The Financial Impact of Different Stormwater Fee Types: A Case Study of Two Municipalities in Virginia

Eight stormwater user fees (SUFs) were applied to the City of Roanoke and the Town of Blacksburg, Virginia, to determine the effect each has on how land use type impacts the sources of revenue. Roanoke is larger and includes more industrial areas, but less multifamily impervious areas than Blacksburg, which translates differently in the SUFs. Residential parcels comprise the highest percentage of the revenue in all eight SUFs in Blacksburg and four in Roanoke. For both municipalities, two specific SUFs consistently comprised the highest percentage burden for residential homeowners while three other SUFs demonstrated the highest burden for commercial parcels. Open space parcels contain little impervious area, yet account for up to 27% of the revenue in the Blacksburg Area fee structure. Industrial parcels comprise more revenue in Roanoke, averaging 10.1‐4.5% in Blacksburg. Fee types that are easier to administer (e.g., Flat fees) may not fully represent the stormwater contribution from the parcels. SUF types that more accurately represent the stormwater burden on the municipality are also more administratively intensive and are more variable with fee factors.     

Managing stormwater for urban sustainability: an evaluation of local comprehensive plans in the Chesapeake Bay watershed region

This study uses a developed plan coding protocol in evaluating the quality of 76 comprehensive plans to examine whether local comprehensive plans have adequately integrated the concepts of sustainable stormwater management. The Chesapeake Bay watershed was chosen for the investigation because degraded stormwater runoff from nearby urban and suburban jurisdictions have critically polluted the watershed. The findings indicate that the majority of local governments have not sufficiently incorporated the sustainable stormwater management principles into their comprehensive plans. Five plan components (factual basis, goals and objectives, inter-organizational cooperation, policies, tools and strategies, and implementation) appear weak in realizing the concepts. The current study concludes by providing policy implications and recommendations to increase awareness and understanding of sustainable stormwater management concepts and to produce better implementation plans that integrate stormwater, ecosystem, and environmental planning comprehensively.     

Modelling stormwater treatment systems using MUSIC: Accuracy

Urban/rural stormwater quantity modelling has been well-researched and has achieved sufficient accuracy benchmark. However, modelling stormwater runoff quality (i.e. pollutants transport associated with stormwater) are relatively difficult and largely depends on catchment characteristics/land-uses; these can be estimated with acceptable accuracy provided pollutants transport equations are established through extensive field measurements. To ensure ecologically sustainable development, several stormwater treatment systems have been proposed. Model of Urban Stormwater Improvement Conceptualisation (MUSIC) developed and widely used in Australia, estimates pollutant transport from catchments and stormwater treatment through different systems. This paper presents a study on the accuracy of MUSIC estimations for different stormwater treatment options used in Australia and abroad. Data on several field measurements on different constructed stormwater treatment systems (bioretention, grass swale and porus pavement) in Australia, Sweden, New Zealand and Scotland was collected from literatures. The experimental results were compared with MUSIC's estimations under similar conditions. In general, it has been found that MUSIC can simulate flow conditions with good accuracy, however MUSIC's predictions on the removal efficiencies of Total Suspended Solids (TSS), Total Phosphorus (TP) and Total Nitrogen (TN) are varying. Potential reasons for these discrepancies are discussed. Also, a summary table showing MUSIC's overall capability on simulating stormwater treatment efficiencies for different treatment measures has been presented.     

