Till följd av klimatförändringar förväntas mer intensiva nederbördsmönster i framtiden. Dagvattenhantering är en essentiell del i urbana miljöer för att motverka översvämningar vid stora vattenflöden. Grön infrastruktur bidrar till dagvattenhanteringen genom dess ekosystemtjänst dagvatten- och flödesreglering. I uppsatsen undersöks ekosystemtjänstens kvantitativa potential att fånga upp vatten under ett 10-årsregn med varaktigheten en timme, med syftet att få en approximativ bild av grön infrastrukturs potentiella bidrag till dagvattenhanteringen i Stockholms innerstad. Studien är baserad på beräkningar i ArcGIS genom att försöka kvantifiera den gröna infrastrukturens bidragande parametrar till ekosystemtjänsten dagvatten- och flödesreglering. Resultatet av studien visade att dagens gröna infrastruktur har potential att ta hand om 26 % av ett 10-årsregn med varaktighet en timme, motsvarande siffra för nederbördsprojektioner för ett 10-årsregn år 2100 var 21 %. Uppsatsen redogör även för klimatförändringarnas påverkan på ekosystemtjänsten. / As a consequence of global warming, future precipitation patterns are predicted to be more intense. Thus, stormwater treatment plays an essential role in the urban environment to prevent flooding. Green infrastructure contributes to the treatment of stormwater through its ecosystem service “Stormwater treatment and flow regulation”. The objective of this study was to quantify the capacity of this ecosystem service by the use of Geographical Information Systems (GIS) for a precipitation event with a return period of 10 years and a duration of one hour. The aim was to get an estimation of the potential contribution by green infrastructure to the capacity of stormwater treatment in the inner city of Stockholm. The result of the study was a potential capacity of 26 % of a precipitation event with a return period of 10 years and a duration of one hour. Future predictions of that same precipitation event in the year of 2100 resulted in a capacity of 21%. The thesis also presents the predicted consequences of climate change to the ecosystem service.

Till följd av klimatförändringar förväntas mer intensiva nederbördsmönster i framtiden. Dagvattenhantering är en essentiell del i urbana miljöer för att motverka översvämningar vid stora vattenflöden. Grön infrastruktur bidrar till dagvattenhanteringen genom dess ekosystemtjänst dagvatten- och flödesreglering. I uppsatsen undersöks ekosystemtjänstens kvantitativa potential att fånga upp vatten under ett 10-årsregn med varaktigheten en timme, med syftet att få en approximativ bild av grön infrastrukturs potentiella bidrag till dagvattenhanteringen i Stockholms innerstad. Studien är baserad på beräkningar i ArcGIS genom att försöka kvantifiera den gröna infrastrukturens bidragande parametrar till ekosystemtjänsten dagvatten- och flödesreglering. Resultatet av studien visade att dagens gröna infrastruktur har potential att ta hand om 26 % av ett 10-årsregn med varaktighet en timme, motsvarande siffra för nederbördsprojektioner för ett 10-årsregn år 2100 var 21 %. Uppsatsen redogör även för klimatförändringarnas påverkan på ekosystemtjänsten. / As a consequence of global warming, future precipitation patterns are predicted to be more intense. Thus, stormwater treatment plays an essential role in the urban environment to prevent flooding. Green infrastructure contributes to the treatment of stormwater through its ecosystem service “Stormwater treatment and flow regulation”. The objective of this study was to quantify the capacity of this ecosystem service by the use of Geographical Information Systems (GIS) for a precipitation event with a return period of 10 years and a duration of one hour. The aim was to get an estimation of the potential contribution by green infrastructure to the capacity of stormwater treatment in the inner city of Stockholm. The result of the study was a potential capacity of 26 % of a precipitation event with a return period of 10 years and a duration of one hour. Future predictions of that same precipitation event in the year of 2100 resulted in a capacity of 21%. The thesis also presents the predicted consequences of climate change to the ecosystem service.

