River corridors, even if highly modified or degraded, still provide important habitats for numerous biological species, and carry high aesthetic and economic values. One of the keys to urban stream restoration is reco...River corridors, even if highly modified or degraded, still provide important habitats for numerous biological species, and carry high aesthetic and economic values. One of the keys to urban stream restoration is recovery and maintenance of ecological flows sufficient to sustain aquatic ecosystems. In this study, the Hongje Stream in the Seoul metropolitan area of Korea was selected for evaluating a physically-based habitat with and without habitat structures. The potential value of the aquatic habitat was evaluated by a weighted usable area （WUA） using River2D, a two-dimensional hydraulic model. The habitat suitability for Zacco platypus in the Hongje Stream was simulated with and without habitat structures. The computed WUA values for the boulder, spur dike, and riffle increased by about 2%, 7%, and 131%, respectively, after their construction. Also, the three habitat structures, especially the riffle, can contribute to increasing hydraulic heterogeneity and enhancing habitat diversity.展开更多
INTRODUCTION:In-stream and watershed dynamics in urban and urbanizing areas have significant impacts on local property and infrastructure,as well as the quality of the stream itself including:water quality,habitat,phy...INTRODUCTION:In-stream and watershed dynamics in urban and urbanizing areas have significant impacts on local property and infrastructure,as well as the quality of the stream itself including:water quality,habitat,physical characteristics,and biodiversity.As land development occurs,natural vegetation and exposed soils are converted to buildings,pavement and other impervious surfaces.This leads to increased runoff during storm events as well as decreasing the time that it takes that stormwater to reach streams,wetlands,and other stormwater storage and conveyance systems.These hydrologic changes in a watershed often occur at a rapid pace which results in rapid destabilization and degradation of streams and rivers.Rivers and streams are naturally dynamic systems.They naturally erode and reshape themselves based on changes to the watershed or the stream itself.Erosion and deposition are natural processes that have always been important components of stream systems and in and of themselves are not undesirable.When natural stream dynamics are rapidly accelerated,however,an entire series of negative impacts to the stream and the biological systems that are depended on the stream occur.Rapid destabilization of streams often leads to significant bank and bed erosion that negatively impact stream health and frequently leads to negative impact to property,buildings and structures,as well as public infrastructure.Past approaches to stream bank and bed stabilization often involved channelization,armoring,and other gray infrastructure techniques to protect public and private property in the effected reaches of streams and rivers without taking into account the overall stream system dynamics.Early stabilization efforts frequently led to other unintended consequences by accelerating the rate of bank and bed erosion in untreated reaches,inadvertent flooding,and other infrastructure impacts.The complex nature of stream dynamics and fluvial geomorphology when applied to urban stream systems and significantly modified watersheds require the need for detailed analysis of the morphology of the stream.Consideration of the complex factors and processes that make up fluvial morphology are critical when selecting practices or methods of stream restoration.Many agencies and cooperative partners work to accumulate and analyze case studies and detailed research in order to develop a method of evaluating and prescribing different stream restoration techniques based on the morphologic conditions in the stream reach(Lyn D.A.,and Newton J.F.,2015).An accumulation of case studies,research,and scholarly work on stream restoration techniques and practices helps shape and inform designers across multiple agencies in order to effectively select and design restoration practices.Ultimately,in urban streams,the designer is working to establish a condition of dynamic equilibrium in the treated stream reach.Dynamic equilibrium is defined as a stream reach that is in balance with sediment transport,aggradation,degradation,and bank and bed erosion.When those characteristics are in balance based on the inputs of sediment within the watershed,the bed load and sediments the stream transports,and discharge rate and volume,then the stream is considered to be in a relatively stable state(FISRWG,1998).The selection then of stream restoration and stabilization practices in urban areas is dependent on not only the reach being treated,but also on the overall watershed dynamics.In addition to the physics of the actual practices implemented,including resistance to