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Tim D Fletcher - One of the best experts on this subject based on the ideXlab platform.
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Stormwater infiltration and the ?urban karst? ? A review
Journal of Hydrology, 2017Co-Authors: Jeremie Bonneau, Tim D Fletcher, Justin F. Costelloe, Matthew J. BurnsAbstract:Abstract The covering of native soils with impervious surfaces (e.g. roofs, roads, and pavement) prevents infiltration of rainfall into the ground, resulting in increased surface runoff and decreased groundwater recharge. When this excess water is managed using Stormwater drainage systems, flow and water quality regimes of urban streams are severely altered, leading to the degradation of their ecosystems. Urban streams restoration requires alternative approaches towards Stormwater management, which aim to restore the flow regime towards pre-development conditions. The practice of Stormwater infiltration—achieved using a range of Stormwater source-control measures (SCMs)—is central to restoring baseflow. Despite this, little is known about what happens to the infiltrated water. Current knowledge about the impact of Stormwater infiltration on flow regimes was reviewed. Infiltration systems were found to be efficient at attenuating high-flow hydrology (reducing peak magnitudes and frequencies) at a range of scales (parcel, streetscape, catchment). Several modelling studies predict a positive impact of Stormwater infiltration on baseflow, and empirical evidence is emerging, but the fate of infiltrated Stormwater remains unclear. It is not known how infiltrated water travels along the subsurface pathways that characterise the urban environment, in particular the ‘urban karst’, which results from networks of human-made subsurface pathways, e.g. Stormwater and sanitary sewer pipes and associated high permeability trenches. Seepage of groundwater into and around such pipes is possible, meaning some infiltrated Stormwater could travel along artificial pathways. The catchment-scale ability of infiltration systems to restore groundwater recharge and baseflow is thus ambiguous. Further understanding of the fate of infiltrated Stormwater is required to ensure infiltration systems deliver optimal outcomes for waterway flow regimes.
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principles for urban Stormwater management to protect stream ecosystems
Freshwater Science, 2016Co-Authors: Christopher J Walsh, Tim D Fletcher, Matthew J. Burns, Derek B Booth, Rebecca L Hale, Lan N Hoang, Grant Livingston, Megan A Rippy, Mateo Scoggins, Angela M WallaceAbstract:AbstractUrban Stormwater runoff is a critical source of degradation to stream ecosystems globally. Despite broad appreciation by stream ecologists of negative effects of Stormwater runoff, Stormwater management objectives still typically center on flood and pollution mitigation without an explicit focus on altered hydrology. Resulting management approaches are unlikely to protect the ecological structure and function of streams adequately. We present critical elements of Stormwater management necessary for protecting stream ecosystems through 5 principles intended to be broadly applicable to all urban landscapes that drain to a receiving stream: 1) the ecosystems to be protected and a target ecological state should be explicitly identified; 2) the postdevelopment balance of evapotranspiration, stream flow, and infiltration should mimic the predevelopment balance, which typically requires keeping significant runoff volume from reaching the stream; 3) Stormwater control measures (SCMs) should deliver flow r...
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urban Stormwater runoff a new class of environmental flow problem
PLOS ONE, 2012Co-Authors: Christopher J Walsh, Tim D Fletcher, Matthew J. BurnsAbstract:Environmental flow assessment frameworks have begun to consider changes to flow regimes resulting from land-use change. Urban Stormwater runoff, which degrades streams through altered volume, pattern and quality of flow, presents a problem that challenges dominant approaches to Stormwater and water resource management, and to environmental flow assessment. We used evidence of ecological response to different Stormwater drainage systems to develop methods for input to environmental flow assessment. We identified the nature of hydrologic change resulting from conventional urban Stormwater runoff, and the mechanisms by which such hydrologic change is prevented in streams where ecological condition has been protected. We also quantified the increase in total volume resulting from urban Stormwater runoff, by comparing annual streamflow volumes from undeveloped catchments with the volumes that would run off impervious surfaces under the same rainfall regimes. In catchments with as little as 5–10% total imperviousness, conventional Stormwater drainage, associated with poor in-stream ecological condition, reduces contributions to baseflows and increases the frequency and magnitude of storm flows, but in similarly impervious catchments in which streams retain good ecological condition, informal drainage to forested hillslopes, without a direct piped discharge to the stream, results in little such hydrologic change. In urbanized catchments, dispersed urban Stormwater retention measures can potentially protect urban stream ecosystems by mimicking the hydrologic effects of informal drainage, if sufficient water is harvested and kept out of the stream, and if discharged water is treated to a suitable quality. Urban Stormwater is a new class of environmental flow problem: one that requires reduction of a large excess volume of water to maintain riverine ecological integrity. It is the best type of problem, because solving it provides an opportunity to solve other problems such as the provision of water for human use.
