4.10.2.3 CONSTRAINTS AND POTENTIALS
Some of the characteristics of the existing scenario (both natural as well as man - made) within the city pose certain constraints, yet, offers certain potentials that need to be looked into and addressed for the betterment of the existing levels of service. Some of those could be outlined as under:
Constraints
• The current network (The central does not cover the entire area of
the current city limits).
• The existing settlements in the outlying areas are scattered in small
numbers all over the city. So, in most cases, new networks covering the whole
of the Urban Village area would have to be planned.
• Most of the outlying areas are covered by Rural Water Supply Schemes,
which do not have even the basic water treatment mechanisms ingrained in them,
as a part of the network.
• The quality of water supplied throughout the city is not uniform due
to the inherent differences in the kinds of network in use, in the different
parts of the city. Hence, the establishment of a uniform, basic treatment
mechanism would have to be devised for all the new source locations being
tapped.
• In the absence of any system of metering the local consumption in
certain areas of the city, billing for the services being provided poses difficulties.
• Not all areas covered within the current system, are provided with
a continuous supply of water. Most areas have an intermittent supply, which
raises concerns about possible deterioration in quality of the water being
supplied.
• Strengthening the existing networks in the outlying areas might prove
to be difficult in some cases, owing to the lack of sufficient capacity in
the existing infrastructure to be upgraded to a network covering the whole
of the Urban Village area.
• So, the integration of the scattered networks into new planned ones
might mean, discarding a few networks to be replaced by new ones.
Potentials
• There is availability of natural streams and springs along the whole
length of the city, which could be utilized as sources of water to meet future
requirements.
• This could permit the establishment of a decentralized system of water
supply, which would facilitate the tapping of the local sources and in the
process, allow the establishment of Local Area Networks.
• There are certain existing and operational minor networks, which could
be integrated into the new networks and operationalized wherever feasible.
• These detached networks could be controlled at the level of each Urban
Village, to have different and varying supply patterns as per the characteristics
of each Village and, device possible differential pricing patterns for different
segments as per the infrastructure and establishment costs of each area.
• Most of the existing settlements within the current city boundary
have been done in relation to, and in the proximity of, certain existing water
sources.
• A new planned network utilizing the local sources in the vicinity
of each of the Urban Villages would prove more cost effective in the long
run considering future anticipated growth scenarios, rather than a centralized
network covering the whole city.
4.10.2.4 MAIN OBJECTIVES OF THE PLAN
• To ensure an efficient and regular supply of potable treated water
for all the areas within the city limits.
• To ensure adequate tapping of available water sources and after treatment,
utilize them, as a part of the city water supply network.
• To enable a decentralized network of sources and supply networks to
reduce and distribute the anticipated load on the central network, in the
future, onto other subsidiary ones.
• To establish a cost efficient network, this would make use of the
gravity flow mechanism as much as possible, thus effectively utilizing the
local terrain characteristics. In a way reducing the need for expensive pumping
facilities to the bare minimum.
4.10.2.5 PROPOSED STRATEGIES
Distribution of Thimphu City into Zones According to its Topographical Characteristics
The physical formation of the Thimphu valley allows the sub - division of the entire physical stretch of the Thimphu city into a set of corridor formations, because of the unique pattern of minor valleys and ridge formations.
Location of a few streams coming down the valleys to join the river, characterize and allow the division of the physical stretch of the city into a few zones.
For the purpose of facilitating an efficient Water Supply System, the whole city would have to be broken into a set of zones as per the main sources available for tapping within the city.
There are on the whole seven sources that can be tapped for the production of potable drinking water to meet the future demands of water within the city.
These sources could be outlined as follows:
1. Chhubar Chhu 2. Samteling Chhu or Silikha Chhu
3. Simtokha Chhu or the Ola Rong Chhu 4. Serbithang Chhu or Ngabe Rong Chhu
5. Wang Chhu 6. Dechencholing Stream
7. Taba – Menchuna Chhu
The afore mentioned sources would be ideal for being tapped as potential sources considering the Safe yield capacities of each, and their proximity to designated future growth areas.
The need to allocate sources to all the city areas and the assessment of local topographical conditions, enable the division of the physical stretch of the city into five distinct zones, each of which would have distinct characteristics of source and supply.
Table 4.13: Outline Water Supply Zones and Designated Sources
|
Zone No |
Name
of the Zone |
Name
of the outlined source(s). |
| 1 |
Simtokha
and Babesa zone |
Simtokha
and Serbithang streams the Ola
rang Chhu and Ngabe
Rong Chhu. |
| 2 |
Lungtenphu
zone (Lungtenphu and Chang Jiji) |
Ola
Rong Chhu |
| 3 |
Central
zone (Core area, Langjophaka, Dzong area, National
Assembly area, Hejo, Samteling,
Motithang, Changzamtog,
Chang Bangdu |
Samteling
Chhu or Silikha
Chhu, Chhubar Chhu |
| 4 |
Taba
zone |
Taba
Menchuna Chhu |
| 5 |
Dechencholing
zone |
Dechencholing
stream |
Parameters for the delineation of the five zones
Zone - 1: The valley formations generated by the Simtokha and the Serbithang streams, physically separate the Simtokha and Babesa areas from the rest of the hill formations within the city. Hence, on account of the topographical characteristics of this area, these two Urban Village areas would have to be established as one zone for the provision of Water Supply, utilizing the bordering Simtokha Chhu or Ola Rong Chhu and the Serbithang stream or Nagbe Rong Chhu as sources.
Zone - 2: The Wang Chhu on the Western end and the Simtokha Chhu or Ola Rong Chhu on the Southern end isolate the Lungtenphu area from the other main areas of the city. Hence, this area comprising of the Lungtenphu settlement and Chang Jiji area could be grouped together as one zone with the development of the Simtokha Chhu, as the local source for this zone.
Zone - 3: The central portion of the city comprising of the Motithang area, the Core area of Thimphu, Changzamtog, Chang Bangdu, Yangchenphug, Zilukha, Hejo, Samteling and the Dzong area exhibit relatively better accessibility in terms of distance and terrain characteristics. Hence, these areas could be considered as a continuous stretch of development.
The availability of the Chhubar Chhu and Samteling Chhu or Silikha Chhu as two potential sources in this area, in addition to the above - mentioned criteria, makes possible the demarcation of these areas, under one zone.
The proximity and relative convenience in accessibility to Langjophaka (according to terrain characteristics and absence of any natural characteristics which inhibit the extension of the Central Zone Network to Langjophaka, and the absence of any significant source in the Langjophaka area,) from the Hejo and Dzong areas necessitate the inclusion of Langjophaka and the National Assembly areas into the Central Network. (The minor stream in the Langjophaka area could be developed as a back - up source).
Zone - 4: The Taba area would have to be designated as the fourth zone, both looking at difficult accessibility options posed by the local topographical characteristics and the existence of a potent local source to serve this area.
Zone - 5: The Dechencholing area lies isolated currently, because of the topographical characteristics of the valley and because of a narrow valley corridor, which physically connects it to Jongshina but does not contain any significant development.
Hence, the Dechencholing area would have to be demarcated as a separate zone using the local Dechencholing stream as the main source. The tapping of the Wang Chhu seems imminent in view of the anticipated future population in the Dechencholing area.
Besides this, the Wang Chhu would have to be tapped to include it as a part
of the Central Network, to meet future demands and also enable back - up supplies
to the Dechencholing and Taba local networks.