#Thread

What geographical features can we observe from the sky while on a flight from Thiruvananthapuram to Chennai? (approx path in map) Equip yourselves with apps for more information from GPS.. Also notice the weaker signals from the satellites on the right side because I am sitting on the left side windows. Also preload maps in google maps so that you can identify features

#Thread on #Tiruchendur erosion

Of recently, we might have come across the news that a lot of erosion has happened right next to the famous Murugan temple in Tiruchendur. In this thread of maps, I would discuss the causes and possible solutions
To provide context, this photo shows the area near the next to the temple which has eroded significantly and the beach used to extend further

#Thread without Maps on #floods
If physical problems and solutions are known theoretically, then why are we not able to solve flooding situations in our cities whether it is Chennai or Bengaluru or Delhi?

There are 4 layers to the prob - Technical, Planning, Finance, Governance Technical:
Our cities are not designed to take the rainfall that they face. The storm water drains are inadequate and the network is disconnected. Most of the drains are built in adhoc manner (if they are built). But why does this happen?

#Thread on Vijaywada floods
In September this year, after a spell of heavy rain, Vijayawada was affected by severe floods. This thread would explore the geographical reasons behind it and what can be done from here.
(1/n) 2. #Map shows the profile of four major rivers in India. Vijayawada is in the lower section of Krishna river and close to where the river exits the plateau and enters the deltaic flat plains.

Google maps shows my GPS position to be well inside the sea in #Chennai Marina beach. But I was away from it. Why?

#Thread continuation of my previous one on Chennai #Marina beach
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In the previous thread, I had explained how Marina beach is growing (sea becoming more and more land). Because of the longshore drift, lots of sand hence gets settled in the mouths of Cooum River.

#Thread
#Marina beach is one of the most iconic destinations in Chennai and one of the most visited beaches in the world. However the beach as we see today didn't exist a century ago.

This thread explains the formation of #Chennai's Marina beach
1/n This map below shows the approximate original coastline of Chennai during British era. It was much closer to the Kamarajar road. A promenade was developed during the british era and that is when it got the name, "Marina". However the big sandy expanse itself didnt exist
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#Thread of #Maps that can help understand the #WayanadLandslide incident, its causes & impact

Please note that all the maps below were created with the information available as of now. Some of the damages outside the areas denoted might have been missed as info keeps coming 1. This part of #Wayanad is within the Chaliyar river system. It is a west flowing river which drains into the laccadive sea on Kerala coast (though at this part it is north and east flowing)

This map shows where the water drains. The area that is affected is shown in red.

#Thread
A collection of geographical myths & unknown facts about #Kanyakumari

1. Kanniyakumari is NOT the southern most point of mainland India, the southern most point is near star of the sea rock in nearby #Kovalam. In the last 20 years,it has been popularized as sunset point 2. Contrary to popular opinion, the three seas (Arabic Sea, Bay of Bengal, Indian Ocean) don't meet in Kanniyakumari.

Officially, the sea around Kanniyakumari district is Laccadive sea. Check map below for official extents of the seas and their names

Here's a compilation of my #maps which can help you in understanding the #Bengaluru #Water situation a bit better.

Bengaluru is unofficially a hill station which is located nearly a kilometre above sea level. Being in the top of a ridge line, the city is partly within Kaveri watershed and partly in Ponnaiyar (Dakshina Pinakini watershed).
Being on top, water from elsewhere dont flow through Bengaluru but flow outward from the city

Here is the story of how @googlemaps helped me recover items stolen in a moving train from my father.

My father was travelling from Nagercoil to Trichy in sleper class in Nagercoil - Kacheguda express. He had boarded at 1:43 AM from NCJ. The train was relatively empty & another person who boarded along with my dad stole my dad's bag and mobile phone from him, and deboarded the train in Tirunelveli Junction. When my dad realized it, he searched in the train and rang me from his friend's phone at 3:51 AM to inform that his phone was stolen. Luckily, among immediate family members we have location sharing "on" which meant I could track the location of mobile. When I checked it, I realized that the mobile was moving along the track near Melapalayam in Tirunelveli so I deduced that the thief was returning back to Nagercoil in another train.

