Forecasting and Sustainability of Raw Water Supply for Indonesia’s New Capital

On Monday, August 26, 2019, the Indonesian government formally announced at a news conference held at the State Palace in Central Jakarta that the area would function as the country's new capital (IKN) [1]. The government decided to relocate the capital city from DKI Jakarta to parts of Penajam Paser Utara Regency and Kutai Kartanegara Regency by 2024 [2, 3]. According to data from the Central Bureau of Statistics for East Kalimantan Province for 2022, the population of Penajam Paser Utara Regency will reach 185,000 people in 2021 [4]. The Ministry of National Development Planning/National Development Planning Agency (PPN/ Bappenas) asserts that this plan will be implemented because it is included in the 2020-2024 national medium-term development plan and Indonesia Vision 2045 [5].

The government, through the Minister of PPN/Head of Bappenas, stated that relocating the capital city was necessary for several main reasons: Java's population was too dense, economic contribution to GDP, land conversion in Java dominated, economic equity, environmental burden problems in Jakarta, and a crisis of water availability.

There are various reasons why this move should be advantageous for Jakarta [6]: (1) it will alleviate intense road congestion; (2) it will slow down environmental degradation such as air and water pollution; (3) it will make Jakarta less vulnerable to natural disasters such as earthquakes, tsunamis, volcanoes, and floods; (4) it will reduce economic conditions and population concentration; and (5) it will mitigate land subsidence brought on by the pumping of groundwater [7].

Based on the document "Ideas of Planning and Design Criteria for the IKN" from the Ministry of Public Works and Public Housing (PUPR), the vision of the IKN of the Republic of Indonesia is to represent the excellent progress of the nation and serve as a catalyst for increasing Indonesian human civilisation. There are three key objectives: 1) reflecting the nation's identity; 2) ensuring environmental, social, and economic sustainability; 3) realising a city that is smart, modern, and of international standard [8, 9].

First, the IKN must be able to show the identity of the nation, which will be philosophically translated into Urban Design from the principles of the Indonesian state philosophy, namely Pancasila (Five Principles of the Indonesian state philosophy) [10], Bhinneka Tunggal Ika (unity in diversity) [11], NKRI (the archipelagic state of Republic Indonesia), and Gotong royong (working together). National identity is implemented in the form of morphology and city functions, spaces for community activities that encourage the principle of gotong royong (working together), and functions and containers that preserve the nation's history and culture (including Indonesia Sentris: cultural spaces, national galleries, museums, theatres, and art parks) [12].

Second, the IKN must realise social, economic, and environmental sustainability as an outcome of integrating social, economic, and environmental protection aspects [13].

Third, the IKN must also realise a smart, modern city with international standards. The IKN will become a compact city, relying on information and communication technology to achieve the goals of sustainable development (SDGs). The expectations set for the IKN will be achieved through regional development plans, economic growth, social progress, personnel, territory, environmental conservation and management, equipment, displaced, and security and defense.

Based on the safety strategy, there are at least three technical principles for the IKN that can be connected to security. These are: designing urban infrastructure with a rotating and flexible system; creating a city that is secure, convenient, and reasonably priced for all inhabitants, including children, women, elderly, and people with impairments; and developing a city that is efficient and productive using technology.

Even though the IKN doesn't have a comprehensive plan for security policy, all of these concepts can contribute to safety. The IKN Master Plan's approach to safety is more directly related to creating a prosperous city, ensuring accessibility to necessary facilities, and considering a comprehensive tenancy ratio when applying these three principles of direction [14].

In addition, the vision for the IKN is smart, green, beautiful, and sustainable, translated through the development of cities that are in harmony with nature through the concept of a forest city and a smart city [7]. One transformation from this concept is an emphasis on a 50% spatial pattern for green open space, which will also prioritise improving ecosystem quality, protection and conservation, especially in areas with high conservation value (HCV).

PPN/Bappenas, in the National Dialogue on the Transfer of the National Capital in Jakarta, explained that there would be four zones in the new capital city. The four zones are the central government core area (KIP), the State Capital area (K-IKN), the expansion area for the State Capital (KP-IKN₁), and the expansion area for the State Capital (KP-IKN₂). The central government core area is planned to cover an area of 5,600 hectares (ha). It will consist of the state palace, offices of state institutions, cultural gardens, and botanical gardens.

