Stormwater Detention Research Articles

Relationship Between Woody Plant Colonization and Typha L. Encroachment in Stormwater Detention Basins

We studied stormwater detention basins where woody vegetation removal was suspended for 2 years in Virginia, USA to determine if woody vegetation can control Typha populations and how early woody plant succession interacts with Typha, other herbaceous vegetation, and site factors. Distribution and composition of woody vegetation, Typha and non-Typha herbaceous vegetation biomass, and site factors were assessed at 100 plots in four basins ranging in age from 7 to 17 years. A greenhouse study examined the interaction of shade and soil moisture on Typha biomass and persistence. Principal component analysis identified an environmental gradient associated with greater water table depths and decreased elevation that favored Typha but negatively influenced woody vegetation. Elevation was correlated with litter layer distribution, suggesting that initial topography influences subsequent environmental characteristics and thus plant communities. Soil organic matter at 0-10 cm ranged from 5.4 to 12.7%. Woody plants present were native species with the exception of Ailanthus altissima and Pyrus calleryana. In the greenhouse, shade and reduced soil moisture decreased Typha biomass and rhizome length. The shade effect was strongest in flooded plants and the soil moisture effect was strongest for plants in full sun. Typha in dry soil and heavy shade had 95% less total biomass and 83% smaller rhizomes than Typha in flooded soil and full sun, but even moderate soil moisture reductions decreased above- and below-ground biomass by 63 and 56%, respectively. Suspending maintenance allows restoration of woody vegetation dominated by native species and may suppress Typha invasion.

Improving the performance of stormwater detention basins by real-time control using rainfall forecasts

Dry detention ponds are commonly implemented to mitigate the impacts of urban runoff on receiving water bodies. They currently rely on static control through a fixed limitation of their maximum outflow rate. Real-Time Control (RTC) allows optimizing their performance by manipulation of an outlet valve. This study developed several enhanced RTC scenarios of a dry detention pond located at the outlet of a small urban catchment near Québec City, Canada. The catchment's runoff quantity and TSS concentration were simulated by a SWMM5 model with an improved wash-off formulation. The control procedures rely on rainfall detection, on measures of the pond's water height, and in some of the RTC scenarios on rainfall forecasts. The implemented RTC strategies allow a substantial improvement of the pond's performance - the TSS removal efficiency increases from 46% (current state) to about 90% - while remaining safe and taking a mosquito-breeding risk constraint into account.

Multi-objective optimal layout of distributed storm-water detention

The determination of locations and sizes for such a system is important in a drainage master plan or a storm-water management system. However, the distribution of detentions in the upstream and midstream is often more dispersed using many combinations of volume scales. This paper uses the non-dominated sorting genetic algorithm combined with the Storm Water Management Model to explore and calculate the optimal layout scheme for decentralized rainwater detention. The purpose is to find a design and planning method that can achieve the optimal balance of decentralized detention considering the aspects of flood disaster control, peak flow reduction, and investment cost. The optimal results of Pareto in applied case show that among the five most unfavourable nodes, the detentions with different layout volumes and relatively smaller size can control water logging from rainstorm. The project cost is effectively reduced and the standard of the return period of the regional rainwater system is enhanced from 2 to 20 years.

Discharge Coefficients for Orifices Cut into Round Pipes

AbstractThis study focuses on the discharge coefficient (Cd) for flow into orifices cut with a circular bit perpendicular to and along the centerline of a round pipe, a common configuration on perforated risers installed as the principal outlets for stormwater detention or sediment basins. When predicting flow, the orifice area is generally defined as the area of the bit used to cut the hole, but the true orifice area is larger than the bit due to the curvature of the riser pipe. Four different descriptions for orifice area were tested while attempting to fit Cd to measured discharge experiments. The tests showed that Cd decreases as the orifice diameter approaches the diameter of the riser. Photographic imagery shows that the reduced Cd is due to lateral flow from the riser’s curved sides decreasing the vena contracta area more than what normally occurs during flow through an orifice in a flat plate. In contrast, but to a lesser extent, Cd increases as the water surface approaches the top of the orifice....

