How to quench wa­ter­stressed Chen­nai’s thirst

Governance Now - - INTERVIEW - shivani@gov­er­nan­

For the past two years Chen­nai has been fac­ing an acute wa­ter cri­sis. From de­sali­na­tion plants to recycling wa­ter, the city is do­ing ev­ery­thing to im­prove the sit­u­a­tion. In an in­ter­view with Shivani Chaturvedi, Chen­nai wa­ter author­ity MD V Arun Roy ex­plains the mea­sures un­der­way to tackle the peren­nial cri­sis.

What are the gov­ern­ment’s plans to im­prove the wa­ter sit­u­a­tion in Chen­nai?

chen­nai never had ad­e­quate wa­ter. it has al­ways been a wa­ter-stressed city. as early as in the 1940s, the mayor of chen­nai had stated: “What kind of city we are in as it is a wa­ter starved city!”

The de­mand for wa­ter in chen­nai is about 1,100 mil­lion litres per day (mld). at the best of times, we used to sup­ply about 830 mld. now with all our reser­voirs run­ning dry we are pro­gres­sively go­ing down and at present we sup­ply about 470 mld. and this we are man­ag­ing be­cause of things like de­sali­na­tion plants. We have the high­est in­stalled ca­pac­ity of de­sali­na­tion plants.

at present, chen­nai metro Wa­ter has two de­sali­na­tion plants in min­jur and nem­meli with a ca­pac­ity of 100 mld each. out of 470 mld, about 40 per­cent of wa­ter comes from de­sali­na­tion plants. Then there are cer­tain mea­sures which only chen­nai has tried such as hir­ing bore-wells from farm­ers in the nearby dis­tricts and car­ry­ing wa­ter to the city. about 100 mil­lion litres come from agri­cul­tural lands. The other thing that chen­nai has tried is util­is­ing aban­doned min­ing quar­ries that have lots of wa­ter; this proved to be a great as­set. chen­nai is also get­ting wa­ter from neyveli re­gion and it has a good aquifer, plus there is neyveli mines from where lot of wa­ter comes out, and is be­ing pumped to chen­nai.

The only per­ma­nent so­lu­tion which the gov­ern­ment is do­ing is wa­ter recycling. But be­fore com­ing to recycling i would talk about wa­ter recharge, a method in which chen­nai has been a pioneer. as early as 2001 we changed our build­ing rules, mak­ing rain wa­ter har­vest­ing struc­tures com­pul­sory in all build­ings. ever since, for any new build­ing to get plan ap­proval it has to have the rain wa­ter har­vest­ing struc­ture. and this is some­thing which is more or less com­plied with be­cause peo­ple are fairly aware that they need to have wa­ter for their own use. Re­cently, an in­de­pen­dent ngo, Rain cen­tre, did a sur­vey on rain wa­ter har­vest­ing struc­tures in chen­nai and they found about 60 per­cent of the build­ings are com­ply­ing with it. How­ever, how much wa­ter one can recharge de­pends on the rain­fall the city gets. last north­east mon­soon was the worst in 140 years, so the city hardly re­ceived any rain­fall.

Is there any so­lu­tion for this acute wa­ter prob­lem?

There are only two per­ma­nent so­lu­tions – one is wa­ter recycling, we have to get into recycling in a big way. ev­ery com­pound should have its own recycling sys­tem where grey­wa­ter and black­wa­ter (sewage) is sep­a­rate. Black­wa­ter of course goes into the sewage sys­tem but today even grey­wa­ter goes into the sewage sys­tem. Grey­wa­ter should be re­cy­cled and used for gar­den­ing and flush­ing pur­pose. In fact, in 2001 our build­ing rules said that with recharg­ing there should be recycling sys­tems also in all the special and multi-storeyed build­ings. But the

sec­ond part never re­ally got en­forced.

What is Chen­nai do­ing to get its wa­ter back?

From april 2017 we have made it com­pul­sory for all ‘special build­ings’ (ground floor plus two) and multi-storeyed build­ings that have ap­plied for wa­ter or sewage con­nec­tion to have recycling mech­a­nisms. now none of these new build­ings are get­ting con­nec­tions un­less they have recycling mech­a­nism, whether they use it or not is a dif­fer­ent is­sue. At least we are en­forc­ing that they are given plumb­ing.

The other thing be­ing done for recycling is that two ter­tiary treat­ment re­verse os­mo­sis (TTRO) plants with a com­bined ca­pac­ity to treat 90 mld sewage are un­der con­struc­tion. at present, we treat sewage wa­ter and pump it into wa­ter bod­ies like cooum or Buck­ing­ham canal. That is called se­condary treat­ment. Ter­tiary treat­ment goes through ul­tra-thin mem­brane, which pu­ri­fies wa­ter fur­ther and then re­verse os­mo­sis is done. So it is ac­tu­ally potable wa­ter. This is what Sin­ga­pore calls new wa­ter. They mix 30 per­cent of this new wa­ter with the old wa­ter. We are try­ing to pro­duce 90 mil­lion litres of such wa­ter and sup­ply it to in­dus­tries. For both projects ten­ders are awarded and work has started on two lo­ca­tions – Koy­ambedu in west Chen­nai and Ko­dun­gaiyur in north Chen­nai. This wa­ter will be bet­ter than the wa­ter we are sup­ply­ing in pipes as it is Ro wa­ter. at present, we are look­ing it as an in­dus­trial sup­ply project. For ob­vi­ous rea­sons we don’t ex­pect peo­ple to use it as drink­ing wa­ter, but if they are will­ing we will have to lay sep­a­rate pipe for it, which is go­ing to be too ex­pen­sive. The cost of one project is ₹394 crore and the other costs ₹334 crore.