Then, the state capital area (K-IKN) will be built on 40,000 ha. This area will comprise housing for the State Civil Apparatus (ASN), education and health facilities, universities, science and techno-parks, hi-tech and clean industries, research and development centers, convention buildings, sports centers, and museums.

KP-IKN₁ will cover an area of about 200,000 ha, and will consist of a national park, orangutan conservation and zoo, non-ASN settlements, airports, and ports. Lastly, KP-IKN₂ will occupy more than 200,000 ha, containing a metropolitan area and developments with adjacent provinces. The government plans that the new government area will not be as expansive as a metro city [6].

The IKN will require approximately 256,000 ha of land, with a core city area of 56,180.87 ha and a government center of 5,600 ha [14]. The map of the location plan for the National Capital City and the zoning plan for the new capital city is shown in Figure 1.

One of the pressing issues faced by the new IKN is the problem of obtaining raw water for drinking purposes. Currently, only 28% of the people in the surrounding area have access to clean water [15, 16]. Moreover, the government aspires that the drinking water for the IKN should be of tap water quality [17]. However, the potential of existing water resources (SDA) is still limited, necessitating alternative sources of raw water to provide drinking water for the IKN.

The research question in this study is, "What are the alternative sources of water availability to ensure the sustainability of water resources in IKN?" This paper investigates the plan for raw water needs, alternative sources of raw water, analysis of the sustainability of raw water sources, and several alternatives to support the sustainability of raw water supply. The novelty of this study lies in presenting several alternatives to support the sustainability of the raw water supply for IKN's drinking water. Given its geographical proximity to the proposed new capital city, Penajam Paser Utara becomes a focal point for understanding how integrated water resources management principles can be applied within the IKN framework and when planning a new urban center. Hence, this study was conducted in Penajam Paser Utara in East Kalimantan Province, Indonesia, in 2022.

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Figure 1. The IKN zoning plan

Calculating the total raw water in each PDAM has added a factor to the amount of water wasted during the processing. Estimates of the total drinking water supply (SPAM) and the total raw water demand in the area around IKN in 2023 can be seen in Table 3. The total drinking water supply demand in Kutai Kartanegara Regency, North Penajam Paser Regency, Paser Regency, Balikpapan City, and Samarinda City until 2023 is 9,757 l.s^-1. Water loss during water purification is estimated at 10% [26]. The total raw water needs for the regencies/cities around IKN are Kutai Kartanegara Regency, North Penajam Paser Regency, Paser Regency, Balikpapan City, and Samarinda City until the year 2023 is 10,732 l.s^-1. For the New Capital City, it is estimated that 1.5 million state civil apparatus (ASN) will be transferred. It is assumed that each ASN family consists of four people. Then the number of new IKN will reach around 6 million people, and it is planned to occur in 2023. The following assumptions are made: using 150 l/person/day of drinking water, the rate of water loss/leakage is 20%, and the peak discharge factor of 1.2. To calculate the need for drinking water supply, the results of the calculation of the estimated drinking water demands and raw water needs in 2023 are shown in Table 4.

Table 3. Estimated total drinking water supply and raw water demands in regency/city areas around IKN in 2023

Table 4. Estimated drinking water and raw water demands for IKN (the basic year 2023)

According to the calculations, IKN will need 15,000 l.s^-1 of drinking water during the planned year 2023, while 16,500 l.s^-1 would be needed for raw water. Thus, for the drinking water supply to IKN and its adjacent regencies/cities, namely Kutai Kartanegara Regency, Penajam Paser Utara Regency, Paser Regency, Balikpapan City, and Samarinda City, in the planning year 2023, a total raw water supply of 27,232 l.s^-1 is required. The geometric method calculates the projected raw water needs for drinking water supply in the IKN area and the adjacent regencies/cities. Assuming the population growth rate (in 2019) is for Kutai Kartanegara Regency at 1.97%, Penajam Paser Utara Regency at 1.05%, Paser Regency at 1.89%, Balikpapan City at 1.41%, Samarinda City at 1.58%, and IKN at 1.5% [4]. The results of the calculation of the natural water need for IKN and adjacent regencies/cities for the next 50 (fifty) years are shown in Figure 2. From the calculation results, it is seen that the estimated raw water needs for IKN and its adjacents in 2023, 2033, 2043, 2053, 2063, and the year 2073 are 27,232 l.s^-1, 31,828 l.s^-1, 37,211 l.s^-1, 43,522 l.s^-1, 50,918 l.s^-1, and 59,594 l.s^-1. The results of the calculation of the projected raw water need for IKN and adjacent regencies/cities for the next 50 (fifty) years are shown in Table 5 and Figure 2. From the calculation results, it is seen that the estimated raw water needs for IKN and its adjacent in 2023, 2033, 2043, 2053, 2063, and the year 2073 are 27,232 l.s^-1, 31,828 l.s^-1, 37,211 l.s^-1, 43,522 l.s^-1, 50,918 l.s^-1, and 59,594 l.s^-1.