Stormwater runoff from urban areas is a major source of pollution to surface water bodies. The discharge of nutrients such as nitrogen and phosphorus is particularly damaging as it results in harmful algal blooms which can limit the beneficial use of a water body. Stormwater best management practices (BMPs) have been developed over the years to help address this issue. While BMPs have been investigated for years, their use has been somewhat limited due to the fact that much of the data collected is for specific applications, in specific regions, and it is unknown how these systems will perform in other regions and for other applications. Additionally, the research was spread across the literature and performance data was not easily accessible or organized in a convenient way. Recently, local governments and the USEPA have begun to collect this data in BMP manuals to help designers implement this technology. That being said, many times a single BMP is insufficient to meet water quality and flood control needs in urban areas. A treatment train approach is required in these regions. In this dissertation, the development of methodologies to evaluate the performance of two BMPs, namely green roofs and pervious pavements is presented. Additionally, based on an extensive review of the literature, a model was developed to assist in the evaluation of site stormwater plans using a treatment train approach for the removal of nutrients due to the use of BMPs. This model is called the Best Management Practices Treatment for Removal on an Annual basis Involving Nutrients in Stormwater (BMPTRAINS) model. The first part of this research examined a previously developed method for designing green roofs for hydrologic efficiency. The model had not been tested for different designs and assumed that evapotranspiration was readily available for all regions. This work tested this methodology against different designs, both lab scale and full scale. Additionally, the use of the Blaney-Criddle equation was examined as a simple way to determine the ET for regions where data was not readily available. It was shown that the methods developed for determination of green roof efficiency had good agreement with collected data. Additionally, the use of the Blaney-Criddle equation for estimation of ET had good agreement with collected and measured data. The next part of this research examined a method to design pervious pavements. The water storage potential is essential to the successful design of these BMPs. This work examined the total and effective porosities under clean, sediment clogged, and rejuvenated conditions. Additionally, a new type of porosity was defined called operating porosity. This new porosity was defined as the average of the clean effective porosity and the sediment clogged effective porosity. This porosity term was created due to the fact that these systems exist in the exposed environment and subject to sediment loading due to site erosion, vehicle tracking, and spills. Due to this, using the clean effective porosity for design purposes would result in system failure for design type storm events towards the end of its service life. While rejuvenation techniques were found to be somewhat effective, it was also observed that often sediment would travel deep into the pavement system past the effective reach of vacuum sweeping. This was highly dependent on the pore structure of the pavement surface layer. Based on this examination, suggested values for operating porosity were presented which could be used to calculate the storage potential of these systems and subsequent curve number for design purposes. The final part of this work was the development of a site evaluation model using treatment train techniques. The BMPTRAINS model relied on an extensive literature review to gather data on performance of 15 different BMPs, including the two examined as part of this work. This model has 29 different land uses programmed into it and a user defined option, allowing for wide applicability. Additionally, this model allows a watershed to be split into up to four different catchments, each able to have their own distinct pre- and post-development conditions. Based on the pre- and post-development conditions specified by the user, event mean concentrations (EMCs) are assigned. These EMCs can also be overridden by the user. Each catchment can also contain up to three BMPs in series. If BMPs are to be in parallel, they must be in a separate catchment. The catchments can be configured in up to 15 different configurations, including series, parallel, and mixed. Again, this allows for wide applicability of site designs. The evaluation of cost is also available in this model, either in terms of capital cost or net present worth. The model allows for up to 25 different scenarios to be run comparing cost, presenting results in overall capital cost, overall net present worth, or cost per kg of nitrogen and phosphorus. The wide array of BMPs provided and the flexibility provided to the user makes this model a powerful tool for designers and regulators to help protect surface waters.

