Agro Bali : Agricultural Journal e-ISSN 2655-853X Vol. 4 No. 1: 72-86, March 2021 DOI: 10.37637/ab.v4i1.688
Study of The Carrying Capacity of The Environment Case Study: The Simanindo Area, Samosir Regency, North Sumatra
Diki Surya Irawan, Deffi Ayu Puspito Sari, Rr. Alifianatifa Anandya Putriahalya Environmental Engineering, Faculty of Engineering and Computer Science, University of Bakrie Corresponding author email: [email protected]
Abstract. Lake Toba area has been designated a National Strategic Area, which is a priority spatial planning area. The Simanindo Area is a sub-district in Samosir Regency which is an island in the middle of Lake Toba, North Sumatra, Indonesia. Lake Toba's current condition has been polluted by organic contamination and high free chlorine. In addition, the existence of fish farming activities or floating net cages that contribute to the contamination of phosphorus by 0.78 mg/l and free chlorine by 0.84 mg/l into Lake Toba which resulted in the need for studies on the carrying capacity and environmental capacity. Land carrying capacity can be calculated by comparing the availability of land with land requirements. While the carrying capacity of water can be calculated by comparing the availability of water with water requirements or using the Thornwaite Mather Water Balance method. Land Capacity can be calculated by the Land Endurance Unit. While the Capacity of Waters can be calculated by STORET analysis or calculation of domestic waste pollution load. The existence of a massive development plan for Simanindo area and rapid population growth is projected to cause the Land Support Capacity of the Simanindo Priority Zone to be conditionally safe in 2040. Water Carrying Capacity experienced a deficit in the atmosphere in July after being calculated with the Thornwaite Mather Water Balance. In addition, the Capacity of Water Bodies is also in the Status of Severe Pollution according to the STORET Method. Keywords: carrying capacity, free chlorine, Lake Toba, phosphorus, Simanindo INTRODUCTION increasing population and the increasing needs Simanindo is a sub-district in Samosir of the shelter (Sari et al., 2018). The use of land Regency which is an island in the middle of Lake and water that does not consider the ecosystem Toba, North Sumatra, Indonesia. The capital of structure will tend to cause an imbalance in the this sub-district is in the village of Ambarita. environment. Simanindo sub-district has a strategic plan According to research by the (Kementrian focused on development in the tourism sector, Kelautan dan Perikanan, 2018) there is a fairly with an object Simanindo tourism, which has a high load of phosphorus entering the body of panoramic view of beauty and the abundance of Lake Toba, namely 941 tons/year from floating objects ancient relics of antiquity (Sihombing et net cage fish culture and 25,334 tons/year al., 2014). The plan to develop the Lake Toba originating from the river that empties into the area as world-class tourism was conveyed by the lake. As well as the phosphorus concentration of President of the Republic of Indonesia. The Lake 0,78 mg / l and free chlorine 0,84 mg / l, where Toba area has been designated as a National it showed that the concentration of phosphorus Strategic Area (Ditjen Bangda, 2020). That and free chlorine in the waters of Lake Toba policy will increase the number of inhabitants exceed the quality standards (Kartamihardja et which can lead to the conversion of land from al., 2015). Based on these data, the water quality empty or agricultural land to a tourism area. This of Lake Toba has decreased, so it is necessary to situation has resulted in increased population study the carrying capacity of the environment in pressure on land, which might be experiencing the Lake Toba area. environmental pressures well beyond its current The country's urban areas are experiencing carrying capacity in the country’s urban area environmental pressures well beyond their (Meilasari-Sugiana et al., 2018). People tend to current carrying capacity (Meilasari-Sugiana et use the remaining space along with the al., 2018). Environmental Supporting Capacity is
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Agro Bali : Agricultural Journal e-ISSN 2655-853X Vol. 4 No. 1: 72-86, March 2021 DOI: 10.37637/ab.v4i1.688 the ability of the environment to support the lives literature studies and related institutions, some of humans, other living things, and the balance of the data used in this study are land cover data, between the two. Meanwhile, the purpose of the total population, the data urban facilities, interaction is to achieve a balance between rainfall data, and test results of water quality of availability and need. Environmental Capacity is Lake Toba in the form of BOD, fecal coli, the ability of the environment to absorb phosphorus, and chlorine-free. This study uses substances, energy, and/or other components evaluation of the carrying capacity of the that enter or are incorporated into it. Meanwhile, environment aims to determine the status of the the purpose of the interaction is the ability of carrying capacity of the land and waters of