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Figure 2. Projected raw water demands for drinking water supply in IKN areas and adjacent regencies/cities

3.2 The potential and planning for the development of natural resources in the IKN and adjacent area

According to the Kalimantan III River Basin Center (BWS), in East Kalimantan Province, six infrastructures have already been sources of raw water extraction. The six sources of raw water are the Manggar Dam in Balikpapan, with a capacity of 14.2 Mm³;( million cubic meter) the Teritip Dam in Balikpapan, with a capacity of 2.43 Mm³; the Aji Raden Embung in Balikpapan, with a capacity of 0.49 Mm³, the Samboja Dam in Kabupaten Kutai Kartanegara with a capacity of 5.09 Mm³, the Mahakam River Kalhol Intake with a capacity of 0.02 Mm³, and the Lempake Dam in Samarinda with a capacity of 0.67 Mm³ [27]. The five existing water resource infrastructures have a total raw water potential of 4,827 l.d^-1 [28, 29]. To support providing clean water for IKN, the government will build eight infrastructures for raw water sources included in the plan to support raw water in East Kalimantan. The eight infrastructures, namely the Sepaku-Semoi Dam, have a total raw water potential of 2,500 l.d^-1, for the supply of raw water for the City of Balikpapan (Sepaku) of 500 l.d^-1, and the raw water supply for IKN of 2,000 l.d^-1. The Batu Lepek Dam has a raw water potential of 14,500 l.s^-1, will be intended for raw water supply to IKN of 13,000 l.s^-1, and to meet the shortage of raw water supply in Kutai Kartanegara Regency of 1,500 l.s^-1. The Itchi Dam, with a raw water potential of 4,000 l.s^-1, is intended for IKN's raw water supply of 3,600 l.s^-1 and to meet the shortage of raw water supply for North Penajam Paser Regency of 400 l.s^-1. Lambakan Dam, with a raw water potential of 5,000 l.s^-1, is intended for IKN's raw water supply of 3,865 l.s^-1 and to meet the shortage of raw water supply in Paser Regency of 1,135 l.s^-1. The raw water intake from the Loa Kulu Intake of 2,000 l.s^-1 is used for the IKN raw water supply of 1,200 l.s^-1 and the Samarinda City raw water supply of 800 l.s^-1. Meanwhile, the Selamatyu Dam at 3,950 l.s^-1, the Safiak Dam at l.s^-1, and the Beruas Dam at 1,100 l.s^-1 are used for IKN raw water supply [28, 30]. From a number of these infrastructures, the government prioritizes the construction of the Batu Lepek dam in Kutai Kartanegara Regency, which is planned to be auctioned in 2020 as the main raw water supply for the location of the national capital city. The Batu Lepek dam's capacity will supply raw water needs in perspective IKN with a total of 14,300 l.s^-1. The potential of existing water resources and plans for developing natural resources in the IKN area and adjacent regencies/cities can be seen in Table 6. The Water Resources Infrastructure Plan in IKN can be seen in Figure 3. This table shows that the total raw water potential from the existing SDA infrastructure and the planned SDA infrastructure to be built is 38,777 l.s^-1. Based on the author's analysis, the scenario of raw water supply for IKN taken from the natural resource infrastructure to be built can be seen as shown in Figure 4. If the total potential of water resources from the existing infrastructure and the infrastructure to be built is plotted with the projected water demand for the IKN and the districts/cities around the IKN for the next 50 years, a graph will be obtained as shown in Figure 5.

Several limitations in estimating raw water needs, among others, barriers to the productivity of water treatment plants, the quantity of groundwater and surface water [31]. Likewise with uncertainties that can affect predictions of raw water demand such as global climate change, longevity of water supply infrastructure, land use and agricultural conditions, food markets, spatial developments, economic developments, future technologies, and societal values in the world [32].