Silt fence is one of the most widely used perimeter control devices and is considered an industry standard for use in the control of sediment transport from construction sites. Numerous research studies have been conducted on the use of silt fence as a perimeter control, including a number of studies involving controlled laboratory flume tests and outdoor tests performed in the field on construction sites with actual monitored storm events. In field tests, due to the random and uncontrollable nature of real storm events and field conditions, studies have shown difficulty in evaluating silt fence performance. These field studies have shown the need for performance testing of silt fence in a more controlled environment, which can also simulate the actual use and performance in the field. This research, which is a continuation of ongoing research on silt fence fabrics at UCF Stormwater and Management Academy, was conducted in order to evaluate silt fence performance under simulated field conditions. Presented in this thesis are evaluation of two silt fence fabrics, a woven (ASR 1400) fabric and nonwoven (BSRF) fabric. Both fabrics were installed separately on a tilted test bed filled with a silty-sand soil and subjected to simulated rainfall. Previous field studies on the performance of silt fence fabrics have evaluated the turbidity and sediment removal efficiencies only after the rain event, with the assumption that the efficiency values represent the true overall performance of silt fence. The results of this study revealed that the turbidity and suspended sediment performance efficiencies of silt fence were significantly affected by the time of sampling. The performance efficiencies during rainfall remained less than 55 percent, however, after the rainfall event ended, the performance efficiencies increased over time, reaching performance efficiency upwards of 90 percent. The increase in efficiency after rainfall was due to the constant or decreasing ponding depth behind the silt fence, increased filtration due to fabric clogging, and sedimentation of suspended particles. The nonwoven fabric was found to achieve higher removal efficiencies and flow-through rates both during and after the rain event when compared with the woven fabric. However, over the entire test duration (during and after rainfall combined), the projected overall efficiencies of both fabrics were similar. The projected overall average turbidity performance efficiencies of the woven and nonwoven silt fence fabrics was 80 and 78 percent, respectively. Both fabric types also achieved comparable overall average suspended sediment concentration efficiencies of 79 percent. This result leads to the conclusion that silt fence performance in the field is dependent on three main processes: filtration efficiency occurring during the rain event, filtration and sedimentation efficiency occurring after the rainfall event, and flow-through rate of the silt fence fabrics. Decreases in the flow-through rate lead to increases in the overall efficiency. This thesis quantifies the different mechanisms by which these processes contribute to the overall efficiency of the silt fence system and shows how these processes are affected by different conditions such as the degree of embankment slope and rainfall intensity.

To maintain the quality of receiving water bodies, it is desirable to remove total phosphorus (TP) in stormwater runoff. Many media filtration technologies have been developed to achieve TP and soluble reactive phosphorus (SRP) removal. Efficient media adsorption is essential to insure control of stormwater phosphorus inputs to the receiving water body. This project develops and analyzes a functionalized Biosorption Media (BAM) to remove phosphorus species from stormwater runoff. One goal of this project is to find the BAM values for coefficients such as maximum adsorption capacity (QM: 4.35E-05) for the media through SRP isotherm equilibrium experiments using the Langmuir and Freundlich models. In addition, an upflow column experiment was also performed to study BAM nutrient removal from stormwater runoff. Finally, the information from the isotherm and the column experiments are used to estimate the life expectancy or quantity required of the media, and to define the effectiveness of BAM in phosphorus removal. The result of this study shows that BAM is a feasible stormwater treatment that can remove 60% SRP and > 40% TP at temperature between 21-23°C. The media is adequately modeled by both the Langmuir and the Freundlich models over the concentration range of interest in stormwater.

A change in surface condition of a watershed, which is usually caused by development, can have measured effects on the naturally occurring hydrologic cycle and nitrogen cycle. This could result in environmental problems, such as reduced springflow and eutrophication. In an effort to address these issues, a combination of best management practices (BMPs) can be adhered to. The practice of using excess stormwater as a source for irrigation is proposed as a BMP for the minimization of impacts by development to the hydrologic and nitrogen cycles. To study the proposed BMP, a field experiment was installed in an outdoor location on the UCF main campus in Orlando, Florida. The experiment consists of three soil chambers, (2x2x4 ft, L:W:H), filled with compacted soil and covered with St. Augustine grass to simulate a suburban lawn. The grass was irrigated up to twice a week with detained stormwater with a nitrate nitrogen concentration of up to 2 mg/L. A mass balance and a total nitrogen balance were performed to determine evapotranspiration (ET) and impacts on groundwater nitrogen content. It was determined that the groundwater characteristics are largely dependent on the characteristics of the soil. The input nitrogen (precipitation and irrigation) was mostly in the form of nitrate and the output nitrogen (groundwater) was mostly in the form of ammonia. A total nitrogen mass balance indicated the mass output of nitrogen was significantly larger than mass input of nitrogen, which was due to ammonia leaching from the soil. Only small concentrations of nitrate were detected in the groundwater, resulting in an estimated nitrate removal (conversion to ammonia) of 97 percent at a depth of four feet when the input nitrate concentration was 2 mg/L. The average ET of the three chambers was compared to the estimated ET from the modified Blaney-Criddle equation on a monthly basis and a yearly basis. The modified Blaney-Criddle equation was proven to be accurate for estimating the actual ET for this application: irrigated St. Augustine grass in the Central Florida climate. In conclusion, using the available literature and the data collected from the field experiment, it was shown through an example design problem that the proposed BMP of using excess stormwater as a source for irrigation can help achieve a pre- versus postdevelopment volume balance and can help control post-development nitrate emissions.