the nature and the environment to accommodate or Simanindo area, whether or not it has been neutralize waste or excess from an activity exceeded. The stages of determining the without reducing the ability of nature (KLHK, carrying capacity of the environment include 2019). The study of the carrying capacity of the determining the status of a surplus or deficit in environmental in Simanindo area become more the Simanindo area of Lake Toba resulting from important because there are no any study an evaluation of the carrying capacity of the regarding it, therefore this study is expected to environment. The research method used is be an instrument that has an optimal function in descriptive quantitative, namely determining the the context of the management and utilization of status of the carrying capacity based on the natural resources and the environment especially calculation results. in the context of environment control 1. Population Projections instruments process. In calculating the carrying capacity of the environment, one of the most influencing factors METHODS is the population projection. The population This research is structured based on projections of the Simanindo area are divided problem identification that leads to research on into 2 types, namely natural projections and more focused problem topics. This research was progressive projections. Natural projection is a conducted in Simanindo Subdistrict and natural population growth projection that has Laboratory of Environmental Service, Samosir not been influenced by external factors that will Regency, North Sumatra. From December 2019 affect population development in the area. to February 2020. Identification of the problems Natural population projection can be carried found becomes a framework for thinking to find out by observing the growth rate of the solutions. The main stage in this research is to population in the past, so the statistical method identify the characteristics of the area which is is the best method to estimate the population in then evaluated for carrying capacity and the future. This study use 10 year data determining the status of carrying capacity. population in the past to determine the growth rate. Several methods can be used to analyze the In the survey and observation phase, it development of natural population, such as: involves collecting primary and secondary data. 1. Least Square Method This study uses primary data obtained from This method is carried out if the amount direct sampling to the field from several points of data is odd, using the following of the lake scattered in the Simanindo area then equation: checked in the Samosir Environmental Agency laboratory, for secondary data obtained from
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Agro Bali : Agricultural Journal e-ISSN 2655-853X Vol. 4 No. 1: 72-86, March 2021 DOI: 10.37637/ab.v4i1.688
y = a+b x ● yn = Total population ( t ) in the final data y a= i ● x = The period n between the projection year and the yu b= ii data year-end 2 u i …….. (1) ● r = Population growth rate Informations: ● n = Amount of data ● yi = Total population in the 4. Linear Regression Method year i This method is done using the following ● ui = Multiplier variable equation: ● x = he period of year y = a+bx 2 between the projection year and the yx-x(xy) a= 2 2 current year Nx-x ● ui = 0 N(xy)-xy b= 2. Arithmetic Method 2 2 Nx-x …….. (4) This method is used if periodic data
shows the number of additions that are 5. Exponential Method relatively the same each year. The This method is done using the following formula for this method is: equation: y= y+g.xn bx (t) …….. (2) y = a e n Informations: 1 ln a=ln y -b x ● yn = Total population N N x ln y-x ln y in the final data b= 2 2 ● x = The period N x-x …….. (5) between the projection year and the
data year-end 6. Logarithmic Method ● g = verage annual 푦 − 푦 This method is done using the following population growth = 푒푛푑 푓푖푟푠푡 푇표푡푎푙 퐷푎푡푎 equation: 3. Geometric Method y = a+b lnx 1 This method is used if the population a=y -b ln x N data shows a rapid increase from year to N y ln x -y ln x b= year. The formula for this method is: 22 N ln x-ln x x …….. (6) y= y (1+r ) (t) n 1 To determine the most appropriate method yn n r =-1 to be used in planning, it is necessary to calculate yo …….. (3) the correction factor, standard deviation, and the
state of the city's future developments. The Informations: correlation coefficient and standard deviation are ● y(t) = Projected population in obtained from the analysis and calculation of a given year existing population data with population data from the calculation of the projection method