Storm water management: Potential for lower cost and more benefits if farmers and municipalities cooperate on tile drainage

THE PROBLEM AND CURRENT COSTS OF ITS SOLUTION When water tables rise to the surface, additional rain runs off. Since an inch of runoff from a 4,000 ha (10,000 ac) watershed amounts to 1,027,290 m3 (36,300,000 ft3) of water, such runoff becomes an engine of flooding and destruction if it comes off quickly. Attractive stream frontage becomes a menace when the stream's turbulent surface rises 3 or 4 m (10 or 13 ft), floods basements, and pushes buildings off their foundations. Following such “once in a hundred year” events, diligent municipal managers commonly evaluate the damages and seek solutions that can prevent such damage in the future. The common solution is to construct one or more stormwater detention basins between the source of the runoff water and the area where the runoff water will do the most damage. Water detained in such basins is released at rates which will not cause significant damage downstream, but will empty the basin to restore its detention capacity within a few days, as indicated by the red line in figure 1. Costs of buying the land for and constructing such stormwater detention basins have ranged from about US$18 to US$35 m-3…

Optimum combination of pond volume and outlet capacity of a stormwater detention pond using particle swarm optimization

Detention ponds are best management practices designed for the treatment and control of urban stormwater. Their design objectives are mainly to control the quantity and quality of urban stormwater at the minimum cost. However, tradeoff exists between these objectives and this call for optimization. Long term hourly rainfall data were analyzed and the rainfall characteristics were obtained. Analytical Probabilistic Models (APM) were employed and the model parameters were derived from the closest stations to the study areas. The APM parameters, along with catchment parameters, were used to develop optimal combination of pond volume and outflow that yield the minimum cost using the APM and Particle Swarm Optimization (PSO). Comparison of the PSO with APM shows that the PSO result is more accurate as it does not need discretization of outlet size. The PSO model was also found to be more robust, computationally cheaper and faster to implement.

Complex baseflow in urban streams: an example from central Ohio, USA

Baseflow in urban streams remains an under-researched topic, given the critical roles it plays and the extensive and ever-increasing pace of urbanization and its impacts on stream ecosystems. This study is designed to characterize the complexity of baseflow in Dry Run, an urban stream in Columbus, Ohio. A hierarchical modeling approach combined with observations of streamflow discharge (Q) and specific conductance (SC) of the stream water was applied. The streamflow measurements showed that baseflow in Dry Run is small (below 1 m3 s−1) and being impacted by anthropogenic activities that directly discharge water into the stream. Model analyses using IHACRES and SWMM showed that baseflow is mainly composed of two different components—groundwater inflow and slowly released flows from storm-water detention ponds. The complex origins of baseflow are exemplified by hysteresis, which can be described with a plot of SC versus discharge. Overall, the study shows the value of geochemical measurements that constrain conceptual models of source-water inflows to the stream.

Assessment of a countywide stormwater pond improvement program

Numerous approaches have been advocated to improve pollutant removal in stormwater retention and detention ponds. The Hillsborough County (FL) Adopt-A-Pond program is one such application. However, ex post evaluation of these approaches is particularly limited. Water quality and vegetative characteristics were assessed at participating Adopt-A-Pond sites to explore potential impacts of the program on measurable environmental parameters. Statistical analysis of the results failed to demonstrate significant environmental improvements associated with the Adopt-A-Pond program, and measures of program activity did not illustrate a consistently positive influence. These results illustrate the need for ex post evaluations and indicate a general need to readdress the policies and implementation of the program. Poor compliance by program volunteers, evident by the limited span of group participation (mean = 2.5 years) and relatively low percentage of actively involved residents, is a possible culprit, as the efficacy of pond enhancement techniques is firmly established in the literature.

