Design Of Best Management Practices Research Articles

Modeling economic-environmental-ecological trade-offs for non-point source control strategies: A case study of Dianchi lake watershed, China

Non-point source (NPS) pollution has become a primary threat to the water environment. With the implementation of numerous control projects, striking a balance between economic costs and efficiency has become an urgent issue for decision-makers. To identify the optimization solutions for best management practices (BMPs) at the watershed scale, a genetic algorithm and the Soil and Water Assessment Tool (SWAT) model were combined to evaluate the trade-offs of NPS control strategies. The BMPs considered in this model included soil testing and fertilizer application technology, integrated pest management projects, conservation tillage, lakeside belt ecological construction, forest construction, and vegetation filter strips. The decision variables are the type and size of the BMPs, with the objective of minimizing costs while simultaneously maximizing both total phosphorus (TP) reduction and ecosystem service value. TP reduction was simulated usinga calibrated SWAT model that successfully assessed NPS pollution in the Dianchi lake watershed. Considering NPS generation and transfer, three NPS control scenarios were designed: source reduction, process retention, and integrated control. The upper limits of the costs for three scenarios were 157, 4921, and 5013 million yuan, respectively. It is suggested that the ecological benefits should be taken into account in the BMPs design. This finding is conducive to generating optimized control schemes that can effectively balance the trade-offs between socioeconomic costs and environmental sustainability.

Effects of Regional Climate and BMP Type on Stormwater Nutrient Concentrations in BMPs: A Meta-Analysis.

Nutrient treatment performance of stormwater best management practices (BMPs) is highly variable. Improved nutrient management with BMPs requires a better understanding of factors that influence stormwater BMP treatment processes. We conducted a meta-analysis of vegetated BMPs in the International Stormwater BMP Database and compared influent and effluent nitrogen and phosphorus concentrations to quantify the BMP effect on nutrient management across climates. BMP effect on nutrient concentration change was compared between vegetated BMPs in wet and dry climates. We examined paired dissolved inorganic nitrogen (DIN), total nitrogen (TN), dissolved inorganic phosphorus (DIP), total phosphorus (TP), and combinations of these analytes as dissolved inorganic ratios and N:P ratios. Meta-analysis with subgroup analysis was used to determine differences between wet and dry climates and among vegetated BMP types. We found that across both wet and dry climates, BMPs leach DIP and TP, increase the fraction of dissolved inorganic P (DIP:TP), and decrease dissolved N:P ratios. Dry-climate BMPs leach DIP and TP more consistently and at a higher magnitude than wet-climate BMPs, and bioretention leaches more DIP than grass strips and swales. These findings generally align with biogeochemical cycling, differences in influent chemistry, and BMP design types and goals.

The effect of temperature, leaf wetness period, and cultivar susceptibility on boxwood blight disease development and sporulation.

Boxwood blight causes great losses to the boxwood nursery industry and landscapes in 30 states in the USA. Understanding the epidemiological factors governing disease development will be important for disease forecasting and design of best management practices. We evaluated the effect of leaf wetness period (lwp) and temperature on lesion development and sporulation on three boxwood cultivars under controlled conditions to develop predictive models for disease development. We conducted detached leaf assays at 18 to 27°C, and various lwp, with the cultivars Buxus sempervirens 'Suffruticosa' (highly susceptible), Buxus × 'Green Velvet' (moderately susceptible), and B. microphylla var. japonica 'Winter Gem' (less susceptible). Detached leaves were inoculated with 200 conidia in 50 µL of suspension and disease incidence was recorded at 3 - 13 d post inoculation (dpi). Cultivar, lwp, temperature, and most interactions significantly influenced disease development. A minimum of 5 h of leaf wetness was required for any disease. Lesion development increased most rapidly between 12 - 15 h and continued to increase to about 21 h of leaf wetness. Temperatures between 21 and 25°C were optimal for lesion development. There was about a 7-d lag between appearance of lesions and maximal incidence of sporulation. The two less-susceptible cultivars had fewer lesions than 'Suffruticosa' under the same infection conditions; in addition, leaf lesions of 'Winter Gem' exhibited delayed sporulation and sporulation from a smaller proportion of symptomatic leaves. Response surfaces were developed for each cultivar to predict the disease incidence using the lwp and dpi. Our findings will help refine disease forecast models to improve management of boxwood blight.