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hydrologic shortcomings of conventional urban Stormwater management and opportunities for reform
Landscape and Urban Planning, 2012Co-Authors: Matthew J. Burns, Tim D Fletcher, Christopher J Walsh, Anthony Richard Ladson, Belinda Elizabeth HattAbstract:Conventional approaches to Stormwater management for environmental protection fail because they do not address all of the changes to the flow regime caused by conventional Stormwater drainage. In this paper, we contrasted the hydrologic effects of two conventional approaches to urban Stormwater management – (a) drainage-efficiency focused and (b) pollutant-load-reduction focused – identifying their shortcomings and contrasting their hydrologic outcomes with those of a proposed alternative approach focused on restoring important elements of the natural flow regime. Under conventional approaches, both high-flow and low-flow hydrology remain perturbed. We suggest that urban Stormwater management should emphasize the restoration or protection of natural hydrologic processes at small scales, with the aim of restoring natural flow regimes at larger scales downstream. We therefore suggest that, despite recent advances in managing Stormwater to reduce pollutant loads and peak flow rates, a more complete approach is needed, one which includes as a goal the restoration or protection of ecologically important elements of the pre-development hydrograph. We propose an approach, flow-regime management, which aims as much as possible to restore and protect ecological structure and function of urban streams by retaining the pre-urban frequency of untreated storm flows, reducing the total Stormwater runoff volume through evapotranspiration or harvesting, and delivering filtered flow rates to match pre-urban baseflow rates. We note, however, that the cumulative effects of urban Stormwater management at smaller scales on catchment-scale hydrology are not yet fully understood.
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impediments and solutions to sustainable watershed scale urban Stormwater management lessons from australia and the united states
Environmental Management, 2008Co-Authors: Seth J Wenger, Hale W Thurston, William D Shuster, Tim D Fletcher, Christopher J Walsh, Anthony Richard Ladson, Rebekah Ruth BrownAbstract:In urban and suburban areas, Stormwater runoff is a primary stressor on surface waters. Conventional urban Stormwater drainage systems often route runoff directly to streams and rivers, thus exacerbating pollutant inputs and hydrologic disturbance, and resulting in the degradation of ecosystem structure and function. Decentralized Stormwater management tools, such as low impact development (LID) or water sensitive urban design (WSUD), may offer a more sustainable solution to Stormwater management if implemented at a watershed scale. These tools are designed to pond, infiltrate, and harvest water at the source, encouraging evaporation, evapotranspiration, groundwater recharge, and re-use of Stormwater. While there are numerous demonstrations of WSUD practices, there are few examples of widespread implementation at a watershed scale with the explicit objective of protecting or restoring a receiving stream. This article identifies seven major impediments to sustainable urban Stormwater management: (1) uncertainties in performance and cost, (2) insufficient engineering standards and guidelines, (3) fragmented responsibilities, (4) lack of institutional capacity, (5) lack of legislative mandate, (6) lack of funding and effective market incentives, and (7) resistance to change. By comparing experiences from Australia and the United States, two developed countries with existing conventional Stormwater infrastructure and escalating stream ecosystem degradation, we highlight challenges facing sustainable urban Stormwater management and offer several examples of successful, regional WSUD implementation. We conclude by identifying solutions to each of the seven impediments that, when employed separately or in combination, should encourage widespread implementation of WSUD with watershed-based goals to protect human health and safety, and stream ecosystems.
Christopher J Walsh - One of the best experts on this subject based on the ideXlab platform.
