Wednesday, October 23, 2019  | 23 Safar, 1441 | BETA
Samaa TV
Facebook Twitter Youtube
HOME > Local

Explainer: Flooding of Karachi’s Super Highway near Saadi Town

August 11, 2019
Explainer: Flooding of Karachi’s Super Highway near Saadi Town

The 2016 map shows how the water is obstructed by housing societies at the Northern Bypass.

Karachi’s Super Highway has done the all-important work of connecting the city to the rest of the country since it was commissioned in the early seventies. This is the artery that steadily pumps our exports and imports to Pakistan.

It was built by an Italian company called Salini Impregilo. Initially, it was a single road with two lanes. In 1996, two other lanes were laid so traffic could run two-way. In 2018, the motorway was completed by expanding it to six rows with a separating barrier.


During the construction of the original highway, the planners were careful to factor in hill torrents that ran down the Kirthar Range to cross the road when it rained. Detailed surveys were carried out and waterways were properly siphoned to make way for flooding.


For the last eight to nine years, however, something strange has been happening. When it rains heavily, the hill torrent called Lath River, which originates in Kirthar National Park, inundates the Super Highway at the Northern Bypass interchange near Saadi Town.


The 2016 map shows how the water is obstructed by housing societies at the Northern Bypass.

The raging waters flood the road completely, making it impossible for traffic to pass. It also spreads all through Saadi Town, threatening the lives and properties of its people. The local grid station is flooded and power supplies are cut off. Some people believe that the government has built dams in the mountains, which breach or overflow and cause this flash-flooding.

Fortunately, Google Earth gives us historical images and so you can easily check and compare satellite maps from 1984 to 2016. The maps also come with land surface elevation from the sea and all this helps diagnose this phenomenon.


If you look at satellite images in this case then, you see that the so-called broken dams are not water storage but are actually
retention weirs. Weirs are structures that delay the flow of torrents of water down hills in order to recharge groundwater aquifers. (See diagram). Without them, the flood waters will still run down, just with more speed.

Groundwater dams obstruct the flow of groundwater and store water below ground level and replenish the wells. There are different types of ground water dams also called retention weirs. Image: Freie Universitat Berlin

If you surf the area in Google, the puzzle of the Super Highway flooding can easily be solved. The 1984 imagery shows that the Lath River used to flow down its natural route, which went just beside the Cosy Water Park crossing at the Northern Bypass, behind Gulshan-e-Hadeed and Dream World Resort. It ultimately reaches a catchment of the Lyari River, crossing Arzi Brohi Goth. The Northern Bypass, was proposed in the Karachi Master Plan, 1975–1985 and commissioned in 2004.

The latest map on Google Earth is from 2016. It becomes quite evident that from the surface you see that the construction of the Northern Bypass obstructed the original path of the Lath River. This was followed by the decision to lease lands for residential schemes. There are hundreds of housing schemes on both sides of the bypass. A majority of them have the prefix of Gulshan, some the suffix of lake city and some with scheme numerics. It seems that nobody bothered to undertake topographic or hydraulic contour mapping before giving away permission for housing in this area. 


All these developments obstructed the original flow the Lath River, which now takes a straight route and inundates the Super Highway. A solution seems to be difficult, but it can still be done. In the Global North they have large storm drains to speedily evacuation flood water. The Lath dam scenario needs a proper on-ground survey. The old route of the hill torrent can still be connected to Lyari. We may need to plan and design a large storm water drain on the original river course, with protective dykes. This will not only protect the residents of the Northern Bypass, but will also protect commuters on the Super Highway as well as Saadi Town. The crux of the problem is that when we go about expanding our cities and developing infrastructure, we should make them human friendly as well as disaster resilient.

Follow SAMAA English on FacebookTwitter, and Instagram.

 
 
HOME  
 
RELATED STORIES
 

12 Comments

  1. Avatar
    Bilal W.   August 11, 2019 11:24 pm/ Reply

    Excellent Analysis. Down right to the core of the problem.

    Let’s see if anyone really does something to address it’s blockage.

  2. Avatar
    Babar Chohan   August 12, 2019 1:11 am/ Reply

    Very good work on this issue,I really appreciate and hopeful if they will consider it as well for the people who live in the area.

  3. Avatar
    Adnan   August 12, 2019 1:13 am/ Reply

    Wow I can say that what a report by samaa. It’s provides the solution to save the Saadi town and also who cut the natural route of Lath damn to flow down.

  4. Avatar
    Abdul Salam Dadabhoy   August 12, 2019 2:31 am/ Reply

    Excellent analysis. Since I am familiar with the area this is one of the best solution I have read so far. Thank You.

  5. Avatar
    Haider   August 12, 2019 4:21 am/ Reply

    Well done! For the first time someone has pinpointed the actual cause of the inundation of Saadi Town every monsoon and a feasible solution! I pray that relevant authorities take action to construct proposed structures to allow natural drainage of water during rains and flooding.

  6. Avatar
    Salar   August 12, 2019 6:12 am/ Reply

    I request you to submit your analysis at E-portal.. Gov will def look into the matter and Do a favour to karachites

  7. Avatar
    sameer   August 12, 2019 10:02 am/ Reply

    The people in the area are suffering,this is carelessness by government, blocking water route by constructing northern bypass. Hope they would construct culverts in order to restore the natural water route.

  8. Avatar
    Sajid Usmani   August 12, 2019 12:43 pm/ Reply

    This is common mistake in the whole city. The lust of land has been the only reason. The whole city was blessed with the natural drainage and there was no Chowk point in the way of flash floods but since we started housing schemes towers and enchrochments without planning it resulted into kiosk. Besides this no one in the city have time to think about it. Shame for us.

  9. Avatar
    Abdul Jabbar   August 12, 2019 4:23 pm/ Reply

    Nature has made the courses of water , the rain water is always runs through its path that nature had made. It is human error that we deny this truth. And because of lack of rains we used the path as our living sites. Another disaster can be occur at Khuda ki Basti,North of Karachi because it is also built in the way of rain water course.

  10. Avatar
    Nadeem   August 12, 2019 6:41 pm/ Reply

    But , I still say that while making M9, this issue should have been worked out.

  11. Avatar
    Atif Hafeez Siddiqui   August 12, 2019 10:04 pm/ Reply

    Eye opener, good interrogation.
    Basically the result of land grabbing for money mounting.
    Currently, I don’t think any department can execute anything for betterment

  12. Avatar
    Adeel Z. Soomro   August 13, 2019 12:44 pm/ Reply

    I just read this article and thought, “OMG… SamaaTV? really????” Very pleasantly surprised by the quality and content of the article. Facts appear to be well researched and the science seems sound. I like the troubleshooting approach of laying out the symptoms of the problem, its root causes and some potential remedies

    I’d love to read more articles like this. They are dense with ideas and just the right length to be accessible. Kudos to the author (authors?), and to those who contributed their expertise.

    As for the problem described, it is certainly topical and needs to be addressed immediately. City government must take note!

Tell us what you think:

Your email address will not be published.

 

 
 
 
 
 
Islamabad, protests, police
 
MOST READ