Support Vector Regression Models of Stormwater Quality for a Mixed Urban Land Use

The present study is an attempt to model the stormwater quality of a stream located in Pune, India. The city is split up into twenty-three basins (named A to W) by the Pune Municipal Corporation. The selected stream lies in the haphazardly expanded peri-urban G basin. The G basin has constructed sto...

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Main Authors: Mugdha P. Kshirsagar, Kanchan C. Khare
Format: Article
Language:English
Published: MDPI AG 2023-03-01
Series:Hydrology
Subjects:
Online Access:https://www.mdpi.com/2306-5338/10/3/66
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author Mugdha P. Kshirsagar
Kanchan C. Khare
author_facet Mugdha P. Kshirsagar
Kanchan C. Khare
author_sort Mugdha P. Kshirsagar
collection DOAJ
description The present study is an attempt to model the stormwater quality of a stream located in Pune, India. The city is split up into twenty-three basins (named A to W) by the Pune Municipal Corporation. The selected stream lies in the haphazardly expanded peri-urban G basin. The G basin has constructed stormwater drains which open up in this selected open stream. The runoff over the regions picks up the non-point source pollutants which are also added to the selected stream. The study becomes more complex as the stream is misused to dump trash materials, garbage and roadside litter, which adds to the stormwater pollution. Experimental investigations include eleven distinct locations on a naturally occurring stream in the G basin. Stormwater samples were collected for twenty-two storm events, for the monsoon season over four years from 2018–2021, during and after rainfall. The physicochemical characteristics were analyzed for twelve water quality parameters, including pH, Conductivity, Turbidity, Total solids (TS), Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Bio-chemical Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), Dissolved Oxygen (DO), Phosphate, Ammonia and Nitrate. The Water Quality Index (WQI) ranged from 46.9 to 153.9 and from 41.20 to 87.70 for samples collected during and immediately after the rainfall, respectively. Principal Component Analysis was used to extract the most significant stormwater quality parameters. To understand the non-linear complex relationship of rainfall characteristics with significant stormwater pollutant parameters, a Support Vector Regression (SVR) model with Radial Basis Kernel Function (RBF) was developed. The Support Vector Machine is a powerful supervised algorithm that works best on smaller datasets but on complex ones with the help of kernel tricks. The accuracy of the model was evaluated based on normalized root-mean-square error (NRMSE), coefficient of determination (R<sup>2</sup>) and the ratio of performance to the interquartile range (RPIQ). The SVR model depicted the best performance for parameter TS with NRMSE (0.17), R<sup>2</sup> (0.82) and RPIQ (2.91). The unit increase or decrease in the coefficients of rainfall characteristics displays the weighted deviation in the values of pollutant parameters. Non-linear Support Vector Regression models confirmed that both antecedent dry days and rainfall are correlated with significant stormwater quality parameters. The conclusions drawn can provide effective information to decision-makers to employ an appropriate treatment train approach of varied source control measures (SCM) to be proposed to treat and mitigate runoff in an open stream. This holistic approach serves the stakeholder’s objectives to manage stormwater efficiently. The research can be further extended by selecting a multi-criteria decision-making tool to adopt the best SCM and its multiple potential combinations.
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spelling doaj.art-8a9e27706d064a048049253a2021f22d2023-11-17T11:25:59ZengMDPI AGHydrology2306-53382023-03-011036610.3390/hydrology10030066Support Vector Regression Models of Stormwater Quality for a Mixed Urban Land UseMugdha P. Kshirsagar0Kanchan C. Khare1Department of Civil Engineering, Symbiosis Institute of Technology, Symbiosis International Deemed University, Pune 412115, Maharashtra, IndiaDepartment of Civil Engineering, Symbiosis Institute of Technology, Symbiosis International Deemed University, Pune 412115, Maharashtra, IndiaThe present study is an attempt to model the stormwater quality of a stream located in Pune, India. The city is split up into twenty-three basins (named A to W) by the Pune Municipal Corporation. The selected stream lies in the haphazardly expanded peri-urban G basin. The G basin has constructed stormwater drains which open up in this selected open stream. The runoff over the regions picks up the non-point source pollutants which are also added to the selected stream. The study becomes more complex as the stream is misused to dump trash materials, garbage and roadside litter, which adds to the stormwater pollution. Experimental investigations include eleven distinct locations on a naturally occurring stream in the G basin. Stormwater samples were collected for twenty-two storm events, for the monsoon season over four years from 2018–2021, during and after rainfall. The physicochemical characteristics were analyzed for twelve water quality parameters, including pH, Conductivity, Turbidity, Total solids (TS), Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Bio-chemical Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), Dissolved Oxygen (DO), Phosphate, Ammonia and Nitrate. The Water Quality Index (WQI) ranged from 46.9 to 153.9 and from 41.20 to 87.70 for samples collected during and immediately after the rainfall, respectively. Principal Component Analysis was used to extract the most significant stormwater quality parameters. To understand the non-linear complex relationship of rainfall characteristics with significant stormwater pollutant parameters, a Support Vector Regression (SVR) model with Radial Basis Kernel Function (RBF) was developed. The Support Vector Machine is a powerful supervised algorithm that works best on smaller datasets but on complex ones with the help of kernel tricks. The accuracy of the model was evaluated based on normalized root-mean-square error (NRMSE), coefficient of determination (R<sup>2</sup>) and the ratio of performance to the interquartile range (RPIQ). The SVR model depicted the best performance for parameter TS with NRMSE (0.17), R<sup>2</sup> (0.82) and RPIQ (2.91). The unit increase or decrease in the coefficients of rainfall characteristics displays the weighted deviation in the values of pollutant parameters. Non-linear Support Vector Regression models confirmed that both antecedent dry days and rainfall are correlated with significant stormwater quality parameters. The conclusions drawn can provide effective information to decision-makers to employ an appropriate treatment train approach of varied source control measures (SCM) to be proposed to treat and mitigate runoff in an open stream. This holistic approach serves the stakeholder’s objectives to manage stormwater efficiently. The research can be further extended by selecting a multi-criteria decision-making tool to adopt the best SCM and its multiple potential combinations.https://www.mdpi.com/2306-5338/10/3/66support vectorregression modelsurban stormwater qualitymixed land usenonpoint pollutantswater quality index
spellingShingle Mugdha P. Kshirsagar
Kanchan C. Khare
Support Vector Regression Models of Stormwater Quality for a Mixed Urban Land Use
Hydrology
support vector
regression models
urban stormwater quality
mixed land use
nonpoint pollutants
water quality index
title Support Vector Regression Models of Stormwater Quality for a Mixed Urban Land Use
title_full Support Vector Regression Models of Stormwater Quality for a Mixed Urban Land Use
title_fullStr Support Vector Regression Models of Stormwater Quality for a Mixed Urban Land Use
title_full_unstemmed Support Vector Regression Models of Stormwater Quality for a Mixed Urban Land Use
title_short Support Vector Regression Models of Stormwater Quality for a Mixed Urban Land Use
title_sort support vector regression models of stormwater quality for a mixed urban land use
topic support vector
regression models
urban stormwater quality
mixed land use
nonpoint pollutants
water quality index
url https://www.mdpi.com/2306-5338/10/3/66
work_keys_str_mv AT mugdhapkshirsagar supportvectorregressionmodelsofstormwaterqualityforamixedurbanlanduse
AT kanchanckhare supportvectorregressionmodelsofstormwaterqualityforamixedurbanlanduse