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principles for urban Stormwater management to protect stream ecosystems
Freshwater Science, 2016Co-Authors: Christopher J Walsh, Tim D Fletcher, Matthew J. Burns, Derek B Booth, Rebecca L Hale, Lan N Hoang, Grant Livingston, Megan A Rippy, Mateo Scoggins, Angela M WallaceAbstract:AbstractUrban Stormwater runoff is a critical source of degradation to stream ecosystems globally. Despite broad appreciation by stream ecologists of negative effects of Stormwater runoff, Stormwater management objectives still typically center on flood and pollution mitigation without an explicit focus on altered hydrology. Resulting management approaches are unlikely to protect the ecological structure and function of streams adequately. We present critical elements of Stormwater management necessary for protecting stream ecosystems through 5 principles intended to be broadly applicable to all urban landscapes that drain to a receiving stream: 1) the ecosystems to be protected and a target ecological state should be explicitly identified; 2) the postdevelopment balance of evapotranspiration, stream flow, and infiltration should mimic the predevelopment balance, which typically requires keeping significant runoff volume from reaching the stream; 3) Stormwater control measures (SCMs) should deliver flow r...
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urban Stormwater runoff a new class of environmental flow problem
PLOS ONE, 2012Co-Authors: Christopher J Walsh, Tim D Fletcher, Matthew J. BurnsAbstract:Environmental flow assessment frameworks have begun to consider changes to flow regimes resulting from land-use change. Urban Stormwater runoff, which degrades streams through altered volume, pattern and quality of flow, presents a problem that challenges dominant approaches to Stormwater and water resource management, and to environmental flow assessment. We used evidence of ecological response to different Stormwater drainage systems to develop methods for input to environmental flow assessment. We identified the nature of hydrologic change resulting from conventional urban Stormwater runoff, and the mechanisms by which such hydrologic change is prevented in streams where ecological condition has been protected. We also quantified the increase in total volume resulting from urban Stormwater runoff, by comparing annual streamflow volumes from undeveloped catchments with the volumes that would run off impervious surfaces under the same rainfall regimes. In catchments with as little as 5–10% total imperviousness, conventional Stormwater drainage, associated with poor in-stream ecological condition, reduces contributions to baseflows and increases the frequency and magnitude of storm flows, but in similarly impervious catchments in which streams retain good ecological condition, informal drainage to forested hillslopes, without a direct piped discharge to the stream, results in little such hydrologic change. In urbanized catchments, dispersed urban Stormwater retention measures can potentially protect urban stream ecosystems by mimicking the hydrologic effects of informal drainage, if sufficient water is harvested and kept out of the stream, and if discharged water is treated to a suitable quality. Urban Stormwater is a new class of environmental flow problem: one that requires reduction of a large excess volume of water to maintain riverine ecological integrity. It is the best type of problem, because solving it provides an opportunity to solve other problems such as the provision of water for human use.
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hydrologic shortcomings of conventional urban Stormwater management and opportunities for reform
Landscape and Urban Planning, 2012Co-Authors: Matthew J. Burns, Tim D Fletcher, Christopher J Walsh, Anthony Richard Ladson, Belinda Elizabeth HattAbstract:Conventional approaches to Stormwater management for environmental protection fail because they do not address all of the changes to the flow regime caused by conventional Stormwater drainage. In this paper, we contrasted the hydrologic effects of two conventional approaches to urban Stormwater management – (a) drainage-efficiency focused and (b) pollutant-load-reduction focused – identifying their shortcomings and contrasting their hydrologic outcomes with those of a proposed alternative approach focused on restoring important elements of the natural flow regime. Under conventional approaches, both high-flow and low-flow hydrology remain perturbed. We suggest that urban Stormwater management should emphasize the restoration or protection of natural hydrologic processes at small scales, with the aim of restoring natural flow regimes at larger scales downstream. We therefore suggest that, despite recent advances in managing Stormwater to reduce pollutant loads and peak flow rates, a more complete approach is needed, one which includes as a goal the restoration or protection of ecologically important elements of the pre-development hydrograph. We propose an approach, flow-regime management, which aims as much as possible to restore and protect ecological structure and function of urban streams by retaining the pre-urban frequency of untreated storm flows, reducing the total Stormwater runoff volume through evapotranspiration or harvesting, and delivering filtered flow rates to match pre-urban baseflow rates. We note, however, that the cumulative effects of urban Stormwater management at smaller scales on catchment-scale hydrology are not yet fully understood.
