Mechanism of geothermal water level rise induced by pumping in an island

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Water level rise was observed during pumping at a deep geothermal well located approximately 1 km from the western coastline on Seokmo-do Island, Korea. We revealed the mechanism of the water level rise based on the relationship between the water level and tidal efficiency and the relationship between the flowing water temperature and the amount of naturally flowing water to the surface, considering the density and static pressure ( h ) of water. When water was pumped out of the geothermal well over time, the temperature at 9 m depth increased, whereas the density of the water continuously decreased, and then h increased. From the start of the natural flow, the water temperature in the well increased consistently along with a progressive increase in the amount of natural flow. When the temperature of naturally flowing water reaches ~ 65.5℃, the rate of natural flow increases to ~ 1,441 m 3 /d with ∆h of ~ 22.3 m. U sing a simple formula of transmissivity and maximum drawdown during steady-state long-term pumping at a confined aquifer, the water level was 7.03 m above the land surface at a natural flow rate of 1441 m 3 /d. geothermal water tidal efficiency naturally flowing water water-level rise pumping Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 1. Introduction Groundwater level measurement is key to understanding the hydraulic properties and groundwater flow. Excessive pumping can induce groundwater level decline and land subsidence, as in the Su-Xi Change area of China (Zhang et al. 2010 ) and threaten the sustainability of aquifers, as in the case of aquifers in Dhaka, Bangladesh (Hoque et al. 2007 ). In coastal regions, excessive groundwater extraction can cause seawater intrusion, such as in the coastal aquifers of East and Horn, Africa (Idown and Lasisi 2020) and Tripoli city on the Mediterranean coast of Jifarah Plain, Northwest Libya (Alfarrah and Walraevens 2018 ). Groundwater levels in coastal areas can rise due to sea level rise associated with climate change and the greenhouse effect. However, groundwater level rise induced by pumping is rare. The mechanism of the groundwater level rise during pumping has not yet been elucidated. Increases in the groundwater level in unconfined aquifers in coastal regions may lead to inland flooding (Befus et al. 2020 ). In conjunction to sea level rise, the incrementing occurrence of shallow groundwater tables in coastal areas can cause substantial hazards to coastal infrastructure and agricultural activities. Sea-level rise in groundwater levels can also trigger increased roadway fatigue, weakening building structures, reduced sewer and septic drainage, and the potential for mobilizing contaminants in soils above the water table. In other cases, groundwater level rise can occur in conjunction with artificial injection into aquifers to protect against seawater intrusion or to fill groundwater to enhance aquifer storage. We observed an abnormal phenomenon of water level rise during pumping at a deep geothermal well (YG-2) located approximately 1 km from the western coastline of Seokmo-do Island, South Korea (Fig. 1 ). The geothermal well was used to develop a hot-spring bath. This study aimed to reveal the mechanism of water level rise when pumping geothermal water from YG-2 well, based on the temperature and amount of geothermal water, water pressure head, water temperature in the well, and geothermal water density. 2. Geological and hydrogeological setting The study area, Seokmo-do Island, consists of biotite gneiss with a banded structure of leucosomes and melanosomes formed by metamorphic differentiation (Fig. 1 ) (Hwang and Kihm 2005 ). At certain outcrops, the rock has a very thick melanosome layer. Partial melting during metamorphism occurred locally and intruded the biotite gneiss. In the southern part of the island, which is bound by biotite granite, hornblende granodiorite and biotite granite are found in the north and south, respectively. In the southernmost and central-western parts of the island, biotite gneiss is exposed as small outcrops. The rock in the southern part possessed finer grains than that in the northern part. The porphyritic biotite granite (or two-mica granite) in the uppermost-northern part of the island contains a large quantity of biotite with muscovite. The hornblende granodiorite contains plagioclase, quartz, and biotite, with abundant hornblende up to 8 mm in diameter. Hornblende granodiorite displays an elliptical mass with an E-W trend and a mass with an NW-SE trend in Manisan Mountain, which is probably connected underground. Below the alluvium, a WNW-trending strike-slip fault zone exists between the biotite gneiss and biotite granite. The fault zone is believed to be related to geothermal