Quantifying the impact of urban runoff injection on groundwater Enhancement in a semi-arid environment using SWMM and MOFLOW Model

<p>In the urban area, surface runoff can be utilized effectively to improve groundwater table through rainwater harvesting. The main aims of this study were to:1) investigate the potential of the surface runoff to inject into Urmia aquifer and increase groundwater recharge of this aquifer using SWMM - MOFLOW Model, 2) to investigate the quality of the urban runoff for aquifer recharge, and 3) to investigate the feasibility and effeteness of the artificial recharge via injection wells in a semi-arid area. Urmia city with an area of 930 Km2 is located at the West of the Urmia Lake in the North-West of Iran. The study aquifer has a negative groundwater budget, while some of the sub basin in the study watershed is prone to flood in the falling season. In this study, based on the location of surcharged channels, the quantity of rechargeable surface runoff to inject into the aquifer was estimated via SWMM model. Calibrated MODFLOW model was applied to predict the potential effects of the injectable water runoff on the groundwater surface. Estimated runoff by SWMM model was used as the input of the MODFLOW model. The quantity of the heavy metals (Fe2+, Zn2+, Mn2+, Pb and Cu2+) TDS and pH were measured to control runoff quality. According to the results, 1.12 million cubic meters (MCM) per year of runoff can be injected to the aquifer via 9 designed injection wells. This amount is equivalent to the annual loss of the aquifer (about 20 centimeters per year) that can ensure the stability of the aquifer in the injection area.</p>

Analysis of the Inflow Characteristics of Separate Sewer Systems for Rainfall Using an XP-SWMM Model and the SSOAP Toolbox

Even after the sewer system rehabilitation project, sewer system-related problems caused by inflow still persist. However, analysis of the characteristics of the inflow has been limited to specific rainfall events and monitoring points. This study analyzed inflow characteristics according to rainfall events using an XP-SWMM model and the Sanitary Sewer Overflow Analysis and Planning (SSOAP) Toolbox. In this study, the XP-SWMM model was built for sewers and collecting pipes in urban areas where classification projects were completed. The R, T, and K parameters were calculated using the SSOAP tool based on the sewer volume data of the study area. The calculated parameters were inputted into the XP-SWMM model and used to analyze R, T, and K of unmeasured sampling intervals. The amount of rainfall-derived inflow and infiltration (RDII) increased according to the amount of rainfall, and the correlation coefficient between the amount of rainfall and the amount of RDII was 0.9352, indicating a high correlation. The results of this study can support efficient facility planning that reflects the rainfall characteristics of specific areas, including areas where actual survey of sewage data is not possible.

Analyses Of The Hydrologic Performance Of Bioretention Facilities

Due to urbanization, and replacing natural pervious lands by impermeable surfaces, the patterns of rainfall-runoff are altered and thus, negatively influence natural water systems regarding both water quantity and water quality. Bioretention as an efficient LID practice has received significant interest in the recent years. Bioretention practice due to its advantages can be considered as one of the most promising LID practices that maintains the fundamental hydrologic functions in a natural environment and can be integrated into neighborhood landscaping. The primary objective of the current study is analyzing the effects of inflow and outflow characteristics on right-of-way (roadside) bioretention facilities. Inlet and outlet flow hydrographs under several design storm conditions were examined. After the formulation of a SWMM model (node and link plus LID), numerical experiments including sensitive analysis will be designed to simulate and investigate the runoff control performance of a right-of-way bioretention facility. The effective length of the bioretention was found by FLOW3D software (finite element). The performance of the bioretention cell with the effective lengths (12 &16m) reinvestigated and results compared to original bioretention cell