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impediments and solutions to sustainable watershed scale urban Stormwater management lessons from australia and the united states
Environmental Management, 2008Co-Authors: Seth J Wenger, Hale W Thurston, William D Shuster, Tim D Fletcher, Christopher J Walsh, Anthony Richard Ladson, Rebekah Ruth BrownAbstract:In urban and suburban areas, Stormwater runoff is a primary stressor on surface waters. Conventional urban Stormwater drainage systems often route runoff directly to streams and rivers, thus exacerbating pollutant inputs and hydrologic disturbance, and resulting in the degradation of ecosystem structure and function. Decentralized Stormwater management tools, such as low impact development (LID) or water sensitive urban design (WSUD), may offer a more sustainable solution to Stormwater management if implemented at a watershed scale. These tools are designed to pond, infiltrate, and harvest water at the source, encouraging evaporation, evapotranspiration, groundwater recharge, and re-use of Stormwater. While there are numerous demonstrations of WSUD practices, there are few examples of widespread implementation at a watershed scale with the explicit objective of protecting or restoring a receiving stream. This article identifies seven major impediments to sustainable urban Stormwater management: (1) uncertainties in performance and cost, (2) insufficient engineering standards and guidelines, (3) fragmented responsibilities, (4) lack of institutional capacity, (5) lack of legislative mandate, (6) lack of funding and effective market incentives, and (7) resistance to change. By comparing experiences from Australia and the United States, two developed countries with existing conventional Stormwater infrastructure and escalating stream ecosystem degradation, we highlight challenges facing sustainable urban Stormwater management and offer several examples of successful, regional WSUD implementation. We conclude by identifying solutions to each of the seven impediments that, when employed separately or in combination, should encourage widespread implementation of WSUD with watershed-based goals to protect human health and safety, and stream ecosystems.
Matthew J. Burns - One of the best experts on this subject based on the ideXlab platform.
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Stormwater infiltration and the ?urban karst? ? A review
Journal of Hydrology, 2017Co-Authors: Jeremie Bonneau, Tim D Fletcher, Justin F. Costelloe, Matthew J. BurnsAbstract:Abstract The covering of native soils with impervious surfaces (e.g. roofs, roads, and pavement) prevents infiltration of rainfall into the ground, resulting in increased surface runoff and decreased groundwater recharge. When this excess water is managed using Stormwater drainage systems, flow and water quality regimes of urban streams are severely altered, leading to the degradation of their ecosystems. Urban streams restoration requires alternative approaches towards Stormwater management, which aim to restore the flow regime towards pre-development conditions. The practice of Stormwater infiltration—achieved using a range of Stormwater source-control measures (SCMs)—is central to restoring baseflow. Despite this, little is known about what happens to the infiltrated water. Current knowledge about the impact of Stormwater infiltration on flow regimes was reviewed. Infiltration systems were found to be efficient at attenuating high-flow hydrology (reducing peak magnitudes and frequencies) at a range of scales (parcel, streetscape, catchment). Several modelling studies predict a positive impact of Stormwater infiltration on baseflow, and empirical evidence is emerging, but the fate of infiltrated Stormwater remains unclear. It is not known how infiltrated water travels along the subsurface pathways that characterise the urban environment, in particular the ‘urban karst’, which results from networks of human-made subsurface pathways, e.g. Stormwater and sanitary sewer pipes and associated high permeability trenches. Seepage of groundwater into and around such pipes is possible, meaning some infiltrated Stormwater could travel along artificial pathways. The catchment-scale ability of infiltration systems to restore groundwater recharge and baseflow is thus ambiguous. Further understanding of the fate of infiltrated Stormwater is required to ensure infiltration systems deliver optimal outcomes for waterway flow regimes.
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principles for urban Stormwater management to protect stream ecosystems
Freshwater Science, 2016Co-Authors: Christopher J Walsh, Tim D Fletcher, Matthew J. Burns, Derek B Booth, Rebecca L Hale, Lan N Hoang, Grant Livingston, Megan A Rippy, Mateo Scoggins, Angela M WallaceAbstract:AbstractUrban Stormwater runoff is a critical source of degradation to stream ecosystems globally. Despite broad appreciation by stream ecologists of negative effects of Stormwater runoff, Stormwater management objectives still typically center on flood and pollution mitigation without an explicit focus on altered hydrology. Resulting management approaches are unlikely to protect the ecological structure and function of streams adequately. We present critical elements of Stormwater management necessary for protecting stream ecosystems through 5 principles intended to be broadly applicable to all urban landscapes that drain to a receiving stream: 1) the ecosystems to be protected and a target ecological state should be explicitly identified; 2) the postdevelopment balance of evapotranspiration, stream flow, and infiltration should mimic the predevelopment balance, which typically requires keeping significant runoff volume from reaching the stream; 3) Stormwater control measures (SCMs) should deliver flow r...
