Peak Flow Attenuation Research Articles

Determination of Spatially-Distributed Hydrological Ecosystem Services (HESS) in the Red River Delta Using a Calibrated SWAT Model

The principles of Integrated Water Resources Management (IWRM), conservation of natural capital, and water accounting requires Hydrological Eco-System Services (HESS) to be determined. This paper presents a modeling approach for quantifying the HESS framework using the Soil Water Assessment Tool (SWAT). SWAT was used–after calibration against remote sensing data–to quantify and spatially identify total runoff, natural livestock feed production, fuelwood from natural forests, dry season flow, groundwater recharge, root zone storage for carrying over water from wet to dry season, sustaining rainfall, peak flow attenuation, carbon sequestration, microclimate cooling, and meeting environmental flow requirements. The environmental value of the current land use and vegetation was made explicit by carrying out parallel simulations for bare soil and vegetation conditions and reporting the incremental ecosystem services. Geographical areas with more and fewer HESS are identified. The spatial and temporal variability of annual HESS services is demonstrated for the Day Basin—which is part of the Red River delta (Vietnam)—for the period 2003 to 2013. The result shows that even though the basin is abundant with HESS, e.g., 7482 m3/ha of runoff, 3820 m3/ha of groundwater recharge, the trend for many HESS values, e.g., micro-climate cooling, meeting environmental flow requirements, and rootzone storage, are declining. It is found and proven that quantified HESS indicators highlighted the provisioning and regulating characters of ecosystem services, as well as geographical hotspots across the basin. The SWAT model shows the capability of simulating terrestrial eco-hydrological processes such as climate, soil, and current land use. The methodology illustrates how eco-hydrologists can benchmark ecosystem values and include HESS in exploring river basin management scenarios, climate change studies, and land use planning.

Assessing the efficacy of offline water storage ponds for natural flood management

AbstractLand use changes, landscape modifications and changing climate have resulted in local to regional flood risk increases in recent decades. As an alternative to traditional engineering approaches, there has been a movement towards catchment‐based flood risk management, a subset of which is natural flood management (NFM). NFM aims to enhance flood resilience through the slowing and storing of runoff and flow, based on the restoration and augmentation of hydrological and morphological catchment features. However, despite research highlighting their potential benefits, there is a limited quantity of robust and science‐based empirical evidence on how these structures function in the landscape and their efficacy in reducing flood hazards. To address this knowledge gap and contribute to the growing NFM evidence base, this study evaluates the efficacy of offline water storage ponds for flow attenuation. Two contrasting pond sites in the Tone and Parrett catchment headwaters (SW‐England) were monitored from April 2018 to December 2020 for channel flow, pond volume, and rainfall. Field‐scale, high resolution (1.61 cm spatial support) digital elevation models from Structure‐from‐Motion and manual surveys were collected to quantify pond dynamics and connectivity. A comprehensive, storm definition methodology was developed for event separation, to enable quantification of the impact of pond behaviour on stream flow, across storm hydrographs. Results show that where offline ponds function as designed, with direct pond filling from the channel, peak flow attenuation can reach 7% (maximum event AEP of 83%). Smaller events, where pond filling occurs directly from rainfall or runoff display only a maximum of 3% peak flow reduction (event AEP from 83% –>99%). The ability of ponds to attenuate flow is heavily reliant on sufficient structural conditions for ponds to fill directly from the channel and to drain slowly following event peaks. This study provides an empirical database for future NFM applications, including key criteria for future design and for use as observational data in modelling applications, by upscaling the efficacy of ponds to reduce flood impacts at larger scales.

Evaluating low impact development practices potentials for increasing flood resilience and stormwater reuse through lab-controlled bioretention systems.