A Site-Scale Tool for Performance-Based Design of Stormwater Best Management Practices

The objective of this research is to develop a module for the design of best management practices based on percent pollutant removal. The module is a part of the site-scale integrated decision support tool (i-DSTss) that was developed for stormwater management. The current i-DSTss tool allows for the design of best management practices based on flow reduction. The new water quality module extends the capability of the i-DSTss tool by adding new procedures for the design of best management practices based on treatment performance. The water quality module can be used to assess the treatment of colloid/total suspended solid and dissolved pollutants. We classify best management practices into storage-based (e.g., pond) and infiltration-based (e.g., bioretention and permeable pavement) practices for design purposes. Several of the more complex stormwater tools require expertise to build and operate. The i-DSTss and its component modules including the newly added water quality module are built on an accessible platform (Microsoft Excel VBA) and can be operated with a minimum skillset. Predictions from the water quality module were compared with observed data, and the goodness-of-fit was evaluated. For percent total suspended solid removal, both R2 and Nash–Sutcliffe efficiency values were greater than 0.7 and 0.6 for infiltration-based and storage-based best management practices, respectively, demonstrating a good fit for both types of best management practices. For percent total phosphorous and Escherichia. coli removal, R2 and Nash–Sutcliffe efficiency values demonstrated an acceptable fit. To enhance usability of the tool by a broad range of users, the tool is designed to be flexible allowing user interaction through a graphical user interface.

Integrating watershed and ecosystem service models to assess best management practice efficiency: guidelines for Lake Erie managers and watershed modellers

Lake Erie is the shallowest and most biologically productive system of the Great Lakes, surrounded by large urban, industrial, and agricultural areas. This combination prompted extensive efforts to promote best management practices (BMPs) to mitigate non-point source pollution in Lake Erie’s watershed. Recent technical and conceptual advancements caution that significant variability exists in the BMP efficiency to reduce the severity of runoff and nutrient concentrations due to differences in implementation, the dependence of operational performance on local soil and climatic conditions, storm events and seasonality, and declining performance over time owing to imperfect maintenance. Given the uncertainty surrounding the design and efficiency of BMPs in abating non-point source pollution, our primary objective is to review the critical strengths and potential weaknesses of nine agricultural BMPs promoted for use in the Lake Erie watershed. We examine the capacity of the current generation of watershed process-based models to recreate possible BMP-mediated changes in the water and nutrient cycles. After reviewing modelling strategies (dynamic, external forcing, and empirical) to recreate non-linear watershed responses and feedback loops to BMP efficiency, our study recommends adopting dynamic representations of the interplay among key mechanisms, like soil moisture, water table, nutrient availability, plant uptake, and subsequent growth. Notwithstanding the increased sophistication of complex mathematical models, their learning capacity is usually compromised by the coarse resolution of environmental data and limited empirical knowledge to accurately parameterize environmental properties and partially understood biogeochemical processes. Moreover, BMPs may differentially affect the provisions of an ecosystem (e.g., a BMP may amplify one ecosystem service while dampening another). In this context, we highlight the expression of the value of ecosystem services in monetary and non-monetary terms as a critical information piece when considering trade-offs among costly and diverse policy decisions. Our study also examines the degree to which different types of valuation methods, socioeconomic models, and data have been operationalized in Lake Erie. Consistent with the Integrated Watershed Management framework, we advocate the adoption of a rigorous mass-balance approach to assess the impact of BMPs on nutrient cycles, as well as the integration of the projected environmental improvements with terrestrial ecosystem services, beneficial use impairments, and aquatic ecosystem services. The proposed strategy has the potential to improve the decision-making process by identifying cost-effective management actions and balancing different goods and services provided by the agroecosystems at different time scales.

