Published on Nov 30, 2023
The steady increase of urban population and the possible effects of climate change may adversely affect the amount of water available and existing water supply systems. We are in need of a climate resilient environment or management. As a result, a high priority is given to the study of alternative water service options such as storm water, rain water harvesting and waste water recycling along with centralised systems. In this type of systems, water is supplied via a centralised water supply system in combination with decentralised water supply options such as rainwater-storm water harvesting & waste water reuse. This combination of centralised-decentralised water supply systems is termed as Hybrid water supply system (WSS). Such hybrid WSS can offer the potential for increased urban water system security and sustainability by reducing net urban water use, freeing up water supplies for other uses and reducing resource consumption because of reduced conveyance requirements and absence of the need to treat all water to the same high standards.
This paper demonstrates about the water harvesting through surface water bodies and treatment and reuse of the sewage. The paper gives an ideology to adopt decentralised WSS options in combination with centralised system to aid with meeting the water demand as well as flood mitigation and stream health restoration. This paper also provides a framework to understand the interaction between the components (centralised and decentralised system) of hybrid system. The framework depends on understanding the existing local conditions and developing a solution.
Keywords : hybrid system, Jakkur Sampigehalli Lake
The study area chosen for the present study is Jakkur Sampigehalli Lake, Hebbal Valley Bangalore as an alternate source for existing Cauvery Water Supply.
This study was undertaken to assess the quantum of water available in the Jakkur Lake region to meet the domestic demand.
The study brings out that there is sufficient water available in the region, but to understand the inability or ineffectiveness of the local administrators to sustainably manage the water resources in the region.
Sufficient water is available to meet everyone’s requirement, provided;
Water harvesting is undertaken through surface water bodies; this requires rejuvenation of lakes and re-establishment of interconnectivity; harvesting of rainwater (at decentralized levels), treatment;
Treatment and reuse of sewage for multiple demands.
GIS application provides functions for development and preparation of accurate spatial digital information as input into data for the network design optimization model, which included network layout, connectivity, pipe characteristics and cost, pressure gradients, demand patterns, cost analysis, network routing and allocation. The model illustrates, the methodology of creating WDN(Water Distribution Network) through GIS software, it is a set of Geo-database model objects with relations and behaviours for distribution network made of object classes, layers includes (polygons, lines and points).
Flow distribution can be calculated in branched networks by applying flow conversation equations in the nodes of the network. The procedure consists of generating two opposite extreme flow distribution scenarios that satisfy the nodal flow conservation equations. The flow distribution can be managed using the EPANET software.
It is essential to design a framework to evaluate Hybrid Water Supply System (WSS). The following steps may be considered for designing of framework:
1. Understanding the local conditions and current system capacity:
2. Establishing specific objectives:
3. Setting the evaluation criteria
4. Water supply servicing options
5. Developing scenarios.
6. Analysis of scenarios.
7. Evaluate scenarios
8. Preferred scenarios and uncertainty analysis
This study explores the impact of hybrid centralized and decentralized urban water supply systems.
The framework can be used to identify the impacts of Hybrid Water Supply Systems on existing infrastructures
This framework will support further research to assess the impacts of various combinations of hybrid water supply systems on waste water and storm water quantity and quality in various case study locations.
This study reviews an overview of exiting challenges of Bangalore city to meet the water demand.
The study explores the relevance of centralised and decentralised urban water supply systems which are considered to provide a way out to meet the increasing water demand.
The study reviews an overview of hybrid water supply system and its benefits.
The study gives a brief description of decentralised system and its components.
The study provides a methodology of wastewater treatment and tertiary treatment of water for domestic purpose.
To compare the advantages of existing waste-water reuse systems for multiple purposes.
A framework for introducing of hybrid water system is developed. This framework will support further research to assess the impacts of various combinations of hybrid systems in various study locations.
The study provides a solution to water users which are in need of a climate resilient methodology to meet the water demand.