Analyses Of The Hydrologic Performance Of Bioretention Facilities

Due to urbanization, and replacing natural pervious lands by impermeable surfaces, the patterns of rainfall-runoff are altered and thus, negatively influence natural water systems regarding both water quantity and water quality. Bioretention as an efficient LID practice has received significant interest in the recent years. Bioretention practice due to its advantages can be considered as one of the most promising LID practices that maintains the fundamental hydrologic functions in a natural environment and can be integrated into neighborhood landscaping. The primary objective of the current study is analyzing the effects of inflow and outflow characteristics on right-of-way (roadside) bioretention facilities. Inlet and outlet flow hydrographs under several design storm conditions were examined. After the formulation of a SWMM model (node and link plus LID), numerical experiments including sensitive analysis will be designed to simulate and investigate the runoff control performance of a right-of-way bioretention facility. The effective length of the bioretention was found by FLOW3D software (finite element). The performance of the bioretention cell with the effective lengths (12 &16m) reinvestigated and results compared to original bioretention cell

CALIBRATION AND VALIDATION OF SWMM MODEL IN A SUB CATCHMENT IN ELDORET TOWN, KENYA

Flooding in Eldoret town has been occurring during heavy downpours resulting in loss of property, live and interruption of transportation systems. This study aimed at determining the catchment characteristics in Eldoret town for the calibration and validation of SWMM5 model. This model was developed by US Environmental Protection Agency. The model has been evolving from Version 1 in 1971 to Version 5 of 2005 called SWMM5. It can simulate runoff quantity in any given catchment. Rainfall was measured using rain gauge while discharge was measured using current meter. Digital Elevation Model of the study area was also obtained. The results showed that the catchment drained an area of approximately 696.5 hectares with a total of 23 sub catchments. The average slope was found to be 2.57% and the mean average imperviousness was 25.72%. The drain base flow was found to be 0.002 m3/s. However, during prolonged rainfall, the discharge increased up to 32.4 m3/s. The maximum rainfall observed during the study period was 32.4 mm which resulted in the maximum average discharge of 0.131m3/s and resulted in overflow in the drain. Calibrated model had N-Imperv of 0.45, Dstore-Imperv of 2.5 and Dstore-Perv of 8. ISE values of 1.9 and 1.4 were observed for calibration and validation, respectively. NSE values of 0.97 and 0.99 were observed for calibration and validation, respectively. This meant that model excellently simulated rainfall-discharge relationship in the study area and can be used for final design by the Eldoret town engineers. Future study is required to calibrate the model based on more measurements of rainfall and their discharges in the catchment.

Optimization of Low Impact Development Based on SWMM and Genetic Algorithm: Case Study in Tianjin, China

&lt;p&gt;Low impact development (LID) is an important measure to control the total amount of rainwater runoff from the source and solve the problem of non-point source pollution. However, there are many kinds of LID facilities, and the selection and layout of these facilities are restricted by the local physical and geographical conditions, hydrogeological characteristics, water resources, rainfall patterns and other factors. Therefore, the selection of LID facilities and the determination of optimization scheme are the main challenges for the construction of LID rainwater system. In this study, SWMM model and genetic algorithm (GA) are used to optimize the layout of LID. The multiple objectives include runoff reduction, occupied area and lifecycle cost. The results show that the combined LID facility scheme has obvious control effect on runoff reduction in the 10-year rainfall process.&lt;/p&gt;

Hydraulic modeling of combined sewers overflow integrating the results of the SWMM and CFX models.

This study proposes a methodology for the calibration of combined sewer overflow (CSO), incorporating the results of the three-dimensional ANSYS CFX model in the SWMM one-dimensional model. The procedure consists of constructing calibration curves in ANSYS CFX that relate the input flow to the CSO with the overflow, to then incorporate them into the SWMM model. The results obtained show that the behavior of the flow over the crest of the overflow weir varies in space and time. Therefore, the flow of entry to the CSO and the flow of excesses maintain a non-linear relationship, contrary to the results obtained in the one-dimensional model. However, the uncertainty associated with the idealization of flow methodologies in one dimension is reduced under the SWMM model with kinematic wave conditions and simulating CSO from curves obtained in ANSYS CFX. The result obtained facilitates the calibration of combined sewer networks for permanent or non-permanent flow conditions, by means of the construction of curves in a three-dimensional model, especially when the information collected in situ is limited.