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Agro Bali : Agricultural Journal e-ISSN 2655-853X Vol. 4 No. 1: 72-86, March 2021 DOI: 10.37637/ab.v4i1.688 used. The correlation, r, can be calculated using method. In general, the function of a city the formula: shows the population growth in the 2 SSE future. R=1- SST Meanwhile, the progressive projection is a 2 population projection that sees population 2 P-Pn R=1- 2 development if population migration which is P-P n r …….. (7) expected to support the Simanindo area as an Informations: international class tourism area occurs. The 2 ● R = correlation factor calculations carried out are based on the ideal ● Pn = t otal population in the n year storage capacity, namely preserving the ● Pr = average number of population protected zone areas and optimally utilizing the from known data cultivation zone areas according to the potential ● P = Projected population-based on and limitations of each area for spatial use in the regression calculations method Simanindo area. performed 2. Land Carrying Capacity The correlation criteria are as follows: The land carrying capacity is the ratio 1. r < 0, strong correlation, but negative and between the availability of land and land the relationship between the two requirement or demand and supply side. Land variables is inversely proportional. requirements are obtained by processing the data 2. r = 0, both data have no relationship. needs of residential land and land needs of the 3. r > 1, strong correlation, positive value, economy (KLHK, 2019) and the relationship between the two Land Requirements (ha) = Land variables is straight. Requirements for Settlements (ha) + Land The standard deviation can be calculated Requirements for Economic Activities (ha) using the formula: …….. (9) 1 Calculation of land requirements for 2 2 2 P-Pn settlement is obtained by the formula: P-P-n n ℎ푎 STD = Need for residential land (ha) = 0,005 X n 푝푒표푝푙푒 Total population (people) …….. (8) Calculation of land requirements for economic activity is obtained by the formula: Informations: Land Requirements for Economic Activities ● STD = Standard deviation of (ha) = Number of population (people) X known data (Land requirement per capita for activities ● n = Amount of known data A+B+etc...) …….. (10) Meanwhile, land availability can be
calculated based on the area of land available in The projection method chosen is the the area reduced by the area of protected areas. method with the lowest standard Land Availability (ha) = Total Area (ha) - deviation value and the largest Protected Area (ha) …….. (11) correlation coefficient. The pattern of After obtaining data on land availability and urban development by the function of needs, a comparison is made to determine the the city in the future is also used as a status of the land carrying capacity. reference in determining the projection ● >2 is included in the Safe category;
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Agro Bali : Agricultural Journal e-ISSN 2655-853X Vol. 4 No. 1: 72-86, March 2021 DOI: 10.37637/ab.v4i1.688
● 1 - 2 are included in the conditional safe which areas are in a condition that can still be category; utilized. ● < 1 is included in the unsafe category Analysis of land carrying capacity can be (carrying capacity has been exceeded). seen from the types of Land Capability Units 3. Water Carrying Capacity (SKL) (Kementerian Pekerjaan Umum, 2007) in Water Carrying Capacity, is the ratio the planning area, including: between the amount of availability and the need 1. Land Capability Unit Morphology for water. Water availability is obtained by (Landscape) calculating land runoff, a land-use area, and 2. Land Capability Unit Easiness to do average annual rainfall (Departemen-Kehutanan, 3. Land Capability Unit Slope Stability 2013). Water carrying capacity is the ability of 4. Land Capability Unit Foundation water resources to meet a need by considering its Stability size availability of water. The water carrying 5. Land Capability Unit Water Availability capacity is calculated based on the calculation of 6. Land Capability Unit Natural Disasters water needs and water availability. These 7. Land Capability Unit Drainage variables are compared so that it can be seen that 8. Land Capability Unit Erosion the available water is sufficient for various needs 9. Land Capability Unit Waste Disposal (Santoso, 2015). The calculation of water Classification of land capability for availability can use the runoff coefficient method Simanindo area did by way of seeing each unit which is modified from the rational method, such of land which has been acquired ability (level of as: land capability on every SKL) and compared C = 훴(Ci x Ai) / 훴Ai with the criteria of land capability. R = 훴Ri / m ● Value 0-5, then the status of Low Land SA = 10 x C x R x A …….. (12) Capacity or Zone E; ● Value 6-15, then the status of Less Land Informations: Capacity or Zone D; ● SA = Availability of water (m3/year) ● Value 16-25, then the status of Medium ● C = Weighted runoff coefficient Land Capacity or zone C; ● Ci = i land use runoff coefficient ● Value 26-35, then the status of Sufficient ● Ai = Area of land-use i (ha) Land Capacity or Zone B ● R = Average annual rainfall of the region ● Value 26-45, then the status of High Land (mm/yearly) Capacity or Zone A. ● Ri = Annual rainfall at station i Meanwhile, water needs are calculated as ● M = Number of rainfall observation follows: stations Water Needs = Domestic Water Needs + ● A = Area (ha) Non-Domestic Water Needs ● 10 = conversion factor from mm.ha to m3 Where domestic water demand is calculated based on the following formula: 4. Land Retention Capacity Domestic Water Need = Total Population x The rapid and massive population growth is Water Needs per Capita very much related to land capacity. The value Domestic water demand is a necessity of obtained from the calculation of the carrying water used for daily necessities is 100 capacity can be used as a reference to find out
