This document discusses watershed planning and delineation of regions in India. It defines a watershed as the area of land where rainfall drains into a common body of water. Watersheds are hierarchical, with smaller watersheds draining into larger watersheds. The document outlines India's system for classifying watersheds from the largest water resource regions down to micro-watersheds of 500-1,500 hectares. It discusses the importance of watershed management and planning, which involves stakeholders across political boundaries. The functions and significance of watershed planning in regional development are also examined.

1. Regional & Metropolitan Planning
Dr. Mohammed Firoz . C
Architect and Urbanist
Department of Architecture and Planning
National Institute of Technology Calicut, India
Lecture 4

2. Water shed Planning and Regions of India

3. • A watershed is the total
land and water area, from
where the rainfall runoff
drains into any water body,
be it a stream, river, lake or
ocean. It may be a nearly
flat area or include hills or
mountains.
• It is considered to be
synonymous with a
drainage basin and
catchment area.
Watersheds are separated
from each other and the
boundaries are known as
watershed boundaries
Concept of Water shed
Watershed size varies as per the topography of
the land. Smaller watersheds drain into streams
and just as several streams form a river, several
small watersheds group to form a larger
watersheds or river basins with their own
defined ridgeline.

4. • Contt…..
• For an irrigation-cum-hydel project, the size for consideration may be several
thousands of square kilometers but for a farm pond it could be just a few
hectares. ( River basin to micro or mini watershed)
• Every land area is a part of some watershed. A watershed can be identified by
exploring the water body to which the water from our area drains to.
Functions :
• The main function of a watershed is to receive the incoming precipitation and
then dispose it off. It’s five major functions come under the following two
heads
• Hydrological functions
o Collect rainfall water
o Store water in various amounts and for different periods
o Release water as runoff
• Ecological Functions
o Provide conditions and sites for various bio-chemical reactions to take place
o Provide habitat for flora and fauna of various kinds
Functions of a watershed

5. Watershed Visualizations
1 2

6. • Water shed management : Watershed management is a term used to describe
the process of implementing land use practices and water management
practices to protect and improve the quality of the water and other natural
resources within a watershed by managing the use of those land and water
resources in a comprehensive manner
• Watershed Planning : Watershed management planning is a process that
results in a plan on how to best protect and improve the water quality and
other natural resources in a watershed.
• Watershed boundaries extend over political boundaries into adjacent
municipalities and/or states. Hence, a comprehensive planning process that
involves all affected municipalities located in the watershed is essential to
successful watershed management
Watershed Planning and Its significance

7. Importance watershed management:
• Runoff from rainwater or snowmelt can contribute significant amounts of
pollution into the lake or river. Proper Watershed management can therefore
help to control pollution of the water and other natural resources.
• All activities that occur within a watershed will somehow affect that
watershed’s natural resources and water quality. Hence, proper watershed
planning in accordance with the change in land use, development etc can
greatly help in sustainable development.
• Watershed boundaries do not coincide with the political boundaries, all
decisions taken with respect to such boundaries can affect the ecosystem.
Therefore, watershed planning is important
Watershed Planning and Its significance

8. Data Required for Watershed Planning
A comprehensive watershed planning require a lot of data, its interpretations
and analysis- An emerging concept in regional development and planning

9. Steps in watershed management
Step 1 : Identify the characteristics of the watershed and inventory the
watershed’s natural resources
oDelineate and map the watershed’s boundaries and the smaller drainage
basins within the watershed;
oInventory and map the resources in the watershed;
oInventory and map the natural and manmade drainage systems in the
watershed;
oInventory and map land use and land cover;
oInventory and map soils;
oIdentify areas of erosion, including stream banks and construction sites;
oIdentify the quality of water resources in the watershed as a baseline; and
oInventory and map pollution sources, both point sources (such as industrial
discharge pipes) and nonpoint sources (such as municipal storm water
systems, failing septic systems, illicit discharges).
A good amount of the data may be already available via secondary sources- say,
CPCB, Water atlas of India and many more

10. Steps in watershed management
Step 2 : Build Local Partnerships: Watershed planning should also identify and
include the partners, or "stakeholders," in the watershed.( Residents, farm owners,
Government etc)
Step 3:Understanding the Social, Ecological and Economical problems within
the watershed- Existing situation analysis
Step 4: Determine Priorities for Action:
Eg:
oInfrastructure improvements
oReducing paved areas and other impervious cover
oIdentifying appropriate areas for open space acquisition, greenways planning,
and the establishment of vegetated buffers
oIdentifying resource and wildlife habitat restoration priorities
oIncreasing and promoting public access and greenways
oImproving waste management, pollution prevention, and recycling efforts at
municipal facilities and businesses within the watershed
Step 5: Conduct Educational Programs.- Out reach, Capacity building etc
Step 6 :Implementation and Follow-up