water. To date, 30 geothermal wells have been drilled on Seokmo-do Island (Lee 2018 ; Lee 2017 ; Seong 2013 ), of which, 19 wells were classified into two groups. The group found along the fault zone mostly displays a high discharge temperature and transmissivity, and the group located distantly from the fault zone demonstrates a low discharge temperature and transmissivity (Fig. 2 ). The remaining 11 wells, which are not plotted in Fig. 2 , were buried because of very low temperatures and deficient discharge amounts. The concentration of total solids ranged from 8,940 to 37,400 mg/L, owing to the influence of seawater. The YG-2 geothermal well near the fault zone was drilled about 1,200 m, with an 8 inch diameter from the ground to 960.6 m and a 6.5 inch diameter below that to 1,200 m (Fig. 1 ). An 8 inch diameter casing was installed 120 m from the surface into an open hole deeper than 120 m. The discharge temperatures of the YG-2 well and YG-4 well are 72.4℃ and 25.9℃, respectively. In the YG-2 well, the water level at ~ 9–10 m below the land surface fluctuates around 1 m, along with sea-level oscillation of 4–8 m by the tidal effect. When pumping from YG-2 well, the water level slightly declined at the early stages of pumping and then started to rise, with subsequent natural flow to the surface after several hours of pumping. The relationship of pumping at a well contradicts the water level declining or approaching a constant level over time. 3. Methods Barometric efficiency ( BE ) is the ratio of groundwater level change ( ∆W ) to atmospheric pressure change ( ∆B ) and can be determined using Clark’s ( 1967 ) equation as follows: $$BE=\frac{\sum \varDelta W}{\sum \varDelta B}$$ 1 The groundwater level has an inverse relationship with atmospheric pressure change; that is, an increase in atmospheric pressure generates a decrease in groundwater level. Tidal efficiency ( TE ) is defined as the change in groundwater level in the well due to the change in the ocean tide ( ∆O ) and can be used to estimate the storage coefficient and bulk elastic property in the aquifer. The TE was assumed to be constant when the aquifer was homogeneous and confined with no boundary conditions, ignoring storage in the well. TE can be expressed as follows: $$TE=\frac{\sum \varDelta W}{\sum \varDelta O}$$ 2 4. Results To elucidate the mechanism of the water level rise with pumping from the well, the amount of flowing water and the change in pressure head caused by the tidal effect was compared with the change in the amount of flowing water according to the water density change caused by changes in water temperature. 4.1 Caliper and temperature logs First, calipers and temperature loggings were used to estimate the depth of the aquifer and measure the underground temperature. According to caliper log in the YG-2 well (Fig. 3 ), a fracture zone was detected at a depth of 200 m with a well diameter of 10 inches. Moreover, severe fracture zones were also discovered at an interval of 500–820 m depth, particularly, larger than 12 inches in diameter were found at the depths of around 620 and 820 m. The temperature log in the YG-2 well displayed the bottom temperature of 73.84°C (Fig. 4 ). The geothermal gradient decreases at 820 m depth, maintaining a constant value (~ 48.7°C/km) at depths greater than 820 m. The geothermal gradient indicated that the geothermal water flowing into the well from the fracture zone at 820 m depth rises near the surface. When extending the temperature from the section lower than 820 m to the land surface, the temperature was about 15.73°C, which was similar to the average air temperature in the study area. Therefore, 48.7°C/km is a reasonable representative value of the geothermal gradient in the study area. 4.2 Relationship between groundwater level and tidal efficiency At well YG-2, the natural water level was located between ~ 9 and 10 m below the surface and fluctuated around 1 m due to tidal effects (Fig. 5 ). The geothermal water level reached a maximum of 1.2 m on August 6 during the full moon and a minimum of 50 cm on August 14 during the waning moon. On August 20, at the time of the new moon, the water level reached ~ 1.6 m. Two minimum and maximum levels repeatedly occurred every lunar month. At the end of the monitoring period, the average water level was about 9.0 m, and a water temperature of 16.3°C at depths below 10 m from the water surface, with a slightly decreasing trend over time. In the YG-2 well, the TE value was calculated using the water level and tidal changes in the Oipo-ri area of Namyeon, Ganghwa-gun County. With high tide and ebb tide approximately occurring every 12.42 hours, the sea-level difference between the two tides (∑ ∆O ) and the corresponding water level difference (∑ ∆W ) for August 6 and September 6, 2009, are plotted in Fig. 6 . The results of the regression analysis of these data were as follows: ∑ ∆W = 0.1647 ∑ ∆O – 0.9620 (3) Based on Eq. (3), the TE value is approximately 16.47%. As the sum of TE and BE becomes 1, the BE value should be approximately 83.53%. 