Modeling Pollutant Buildup and Washoff Parameters for SWMM Based on Land Use in a Semiarid Urban Watershed

Flow duration curve (FDC) is widely used in hydrology to assess streamflow in a river basin. In this study, a simple FDC model is developed for monthly streamflow data. The model consists of several steps including the nondimensionalization and then normalization in case the monthly streamflow data do not fit the normal probability distribution function. The normalized quantiles are calculated after which a back transformation is applied to the normalized quantiles to return back to the original dimensional streamflow data. In order to calculate annual streamflow of the river basin, an empirical regression equation is proposed using the drainage area and the annual total precipitation only as the input. As the final step of the model, dimensional quantiles of FDC are calculated. Ceyhan River basin in southern Turkey is chosen for the case study. Forty-two streamflow gauging stations are considered; two thirds of the gauging stations are used for the model calibration, and one third for validation. The modeled FDCs are compared to the observation and assessed with a number of performance metrics. They are found similar to the observed ones with a relatively good performance; they are good in the mid and high flow parts particularly while the low flow part of FDCs might require further detailed analysis.The FDC of the hydrological basin is obtained from the observed streamflow data. However, hydrological basins are not always properly gauged [23]. Therefore, regional FDCs are developed to transfer information from gauged sites to ungauged sites through the use of morphological characteristics of the hydrological basin [24], the combination of basin characteristics with probability distribution functions [25] or the development of regression or polynomial equations based on the drainage area [26,27]. The landscape and climate characteristics are also used for regional FDCs of ungauged basins [28,29]. A particular example for the dimensionless regional FDC in watersheds with no or limited data was given by Ganora et al. [30]. The comparative study of Swain and Patra [31] on the regional FDCs in ungauged basins should finally be mentioned from the literature.Although a great experience is available in the literature on FDCs, research is still needed for ungauged basins particularly in developing countries where water resources development projects are in progress, and most of the hydrological basins are either ungauged, improperly gauged or poorly gauged. The transfer of FDC models developed for a gauged hydrological basin is not transferable to any another basin unless the basins are similar not only in terms of their hydrometeorological character but also in terms of their geomorphology [32]. With higher needs to water, smaller size river basins or subbasins within river basins, which are likely ungauged or poorly gauged, have gained importance for water resources development programs of countries under development. Therefore, studies on FDC models still emerge for ungauged river basins.This study aims at contributi...

Section: Applicationmentioning

confidence: 99%

Monthly Flow Duration Curve Model for Ungauged River Basins

Burgan

Aksoy

2020

“…Because the observed TSS concentration was unavailable, the calibration process for TSS concentration was impossible. The parameters set for the simulation of TSS load were the same as in the study of Tu and Smith [27]. The calibrated SWMM was used to generate flow and TSS loads under a 2-year, 3-h storm of 9.0 cm to utilize as the baseline, from which the effectiveness of any LID planning Water 2020, 12, 533 5 of 15 scenario was estimated.…”

Section: Baseline Condition Setupmentioning

confidence: 99%

Optimal Planning of Low-Impact Development for TSS Control in the Upper Area of the Cau Bay River Basin, Vietnam

Dang

2020

Recently, an increase in impervious area induced by the process of urbanization has significantly affected the quantity and quality of urban surface runoff. Among the pollutants of the storm flow, total suspended solids (TSS) are an extremely important cause of water quality deterioration. This paper aims to use the integrated nondominated sorting genetic algorithm (NSGA II)–Storm Water Management Model (SWMM) method to find optimal Low-Impact Development (LID) plans which ensure maximum TSS load reduction and minimum total relative cost. Green roofs, permeable pavements, and tree boxes with fixed parameters and unit costs were considered for seeking optimal planning alternatives in the Cau Bay river basin. The optimization process yielded a cost–effectiveness curve, which relates cost of LID implementation with its corresponding TSS reduction efficiencies. The advantage of the optimization approach was clarified when, with a defined cost of LID implementation, there was a significant difference in TSS reduction efficiencies between the optimal and non-optimal alternatives. The increase in return periods of rainfall patterns not only resulted in a reduction in the TSS removal efficiencies of LID practices at the outfall of the study area, but also spatially changed in terms of the TSS removal efficiencies of the sub-catchments. The return period of the rainfall patterns utilized for LID design should not exceed 2 years. The simulation–multi-optimization approach facilitates integration of LID practice plans into the urban infrastructure master plans in Vietnam.

“…The use of green infrastructure (GI) to control non-point pollution associated with stormwater has been written into law by municipalities around the world [1][2][3]. Such laws protect surface water bodies in and adjacent to urban areas from contaminants transported by stormwater as well as those released during combined sewer overflow events [4]. By reducing the volume of stormwater entering combined sewer systems, GI lowers pollutant loading, runoff velocity, and peak flow rates [5].…”

Section: Introductionmentioning

confidence: 99%

When Green Infrastructure Turns Grey: Plant Water Stress as a Consequence of Overdesign in a Tree Trench System

Caplan

Eisenman

et al. 2020

Self Cite

Green infrastructure (GI) systems are often overdesigned. This may be a byproduct of static sizing (e.g., accounting for a design storm’s runoff volume but not exfiltration rates) or may be deliberate (e.g., buffering against performance loss through time). In tree trenches and other GI systems that require stormwater to accumulate in an infiltration bed before it contacts the planting medium, overdesign could reduce plant water availability significantly. This study investigated the hydrological dynamics and water relations of an overdesigned tree trench system and identified factors contributing to, compounding, and mitigating the risk of plant stress. Water in the infiltration bed reached soil pits only once in three years, with that event occurring during a hydrant release. Moreover, minimal water was retained in soil pits during the event due to the hydraulic properties of the soil media. Through a growing season, one of the two tree types frequently experienced water stress, while the other did so only rarely. These contrasting responses can likely be attributed to roots being largely confined to the soil pits vs. reaching a deeper water source, respectively. Results of this study demonstrate that, in systems where soil pits are embedded in infiltration beds, overdesign can raise the storm size required for water to reach the soil media, reducing plant water availability between storms, and ultimately inducing physiological stress.