Stormwater Management Programs 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.

Willingness to pay for ecosystem benefits of green stormwater infrastructure in Chinese sponge cities

Globally, green stormwater infrastructure (GSI) has been adopted to address urban flash flooding and stormwater pollution and provide additional ecosystem benefits such as recreation, education, and aesthetics to urban communities. However, there has been a lack of research on people's preferences for different ecosystem benefits, making it challenging to understand synergies and trade-offs among co-benefits and optimize GSI planning and design. Additionally, urban stormwater management programs commonly face long-term financial challenges, demanding research that investigates the feasibility of public utility programs. This study fills these gaps in a Chinese context by employing a discrete choice experiment (DCE) to compare public preferences and estimate the monetary values of four GSI benefits, including stormwater quantity and quality treatment, educational benefit, aesthetics, and recreational benefits, in four small-to-medium pilot sponge cities. Results show that respondents preferred some kinds of GSI programs to a conventional lawn space in their living environments, and they had significant willingness to pay (WTP) for GSI programs to obtain educational ($14.8 per household per year, p < 0.001) and recreational benefits ($10.8 per household per year, p < 0.001). Stormwater treatment, as the environmental benefit prioritized by governmental agencies, however, did not generate a significant willingness to pay in any studied cities. Residents also showed indifference towards three different planting aesthetic styles (i.e., formal vs. mixed vs. naturalistic). We conclude that providing social-oriented benefits such as education and recreation is more likely to garner urban residents' financial support for GSI development in the chosen sponge cities. While stormwater utility can be a viable funding source to supplement urban stormwater management programs, people's WTP remains limited, and other financial mechanisms need to be explored.

Valuing the public benefits of green roofs

Green roofs are being incorporated into stormwater management programs around the world. While numerous studies have estimated the private benefits to the owners and residents of buildings with green roofs, the value of the multiple public benefits received by non-building residents are less well known. We use a choice experiment survey to estimate the public benefits for a proposed green roof program in Portland, Oregon, USA. These benefits include reduced combined sewer overflows, reduced urban heat island effects, and an increase in pollinators such as birds, bees and butterflies. Past investments in stormwater infrastructure have exposed some residents to poor water quality and urban flooding, so we also explore if respondents’ willingness to pay varies based on where new green roofs are located. Across models, the largest estimated benefit in our study area is from a reduction in combined sewer overflows. Model results also show that respondents prefer to not fully concentrate new green roofs in Portland’s Central City area, which is where most green roofs are currently located. Total willingness to pay estimates for the 1-year program range from around $202 to $442 per household, or $54.4 to $116.8 million for the city of Portland, Oregon, depending on program characteristics.

Municipal Stormwater Management Spending in California: Data Extraction, Compilation, and Analysis.

Communities in the U.S. fund stormwater management programs to reduce flooding and improve and protect water quality. Few studies have attempted to quantify municipal storwmater management expenditures. This task is important given efforts to meet increasing water quality standards and develop new revenue sources. The purpose of this study was to evaluate trends in municipal stormwater management expenditures across the state of California. The study identified and compiled publicly-available data on reported stormwater expenditures (spending) and budgets for local governments in California. Data were extracted from annual reports for over 160 public agencies. A standardized rubric of activities was developed and used to create a first-of-its-kind database of municipal stormwater budgets and expenditures. The results indicated that there is over $700 million in annual municipal stormwater spending, but this total does not represent all spending due to gaps in publicly-available data. Counties and flood control districts often have the largest total expenditures in a region, but in aggregate cities reported more spending statewide. Available data are not sufficient to adequately evaluate whether current spending meets regulatory requirements. Additionally, publicly-available data are inconsistent across geographic regions regulated by different agencies. The analysis offers a template for improved cost reporting of stormwater programs in U.S. municipalities, which can help answer key questions such as the sufficiency of current funding. Future research can use the method to evaluate spending in other states and regions, evaluate trends over time to improve outcomes, and refine the spending categories based on examples from other states.

