Detailed Project Report for Strengthening of the Di stribution etwork of Gangtok Water Supply Water Security & Public Health Engineering Department2-1 CHAPTER-2 POPULATION AND WATER DEMAND 2.1. PRESENT POPULAT ION The development of a particular city, town or a region depends upon natural, physical and socio-economic factors. Among these factors the population assumes significance in determining the future pattern of progress and development. Sikkim underwent many changes in its economy and demography after it joined the national mainstream. There was considerable increase in developmental activities, which caused a growth in urbanization. The population of Sikkim was slightly higher than 5, 40,000 in 2001 as against 4, 06,000 in 1991. Sex ratio of Sikkim was much lower (875 females) than the national average (933 females).Population changes from 1951 to 2001 show a growth of 3.9 times in Sikkim.Table 2.1: D emographi c Profile of Sikkim ` Census Year Total Population Rural Population Urban Population 1951 1,37,725 1,34,981 2,744 1961 1,62,189 1,55,341 6,848 1971 2,09,843 1,90,175 19,668 1981 3,16,385 2,64,301 51,084 1991 4,06,457 3,69,473 37,006 2001 5,40,851 4,80,981 59,870 Source: District Census Handbook 1951, 1961, 1971, 1981, 1991 and Primary Census Abstract 2001,Census of I ndia. Gangtok, the capital city of Sikkim is located in the East District and lies between 2 7° 21’ to 27° 16’ N latitude and 88° 37’ longitude with an altitude of 5500 ft above mean sea level. Gangtok is connected by National Highway (31-A) to Siliguri, which is a major town in the North of West Bengal. The nearest airport and railhead near Siliguri is 117 kms from Gangtok. The total area of Gangtok covered under this project is around 2112.11 hectare. This area falls under the following revenue blocks – Penlong, Burtuk, Sichey, Chandmari, Rongyek, Gangtok (includes Rajbhavan), Tathangchen, Tadong, Syari a nd Samdur. This report is prepared considering the population of Gangtok in 2001 as 82149. The ward wise a breakup of population of the project area is given in Table 2.2.This excludes the tourist population.
Detailed Project Report for Strengthening of the Distribution etwork of Gangtok Water Supply
Water Security & Public Health Engineering Department 2-1
CHAPTER-2
POPULATION AND WATER DEMAND
2.1. PRESENT POPULATION
The development of a particular city, town or a region depends upon natural, physical andsocio-economic factors. Among these factors the population assumes significance indetermining the future pattern of progress and development.
Sikkim underwent many changes in its economy and demography after it joined the nationalmainstream. There was considerable increase in developmental activities, which caused agrowth in urbanization. The population of Sikkim was slightly higher than 5, 40,000 in 2001as against 4, 06,000 in 1991. Sex ratio of Sikkim was much lower (875 females) than thenational average (933 females).Population changes from 1951 to 2001 show a growth of 3.9
times in Sikkim.
Table 2.1: Demographic Profile of Sikkim`
Census Year Total Population Rural Population Urban Population
1951 1,37,725 1,34,981 2,744
1961 1,62,189 1,55,341 6,848
1971 2,09,843 1,90,175 19,668
1981 3,16,385 2,64,301 51,084
1991 4,06,457 3,69,473 37,006
2001 5,40,851 4,80,981 59,870
Source: District Census Handbook 1951, 1961, 1971, 1981, 1991 and Primary Census Abstract 2001,Census of India.
Gangtok, the capital city of Sikkim is located in the East District and lies between 27° 21’ to27° 16’ N latitude and 88° 37’ longitude with an altitude of 5500 ft above mean sea level.Gangtok is connected by National Highway (31-A) to Siliguri, which is a major town in theNorth of West Bengal. The nearest airport and railhead near Siliguri is 117 kms fromGangtok.
The total area of Gangtok covered under this project is around 2112.11 hectare. This areafalls under the following revenue blocks – Penlong, Burtuk, Sichey, Chandmari, Rongyek,Gangtok (includes Rajbhavan), Tathangchen, Tadong, Syari and Samdur.