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urban Stormwater runoff a new class of environmental flow problem
PLOS ONE, 2012Co-Authors: Christopher J Walsh, Tim D Fletcher, Matthew J. BurnsAbstract:Environmental flow assessment frameworks have begun to consider changes to flow regimes resulting from land-use change. Urban Stormwater runoff, which degrades streams through altered volume, pattern and quality of flow, presents a problem that challenges dominant approaches to Stormwater and water resource management, and to environmental flow assessment. We used evidence of ecological response to different Stormwater drainage systems to develop methods for input to environmental flow assessment. We identified the nature of hydrologic change resulting from conventional urban Stormwater runoff, and the mechanisms by which such hydrologic change is prevented in streams where ecological condition has been protected. We also quantified the increase in total volume resulting from urban Stormwater runoff, by comparing annual streamflow volumes from undeveloped catchments with the volumes that would run off impervious surfaces under the same rainfall regimes. In catchments with as little as 5–10% total imperviousness, conventional Stormwater drainage, associated with poor in-stream ecological condition, reduces contributions to baseflows and increases the frequency and magnitude of storm flows, but in similarly impervious catchments in which streams retain good ecological condition, informal drainage to forested hillslopes, without a direct piped discharge to the stream, results in little such hydrologic change. In urbanized catchments, dispersed urban Stormwater retention measures can potentially protect urban stream ecosystems by mimicking the hydrologic effects of informal drainage, if sufficient water is harvested and kept out of the stream, and if discharged water is treated to a suitable quality. Urban Stormwater is a new class of environmental flow problem: one that requires reduction of a large excess volume of water to maintain riverine ecological integrity. It is the best type of problem, because solving it provides an opportunity to solve other problems such as the provision of water for human use.
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hydrologic shortcomings of conventional urban Stormwater management and opportunities for reform
Landscape and Urban Planning, 2012Co-Authors: Matthew J. Burns, Tim D Fletcher, Christopher J Walsh, Anthony Richard Ladson, Belinda Elizabeth HattAbstract:Conventional approaches to Stormwater management for environmental protection fail because they do not address all of the changes to the flow regime caused by conventional Stormwater drainage. In this paper, we contrasted the hydrologic effects of two conventional approaches to urban Stormwater management – (a) drainage-efficiency focused and (b) pollutant-load-reduction focused – identifying their shortcomings and contrasting their hydrologic outcomes with those of a proposed alternative approach focused on restoring important elements of the natural flow regime. Under conventional approaches, both high-flow and low-flow hydrology remain perturbed. We suggest that urban Stormwater management should emphasize the restoration or protection of natural hydrologic processes at small scales, with the aim of restoring natural flow regimes at larger scales downstream. We therefore suggest that, despite recent advances in managing Stormwater to reduce pollutant loads and peak flow rates, a more complete approach is needed, one which includes as a goal the restoration or protection of ecologically important elements of the pre-development hydrograph. We propose an approach, flow-regime management, which aims as much as possible to restore and protect ecological structure and function of urban streams by retaining the pre-urban frequency of untreated storm flows, reducing the total Stormwater runoff volume through evapotranspiration or harvesting, and delivering filtered flow rates to match pre-urban baseflow rates. We note, however, that the cumulative effects of urban Stormwater management at smaller scales on catchment-scale hydrology are not yet fully understood.
William D Shuster - One of the best experts on this subject based on the ideXlab platform.
