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Reply to CWC response on SANDRP’s article on CWC’s flood forecasting in NE India

On Aug 5, 2018, SANDRP had uploaded blog[i] titled: “Overview of CWC’s Flood Monitoring & Forecasting in North East India”. CWC posted its 3-page reply to it around 7 pm on Aug 7, 2018.

Firstly, we welcome CWC’s reply to SANDRP blog. Here some responses to the content of what CWC has replied.

Here are screen shots of CWC’s response from twitter.

Sikkim CWC has explained, for non functioning of its flood monitoring and forecasting sites in Sikkim, that till 2017, “There was no Flood Forecasting (FF) setup in in Sikkim up to 2017.” So the work of setting up 5 inflow and 3 level forecasting sites in Sikkim has just started and it will take 3-4 years to gather sufficient data to set up forecasting models for level forecasting sites. For inflow forecasting sites too it will take some years to set up rainfall runoff forecasts. One only wishes CWC would have stated this on its FF website and also its in its Standard Operating Procedure for flood forecasting in 2018, where they do list the sites, but do not provide any of this background information.

Inactive sites in other NE states and W Bengal CWC explains that these sites “are operated under DWRIS/ IWRD and data collected are entered on daily basis”. CWC also says that data frequency is much lower for these sites “from the data requirements for Flood Forecasting (FF) activity”. Firstly, CWC’s contention that “data collected are entered on daily basis” is incorrect for many sites when we see the snapshots of CWC’s flood forecasting website below, showing that either no data is entered or outdated, 2015 data is shown.

Screen shot (12 noon on Aug 8, 2018) of CWC FF website for Myntdu II Power House site in Meghalaya showing no data
Screenshot (12 noon, Aug 8, 2018) of CWC FF website for Myntdu Leshka Dam in Meghalaya, showing there is no data
Screen shot (12 noon, Aug 8, 2018) of CWC FF website for Bailey Bridge Tuipal in Mizoram showing outdated, old information of Aug 13, 2015

Secondly, if that is the case, why does CWC not mention this on its FF website, that this is the practice being followed for these sites? Why give an illusion of so many sites, when they are not even properly monitored? Why did the CWC not mention this in its SOP document for 2018 flood forecasting where it does mention 700 additional monitoring sites.

Jaldhaka site NH 31 in W Bengal CWC claims the hydrograph is active, but see below the hydrograph downloaded from CWC site at 12 noon on Aug 8, 2018, it shows that hydrograph is blank and there is no hourly data.

Screen shot (12 noon, Aug 8 2018) of CWC FF website showing the inactive hydrograph of NH 31 site on Jaldhaka river in W Bengal in Brahmaputra basin

Kailashahar, Tripura CWC says there are two different locations, operated by two difference divisions for the two sites with the same name. Firstly, the two locations do not seem far apart considering that they show the same HFL level, both showing hourly reading, while as per CWC’s contention, the DWRIS is supposed to take only daily and not hourly reading, CWC is thus contradicting itself. More shocking is the fact that the levels are so different for the two close by location sites! CWC does not explain why these difference are there and how far apart are two locations with same HFL? Also, why is CWC giving these two sites if the two locations have same HFL and close by locations, particularly when they give contradictory readings?

CWC accepts no FF sites in Nagaland, Manipur, Mizoram and Meghalaya While CWC accepts this reality, its defense is untenable: There is no demand from the states. If the states have flood prone areas, than CWC, the sole FF agency in India, must discuss with these states the need to set up FF sites.

Sorry, this is untenable It’s second argument, “in case of majority of short length rivers in these states, travel time is generally not sufficient for issue of a worthwhile and useful Flood Forecast by conventional method of formulating co-relations between a Base Station and a FF Station”, raises a number of issue.

  • Firstly, this means that CWC is still using for its flood forecasting, “conventional method of formulating co-relations between a Base Station and a FF Station”. Why is CWC also not using the IMD’s actual rainfall data in the catchment of the specific site and also the short term rainfall forecasts, to make more advance flood forecast and warning?
  • Secondly, the short travel time excuse is strange, in fact in such rivers, there is even more urgency and necessity to provide flood forecasting.
  • In fact, CWC had used this excuse in the past too, for not having flood forecasting sites in Uttarakhand (post June 2013 flood disaster) and Jammu & Kashmir (post Sept 2014 flood disaster), but subsequently agreed to add some flood forecasting in these states, though they remain inadequate.
  • Moreover, not all rivers in these four states are short length rivers.

More sites in Tripura We are glad that CWC has accepted our contention that more flood forecasting sites are required in Tripura and have said that process has started to add them.

URGENT need to add inflow forecasting at all dams and level forecasting in downstream of dams As underlined by the ongoing controversy about Doyang Dam in Nagaland creating flood disaster in downstream Golaghat in Assam starting early August 2018, CWC needs to add all existing dams (e.g. Ranganadi, Doyang, Loktak, Dumbur) in its inflow forecasting and downstream areas of these dams in its level forecasting on urgent basis.

We assume CWC accepts the rest of our recommendations in our blog, since CWC has not responded to them. We again welcome CWC response. We would look forward to CWC’s response to reply, to our other regional blogs on CWC’s flood forecasting, of which one for North India is already published[ii] and to our flood related blogs this year where CWC’s flood forecasting gets mentioned[iii].

SANDRP (ht.sandrp@gmail.com)


[i] https://sandrp.in/2018/08/05/overview-of-cwcs-flood-monitoring-forecasting-in-north-east-india/

[ii] https://sandrp.in/2018/08/03/overview-of-cwc-flood-forecasting-sites-north-india/

[iii] See for example: 1. https://sandrp.in/2018/08/07/role-of-doyang-dam-in-bringing-unprecedented-floods-in-golaghat/

  1. https://sandrp.in/2018/07/24/cauvery-is-facing-very-serious-flood-risk-but-cwc-is-in-slumber/
  2. https://sandrp.in/2018/07/28/floods-flood-monitoring-in-yamuna-july-2018/
  3. https://sandrp.in/2018/08/03/will-sluggish-farakka-again-create-prolonged-floods-along-ganga-in-bihar/

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