Projection of Clean Water Needs for Bandarmasih City Water Utility (PDAM) in Banjarmasin City, in the Banjarmasin Tengah Sub-district, for the Year 2031

geographical

The geographical situation of Banjarmasin City, which partly supports the availability of clean water for the community, is crucial considering the primary needs of the people by utilizing natural resources that are expected to fulfil the community's demand for clean water. The need for clean water must be met for the entire population of Banjarmasin, including the Banjarmasin Tengah Sub-district, a district in Banjarmasin, South Kalimantan Province, with an area of 6.66 km2 and a population of 91,780 people. The research method for preparing this report includes field surveys, collecting primary and secondary data, and conducting population projection calculations. A literature review was conducted by gathering, reading, and studying relevant sources such as journals and books necessary to conduct this research. Based on the analysis and discussion results, it can be concluded that the projected loss of clean water in the year 2031, assuming a standard rate of 36 L/s, is significant. The projected demand for clean water in the service area of the Central Banjarmasin branch of the PDAM in the projection year 2031 is approximately 215 L/s Indonesia is a developing country that is not exempt from challenges, including providing clean water. The need for clean water is of utmost importance. Thus, the clean water sector receives top priority for addressing because it concerns many people's lives. The geographical situation of Banjarmasin City, which partly supports the availability of clean water for the community, is crucial considering the primary needs of the people by utilizing natural resources that are expected to fulfil the community's demand for clean water.
The need for clean water must be fulfilled for the entire community of Banjarmasin, including the Banjarmasin Tengah Sub-district, a district in Banjarmasin, South Kalimantan Province, with an area of 6.66 km2 and a population of 91,780 people. This location serves as the final study site for PDAM Bandarmasih in Banjarmasin City, precisely in the Banjarmasin Tengah Sub-district, to calculate the clean water needs in that district. Planning, design, and facilities for collection, transmission, and distribution are necessary for a proper clean water supply. With PDAM Bandarmasih in Banjarmasin City, it has become a company that manages and serves the clean water needs in Banjarmasin, including the Banjarmasin Tengah area, where my final research project is located. Through this final project study, the method used is based on the clean water requirements, involving data collection from PDAM Bandarmasih in Banjarmasin City and conducting direct interviews at the research location in the Banjarmasin Tengah Sub-district area. It's essential to know the current and future demand for clean water in the Banjarmasin Tengah Sub-district and assess how far the level of PDAM network service can be improved.

Type of Research
The method is a process carried out in the calculation process. The steps taken in this calculation are field surveys, collecting primary and secondary data, and calculation analysis. A literature review is conducted by gathering, reading, and studying relevant sources such as journals and books necessary to conduct this research. Field survey involves direct observations to determine the location or place of data collection, capturing documentary photos, and conducting interviews with relevant parties as additional data to complement this research.

Data Collection
The data for this research consists of gathering the necessary data for the calculations. The collected data includes: 1) Collection of primary data. Primary data is data obtained directly. The primary data obtained includes documentary photos, interviews, and observations. 2) Collection of secondary data. These data are obtained from the local government agencies in Banjarmasin City, which are necessary for the data calculation. The visited agency includes the office of PDAM Bandarmasih in Banjarmasin City. 3) Calculation of additional population for the past five (5) years. This calculation utilizes the primary and secondary data mentioned above.
If the additional population calculation is correct (Yes), it will proceed to the projection calculation of the population for the next 12 years using the chosen method. If it is still incorrect (No), then the primary and secondary data mentioned above will be reexamined. 4) Projection calculation of the population for the next 12 years using the Geometric Method, as this method has the smallest Standard Deviation (SD) and the Correlation Coefficient (1) that closely approaches 1. 5) Projection calculation of clean water demand for the next 12 years. This projection calculation utilizes the chosen method, which is the Arithmetic method, by using the population figures from the years 2019, 2020, 2021, 2022, 2023, 2024, 2025, 2026, 2027, 2028, 2029, 2030, and 2031. The projected water demand includes Domestic Water Demand, Non-Domestic Water Demand, and Water Loss. 6) Total water demand. To determine the total water demand from the above calculations for the next 12 years up to 2031. The magnitude of this water demand is based on the projected planning calculations. 7) Conclusion. Based on the calculated results and discussions that have been projected.