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the role of trees in urban Stormwater management
Landscape and Urban Planning, 2017Co-Authors: Adam Berland, William D Shuster, Sheri A Shiflett, Ahjond S Garmestani, Haynes C Goddard, Dustin L Herrmann, Matthew E HoptonAbstract:Urban impervious surfaces convert precipitation to Stormwater runoff, which causes water quality and quantity problems. While traditional Stormwater management has relied on gray infrastructure such as piped conveyances to collect and convey Stormwater to wastewater treatment facilities or into surface waters, cities are exploring green infrastructure to manage Stormwater at its source. Decentralized green infrastructure leverages the capabilities of soil and vegetation to infiltrate, redistribute, and otherwise store Stormwater volume, with the potential to realize ancillary environmental, social, and economic benefits. To date, green infrastructure science and practice have largely focused on infiltration-based technologies that include rain gardens, bioswales, and permeable pavements. However, a narrow focus on infiltration overlooks other losses from the hydrologic cycle, and we propose that arboriculture – the cultivation of trees and other woody plants – deserves additional consideration as a Stormwater control measure. Trees interact with the urban hydrologic cycle by intercepting incoming precipitation, removing water from the soil via transpiration, enhancing infiltration, and bolstering the performance of other green infrastructure technologies. However, many of these interactions are inadequately understood, particularly at spatial and temporal scales relevant to Stormwater management. As such, the reliable use of trees for Stormwater control depends on improved understanding of how and to what extent trees interact with Stormwater, and the context-specific consideration of optimal arboricultural practices and institutional frameworks to maximize the Stormwater benefits trees can provide.
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impediments and solutions to sustainable watershed scale urban Stormwater management lessons from australia and the united states
Environmental Management, 2008Co-Authors: Seth J Wenger, Hale W Thurston, William D Shuster, Tim D Fletcher, Christopher J Walsh, Anthony Richard Ladson, Rebekah Ruth BrownAbstract:In urban and suburban areas, Stormwater runoff is a primary stressor on surface waters. Conventional urban Stormwater drainage systems often route runoff directly to streams and rivers, thus exacerbating pollutant inputs and hydrologic disturbance, and resulting in the degradation of ecosystem structure and function. Decentralized Stormwater management tools, such as low impact development (LID) or water sensitive urban design (WSUD), may offer a more sustainable solution to Stormwater management if implemented at a watershed scale. These tools are designed to pond, infiltrate, and harvest water at the source, encouraging evaporation, evapotranspiration, groundwater recharge, and re-use of Stormwater. While there are numerous demonstrations of WSUD practices, there are few examples of widespread implementation at a watershed scale with the explicit objective of protecting or restoring a receiving stream. This article identifies seven major impediments to sustainable urban Stormwater management: (1) uncertainties in performance and cost, (2) insufficient engineering standards and guidelines, (3) fragmented responsibilities, (4) lack of institutional capacity, (5) lack of legislative mandate, (6) lack of funding and effective market incentives, and (7) resistance to change. By comparing experiences from Australia and the United States, two developed countries with existing conventional Stormwater infrastructure and escalating stream ecosystem degradation, we highlight challenges facing sustainable urban Stormwater management and offer several examples of successful, regional WSUD implementation. We conclude by identifying solutions to each of the seven impediments that, when employed separately or in combination, should encourage widespread implementation of WSUD with watershed-based goals to protect human health and safety, and stream ecosystems.
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application of market mechanisms and incentives to reduce Stormwater runoff an integrated hydrologic economic and legal approach
Environmental Science & Policy, 2005Co-Authors: Punam Parikh, Michael A Taylor, Theresa Hoagland, Hale W Thurston, William D ShusterAbstract:Increased Stormwater flows are a direct result of urbanization and the consequent increase in the proportion of land area under impervious surface. Due to its contribution to abnormally high stream flows and its role as a carrier of pollutants that degrade water quality, excess Stormwater runoff has negative impacts on both terrestrial and aquatic ecosystems. In response to the increased magnitude and frequency of Stormwater runoff events, municipalities and local governments seek cost-effective strategies to manage the risks associated with these Stormwater flows. The goal of a proposed interdisciplinary approach involves providing incentives for the construction of small-scale best management practices throughout a small urban watershed, leading to a cost-effective means to control Stormwater runoff, and partially restoring a more natural hydrologic regime to a watershed area. Market mechanisms and other incentives have been suggested as plausible approaches to the reduction of Stormwater runoff. Development and implementation of market mechanisms and incentives to reduce Stormwater runoff, however, involves interdisciplinary considerations and issues. This paper develops an interdisciplinary view of the Stormwater runoff issue, beginning with a brief description of Stormwater runoff management from a hydrologic perspective. We then present a background on types of market instruments and their related incentives as possible approaches to reducing the risks associated with both the magnitude and frequency of recurrence for excess Stormwater runoff flows. This is followed by an analysis of how the federal Clean Water Act and state water laws have dealt with Stormwater issues. These perspectives and methods are synthesized to develop several Stormwater management scenarios that include Stormwater user fees, Stormwater runoff charges, allowance markets, and voluntary offset programs. Each of these programs would likely incorporate Stormwater best management practices at the watershed level, yet in different ways, and we discuss the opportunities and limitations borne out of our analysis of the legal, economic, and hydrologic considerations. # 2005 Elsevier Ltd. All rights reserved.