3.3 Sustainability analysis of IKN for raw water sources

Suppose the total potential of water resources from existing infrastructure and infrastructure to be built is plotted with the projected water demand for IKN and regencies/cities around IKN for the next 50 years. A graph will be obtained, as shown in Figure 5. Suppose it is assumed that all-natural resource infrastructure plans have been built in Figure 5. in 2023. In that case, there is still a surplus of the raw water supply of 11,545 l.s^-1, and if there is no additional potential for raw water, after 2045, it is estimated that there will be a raw water supply deficit. If it is assumed that in 2023 only 80% of the total raw water potential can be utilized, in 2023, there will still be a raw water surplus of 3,790 l.s^-1. If there is no additional raw water potential, it is estimated that after 2031 there will be a raw water deficit. There will be a raw water deficit of 3,966 l.s^-1 in 2023 if only 60% of the total raw water potential development plan can be used. As a result, in the long term, it is necessary to find alternative potential raw water sources for IKN and the adjacent regencies/cities.

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Figure 3. Water resources infrastructure plan at IKN

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Figure 4. A scenario of raw water supply for IKN

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Figure 5. Graph of raw water demand projection for drinking water supply in IKN areas and surface potential of existing natural resources infrastructure and infrastructure plans to be built

3.4 Long-term alternatives to fulfill the raw water supply of IKN

One of the large raw water potentials that can still utilize is from the Mahakam River through the Loa Kulu intake, and it's just that the distance is relatively far, around 146 km [33]. Several other alternatives for supplying IKN raw water include the use of Rainwater for domestic purposes, the use of groundwater, the use of recycling wastewater into clean water, and the desalination of seawater into drinking water [34].

3.4.1 Raw water source from the Mahakam River

The Mahakam River is the name of the largest river in the province of East Kalimantan, which discharges into the Makassar Strait. This river, which has a length of 980 km and an estimated catchment area of greater than 77,800 km², is also one of the largest in Indonesia [35]. This river spans about 920 km and crosses the West Kutai Regency upstream to the Kutai Kartanegara Regency and Samarinda City downstream. The average flow rate is 2,500 l.s^-1. In contrast, the maximum flow rate is 3,250 l.s^-1 [33]. Thus this river can be used as an alternative source of raw water for IKN. One of the problems is that the distance between the intake location and the IKN location is quite far, which is about 146 km, and it will require a significant investment. In addition, the water quality of the Mahakam River begins to be polluted by both domestic and industrial wastewater [36].

3.4.2 Alternative utilization of groundwater for domestic purposes

Regarding topography, the IKN area is a folded hill composed of sandstone and clay, with coal inserted between the clay stones. The western part is a fold with a rock slope to the west, and the east side is a folded part with a rock slope to the east. The west-southeast anticline axis forms the lowlands for the IKN, which are often flooded parts. With such a position, groundwater aquifers tend to tilt outward from IKN candidates, and it is unlikely that groundwater will be found in the center of the IKN; groundwater will tend to be abundant on the west side of the IKN, which will come out as springs. Therefore, more tributaries will emerge from the west side. Shallow groundwater potential is still very possible in the middle of the IKN, but the potential is insignificant, only sufficient for household-scale needs. Still, it is rather tricky for large quantities or requires more in-depth information, especially for those that provide aquifer data in a relatively low position. Most of the area is in the district of Sepaku and District. Loakulu has a low groundwater-carrying capacity. In Sepaku District, the area with scarce groundwater carrying capacity is 55,310.22 ha (97.5%). At the same time, the area with moderate groundwater capacity is only 1,436.41 ha (2.5%). For Loa Kulu District, the area with low groundwater carrying capacity is 18,406.21 Ha, and this area with moderate groundwater carrying capacity is 1,155.41 ha (6.3%). All Core Areas and Core Locations of IKN have low groundwater carrying capacity. Sukaraja Village has an aquifer depth of 20-60 m with an average discharge potential of 0.7 l.s^-1, while at a depth of 0-20 m, groundwater quality has high levels of iron (Fe) with a potential discharge of 0.1 l.s^-1. Groundwater aquifers at a depth of 60 -100 meter have poor groundwater quality, as evidenced by several samples of deep bore wells with a depth of 100 meter; the groundwater quality is salty with > 10,000 s.cm^-1 with a potential discharge of 0.7 l.s^-1 [37].

