Project K-100: re-visioning of Koramangala valley drainage system

An excerpt from a New Indian Express report of yesterday, read as @ Birds can be seen flocking to Bellandur lake and its surroundings for the third consecutive day. The lake which was in news for all the wrong reasons - being choked with sewage, flooding, frothing and even on fire, is now becoming a photographers delight. For the full text of the report, click here.

 

So, the work taken up on the lake proper, as directed by NGT, is apparently beginning to take effect, after all - good to know! But, this is very likely the result of the dilution of the sewage in-flow because of the torrential rains over the past few weeks. Not sure if the bird-life will continue when the in-flow reverts to "pure sewage", once the monsoons recede. 

 

At the presentation made on the 11th Oct, Mr Naresh Narasimhan had claimed that the sewage flow in the SWD, upstream of the Intermediate pumping station (IPS), at the National Games Village (NGV), had reduced hugely, since the commissioning of the station last month. However, logic suggests that all that it could have achieved perhaps is speedier flow, since the work on the pipeline linking the IPS and the 150 MLD STP (at Belur Nagasandra complex) is far from complete. The most difficult part of taking it below the footings of three bridges across the SWD (check the red route marked out in the map accessible here) is yet to start.

 

In Mr Naresh Narasimhan's presentation, a sewage trunk line was shown running alongside (or through) the entire length of the SWD. One wonders if this is the case in Seoul too (on which the K-100 project is largely modelled). If yes, how are they checking mixing of sewage with storm water - by having a number of de-centralised STP's? If not, where are their sewage lines laid, and what kind of an arrangement do they have for treatment?

 

All in all, a massive and costly project. But, at the end of it all (say 3 to 5 years), if we can have Bellandur lake, and the SWD's (restored as Rajakaluve's), nurturing flora and fauna year-round, like we got a glimpse of presently, perhaps it will be worth the effort.

 

And, this is supposed to be a pilot. Based on the learnings, restorations of the Chellagatta (check here for it's boxed-up state), Rishabhavati, and Hebbal valley drainage systems too are to follow. We live on hope - pray it actualises! 

 

PS: Equally exciting have been similar efforts of rejuvenation 

Extensive damage had been done to the rivers by the earlier exercises, and now, teams of local architects, in both the cities, have come together to undo the damage, and take it beyond, along sustainable routes.

 

I learned of these while attending some of the webinars, part of a series put together by INHAF ( https://www.inhaf.org/ - headed amongst others by the renowned, Gujarat based architect, Sri Kirtee Shah).

 

"The civic body should invest in getting all houses connected to sewer lines. The money spent on sewage diversion channels is bound to go to waste as no storm water drain is free from sewage” professor Inayathulla M, professor of water resources engineering at Bangalore University said. According to him, the only solution is to is to identify buildings that are letting sewage into the drain and ensure all the sewage flows into treatment plants instead.

 

The above are excerpts from a 24th Sept report, headlined "What the muck", in the "Bangalore Mirror". For the full text, click here. 

 

While the pictures in the report pertain to the K-100 project, from the text it is not clear if the learned professor is indeed referring to this project. Well, I had mentioned in my opening post itself as "Best part is the buy in managed from as varied stake-holder groups as Rotary, ESG, IISc, KSPCB, BWSSB, experts from among retired bureaucracy etc". So, has the buy in from stakeholders not been complete? 

 

Prof Inayathulla's name didn't appear in the list of invitees to the earlier webinars. He has made some valid points, and the chief project proponents would perhaps do well to address his concerns.

 

Now, from what I learned subsequently, the project envisages re-laying of a high capacity sewage main from the starting point (near Chikka-Lalbag) upto the ISPS (Intermediate Sewage Pumping Station) near Games Village (Koramangala), below the SWD, replacing the old sewage main. One 5 MLD STP is to be set-up close to the starting point, part of the treated water from which will be let into the SWD. Apart from that, sewage from areas along the route will be channeled to the sewage main, all of it ending up in the jack-well at the ISPS through gravity flow. From the ISPS, it'll all be pumped to the STP complex at Belur-Nagasandra (at the edge of Bellandur lake) through the newly laid 6ft dia pipes.

 

The sewage from areas West of Koramangala IRR (Itermediate Ring Road) will now be diverted to the ISPS jack-well, through a sub-main being freshly laid. Earlier all of this, along with the sewage from the rest of Koramangala too, was being channelled to the jack-well at the Jakkasandra/ Agara Sewage pumping station, through the sub-main along the 80 ft road. The sub-main was getting choked, and hence the decision to divert half the load to the ISPS jack-well. Now, only the sewage from East of the IRR will be channelled to the Jakkasandra/ Agara pumping station (The line from there to the STP complex already exists). A fresh sub-main has been laid for the purpose between SonyWorld junction and Wipro/ KamalBakery junction. At Wipro junction, it will connect to the existing sewage sub-main leading to the Jakkasandra/ Agara pumping station. The link at Wipro junction is proving a major challenge, since it has also to incorporate the sewage line coming in (below the Seva-in-action bridge) from ST bed layout, apart from having to negotiate the BBMP's "parallel drain", all at some 30 ft below GL. The job is on currently.

 

Quite as Prof Inayathulla has stated, the efficacy of it will all depend on ensuring all the dwellings along the route are connected to the sewage lines in each of the areas, and the flow from them to the sewage main remains unhindered. Unless that happens, water (sewage here) which finds its own level, will flow naturally to the lowest point - the lake. And, the entire exercise will land up as a colossal waste.

 

The ultimate answer, whatever, will have to be de-cetralised STP's, perhaps one (or more) for each ward. The earlier we realise that the better.

 

PS: All of the above are based on what I have gathered from various sources, and subject to correction, if authenticated information is made available to me.