Valuing stakeholder preferences for environmental benefits of stormwater ponds: Evidence from choice experiment

With population growth driving urban expansion in many cities in the United States, there is a need for a sustainable way to manage stormwater. Green stormwater infrastructure (GSI) is considered an innovative way to handle stormwater because of its potential to provide multiple ecosystem services (ES) beyond flooding reduction. However, there is limited research regarding the society's perceived value for GSI practices' co-benefits. This study utilized stated-preference data obtained from a choice experiment in an online survey of 1159 South Carolina (SC) residents to estimate a monetary value for the ES provided by wet detention ponds— the most widely adopted stormwater practice in coastal counties of SC. The benefits examined are flooding reduction, water quality, wildlife habitat, recreation, and scenic beauty. The data were analyzed using a Mixed logit formulation. Considering the differences across the state, the model was estimated separately for five counties. Findings indicate that residents are willing to pay $13.8 to $37.8 annually for a 50% improvement in pollutant removal efficiency of ponds in addition to their current stormwater fee. Also, they are willing to pay $12.5 to $42.9 per year for the nearest pond to have buffer vegetation and wildlife. They are also likely to pay $5 to $22.5 for ponds to contribute to their neighborhood's scenic beauty. Furthermore, the results indicate that respondents from three counties are willing to pay $5.4 to $13.2 for a 50% improvement in flooding reduction, while those from two counties are likely to pay $3.9 to $4.9 for ponds to have recreational benefits. The findings of the study could help stormwater managers in designing their stormwater management programs, especially for better evaluation of stormwater utility fees.

Measuring the Direct and Indirect Effect of Scientific Information on Valuing Storm Water Management Programs With a Hybrid Choice Model

AbstractWe use scientific information to develop a realistic hypothetical scenario for storm water management and water quality improvements in a stated preference valuation survey. We then provide different treatment levels of the scientific information to survey respondents. Using a hybrid choice model, we find that scientific information has no direct influence on referendum votes in favor of a storm water management program. However, different levels of scientific information have an indirect effect by influencing respondent concern about storm water runoff and by changing perceived understanding of the storm water management plan. We show that both of these effects, neither of which are apparent in standard logit models, have implications for valuing a storm water management plan. Our results suggest that researchers should be aware of how their choice on the information provided may have a subtle influence on responses in stated preference survey.

MalNPDES Phase II Stormwater Rule—Integrating Community Engagement and Engineering Education

The Engineering Program at Coastal Carolina University seeks to train future leaders who will develop and implement sustainable solutions to global challenges by engaging students in real-world, community-based projects starting with the two-course Cornerstone Sequence. The program’s vision is to: (1) increase participation of underrepresented and minority groups and address the persistent degree attainment gap in engineering; (2) create a learning and professional environment where diversity is celebrated as seminal to program success and where all students, particularly underrepresented and minority groups, thrive and excel; and (3) develop future leaders who are knowledgeable and who are able to apply scientific and engineering principles to impact the well-being of the global society and its environment. The Coastal Waccamaw Stormwater Education Consortium (CWSEC) members include six citizen science education agencies and eight municipal separate storm sewer systems (MS4s) serving Horry and Georgetown Counties in South Carolina. The mandate of the consortium is to help local governments meet EPA’s National Pollutant Discharge Elimination System (NPDES) Stormwater Management Program Phase II Rule by implementing the following Minimum Control Measures (MCM): (1) Public Education and Outreach on Stormwater Impacts, and (2) Public Participation/Involvement. The consortium and the Engineering Program have partnered on MCM (1) and (2) by: (i) Integrating consortium activities in the ENGR 199/299 Cohort Grant Challenge Cornerstone Course Sequence’s deliverables. The objective of this two-course sequence is for students to identify and formulate complex engineering problems utilizing the National Academy of Engineering’s (NAE)14 Grand Challenges for Engineering in the twenty-first century as a framework for community-based projects; and (ii) Collaborating with representatives from municipalities and educational providers that are members of the consortium to provide current stormwater-related engineering design challenges to student groups. This paper reports on an initial, successful prototype of this partnership that occurred during the 2020 fall semester. Projects were focused on various aspects of the NAE Grand Challenge—“Provide Access to Clean Water.” The long-term vision is to integrate consortium activities into the engineering curriculum while leveraging the talent of engineering students to solve stormwater challenges in the community.

FACTORS INFLUENCING THE ESTABLISHMENT OF STORMWATER UTILITIES IN THE U.S.

Communities throughout the U.S. struggle to provide basic public services to their residents, including stormwater management services and recent regulations have only added to this challenge. Increasingly, stormwater utilities are being established to fund stormwater management programs. As of 2018, there were an estimated 1,800 to 2,000 stormwater utilities in the U.S., however the establishment of these utilities has varied both temporally and spatially across the country. This research examines the factors at the national, state, and local-levels that give rise to this variation. Overall, research findings indicate that a lack of clear legal authority, presence of stormwater regulations, and political and public opposition all influence the establishment of a stormwater utility, however the influence of these factors is more nuanced than shown by previous research. Moreover, this research identified several factors that influence the setup of utilities that had not been previously identified, including variations in state-level implementation and enforcement of stormwater regulations, general public attitudes, and the robustness of a community’s baseline stormwater management program. These different factors come into play to varying degrees in individual communities and whether a community succeeds or fails in setting up a utility depends on the final balance of these factors.