Low impact development practices (LID) as alternative measures of urban drainage can be used within the approach of resources recycling and co-management. This study evaluates the potential contribution of a bioretention system to flood control, non-potable water demands (NPD) and resources co-management. Bioretention setups were tested experimentally under variable conditions to identify operational key-factors to multiple purposes. Additionally, the efficiencies obtained for laboratory scale were extrapolated for household and watershed scale, quantifying the indicators of water demand reduction (WDR), energy demand reduction (EDR) and carbon emission reduction (CER) for hybrid systems with LID. The laboratory results indicated that the use of a bioretention with a submerged zone can improve the quality of the water recovered for reuse, while maintaining the efficiency of runoff retention and peak flow attenuation. Comparing the bioretention effluent quality with the Brazilian standards for stormwater reuse, the parameters color, turbidity, E. coli and metals were above the limits, indicating the necessity of a better treatment for solids particles and disinfection. Expanding the analysis to watershed scale, the bioretention helped to reduce NPD demands up to 45%, leading to a reduction in energy demand and carbon emission from the centralized water supply system.

Impact of karst areas on runoff generation, lateral flow and interbasin groundwater flow at the storm-event timescale

Abstract. Karst development influences the hydrological response of catchments. However, such an impact is poorly documented and even less quantified, especially over short scales of space and time. The aim of this article is thus to define karst influence on the different hydrological processes driving runoff generation, including interbasin groundwater flow (IGF) for elementary catchments at the storm-event timescale. IGFs are estimated at the scale of the river reach, by comparing inlet and outlet flows as well as the effective rainfall from the topographic elementary catchment. Three types of storm-event descriptors (characterizing water balance, hydrograph shape and lateral exchanges) were calculated for the 20 most important storm events of 108 stations in three French regions (Cévennes Mountains, Jura Mountains and Normandy), representative of different karst settings. These descriptors were compared and analysed according to catchment geology (karst, non-karst or mixed) and seasonality in order to explore the specific impact of karst areas on water balance, hydrograph shape, lateral exchanges and hydrogeological basin area. A statistical approach showed that, despite the variations with study areas, karst promotes (i) higher water infiltration from rivers during storm events, (ii) increased characteristic flood times and peak-flow attenuation, and (iii) lateral outflow. These influences are interpreted as mainly due to IGF loss that can be significant at the storm-event scale, representing around 50 % of discharge and 20 % of rainfall in the intermediate catchment. The spatial variability of such effects is also linked to contrasting lithology and karst occurrence. Our work thus provides a generic framework for assessing karst impact on the hydrological response of catchments to storm events; moreover, it can analyse flood-event characteristics in various hydro-climatic settings and can help with testing the influence of other physiographic parameters on runoff generation.

Hydrologic performance of grass swales in cold maritime climates: Impacts of frost, rain-on-snow and snow cover on flow and volume reduction

Sustainable urban drainage solutions (SuDS) are a diverse set of design options that mitigate floods and improve water quality. Grass swales are the sole component of SuDS that transports runoff over long distances to downstream recipients. A deeper understanding of the performance of grass swales in different winter conditions is important in order for cities to achieve a greater climate resiliency. The goal of this study was to assess the impacts of frequent rain-on-snow, and freeze–thaw cycles on the hydrologic performance of grass swales. A total of 63 field synthetic runoff experiments were performed in a 5.8 m long section of a grass swale in the Urriðaholt neighborhood, Gardabaer, Iceland over 18 months. A three-fold reduction in peak flow attenuation was observed in winter (avg. 13%) compared to summer (avg. 38%) for hydraulic loadings ranging between 19 and 131 cm/h. The reduction in the performance of the swale was primarily due to frost formation and secondarily due to snow. The frequent rainfall, snowmelt, and rain-on-snow events elevated the soil water content and rendered the swale media susceptible to frost formation. The formation of pore ice within the 5 cm soil horizon led to a considerable reduction in soil porosity, which negatively affected the infiltration capacity, and shortened runoff lag times. Snow affected the performance by concentrating the flow in narrow channels, which reduced the effective area of infiltration, but also led to longer lag times and stored a portion of the runoff water within its pack. Despite the deterioration in the swale’s efficiency in winter, infiltration was observed in all synthetic runoff experiments, indicating that frost was either porous/granular, or heterogeneous in nature. The swale served its purpose to moderately reduce runoff peaks and volumes, especially for small and medium events. This research highlights the importance of effectively draining infiltration-based systems in cold climates to avoid the adverse effects of low temperatures.

