Analysis of Surface Water Availability and Projection of Domestic Water Demand in The Logawa Sub-Watershed 2030

Water is a vital element that is used to meet human needs such as domestic and non-domestic activities (agriculture, fisheries, tourism, and industry). The more human activities carried out, the greater the amount of water needed. Therefore, it is necessary to analyze the availability and demand for water to determine the conditions of shortage and excess water to meet future water needs. The method used in this research was the quantitative descriptive method with the study area unit covering all parts of the Logawa Sub-Watershed. The research sample was taken using the purposive sampling method with data collection techniques including secondary data in the form of literature studies and related institutions and primary data in the form of direct observations in the field. Data analysis was determined by the discharge duration curve formula to obtain a reliable discharge and calculate the water demand in each sector. The results of the study show that the availability of water in the Logawa Sub-Watershed can suffice the water needs of the domestic and non-domestic sectors (agriculture and livestock) in 2023 and domestic water needs in 2030.


Introduction
Ease of access to water is one of the target objects of Sustainable Development Goals (SDGs) because it is a basic need that is used to meet human needs.The distribution of water is quite varied.There are areas with high water availability, while other areas do not have much water at all.This is influenced by variations in landform.Beside that, the amount of water is also influenced by the utilization intensity by humans.Water is used for various purposes, such as domestic and non -domestic needs (agriculture, fisheries, tourism, and industry).The increase in human activities results in a higher water demand.Total water availability is relatively constant, but demand for water increases every year, so effective water management becomes crucial to ensure optimal utilization.In Indonesia, several legal instruments regulate water governance, such as Law Number 32 of 2009 concerning Environmental Management and Law Number 17 of 2019 concerning Water Resources.In addition, The Government Regulation of the Republic of Indonesia Number 37 of 2012 also explains that water resource management can also be carried out by regional governments, so that local governments are given the authority to create legal instruments that regulate policies for managing water resources in their regions.
A watershed is an area bounded by hill ridges, which has three functions: water storage, catching, and distributing water [1].Based on their carrying capacity, watersheds are categorized into two categories: rehabilitated and maintained watersheds.Watersheds that are rehabilitated are those whose conditions are not functioning optimally, whereas maintained watersheds are those functioning at their optimal capacity [2].According to KLHK [3] there are 37,721 maintained watersheds and 4,489 rehabilitated watersheds in Indonesia.Meanwhile, among the 4,489 rehabilitated watersheds, there are 1313 (2024) 012013 IOP Publishing doi:10.1088/1755-1315/1313/1/012013 2 108 priority watersheds.On Java Island, one example of these critical watersheds is the Serayu Watershed.This location of this research was conducted in the Logawa Sub-Watershed, which is part of the Serayu Watershed.The Logawa Sub-Watershed is an area drained by the Logawa River, with its upstream and downstream parts located in the Banyumas Regency (Figure 1).The area of this Sub-Watershed is 30,956.80hectares.The upstream of this Sub-Watershed is located on the slopes of Mount Slamet and flows downstream into the Serayu River.Administratively, there are 13 sub-districts located in this Sub-Watershed, namely Purwokerto Barat, Purwokerto Timur, Purwokerto Utara, Purwokerto Selatan, Baturraden, Ajibarang, Rawalo, Cilongok, Karanglewas, Kedungbanteng, Patikraja, Pekuncen, and Purwojati.Based on the result of satellite imagery, the land cover around the Logawa Sub-Watershed includes primary dryland forests, secondary dryland forests, plantation forests, mixed dryland agricultural areas, paddy fields, bodies of water, and open land areas.
Water resources in the Logawa Sub-Watershed can be evaluated based on their quantity and quality.Suroso's research [4] indicates that the Logawa River's capacity can still handle the flood discharge that flows with the Patikraja area, which is located downstream at an elevation of 1.000-3,000 meters.This region is classified as flood prone.In addition, studies conducted by Umam and Wahyuningsih [5] using temperature, total dissolved solid (TDS), total suspended solid (TSS), dissolved oxygen (DO), chemical oxygen demand (COD), pH, nitrate, and phosphate also showed that the water quality was comparatively good, meaning that it was sufficient to support the gastropod biota's existence in the river.
The Purwokerto and Purbalingga Groundwater Basin systems contribute to the upstream area of the Logawa Sub-Watershed (Figure 2).The Logawa Sub-Watershed's groundwater potential varies depending on the hydrogeological features of aquifers.Both the confined and the unconfined aquifer in the upstream region have rare groundwater potential.Given the high and medium aquifer productivity in the middle region, there is a great potential for groundwater.Aquifers with low productivity are found in several downstream areas, which are among the few areas with little substantial local productivity.The population growth in the sub-districts situated in the Logawa Sub-Watershed is known to be rather significant, based on the publication of the Banyumas Regency Central Statistics Agency (BPS) in Figure 3.The sub-district with the largest growth rise, Kedungbanteng, has a value of 1.32%.Meanwhile, the sub-districts with the lowest population growth, Purwokerto Barat, Purwokerto Selatan, and Purwokerto Utara, have values of 0.59%.The water supply in the Logawa Sub-Watershed may decline if population growth rates keep rising and sustainable resource management is not implemented.However, based on the interviews, most people use springs and groundwater for household needs, therefore non -domestic activities would further damage the surface water conditions in the Logawa Sub-Watershed.Water resources in the Logawa Sub-Watershed tend to be utilized for agricultural irrigation.This study's goal is to ascertain how the Logawa Sub-Watershed's surface water supply and demand for residential and non -domestic water will balance out in the years to come, or until 2030.To accommodate future water demands, it is necessary to conduct a study of both the demand and supply for surface water to comprehend the conditions of drought or excess water.The results of this analysis can later be used as a recommendation or reference for policymaking and drafting spatial plans (RTRW) based on sustainable development in the Logawa Sub-Watershed.