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Agro Bali : Agricultural Journal e-ISSN 2655-853X Vol. 4 No. 1: 72-86, March 2021 DOI: 10.37637/ab.v4i1.688 liters/person/day. Meanwhile, non-domestic ● PE = corrected potential water demand is obtained by the formula: evapotranspiration (mm/month) Total Non-Domestic Water Needs = Water ● f = correction factor (seen Needs for Industry + Water Needs for Trade in the thickness of the latitude and time and Services + Water Needs for Other correction) Economic Activities 3. Determining the difference in the value The water requirement for each type of of rainfall (P) with corrected potential activity is the multiplication of the number of evapotranspiration (PE), it can be seen units and the water requirement per unit of that the month is included in the wet or activity. After obtaining data on land dry months. availability and needs, a comparison is made to ● (P-PE) > 0, there was a wet determine the status of the land carrying month. capacity. ● (P-PE) < 0, there was a dry ● >2 is included in the Safe category; month. ● 1 - 2 are included in the conditional safe 4. Calculate the accumulated potential category; groundwater loss by: ● < 1 is included in the unsafe category ● In the dry months, or (P
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Agro Bali : Agricultural Journal e-ISSN 2655-853X Vol. 4 No. 1: 72-86, March 2021 DOI: 10.37637/ab.v4i1.688
● Class A: Very Good, score = 0 meets the method that has the largest regression quality standard correlation and the smallest standard deviation. ● Class B : Good, score = -1 s/d -10 lightly But in this projection, the highest regression polluted correlation is generated by the Least Square and ● Class C : Moderate, score = -11 s/d -30 Arithmetic methods, while the lowest standard moderate polluted deviation is owned by the Arithmetic and ● Class D: Poor, score > -31 heavily polluted Exponential e methods. Validity level is more Determination of the water quality status using determined by regression correlation, so the the STORET method is carried out in the projection of the population for the next 20 years following steps: uses the results of using the Arithmetic method. 1. Comparing the measurement result data of However, population projections used in each water parameter with the quality the calculation of capability and capacity standard value by the water class. simanindo environment uses population 2. If the measurement results meet the quality projections calculations progressive contained standard value (measurement results in the Detailed Spatial Plan Draft and Control
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Agro Bali : Agricultural Journal e-ISSN 2655-853X Vol. 4 No. 1: 72-86, March 2021 DOI: 10.37637/ab.v4i1.688 settlements, land requirement for regulation regulating this so as not to exceed the settlement/capita amounted to 50 units/ha, carrying capacity of the land. Spatial planning in assuming a family consists of four people. This the form of policies and rules for the distribution standard has a purpose to utilizing suitable space of areas / zoning for lake utilization is an urgent for a place to live in the area designation of need to be realized immediately. The zoning of settlements in rural areas by providing the lakes based on their utilization in the form of environment which is healthy and safe from protected areas, cultivation areas, fishing areas, natural disasters and can provide environment water transportation areas and tourist areas can that is suitable for community development, make lake management easier and more with still pay attention to the preservation of efficient. (Kristanto et al., 2014) environmental functions. Meanwhile, to calculate the land requirement for existing Table 4. Calculation of the land carrying economic activities, it is done by adding up the capacity for Simanindo areas Land Land Land Carryi land area for several activities, namely tourism, Population Require Availa Years ng Status (people) ments bility commercial, industrial, and public Capaci (ha) (ha) infrastructure. After obtaining data on land ty 2019 17,720 279.41 3135.9 11.22 Safe needs for the economy and housing, these data 2030 53,774 847.93 3135.9 3.70 Safe can be added together to obtain the area of land Condit requirements. The recapitulation of land 2040 101,648 1602.82 3135.9 1.96 ional requirements in the Table 3. Safe Source: Calculation Results (2020)