Comparing Costs of Onsite Best Management Practices to Nutrient Credits for Stormwater Management: A Case Study in Virginia

Best management practices (BMPs) are widely used to mitigate impacts of increased impervious surfaces on stormwater runoff. However, there is limited detailed and up‐to‐date information available on the cost of designing, constructing, and maintaining BMPs over their lifetime. The objective of this study is to analyze BMPs recently constructed by the Virginia Department of Transportation (VDOT) to quantify their total cost per pound of phosphorus removed annually. A motivating factor for the study is recent changes to regulatory guidelines in Virginia which allow for full or partial substitution of purchased nutrient credits in lieu of constructing onsite BMPs to achieve compliance with stormwater quality regulations. Results of the analysis of nine BMPs found their cost ranged from $20,100 to $74,900, in 2014 dollars, per pound ($44,313‐$165,126 per kg) of phosphorus removed. Based on these results and assuming current credit prices procured by VDOT, purchasing nutrient credits is a cost‐effective option for the agency, especially when factoring in the cost of additional right of way for the BMP. Based on this finding, we expect compliance with stormwater quality regulations through credit purchases to become more widely used in Virginia. Moving forward, we suggest more direct tracking of BMP costs to support comparisons between BMP costs across a range of types and conditions to credit purchases for meeting stormwater regulations.     

User pay financing of stormwater management: A case-study in Ottawa-Carleton, Ontario

Stormwater management upgrade and maintenance costs in the province of Ontario are significant. As capital grant programs decline, municipalities are exploring alternative means for financing the abatement of stormwater quantity and quality problems. User pay financing represents one such option. The economic, institutional and legal issues related to implementing user pay financing of stormwater management in Ontario are addressed using the Regional Municipality of Ottawa-Carleton (RMOC) as a case-study. The paper reviews the experience with user pay stormwater management programs in Canada and the USA, and recent stormwater issues and financing needs in the RMOC. The presented spreadsheet rate model is based on stormwater quantity and quality considerations and best management practices (BMPs) for various land-use categories. The modelling results vary depending on the inclusion or exemption of certain land-use categories and whether BMPs are implemented. Preliminary results indicate the monthly stormwater user charges are comparable with those charged in USA programs. In Ontario, existing statutes provide the enabling legislation for stormwater user charges, and there are no legal or regulatory barriers to implementing them. However, program we start-up costs and public perception could be significant obstacles to instituting user charges.     

Sustainable use of stormwater for irrigation case study: Manly Golf Course

Sustainability has become an increasingly used term, but what does it mean in terms of practice. This research will look at the harvesting of captured stormwater for the irrigation of urban playing fields and what the implications are for catchment hydrology, local community, and local council. This research aims to identify, understand and determine the catchment conditions that may hinder the stormwater quality and quantity for capture and reuse, as well as determining whether the stormwater harvesting will be sustainable. Research methods for this project will include systemic analysis in order to further investigate the assumptions being made in the study. Manly Golf Club has relied on groundwater extraction supplemented by potable supplies for irrigation, however potable supplies are no longer available. It has been proposed to provide irrigation supplies from stormwater via onsite storage and groundwater recharge. Monitored stormwater entering the Golf Course from the adjacent Cemetery Creek sub-catchment for pollutants, have indicated that it may be suitable for irrigation with treatment and may reduce problems generated by overuse of groundwater. The proposal will provide environmental benefit through reduced pollution loads being discharged directly to receiving waters and cessation of use of potable supplies by the Club. Social and economic benefits are expected to be gained and will be monitored as part of an ongoing research program.     

Governing green stormwater infrastructure: the Philadelphia experience

Many cities throughout the world are adopting green infrastructure techniques to reduce stormwater and sewer overflows into waterways, which is particularly problematic for places experiencing more frequent and severe rain events. Governance of green stormwater implementation is proving to be as important as the techniques themselves. Building on the climate and sustainability governance literature, we argue that effective governance requires planning across city departments, experimentation and a strategy for organisational learning. We employ a case study of Philadelphia, the first city in the United States to attempt an entirely green approach to meeting federal regulations to examine issues of governance that emerged and how they were addressed. The case study draws on interviews with fourteen public and private sector actors involved in implementation, a site visit to observe the installations and to discuss the approach with a key planner, and grey literature. We find that silos can be broken down and that if open communications and a willingness to change practices are present, obstacles cited in the literature can be overcome. The key implication is that the three elements of governance need to be built into the green infrastructure planning process. While the analysis focuses on a US city, the departments involved and the governance needs of green stormwater infrastructure are similar in cities in much of the world.     