Dam-Break analysis: proposal of a simplified approach

ABSTRACT Simplified methods are useful alternatives for prior analysis of the effects of dam rupture and can guide the decision-making process for carrying out more complete studies. In this context, a new simplified approach is presented, which enables the analysis of aspects from dam rupture of earthen dams that failed due to overtopping, considering dam height and reservoir volume as input data. Hypothetical cases were analyzed applying dam-break hydrodynamic simulations, which results allowed the development of equations capable of estimating peak flow attenuation and peak discharge arrival time along the downstream valley. The proposed approach was applied in a hypothetical case study (15 m high dam and 17 hm3 reservoir volume), obtaining results close to those achieved through other methods, especially in case of estimating the maximum discharges throughout the downstream valley, where the average differences between the results of the methods were of the order of 15%.

A Comparison of Three Types of Permeable Pavements for Urban Runoff Mitigation in the Semi-Arid South Texas, U.S.A

This study examines the hydrologic and environmental performance of three types of permeable pavement designs: Porous Concrete Pavement (PCP), Permeable Interlocking Concrete (PICP), and Interlocking Block Pavement with Gravel (IBPG) in the semi-arid South Texas. Outflow rate, storage, Normalized Volume Reduction (NVR), Normalized Load Reductions (NLR) of Total Suspended Solids (TSS), and Biochemical Oxygen Demand (BOD5) were compared to results obtained from adjacent traditional pavements at different regional parking lots. A notable percentage of peak flow attenuation of approximately 31–100% was observed when permeable pavements were constructed and implemented. IBPG was capable to hold runoff from rainfall depths up to 136 mm prior to flooding. PCP was the most satisfactory in reducing surface runoff (NVR: 2.81 × 10−3 ± 0.67 × 10−3 m3/m2/mm), which was significantly (p < 0.05) higher (98%) than the traditional pavement. PCP was also very effective in TSS removal (NLR: 244 × 10−5 ± 143 × 10−5 kg/m2/mm), which was an increase of over 80% removal than traditional pavement. IBPG (NLR: 7.14 × 10−5 ± 7.19 × 10−5 kg/m2/mm) showed a significantly (p < 0.05) higher (46%) BOD5 removal over traditional pavement. These results demonstrate that the type of permeable pavement and the underlying media can significantly influence the runoff reduction and infiltration in this climatic region.

Quantifying peakflow attenuation/amplification in a karst river using the diffusive wave model with lateral flow

AbstractThe aim of this paper is to quantify peakflow attenuation and/or amplification in a river, investigating lateral flow from the intermediate catchment during floods. This is a challenge for the study of the hydrological response of permeable/intermittent streams, and our contribution refers to a modelling framework based on the inverse problem for the diffusive wave model applied in a karst catchment. Knowing the upstream and downstream hydrographs on a reach between two stations, we can model the lateral one, given information on the hydrological processes involved in the intermediate catchment. The model is applied to 33 flood events in the karst reach of the Iton River in French Normandy where peakflow attenuation is observed. The monitored zone consists of a succession of losing and gaining reaches controlled by strong surface‐water/groundwater (SW/GW) interactions. Our results show that despite a high baseflow increase in the reach, peakflow is attenuated. Model application shows that the intensity of lateral outflow for the flood component is linked to upstream discharge. A combination of river loss and overbank flow for highest floods is proposed for explaining the relationships. Our approach differentiates the role of outflow (river loss and overbank flow) and that of wave diffusion on peakflow attenuation. Based on several sets of model parameterization, diffusion is the main attenuation process for most cases, despite high river losses of up to several m3/s (half of peakflow for some parameterization strategies). Finally, this framework gives new insight into the SW/GW interactions during floods in karst basins, and more globally in basins characterized by disconnected river‐aquifer systems.