Throughout Central Florida surface water and ground water are decreasing in quantity and quality in part because of excess Nitrate and Phosphorus nutrients. Stormwater runoff serves as a medium for transport of Nitrate and Phosphorus to surface water and ground water. The goal of this experiment is assess the Nitrate and Phosphorus removal in stormwater using select media. The results of a literature search, batch test experimentation and column test experimentation are used to determine an optimal media blend that may be implemented in detention ponds to reduce Nitrate and Phosphorus. The extensive literature search revealed 32 different media that may be used to remove Nitrate and Phosphorus. Each potential media was qualitatively and quantitatively evaluated based on 5 criteria: 1) relevance, 2) permeability, 3) cost, 4) availability in Florida, and 5) additional environmental benefit. The top 7 performing media: Florida peat, sandy loam, woodchips, crushed oyster shell; crushed limestone, tire crumb and sawdust were selected for batch test experimentation. The aerobic conditions in batch test experimentation prohibited the growth of denitrifying bacteria, therefore media mixes were selected for column test experimentation based on Ammonia and Orthophosphate concentrations. Batch test experimentation showed the most effective media to be 50% sand, 30% tire crumb, 20% sawdust by weight (media mix 1) and 50% sand, 25% sawdust, 15% tire crumb, 10% limestone by weight (media mix 2). Media mix 1, media mix 2 and a control are tested in column test experimentation, where the control is site soil from Hunters Trace development in Ocala, Florida. Column test experimentation models a dry detention pond where water passes through a 48 inch unsaturated zone then a 48 inch saturated zone. To test Nitrate and Orthophosphate removal potential, pond water augmented with Nitrate (0.38, 1.26, 2.5 mg/L NO3-N) and Orthophosphate (0.125, 0.361, 0.785 mg/L PO4-P) was pumped into the columns. Media mix 1 and media mix 2 outperformed the control in both Nitrate and Orthophosphate removal. Media mix 1 and media mix 2 had Nitrate removal efficiencies ranging from 60% to 99% and the control had Nitrate removal efficiencies ranging from 38%-80%. Media mix 1 and media mix 2 averaged Orthophosphate removal efficiencies ranging from approximately 42% to 67%. For every run in every influent Orthophosphate concentration the saturated control added Orthophosphate to the water. The Nitrate and Orthophosphate removal performances for media mix 1 and media mix 2 could not be directly compared because of different influent saturated nutrient concentrations.

There are many possible ways to mitigate stormwater pollution, but this study focused on the DrainPacTM catchment basin insert and the feasibility of integrating N-halamine biocidal brominated beads into the filter system. This study was divided into three sections. The first section involved testing a DrainPacTM filter for treatable flow rates, head loss, and removal of solids, oil, and bacteria. The DrainPacTM filter is designed to be installed in a stormwater catch basin. The filter is composed of a 12 x 41 inch metal frame with textile filter media attached to it in a basket shape. The upper portion of one panel of the filter basket is made from a plastic mesh to allow overflow if the filter is overloaded. The second section of this study involved testing N-halamine brominated biocidal beads in laboratory-scale columns, and the third section involved integrating the beads into the DrainPacTM filter and testing it full scale. For the DrainPacTM filter tests, the unit was installed into a custom-built test flume which was designed to mimic the conditions that would be encountered in a real stormwater application. The flume was supplied with a gravity-fed stream of water from a retention pond located on the Cal Poly, San Luis Obispo campus. The initial tests were conducted to determine the amount of head loss produced by the filter. First, the clean filter was subjected to flow rates between 20 and 200 GPM. The filter showed very minimal head loss (0.5 to 9.1 cm for 20 to 200 GPM) when not loaded with solids. Next, the filter was subjected to 200 GPM flow with a solids concentration of between 80 and 100 mg/L until it failed (overflowed). This occurred after 625 g of solids had been added to the filter. After the filter had been loaded with solids to the point of overflow at 200 GPM, it was tested to determine what flow rate could be filtered with the solids present. The fully loaded filter was able to pass a flow rate of up to 80 GPM before overflowing. The DrainPacTM filter removed solids at a range of efficiencies from 83 to 91% at flow rates between 20 and 200 GPM. The higher removal efficiencies were achieved at the lower flow rates. The filter removed oil at efficiencies ranging between 40 and 80%. The oil removal efficiency did not appear to depend on the flow rate. The DrainPacTM filter did not remove bacteria under the test conditions. Following the DrainPacTM experiments, 0.3 mm and 0.8 mm diameter N-halamine brominated biocidal beads were tested in the lab using a laboratory glass column. At flow rates between 0.28 and 