Large-scale constructed wetlands for nutrient removal from stormwater runoff: An everglades restoration project

The South Florida Water Management District (SFWMD) constructed a wetland south of Lake Okeechobee to begin the process of removing nutrients (especially phosphorus) from agricultural stormwater runoff entering the Everglades. The project, called the Everglades Nutrient Removal (ENR) project, is a prototype for larger, similarly constructed wetlands that the SFWMD will build as part of the Everglades restoration program. This innovative project is believed to be one of the largest agricultural stormwater cleanup projects in the United States, if not in the world. This publication describes the ENR project's design, construction, and proposed operation, as well as the proposed research program to be implemented over the next few years.     

Administrative Co-management: The Case of Special-Use Forest Conservation in Vietnam

Special-use forests (SUFs) are nature protected areas in Vietnam used to conserve nature and its biodiversity. While the Vietnamese government has managed to increase the size and number of SUFs, biodiversity within these areas continues to decline. To improve protection of these SUFs, co-management has been advocated in Vietnam. Successfully implementing co-management requires decentralization of authority and a certain extent of public involvement in management activities. This paper assesses how and to what extent the governance of Vietnam’s SUFs have taken up the challenge of shifting from conventional government-based management to co-management. Current practices of (co-) management were investigated in 105 of the 143 SUFs. The results show that the type of co-management varies little between different categories of SUFs. Nevertheless, a national ‘style’ of Vietnamese co-management could be identified, labelled ‘administrative’ co-management; fostering interaction between a variety of actors, but final decision-making power on management remaining strongly in the hands of the provincial government.     

Integrated treatment and recycling of stormwater: a review of Australian practice

With the use of water approaching, and in some cases exceeding, the limits of sustainability in many locations, there is an increasing recognition of the need to utilise stormwater for non-potable requirements, thus reducing the demand on potable sources. This paper presents a review of Australian stormwater treatment and recycling practices as well as a discussion of key lessons and identified knowledge gaps. Where possible, recommendations for overcoming these knowledge gaps are given. The review of existing stormwater recycling systems focussed primarily on the recycling of general urban runoff (runoff generated from all urban surfaces) for non-potable purposes. Regulations and guidelines specific to stormwater recycling need to be developed to facilitate effective design of such systems, and to minimise risks of failure. There is a clear need for the development of innovative techniques for the collection, treatment and storage of stormwater. Existing stormwater recycling practice is far ahead of research, in that there are no technologies designed specifically for stormwater recycling. Instead, technologies designed for general stormwater pollution control are frequently utilised, which do not guarantee the necessary reliability of treatment. Performance modelling for evaluation purposes also needs further research, so that industry can objectively assess alternative approaches. Just as many aspects of these issues may have impeded adoption of stormwater, another impediment to adoption has been the lack of a practical and widely accepted method for assessing the many financial, social and ecological costs and benefits of stormwater recycling projects against traditional alternatives. Such triple-bottom-line assessment methodologies need to be trialled on stormwater recycling projects. If the costs and benefits of recycling systems can be shown to compare favourably with the costs and benefits of conventional practices this will provide an incentive to overcome other obstacles to widespread adoption of stormwater recycling.     