Performance assessment of stormwater GI practices using artificial neural networks

This study evaluates the performance of a suite of stormwater green infrastructure (GI) practices at the Belknap Campus, University of Louisville. In lack of instrumentation within individual GIs, and detailed drainage and sewer information, data mining procedures and artificial neural networks (ANN) were used. Two separate Back Propagation Neural Network Models (BPNNMs) were developed to estimate the reductions of flow volume and peak flow rates within the combined sewer system. The results from developed BPNNMs showed that following the construction of stormwater GIs at the Belknap campus, downstream wet-weather related flow decreased. The developed BPNNMs showed that the flow volume reduction and the peak flow attenuation rates had averages of approximately 33% and 61% per storm event, respectively. The flow reduction rates generally were lower for larger storms. Similarly, the peak flow rates decreased by increase of maximum intensity values per storm. However, further analysis indicated that even for large storm events, with long durations, the GIs had a positive impact on mitigation of combined sewer flows. Additionally, using rainfall data and downstream sewer flow in conjunction with artificial neural network modeling, was determined to be an effective technique for evaluating the combined hydrological performance of a suite of stormwater GIs.

Effects of slopes on the stormwater attenuation performance in extensive green roof

This study is aimed to determine the effects of slope on stormwater retention and peak flow attenuation performances in extensive green roof in Malaysia. One green roof test bed with dimensions of 2.0 m (length) x 1 m (width) x 0.2 m (height) was constructed in Universiti Tenaga Nasional. The substrate layer was fixed as 130 mm depth and placed on top of the filter fabric and drainage layers. The green roof test bed was planted with Portulaca Grandiflora (sedum species) as the native plant in Malaysia. Different slopes (0 º, 2 º, 5 º and 7 º) of green roof test bed were tested in this study for its stormwater retention and peak flow attenuation performances. The results show that stormwater retention percentages are ranged from 56.9% to 52.3%. The stormwater retention percentages are decreased as slope increased in this study. Flat slope showed the longest observed time of peak flow while the 7 º slope has the shortest observed time of peak flow. This finding suggests that slope has a significant impact to the stormwater retention and peak flow attenuation performances in extensive green roof.

Urban stormwater treatment by a constructed wetland: Seasonality impacts on hydraulic efficiency, physico-chemical behavior and heavy metal occurrence

Urban stormwater affects the general quality of water bodies because of their hydraulic and pollution impacts. Stormwater discharges modify stream water flow and are reported as major source of heavy metals (HMs) in urban streams. Stormwater Constructed Wetlands (SCWs) have been built worldwide to manage stormwater before it is released into hydrosystems. In SCWs, stormwater is stored, evaporated and sometimes infiltrated. Subsequently, the HMs in stormwater can be settled, filtered and bioassimilated by microorganisms. Hence, the efficiency of SCWs in managing stormwater depends on climatic conditions, which change with season. The aim of this study was to investigate the impacts of seasonality on the performance of a 6-year-old constructed wetland made with a pond followed by a vertical flow filter. Hydraulic performance of, physico-chemical behaviour of, and HM mitigation via the SCW were evaluated using over 3 years of monitoring (2015–2017) data. Only 35% of the rain events that occurred in the studied catchment caused a discharge into the pond and 17% into the filter. The SCW was mostly supplied with stormwater in spring and summer and provided peak flow attenuation from 97 to 100% in all seasons. Variations in physico-chemical parameters (temperature, dissolved oxygen, pH, and redox potential) were caused by seasonal and dry/wet weather changes. They were greater in the pond than in the filter, which buffers these variations. The high physico-chemical variations in the pond probably had a deleterious effect on HM storage in the pond sediments. Finally, hydrologic and physico-chemical conditions (antecedent dry period length, pH, redox potential) affected the HM concentrations along the SCW. However, HM removal efficiencies were >97% in all seasons.