shear stresses and velocity of the water flow within the stream channel being treated,the practices must also take into account the larger picture of stream dynamics including sediment delivery and transport,within the watershed and not just within the treated reach.Successful urban stream restoration and stabilization techniques mimic the structures found in more undisturbed systems through the utilization of similar materials in an engineered configuration.In many streams the use of a combination of hard and soft armorment and stabilization solutions including stone,woody debris materials,modern geosynthetic reinforcement devices and native vegetation to stabilize and naturalize stream channels,thereby provided enhanced habitat,better water quality,and protecting property and infrastructure.展开更多
Phosphorus is one of the most important nutrients required to support various kinds of biodegradation processes. As this particular nutrient is not included in the activated sludge model no. 1 （ASM1）, this study ext...Phosphorus is one of the most important nutrients required to support various kinds of biodegradation processes. As this particular nutrient is not included in the activated sludge model no. 1 （ASM1）, this study extended this model in order to determine the fate of phosphorus during the biodegradation processes. When some of the kinetics parameters are modified using observed data from the restoration project of the Xuxi River in Wuxi City, China, from August 25 to 31 in 2009, the extended model shows excellent results. In order to obtain optimum values of coefficients of nitrogen and phosphorus, the mass fraction method was used to ensure that the final results were reasonable and practically relevant. The temporal distribution of the data calculated with the extended ASM1 approximates that of the observed data.展开更多
“Never doubt that a small group of thoughtful committed citizens can change the world;indeed,it is the only thing that ever has.”-Margaret Mead My partner,Denise Donahue,and I,Simone du Boise,AIA,LEED AP,NCARB are,i...“Never doubt that a small group of thoughtful committed citizens can change the world;indeed,it is the only thing that ever has.”-Margaret Mead My partner,Denise Donahue,and I,Simone du Boise,AIA,LEED AP,NCARB are,in essence,environmentalists.As licensed architects,certified general contractors,and LEED Accredited Professionals,we co-founded Cadmus Environmental Design-Build in spite of our belief that the world doesn’t really need another developer,builder,or architect,but rather because it most certainly needs environmental stewards.We also believe we have both a personal and professional responsibility to utilize our abilities and expertise to“Build A Better Environment.”Our Weatherford Place Community is a living expression of that commitment to comprehensive energy and water conservation,coupled with contributory assets that demand less and deliver more as a community.Our signature solution,the EcoCraft Hybrid^(TM)Home,provides a prescriptive method towards Net Zero Energy results.Our formula factors efficiency,conservation,and CARE(Clean,Alternative,Renewable,Energy)toward a result of zero demand.Synergistic systems and innovations that include passive solar,active solar PV,and solar thermal are key to measurable results and LEED Platinum Certifications.The EcoCraft Hybrid^(TM)Home evolves around a holistic approach that includes:low impact design;utilitarian driven and directed by the local vernacular;passive and active solar integration;engineered systems to enhance conservation measures;and in-situ analysis that integrates the past with the present.Energy efficiency,water conservation,and environmental care inform the design and construction of an artistic,comfortable,easy to care for,and healthy home that enables universal access and age-in-place abilities.Following our specific design and construction directives,all of this is achievable at price points comparable to conventional construction.展开更多
文摘River corridors, even if highly modified or degraded, still provide important habitats for numerous biological species, and carry high aesthetic and economic values. One of the keys to urban stream restoration is recovery and maintenance of ecological flows sufficient to sustain aquatic ecosystems. In this study, the Hongje Stream in the Seoul metropolitan area of Korea was selected for evaluating a physically-based habitat with and without habitat structures. The potential value of the aquatic habitat was evaluated by a weighted usable area （WUA） using River2D, a two-dimensional hydraulic model. The habitat suitability for Zacco platypus in the Hongje Stream was simulated with and without habitat structures. The computed WUA values for the boulder, spur dike, and riffle increased by about 2%, 7%, and 131%, respectively, after their construction. Also, the three habitat structures, especially the riffle, can contribute to increasing hydraulic heterogeneity and enhancing habitat diversity.