an­other so­lu­tion is to have more de­sali­na­tion plants. as of now chen­nai is get­ting sup­ply from 200 mld ca­pac­ity de­sali­na­tion plants and the process of cre­at­ing an­other 550 mld ca­pac­ity is un­der­way.

The fourth strat­egy is to re­store our wa­ter bod­ies. Tamil nadu has sev­eral ir­ri­ga­tion tanks. as land got aban­doned for ur­ban­i­sa­tion these tanks got en­croached and they no longer serve the pur­pose. There is a need to re­claim these tanks and im­prove them and re­store their sup­ply chan­nels. They act as ad­di­tional stor­age struc­tures.

To start with chen­nai cor­po­ra­tion and Tamil nadu ur­ban in­fras­truc­ture and fi­nan­cial ser­vices lim­ited (TNUIFSL) have pre­pared a de­tailed project re­port for 32 small tanks within and around the city. Some of these tanks are al­ready en­croached while the oth­ers are dead, in the sense that their flow chan­nels are en­croached or blocked. Plus, the Tamil nadu wa­ter sup­ply and drainage (TWAD) board pre­pared a ₹400 crore project for re­ha­bil­i­tat­ing tanks out­side chen­nai. also, the state gov­ern­ment has a scheme called sus­tain­able wa­ter se­cu­rity mis­sion.

at some places evic­tion of en­croach­ment of wa­ter bod­ies may not be pos­si­ble. How­ever, restora­tion of the 32 iden­ti­fied tanks is not that prob­lem­atic. Within cities there are tanks that are en­croached. So we have to take a call if we want to evict the en­croach­ment and carry out the wa­ter tanks re­hab ex­er­cise or re­claim what­ever is avail­able. Some of these old wa­ter bod­ies have been oc­cu­pied be­cause the gov­ern­ment it­self had al­lowed lay­outs to be de­vel­oped in those ar­eas. many such con­struc­tions have taken place un­der the gov­ern­ment’s Eri (wa­ter bod­ies) scheme.

What are the chal­lenges in the ex­er­cise of get­ting wa­ter back?

There are sev­eral. Things like recycling may not cost much, but we have to work with peo­ple so bring­ing be­havioural change may be a chal­lenge. en­croached wa­ter bod­ies and un­planned de­vel­op­ment of the city are other chal­lenges. Funds are a huge con­straint. in­stal­la­tion of de­sali­na­tion plants is an ex­pen­sive process. TTRO again is ex­pen­sive, as far as we are sell­ing it to in­dus­tries and they are buy­ing it at a cost it is fine. But if we are go­ing to do­mes­tic sup­ply we can­not charge them like that. also, avail­abil­ity of land is an is­sue.

Fur­ther, reg­u­la­tion is an is­sue. For ex­am­ple, coastal reg­u­la­tion zone (CRZ) norms are very strict. So to get clear­ance for a 150 mld de­sali­na­tion plant the process has been on for al­most a year now. We are asked to sub­mit var­i­ous re­ports.

many think that we wasted a lot of wa­ter dur­ing the 2015 floods by al­low­ing it to flow into the sea. In a way it is cor­rect. But at the same time we have to un­der­stand that we got a month’s rain in just two days. no reser­voir could have stored that amount of wa­ter.

Ma­jor­ity of the sewage goes un­treated into wa­ter bod­ies. How does Chen­nai aim to tackle this is­sue con­sid­er­ing it is al­ready fac­ing a se­vere wa­ter cri­sis and wa­ter bod­ies are get­ting con­tam­i­nated?

Sewage does goes into wa­ter bod­ies in mul­ti­ple ways. it hap­pens mostly be­cause peo­ple rather than tak­ing a sewage con­nec­tion just con­nect it to the storm wa­ter drains, as many of the houses are un­ap­proved. This way they don’t have to pay any­thing. also, there are lo­cal­i­ties where pop­u­la­tion would have sud­denly gone up and sewage lines are not strong, peo­ple make lo­cal ar­range­ments and wa­ter is di­verted to storm wa­ter drains. This is a solv­able prob­lem. We know these places and are tak­ing cor­rec­tive mea­sures un­der var­i­ous schemes. How­ever, keep­ing pace with rapid ur­ban­i­sa­tion is not easy. and in chen­nai the sewage prob­lem is man­age­able as our treat­ment ca­pac­ity is bet­ter.

“As early as 2001 we changed our build­ing rules mak­ing rain wa­ter har­vest­ing struc­tures com­pul­sory in all build­ings. Ever since, for any new build­ing to get the plan ap­proval it has to have rain wa­ter har­vest­ing struc­ture.”

Shivani chaturvedi

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