FACTORS INFLUENCING THE ESTABLISHMENT OF STORMWATER UTILITIES IN THE U.S.

Communities throughout the U.S. struggle to provide basic public services to their residents, including stormwater management services and recent regulations have only added to this challenge. Increasingly, stormwater utilities are being established to fund stormwater management programs. As of 2018, there were an estimated 1,800 to 2,000 stormwater utilities in the U.S., however the establishment of these utilities has varied both temporally and spatially across the country. This research examines the factors at the national, state, and local-levels that give rise to this variation. Overall, research findings indicate that a lack of clear legal authority, presence of stormwater regulations, and political and public opposition all influence the establishment of a stormwater utility, however the influence of these factors is more nuanced than shown by previous research. Moreover, this research identified several factors that influence the setup of utilities that had not been previously identified, including variations in state-level implementation and enforcement of stormwater regulations, general public attitudes, and the robustness of a community’s baseline stormwater management program. These different factors come into play to varying degrees in individual communities and whether a community succeeds or fails in setting up a utility depends on the final balance of these factors.

Correlations of Stormwater Runoff and Quality: Urban Pavement and Property Value by Land Use at the Parcel Level in a Small Sized American City

As the urban environment keeps growing, stormwater management programs have been adopted to address unregulated nonpoint runoff and pollutants across the world. Extensive studies on stormwater runoff and quality at smaller spatial scales exist, but are rare at larger spatial scales. Using the City of Corvallis, Oregon, a small sized American city, as a test-bed, this study estimates urban stormwater runoff and quality by zoning, which specifies land uses, and by parcel, which defines land ownership using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model and high resolution land use and land cover data. The correlations between stormwater runoff volume, stormwater quality, parcel land cover sizes, and values are then analyzed and visualized in RStudio. The results indicate that stormwater runoff and quality are determined by complex biophysical processes, with strong correlations between urban spatial sizes and property values for some land uses being observed. The research results provide suggestions for low impact development applications for different land uses, and the findings in this research can be used to suggest stormwater management policy for various land uses in small sized cities.

Community-Based Social Marketing—Creating Lasting, Sustainable, Environmental Change: Case Study of a Household Stormwater Management Program in the Region of Waterloo, Ontario

With increased frequency of extreme weather events due to climate change, there is growing need for urban, small-scale adaptation and preventative measures such as stormwater management to reduce the risk of flooding. Homeowners are often reluctant to adopt preventative stormwater measures without tangible benefits or direct experience with the flooding risks or other negative externalities. Using community-based social marketing (CBSM) as a framework, we investigated how to more effectively encourage stormwater management at the household level. In collaboration with the Canadian non-profit organization, Reep Green Solutions (Region of Waterloo, Ontario), we focused on an existing program, the RAIN Home Visit (RHV), which was designed to increase engagement in pro-environmental stormwater management behaviors. Reports from the RHV were assessed, and past program participants were interviewed using a semi-structured question set to identify barriers encountered in enacting these behaviors and to assess the program for inclusion of CBSM principles and tools. Surveys were used to collect demographic data from participants. We found that while preferred behaviors were explained and incentives were provided, more thorough, clear explanation was needed for homeowners as well as incentives of suitable size and value to effectively motivate homeowners to change. Key features that should be included in future RHV programs are public commitments, follow-up, and reminders. Further research should consider risk perception impacts with CBSM, to determine how these can work together and, perhaps, which precedes the other. Some people may be more influenced by social norms to act and others by risk perception.

Investigating the hydrologic and water quality performance of trees in bioretention mesocosms

Cities across the world are increasingly utilizing green infrastructure practices as part of their stormwater management programs. Bioretention areas have become a popular green infrastructure practice due to their widespread success in improving water quality and reducing runoff generated from impervious surfaces. Several studies have demonstrated that pollutant removal performance can be improved when plants are included in bioretention design; however, while numerous benefits of trees in urban areas have been identified, little knowledge of their contributions to stormwater management in green infrastructure currently exists. To address this need, a controlled mesocosm experiment was conducted to characterize the degree of stormwater treatment provided by bioretention columns planted with one of three native tree species commonly found across the eastern United States (Acer rubrum – red maple, Pinus taeda – loblolly pine, and Quercus palustris – pin oak). Tree pollutant removal performance was compared to nonvegetated mesocosms using a semi-synthetic stormwater mixture applied to the mesocosms over a period of 17 weeks. The hydrologic benefits of each species were characterized using data-logging scales placed below the mesocosms to compare evapotranspiration (ET) rates and drainage in each configuration. Differences in pollutant removal between tree species were largely not significant, indicating the dominant role of the bioretention media in mitigating dissolved and particle-bound constituents. Mesocosms planted with red maple (Acer rubrum) had significantly greater average ET rates (3.2 mm d−1) than all other configurations, attributable to plant development and increased growth and canopy size. All mesocosms planted with trees had significantly higher ET rates than the nonvegetated mesocosms, illustrating the role of transpiration in bioretention hydrology which, depending on species, accounted for 8.2–37.5% of average daily water losses from the mesocosms during testing. These results suggest that trees contribute to bioretention hydrology through evapotranspiration, and that significant differences between species exist and are likely related to growth rate.