Assessment of the Flow at the Chatara on Koshi River Basin using Semi Distributed Model

Hydrological modeling is a physical phenomenon to incorporate rainfall-runoff process in watershed area at particular point and analysis the behaviors of the flow through outlet. There are various types of models such as black box, conceptual and physical based model depends upon the availability of required data, parameters and description of the physical process. Semi distributed model is a conceptual and physical based model which has been developed to bridge the gap between the lumped and distributed model. It have more advantages than other models with respect to time of calculation, less number of parameters, comparatively low calibration needs and have high efficiency of model. The model performance may be achieved upon the qualitative and quantitative available rainfall data, land use data and size of the watershed. In this study, Koshi river basin was taken for the study area. Kinematic wave method was used for overland routing and Muskingum conge method was applied for channel routing to describe the discharge on Saptakoshi river and peak flow attenuation and dispersion observed in the direct runoff hydrograph. From this study result, Annual runoff, Peak flow and time of peak at the outlet are similar to the observed flow in calibration and verification period using trapezoidal channel. The nash efficiency obtained from the semi distributed model with kinematic wave method is more than 90%in verification periods and nearly 90% in calibration periods Hence Hydrological modeling is a powerful technique in the planning and development of integrated approach for management of water resources.Journal of the Institute of Engineering, 2016, 12(1): 184-198

Evaluating functions of reservoirs′ storage capacities and locations on daily peak attenuation for Ganjiang River Basin using Xinanjiang model

Flooding is the most prevalent and costly natural disaster in the world and building reservoirs is one of the major structural measures for flood control and management. In this paper, a framework was proposed to evaluate functions of reservoirs′ locations and magnitudes on daily peak flow attenuation for a large basin of China, namely Ganjiang River Basin. In this study, the Xinanjiang model was adopted to simulate inflows of the reservoirs and flood hydrographs of all sub-catchments of the basin, and simple reservoir operation rules were established for calculating outflows of the reservoirs. Four reservoirs scenarios were established to analyze reservoirs′ locations on daily peak flow attenuation. The results showed that: 1) reservoirs attenuated the peak discharges for all simulated floods, when the flood storage capacities increase as new reservoirs were built, the peak discharge attenuation by reservoirs showed an increasing tendency both in absolute and relative measures; 2) reservoirs attenuated more peak discharge relatively for small floods than for large ones; 3) reservoirs reduced the peak discharge more efficiently for the floods with single peak or multi peaks with main peak occurred first; and 4) effect of upstream reservoirs on peak attenuation decreased from upper reaches to lower reaches; upstream and midstream reservoirs played important roles in decreasing peak discharge both at middle and lower reaches, and downstream reservoirs had less effect on large peak discharge attenuation at outlet of the basin. The proposed framework of evaluating functions of multiple reservoirs′ storage capacities and locations on peak attenuation is valuable for flood control planning and management at basin scale.

Effectiveness of BIOECODS for peak flow attenuation: an appraisal using InfoWorks SD

ABSTRACTThe Bio-Ecological Drainage System (BIOECODS) is a sustainable drainage system, which adopts a “control at source” approach for urban storm water management in Malaysia. This study attempts to model a small-scale BIOECODS using InfoWorks SD. New modelling techniques are used to fully integrate the surface and on-line subsurface conveyance system, in which overland flow routing is described by a storm water management model that uses a nonlinear reservoir method and the kinematic wave approximation of the St Venant equation, and subsurface flow is described by the Horton method in conjunction with the Soil Conservation Service (SCS) curve number (CN) method. The observed water levels at primary outlets are compared with those obtained from model simulation. The modelling approach has been proven successful as the hydrographs (predicted and observed) match each other closely, with a mean error in the range of 4.58–7.32%. Results from the model showed that the BIOECODS is able to attenuate peak flow by 60–75%, and increase the lag time by 20 min within an area of <28 300 m2 when compared with a traditional drainage system.