Methods
The method used in this research is the quantitative descriptive method, with the study area covering the entire region of the Logawa Sub-Watershed.The data utilized for this study comprises both secondary and primary data.Secondary data were obtained from literature reviews and water resource management institutions in the Banyumas Regency (BPSDA Serayu Citanduy).Primary data were gathered through direct field observations and interviews.The sampling locations for observations and interviews were determined using purposive sampling methods, considering the morphology of the Logawa Sub-Watershed, which is divided into upstream, middle, and downstream regions.The distance to surface water sources or rivers was considered in selecting the sampling locations for observations and interviews (Figure 4).

Water Availability
The data on surface water availability in the Logawa Sub-Watershed was obtained from secondary data held by the Serayu Citanduy Water Resources Management Agency (BPSDA Serayu -Citandy).The secondary data consists of daily discharge data from several dams.The discharge data used was the amount of discharge from three dams located in the Logawa Sub-Watershed, namely Banjaran I, Banjaran II, and Kediri dams.The discharge data was processed to generate monthly discharge values for 2010-2022.
The accumulated discharge data was processed using the flow duration curve method to obtain the dependable discharge.The dependable discharge represents the flow that will be available during the year with a certain level of risk of failure [7].This dependable discharge serves as the data for surface water availability in the Logawa Sub-Watershed.The calculation of the dependable discharge was carried out by using SNI 6738:2015 on the Calculation of Dependable Discharge and Flow Duration Curves.The discharge data is organized from maximum to minimum values in a mass curve or table.If presented as a curve, the ordinate represents the flow discharge, whereas the abscissa represents time.If presented in table form, the monthly discharge data is sorted from the largest to the smallest values to obtain the data ranking and the required data quantity for the calculation.The formula for calculating water availability is given in Equation (1).
With: P(X ≥ x) : The probability of the occurrence of variable X being equal to or greater than m 3 /s m : Data ranking n : Amount of data X : Discharge data series x : The dependable discharge if the probability corresponds to its purpose, for example, P (X ≥ Q80%) = 0.8

Water Demand
The water demand in the Logawa Sub-Watershed is divided into domestic water demand and nondomestic water demand, which includes the agricultural and livestock sectors.The water demand for agriculture was determined based on the parameter of irrigated agricultural land area.The water demand for livestock was determined based on the parameter of the number of livestock.This data was obtained from publications by the Central Statistics Agency (BPS).The domestic water demand was obtained using the parameter of the population size (Table 1).The population data was obtained from publications by the Central Statistics Agency (BPS).The domestic water demand in the Logawa Sub-Watershed was projected until 2030 using data from the period between 2010 and 2022.The projected population size was used to obtain the projected domestic water demand in the Logawa Sub-Watershed until 2030.1).The total water demand of the Logawa Sub-Watershed is the accumulation of water demands from each sector.

