Application of fuzzy logic in river water quality modelling for analysis of industrialization and climate change impact on Sabarmati river

Rivers are critical to human life because they are strategically significant in the world, providing primary water supplies for various purposes. Rivers are the prime importance of any country as most of the cities are settled near the river. Due to developmental activities and increase in population, it will results into huge waste generation. Surface water quality is affected because of increasing urbanization and industrialization. The aim of this research is to examine the effect of climate change and industrialization on the water quality of the Sabarmati river using a mathematical model. For this study four important town along the lower Sabarmati River have been considered and water quality data was considered from 2005 to 2015. In this study different water quality parameters were considered to derive water quality model. Results shows the water quality in downstream after Ahmedabad city is worst compare to the other location where the Maximum WQI is 0.71 at Rasikapur and average WQI is 0.50 for the same location for last 15 year. It has been observed that effect of monsoon and also by comparing time scale water quality model role of regulations for industrialization also plays important role in quality of Sabarmati river.

Greenhouse gas dynamics in an anthropogenically modified tropical river continuum

<p>Recent decades have witnessed large scale modifications in the natural flow regime of river systems. What follows are shifts in various instream processes that ultimately govern the air-water fluxes of major greenhouse gases (GHGs) like CH<sub>4</sub>, CO<sub>2</sub>, and N<sub>2</sub>O. However, due to paucity of data, the process dynamics and controls on fluxes of GHGs in tropical rivers are understudied, contributing to uncertainty in their global budget. In this study, an attempt was made to estimate the fluxes of GHGs and thereby decipher the controls on evasive processes in an anthropogenically affected Sabarmati River (catchment ~ 27,674 km<sup>2</sup> and channel length ~371 km) located in semi-arid western India. After originating from a relatively pristine region, Sabarmati passes through a major twin city (Ahmedabad-Gandhinagar), where construction of a riverfront resulted in increased residence time of water within the city limits.</p><p>To compare and understand changes in in-stream biogeochemical processes as a result of human interventions, sampling was carried out at 50 sites along the Sabarmati river continuum and a parallel running, but not so anthropogenically modified, Mahi River along with their tributaries. Results indicated relatively lower fluxes of GHGs in pristine upstream of Sabarmati and Mahi River continuum with CH<sub>4</sub>, CO<sub>2</sub> and N<sub>2</sub>O fluxes at 0.99 ± 0.35 mg C m<sup>-2 </sup>d<sup>-1</sup>, 4250.99 ± 477.74 mg C m<sup>-2 </sup>d<sup>-1 </sup>and 0.055 ± 0.026 mg N m<sup>-2 </sup>d<sup>-1</sup> respectively. The effect of higher residence time of water could be seen in the riverfront with increased CH<sub>4 </sub>and N<sub>2</sub>O fluxes at 3.27 ± 1.02 mg C m<sup>-2 </sup>d<sup>-1 </sup>and 0.129 ± 0.024 mg N m<sup>-2 </sup>d<sup>-1</sup>, respectively. However, the CO<sub>2</sub> flux did not show much increase. The fluxes increased significantly post city limits until its mouth in the Arabian Sea with extremely large flux for methane (CH<sub>4</sub>: 102.84 ± 41.32 mg C m<sup>-2 </sup>d<sup>-1</sup>, CO<sub>2</sub>: 9563.58 ± 1252.43 mg C m<sup>-2 </sup>d<sup>-1</sup>, and N<sub>2</sub>O: 0.16 ± 0.11 mg N m<sup>-2 </sup>d<sup>-1</sup>, respectively). Overall, it appeared that even within the anthropogenically stressed river, the nature of flow regime, exerts significant control on cycling of elements leading to differential fluxes. Also, the level of coupling between nitrogen and carbon appeared to change within the course of the river.</p>

Integrating 1D-2D Hydrodynamic Model For Sabarmati Upper River Basin With Special Reference to Ahmedabad City Area

<p>In recent study, Gujarat has become one of the India’s most urbanized state, causing severe flash flooding. The Sabarmati river is one of the major west-flowing rivers in India and biggest river of north Gujarat.Urbanization should meet the population’s need by enlargement of paved areas, which has unusually changed the catchment’s hydrological and hydraulic characteristic. Therefor, the frequency of flash flooding in Sabarmati river has been increased. The Sabarmati river basin experienced eight times devastating flooding coendition between 1972 to 2020.Among which July 2017 flooding event breakdown a 112 years old record of 1905. The Dharoi dam and Wasna barrage on Sabarmati river and surrounding district Kheda, Mehsana, Gandhinagar, Ahmedabad received a huge rainfall caused anomalous inflow to tributary which forced the dam authorities to release huge discharge in short duration which leads to flooding. The Sabarmati riverfront of Ahmedabad had been going under water for five days due incessant rainfall in the city that leads to swelling of the Sabarmati river in 2017. In order to determine extent of Inundation, Hydrodynamic Model HEC-RAS(5.0.6) with Arc GIS was used. Various scenarios were run with HEC-RAS to study the impact of flow simulation on flood inundation(with & without riverfront project). The simulated flood depths have been compared with actual depths obtained at gauging station, which were collected from Government authorities. Ultimately, the analysis was used to create maps for different return periods with RAS Mapper and ArcMap that visually show the reach of the floodplains, illustrating the affected areas. Results demonstrate the usefulness of  modelling system to predict the extent of flood inundation and thus support analyses of management strategies to deal with risk associated with infrastructure in an urban setting.</p>

Piezometric Assessment for Salinity in Multi Aquifer System in Dharoi Command Area, Gujarat

Our earlier study carried out in Dharoi command area in Sabarmati River Basin, in India, defined the sensitive parameters to address the problem of water logging and salinity in the shallow aquifer, contribution of multi-aquifer system in making the scenario complex, was thus evident. Therefore, extension of the study by analyzing the piezometric data of complex lithological setup is attempted in this paper. The present paper establishes and discusses the relationships of various depth wise aquifer zones with the help of the seasonal piezometric heads and TDS values, analyzed as tracers.

Flood Frequency Analysis in Sabarmati River basin and Estimation of Peak Discharge under Climate Change Scenario

Due to climate change, there is an increased/decreased frequency of peak flood discharge in river and streams. The most important concern of planning is to safe passing of the extreme flood discharge influenced by extreme climatic changes. It is a concern for planning for the storage capacity to safely store extreme discharge/inflow of the river. In this paper, probability theories and statistics for flood frequency factor (K) are applied and based on the results; it is found that the Extreme value model results in to a best model for frequency factor K, as it is yielding the minimum relative error. Using the frequency factor, the flood frequency analysis for peak flood is carried out for climate change scenario/Advance scenario. The peak discharge in advance scenario is more as compare to the base line scenario at most of the stations except three stations located on the south-east of the Sabarmati river basin.