Adapting urban best management practices for resilience to long-term environmental changes.

Stormwater best management practices (BMPs) help mitigate the adverse effects of urban development on stream hydrology and water quality, and are widely specified in development requirements and watershed management plans. However, design of stormwater BMPs largely relies on experience with historic climate, which may not be a reliable guide to the future. To inform BMP design that is robust to future conditions, it is important to examine how potential changes in precipitation, temperature, and potential evapotranspiration will affect the performance of BMPs. We use continuous simulation modeling to examine BMP performance under current and potential future climatic conditions and determine the changes needed in site configuration to address future impacts. We perform modeling for five development types in five different regions of the United States and explore both conventional ("gray") and green infrastructure (GI) stormwater management approaches. If stormwater designs are adapted to address potential future climate conditions, this study suggests that the most cost-effective approaches may use both gray and green BMPs. If the magnitude of extreme weather events increases dramatically, then gray practices that provide detention storage may have better cost-effectiveness. Incorporating risk of future climate impacts into stormwater design may help communities become more resilient. PRACTITIONER POINTS: There is a risk that projected changes in meteorological forcing will negatively affect stormwater BMP performance. Under projected future climate conditions, this study suggests the most cost-effective approaches may use both gray and green BMPs. If the magnitude of extreme weather events increases dramatically, gray practices that provide detention storage may have better cost-effectiveness. Flexibility is beneficial in adaptation and resilience planning due to uncertainty in projected precipitation volume and intensity changes.

Dynamic water balance of infiltration-based stormwater best management practices

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

Co-Design of Engineered Hyporheic Zones to Improve In-Stream Stormwater Treatment and Facilitate Regulatory Approval

Green infrastructure is an increasingly popular approach to mitigate widespread degradation of urban waters from stormwater pollution. However, many stormwater best management practices (BMPs) have inconsistent water quality performance and are limited to on-site, land-based deployments. To address basin-wide pollutant loads still reaching urban streams, hyporheic zone engineering has been proposed as an in-stream treatment strategy. Recognizing that regulator and practitioner perspectives are essential for innovation in the water sector, we interviewed U.S. water management professionals about the perceived risks, opportunities, and knowledge gaps related to in-stream stormwater treatment. We used engineered hyporheic zones as a case study to understand interviewee perspectives on an emerging class of in-stream treatment technologies. Interviews revealed that many considerations for in-stream stormwater treatment are common to land-based BMPs, but in-stream BMPs have additional unique design and siting requirements. Here, we synthesize practitioner goals, their recommendations on in-stream BMP design, and open research questions related to in-stream BMPs. Many interviewees suggested pairing engineered hyporheic zones with other BMPs in a treatment train to improve in-stream treatment, while simultaneously reducing risk and cost. We discuss how treatment trains and other strategies might also help overcome regulatory hurdles for innovative stormwater treatment.

New framework for optimizing best management practices at multiple scales

The optimal design of best management practices (BMPs) is of vital importance for the control of nonpoint source (NPS) pollutants, but proper methods for multiple-scale BMP design are still lacking, especially for large-scale watersheds. In this study, a new framework (MS-BMPs) was proposed for multiscale BMP design by combining multiscale design ideas, hydrological models, cost estimators and shuffled frog leaping algorithms. In addition, the computation efficiency of BMP design was improved by modifying the memetic evolution process. This new framework was then tested in the Daning River Watershed, Three Gorges Reservoir Region, China. Based on the results, the new framework could provide more powerful convergence and optimization ability, while the rationality of BMP configuration was increased by four times. From the Pareto front of the MS-BMPs, the maximum removal of TN and TP improved by 19.42% and 14.36%, indicating a more cost-effective BMP design. This study also highlighted the priority of fertilization management in the regulation of NPS pollution. This new framework can be easily extended to any watershed to assist managers with the optimal design of BMPs.

