O) emission. This study aimed to compare the conventional rapid-filtration rain garden (CON) and modified rain garden with internal water storage (IWS) in terms of the nitrogen removal, N2O emission, and the bacterial community composition. Two lab-scale rain gardens (CON and IWS) were designed and studied in simulated rainfall experiments. The IWS design showed an advantage over CON in nitrogen removal, with the total nitrogen (TN) removal efficiency of 91.3%–91.4% compared to 18.0%–53.7% in CON. For N2O emission, IWS exhibited a lower emission potential of 0.2%–0.3% of TN removed (with emission rate of 0.41–0.74 mg N2O-N/m2/h) compared to 0.2%–0.7% of TN removed in CON (with emission rate of 0.24–0.29 mg N2O-N/m2/h). Phyla of Actinobacteria, Acidobacteria, Bacteroidetes, Chloroflexi and Proteobacteria dominating in both IWS and CON. A significant difference of microbial composition was found at the genus level, especially the potential denitrifiers including Candidatus Solibacter, Haliangium, Hyphomicrobium, Lentimicrobium and Terrimonas. The different abundance of these functional denitrifiers in IWS and CON may contribute to their different nitrogen removal efficiency and N2O emission potential. This study highlighted that rain garden with IWS as an optimal option for enhancing nitrogen removal and mitigating N2O emission from stormwater systems.

Water Retention Performance at Low-Impact Development (LID) Field Sites in Taipei, Taiwan

Low-impact development (LID) aims to retain stormwater at source sites rather than achieve water drainage. The infiltration and storage of rainwater on site is the most commonly applied LID design concept, turning impervious pavements into pervious pavements. In this study, three field sites in Taipei city, Taiwan, were monitored. Two of the sites were located on campuses, and one site was a roadside location. They were constructed at different times and had distinct purposes, but the common design aspect was the infiltration function of the ground surface. We monitored the water retention performance at the above three sites and applied a verified stormwater management model (SWMM) to characterize the performance at these case sites. The observed data show that if the accumulative rainfall was lower than 20 mm, the water retention rate at each of the three case sites reached almost 50%; at 60 mm rainfall, the rate was 40%. With increased rainfall amount, the water retention rate decreased because the storage capacity was limited. Because water retention is typically controlled by the infiltration capacity, the rainfall intensity dominated the performance. At the three field sites, the water retention rate was 40% on average at a rainfall intensity below 20 mm/h. Above this rainfall intensity, the infiltration performance of the pervious pavement decreased. The verified model was applied to assess the performance at the three sites under the Taipei city drainage system design standard, i.e., the five-year recurrent period storm level, at 78.8 mm/h. The results demonstrate that the water retention rates were 9.1%, 14.2%, and 61.0% at the three sites, indicating that the pervious pavement could reduce the loading of the current stormwater drainage system. Dispersed sites should be considered in urban stormwater management to mitigate flooding risk in urban areas.

Cost Analysis of Green Infrastructure Compared to Conventional Stormwater Storage

Low Impact Development (LID), or green infrastructure, refers to a land planning and engineering design practice to address urban storm runoff. The nature of LID is to mimic the pre-development environment to retain runoff through infiltration, retention, and evaporation. Despite the fact that numerous studies have analyzed the performance of runoff volume reduction and peak flow of various green infrastructures, little is known regarding the economic benefits of adopting LID practices. In this research, three completed construction projects in the Phoenix, Arizona metropolitan area were selected to perform an alternative LID design including extensive green roof (GR) and permeable interlocking concrete pavement (PICP), to determine the cost effectiveness of using LID to reduce the use of a conventional stormwater storage system. A life cycle cost (LCC) analysis was conducted to better understand the cost benefits of applying LID to meet current drainage design criteria as per the project requirements. The results found that applying LID resulted in an average LCC saving rate of 23% compared to a conventional stormwater storage system over a 50 year service life and 15.1% over a full LID (GR+PICP) strategy. Furthermore, it was discovered that LID has little cost savings benefits when constructing above-ground retention basins due to cheaper associated construction costs.