Performances of Two Macrophytes Species in Floating Treatment Wetlands for Cadmium, Nickel, and Zinc Removal from Urban Stormwater Runoff

Conventional stormwater detention ponds frequently show limitations for dissolved heavy metal removal. Floating treatment wetlands (FTWs), a variant of constructed wetlands, are considered as a promising technology to improve the quality of urban stormwater runoff. Our study aimed at evaluating the treatment performances of FTWs for cadmium, nickel, and zinc removal through a pot experiment. Two macrophytes species, Juncus effusus and Carex riparia, were grown during 4 months under three metal concentrations (in micrograms per liter): high (Cd, 200; Ni, 500; Zn, 2,000), low (Cd, 10; Ni, 10; Zn, 40), and control (Cd–Ni–Zn, 0). Results showed that both macrophytes species significantly removed dissolved heavy metals. Cadmium and nickel accumulations were greater in roots than in shoots for both species. Under low metal concentration, maximum accumulation of 0.4 μg g−1 dry weight (DW) for Cd was observed in the roots of J. effusus. Under high metal concentration, accumulations of up to 5 μg Cd g−1 DW and 62 μg Ni g−1 DW were observed in the roots of J. effusus and up to 73 μg Zn g−1 DW in the roots of C. riparia. Although J. effusus and C. riparia are not recognized as metal hyperaccumulators, our study demonstrated that they can achieve high metal uptake when both roots and shoots are harvested.

Stormwater Pond Sediment Loading and Accumulation Analysis Using Continuous Simulation

Stormwater Pond Sediment Loading and Accumulation Analysis Using Continuous SimulationThe permanent pool in stormwater detention facilities is designed for water quality treatment by providing an appropriate storage volume for the settling of suspended solids and particulate matter that is carried in stormwater runoff. Sizing of the permanent pool volume is often based on local regulatory requirements that dictate a prescribed Total Suspended Solids (TSS) removal rate, expressed as...Author(s)Mike GregorySourceProceedings of the Water Environment FederationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Oct, 2013ISSN1938-6478DOI10.2175/193864713813668169Volume / Issue2013 / 18Content sourceWEFTECCopyright2013Word count167

Evaluation of multi-use stormwater detention basins for improved urban watershed management

Detention basins are used to capture postdevelopment runoff and control the peak discharge of the outflow using orifices and weirs. The use of detention basins is typical practice in the construction of new developments on the fringe of existing urban areas, such as the Ulsan–Hwabong district in the city of Ulsan, South Korea. In this study, the required volume and flooding area of a detention basin was determined to control development outflow peaks for 2-year, 10-year, and 100-year design storms with type II rainfall distributions as characterized by the US Department of Agriculture's Soil Conservation Service method. The rainfall–runoff simulation model used was the US Environmental Protection Agency's Storm Water Management Model (EPA-SWMM) 5, which is the latest version of the software, updated for Windows. We designed three cases of detention basins multi-staged by 2-year, 10-year, and 100-year design storms and verified the designs with the application of 49 years (1961–2009) of hourly historical rainfall data. The three detention basin designs were compared in terms of the total construction and land costs as well as the benefits associated with recreational facilities or parking lot use. As a result, the design sizes of the detention basins are slightly greater than the actual sizes needed based on the historical rainfall application. Multi-use detention basins (MDBs) based on 2-year and 10-year design storms were found to yield 37.4% and 22.8% benefits, respectively, for recreational facility use compared with detention basins without multi-use space, and the results also indicate that benefits accrue after 6.5 years for parking lot use. The results of this study suggest that an MDB based on a 2-year design storm is the most cost-effective design among the three cases considered for Ulsan, South Korea. Copyright © 2012 John Wiley & Sons, Ltd.