Nutrient contribution of leaf litter in urban stormwater

This paper investigates the nutrient contribution from leaf litter in urban waterways, using data from a gross pollutant monitoring programme in a 50 ha catchment in an inner-city suburb of Melbourne, Australia. The data indicate that the potential nutrient contribution of stormwater leaf litter (greater than 5 mm) is about two orders of magnitude smaller than the typical nutrient loads in urban stormwater. The results suggest that removing leaf litter from urban waterways will do little to reduce the total stormwater nutrient load.1998 Academic Press     

Accretion of Nutrients and Sediment by a Constructed Stormwater Treatment Wetland in the Lake Tahoe Basin

This unique study evaluates the cumulative 16‐year lifetime performance of a wetland retention basin designed to treat stormwater runoff. Sediment cores were extracted prior to basin excavation and restoration to evaluate accretion rates and the origin of materials, retention characteristics of fine particulate matter, and overall pollutant removal efficiency. The sediment and organic layers together accreted 3.2 cm of depth per year, and 7.0 kg/m²/yr of inorganic material. Average annual accretion rates in g/m²/yr were as follows: C, 280; N, 17.7; P, 3.74; S, 3.80; Fe, 194; Mn, 2.68; Ca, 30.8; Mg, 30.7; K, 12.2; Na, 2.54; Zn, 0.858; Cu, 0.203; and B, 0.03. The accretion of C, N, P and sediment was comparable to nonwastewater treatment wetlands, overall, and relatively efficient for stormwater treatment wetlands. Comparison of particle size distribution between sediment cores and suspended solids in stormwater runoff indicated the wetland was effective at removing fine particles, with sediment cores containing 25% clay and 56% silt. A majority of the accretion of most metals and P could be attributed to efficient trapping of allochthonous material, while over half the accretion of C and N could be attributed to accumulation of autochthonous organic matter. Stormwater treatment was shown to be effective when physical properties of a retention basin are combined with the biological processes of a wetland, although sediment accretion can be relatively rapid.     

Field-Level Financial Assessment of Contour Prairie Strips for Enhancement of Environmental Quality

The impacts of strategically located contour prairie strips on sediment and nutrient runoff export from watersheds maintained under an annual row crop production system have been studied at a long-term research site in central Iowa. Data from 2007 to 2011 indicate that the contour prairie strips utilized within row crop-dominated landscapes have greater than proportionate and positive effects on the functioning of biophysical systems. Crop producers and land management agencies require comprehensive information about the Best Management Practices with regard to performance efficacy, operational/management parameters, and the full range of financial parameters. Here, a farm-level financial model assesses the establishment, management, and opportunity costs of contour prairie strips within cropped fields. Annualized, depending on variable opportunity costs the 15-year present value cost of utilizing contour prairie strips ranges from $590 to $865 ha^?1 year^?1 ($240–$350 ac^?1 year^?1). Expressed in the context of “treatment area” (e.g., in this study 1 ha of prairie treats 10 ha of crops), the costs of contour prairie strips can also be viewed as $59 to about $87 per treated hectare ($24–$35 ac^?1). If prairie strips were under a 15-year CRP contract, total per acre cost to farmers would be reduced by over 85 %. Based on sediment, phosphorus, and nitrogen export data from the related field studies and across low, medium, and high land rent scenarios, a megagram (Mg) of soil retained within the watershed costs between $7.79 and $11.46 mg^?1, phosphorus retained costs between $6.97 and $10.25 kg^?1, and nitrogen retained costs between $1.59 and $2.34 kg^?1. Based on overall project results, contour prairie strips may well become one of the key conservation practices used to sustain US Corn Belt agriculture in the decades to come.     

Water quality and restoration in a coastal subdivision stormwater pond

Stormwater ponds are commonly used in residential and commercial areas to control flooding. The accumulation of urban contaminants in stormwater ponds can lead to a number of water quality problems including high nutrient, chemical contaminant, and bacterial levels. This study examined the interaction between land use and coastal pond water quality in a South Carolina residential subdivision pond. Eutrophic levels of chlorophyll and phosphorus were present in all seasons. Harmful cyanobacterial blooms were prevalent during the summer months. Microcystin toxin and fecal coliform bacteria levels were measured that exceeded health and safety standards. Low concentrations of herbicides (atrazine and 2,4-D) were also detected during summer months. Drainage from the stormwater pond may transport contaminants into the adjacent tidal creek and estuary. A survey of residents within the pond's watershed indicated poor pet waste management and frequent use of fertilizers and pesticides as possible contamination sources. Educational and outreach activities were provided to community members to create an awareness of the water quality conditions in the pond. Pond management strategies were then recommended, and selected mitigation actions were implemented. Water quality problems identified in this study have been observed in other coastal stormwater ponds of varying size and salinity, leading this project to serve as a potential model for coastal stormwater pond management.     

