4.10 UTILITY SYSTEMS

4.10.1 INTRODUCTION

This section on the Proposed Utilities and Infrastructure takes into account the projects and proposals envisaged by various Government Departments in addition to the proposals by DUDES and TCC. The proposals are related to the Population Accommodation Capacity of the city and proposed Urban Villages.

The section starts with Public Health Engineering Facilities (Water Supply and Sewerage Networks) It depicts the existing scenario as regards these aspects and states proposals for future. It is followed by study and proposals for Solid Waste Management System that emphasizes on segregation and decentralization of collection and disposal mechanism. The Power Supply Network study, documents the power cable network, substation locations, transformers, distribution pillars and mini - pillars as well as overhead high tension lines. It incorporates the future proposals of Department of Power. Finally, the study of communications networks, documents underground cable lines, transmission relay stations, and the cable TV line network and includes the projects of Bhutan Telecom Corporation.

4.10.2 WATER SUPPLY

4.10.2.1 EXISTING SITUATION

City Structure and Population Characteristics

The Thimphu city accommodates a population of 43,479 1.. This population is spread out over an area of approximately 26 sq km. The city at present could be characterized as an agglomeration of isolated pockets of settlement, each with varying population and density patterns.

The main intensity of development is currently concentrated in and around the Core Area of Thimphu (Wards 3 and 4). It is these areas that account for about 30% of the whole population followed by the areas adjacent to the Core, which take up another 36% of the total current population within the city limits2..

The Water Supply system currently operational within the City

Owing to the scattered pattern of settlement, the system of Water Supply within the current city limits, functions technically under the following two main categories:

The Existing Central Network and Rural Water Supply schemes

The current network, which has been termed as a central network, serves the Core area and certain adjoining areas of the Core area of Thimphu (Ward: 4). (Mainly, the western parts of the upper city areas.)

The existing central network comprises of four raw water streams, two treatment plants, 10 water reservoirs, one standby tank and approximately 70 km of distribution pipeline.3 Of the two treatment plants i.e., the one located in the Upper Motithang area currently functions as the Main Treatment Plant, which produces 90% of the water supplied through the Central network. The water for this treatment plant is tapped from three streams in the western part of the city. The current capacity of the treatment plant is 6500cum/d.4 The treatment process adopted in the Main Treatment Plant involves a conventional process combining flocculation, sedimentation, rapid sand filtration and chlorination. Alum is used as a coagulant.5

The second treatment plant currently functional in the vicinity of Jongshina has a designed capacity of 500cum/d and mainly serves the Dzong area and the crematorium complex. The method of treatment adopted in this case consists of sedimentation and rapid sand filtration. The water is tapped from the Samteling Chhu or Silikha Chhu, which as per rough flow measurements, is believed to have a safe yield of 10,000cum/d.6 The Samteling treatment plant is currently being up - graded to a capacity of 8500 cum/d to serve the Core area of Thimphu, the Dzong area, the National Assembly campus, and the Hejo, and Langjophaka areas.

The outlying areas within the current city limits, which are not serviced by the Central Network, are serviced by individual Rural Water Supply Schemes. These Rural Water Supply Schemes provide raw natural water tapped from the nearby streams without any treatment. The distribution network in most cases consists of privately owned plastic pipes and hoses attached to a main line laid out by the Public Health Engineering Division, of the Ministry of Health and Education. This network does not follow any hierarchical structure and primarily serves the purpose of providing water supply to the scattered settlements in the outlying areas.

1. As per the population surveys conducted by the Thimphu Municipal Corporation in 2000.
2. As per the assessment done by the analyst in each one of the Proposed Urban Village areas of the city, as a part of the Thimphu Structure Plan exercise.

3,4,5,6 Technical data abstracted from the THIMPHU WATER SUPPLY EXTENSIONS, Network Analysis by DANIDA, March-2000.

4.10.2.2 DEMAND

Consumption Patterns

As per the records maintained by the TMC, the current annual supply of water is close to 2.7 M cu m (Million cu m). This averages to a demand of about 7560cum/d (Cu m per day). Assessment of the water supply records supplied by TMC (Thimphu Municipal Corporation) for the months ranging from August 97 to July 98 indicate that the monthly per capita consumptions of water, range from 147 Liters/capita/day to about 175 Liters/capita/day which amounts to a per capita consumption of approximately 148 Liters/capita/day.

These figures account for the water consumption recorded on the Central Network only. There are no clear usable records on the water consumption patterns through the Rural Water Supply schemes in the outlying areas. Hence these figures might vary slightly if approximate estimates of the consumption in the outlying areas are considered for calculations.

The consumption patterns of Domestic and Non - domestic nature under the different component categories during 1998 - 1999, highlight the following facts:
• The consumption for Domestic use accounts for 71% of the total water consumption
• The consumption by Institutional campuses accounts for 24% of the total consumption
• The hotels account for nearly 3% of the total consumption
• The industrial areas account for about 2% of the total consumption

So, it would be safe to assume that the proportion of Domestic to Non - domestic consumption within the city varies as 70% - 30% respectively.

Demand forecast

The demand was calculated based on an assessment of the total population that could be accommodated in each one of the proposed Urban Village areas as per the appropriate density levels established for each area.

The existing population figures were derived through a detailed assessment of the total built structures existing under each one of the proposed Urban Village areas.

Their current floor heights were looked at to locate further densification possibilities, and to come to an assessment of the number of households approximately accommodated currently, in each. Based on these calculations, estimates of the existing population in each of the Urban Village areas were arrived at.

Firstly, the existing built structures that offered possibility of densification were identified, to arrive at a population figure that could be accommodated in the Urban Village area purely through vertical extensions of certain low height built structures.

Secondly, the areas currently having less than an optimal site coverage (in terms of the built - up area with respect to the site area) were identified as potential sites for horizontal densification or increasing the built density, and accordingly, the population accommodating capacities of these areas were arrived at.

Thirdly, those areas that were lying vacant and which did not fall under any restriction or Environment Conservation Precincts (E1), either according to environmental parameters or otherwise, were assessed for their population accommodating capacities, with different density thresholds assigned to each, as per their individual characteristics.

So, the population that can be accommodated in each Urban Village area was a figure, arrived at by combining results from all the above considerations.

As per the envisaged growth strategy (being formulated as a part of the Structure Plan), each of the Urban Village areas would be made up, of a Neighborhood Node, an Urban Village Core
(UV - 1), an Urban Village Periphery area (UV - 2) and other areas falling under the Urban Village Enclave (UV - 3), Agriculture Precinct (E - 3), Agri - based environmental precincts (E - 4) and other Precincts.

The consumption patterns of each of these sub - components of an Urban Village are expected to be different. But, for the purpose of arriving at standard parameters for calculating the demand in all the Urban Village areas, the earlier quoted Domestic to Non - domestic proportion of 70% - 30% respectively, has been considered, with an addition of 15% to the total demand (Domestic and Non - domestic) to account for possible network losses.

 

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