1.4 mL/sec, a 1 cm bed height of the 0.3 mm beads was found to produce head losses between 19 and 51.7 cm. The 0.8 mm beads produced head losses ranging from 11.9 to 47.7 cm when tested over the same range of flow rates. These flow rates represent nominal velocities between 0.36 and 1.8 cm/sec which would be expected in the DrainPacTM filter. The beads were then tested to determine how effectively they inactivate bacteria in a stream of water. Contact time after flowing through the column was found to be the key factor in how efficiently the beads worked. When the effluent samples were instantly quenched with sodium thiosulfate, the bacteria removal results matched those observed for the control (beads without bromine). When the samples were quenched directly after collection by adding the sodium thiosulfate to the sample as soon as the desired sample volume had been collected (95 to 285 seconds depending on flow rate), between 95 and over 99 percent of the bacteria were inactivated. After 10 minutes, all of the bacteria were inactivated. The final test involved integrating the N-halamine brominated beads into the DrainPacTM filter for a full scale test. Two sleeves containing 1400 grams of beads were laid into a DrainPacTM filter which was custom built to concentrate the flow through the beads. This system was tested using pond water with an average of 298 CFU/100 mL coliform bacteria at a flow rate of 36 GPM. The results of this test were very similar to the results of the lab scale testing. Contact time again proved to be necessary for bacteria inactivation. The filter with integrated N-halamine beads removed between 72 and 100% of bacteria with contact time between 30 seconds and 10 minutes.

Heavy precipitation events are expected to increase in intensity and frequency, due to global warming. Sewer systems might overload during heavy rainfall, resulting in floods which potentially affect all municipalities in Sweden. Traditionally, stormwater is seen as pipe-related problem, but a transition towards Sustainable Drainage Systems (SuDS) has started. SuDS aim to reduce the quantity of the runoff from the site, slow down the runoff to allow (in)filtration, and provide treatment of the surface water before discharge. In Sweden, municipalities are responsible for the sewer system and realization and implementation of climate change adaptation measures, like SuDS. Tools and models support the highly complex selection, location, and design of SuDS, by systematically providing the most relevant information that represents the actual drainage system in the best way possible. Furthermore, models are used to predict the behaviour of SuDS, which may form Decision Support Systems (DSS). The highest interest in SuDS modelling and DSS lies in water quantity, however existing models are complex and lack flexibility, transferability, and stakeholder inclusion. The aim of this project is to provide a tool for the Municipality of Östersund that aids in the decision-making and design process for the implementation of SuDS, concerning their capacity to store stormwater. The ‘SuDS water storage capacity calculator’ can be used to test what (combinations of) SuDS are able to store the stormwater of a heavy rainfall event.The following SuDS components were included in the calculator: extensive green roofs, underground infiltration systems, infiltration basins, swales, porous pavements, detention basins, ponds, and wetlands. Secondly, the technical criteria forming the basis of the calculator were identified through a literature review. These criteria were used to calculate precipitation and the water storage capacity of each SuDS. The calculator was then built in Microsoft Powerpoint using Visual Basic for Applications (VBA). Two case studies were selected in Östersund and explored using the calculator. The water storage capacity of each SuDS component was calculated using scenarios in which 25%, 50%, 75%, and 100% of the total available area in each case study was used as input. Finally, four combinations of SuDS were tested concerning their water storage capacity. All calculated water storage capacity was compared to the amount of water falling on the case study areas during a heavy precipitation event that only occurs once every 100 years.The developed calculator can be used to calculate water storage capacity of SuDS and precipitation in a simple way. The tool contains user input and default values, which can still be changed. Furthermore, the calculator allows comparison between the amount of precipitation and water storage capacity. The results of the scenarios show that underground infiltration systems and detention basins have the highest potential to store stormwater, followed by infiltration basins, porous pavements, and ponds or wetlands. The calculator has limited design options, due to its simplification of reality. However, its limits are mostly applicable further in the designing process. The4calculator gives a rough estimate of the potential water storage capacity of a variety of SuDS components. The calculator is a useful tool before the design process has started, by providing an indication of the options that are worthwhile to consider in terms of water storage capacity. Furthermore, opportunities for optimization of the tool were recognized. The water storage capacity resulting from the different scenarios was compared to the precipitation falling on each case study area. Realistically, the amount of precipitation that exceeds the capacity of the sewer system might not fall directly where the SuDS are located. Finally, the calculator allows applications of a wider range of combinations of SuDS components. / <p>2022-06.16</p>