Stormwater Utility Fees and Credits: A Funding Strategy for Sustainability

Lack of stable and dedicated funding has been a primary challenge for municipalities in the United States to implement effective stormwater management programs. Stormwater utility fees (SUFs), as user fees, are an alternative dedicated revenue source to fund stormwater management. When complemented with stormwater utility credits or discounts, SUFs provide greater flexibility to adopting best management practices and reducing stormwater runoff at a lower overall cost to the community. While SUFs have been increasingly used, there is little systematic research on this topic. This paper reviews literature on how SUFs work, discusses the mechanisms for setting the fees, and provides examples of different rate structures from across the U.S. Then, we use the findings of the literature to evaluate SUFs as a funding strategy for stormwater management based on four revenue evaluation criteria of efficiency, equity, revenue adequacy, and feasibility. Overall, the literature indicates that stormwater utility fees are a more efficient and environmentally sustainable source of revenue that allows for long-range planning of capital improvements and operations, but their high political visibility and legal obstacles can affect their effective implementation. However, more empirical research is needed to assess these propositions. There is a lack of literature on effective SUF designs, equitable fee types, the extent to which SUFs lead to change in public behavior and their impact on business and stormwater management investments in a municipality.

Stormwater management actions under regulatory pressure: a case study of southeast Wisconsin

In the United States, new legislation has given regulatory authorities greater oversight of municipal stormwater management programs. However, estimating the impact of greater oversight on municipal actions is difficult due to the uncertainty in current compliance efforts and their associated costs. This paper seeks to fill this gap through a case study of NPDES stormwater runoff permit reports from municipalities in Southeast Wisconsin. Specifically, this study evaluates the reported actions and expenditures against socioeconomic variables to identify the relationships between cost, socioeconomics, and the best management practices (BMPs) used for compliance. Results indicate that there are distinct differences between municipalities with and without financial and personnel resources, clear high- and low-cost BMPs, and large variation in the practices municipalities implement to meet regulatory requirements. Furthermore, results suggest that regulators should take a flexible and pragmatic approach that considers individual municipal constraints and limitations when exercising greater regulatory authority.

Changing the face of STEM with stormwater research

BackgroundThe University of Maine Stormwater Management and Research Team (SMART) program began in 2014 with the goal of creating a diverse science-technology-engineering-math (STEM) pathway with community water research. The program engages female and underrepresented minority high school students in locally relevant STEM research. It focuses on creating educational experiences that are active and relevant to students that build confidence, connect knowledge and skills directly to solving problems in local communities, and support student cultural identities. The core tools of the SMART program are resources and relationships: university-designed or commercial water data collection equipment, data loggers and chemistry supplies, on-campus science and engineering training for teacher-mentors and students, and a community mentor network. The program supports an annual summer institute that trains both students and teacher-mentors and academic-year student research projects. SMART groups are formed at local schools or community centers. Activities revolve around engaging students in citizen-science to expand their understanding of the environment, developing community strategies to address the complex problem of stormwater pollution, and using the tools of science, engineering, and technology effectively. In addition, the program supports teachers and students in reaching out to local science and engineering professionals to form a mentor network for student research.ResultsOver 3 years, 220 students and 25 teachers have been trained in the science and engineering of stormwater, having taken and recorded over 4000 local water measurements (i.e., temperature, conductivity, pH). In all cohorts to date, over 75% of student participants have self-identified as either female or a racial minority. Of approximately 125 currently college-eligible former and current SMART students, more than 41% have been accepted or are enrolled in a secondary STEM degree program. In pre- and post-program surveys, female and underrepresented minority students reported that SMART activities and their relationship with mentors have increased their awareness of how stormwater affects the community and increased their interest in pursuing a STEM career.ConclusionWith its focus on problem-solving at the community level, SMART supports students in active, local, and culturally relevant science and engineering experiences that contribute to building their confidence and affirming their decision to pursue post-secondary STEM careers.