Table 3. Recapitulation of land requirements in 3. Water Carrying Capacity Simanindo areas To calculate water availability in the Land Requirements Land Year Population Simanindo area, it is necessary to know the Requirements s (people) Economic Resident (ha) (ha) (ha) existing land cover area, and then based on the land cover can be seen the runoff coefficient 2020 17,720 190.81 88.60 279.41 used. The value of C is the total runoff 2030 53,774 579.06 268.87 847.93 2040 101,648 1094.58 508.24 1602.82 coefficient value multiplied by the area of land Source: Calculation Results (2020) cover divided by the total area of land cover . Meanwhile, to find data on land Water availability is the result of multiplying C availability, it is done by reducing the total land with the average rainfall. The calculation of area with the protected area. So that the water availability can use the modified runoff availability of land is obtained 3,135.89 ha. coefficient method from the rational method so Based on data availability and needs that the was that the results are in Table 5. calculated, can be used to search for the carrying Domestic water needs are water needs used capacity of the land, by way of comparison as in for daily needs, namely 100 liters/person/day. Table 4. Domestic water needs can also be obtained by Based on the data above, the following is comparing the number of residents served by the carrying capacity value of the land. Where household connections and public taps are 70:30 the Simanindo area has a status that tends to be because Simanindo District is a rural area with safe in 2020 and 2030 but is conditional safe in an existing population of 17,554 people. 2040 so there is a need for a zoning division Meanwhile, the standard of water consumption in the household connection unit is 100
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Agro Bali : Agricultural Journal e-ISSN 2655-853X Vol. 4 No. 1: 72-86, March 2021 DOI: 10.37637/ab.v4i1.688
L/person/day and for general tap units, it is 30 Simanindo area is 16.20 l / s in 2020, 49.17 l / s L/person/day. Calculation of domestic water in 2030, and 92.94 l / s in 2040. demand can be seen in Table 6 and Table 7. Non-domestic activities in a city usually consist of facilities for education, health, Table 5. Calculation of water availability in worship, commerce, public, recreation and Simanindo areas sports, transportation, and industrial activities Ci SA Are Land (Runoff Ci * (m3/ a C R (Himan et al., 2018) so that projections of non- Cover coefficie Ai year (Ha) nt) ) domestic water demand are obtained as in Table Building 299 0.7 209.3 8. Forest 2054 0.02 41.08 Street 54 0.95 51.3 Pool 83 0.02 1.66 Table 8. Recapitulation of non-domestic water Empty 191 0.2 38.2 17 Land 2.5 28,8 needs 8. 3 66,5 Tahun Yard 1 0.2 0.2 5 Plantation 1230 0.2 246 92 2020 2030 2040 Rice field 389 0.15 58.35 Numb Numb Numbe Facilities Water Shurbs 2091 0.07 146.37 er of er of Water r of Water Dema River 0.02 0 Facili Facili Deman Faciliti Demand nd Total 6392 2.53 16,172 ties ties d (L/s) es (L/s) (L/s) Source: Calculation Results (2020) (Unit) (Unit) (Unit)
Education 37 147,6 316,80 76 126 532,800 00 0 Table 6. Calculation of total population served
Health 80 56,69 by HC and PT 143 78,870 214 102,670 0 Criteria % 2020 % 2030 % 2040
Religion 64 130,0 179,00 Populat 81 101 238,000 00 0 ion 17,720 53,774 101,648
Househ Commerce 27 old 7,430 213 75,120 448 152,170
Connec 70 70 70 General 12,404 37,642 71,154 tion recreation 42 720,0 1,111, 1,307,70 52 57 Served and sports 00 800 0 Public
Taps 30 30 30 Industry 0 5,316 16,132 30,494 - 8 80,000 18 180,000 Served Transporta 0 3,750, 5,625,00 Source: Calculation Results (2020) tion - 2 3 000 0 10617 55915 8138340 L/d L/d L/d 20.00 90.00 .00 Table 7. Calculation of domestic Total Wate L/s 12.29 L/s 64.72 L/s 94.19 2020 2030 2040 r Source: Calculation Results (2020) Dem Conne Wate Wate Wate and ction Popul r Popul r Popul r Stan Type ation Dem ation Dem ation Dem dard (peopl and (peopl and (peopl and Based on the calculation of domestic and (l/p/d e) (l/da e) (l/da e) (l/da ay) y) y) y) non-domestic water needs, the amount of clean House hold 12,40 1,240 37,64 3,764 71,15 7,115 water demand in the Simanindo area can be 100 Conne 4 ,400 2 ,180 4 ,360 ction calculated as shown in Table 9. Public 159,4 16,13 483,9 30,49 914,8 30 5,316 Taps 80 2 66 4 32 Based on the calculated availability and
17,72 1,399 53,77 4,248 101,6 8,030 demand data, it can be used to find the carrying Total 0 ,880 4 ,146 48 ,192 capacity of water, namely by comparing it as in l/s 16.20 l/s 49.17 l/s 92.94 Table 10. Source: Calculation Results (2020)
Based on the above calculations, it can be seen that the domestic water demand in the
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Agro Bali : Agricultural Journal e-ISSN 2655-853X Vol. 4 No. 1: 72-86, March 2021 DOI: 10.37637/ab.v4i1.688