Improving stormwater quality at source using catch basin inserts

Stormwater runoff transports contaminants, including gross pollutants (GPs) accumulated on surfaces to nearby receiving water bodies. These may clog storm drainage systems, seal side entry pits and increase dissolved pollutants in receiving water bodies. Best management practices (BMPs) such as oil and grit separators, grassed swales, vegetated filter strips, retention ponds, and catch basin inserts (CBIs) are implemented to reduce stormwater pollutants in urban runoff. However, the information on physicochemical characteristics of the pollutants are still few in literature but important to improve the design of BMPs, considering qualitative aspects, and their operation. CBIs are devices used to remove GPs at source without requiring any extra land use because they are typically mounted within a catch basin (e.g. side entry pit) or existing drain. In this study, improvement of stormwater quality was investigated at two different sites (Subiaco, a residential area and Hillarys Boat Harbour, a commercial-marine-recreational area; Western Australia) where a new CBI made of non-woven polypropylene geotextile was installed in side entry pits to capture GPs at source. Influent and effluent water from the CBIs was collected and analyzed for BOD, COD, TSS and PO4-P with maximum improvements in water quality of 90%, 88%, 88% and 26% respectively. The heavy metals in influent and effluent water were found very low and below the guideline values. Analysis of particle size distribution, specific surface area of solids, SEM images and heavy metal content (Cu, Fe, Ni, Pb, Zn, Cd) in solids showed that the residential area contained more finer particles than the commercial area but that solids in the commercial area contained greater concentrations of heavy metals than those from the residential area. The specific surface area was found to be higher in the residential area and particles were thought to be largely sourced from traffic. However, these characteristics may be monitored for longer term for more CBIs installed in different locations.

Exploring effective best management practices in the Miyun reservoir watershed, China

Miyun reservoir watershed is a major source of drinking water for China’s capital, Beijing, which has a population of 21.75 million. Recently, the capacity of the Miyun reservoir to supply clean drinking water has been threatened by increasing eutrophication (or algae bloom), mainly due to the discharge of wastewater and excessive fertilization application in the upstream watershed. Therefore, there is an urgent need to design effective best management practices (BMPs) to reduce upstream nutrient load and improve water quality in the Miyun reservoir. In this study, we built a watershed model (the Soil and Water Assessment Tool) for the Miyun Reservoir Watershed (MRW) and calibrated and validated it using long-term sediment, nitrogen (N) and phosphorus (P) data. Furthermore, we developed a Markov Chain based multi-objective optimization program to explore optimal BMPs with tradeoffs between economic costs and water quality responses. Using the watershed model and multi-objective optimization algorithms, we explored the potential effectiveness of BMPs under two scenarios that are currently being considered. Scenario 1 assumes that funding for BMP implementation comes from national grants and targets high water quality standards, whereas scenario 2 assumes funding is provided by farmers and targets water quality that meet the drinking water standards. We found substantial discrepancies between the two scenarios with respect to the types and spatial configurations of BMPs and associated economic costs, highlighting the need to reconcile concerns from different stakeholders in order to arrive at a BMP plan that all parties will agree upon. In addition, we found that cross-subwatershed coordination and targeting flood season instead of year-round water quality standards could pronouncedly reduce the economic costs of BMP implementations without substantially degrading water quality. The watershed scale optimization method developed here holds promise to serve as an effective tool to explore tradeoffs between economic costs, water quality improvements, and decision makers’ and stakeholders’ concerns in BMP design, thereby informing sustainable watershed scale water resources management and ecosystem maintenance.