Thread:
I'll summarise the #Chennai cyclone event and the flooding issue once again as I feel that there is a lot of misinformation floating around which could guide people and government in wrong way w.r.t future actions
#ChennaiFloods2023
1/n 1. The cyclone path had been more or less accurately predicted by IMD, private forecasters

2. The intensity of rainfall however was not clear as per official forecast though it was expected to be heavy, it was not indicated that it would be near record rainfall

Short thread:
#Chennai, lakes, and floods

I have written some threads about the flooding in Chennai, this one would focus specifically on the lake aspect.

#Map below shows the flood forecasted areas in Chennai for an extreme amount of rainfall. If we carefully look into this forecast map, we can see that apart from the major rivers, there are many other paths for the water to run which appear like a tree branching out.

This forecast based on coarser DEM with extreme rainfall & was prepared by my team mates @smkirthiga & pavithra

Pardon the visual quality of maps since I dont have much time to prepare this
If we look at the topography map, the flow paths become clearer as in the map below. When water falls in these places, they are supposed to drain along these streams which appear only during monsoons

Thread:
A recent #satellite image of the sea near #Chennai's Marina beach. There are 3 dots in the image (red, green, blue). What causes it? Satellites have cameras that observe reflection in different spectral bands (including red, green, blue). But they don't observe the same place at the same time and there is a very small lag between them. Meaning between red colour and green colour there is a time difference

#Thread: A Problem in the making. Two major problems faced by #Bengaluru are flooding and traiffic. But just like any other Indian city, unbridled urbanization is aggravating these crises and is making sure that these problems would stay for longer
1/n In my previous posts, I have explained about the topography and valley system in #Bengaluru. These conveyor belts carry the flood waters of the city. It is across these valleys small dams were built primarily for irrigation purpose (which we now call as lakes)
2/n

#Thread on Ponniyin Selvan #Maps
Last year, I had the opportunity to work as map consultant in director Maniratnam's magnum opus, #PonniyinSelvan movie. Though seen only in bg, there was a lot of professional effort put into maps which must be the 1st in Indian film industry 1/n Maps show the core Chola territory and the areas that were conquered and subdued.

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Short #Thread: Does the #Cauvery river need another dam?

Kaveri river is one of the most exploited watersheds in the world and yet there are many calls from both Tamil Nadu and Karnataka public to build one more mega dam
1/n It raises from a myth that there are not enough dams/regulators in Kaveri.
But there are more than 28,000 artificial constructions across Kaveri & its tributaries as Dams,Weirs,Regulators so that water could be stored/diverted for consumption- Agri, Energy, drinking
2/n

#Thread

Another city, another neighbourhood, another stream but same story

This is about a nala that flows through the dense urban concrete jungle of #Hyderabad city. It flows through Padma colony of nallakunta neighbourhood and eventually joined Musi river. Like many streams and canals in urban environment in India, this stream also didnt have any buffer in case of severe floods and jailed with concrete walls and no room for it to breathe. For most of the year, these streams carry sewage water.

#Thread on Local Football

WorldCup is over. Though football has lost media attention in India,local football is living& thriving even under difficult situations

As my club is gearing up to organize a tourney, I'm writing this to show d love & troubles, d game faces
@Udhaystalin Contrary to perceptions & opinions, Football is quite popular in many places in India like my town (Nagercoil, Tamil Nadu). 300-500 people (mostly young) attend matches even when conducted during the peak of summer and during a working day. Photo taken during pre-match
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I am yet to write all my suggestions related to the climate action plan for Chennai which has been open for suggestions

But wanted to say this:
Please DON'T take all these sea level rise maps from the report that depends on climate central. These are INCORRECT.
@chennaicorp What is wrong:
1. Elevation models used for these analyses are incorrect
2. climate changed induced sea level rise wouldn't act like a bath tub where water rises just like that
3. There would be formation of new beaches and erosion and would be different from current topography

#Bihar
1) Throughout the entire south west monsoon season, Bihar and the catchments of the rivers that flow through it have been facing deficit rainfall. But.. 2) Throughout the entire season, Kosi river has been flowing above warning level for every day and above danger level almost every day!

Isnt it odd that a river basin that is facing deficit and drought like situation have flood too simultaneously?

Short Story: 🧵

Near wonderla exit in #Bengaluru - Mysuru road, there existed a valley system (flow directions indicated below). Few irrigation tanks were also there in the valley (marked in blue).

1/n The construction spree on top of the valley system started when the road was expanded along with a toll gate right on top of valley! And other builtup came along the highway too completely causing the valley system to be obstructed.

2/n