Apurba Gupta

Genetic algorithm for optimization of water distribution systems

Abstract A methodology based on genetic algorithm has been developed for lower cost design of new, and augmentation of existing water distribution networks. The results have been compared with those of non-linear programming technique through application to several case studies. The genetic algorithm results in a lower cost solution. Parameters governing the convergence of the solutions in non-linear and genetic algorithms are also discussed.

Optimization of water distribution system

Abstract An optimization algorithm with recourse to a nonlinear programming technique based on the interior penalty function with Davidon-Fletcher-Powell method, incorporating the graph theoretic approach for analysis of networks, has been developed for design of functional and least-cost water distribution systems with multiple reservoirs. The model has the capability to design a new system as well as to reorganize an existing system. Reorganization of a system becomes necessary due to increased water demand resulting from an increase in population density and enhanced service levels or expansion to the new areas. Further, the hydraulic simulator based on graph theory enables design of all types of systems; viz branched, looped or a combination thereof including nodes with specified fixed energy grades. The software package has been developed for use on an IBM-PC compatible microcomputer. The efficacy of the algorithm has been demonstrated through an example on design of a typical water distribution system.

Estimation and allocation of solid waste to bin through geographical information systems

This study presents a geographical information system (GIS)-based procedure for the precise estimation of solid waste generation, computed using the local population density and income group distribution. Using a triangulated irregular network (TIN) in a GIS environment, the procedure further determines the command area for waste allocation to a particular bin which is generally located so the route slopes towards the collection points for ease of transportation by cart pullers. Computational results of bin location, type, size and the frequency of removal are presented for a typical urban area with known population density, income group distribution, road network and topology.

Hydrodynamic assessment of sewage impact on water quality of Malad Creek, Mumbai, India

The rapid population growth and uncontrolled development in the coastal zone have led to major pollution impacts on creeks, estuarine, and coastal environment. Water quality models are valuable tools to understand the environmental processes for prediction of pollution impacts and evaluate future trends for management. Presently, the Malad creek in west coast of Mumbai receives wastewater and sewage from open drains and partially treated sewage from Malad and Versova treatment plants. The objective of the paper is to assess the environmental quality and estimate the extent of improvement in different parts of the creek by enhancing the collection efficiency and adequate treatment of sewage as well as disposal through ocean outfall. A hydrodynamic and water quality simulation has been carried out for the present condition in the creek and calibrated and validated with two different season data for better representation of the system. Calibrated model has been used to generate future scenarios based on various options. Among scenarios, option of treated effluent diverted to propose outfall and improvement in collection of unorganized flow through sewerage up to 40% and 60% are found most significant for biochemical oxygen demand reduction and increase in dissolved oxygen. Fecal coliform reduction is also found drastically but still very high against standard. To improve the environmental quality of the creek, still upper stretch requires more dilution and flushing due to narrow width and contribution of heavy pollution from open drains.

GIS-based locational analysis of collection bins in municipal solid waste management systems

Solid waste management systems currently receive wide attention, from both economic and environmental planners, because of their complexity during coordination of various management strategies. The efficiency and cost effectiveness of route optimization and disposal site selection depend largely upon the appropriate placement of storage bins and their corresponding command area for waste contribution. The present paper illustrates a geographic information system (GIS) based algorithm for optimal location and number of storage bins, considering p-median constrained model, based on Indian guidelines for Municipal Solid Waste Rules. The algorithm also computes the contributing command area of solid waste to a particular bin, based on the shortest distance, with descending slope for ease in solid waste collection.

Development of GIS-based environmental information system: an Indian scenario

Abstract Ideally, scientists should be able to format, explore, analyse, and visualise data in a simple, powerful and fast application that would seamlessly integrate georeferenced data from a variety of data sources into an intuitive visualisation. The focus of an Environmental Information System is providing environmental information to decision makers, policy planners, scientists and engineers, research workers, etc. which ensures integration of data collection, collation, storage, retrieval and dissemination to all concerned. All such queries should be responded to supplying substantive information in the form of reports. The paper presents an innovative way to utilise the geographic information associated with the environmental data. The stand-alone application is the integration of using ArcObjects Environmental System Research Institute ArcGIS Engine 9.1 and VB.Net. The geographic information system (GIS)-based application, a framework of digital earth in terms of environmental information system provides a user-friendly query interface, which gives information about various environmental parameters in tabular as well as on map display. It also provides the visual interpretation to make further analysis and future decisions at multiple scales, locations and extents. The facility for modifying the map attributes and corresponding databases is integrated to update the information system. Output spatial data are produced in the form of reports using selected fields with display on map.

Quantitative assessment of annual runoff in sub‐catchments using GIS: a case study of the Tapi River Basin, India

The Tapi is a major interstate, westerly flowing river with 14 tributaries, of which the left bank tributaries support large settlements in Maharashtra State. It has been identified as one of the water scarce basins of India. There are many dams and barrages in the basin to store and divert water for agricultural and industrial purposes. This results in low flow and deterioration of water quality in the region particularly in non‐monsoon months. This paper presents the details of a GIS‐based rainfall‐runoff modelling study carried out to assess the runoff flow in the sub‐catchments and at the outlet of the Tapi Basin. Using mean monthly rainfall data at seven gauging stations in the basin, and land use and soil characteristics as reported by the Central Pollution Control Board (CPCB), the annual runoff flow at the watershed outlet was estimated to be 18,814 MCM. A comparison of runoff generated in the sub‐catchments and the observed runoff at Central Water Commission (CWC) monitoring stations is presented. Results of the simulation indicate that the reduced river flows caused by the number of dams/reservoirs constructed upstream are useful as a guideline for the development of environmental flow regulations for rivers and streams in the Tapi Basin.