Optimal Design of Stormwater Collection Networks Considering Hydraulic Performance and BMPs

Stormwater collection networks are assumed to be a critical infrastructure for cities. Performance issues in such systems could cause major problems, such as flooding. Moreover, having a stormwater collection network is not enough to avoid flooding. Mostly, flooding occurs because of decrease in network performance over the time. City managers normally try to improve the network performance by applying best management practices (BMPs) to the existing network. This approach is known to be very time consuming and expensive for municipalities. In this paper, simultaneous application of BMPs with network design is evaluated. Size of the channel and BMPs area and location are designed, and optimized using the NSGA-II multi-objective genetic algorithm. Results for case study of the Tehran stormwater network showed that by designing the network with no BMP (simple design), the maximum reliability that can be achieved is about 99%. To apply BMPs on the existing network (FPMB design) using Nash bargaining method, the best answer of simple design Pareto front is selected to apply BMPs on it. By applying BMPS, reliability reaches to 100%. Finally for the third design, BMPs and network are designed simultaneously (BMP design) and Pareto front is obtained. It can be observed that all the points from the Pareto front when the network and BMPs are designed simultaneously are considered non-dominant comparing to the two previous designs. Therefore, it can be concluded that designing the network and best management practices simultaneously results in an increase in reliability and a decrease in costs.

Evaluation of the methods for quantifying particle wash-off loadings in urban impervious surfaces at small scales.

Quantifying road-deposited sediment (RDS) wash-off is critical in estimating pollutant load and for supporting the designs of urban storm water low-impact development (LID) best management practices (BMPs). The objective of this study was to identify a simple and effective small-scale wash-off load estimation and prediction method suitable for BMP engineering. The reliabilities, complexities, and applicabilities of four prediction methods (i.e., the event mean concentration (EMC) equation method, the exponential equation method, and the RDS mass difference before and after rainfall event method, and the RDS index model) were tested for three sites (i.e., a newly built area, and built-up area, and conservation area) during five natural rainfall events. Taking the calculations by the EMC method as standard results revealed the following. (1) The degree of agreement of the methods with the standard results in descending order was exponential equation method > RDS index model > RDS mass difference. (2) The degree of complexity of the studied methods in descending order was exponential equation method > the EMC equation method > the RDS index model > the RDS mass difference. (3) When considering the applicability of the models in terms of LID-BMP engineering, the RDS index model could be considered optimal for supporting the design of urban storm water BMPs.

Minimizing mosquito larval habitat within roadside stormwater treatment best management practices in southern California through incremental improvements to structure

A five-year study was conducted in Orange County, California to document the presence of standing water and the presence or absence of larval mosquitoes within 23 stormwater treatment Best Management Practices (BMPs) installed along State Route 73 by the California Department of Transportation. Findings were used to guide incremental improvements to BMP design and function with the aim of reducing the occurrence of standing water that persisted more than 96h after precipitation. During the first year of monitoring, a number of structural and non-structural factors were identified as causes for standing water within BMPs suitable for mosquitoes. Uneven grades, inlet design and construction, and novel structural features were most frequently responsible for standing water, often exacerbated by sediment and debris accumulations and periodic or perennial non-stormwater flows. Subsequent modifications to BMPs eliminated or reduced the size of persistent standing water pools. The study demonstrated that mosquito larval habitat can be mitigated in BMPs designed to remain dry between precipitation events by collecting field data that identifies where post-construction structural and managerial changes are needed to eliminate or reduce unintended sources of standing water.