Modelling green roof stormwater response for different soil depths

Green roofs have been proposed as a way to mitigate stormwater run-off in urban areas due to the possibility of retrofit to existing buildings. The amount of run-off is influenced by the, humidity, evapotranspiration, as well as soil type and depth. A modelling approach was undertaken to evaluate the response of different soil depths to cumulative rainfall and the efficiency in stormwater flow rate attenuation. The soil hydraulics were modelled using HYDRUS-1D software developed for modelling water flow in variably saturated porous media. Model runs were carried out for three quarterly scenarios to determine run-off peak flow rates and the overall retention, based on evapotranspiration rates of succulent plants and rainfall registers from Auckland, New Zealand. The soil depths modelled ranged from 5 to 160cm. The efficiencies in peak flow attenuation by the shallowest soil considered were reduced under extreme and longer rainfall events by 3%. Therefore shallow soil or extensive green roofs may, on a wide scale, overcome the performance of deep soils due to their lighter weight which adds limited loads to existing roof structures thereby making them suited to retrofit greater numbers of buildings.

Flow routing with Semi-distributed hydrological model HEC- HMS in case of Narayani River Basin

Routing is the modeling process to determine the outflow at an outlet from given inflow at upstream of the channel. A hydrological simulation model use mathematical equations that establish relationships between inputs and outputs of water system and simulates the catchment response to the rainfall input. Several hydrological models have been developed to assist in understanding of hydrologic system and water resources management. A model, once calibrated and verified on catchments, provides a multi-purpose tool for further analysis. Semi-Distributed models in hydrology are usually physically based in that they are defined in terms of theoretically acceptable continuum equations. They do, however, involve some degree of lumping since analytical solutions to the equations cannot be found, and so approximate numerical solutions, based on a finite difference or finite element discretization of the space and time dimensions, are implemented. Many rivers in Nepal are either ungauged or poorly gauged due to extreme complex terrains, monsoon climate and lack of technical and financial supports. In this context the role of hydrological models are extremely useful. In practical applications, hydrological routing methods are relatively simple to implement reasonably accurate. In this study, Gandaki river basin was taken for the study area. Kinematic wave method was used for overland routing and Muskingum cunge method was applied for channel routing to describe the discharge on Narayani river and peak flow attenuation and dispersion observed in the direct runoff hydrograph. Channel cross section parameters are extracted using HEC- GeoRAS extension tool of GIS. From this study result, Annual runoff, Peak flow and time of peak at the outlet are similar to the observed flow in calibration and verification period using trapezoidal channel. Hence Hydrological modeling is a powerful technique in the planning and development of integrated approach for management of water resources. DOI: http://dx.doi.org/10.3126/jie.v10i1.10877Journal of the Institute of Engineering, Vol. 10, No. 1, 2014 pp. 45-58

Riparian responses to reduced flood flows: comparing and contrasting narrowleaf and broadleaf cottonwoods

To enable assessment of risks of water management to riparian ecosystems at a regional scale, we developed a quantile-regression model of abundance of broadleaf cottonwoods (Populus deltoides and P. fremontii) as a function of flood flow attenuation. To test whether this model was transferrable to narrowleaf cottonwood (Populus angustifolia), we measured narrowleaf abundance along 39 river reaches in northwestern Colorado, USA. The model performed well for narrowleaf in all 32 reaches where reservoir storage was <75% of mean annual flow. Field data did not fit the model at four of seven reaches where reservoir storage was >90% of mean annual flow. In these four reaches, narrowleaf was abundant despite peak flow attenuation of 45–61%. Poor model performance in these four reaches may be explained in part by a pulse of narrowleaf cottonwood expansion as a response to channel narrowing and in part by differences between narrowleaf and broadleaf cottonwood response to floods and drought.Editor Z.W. Kundzewicz; Guest editor M. AcremanCitation Wilding, T.K., Sanderson, J.S., Merritt, D.M., Rood, S.B., and Poff, N.L., 2014. Riparian responses to reduced flood flows: comparing and contrasting narrowleaf and broadleaf cottonwoods. Hydrological Sciences Journal, 59 (3–4), 605–617.