Anthony Richard Ladson - One of the best experts on this subject based on the ideXlab platform.
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hydrologic shortcomings of conventional urban Stormwater management and opportunities for reform
Landscape and Urban Planning, 2012Co-Authors: Matthew J. Burns, Tim D Fletcher, Christopher J Walsh, Anthony Richard Ladson, Belinda Elizabeth HattAbstract:Conventional approaches to Stormwater management for environmental protection fail because they do not address all of the changes to the flow regime caused by conventional Stormwater drainage. In this paper, we contrasted the hydrologic effects of two conventional approaches to urban Stormwater management – (a) drainage-efficiency focused and (b) pollutant-load-reduction focused – identifying their shortcomings and contrasting their hydrologic outcomes with those of a proposed alternative approach focused on restoring important elements of the natural flow regime. Under conventional approaches, both high-flow and low-flow hydrology remain perturbed. We suggest that urban Stormwater management should emphasize the restoration or protection of natural hydrologic processes at small scales, with the aim of restoring natural flow regimes at larger scales downstream. We therefore suggest that, despite recent advances in managing Stormwater to reduce pollutant loads and peak flow rates, a more complete approach is needed, one which includes as a goal the restoration or protection of ecologically important elements of the pre-development hydrograph. We propose an approach, flow-regime management, which aims as much as possible to restore and protect ecological structure and function of urban streams by retaining the pre-urban frequency of untreated storm flows, reducing the total Stormwater runoff volume through evapotranspiration or harvesting, and delivering filtered flow rates to match pre-urban baseflow rates. We note, however, that the cumulative effects of urban Stormwater management at smaller scales on catchment-scale hydrology are not yet fully understood.
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impediments and solutions to sustainable watershed scale urban Stormwater management lessons from australia and the united states
Environmental Management, 2008Co-Authors: Seth J Wenger, Hale W Thurston, William D Shuster, Tim D Fletcher, Christopher J Walsh, Anthony Richard Ladson, Rebekah Ruth BrownAbstract:In urban and suburban areas, Stormwater runoff is a primary stressor on surface waters. Conventional urban Stormwater drainage systems often route runoff directly to streams and rivers, thus exacerbating pollutant inputs and hydrologic disturbance, and resulting in the degradation of ecosystem structure and function. Decentralized Stormwater management tools, such as low impact development (LID) or water sensitive urban design (WSUD), may offer a more sustainable solution to Stormwater management if implemented at a watershed scale. These tools are designed to pond, infiltrate, and harvest water at the source, encouraging evaporation, evapotranspiration, groundwater recharge, and re-use of Stormwater. While there are numerous demonstrations of WSUD practices, there are few examples of widespread implementation at a watershed scale with the explicit objective of protecting or restoring a receiving stream. This article identifies seven major impediments to sustainable urban Stormwater management: (1) uncertainties in performance and cost, (2) insufficient engineering standards and guidelines, (3) fragmented responsibilities, (4) lack of institutional capacity, (5) lack of legislative mandate, (6) lack of funding and effective market incentives, and (7) resistance to change. By comparing experiences from Australia and the United States, two developed countries with existing conventional Stormwater infrastructure and escalating stream ecosystem degradation, we highlight challenges facing sustainable urban Stormwater management and offer several examples of successful, regional WSUD implementation. We conclude by identifying solutions to each of the seven impediments that, when employed separately or in combination, should encourage widespread implementation of WSUD with watershed-based goals to protect human health and safety, and stream ecosystems.