Green roof stormwater retention: effects of roof surface, slope, and media depth

Urban areas generate considerably more stormwater runoff than natural areas of the same size due to a greater percentage of impervious surfaces that impede water infiltration. Roof surfaces account for a large portion of this impervious cover. Establishing vegetation on rooftops, known as green roofs, is one method of recovering lost green space that can aid in mitigating stormwater runoff. Two studies were performed using several roof platforms to quantify the effects of various treatments on stormwater retention. The first study used three different roof surface treatments to quantify differences in stormwater retention of a standard commercial roof with gravel ballast, an extensive green roof system without vegetation, and a typical extensive green roof with vegetation. Overall, mean percent rainfall retention ranged from 48.7% (gravel) to 82.8% (vegetated). The second study tested the influence of roof slope (2 and 6.5%) and green roof media depth (2.5, 4.0, and 6.0 cm) on stormwater retention. For all combined rain events, platforms at 2% slope with a 4-cm media depth had the greatest mean retention, 87%, although the difference from the other treatments was minimal. The combination of reduced slope and deeper media clearly reduced the total quantity of runoff. For both studies, vegetated green roof systems not only reduced the amount of stormwater runoff, they also extended its duration over a period of time beyond the actual rain event.     

Detention Outlet Retrofit Improves the Functionality of Existing Detention Basins by Reducing Erosive Flows in Receiving Channels

By discharging excess stormwater at rates that more frequently exceed the critical flow for stream erosion, conventional detention basins often contribute to increased channel instability in urban and suburban systems that can be detrimental to aquatic habitat and water quality, as well as adjacent property and infrastructure. However, these ubiquitous assets, valued at approximately $600,000 per km² in a representative suburban watershed, are ideal candidates to aid in reversing such cycles of channel degradation because improving their functionality would not necessarily require property acquisition or heavy construction. The objective of this research was to develop a simple, cost‐effective device that could be installed in detention basin outlets to reduce the erosive power of the relatively frequent storm events (~ < two‐year recurrence) and provide a passive bypass to maintain flood control performance during infrequent storms (such as the 100‐year recurrence). Results from a pilot installation show that the Detain H₂O device reduced the cumulative sediment transport capacity of the preretrofit condition by greater than 40%, and contributed to reduced flashiness and prolonged baseflows in receiving streams. When scaling the strategy across a watershed, these results suggest that potential gains in water quality and stream channel stability could be achieved at costs that are orders of magnitude less than comparable benefits from newly constructed stormwater control measures.     

A minimum data set of water quality parameters to assess and compare treatment efficiency of stormwater facilities

Urban stormwater runoff is often of poor quality, impacting aquatic ecosystems and limiting the use of stormwater runoff for recreational purposes. Several stormwater treatment facilities (STFs) are in operation or at the pilot testing stage, but their efficiencies are neither well documented nor easily compared due to the complex contaminant profile of stormwater and the highly variable runoff hydrograph. On the basis of a review of available data sets on urban stormwater quality and environmental contaminant behavior, we suggest a few carefully selected contaminant parameters (the minimum data set) to be obligatory when assessing and comparing the efficiency of STFs. Consistent use of the minimum data set in all future monitoring schemes for STFs will ensure broad-spectrum testing at low costs and strengthen comparability among facilities. The proposed minimum data set includes: (i) fine fraction of suspended solids (<63 μm), (ii) total concentrations of zinc and copper, (iii) total concentrations of phenanthrene, fluoranthene, and benzo(b,k)fluoranthene, and (iv) total concentrations of phosphorus and nitrogen. Indicator pathogens and other specific contaminants (i.e., chromium, pesticides, phenols) may be added if recreational or certain catchment-scale objectives are to be met. Issues that need further investigation have been identified during the iterative process of developing the minimum data set.     