The studies in this dissertation address the issue of variability in runoff generation and pollutant concentration in urban areas, and specifically in the catchments of stormwater control measures. There is an imperfect correlation between runoff volumes and the capture area and land uses of urban catchments. Variable capture areas and uncertainty in urban runoff sources complicate stormwater control measure design and urban stream assessment. Four stormwater control measures in upstream suburban Philadelphia, ranging in capture area from 0.11 ha to 32 ha, were monitored, sampled, and modeled. Sampling was conducted in the watersheds of Wissahickon Creek, Tookany Creek, and Pennypack Creek. The approaches discussed below have the goal of better understanding runoff and the movement of associated contaminants into stormwater retention basins and streams. Rather than viewing runoff generation and contaminant transport as a static process, this work proposes that the amount of runoff contributed from different areas of a catchment changes during and between storm events, and that the origin and concentration of contaminants change as a result. Linking source areas to runoff volumes through natural and modeled tracers could improve predictions of water quality and quantity in stormwater control measures in urban streams. Nitrate (NO3–) isotope ratios were used as tracer of flow from different urban land uses. Time series samples of stormwater runoff entering two stormwater control measures (a constructed wetland and a small bioretention basin) were collected and analyzed to distinguish sources of NO3– by samples’ δ15N and δ18O ratios. A Bayesian mixing model was used to determine that NO3– sources were a mix of soil nitrogen (N) and atmospheric deposition across six storm events. Furthermore, atmospheric versus soil N sources varied throughout the storms. The large catchment of the constructed wetland had more NO3– source variability between samples compared to the small catchment of the bioretention basin. Thus, the NO3– isotopes suggest more distinct flow paths in the large catchment and more mixing of flow across land uses in the small catchment. Quantifying flow path variability from storm to storm and between different catchments can improve design and placement of urban stormwater control measures. A distributed hydrologic model, GSSHA, was used to simulate overland runoff from impervious and semi-pervious land covers in the catchment of a stormwater control measure. The positions of low vegetation and impervious land uses over the catchment were rearranged to create hypothetical catchments during four storm events. Fluctuating source proportions over time suggested that grab samples might not be adequate for capturing average overland runoff chemistry. It was also found that the portion of total runoff volume from impervious areas varied from 50 to 75% while the relative proportion of impervious cover remained constant at 54%. Land use percentages averaged over capture areas are frequently used to estimate runoff amounts and pollutant concentrations, but this model disrupts the assumption that urban hydrologic responses can be predicted from imperviousness alone. Overland runoff was measured and modeled before and after the installation of two stormwater control measures, a berm and a bioswale. Discharge in the stream was modeled for 9 storms ranging in size from 14 to 54 mm. We found that during 4 of the modeled storms there was no decrease in stream discharge and decreases in discharge were generally only observed for low intensity storms. Furthermore, only 5% of the stream catchment was captured by SCMs. Modeled tracers, used to track runoff contributions from areas upslope of the SCMs found that the size of upslope contributing areas did not predict the proportion of runoff generated in each area. Field data to support the models included water level loggers and samples of overland runoff collected in subsurface stormwater casing. After the SCMs were installed, less water was captured in downslope sampling bottles, but new flow paths developed. Furthermore, significant variation was observed in upslope concentrations of dissolved nutrients and total suspended solids, casting doubt on whether point samples of urban overland runoff geochemistry can be representative given variable runoff generation and heterogeneous land uses. This study points out the challenges in evaluating stormwater control measures and reveals that source areas’ contribution to stream flow varies independently of their size. Therefore, modeling before stormwater control measure installation is recommended to determine the factors that influence a capture area’s contribution to urban streamflow. / Geoscience