11. S. No. Category of
Hydrologic Units
Example of
Code
No
( May vary)
(ha) Average Size (ha)
1. Water Resource
Region
2 6 270,00,000-
1130,00,000
5,50,00,000
2. Basins A 35 30,00,000-
300,00,000
95,00,000
3. Catchments 1 112 10,00,000-
50,00,000
30,00,000
4. Subcatchments A 500 200,000-
10,00,000
7,00,000
5. Watersheds 2 3237 20,000-300,000 1,00,000
6. Subwatersheds a 12000
approx
5,000-9,000 7,000
7. Microwatersheds 2 400000 app
rox
500-1,500 1,000
Systems of Classification of Watersheds in India

12. Indian Sub Continent- existing and proposed international watershed code for the
Indian River basins.
Classification of Watersheds-Indian Sub continent

13. On the basis of drainage flowing
into ocean and other basins,
three water divisions are
proposed
A for all drainage flowing into the
Arabian sea, B for all drainage
flowing into the Bay of Bengal,
and X for other rivers draining
into other basins
Classification of Watersheds –Water divisions- India

14. On the basis of drainage flowing into
ocean from north India, and south India,
each water division has been divided
into water sub-divisions. The water sub-
division code has been used as 1 for
North India, and 2 for South India
(i) All Drainage flowing into Arabian Sea
from North India (A1)
(ii) (ii) All Drainage flowing into Arabian
Sea from South India (A2)
(iii) (iii) All Drainage flowing into Bay of
Bengal from North India (B1)
(iv)iv) All Drainage flowing into Bay of
Bengal from South India (B2)
(v) (v) Other River Draining into Other
Basin from North India (X1)
(vi)(vi) Other River Draining into Other
Basin from Indian Island (X2) (
Andman, Lakshwadweep etc)
Classification of Watersheds –Water divisions- India

15. Classification of Watersheds -Basins and Sub basins
The entire country have been divided into a total of 34 Basins more or less
coinciding with the basins as delineated in Watershed Atlas of India, 1990 by
AISLUS (1: 1 million scale) which has a total of 35 basins except Brahmputra
whein left and right bank has been altered.
Basins constitute individual big rivers like Krishna, Narmada, Chambal etc. or a
combination of smaller ones which are contiguous to each other merged
together
Total 72 sub-basin boundaries have been delineated as the partition of basin
boundary. Each basin has been divided into a number of sub basins, which
connect to main tributaries or individual streams
Link to the Water shed atlas of
India

16. Classification of Watersheds -Basins and Sub basins

17. Classification of Watersheds -Watershed
Each sub-basin is
further divided into
watersheds, in
which sub-tributaries
and streams are
taken up for
delineation of
watersheds.
Example from
‘Dhasan’ Sub
basin

18. Classification of Watersheds -Sub Watershed
Sub water Shed : watershed has been divided into sub-watershed based on
main tributaries and streams extracted from Cartosat/ASTER (DEM).
Comprehensive code for a subwatershed is “AS06B1Gn(DSN)11k” as example
of a sub-watershed of Dhasan sub-basin
Micro Watershed- Sub watershed is further divided into micro watershed Micro-
watershed which can be defined as natural hydrological element that covers a
particular extent of terrestrial surface from which the precipitation, and runoff
flows into a well-defined river, stream, drainage, or channel at any specific point.
Mini watershed: The next order of hydrological unit is the Mini watershed. A
Mini-watershed (Mini-WS) boundary has been demarcated on each of 2nd order
stream

19. Classification of Watersheds -Sub Watershed

20. Classification of Watersheds -Sub Watershed
For more
details, refer
the digital
watershed atlas
of India

21. Water shed planning-Signiifcance in Regional Planning ?
Can a Water shed ( Sub, Micro, Mini Water shed ) or even a basin, Sub
basin be considered as a region ?
What is the Significance of Watershed in regional Planning ?
Does Delineating a region based on watershed boundary ( Ecological
boundary ) has Administrative and Implementation difficulties ?
Can better land use planning be done with Watershed boundaries ?
What are the potentials for such an evolving concept ?

22. Lecture 5 : Delineation of regions

23. Source of data for the lecture
https://www.indiawaterportal.org/questions/
frequently-asked-questions-faqs-
watershed#:~:text=In%20India%2C%20a%
20national%20level,sub%2Dcatchments%
20and%203237%20watersheds.
https://www.indiawaterportal.org/sites/india
waterportal.org/files/river-basin-
atlas_india_cwc-isro_2012.pdf
http://cgwb.gov.in/watershed/about-ws.html
http://slusi.dacnet.nic.in/dwainew.html
https://www.researchgate.net/publication/2
71520230_New_Watershed_Codification_
System_for_Indian_River_Basins
https://portal.ct.gov/DEEP/Wat
er/Watershed-
Management/Watershed-
Management---Overview
http://ecoursesonline.iasri.res.in/mod/page/
view.php?id=411