Table 9. Recapitulation of clean water Needs in Thornthwaite Mather method is a method based Simanindo areas on the concept of water balance. This method is Demand 2020 2030 2040 a calculation of water availability based on Domestic (L/s) 16.20 49.17 92.94 Nondomestic (L/s) 12.29 64.72 94.19 existing climatological and hydrological data, Total I 28.49 113.89 187.14 namely rainfall and temperature as an input. The Keperluan Umum Kota results of water balance calculations using the Fire Hydrant (10%) (L/s) 2.85 11.39 18.71 Urban Planning (5%) (L/s) 1.42 5.69 9.36 Thornthwaite method can be seen in Table 11. Total II 32.76 130.97 215.21 Water Loss Rate (%) 17.5 17.5 17.5 Based on the table and Figure 1, it can be Water Loss (L/s) 5.73 22.92 37.66 concluded that the availability of water for one Total Water Produced (L/s) 38.50 153.89 252.87 year has the potential for the use of rainfall with Maximum Daily Discharge 46.20 184.67 303.44 (fm=1.2) the construction of reservoirs. When there is a Peak Hour Discharge (fp=1.8) 69.30 277.00 455.16 (L/s) deficit in July, the government needs to Source: Calculation Results (2020) anticipate water shortages during this July by utilizing Lake Toba as a source of raw water Table 10. Analysis of the water carrying from the Water Treatment Plant in the capacity of Simanindo areas Simanindo area. Year S/D Status Table 11. Thornthwaite method water balance 2019 1711,91 Safe in Simanindo areas Kete 2030 428,27 Safe Bul Pe AP T I a f PE P ΔS rang an x WL 2040 260,63 Safe an 6. 0. 1. 17. 52. 54. 58. surpl 1 9 3 0 4.41 Source: Calculation Results (2020) 96 44 54 95 us 3 6 4 7. 0. 0. 18. 51. 48. 73. 25.5 surpl Based on the analysis of water availability 2 2 3 9 42 33 25 82 7 us 0 6 4 and demand that has been calculated, it is found 7. 0. 1. 18. 50. 52. 84. 32.5 surpl 3 4 3 0 88 25 26 82 6 us that the water carrying capacity in the 8 5 4 7. 0. 1. 19. 49. 49. 107 57.8 surpl 4 7 3 0 36 14 64 .51 7 us Simanindo area is still safe until 2040. However, 6 5 1 7. 0. 1. 19. 48. 50. 96. 45.7 surpl it should be noted that this safe status is the 5 9 3 0 66 47 89 6 1 us 5 5 5 7. 0. 1. result of water carrying capacity if the water 19. 49. 50. 66. 15.9 surpl 6 5 3 0 00 97 97 87 0 us source is taken from Lake Toba. However, to 5 5 2 7. 0. 1. - - 18. 51. 54. 41. defisi 7 0 3 0 12.8 12.8 20 86 45 61 t ensure the availability of water in the Simanindo 7 6 5 4 4 7. 0. 1. 18. 51. 53. 68. 14.3 surpl 8 0 3 0 area is still sufficient for the needs of a decent 18 91 98 36 8 us 6 6 4 8. 0. 1. living for the population, it is necessary to carry 20. 46. 47. 80. 32.8 surpl 9 4 3 0 40 83 30 19 9 us 1 4 1 out strategic studies, especially in the drinking 7. 0. 1. 18. 51. 53. 97. 44.1 surpl 10 1 3 0 26 72 78 88 0 us water supply system plan that is adjusted to the 1 6 4 7. 0. 1. 18. 50. 50. 124 74.0 surpl 11 4 3 0 calculation of Simanindo area Water Demands, 84 34 85 .91 6 us 5 5 1 7. 0. 1. 18. 51. 53. 122 69.1 surpl several things that need to be done are: 12 2 3 0 46 24 29 .44 5 us 1. Need a specific studies related to the plan for 2 6 4 Source: Calculation Results (2020) the dam or reservoir as a future water source Informations : on the island of Samosir to meet the demands T = Temperature (oC) of the Simanindo area. I = The number of heat index in a year 2. The water distribution system is attempted to a = Heat index use a gravity system and avoids the pumping PEx = Potential evapotranspiration system. (mm/month) Concerning the water carrying capacity can F = Latitude and time correlation factor also use the Thornthwaite Mather Method. The
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PE = Corrected potential areas have sufficient land capacity status or evapotranspiration (mm/month) Zone B with a total score of 29. P = Rainfall (mm/month) ΔS = Water balance Table 12. Scores of land capacity analysis Score Informations Protecte Cultivation d Area Area Land Capability Unit 1 Morphology (Landscape) Land Capability Unit 1 4 Easiness to do Land Capability Unit 1 4 Slope Stability Land Capability Unit 1 4 Foundation Stability Land Capability Unit 1 4 Figure 1. Thornthwaite Water Balance Chart Water Availability Land Capability Unit 5 2 Drainage Land Capability Unit 4. Land Retention Capacity 1 4 Erosion This analysis of land capacity is prepared Land Capability Unit 1 4 based on the type of Land Capability Unit Waste Disposal Land Capability Unit 5 2 (Satuan Kemampuan Lahan) in the planning Natural Disaster area, including: Total 17 29 Medium Sufficient 1. Land Capability Unit Morphology Land Status Land Capacity Capacity (Landscape) (Zone B) (Zone C) 2. Land Capability Unit Easiness to do Source: Calculation Results (2020) 3. Land Capability Unit Slope Stability 4. Land Capability Unit Foundation 5. Water Retention Capacity Stability Lake Toba water quality data presented is 5. Land Capability Unit Water Availability the value of each parameter taken from several 6. Land Capability Unit Natural Disasters sampling points. The sampling point used is the 7. Land Capability Unit Drainage sampling point commonly used by the Samosir 8. Land Capability Unit Erosion Regency Environmental Agency to check how 9. Land Capability Unit Waste Disposal the water quality conditions in Samosir. The Classification ability of the land to Priority sampling points are listed in Table 13. and Regions Simanindo did by way of seeing each Figure 2. unit of land which has been acquired ability After taking water samples, the water (level of land capability on every LCU) and samples were given to the Laboratory of the compared with the criteria of land capability. So Environmental Service of Samosir Regency to that the scores obtained from the 9 LCU are do the test water pollution parameters. As for shown in Table 12. these parameters, namely, BOD, Free Chlorine, Based on the table 12, the Simanindo area Phosphate, and Fecal Coli. After obtaining the can be divided into 2 areas, namely protected water quality data that has been tested, the water areas and cultivation areas. Protected areas have carrying capacity is calculated. Calculation of moderate land holding capacity status or Zone C water capacity can be done with STORET with a total score of 17. Meanwhile, cultivated Analysis. According to the Minister of
