Table 4 Total Estimate of Water Requirement for the projected population of CMA for various years and ultimately for 2026

Table 4 Total Estimate of Water Requirement for the projected population of CMA for various years and ultimately for 2026

Total Estimate of Water Requirement (CMA)

Chennai Metropolitan Area(CMA)

Year

2011 2016 2021 2026

1. Population in lakhs 88 100 112 126 2. Resident population's water use in MLD

a) Scenario I 1165 1284 1431 1606 b) Scenario II 938 1035 1154 1296 c) Scenario III 762 838 933 1046 3. Water requirements in MLD for non-residential uses such as offices, commercial, and industrial properties, as well as other places of employment, education, and so on.

Scenario I 349 385 429 482

Scenario II 235 259 289 324

Scenario III 152 168 187 295

4. Industrial Use

Scenario I 116 128 143 161

Scenario II 94 103 115 130

Scenario III 76 84 93 105

5. Total Requirement Scenario I 1631 1797 2003 2248

Scenario II 1267 1397 1558 1750

Scenario III 990 1090 1213 1360

Source: Master Plan For CMA 2026

There are 1635 MLD of water available from all current sources, including desalination, and 185 MLD of recovered sewage water in the overall water allotment. If more recycled water becomes accessible, the burden on potable water will be alleviated. The implementation of conservation and management methods, such as local grey water recycling for toilet flushing, will reduce the need for extra potable water and hence the need to explore other sources, such as increased desalination of water. It will also improve the water sector's long-term viability while reducing the negative environmental effect of consumed water.

The Chennai system's current sewage treatment capacity is 481 MLD, and recycling might provide at least 300-400 MLD, which is more than enough to fulfil not just the 2026 industry requirement, but also any future industrial demand in terms of quantity.

A water map outlining all potential surface and groundwater sources is recommended in the plan. Desilting of existing lakes for rain/flood water storage and monsoon run-off capture could be part of the Integrated Water Management Plan. The concept of zero run-off drainage should be used with retention ponds, sediment traps, and balancing lakes.

The plan calls for the rehabilitation and refurbishment of around 320 surface tanks to supplement local potable water supplies.The Development Regulations include parameters for water conservation and improved management, as well as parameters for installing sanitation and recycling in new developments.

3 . 5 . 3 S O L I D W A S T E M A N A G E M E N T

The MSW (Handling and Management) Rules, 2000, and the rules of the Central Act pertaining to solid waste management shall be rigorously implemented by the appropriate authorities within CMA. Existing landfill sites must undergo an environmental evaluation, and appropriate actions must be done to enhance them. Solid waste management is the area where residents and the private sector must collaborate to maintain city health and safety. It is necessary to raise awareness about the importance of source separation and differential disposal.

Residents' associations and non-governmental organisations (NGOs) have attempted to reduce the burden on local governments by segregating solid waste, composting, and recycling locally, but these efforts have not had a long-term impact due to a variety of factors, including a lack of support from local governments. Local governments can tax big rubbish generators like hotels, ceremony halls, marketplaces, and commercial areas under the "Polluters Pay" principle.To reduce human touch, mechanical garbage management such as auto-tippers, tricycles, and push carts might be promoted. Because solid waste management is getting more complicated, local governments should improve their technical and managerial abilities, such as project development, finance, and staff monitoring and supervision.

Following the full ERM analysis, a distinct solid waste management action plan will be necessary to be developed with the major stakeholders, including people and the private sector. As a follow-up to the ERM (Environment resource management) Master Plan, a

complete solid waste management Action Plan must be developed, taking into account the mechanisms to be implemented for waste segregation at the source.Using local and neighbourhood composting and recycling facilities to reduce the amount of waste that must be processed at landfills.Establishing a number of decentralised sanitary landfill facilities in the area to be shared with local governments. Establishing secure e-waste and construction debris recycling facilities.Establishing a scientific solid waste management education and awareness programme for children, youth, and residents.

Incentives for the private sector to participate in the reduction, segregation, transportation, recycling, and final disposal of all sorts of solid waste.The particular responsibilities that will be assigned to stakeholders in the plan's implementation.The Plan specifies current landfill sites as well as new disposal sites suggested by municipal organisations, as well as restrictions on residential and commercial growth in the area. The Plan also suggests that the TNPCB strictly enforce the statutory standards governing solid waste management, biomedical waste, and other hazardous and non-hazardous wastes.(Plans, 2008)

3.5. 4 M A C R O D R A I N A G E S Y S T E M I N C M A

Despite the territory's extensive drainage systems (158 km) and water storage systems (tanks and reservoirs), the region, notably the City, is prone to yearly floods of constructed and inhabited areas.According to historical records, heavy rain combined with cyclonic activity caused disastrous flooding in Chennai in 1943, 1978, 1985, 2002, and 2005. The failure of major rivers and other drainage systems was determined to be the root cause of these devastating flooding disasters.

The CMDA's land use plan defines all of the significant macro drainage features and specifies the conservation area's size.

Lakes and water bodies must be safeguarded from encroachment, and existing encroachments must be removed in order to restore the water bodies to their natural state.The land use plan highlights the essential regions prone to yearly floods, allowing local governments to work with the PWD to implement remedial measures.The land use plan also defines locations where development other than that which is fit for use as open space must be forbidden or severely limited. The Pallikkaranai marsh and the Redhills catchment region are two examples. The Development Regulations provide guidelines for protecting streams and water bodies from unfavourable development. The Plan calls for the execution of the MMFR/SWD

Master Plan Study Report's recommendations.A micro drainage strategy for each local body can be created by the local body in conjunction with PWD and implemented within a time

range.

3 . 6 C H E N N A I W A T E R C R I S I S A N D L A N D U S E P L A N N I N G

As a result of increased urbanisation, industrialisation, and climate change, many cities throughout the world are experiencing acute water shortages.In the instance of Chennai, India, the city awoke in June 2019 to the tragic news that all of the city's major water reservoirs had dried up.

This catastrophe was unexpected because the city and its environs have long been home to several water bodies and rivers, as well as a canal, making it a one-of-a-kind metropolis with a richness of water distribution systems and proper drainage. Chennai has the potential to be a water-resistant metropolis, but it is now experiencing a water shortage.

Chennai is noted for its centuries-old indigenous water-body system known as eri.Eries were seasonal water sources that created an interconnected irrigation system for the region, along with their networked drainage systems. The agriculture industry was completely reliant on this system, which operated flawlessly for generations until it was phased out in the 1960s.

The city of Chennai's forced development resulted in the disappearance of water bodies due to in-filling. State institutions such as the Chennai Metropolitan Development Authority (CMDA) and Tamil Nadu Housing Board (TNHB) were involved in developing official land-allocation plans. To supply space for houses, infrastructure, and institutions, vast swaths of aquatic bodies were filled with garbage, often at great expense. To supply space for houses, infrastructure, and institutions, vast swaths of aquatic bodies were filled with garbage, often at great expense.

An environmental NGO contested one of these cases in 1993, and the government's justification was that the lakes were "abandoned and unusable for groundwater recharge," according to the government's response(Coelho, 2020).

Figure depicts how uncontrolled growth in the built-up region has resulted in a drop in the size of water bodies in the Chennai Metropolitan Area during the last three decades.

Chennai is a seaside city, and much of the city's growth takes place along the water's edge. Residential neighbourhoods were built close to the shore, which offered both advantages and