Detention Pond Sediment Accumulation Prediction using Monte Carlo Simulation

Problem statement: A study in Malaysia had been carried out to predic t the sediment accumulation in urban detention ponds. Suspended sediment is pollutant of primary concern to the river that results in adverse environmental effect. Detention pond becomes a practical approach to thi s problem. Suspended sediment that settled in stormwater detention pond, can bring effect to the detention pond functions. Questions were raised on how certain were the observed and predicted values of sediment depth and load accumulation esti mations. Secondly the question was what the sediment accumulation be in the next 100 years. The uncertainties of sediments estimation vary greatly due to the hydrological variability and rainfall ra ndom nature obtain the relationship between flow discharge and suspended sediment rate using on-site data collection at UTM and Ledang Heights, Nusajaya. Predict accumulated sediment loads and depth from MUSLE over 10-100 years. Analyze the uncertainties of sediment loads and depth using Monte Carlo Simulation (MCS) combining normal distribution. Obtain the maximum probability of occ urrence of sediment loads and depth in the detention pond. Approach: Modified Universal Soil Loss Equation (MUSLE) and Trap Efficiency (TE) Method was applied to predict sediment accumulation. This uncertainty of sediment loads and depth was carried out using Monte Carlo Simulation (MCS) Method. The water samples were collected for suspended solids data and other water quality parameters at Ledang Heights, Nusajaya, Johor and University Technology Malaysia (UTM), Johor. Sampling station were randomly selected at the inlet and outlet of the detention pond. The hydrological parameters such as flow and velocity were also collected. Results: The simulation results showed the maximum probability of occurrence value for observed sediment loads and sediment dept h from Ledang Heights were 0.0062 tons (16.5%) and 0.0005 mm (17.5%) respectively. The maximum probability of occurrence values for observed sediment loads and sediment depth at UTM showed no obvious differences with Ledang Heights; about 0.015 tons (16.8%) and 0.00037 mm (15.5%) respectively. The maximum occurrence of predicted sediment loads and sediment depth usin g MUSLE method for Ledang Height was 77.8 tons (16.8%) and 7.5 mm (26.8%) respectively. The maximum occurrence for UTM was slightly higher, about 264 tons (15.70%) and 7.0 mm (21.10%) respectively. The higher values for UTM were suspected due to its larger watershed. The sediment loads and depths were also predicted for the next 50-100 years considering no significant watershed l and use changes. Conclusion: The sediment accumulation estimation and forecasting are very important to ensure the effectiveness and proper operation of the detention pond. The continuous eff ort through natural sediment control measures such as proper vegetation and grass inplants are always encourage around the detention pond and surrounding areas throughout its lifespan.

Stormwater detention basin for improving road-runoff quality

Both wet and dry detention basins are commonly used for the treatment of road runoff. The basin investigated in this study was located on the eastern side of the southern expressway in Adelaide, Australia. Event mean pollutant concentrations (EMCs) and total pollutant loads were determined for the basin inflows and outflows. The water quality parameters tested included pH, conductivity, total suspended solids, total dissolved solids (TDS), total Kjeldahl nitrogen, total phosphorous, total hydrocarbons, cadmium, chromium, copper, lead, zinc and nickel. Six critical events were sampled in this manner during the course of the investigation. Total pollutant loads passing through as basin inflow were determined over the six monitored events. Comparison of basin inflow and outflow quality demonstrated that the average load reductions varied from as little as 18% for TDS up to 77% for total phosphorous and lead. While copper concentrations at the basin inflow were detected in four out of the six events, no detectable concentrations were found in the outflows. The average reductions for lead and zinc were more than 50% on more than 80% of occasions.

New Method for Modeling Thin-Walled Orifice Flow under Partially Submerged Conditions

AbstractOrifices are often used in stormwater detention facilities for reducing runoff peak flow and achieving extended detention times to improve water quality. Orifices often flow partially full; therefore, accurate and easily implemented methods of modeling basin outflow under such conditions are needed. In this paper we describe two models of partially submerged flow in thin-walled orifices and conduct full-scale testing of these models. The best model (termed the top-width weir approach) treats the orifice as an equivalently sized rectangular weir, where the equivalent weir length equals the top width of flow in the orifice until half-full and the diameter of the orifice when greater than half-full. A single fitting coefficient Cw is required, which is directly proportional to the discharge coefficient for submerged orifice flow. This method provides results that, except for low submergence conditions, are within 2 to 5% of experimental data for steady flow, a significant improvement over the existin...