Domestic Water Demand.
The domestic water demand indicates the need for clean water used for daily activities such as consumption, cooking, washing, bathing, and watering plants.The calculation of domestic water demand is based on the population size and the standard water requ irement per person per day.The population size was determined using the weighted average population.The standard water requirement per person per day follows SNI 6728.1:2015due to its more detailed classification, while the calculation formula is based on SNI 19 ) provides information on the population in administrative units of subdistricts.However, the units in this research were based on the boundaries of the Logawa Sub-Watershed.The population in the Logawa Sub-Watershed area was derived using a weighted average method.This method assumes an even distribution of the population in each sub-district, allowing the population to be estimated based on the ratio of the sub-district's area to the Logawa Sub-Watershed's total area.Equation ( 5) applies the following for calculating the weighted average.

Pw = Pa × Area of watershed
Area of administrative region With: Pw : Population in the watershed area Pa : Population in the administrative unit

Population Projection for Domestic Water Demand Projection
The future will see a continued rise in domestic water demand in tandem with population growth.To gauge this, population projections have been made up to 2030 to estimate domestic water demand in the upcoming years.There are two frequently employed techniques for predicting population figures to determine water demand: the exponential and arithmetic methods.The exponential approach illustrates a gradual population increase over the years, facilitating the estimation of potential domestic water demand [11].On the other hand, the arithmetic method is appropriate when t he population growth rate is less than 2%, which is the scenario in the Banyumas Regency.The arithmetic method presumes a consistent annual population growth.Equation ( 6) contains the formula for the exponential method, and equation ( 7) encompasses the arithmetic method's calculation formula.Source: Guidelines for Calculating Population and Labor Force Projections [12] Standard deviation calculations were carried out on both projection methods to decide which method was more favorable.The preferred projection method was the one with the lowest standard deviation value [13].This value signified the degree of variance between the projected population and the current population.According to the standard deviation computations, the arithmetic projection method showed a value of 16,32 while the exponential projection yielded a value of 19,97.Consequently, the chosen population projection method was the arithmetic one.

Demand and Availability of Surface Water Balance
Water balance analysis was performed to assess the extent of surplus or deficit in the availability and demand of water in the Logawa Sub-Watershed.A water balance chart was employed to conduct an analysis of the equilibrium between water demand and water availability in the Logawa Sub-Watershed.The water balance chart comprises the values of water demand and water availability from the year 2010 to 2022.Furthermore, the contrast in these values is illustrated to display the equilibrium between them.The value of water availability obtained from the calculation of dependable discharge was visualized in a flow duration curve to illustrate the discharge probability.The level of the dependable discharge is considered in ensuring the fulfilment of future water needs.

Water Availability
The availability of water in the Logawa Sub-Watershed was assessed using secondary data on river discharge in the Logawa Sub-Watershed obtained from BPSDA Serayu Citanduy in 2010 -2022.From this data, probability values of 60 and 80 (P80 and P60) were obtained.The reason probability values were used to establish the value of water availability is that there will be a risk of failure and deviation from planning calculations [14], so by using these reliable discharge values, this value was available in the field.According to [15], probability values are also used for analysis, because hydrological conditions can occur with various changes and are not dependent on time.
The reliable discharge value of 60 (P60) is larger than the discharge value with an 80 probability (P80) (Figure 5).During the rainy season (September -March), the water availability in the Logawa Sub-Watershed is greater than in the dry season (April -August).This condition occurs because rainfall during the rainy season is higher than the dry season so rainwater can fill surface water bodies.However, in September the reliable discharge is lower than in other months.This might occur because the rainfall during September is relatively low.From the outcome of the interviews, it is also known that there are some places in the Logawa Sub-Watershed where water is not available during the dry season, which means that meteorological conditions significantly influence surface water availability.

Water Demand
Water demand is the amount of water used for various human activities in an area [16].Water resources utilization in the Logawa Sub-Watershed consists of the domestic and non-domestic sectors (agriculture and livestock).A good water supply can fulfill water demand for each sector in the watershed so that drought does not occur.In this research site, the highest water demand comes from the irrigated agricultural sector which requires 144 billion liters/year (Figure 6).This is because Banyumas Regency is one of the Central Java granaries, so the agricultural land is very wide.Paddy fields are the main asset for rice production, especially in irrigated rice fields, river water is important as a water supply for rice production.10 Domestic water utilization is used for drinking, washing, house cleaning, pool water, watering gardens, etcetera.In the Logawa Sub-Watershed, the domestic water demand is 17 billion liters/year, equivalent to the population living in the Logawa Sub-Watershed.The increasing population years ahead will cause domestic needs to be higher in value.Water demand for water for livestock is the lowest, the utilization is for feed, processing livestock products, bathing livestock, and others.The total water requirement for animal husbandry is 1.2 billion liters/year, which is not too high because the amount of livestock is not that massive.

