Im­prac­ti­cal clean-up plan

Down to Earth - - CONSERVATION - Bil­lion litres days

me­tres (cu m) of sludge. Given that earth­movers can dredge a max­i­mum of 1 mil­lion cu m of sludge a day, it would take four years to com­plete the task. For trans­port­ing this amount,220,000 trucks,each with a ca­pac­ity of 25 tonnes,need to be pressed into ac­tion.

Be­sides, de-silt­ing is not a sim­ple process, warns Hy­der­abad-based en­vi­ron­men­tal­ist K P Reddy. It is not fea­si­ble to de­silt im­me­di­ately af­ter emp­ty­ing the lake as high mois­ture con­tent of the sludge would not al­low move­ment of earth-movers.Since phys­i­cal and chem­i­cal com­po­si­tion of dredged ma­te­rial is com­plex,Reddy sug­gests that the gov­ern­ment should con­duct sci­en­tific stud­ies about its prop­er­ties,iden­tify sta­bil­i­sa­tion mech­a­nism, and then spec­ify the mode of dis­posal.If dis­posed of with­out protective lining, haz­ardous wastes and fae­cal mat­ters present in the sludge would con­tam­i­nate sur­face wa­ter and ground­wa­ter.

But such a sce­nario seems un­avoid­able as there is lit­tle co­or­di­na­tion be­tween ghmc, re­spon­si­ble for keep­ing the lake wa­ter clean, and hmda, which works on catch­ment restora­tion. The Su­per­in­ten­dent En­gi­neer (Lakes) of hmda, B L N Reddy says ghmc has not kept his depart­ment in­formed about trucks, each of 25 tonne ca­pac­ity, would be needed to re­move 4.4 mil­lion cu m of sludge over four years

of wa­ter needs to be pumped out. For this, wa­ter has to be re­moved round-the-clock for 50 days us­ing pumps of 1,800 HP ca­pac­ity the restora­tion plan of Hus­sain­sagar.

Shailen­dra Joshi, prin­ci­pal sec­re­tary of the Ir­ri­ga­tion Depart­ment,cites an­other rea­son why Rao’s dream project would fall flat. Fill­ing the lake only with rain­wa­ter is im­pos­si­ble as most of the runoff gets ob­structed due to poor drainage net­work in the catch­ment. Joshi’s state­ments are cor­rob­o­rated by a study by Ram­mo­han Reddy of Jawa­har­lal Nehru Tech­ni­cal Uni­ver­sity (jntu), Hy­der­abad, who found that the lake’s sur­round­ing area does not have a good net­work of stormwa­ter drains. Even if hmda re­vives the en­tire catch­ment and redi­rects the runoff to­wards the lake, Down To Earth’s as­sess­ment shows it will take 10 days of con­tin­u­ous rain­fall in the mon­soon to fill up. But this is less likely as the re­gion is in­creas­ingly suf­fer­ing from rain­fall deficit and re­cur­rent droughts.

More­over,chief min­is­ter Rao’s dream to re­store the health of the lake is likely to re­main just that—a dream—un­less the au­thor­i­ties man­age the flow of mu­nic­i­pal solid waste from sur­round­ing res­i­den­tial and industrial ar­eas (see ‘Dy­ing lake’). Ev­ery day, 78 mil­lion litres of sewage and 15 mil­lion litres of industrial ef­flu­ents flow into the lake through four drains, as per Andhra Pradesh

of con­tin­u­ous rain­fall in the mon­soon can re­fill the lake. This is less likely as the re­gion has lately faced rain­fall deficit, drought Pol­lu­tion Con­trol Board (appcb) data of 2012-13. The two sewage treat­ment plants (stps) near the lake are in­suf­fi­cient to han­dle the waste­water load,say soul ac­tivists.

So,in­stead of un­der­tak­ing an am­bi­tious project,the need of the hour is to un­der­stand what plagues Hus­sain­sagar. In last three decades, the lake has shrunk by 40 per cent, pri­mar­ily be­cause of en­croach­ment by both public and pri­vate agen­cies, ac­cord­ing to non-profit Fo­rum for a Bet­ter Hy­der­abad.To save the lake,con­ser­va­tion­ists,in­clud­ing K L Vyas,con­venor of Save the Lake Cam­paign, have moved the High Court of Andhra Pradesh sev­eral times, but to lit­tle avail.

In 2000, the Hy­der­abad Ur­ban Devel­op­ment Author­ity is­sued a no­ti­fi­ca­tion to pro­tect the lake, but there have been in­stances where it gave in to the real es­tate lobby and al­lowed res­i­den­tial colonies on the catch­ment.In 2006,hmda ini­ti­ated Hus­sain­sagar Lake and Catch­ment Area Im­prove­ment project and set up stps and waste­water in­ter­cep­tion and di­ver­sion struc­tures. It also in­stalled foun­tains to aer­ate the lake to im­prove its wa­ter qual­ity.But th­ese mea­sures are ly­ing de­funct.Maybe, Rao should re­visit th­ese un­fin­ished plans first.

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