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Agro Bali : Agricultural Journal e-ISSN 2655-853X Vol. 4 No. 1: 72-86, March 2021 DOI: 10.37637/ab.v4i1.688
Environment Decree No. 115 of 2003, the health of residents because it can lead to STORET method is a method for determining diarrhea and other diseases. The high value of the status of water quality. Water quality is free chlorine can be caused by disinfectants that assessed based on the STORET system are disposed of directly into water bodies such provisions issued by the EPA. Based on the as disinfectants, etc. The high value of free STORET test results, it was found that the value chlorine can disrupt the aquatic ecosystem and of turbidity, free chlorine, phosphate, COD, and the survival of the biota in it. The increase in fecal coli exceeded the quality standard. The phosphate compounds is influenced by nutrient comparison between standard and test result in intake from the catchment, activity residents Table 14. around the lake and fishing activities (Suharto et al., 2016). The high value of this phosphorus can Table 13. Water sampling location result in algae blooming or the massive growth Coordinate of algae and other aquatic biotas which can No. Location North East disrupt the balance of the aquatic ecosystem. Aquafarm The conditions of high phosphorus in waters or 1 Pangambat 2°38'31.94" 98°52'16.63" lakes are also found in Lake Sentani, the Beach Sumber Sari phosphate concentration tends to rise with 2 2°39'15.29" 98°51'38.79" Port decreased rainfall in May and July as well Silintong 3 2°40'17.68" 98°51'43.40" continues to decline from September to January Hotel Beach 4 Siallagan Port 2°40'49.95" 98°50'13.75" when the rainfall is high. Phosphate surge in the Vannessa floating net cage zone on the moon September 5 2°42'26.92" 98°48'41.13" Hotel Beach shows that the rainfall is high and supported by Simanindo 6 2°45'14.97" 98°44'44.81" Ferry Port the decomposition that occurs in the sediment Simarmata increases the concentration of phosphate 7 2°44'17.61" 98°42'5.69" Beach (Indrayani et al., 2015). Source: Survey Results (2020) Based on Environmental Protection Agency
(Keputusan Menteri Negara Lingkungan Hidup, The high value of this turbidity can be 2003) the results of the STORET analysis show caused by the presence of sediment and erosion, that Lake Toba in Simanindo areas indicate that high discharge of domestic waste, agricultural the water quality of Lake Toba has been activities, etc. This high turbidity will result in polluted, by category Class D: Heavily reduced light intensity entering the water, thus Polluted. This condition is almost the same with inhibiting the growth of flora and fauna in the the results of the calculation of the water quality water. The high COD value can be caused by the status of Lake Sentani for each location presence of waste from the domestic activities indicates that Lake Sentani has been moderately of the surrounding community which contains and heavily polluted. The high and low water non-biodegradable chemicals that are directly quality scores are influenced by several disposed of into the lake, which can be derived community activities upstream and downstream from food scraps, or emulsifying oil. This high of the river which empties into the waters of COD value can result in a decrease in oxygen Lake Sentani. Activities that are dominant, content in these waters which will disrupt the among others, settlement, agriculture, C lake ecosystem. The high value of fecal coli can excavation mining, fishing, industry, erosion be caused by the presence of domestic waste that and natural factors of soil content around the enters water bodies. This can endanger the
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Agro Bali : Agricultural Journal e-ISSN 2655-853X Vol. 4 No. 1: 72-86, March 2021 DOI: 10.37637/ab.v4i1.688 lake (Walukow, 2010). Different results were quality standard, in some areas such as Lake obtained in the results of the STORET analysis Tondano, local government try to minimize the in the Riam Kanan dam which produced class B impact of pollution wastewater in Lake lightly polluted, namely water that can be used Tondano, then planned installation development for freshwater fish farming, water farming to waste water management (IPAL) (Mende et al., irrigate plants and / or other uses that require the 2015). Or it can also use simple technology such same water quality as this use (Rahayu, A., as latrines (jamban), the way to overcome the Rahman, A., & Dharmadji, 2017). decline in water quality of the Kuin River due to the presence of fecal coliform bacteria can be done by making special latrines for tidal areas (Santy et al., 2017).