Effectiveness of self-identified and self-reported environmental regulations for industry: The case of stormwater runoff in the US

US environmental controls for industry include numerous regulations that rely on the regulated community to self-identify, monitor, report, or complete other requirements on their own recognizance. These include state- and federal-issued general permits for stormwater discharges associated with industrial activities, effective in 1992, with known incomplete compliance by 2004. Results demonstrate highly incomplete compliance with variation in effectiveness among studied states and urbanized regions. Texas and Oklahoma, administered by US EPA during the research period, have attained higher compliance rates than California, administered by a state agency, or Florida, also administered by US EPA. Specific program designs and implementation strategies employed by states are evaluated for impacts on states' compliance effectiveness.     

Best management practices for nutrient and sediment retention in urban stormwater runoff

Stormwater management infrastructure is utilized in urban areas to alleviate flooding caused by decreased landscape permeability from increased impervious surface cover (ISC) construction. In this study, we examined two types of stormwater detention basins, SDB-BMPs (stormwater detention basin-best management practice), and SDB-FCs (stormwater detention basin-flood control). Both are constructed to retain peak stormwater flows for flood mitigation. However, the SDB-BMPs are also designed using basin topography and wetland vegetation to provide water quality improvement (nutrient and sediment removal and retention). The objective of this study was to compare SDB (both SDB-BMP and SDB-FC) surface soil P concentrations, P saturation, and Fe chemistry with natural riparian wetlands (RWs), using sites in Fairfax County, Virginia as a model system. The SDB-BMPs had significantly greater surface soil total P (P(t)) concentrations than the RWs and SDB-FCs (831.9 +/- 32.5 kg ha(-1), 643.3 +/- 19.1 kg ha(-1), and 652.1 +/- 18.8 kg ha(-1), respectively). The soil P sorption capacities of SDB-BMPs were similar to the RWs, and were greater than those of SDB-FCs, appearing to result in greater soil P removal and retention in SDB-BMPs compared with SDB-FCs. Increased Fe concentrations and relatively greater amounts of more crystalline forms of Fe in SDB-BMP soils suggested increased sediment deposition compared with RW and SDB-FC soils. Data suggest that SDB nutrient and sediment retention is facilitated in SDB-BMPs. When stormwater management is necessary, use of SDB-BMPs instead of SDB-FCs could foster more responsible urban development and be an appropriate mitigation action for receiving aquatic ecosystems.     

Understanding heavy metal and suspended solids relationships in urban stormwater using simulated rainfall

Urban stormwater from simulated rainfall on three different landuses in Queensland State, Australia (residential, industrial, commercial) was analysed for heavy metals and physico-chemical parameters such as Dissolved Organic Carbon (DOC) and Total Suspended Solids (TSS). Rainfall events were simulated using a specially designed rainfall simulator for paved surfaces. Event mean concentration samples were separated into five different particle sizes and analysed individually for eight metal elements (Zn, Fe, Cr, Cd, Cu, Al, Mn and Pb). Multivariate data analysis was carried out for the data thus generated. It was found that DOC and TSS influence the distribution of the metals in the different particle size classes. Zn was correlated with DOC at all three sites. Similarly, Pb, Fe and Al were correlated with TSS at all sites. The distribution of Cu was found to vary between the three sites, whilst Cd concentrations were too low to assess any relationships with other parameters. No correlation between Electrical Conductivity (EC), pH and heavy metals was found at the three sites. The identification of physico-chemical parameters influencing the distribution process kinetics of heavy metals in urban stormwater will significantly enhance the efficiency of urban stormwater management systems.