Projection of Population Growth Rate
For estimating the future population in Banjarmasin Tengah Subdistrict, three methods are used: Arithmetic, Geometric, and Least Square.

Figure 1. Combined Population Projection Diagram
With the values of (r) and standard deviation (Sd) from the three methods above, the choice among the three methods can be determined to calculate the population projection for the next ten years. The selection of the projection method is based on the coefficient of correlation (r), which should be close to 1, and the standard deviation should be the smallest. The result of the correlation comparison of the selected method is with the Arithmetic method, as seen in Table 1, comparison of Correlation Coefficients and Standard Deviations.

Projection of Water Demand
The magnitude of water demand is influenced by several factors, which include Domestic Water Demand (consisting of Direct Connections and Public Hydrants), Non-Domestic Water Demand (including Education facilities, Commercial Facilities, Healthcare facilities, Religious facilities, Office facilities, and Industrial facilities), and Non-Revenue Water (Unaccounted for Water Usage).

Domestic Needs
The magnitude of clean water demand for domestic purposes is primarily determined by the population to be served, the type of connections, and the level of service provided. Clean water demand for facilities is divided into direct connections and public hydrants.

Non-Domestic Water Needs
Non-Domestic needs refer to water usage for purposes other than household consumption.
The amount of water needed to support educational facilities is determined by the number of students and the size of the facility, as shown in Table 3-projections of Clean Water Needs for Educational Facilities.

Table 3. Projected Clean Water Requirements for Educational Facilities
The amount of clean water demand for religious facilities is based on assumptions, as seen in Table 4, projected Clean Water Requirements for Religious Facilities.

Table 4. Projected Clean Water Requirements for Religious Facilities
Based on assumption calculations, the amount of clean water requirement for healthcare facilities can be seen in Table 5, projected Clean Water Requirements for Healthcare Facilities. Based on assumption calculations, the magnitude of clean water demand for commercial facilities can be seen in Table 7, projection of Clean Water Demand for Commercial Facilities.

Loss of Water
Water loss is the difference between the amount of water supplied and consumed. Water loss in a water distribution system is always present. This loss can be technical, such as losses due to the pipes themselves, while non-technical losses include water theft within the distribution pipes. We must consider the magnitude of water loss in the system to determine the extent of water demand. Water loss is estimated to be around 20% of the total demand until the end of the planning year (Public Works Agency, 2004). The amount of water loss in 2031 is projected to be 36 L/s, as shown in Table 8-Water Loss.

Total Clean Water Demand
The conclusion from the above calculations for the total water demand over the next ten years in 2031, the obtained production rate is 215 L/s. The magnitude of water demand is based on the calculations in Table 9, Total Clean Water Demand. Table 9. Total Clean Water Demand The projected demand for clean water in the service area of the PDAM branch in Banjarmasin Tengah in the year 2031 based on this prediction is approximately 215 L/dtk (litres per capita per day), where this flow rate is below the available production capacity of PDAM Bandarmasih, which is around 250 L/dtk (Uprating IPA II Pramuka for the service area of Banjarmasin Tengah). Therefore, for the year 2031, the capacity of the PDAM Bandarmasih's water treatment plant still meets or exceeds this prediction.

CONCLUSION
Based on the analysis and discussions that have been projected, it can be concluded that the estimated loss of clean water in the year 2031 with the assumed standard is around 36 L/dtk (litres per capita per day). The projected demand for clean water in the service area of the PDAM branch in Banjarmasin Tengah in the year 2031 based on this prediction is approximately 215 L/dtk, where this flow rate is below the available production capacity of PDAM Bandarmasih, which is around 250 L/dtk. Therefore, for the year 2031, the capacity of the PDAM Bandarmasih's water treatment plant still meets or exceeds this prediction.