Domestic Water Demand.
The domestic water demand in the Logawa Sub-Watershed in 2010 -2030 was estimated based on population data from 2010 to 2022, and domestic water demand data for 2023 -2030 was projected based on population projections.The population of the Logawa Sub-Watershed is projected to increase annually until 2030.This is due to the positive population growth in the Logawa Sub-Watershed from 2010 to 2022, with an average annual growth rate of 0.0095 (Table 2).
The total domestic water demand in the Logawa Sub-Watershed during the first 13-year period (2010 -2022) experienced fluctuations influenced by its population (Figure 7).In the first 4 years (2010 -2013), the domestic water demand steadily increased from 15,386.11 million liters/year to 16,738.07 million liters/year, in line with the continuous growth of the population (Table 3).However, in 2014, the population growth rate turned negative, indicating a significant decrease in the population.Crude death rates in several sub-districts of the Logawa Sub-Watershed were relatively high compared to other years [17].Consequently, the domestic water demand also decreased by 773.67 million liters/year.
A significant increase in domestic water demand occurred during 2015 -2017.In 2017, the water demand for domestic activities reached 17,709.30 million liters/year.The most significant demand in domestic water took place in 2016, amounting to an extra 940.59 million liters/year annually.This uptick in water demand is linked to the substantial growth rate ratio of the Logawa Sub-Watershed Population between 2015 and 2016, which stood at 0.046 (Table 2).Meanwhile, the domestic water demand for the period of 2018 to 2020 continued to decrease, ranging from 17,579.10 to 16,391.92 million liters/year (Figure 7).This decrease was directly proportional to the decline in the population of the Logawa Sub-Watershed due to a negative population growth rate.The decrease in population growth can be attributed to the impact of the COVID-19 pandemic that affected Indonesia from 2019 to 2020.After 2020, the domestic water demand continued to increase until 2022, reaching 17,215 million liters per year and was then projected.The projection results for the period of 2022 to 2030 indicated a population increase of 4.3 percent in the Logawa Sub-Watershed and an 8.5 percent increase in domestic IOP Publishing doi:10.1088/1755-1315/1313/1/01201311 water demand.In 2030, the domestic water demand within the Logawa Sub-Watershed amounted to 18,677.91 million liters per year (Figure 7).These findings demonstrate a direct correlation between the increase in domestic water demand and population growth.The carrying capacity of water resources is controlled and monitored periodically at river dams.The need for irrigation water considers the area of irrigated land, standard irrigation water requirements, and cropping intensity [18].The total area of irrigated land in the Logawa Sub-Watershed is 6.984 ha, the area is divided into 13 sub-districts consisting of upstream, middle, and downstream morphology.
The difference in the volume of irrigation water demand in each sub-district is influenced by water distribution factors, regional characteristics, and the size of the administrative area.In Figure 8, it is known that the Cilongok Sub-District is the sub-district with the highest water demand because it has an area of almost 40 percent of the entire Logawa Sub-Watershed area.Meanwhile, the Patikraja Sub-District with a relatively small area is in the downstream area and is an estuary area, so it supports a large supply of water with a high soil fertility factor.In addition to irrigated agricultural land, there are also non-irrigated agricultural land or dry agricultural land with the water distribution factor as the most influential consideration.The total need for irrigation water in the Logawa Sub-Watershed is 144.819 million liters/year.This value was obtained through the mechanism of calculating the harvest period twice with a cropping pattern in one year to complete the water supply condition s.External factors that have an impact on reducing the volume of water availability such as the result of water theft and damage to embankments are the concern of farmer groups and irrigation canal managers.

