Know thy Hydro

Author Date Time to Read License
Cosmobird + Ganesh 26 Oct 2017 30 mins. cc-by-nc-sa

Hey there Water drinkers !

We all know Water is the elixir of Life. And freshwater is is much more scarce elixir of Life. When there is more living beings in a planet, competition emerges to sustain life that depends on this elixir. With humans in such an ecosystem, known for consuming water from cleaning our ass to making useless beverages - makes the competition much worse. Especially when the raging market for water packed in polyethylene bottles and selling sand that once was a river and lake beds to meet the accelerated urbanization requirements become normative. It turns out humans are their own problems. I mean me too.

Beautiful Meandering history of Mississipi River

Well i dont know what i can contribute to solve this problem, apart from being conscious and take part in protests as a usual common citizen would do. But i can do one more thing that feeds my intellectual capacity as well as letting myself understand the problem from a scientific but associated perspective. With that intention & existing know how of handling GIS data, tools, some theory & internet i think i can do something about it. But why River in particular ? I view common water bodies as (rivers, acquifiers, lakes, ponds, tanks) as the common representator of water collection, flow, banking, and contributor of complex ecosystems which in turn contribute to other ecosystems. Its flow completes the natural water/hydrological cycle.

Liking the power of Free Software tools contributed by awesome developers, students, researchers all over the world is just one thing. Doing stuff using it is completely a new experience. It is definetely a interesting and addictive task. It is like having a katana collaboratively made by swordsmiths trained by good martial art mentors. If i am not good making katana, i shall learn to use it. Since now i can access the information how it is made and why it is made so, it will help in slashing through realworld problems and issues. One has to know how to use it & when to use it.


Being conscious and aware about the problems surrounding us are vital, and getting to know about the geographical nature & environment that sustains us is much more essential. It is the material & immaterial fabric that connects us. Exploring the topography around ones location, aided with the modern FOSS tools, is not equivalent to what one shall enjoy in taking a magnetic compass, finely scaled map, trekking, taking notes, surveying, collecting data from nature, recording nature's awe but will surely reduce the labour that loads our intellectual work, so that we can use it wisely for craftsman ship embedded in the work. This is what i have tried to attempt in the earlier article, to start with.

Starting from the common GIS workflow again guides one to keep the process simple and explainable. In this attempt we are trying to look at the river of interest and see how come FOSS based tools, libraries, Open data, Open Access research papers, & internet will help us explore.

Common GIS Workflow

Learning hydrological view of nearby Water bodies (ex: River) has sure lead the exploration to all other overlapping transdisciplinary fields. It is a wonderful way of learning geo-sciences that also lets one constantly be aware about the socio-economic influence it always has in human history. So, before doing something with the tools that provides the power, one has to know the theoretical understanding of what hydrology mean, how it is related to fundamental topography and how will it water collection, flow, & storage, until it confluences to either the ocean or sinks to a land locked lake/pond.

Its wise to remember, that both terrain study and hydrological study of a region is carried out using calibrated survey instruments, trained workforce constituting managers, researchers, scientists, surveyors, auditing officials, etc. This attempt is to see how far we can go with Open data, FOSS tools & Open Access Research. Labour put into such tedious task of collecting data representing "ground truth" & disseminating data for further use must be thanked. It is a well known fact, that geospatial science has always respected, adapted and contributed for Open systems & standards.


Hydrology, as far as i understand constitutes knowing about several kind of data, and related knowledge about it. Only then one can understand how labouriously collected can be put together to make sense of it. Also from a community of individuals perspective, working on how to extract useful, intutively interpretative & interactive information about the local region is of fundamental importance. As the Region is now bounded it requires relatively very less computing requirements, and when exceeds a individuals power, communities support in handling the load & making the work very feasible and useful at the end.

Understanding Hydrology Workflow

Topography of a region decides the hydrological effects. Learning about one have lead to learning about the other. Understanding about the information dependence lets us see how terrain contribute to formation of catchment basins. With the availability of open data and internet, one can analyze and visualize topography from the Terrain data available in public domain. Furthermore, access to Spectral remote sensing data, and their derived indices (water, vegetation, turbidity, ...) help visualize how the flow of water & its storage form the hydrology throughout its presence. Then one could see clearly how the fundamental topographical & hydrological nature of a region influences the cultural & socio-economic conditions.

Knowing surface/terrain information and generating topographic details from it for the selected region, based on administrative boundary will be the most intuitive way to focus the scope of play and analysis. When the region of interest, cannot be confined within a specific administrative boundary, one may have to widen the scope of interest to more than one geographical regions, spanning neighbouring villages or districts or counties or states or countries. This makes the boundary information to be accurate and satisfactory for included administrative regions. Care needs to be taken that such an attempt must not trigger any boundary related issues while publishing.

But Why ? In the case of hydrological study, for instance a river, which naturally provides resources for more than an administrative region is an undeniable common and shared resource. In such cases starting from topographic analysis to extracting hydrological and socio-economic or cultural information needs to include plurality of inter-boundary features. Every step of the study & analysis must be underpinned with scientific and engineering principles & practices.

Since, i have already tried understanding terrain and extrating topographic information associated with it, in an earlier article, as in the above picture. It would be better to further see how it helps in associating with hydrological understanding. Also, since my interest is now aligned with studying and analysing hydrology of south indian river Palar. Thus now, the region of interest, must span the districts in each of the 3 states, through out which Palar flows:

  • Karnataka
  • Andhra Pradesh
  • TamilNadu


  1. 3 decades of Global Water Change - Derek Watkins & Henry Fountain
  2. SoLIM Project - Prof. A-Xing Zhu., University of Wisconsin, Madison
  3. Topographic partition of watersheds with Digital Elevation Models - Band L.E., 1986
  4. Extraction of Channel N/W's & Topographic parameters from Digital Elevation data - Band L.E., 1993
  5. River System Analysis & Management - Nayan Sharma
  6. International Freshwater Treaties Data - by River Basin
  7. 3D mathematical model to simulate groundwater flow in the lower Palar River basin - M.Senthilkumar., 2004
  8. High chromium tolerant bacterial strains from Palar River Basin: impact of tannery pollution - K.Sundar et. al., 2010
  9. Multivariate and geostatistical analysis of groundwater quality in Palar river basin - Sajil Kumar et. al., 2011
  10. Modeling pollutant migration in the upper Palar river basin, Tamil Nadu, India - M.Thangarajan., 1999
  11. Geochemical processes controlling the groundwater quality in lower Palar river basin, southern India - M.Senthilkumar & L.Elango., 2013
  12. Major ion chemistry and hydrochemical studies of groundwater of parts of Palar river basin, Tamil Nadu, India - M.A.Dar et. al., 2010

Tools & Models:

  1. uDig Spatial Toolbox for hydro-geomorphic analysis - Wuletawu Abera et al., 2014
  2. SHETRAN - Hydrological Model
  3. Groundwater Techniques, Methods, and Models - USGS, Water