Identification and Induction of Human, Social, and Cultural Capitals through an Experimental Approach to Stormwater Management

Decentralized stormwater management is based on the dispersal of stormwater management practices (SWMP) throughout a watershed to manage stormwater runoff volume and potentially restore natural hydrologic processes. This approach to stormwater management is increasingly popular but faces constraints related to land access and citizen engagement. We tested a novel method of environmental management through citizen-based stormwater management on suburban private land. After a nominal induction of human capital through an education campaign, two successive (2007, 2008) reverse auctions engaged residents to voluntarily bid on installation of SWMPs on their property. Cumulatively, 81 rain gardens and 165 rain barrels were installed on approximately one-third of the 350 eligible residential properties in the watershed, resulting in an estimated 360 m3 increase in stormwater detention capacity. One surprising result was the abundance of zero dollar bids, indicating even a limited-effort human capital campaign was sufficient to enroll many participants. In addition, we used statistical methods to illustrate the significant role of social capital in forming clusters of adjacent properties that participated in bidding. This indicated that as participants shared their experiences, neighbors may have become more willing to trust the program and enroll. Significant agglomerations of participating properties may indicate a shift in neighborhood culture regarding stormwater management with positive implications for watershed health through the sustained induction of alternate capitals.

Assessing biological and chemical signatures related to nutrient removal by floating islands in stormwater mesocosms

Aquatic floating plants on BioHaven mats were tested for their potential use as a Best Management Practice to be incorporated within existing stormwater detention ponds. Plants were analyzed for their capability to remove nutrient-pollution in parallel with the study of ecological dynamics. Experiments were carried out in cylindrical mesocosms of 5m diameter and 1.2m height, above-ground pools with a water volume of 14m3. The design parameters tested were for 5% and 10% vegetated floating island coverage of the mesocosm, both with and without shoreline plants called littoral zone. This littoral shelf was 0.5m thick, graded at a downward slope of 1:5 toward the center using loamy soil with low organic matter content, excavated from below turf grass. Endemic plant species were chosen for the experimental location in central Florida based on a wetland identification manual by the Florida Department of Environmental Protection to ensure the study was not compromised by unique climate requirements of the plants. Nutrient and aquatic chemical conditions such as pH, dissolved oxygen, temperature, turbidity, and chlorophyll a were monitored to understand their relationships to the general wetland ecosystem. Real-time polymerase chain reaction analysis identified the microbial activity near the rhizospheric zone. Logistical placement considerations were made using spatial sampling across the horizontal plane of the mesocosms, beneath and around the root zone, to determine if nutrients tend to aggregate around the floating island. This study concluded that the application of floating islands as a stormwater technology can remove nutrients through plant uptake and biological activity. The most cost-effective size in the outdoor mesocosms was 5% surface area coverage of the mat.

Optimal design of stormwater detention basin using the genetic algorithm

The urbanization of an undeveloped area often shortens outflow travel time and increases peak discharge from the basin, thereby increasing the downstream flood frequency. Stormwater detention ponds are the most common measure to maintain the outflow from the post-developed basin to a flow similar to that under the pre-developed condition. The design criteria of stormwater detention ponds are to minimize construction cost while achieving the flood control purpose. The tedious and time-consuming, trial-and-error method is commonly used to determine the optimal size and location of the pond and outlet structure for a design storm period. In this study, a stochastic search algorithm, a Genetic Algorithm (GA), is used to optimize the detention pond design. The decision variables are the pond storage, and the pipe diameters and number of pipes for the service outlet. The flood control objective considered in this study is that the peak discharge in the post-developed condition does not exceed that under the pre-developed condition and that the maximum water level in the pond during the flood remains below the allowable water level. The proposed optimization algorithm method was applied to the real design of two detention ponds in South Korea, where it generated better design options comprising smaller pond storage and smaller outlet standpipe dimensions than those of the traditional trial-and-error method, and in a much shorter computational time. Therefore, the stochastic search algorithm, GA, can be successfully applied in the design of a stormwater detention basin to improve accuracy and convenience. The engineers can accordingly assess the development plan in terms of the potential basin disaster more efficiently than is possible when using the tedious computation method.