Livestock Water Demand.
Livestock farming is an emerging sector in the Logawa Sub-Watershed.The water requirements for livestock farming in this area depend on the types and quantity of livestock present.Livestock species raised for agricultural activities in this region include cattle, buffaloes, goats, sheep, pigs, and poultry.Each type of livestock has different water supply needs, leading to variations in water demand.The estimated water requirements for the livestock sector in the Logawa Sub-Watershed for the year 2022 are presented in Table 3.The total annual water requirement for livestock farming in the Logawa Sub-Watershed reaches 1,121,493,670 liters.This amount is predominantly attributed to the water consumption of poultry, which accounts for 950,832,300 liters per year, or 84 percent of the total water needs in the livestock sector.The high-water requirement for poultry is driven by the rising market demand for meat consumption.According to Mastuti et al [19], the expensive price of beef is one of the factors contributing to the rising trend of poultry farming as a substitution for providing valuable animal protein.
In the Logawa Sub-Watershed, the Baturraden Sub-District exhibits the highest water requirements in the context of livestock farming, reaching a total of 254,143,003 liters per year (Figure 9).This is reinforced by the favorable climatic conditions and geographical characteristics that support livestock growth in the Baturraden Sub-District [20].

Demand and Availability of Surface Water Balance
The balance of demand and availability of surface water is known by comparing the results of calculations between demand and availability of surface water.Ensuring a balance between the demand for and accessibility of surface water is crucial for assessing the state of water availability to meet the water requirements in a particular area.Achieving an ideal water balance is possible when the quantity of available water matches the quantity of water required [20].To obtain this balance, we need a policy that oversees the use and availability, because according to [21], a policy regarding water resources will impact the state of the water.The outcomes of the assessment regarding the balance of demand and availability of surface water in the Logawa watershed in 2022 are as follows (Table 4).Based on the results of calculating the balance of demand and availability of surface water in the Logawa Sub-Watershed in 2022, a surplus of 2,673,038 billion liters in one year can be seen.The largest demand for water comes from the agricultural sector with the required amount of water reaching 144 billion liters/year or 87 percent of the total water demand.This is due to the large area of irrigated rice fields in the Logawa Sub-Watershed, reaching 6.984 ha.In general, the water discharge present in the Logawa River in 2022 will still be able to fulfill the requirements of the domestic, agricultural, and livestock fields within the Logawa Sub-Watershed with a ratio of total demand to water availability of 0.006 percent.

Flow Duration Curve
The flow duration curve is used to represent the frequency of discharge events from a set of time periods [22].The shape of the flow duration curve can also show the flow characteristics of a watershed of longperiod virgin where a sharper slope indicates the percentage of flow with a large discharge value.The debit value will affect the average debit value and the skewness value of the data distribution.The skewness value may be elevated by the contribution of discharges during the flood period.According to Figure 10, there is a decreased likelihood (7.14%) of finding the discharge distribution of more than 1,000 m 3 /s.The flow duration curve, which was used to determine the Logawa Sub-Watershed's primary discharge, indicates a propensity for water discharges to be between 60% and 80% less than 400 m 3 /s.11, it is known that the difference between water availability and water demand for the Logawa Sub-Watershed from 2010-2022 is positive.That is the availability of water is always higher than the water demand.During that time, annual water demand in the Logawa Sub-Watershed is fulfilled.The calculation of water demand in this water balance is only intended for domestic water needs so the value is smaller than the total water demand.The outcome of interviews with residents indicated that the use of river water for daily needs is mostly used for washing only, while for consumption needs spring water or groundwater is used.The cause is unsuitability of river water for consumption by resident.Furthermore, the condition of abundant availability of river water is used more by residents for irrigation.Irrigation is achieved by diverting water from the main river to the adjacent agricultural fields.

Conclusion
The analysis results show that the availability of surface water in the Logawa Sub-Watershed sufficient the needs of the domestic and non-domestic sectors (agriculture and livestock).In 2022 the availability of water will be equal to 2,673,201 billion liters/year and the need is 163.255 billion liters/year.The difference between demand and availability is 2,673,038 billion liters/year.There is a surplus of surface water in the Logawa Sub-Watershed.
Demand to meet domestic water needs in 2022 -2030 continues to increase, this is because the results of population projections show that there is an increase in population, so domestic water needs also increase.In 2022 the total domestic water demand was 17,215 million liters/year, and the projection calculation results for 2030 are 18,677 million liters/year.Based on the projection results, it shows that water availability in 2030 is 5,119.55 billion liters/year, so the difference between domestic demand and water availability in 2030 is 5,100.88 billion liters/year.This condition shows that surface water is capable of meeting domestic water needs in the Logawa Sub-Watershed.

