new pimbahal pond 1880 (oldfield) - homepage | escap. pb joshi... · 2017. 12. 11. · traditional...
TRANSCRIPT
Padma Sunder JoshiUN-Habitat, Nepal
TRADITIONAL WATER MANAGEMENT SYSTEM OF KATHMANDU VALLEY:
Challenges and Opportunities
PONDS
2
3
Pimbahal Pond 1880 (Oldfield)
4
The Context
Bhaktapur
Thimi
Lalitpur
Kathmandu
Kirtipur
Topographic profile of Newar towns
5
The Newar Town Planning Concept
Agricultural domain
Human domain
Natural domainNatural domain
▪ Hiti system evolved to nurture the development of the great cities of the valley
▪ Hiti, the water spouts at manmade depressions are normally discharging through stone spout
▪ Hiti system utilise ground water, rain water and surface water to serve continuous flow through out a year
▪ These systems date back to 1500 years or more
Introducing HitiSystem
▪ The system utilizes Ground water
Surface water
Rain water
▪ Its components are: Raajkulo, the canals
Pukhu: the ponds
Hiti: the spouts
Tun: the wells
Dhown: the drains
Introducing HitiSystem
AquiferWater canal
Hiti
Pond
Rajkulo
Introducing HitiSystem
▪ Kathmandu: the Budhanilkantha System
▪ Bhaktapur: the Bageswori System
▪ Lalitpur: the Tikabhairav System
The rajkulo at Chapagaun
RAJKULO
Naykhyo Aquifer
Naricha aquifer
Guita Aquifer
Alkwo Aquifer
KhwyebahiAquifer
DhobighatAquifer
After P. L. Joshi
The Hydro-geology
Stupa at Lagankhel
Alkwo hiti invert level
Lakhe Chowk
Thapa hiti invert
GWT at Lagankhel dugwell
Reduced level
GWT
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gl/+rf
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The ponds, aquifer and the hities
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+ k'v'
The ponds, aquifer and the hities
▪ Fluvio-lacustrine deposits of the Kathmandu Valley can be divided into eight strati-graphic units
The Hydro-geology
The Hydro-geology
16
Traditional Ponds: their types and functions
▪ Ponds upstream of the settlements
▪ Ponds in the settlements
▪ Ponds downstream of the settlements
Traditional Ponds: their types and functions
Ponds upstream of settlement
▪ Buffer reservoirs
that collect rain water and surface water
recharge the aquifers
subsides flood in the settlement during downpours
irrigate during dry season
▪ Rani Pokhari, Lainchaur ponds in Kathmandu
▪ Ponds of Lagankhel, Pulchowk, Jyawalkhel
▪ Siddhi Pukhu, Rani Pukhu, Bhaju Pukhu in Bhaktapur
Traditional Ponds: their types and functions
Ponds inside settlement Relatively smaller in size
Collects storm water
Recharges local aquifers
Provides cleaning and washing water
Duck farming and animal husbandry
▪ Pimbahal, Purna Chandi, Kapinchhen
▪ Pako Pukhu, Khecha Pukhu,
▪ Khancha pukhu, ByasiPukhu,
Traditional Ponds: their types and functions
Ponds downstream of settlement Primarily for controlling flood and
landslide in the downstream of settlements
Dirty as used water is collected
Most of them are near open defecation areas
Water available for cleaning, duck farming, buffalo raising, and irrigating downstream
▪ Chyasal Pukhu, Guita Pukhu, Ligan Pukhu
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M k'v'
gfu k'v'
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afns'df/L k'v'
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rkfM k'v'
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Traditional Ponds of Patan
23
Condition of ponds: example of Patan
Out of 39 traditional ponds in Patan
▪ 16 are still intact
▪ 9 ponds are encroached and reduced in size
▪ 14 are already encroached
Ta Pukhu at Kumari Pati
Case of Saptapatal Pukhu
27
▪ Typical pond recharge system
Desilting unit
Intake
Recharge well
Silt depositionGravel bed
Schematic Diagramme: Recharge Pond with Central Well
Taking up the challenge
Taking up the challenge
▪ Lalitpur City is renovating 3 ponds for the recharge system
▪ UN-HABITAT and partners are supporting the process
Taking up the challenge
▪ Similarly community recharge wells are constructed
▪ Typical well recharge system
Recharge well
Gravel packing
Inlet chamber
Connection pipe
Natural gravel formation
Gravel packing
Boulder packing
Sand packing
X-Section Recharge System: Inlet and Recharge Wells
Taking up the challenge
Taking up the challenge
Paved streets and courtyards are the catchment for
RWH to recharge the ground
Taking up the challenge
Paved streets and courtyards are the catchment for
RWH to recharge the ground
Taking up the challenge
Other initiatives
▪ Janankpurcommunities initiating reviving the ponds
▪ Pani Bhakari
▪ Recharging is possible both at household and community level
▪ With the depleting GWT people are more and more attracted to this alternatives
▪ Since this is a communal activity their involvement in installation and management is important
What are the lessons learned?
Few challenges
▪ How to manage these systems in changed context?
▪ How to mainstream the maintenance and improvement in municipal system?
▪ Can't we replicate this in other cities and towns?
▪ More R&D......
