new pimbahal pond 1880 (oldfield) - homepage | escap. pb joshi... · 2017. 12. 11. · traditional...

Padma Sunder JoshiUN-Habitat, Nepal

1ps.joshi@unhabitat.org.np

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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The ponds, aquifer and the hities

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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

17ps.joshi@unhabitat.org.np

Traditional Ponds: their types and functions

18ps.joshi@unhabitat.org.np

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

19ps.joshi@unhabitat.org.np

Traditional Ponds: their types and functions

20ps.joshi@unhabitat.org.np

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

21ps.joshi@unhabitat.org.np

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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

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Ta Pukhu at Kumari Pati

Case of Saptapatal Pukhu

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▪ 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

35ps.joshi@unhabitat.org.np

▪ 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......

38ps.joshi@unhabitat.org.np

Thankyou