Modeling Watershed‐Scale Impacts of Stormwater Management with Traditional versus Low Impact Development Design

AbstractStormwater runoff and associated pollutants from urban areas in the greater Chesapeake Bay Watershed (CBW) impair local streams and downstream ecosystems, despite urbanized land comprising only 7% of the CBW area. More recently, stormwater best management practices (BMPs) have been implemented in a low impact development (LID) manner to treat stormwater runoff closer to its source. This approach included the development of a novel BMP model to compare traditional and LID design, pioneering the use of comprehensively digitized storm sewer infrastructure and BMP design connectivity with spatial patterns in a geographic information system at the watershed scale. The goal was to compare total watershed pollutant removal efficiency in two study watersheds with differing spatial patterns of BMP design (traditional and LID), by quantifying the improved water quality benefit of LID BMP design. An estimate of uncertainty was included in the modeling framework by using ranges for BMP pollutant removal efficiencies that were based on the literature. Our model, using Monte Carlo analysis, predicted that the LID watershed removed approximately 78 kg more nitrogen, 3 kg more phosphorus, and 1,592 kg more sediment per square kilometer as compared with the traditional watershed on an annual basis. Our research provides planners a valuable model to prioritize watersheds for BMP design based on model results or in optimizing BMP selection.

Redox Dynamics and Oxygen Reduction Rates of Infiltrating Urban Stormwater beneath Low Impact Development (LID)

Low impact development (LID) best management practices (BMPs) collect, infiltrate, and treat stormwater runoff, and increase recharge to aquifers. Understanding the controls on reduction/oxidation (redox) conditions within LID BMPs is important for groundwater management because outflow from some LID BMPs can recharge aquifers and affect groundwater quality. Here we evaluate redox conditions of urban stormwater runoff in a LID infiltration trench in San Francisco, California, and quantify the relation between water saturation (%) and temperature (◦C) and resulting dissolved oxygen (DO) concentrations, redox dynamics, and O2 reduction rates. The DO fluctuations ha ve an inverse response to the duration of saturation of the trench. Anoxic (<0.5 mg/L) conditions often occurred within hours of stormwater events and persisted from a few hours to two days, which indicate that microbial respiration can be a limiting factor for DO. Temperature of stormwater runoff was not a statistically significant control on DO. The estimated O2 reduction rate is 0.003mg·L-1·min-1, which is two to five orders of magnitude higher than in groundwater from previous studies. Higher rates of O2 reduction are a function of the more toxic and organic-rich stormwater runoff that drives faster microbial O2 reduction. Our findings have important implications for the design of infiltration trenches and other LID BMPs to achieve desired redox conditions for infiltrating stormwater toward minimizing groundwater contamination.

Incorporating water quality responses into the framework of best management practices optimization

Determining cost-effective configurations of best management practices (BMPs) is a notably complex problem, especially for large-scale watersheds. In this paper, a Markov-based simulator that has been developed to quantify water quality responses is described, and a new framework is also proposed for the optimal design of BMPs by integrating the Markov approach, a watershed model, and an evolutionary algorithm. This new framework was then tested in a typical watershed, the Three Georges Reservoir Region in China. The results obtained from this application indicate the integration of water quality responses is vital for the optimal design of BMPs, especially for the downstream areas of the targeted river assessment section. The Markov-based algorithm had a computational advantage over traditional algorithm and this new algorithm offers the prospect of providing more cost-effective medium-cost solutions. The relative impacts of upstream BMPs were also highlighted in protecting water quality at multiple river assessment sections. This new algorithm can easily be extended to any other watershed to aid decision managers in the optimal design of BMPs at the watershed scale.

Overland Transport of Rotavirus and the Effect of Soil Type and Vegetation

Soil and vegetation are two critical factors for controlling the overland transport kinetics of pathogens in a natural environment. With livestock operations moving more towards concentrated animal operations, the need to dispose of a very large amount of manure in a localized area is becoming increasingly important. Animal manure contains a substantial amount of microbial pathogens, including rotavirus, which may pose a threat of contamination of water resources. This study examined the kinetics of rotavirus in overland transport, with an overall objective of optimizing the design of best management practices, especially vegetative filter strips. The overland transport of rotavirus was studied using three soil types (Catlin silt-loam, Darwin silty-clay, Alvin fine sandy-loam), spanning the entire spectrum of typical Illinois soil textures. A 20-min rainfall event was produced using a small-scale (1.07 m × 0.66 m) laboratory rainfall simulator over a soil box measuring 0.610 m × 0.305 m. Each soil type was tested for rotavirus transport kinetics with bare surface conditions, as well as with Smooth Brome and Fescue vegetative covers. Surface runoff, near-surface runoff, soil cores, and vegetation were each analyzed for infective rotavirus particles using cell-culture infectivity assays. Results show that vegetation reduces the recovery of infective rotavirus particles in surface runoff by an average of 73%, in addition to delaying the time to peak recovery. The vegetation, in general, appeared to decrease the recovery of infective rotavirus particles in surface runoff by impeding surface flow and increasing the potential for infiltration into the soil profile.