Figure 1 .
Figure 1.Map of the Research Location: Logawa Sub-Watershed Banyumas, Central Java Source: Data Processed from DEMNAS and Map of Rupa Bumi Indonesia

3 Figure 2 .
Figure 2. Logawa Sub-Watershed Aquifer Productivity Map Source: Data Processed from the Geology Agency 2018

Figure 3 .
Figure 3. Population Growth Rate by Sub-Districts in Logawa Watershed Source: Data Processed from the Banyumas Regency in Figures 2023

Figure 4 .
Figure 4. Observations and Interviews Sample Location Map Source: Data Processed from DEMNAS and Map of Rupa Bumi Indonesia

Figure 6 .
Figure 6.Graph of Sectoral Water Demand of the Logawa Sub-Watershed in 2022 Source: Data Processed from the Banyumas Regency in Figures 2023

Figure 7 .
Figure 7. Graph of Domestic Water Demand of Logawa Sub-Watershed in 2010 -2030 Source: Data Processed from the Banyumas Regency in Figures 20233.2.2.Irrigation WaterDemand.The use of river flow in the Logawa Sub-Watershed based on interview results was prioritized for agricultural water needs, namely through irrigation canals.The carrying capacity of water resources is controlled and monitored periodically at river dams.The need for irrigation water considers the area of irrigated land, standard irrigation water requirements, and cropping intensity[18].The total area of irrigated land in the Logawa Sub-Watershed is 6.984 ha, the area is divided into 13 sub-districts consisting of upstream, middle, and downstream morphology.The difference in the volume of irrigation water demand in each sub-district is influenced by water distribution factors, regional characteristics, and the size of the administrative area.In Figure8, it is known that the Cilongok Sub-District is the sub-district with the highest water demand because it has an area of almost 40 percent of the entire Logawa Sub-Watershed area.Meanwhile, the Patikraja Sub-District with a relatively small area is in the downstream area and is an estuary area, so it supports a large supply of water with a high soil fertility factor.In addition to irrigated agricultural land, there are also non-irrigated agricultural land or dry agricultural land with the water distribution factor as the most influential consideration.
2.2.Irrigation Water Demand.The use of river flow in the Logawa Sub-Watershed based on interview results was prioritized for agricultural water needs, namely through irrigation canals.

Figure 8 .
Figure 8. Graph of Agricultural Water Needs per Sub-District in the Logawa Sub-Watershed in 2022 Source: Data Processed from the Banyumas Regency in Figures 2023

Figure 9 .
Figure 9. Graph of Livestock Water Demand per Sub-District in the Logawa Sub-Watershed in 2022 Source: Data Processed from the Banyumas Regency in Figures 2023

Table 1 .
Standard Water Requirements for Each Allocation Source: Data Processed from SNI 19-6728.1-2002 and SNI 6728.1:2015The domestic, agricultural, and livestock water demands have different water usage standards.The water usage standards for each demand refer to SNI 19-6728.1-2002 and SNI 6728.1:2015(Table [10]8..The calculation formula for domestic water demand is as follows in equation(2).The irrigation water requirement is a component of the water demand in the agricultural sector.Water is the primary factor in the diversification and rice production, inadequate irrigation water results in water stress on plants and reduced yields[10].The irrigation water requirement was obtained using the area of irrigated land as its parameter.The area of irrigated land, particularly paddy fields, was acquired through land cover maps sourced from the Ministry of Environment and Forestry (KLHK) of the Banyumas Regency in 2019 and validated in 2023.Livestock water requirement indicates the volume of water used for the breeding of livestock animals.The water requirement was determined by multiplying the quantity of livestock with the standard rate of consumption per head.Livestock animals were divided into four categories, namely cattle/buffalo, sheep/goats, pigs, and poultry.The calculation formula for livestock water requirements in Equation (4) is based on SNI 6728:1:2015.
19e standard water requirement for irrigated land, according to SNI 6728.1:2015, is 1 liter per second per hectare per day.Irrigation in agriculture is carried out for 120 days (approximately 4 months), which is an assumption for a single planting season.The irrigation water requirement calculation employs the formula specified in SNI19-6728.1-2002 and is presented in equation (3). = 365 × [( × ) + ( × ) + ( × ) + ( × )]

Table 3 .
Water Requirements for Livestock Farming in the Logawa Sub-Watershed in 2022

Table 4 .
Availability and Demand of Surface Water Balance in the Logawa Sub-Watershed in 2022