文摘INTRODUCTION:In-stream and watershed dynamics in urban and urbanizing areas have significant impacts on local property and infrastructure,as well as the quality of the stream itself including:water quality,habitat,physical characteristics,and biodiversity.As land development occurs,natural vegetation and exposed soils are converted to buildings,pavement and other impervious surfaces.This leads to increased runoff during storm events as well as decreasing the time that it takes that stormwater to reach streams,wetlands,and other stormwater storage and conveyance systems.These hydrologic changes in a watershed often occur at a rapid pace which results in rapid destabilization and degradation of streams and rivers.Rivers and streams are naturally dynamic systems.They naturally erode and reshape themselves based on changes to the watershed or the stream itself.Erosion and deposition are natural processes that have always been important components of stream systems and in and of themselves are not undesirable.When natural stream dynamics are rapidly accelerated,however,an entire series of negative impacts to the stream and the biological systems that are depended on the stream occur.Rapid destabilization of streams often leads to significant bank and bed erosion that negatively impact stream health and frequently leads to negative impact to property,buildings and structures,as well as public infrastructure.Past approaches to stream bank and bed stabilization often involved channelization,armoring,and other gray infrastructure techniques to protect public and private property in the effected reaches of streams and rivers without taking into account the overall stream system dynamics.Early stabilization efforts frequently led to other unintended consequences by accelerating the rate of bank and bed erosion in untreated reaches,inadvertent flooding,and other infrastructure impacts.The complex nature of stream dynamics and fluvial geomorphology when applied to urban stream systems and significantly modified watersheds require the need for detailed analysis of the morphology of the stream.Consideration of the complex factors and processes that make up fluvial morphology are critical when selecting practices or methods of stream restoration.Many agencies and cooperative partners work to accumulate and analyze case studies and detailed research in order to develop a method of evaluating and prescribing different stream restoration techniques based on the morphologic conditions in the stream reach(Lyn D.A.,and Newton J.F.,2015).An accumulation of case studies,research,and scholarly work on stream restoration techniques and practices helps shape and inform designers across multiple agencies in order to effectively select and design restoration practices.Ultimately,in urban streams,the designer is working to establish a condition of dynamic equilibrium in the treated stream reach.Dynamic equilibrium is defined as a stream reach that is in balance with sediment transport,aggradation,degradation,and bank and bed erosion.When those characteristics are in balance based on the inputs of sediment within the watershed,the bed load and sediments the stream transports,and discharge rate and volume,then the stream is considered to be in a relatively stable state(FISRWG,1998).The selection then of stream restoration and stabilization practices in urban areas is dependent on not only the reach being treated,but also on the overall watershed dynamics.In addition to the physics of the actual practices implemented,including resistance to shear stresses and velocity of the water flow within the stream channel being treated,the practices must also take into account the larger picture of stream dynamics including sediment delivery and transport,within the watershed and not just within the treated reach.Successful urban stream restoration and stabilization techniques mimic the structures found in more undisturbed systems through the utilization of similar materials in an engineered configuration.In many streams the use of a combination of hard and soft armorment and stabilization solutions including stone,woody debris materials,modern geosynthetic reinforcement devices and native vegetation to stabilize and naturalize stream channels,thereby provided enhanced habitat,better water quality,and protecting property and infrastructure.
文摘Phosphorus is one of the most important nutrients required to support various kinds of biodegradation processes. As this particular nutrient is not included in the activated sludge model no. 1 （ASM1）, this study extended this model in order to determine the fate of phosphorus during the biodegradation processes. When some of the kinetics parameters are modified using observed data from the restoration project of the Xuxi River in Wuxi City, China, from August 25 to 31 in 2009, the extended model shows excellent results. In order to obtain optimum values of coefficients of nitrogen and phosphorus, the mass fraction method was used to ensure that the final results were reasonable and practically relevant. The temporal distribution of the data calculated with the extended ASM1 approximates that of the observed data.
文摘“Never doubt that a small group of thoughtful committed citizens can change the world;indeed,it is the only thing that ever has.”-Margaret Mead My partner,Denise Donahue,and I,Simone du Boise,AIA,LEED AP,NCARB are,in essence,environmentalists.As licensed architects,certified general contractors,and LEED Accredited Professionals,we co-founded Cadmus Environmental Design-Build in spite of our belief that the world doesn’t really need another developer,builder,or architect,but rather because it most certainly needs environmental stewards.We also believe we have both a personal and professional responsibility to utilize our abilities and expertise to“Build A Better Environment.”Our Weatherford Place Community is a living expression of that commitment to comprehensive energy and water conservation,coupled with contributory assets that demand less and deliver more as a community.Our signature solution,the EcoCraft Hybrid^(TM)Home,provides a prescriptive method towards Net Zero Energy results.Our formula factors efficiency,conservation,and CARE(Clean,Alternative,Renewable,Energy)toward a result of zero demand.Synergistic systems and innovations that include passive solar,active solar PV,and solar thermal are key to measurable results and LEED Platinum Certifications.The EcoCraft Hybrid^(TM)Home evolves around a holistic approach that includes:low impact design;utilitarian driven and directed by the local vernacular;passive and active solar integration;engineered systems to enhance conservation measures;and in-situ analysis that integrates the past with the present.Energy efficiency,water conservation,and environmental care inform the design and construction of an artistic,comfortable,easy to care for,and healthy home that enables universal access and age-in-place abilities.Following our specific design and construction directives,all of this is achievable at price points comparable to conventional construction.