WATER SHED MANAGEMENT AND POLICIES IN INDIA

A watershed is simply the geographic area through which water flows across the land and drains into a common body of water, whether a stream, river, lake, or ocean. The watershed boundary will more or less follow the highest ridgeline around the stream channels and meet at the bottom or lowest point of the land where water flows out of the watershed, the mouth of the waterway. Much of the water comes from rainfall and storm water runoff. The quality and quantity of storm water is affected by all the alterations to the land--mining, agriculture, roadways, urban development, and the activities of people within a watershed. Watersheds are usually separated from other watersheds by naturally elevated areas.
 Management of the environment has been primarily focused on specific issues such as air, land, and water. Most efforts have resulted in decreasing pollutant emissions to air and water, improved landfills, remediation of waste sites and contaminated groundwater, protection of rare and endangered species, design of best management practices to control water and contaminant runoff, and much more. 
 What is still a continuing problem for our waters are nonpoint source pollution and habitat degradation. These are the problems that are responsible for most of the water quality use impairments throughout. These are typically complex problems that are difficult to manage. Both nonpoint pollution and habitat degradation generally cross program purviews. To establish a method to tackle these remaining problems managements must come together to better understand the interactions between the environmental components and the actions that can be taken by all towards the goal of ecosystem integrity.

Effects of distributed and centralized stormwater best management practices and land cover on urban stream hydrology at the catchment scale

Summary Urban stormwater runoff remains an important issue that causes local and regional-scale water quantity and quality issues. Stormwater best management practices (BMPs) have been widely used to mitigate runoff issues, traditionally in a centralized manner; however, problems associated with urban hydrology have remained. An emerging trend is implementation of BMPs in a distributed manner (multi-BMP treatment trains located on the landscape and integrated with urban design), but little catchment-scale performance of these systems have been reported to date. Here, stream hydrologic data (March, 2011–September, 2012) are evaluated in four catchments located in the Chesapeake Bay watershed: one utilizing distributed stormwater BMPs, two utilizing centralized stormwater BMPs, and a forested catchment serving as a reference. Among urban catchments with similar land cover, geology and BMP design standards (i.e. 100-year event), but contrasting placement of stormwater BMPs, distributed BMPs resulted in: significantly greater estimated baseflow, a higher minimum precipitation threshold for stream response and maximum discharge increases, better maximum discharge control for small precipitation events, and reduced runoff volume during an extreme (1000-year) precipitation event compared to centralized BMPs. For all catchments, greater forest land cover and less impervious cover appeared to be more important drivers than stormwater BMP spatial pattern, and caused lower total, stormflow, and baseflow runoff volume; lower maximum discharge during typical precipitation events; and lower runoff volume during an extreme precipitation event. Analysis of hydrologic field data in this study suggests that both the spatial distribution of stormwater BMPs and land cover are important for management of urban stormwater runoff. In particular, catchment-wide application of distributed BMPs improved stream hydrology compared to centralized BMPs, but not enough to fully replicate forested catchment stream hydrology. Integrated planning of stormwater management, protected riparian buffers and forest land cover with suburban development in the distributed-BMP catchment enabled multi-purpose use of land that provided esthetic value and green-space, community gathering points, and wildlife habitat in addition to hydrologic stormwater treatment.