Table 15. Calculation of domestic waste contamination load Demand 2020 2030 2040 Clean Water 46,20 184,67 303,44 Discharge (l/s) Wastewater Discharge 36,96 147,73 242,75 (fab=0.8)(l/s) Average 2,09 2,75 2,39 Figure 2. Map of water sampling location Discharge (m/s) Equivalent Table 14. STORET Highest parameters result Population 17,72 53,77 101,65 Stan Test Result No Parameters Unit Score (/1000 people) dard (maks) Q Min (l/s) 13,14 65,56 122,35 Physics Infiltration 1 Turbidity NTU 5 5.39 -2 Discharge (fi = 7,39 29,55 48,55 Free 2 mg/L 0.03 0.84 Chlorine -16 0.2) (l/s) Channel 3 Phospat mg/L 0.2 0.7824 -4 Infiltration 0,01 0,03 0,05 4 COD mg/L 25 26.83 -4 Discharge Biology Maximum jml/10 5 Fecal coli 100 210 Daily 0 mL -6 2,50 3,30 2,87 Discharge Jumlah -32 (fm=1.2)(l/s) Source: Analysis Results (2020) (Pemerintah Indonesia, Q Max (l/s) 124,79 399,50 577,96 2001) Peak Hour Calculation of domestic waste contaminant Discharge 9,90 32,87 51,46 load in Simanindo area can be seen in Table 15. (fp=1.5)(l/s) Various sources of water pollutants in Lake Source: Calculation Results (2020) Toba include domestic waste, agriculture, livestock, fisheries, water transportation, and CONCLUSION mining of classified minerals. From the discussion above, it can be Based on STORET analysis and domestic concluded that the land carrying capacity in the waste pollution load, it is necessary to handle Simanindo area is still in a safe status in 2020 because the fecal coli content exceeds the and 2030 with a value of availability compared
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Agro Bali : Agricultural Journal e-ISSN 2655-853X Vol. 4 No. 1: 72-86, March 2021 DOI: 10.37637/ab.v4i1.688 to needs of 11.22 and 3.70 and will have h_satu_wisata_super_prioritas_ conditional safe status in 2040 with an Hartanto, P. (2017). Perhitungan Neraca Air Das availability value of 1.96. The water carrying Cidanau Menggunakan Metode Thornthwaite. RISET Geologi Dan capacity in the Simanindo area is still in a safe Pertambangan, 27(2), 213–225. status in 2020, 2030, and 2040. Medium value https://doi.org/10.14203/risetgeotam2017. land retention capacity in protected areas in v27.443 Simanindo areas or zone c.The land retention Himan, M., Syarif, M., & Rahim, M. (2018). capacity in protected areas in Simanindo areas is Analisis Ketersediaan Prasarana Dan of sufficient value or in zone B. Water Retention Sarana Permukiman Nelayan Di Kelurahan Capacity in Simanindo areas using the STORET Lakologou Kecamatan Kokalukuna Kota Baubau. Jurnal Perencanaan Wilayah, method has a heavily polluted quality status. 3(2), 1–15. Water Retention Capacity in Simanindo area has Indrayani, E., Nitimulyo, K. H., Hadisusanto, S., a domestic waste load of 2.5 l/s in 2020, 3.3 l/s & Rustadi, R. (2015). Analisis kandungan in 2030, and 2.87 l/s in 2040. nitrogen, fosfor dan karbon organik di Zoning regulations regarding land use in the Danau Sentani - Papua. Jurnal Manusia Simanindo area are in place so that the status of Dan Lingkungan, 22(2), 217–225. the land carrying capacity is not exceeded. The Kartamihardja, E. S., Fahmi, Z., & Umar, C. (2015). Zonasi Ekosistem Perairan Danau construction of a dam utilizing rainfall to Toba Untuk Pemanfaatan Perikanan anticipate water shortages during July. The use Berkelanjutan. Jurnal Kebijakan Perikanan of Lake Toba as a source of raw water from the Indonesia, 7(1), 1. Clean Water Treatment Plant in the Simanindo https://doi.org/10.15578/jkpi.7.1.2015.1-8 area to anticipate water shortages during July. Kementerian ATR/BPN. (2019). Draft Rencana The handling of domestic wastewater in the Detail Tata Ruang dan Instrumen Lengkap Pengendalian Kawasan Prioritas Simanindo area uses an alternative WWTP or Simanindo. use latrines for tidal areas to reduce the burden Kementerian Pekerjaan Umum. (2007). of water contamination that enters Lake Toba in PEDOMAN TEKNIK ANALISIS ASPEK Simanindo area. FISIK & LINGKUNGAN, EKONOMI SERTA SOSIAL BUDAYA DALAM ACKNOWLEDGMENT PENYUSUNAN RENCANA TATA RUANG (Issue 20). This research is funded by the research grants Kementerian Kelautan dan Perikanan. (2018). from Universitas Bakrie. Daya Dukung dan Zonasi Ekosistem Danau
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