Climate change adaptation of urban water management systems in the wet/dry tropics

Climate change impacts in the wet/dry tropics are expected to include an increase in extreme daily rainfall events, mean evaporation rates and mean temperatures. The proposed Weddell development, located 40 km south of Darwin, is forecast to have up to 10,500 residents by 2021. This increasing population coupled with projected climate change impacts will increase demand for potable water and exacerbate existing problems associated with the region’s wastewater treatment infrastructure. Water sensitive urban design (WSUD) provides an effective method of improving discharge water quality, providing water storage capacity and achieving peak flow attenuation. Using the Weddell development as a point of reference this study has shown that WSUD designs implemented in sub-tropical and temperate areas are not directly transposable to the wet/dry tropics. WSUD designs need to be adapted to cope with the extended dry period characteristic of the wet/dry tropics. While WSUD elements could constitute effective adaptation measures in the wet/dry tropics, there is a definite need for long-term studies that assess the practicality of maintaining functioning WSUD elements in the region. In this contribution we discuss the key issues associated with WSUD in the Northern Territory and the outcomes of a consultation workshop with government agencies.

Catch and Release Strategies: Using Available in-Plant Storage for Wastewater Peak Flow Attenuation

Catch and Release Strategies: Using Available in-Plant Storage for Wastewater Peak Flow AttenuationThe City of Los Angeles' Bureau of Sanitation provides wastewater collection, treatment, and disposal services for approximately 4 million residents within a 600-square-mile service area, including 29 contract agencies outside the City. The City's more than 6,700 miles of public sewers that can convey about 500 million gallons per day (MGD) of flow to the City's four wastewater treatment and water...Author(s)Fernando F. GonzalezDavid MoeringRegidia MayrenaRowena LauAli PoostiAdel HagekhalilSourceProceedings of the Water Environment FederationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jun, 2013ISSN1938-6478DOI10.2175/193864713813504421Volume / Issue2013 / 1Content sourceCollection Systems ConferenceCopyright2013Word count874

Constructed Wetlands for Management of Urban Stormwater Runoff

In urban and suburban areas, stormwater runoff has been identified as a significant contributor to water quality impairment. The quality of the stormwater and the characteristics of the pollutants present are dependent on the types of surfaces the stormwater encounters. The scientific research within this field has been focused on pollutants such as nutrients, heavy metals, organic and particulate matter, herbicides, and polycyclic aromatic hydrocarbons. These constituents may pose risks to life forms along with technical and aesthetic problems and thus require implementation of management practices for mitigating stormwater pollution. Structural best management practices are now commonplace for stormwater management in urban developments and range from simple filter strips, to the latest green technology methods such as constructed wetlands. Physicochemical and biological properties of wetlands provide many positive attributes for remediating contaminants. Specifically, wetland stormwater treatment areas offer the advantages of water storage and peak-flow attenuation, nutrient cycling and burial, metal sequestration, sediment settling, and breakdown of organic compounds along with certain ancillary benefits such as recreational facilities as well as functioning as a wildlife habitat. In this context, the authors summarize information on stormwater and different structural best management practices used for stormwater treatment. They critically examine the potential of constructed wetlands for stormwater treatment by looking at the present research initiatives toward execution of this technology. Future considerations in choosing constructed wetlands as stormwater treatment systems are also highlighted by discussing benefits and inadequacies as well as economic facets of constructed wetlands.