This report is prepared considering the population of Gangtok in 2001 as 82149. The wardwise a breakup of population of the project area is given in Table 2.2.This excludes thetourist population.
Detailed Project Report for Strengthening of the Distribution etwork of Gangtok Water Supply
Water Security & Public Health Engineering Department 2-6
Figure: 2.1 Population Projections by Graphical Method
The summary of the population forecast is tabulated in Table 2.4
Table 2.4: Population forecast for project area by various methods
Year
AirthematicProgressionMethod
IncrementalIncreaseMethod
GeometricIncreaseMethod
State UrbanAverageMethod
GraphicalMethod
2010 99092 104064 139060 133102 110000
2025 127330 151058 334353 218025 150000
2040 155567 211136 803911 302947 190000
It is evident from the table that the population forecast by Arithmetic Increase Method is
lowest. The Graphical Method is around average of all the four methods except GeometricalIncrease Method, while the higher values obtained from geometrical increase method maybe attributed to the job opportunities which Gangtok offers. Hence, for ward-wise populationprojections and design population Graphical method figures are used.
Detailed Project Report for Strengthening of the Distribution etwork of Gangtok Water Supply
Water Security & Public Health Engineering Department 2-9
2.4. WATER DEMAND
Water demand for Gangtok has been estimated based on the guidelines laid down in
Manual for Water Supply and Treatment published by Ministry of Urban Development, Govtof India.
The recommendations as per CPHEEO Table No. 2.1, which is reproduced as Table 2.7below:
Table 2.7: Recommendations as per CPHEEO
S.No. Classification of Towns/Cities Recommended Max.Water Supply (lpcd)
1Towns provided with piped water supply
but without sewerage system
70
2Cities provided with piped water supplywhere sewerage system isexisting/contemplated
135
3Metropolitan and mega cities providedwith piped water supply where seweragesystem is existing/contemplated
150
Note:
1. In Urban areas, where water is provided through public stand post, 40 lpcd should be considered.
2. Figures exclude unaccounted for water (UFW) which should be limited to15%.3. Figures include requirements of water for commercial, institutional and minor industries. However the bulk supply to such establishments should be assessed separately with proper justification.
Gangtok is the capital of the state of Sikkim and is the most important economic centre inthe state. It is provided with piped water supply where sewerage system is existing/contemplated. In view of the above, the per capita water supply for Gangtok has been takenas 135 lpcd + 15% Losses.
Table 2.8: Water Demand
Year Design Population Water Demand (135 lpcd + 15% losses) MLD
Detailed Project Report for Strengthening of the Distribution etwork of Gangtok Water Supply
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Table-2.9 Ward wise Water Demand
Wards Year 2010 Year 2025 Year 2040Total Water
Demand MLDTotal Water
Demand MLDTotal Water
Demand MLD
Penlong 2182 0.3 3082 0.5 4370 0.7
Burtuk 7213 1.1 10133 1.6 13933 2.2
Sichey 9999 1.6 14498 2.3 17760 2.8
Chandmari 4186 0.6 6070 0.9 7436 1.2
Rongyek 1515 0.2 2083 0.3 2552 0.4
Tathangchen 3554 0.6 5107 0.8 7283 1.1
Tadong 26656 4.1 38802 6.0 54020 8.4
Syari 5206 0.8 7939 1.2 10701 1.7
Samdur 6226 1.0 8082 1.3 9900 1.5
Gangtok 53263 8.3 74203 11.5 92046 14.3
Total 120000 18.6 170000 26.4 220000 34.2
It has been generally observed in the hilly areas that most of the growth is along the mainroads of the city. First, the areas along the main road are occupied and gradually population
pockets start occupying the areas off the road. It has also been found that huge patches of land remain unoccupied just because they are far from the road. Hence, for design purposespopulation catered to per meter of pipe laid for each ward is used for pipe sizing etc.
