A STUDY OF URBAN WATER DEMAND IN SOUTH KALIMANTAN PROVINCE

This research projected the citizens and water demand in 13 regencies/cities in South Kalimantan Province from 2013 to the next 20 years. The results of the project were compared with the intake capacity to meet the demand in upcoming years. In projecting the population growth, five methods were used, namely aritmethic method, geometric method, linier regression method, exponential method and logarithmic method. The most appropriate method for projecting the population growth is the method which has the minimum value of standard deviation and the correlation value close to 1. Water demand was calculated based on some factors, such as the average water demand, the maximum level of water demand, and the water demand at peak hours. The existing intake capacity was then compared with the water demand projection. In almost all PDAM (Munipical Tap Water Company) observed, the capacity of water processing installation could not fullfill the water demand at the peak hours. The adequate intake capacity of PDAM was only in Balangan regency and Banjarmasin city.


INTRODUCTION
Water resource plays an important role in supporting individual life, community, socioeconomic development of a region and environmental ecosystem.Various economic activities such as supplying raw water for household, agriculture, municipality, industry and energy always require not only the proper quantity and quality but aLo the reliable and sustainable service.The management of water resource manufacturing faces several complex issues in line with the population growth and the social and economic growth.In one part, the population growth increases the water demand for various purposes; on the other hand it leads to exploitation of water resources and its supports.The increasing water demand is in line with the population growth, social life standard improvement and economic development.Economic development in a region affects the population growth through the increase in vertility, chance of survival and mobility.
The high rate of economic development will be followed by the increase in urban water demand.Hence, the study of urban water demand in thirteen (13) regencies and cities in South Kalimantan province in the near future needs to be carried out.
The purposes of this study were to find out the percentage of the existing population growth based on the data of population for 5 years in order to predict the number of citizens for the next 5, 10, 15 and 20 years, to calculate the recent water demand until the next 20 years with an interval of 5 years, and to compare the intake capacity with the amount of water consumption in PDAM until the next 20 years.

METHODS
The percentage of population growth is needed to determine the average rate of population growth each year.The percentage of population growth can be calculated using the formula: -Explanation: r = percentage of population growth P 1 = number of first-year population (known) P 2 = number of last-year population (known) The projection of population in the future is very important in calculating the amount of drinking water demand in the future.This projection is based on the rate of urban development trend, direction of land use and availability of land to accommodate population growth.
Regarding to the rate of population growth in the past, statistical method is the most approriate method to estimate the number of citizens in the future.There are several methods that can be used to analyze the population growth in the future, namely arithmetic, geometric, linear regression, exponential and logarithmic methods.
To establish which method to be used, the determination of the lowest correlation value (r 2 ) and standard deviation (STD) are needed.

RESULTS AND DISCUSSION
According to Wikipedia Indonesia and the data from BPS South Kalimantan Province about the calculation data of population in 13 regencies / cities, the following are the results of the projection of population in South Kalimantan Province every five years.Based on the data in Tables 8 and 9, almost in all PDAM, the water processing installations could not meet the water demand at peak hours.Only Balangan regency and Banjarmasin city could afford it.Thus, the local government has to make new plans to increase the water processing installation (IPA) capacity and the machines in intake.Moreover, they have to think about new location of intake.
From the percentage in 2033, the regency or city which experiences the smallest population increase is Tabalong regency and Water Demand at Peak Hours L/sec the highest Hulu Sungai Tengah regency.However, the lowest increase in water demand at peak hours is in Banjarmasin city and the highest is in Banjarbaru city.This is understandable because the province capital has been moved from Banjarmasin to Banjarbaru since 2012.

CONCLUSIONS
From the results of data analysis in this research, it can be concluded that the lowest number of population is in Balangan regency (177,924 persons) and the highest is in Banjarmasin city (775,030 persons).However, the area with the lowest rate of population growth is Tabalong regency and the highest is Hulu Sungai Tengah regency.The lowest rate of water demand at peak hours is in Balangan regeny by 421 L/sec and the highest in Banjarmasin city by 2437 L/sec with the average number of population in South Kalimantan Province by 1,078 L/sec.However, the lowest rate of water demand at peak hours is in Banjarmasin and the highest in Banjarbaru.Almost in all PDAM, the capacity of water processing installation cannot meet water demand at peak hours.Only Balangan regency and Banjarmasin city have sufficient intake capacity.
There are some recommendations for providing clean water in Banjarmasin city.First, PDAM Banjarmasin must surpress the water loss until less than 20% in order to optimalize water distribution to citizens.Second, it needs to maintain the quality and sustainability of the environment near water sources and to prevent deforestation and river pollution.Next, it should maintain the efforts to optimalize the fulfillment of clean water demand such as by increasing both the existing capacity and intake production by adding the water extraction pump and increasing the volume of water processing shelter; increasing the number of intake points in rivers that have the potential for water resources for PDAM; optimalizing the water pump performance by replacing old pumps to maintain the stability of distributed water discharge; establishing a construction plan of artificial basin as the back-up water supply in case the existing water capacity is insufficient to meet water demand continually.

Figure 2 .
Figure 2. Domestic water demand in regencies/cities in South Kalimantan Province In 2033, the lowest domestic water demand is in Balangan regency by 204 L/sec and the highest is in Banjarmasin city by 1274

Figure 3 .
Figure 3. Non domestic water demand in regencies/cities in South Kalimantan Province In 2033, the lowest non domestic water demand is in Balangan regency by 30 L/sec and the highest in Tanah Laut regency by 266

Figure 4 .
Figure 4. Water demand at peak hours in regencies/cities in South Kalimantan Province.In 2033, the lowest water demand at peak hours is in Balangan by 421 L/sec and the highest is in Banjarmasin by 2437 L/sec

Table 1 .
Non domestic water demand based on the planning criteria in DPU can bee seen in Table2to 4. These tables display a standard that can be used to calculate urban water demand if the detailed data about city and its facilities can be provided.

Table 1 .
Criteria of clean water planning Source: Directorate General of Cipta Karya, Departement of PublicWorks (1996)

Table 2 .
Non Domestic Urban Water Demand Type I, II, III, and IV Source: Directorate General of Cipta Karya, Departement of PublicWorks (1996)

Table 4 .
Non Domestic Urban Water Demand Other's Type Source: Directorate General of Cipta Karya, Departement of PublicWorks (1996)

Table 5 .
Population Projection in South Kalimantan Province Figure 1.Projection of population in regencies/cities in South Kalimantan Province In 2033, the lowest number of population is in Balangan regency with total 177,924 people and the highest number in Banjarmasin city by 775,030 people.The average number of population in South Kalimantan Province is 376,135 people.

Table 6 .
Domestic water demand in regencies/cities in South Kalimantan Province

Table 7 .
Non domestic water demand in regencies/cities in South Kalimantan Province

Table 8 .
Water demand at peak hours in regencies/cities in South Kalimantan Province

Table 9 .
Intake capacity and water processing installation (IPA) capacity in regencies/cities of South Kalimantan Province.