Hydroclimatology of flash flooding in Atlanta

The objective of this study is to characterize the climatology of extreme rainfall and flash flooding in Atlanta, Georgia using high‐resolution land surface, rainfall, and discharge datasets. We examine nine urban watersheds in the Atlanta area that range in size from 3.7 to 225 km2 and exhibit a range of urban development and land‐use characteristics. We develop a high‐resolution 15 min, 1 km2 radar rainfall data set for the 2002–2010 period using the Hydro‐NEXRAD system with volume scan reflectivity observations from the Atlanta WSR‐88D radar and rainfall observations from a dense network of 72 U.S. Geological Survey rain gauges. Bias‐corrected radar rainfall fields accurately capture the spatial and temporal structure of heavy rainfall. There is enhancement of heavy rainfall within and east of the urban core, and a rainfall minimum north and northwest of the city. There has been an increase in variability of annual flood peaks in Atlanta since the 1960s associated with urban impacts on runoff production. Flood response is dependent on a combination of basin size, drainage network structure, spatial distribution of land use, and basin storage in urban soils and storm water detention ponds. Future studies of urban rainfall modification in Atlanta and elsewhere should consider the influence of regional topography and other geographic features on the storm environment.

Ameliorative effects of sodium chloride on acute copper toxicity among Cope's gray tree frog (Hyla chrysoscelis) and green frog (Rana clamitans) embryos

Urban stormwater runoff is composed of a mixture of components, including polycyclic aromatic hydrocarbons, metals, deicing agents, and many others. The fate of these chemicals is often in stormwater detention ponds that are used by amphibians for breeding. Among aquatic organisms, the toxic mechanism for many metals involves interference with active Na(+) and Cl(-) uptake. Addition of cations has been shown to reduce the toxicity of metals among some aquatic organisms through competitive inhibition, but no studies have investigated the interaction between NaCl and Cu among amphibian embryos and larvae. To determine the degree to which NaCl may ameliorate the toxicity of Cu to amphibian embryos and larvae, the authors exposed Hyla chrysoscelis (Cope's gray treefrogs) and Rana (Lithobates) clamitans (green frogs) to seven levels of Cu and NaCl in fully factorial experiments. When exposure was in artificial hard water, Cu was highly toxic to both species (96-h median lethal concentration [LC50] of 44.7 µg/L and 162.6 µg/L for H. chrysoscelis and R. clamitans, respectively). However, approximately 500 mg/L of NaCl eliminated Cu toxicity over the range of Cu concentrations used in the experiments (maximum 150 µg Cu/L for H. chrysoscelis and 325 µg Cu/L for R. clamitans). The current results suggest that NaCl is likely responsible for the toxic effects of NaCl and metal mixtures that might be typical of runoff from road surfaces in northern latitudes.

Performance of stormwater detention tanks for urban drainage systems in northern Italy

The performance of stormwater detention tanks with alternative design configurations (insertion in the storm sewer network; volume per impervious hectare) and operating conditions (continuous and intermittent emptying rules) have been evaluated according to an integrated approach. Various performance indices have been adopted to describe the mitigation of the pollution impact to the natural environment, the reduction of the management and maintenance charges for the urban drainage system, the preservation of the normal purification efficiency, and the limitation of the costs at the treatment plant. The US EPA Storm Water Management Model has been used to simulate the rainfall-runoff process and the pollutant dynamics on theoretical catchments and storm sewer networks for an individual event, as well as for a continuous run of events and inter event periods of one year recorded at the rain gauge of Cascina Scala (Pavia, northern Italy). Also the influence of the main characteristics of the urban catchment and the drainage system (area of the catchment and slope of the network) on the performance of alternative design and operating solutions has been examined. Stormwater detention tanks combined with flow regulators demonstrated good performance with respect to environmental pollution: satisfactory performance indicators can be obtained with fairly low flow rates of flow regulators (0.5-1L/s per hectare of impervious area) and tank volumes of about 35-50m(3) per impervious hectare. Continuous emptying guaranteed the lowest number and duration of overflows, while an intermittent operation minimised the volume sent for purification reducing the costs and the risks of impairment in the normal treatment efficiency of the plant. Overall, simulation outcomes revealed that the performance indexes are scarcely affected by the area of the catchment and the slope of the drainage network. Theresult of this study represents a key issue for the implementation of environmental policies in large urban areas.