Evaluation of Continuous Monitoring as a Tool for Municipal Stormwater Management Programs

AbstractThe purpose of this study is to evaluate the uncertainty attributable to inadequate temporal sampling of stormwater discharge and water quality, and understand its implications for meeting ...

Influence of Rainfall, Model Parameters and Routing Methods on Stormwater Modelling

Quantification of the uncertainty associated with stormwater models should be analyzed before using modelling results to make decisions on urban stormwater control and management programs. In this study, the InfoWorks Integrated Catchment Modelling (ICM) rainfall-runoff model was used to simulate hydrographs at the outfall of a catchment (drainage area 8.3 ha, with 95% pervious areas) in Shenzhen, China. The model was calibrated and validated for two rainfall events with Nash-Sutcliffe efficiency >0.81. The influence of rainfall, model parameters and routing methods on outflow hydrograph of the catchment was systematically studied. The influence of rainfall was analyzed using generated rainfall distributions with random errors and systematic errors (± 30% offsets). Random errors had less influence than systematic errors on peak flow and runoff volume, especially for two rainfall events with larger depths and longer durations. The Monte Carlo simulations using 500 parameter sets were used to verify the equifinality of the nine model parameters and determine the prediction uncertainty. Most of the monitored flows were within the uncertainty range. The influence of two routing methods from rainfall excess to hydrograph was studied. The InfoWorks ICM model incorporating double quasilinear reservoir routing was found to have a larger effect on the simulated hydrographs for rainfall events having larger depths and longer durations than using the U.S. EPA’s Storm Water Management Model nonlinear reservoir routing method did.

Multiple modes of water quality impairment by fecal contamination in a rapidly developing coastal area: southwest Brunswick County, North Carolina.

Fecal contamination of surface waters is a significant problem, particularly in rapidly developing coastal watersheds. Data from a water quality monitoring program in southwest Brunswick County, North Carolina, gathered in support of a regional wastewater and stormwater management program were used to examine likely modes and sources of fecal contamination. Sampling was conducted at 42 locations at 3-4-week intervals between 1996 and 2003, including streams, ponds, and estuarine waters in a variety of land use settings. Expected fecal sources included human wastewater systems (on-site and central), stormwater runoff, and direct deposition by animals. Fecal coliform levels were positively associated with rainfall measures, but frequent high fecal coliform concentrations at times of no rain indicated other modes of contamination as well. Fecal coliform levels were also positively associated with silicate levels, a groundwater source signal, indicating that flux of fecal-contaminated groundwater was a mode of contamination, potentially elevating FC levels in impacted waters independent of stormwater runoff. Fecal contamination by failing septic or sewer systems at many locations was significant and in addition to effects of stormwater runoff. Rainfall was also linked to fecal contamination by central sewage treatment system failures. These results highlight the importance of considering multiple modes of water pollution and different ways in which human activities cause water quality degradation. Management of water quality in coastal regions must therefore recognize diverse drivers of fecal contamination to surface waters.

Innovative Technologies for Storm-Water Management Programs in Small Urbanized Areas

AbstractSmall urbanized areas (UAs) as defined by the U.S. Census and the Environmental Protection Agency (EPA) have a population between 50,000 and 100,000, and a population density of at least 1,000 people per square mile. Under Phase II of the National Pollutant Discharge Elimination System, storm-water managers in these UAs must preserve predevelopment hydrology through compliance with qualitative regulations—an often impracticable task given the limited resources of these municipal authorities and the diffuse hydrologic impacts of urbanization. The objective of this paper is to assist storm-water managers by providing a geographic information system (GIS) workflow supported by Python scripting that produces a geographic database of storm-water infrastructure that can subsequently be used to create a fully parameterized hydrologic/hydraulic model. Guidance on calibrating this model is then provided with suggestions for measuring discharge in storm sewer systems. The application of these objectives is ...

Green Infrastructure Portfolio Standard: A Tool for Local Government to Reduce Stormwater Flooding and Sewer Overflows and Improve Local Water Quality

Green Infrastructure Portfolio Standard: A Tool for Local Government to Reduce Stormwater Flooding and Sewer Overflows and Improve Local Water QualityExpanding the use of stormwater green infrastructure in municipal stormwater management programs can be a challenge. It has traditionally been approached through the adoption of ordinances that apply to new and re-development, and thus only come into play when a development project seeks a permit to move forward. The Center for Neighborhood Technology has piloted a program to gradually, but...Author(s)Hal SpragueSourceProceedings of the Water Environment FederationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Oct, 2013ISSN1938-6478DOI10.2175/193864713813692117Volume / Issue2013 / 11Content sourceWEFTECCopyright2013Word count217