3.4.3 Alternative utilization of wastewater reclamation

Urban wastewater is potential raw water that can be used to be reprocessed and utilised for various purposes because about 80-90% of the clean water used will become wastewater. Before being discharged into the environment, wastewater must be treated until it meets the applicable quality standards. It can be utilised or reused according to its designation if further processed. Several applications of wastewater recycling are used for various purposes, including agricultural or landscape irrigation, industrial use, groundwater recharge, and to supply clean water and general purposes, for example, flushing and fire fighting water and others [38]. The drought that dominated the millennium (2000–2009) heightened public interest in desalination and water recycling. Water reformation laws created standards for recycled water, including runoff and drinkable water rise. Brisbane has installed modernised reclaimed water treatment facilities for indirect potable reprocessing [39]. Several things need to be considered to examine several essential concepts and technologies for recycling wastewater. The first is the reliability of the treatment process (treatment process reliability), and the second is the quality of the treated water must comply with the quality standard for its purpose. One example of successful water reclamation and reuse is NEWater Factory in Singapore. Due to advancements in the membrane process, it is now technically and financially viable to enable the reclamation and reuse of water. Reclaimed water currently makes up 40% of Singapore's water supply, and the government anticipates it will eventually make up a more significant share [40]. Reclaimed water may be produced consistently and of high quality due to multi-barrier methods, including dual membrane filtering and UV disinfection, as well as a disciplined operational philosophy and extensive water quality management program [41].

3.4.4 Alternative utilization of rainwater for domestic purposes

One alternative to meet the needs of raw water in IKN so that there is no water deficit is using rainwater for domestic purposes by applying the Rain Harvesting (RWH) method. Rainwater Harvesting (RWH) has become increasingly utilised as a secondary water supply option for domestic and drinking needs due to the rising scarcity of groundwater and surface water due to human activity and climate change [42]. In rural parts of developing nations example, Vietnam, rainwater is frequently used as a natural, affordable water source because it is tastier than underground water. Increasing the utilisation of rainfall is a priority for the Vietnamese government, as evidenced by the Government Order No. 80/2014/CP on drainage and wastewater treatment, published in 2014 [43]. Two-thirds of Singapore's land area is used to collect water. Nonetheless, Singapore is striving to add 2,060.57 ha to the watershed area so that it covers 90% of its land, making it one of the few nations in the world to collect urban stormwater for drinkable use on such a big scale. The amount of rain that can be gathered and stored is constrained by the tropical nation's small size [44]. The use of rainwater is a significant potential alternative to meet the needs of raw water in the IKN because it is an area with a tropical climate located in the southeast of the Asian continent, which only has two seasons, namely the rainy season and the dry season. During the rainy season, we face abundant water, so the existing rivers cannot accommodate the amount of water, and floods occur. With high rainfall, various areas are often flooded because the capacity of rivers that divide the land has been reduced due to silting of rivers, accumulation of garbage at sluice gates, and illegal development on riverbanks [35]. Water conservation with the Roof Top RWH method has considerable potential to overcome the problem of raw water availability in IKN. Suppose the government provides a policy, so the community is willing to start water conservation efforts by harvesting rainwater in their homes and for industry, offices, hotels, shops, and others [45]. Although it has been known in Indonesia for a long time, this conservation technique has yet to be implemented thoughtfully. Many people have channeled rainwater from the roof of their houses with a paralon system; unfortunately, the water is directly discharged into the gutter. If rainwater from the roof is accommodated and collected for use, it will be able to reduce the water crisis.

3.4.5 Desalination of saltwater to freshwater

Another alternative to meet the needs of raw water in IKN is the application of desalination for saltwater to the freshwater method. In recent years, desalination technology and the prospect of desalination technology reduced water scarcity increasingly. Some countries have used desalination technology for commercial water supply, as shown in Table 7.

Table 7. Ranking of the top 10 countries using desalination technology [46]

The cost of producing SWRO desalinated water with a capacity of fewer than 100 million liters per day (1,000 m³.l^-1) is relatively high, but for a larger capacity of 100 million liters per day (Mld) the cost of water production is lower. The optimal size for SWRO desalination plants is 100-200 Mld. For the new Installation, SWRO has recorded total production in the range of US$ 0.5 – 0.8 per m³. Newer SWRO installations generally produce water at a much lower production cost. The new SWRO installation has used energy recovery device technology (ERD) so that it can save more on energy costs [47].