4.3 Relationship between the flowing water temperature and the amount of flowing water to the surface When groundwater naturally flows from the bottom of the well to the top, the higher the natural flow amount, the higher the temperature of the flowing water, because a larger flowing water amount with a higher flow velocity results in a smaller temperature loss. That is, the amount of naturally flowing water is positively proportional to the water temperature. In the well, the water temperature is lost to the surrounding rocks when the geothermal water rises from the deep part to the shallow part because the temperature at deeper depths is higher than that at shallow depths. When ~ 193 m 3 /d of geothermal water was pumped out using a ground pump at the YG-2 well, after a decline of approximately 1 m for a short time, the water level gradually increased, and natural flow began approximately 8 h and 40 min after the start of pumping. Throughout natural flow, the flow gradually increased with increasing water temperature. The regression equation of the water temperature ( T ) relative to the natural flow amount ( Q ) is derived based on Fig. 7 : T = 16.32· Q 0.191 (4) The temperature 16.3℃ in Eq. (4) indicates no flow, as shown in Fig. 7 : Table 1 lists the water temperatures relative to natural flow. There was a difference between the measured temperatures and regression values owing to errors in the field measurements and the influence of seawater (Table 1 ). Table 1 Measured and regression temperatures depending on natural flowing amounts Natural flowing amount (m 3 /d) 1054.1 1089.6 1162.7 1297.5 1441.3 Measured temp. (℃) 61.7 61.7 63.8 64.1 65.5 Regression temp. (℃) 61.68 62.07 62.84 64.18 65.48 Error (℃) 0.02 -0.37 0.96 -0.08 0.02 When geothermal water of a certain temperature from a confined aquifer of a certain depth ( D ) continuously flows out of the well (z-direction), the heat continuously propagates laterally from the heat source. In the case study, the well from which natural flow occurs was assumed to be the entire heat source. The differential equation for the temperature distribution by Carslaw and Jaeger (1969) is as follows: $$\frac{{\partial }^{2}T}{\partial {r}^{2}}+\frac{1}{r} \frac{{\partial }^{2}T}{\partial r}+\frac{{\partial }^{2}T}{\partial {z}^{2}}=0$$ 5 Here T is temperature and r is lateral radius. Yuhara and Seno ( 1969 ) established the following relationship between natural flow and water temperature: T = T b ̶ αD + αβQ {1 + exp(- D / βQ )} (6) Here, T is the temperature of flowing water (°C), T b is the temperature (°C) at the bottom of the well, D is well depth (m), Q is the amount of flowing water (L/sec), α is geothermal gradient (°C/m), β corresponds to the proportional coefficient of ρc/(2π r 0 h ˝), with c of specific heat of water, r 0 of well radius, and h ˝ of cooling coefficient. From Eq. ( 5 ), the temperature of the flowing water can be calculated based on the amount of flowing water using the well-bottom temperature, well depth, and geothermal gradient. In Eq. ( 5 ), β and geothermal gradient are intrinsic, unique values of the well and are constant. In reality, the original depth of the flow may be shallower or deeper than the well depth. Therefore, using regression temperature corresponding to the flowing amount (Table 1 ), the proportional coefficient, β , can be calculated by substituting the values shown in Table 2 into Eq. (6). Finally, the theoretical flow temperature T was calculated using Eq. (6). Figure 8 shows the measured and theoretical flow temperature curves according to the amount of flowing water, with good agreement between them. Additionally, the theoretical flowing temperature conforms with the surface temperature (15.73℃). Table 2 The original depth of flow and the temperature of flow at that depth. Geothermal gradient (℃/m), α Original depth of flow (m), T b Temperature of flow at the original depth, T (℃) Proportional coefficient, β 0.04869 1285.2 78.31 161.2 4.4 Density and static pressure of water The density of water was highest at 1 g/mL at 4℃ and gradually decreased with decreasing or increasing temperatures (Fig. 9 ). The density of water is proportional to its molality and pressure. The density of water becomes ~ 4.2% smaller at 100℃ than that at 4℃. When hot geothermal water was mixed with seawater, its molality (0.412 mol) was higher than that of distilled water (Fig. 9 ). Water (0.412 mol) possesses a higher density at 64 bar than at atmospheric pressure. At the YG-2 well, when the original depth of flow was ~ 1,285.2 m the length of the water column was 1,276.2 m, excluding a depth to water of 9 m, and the pressure at the middle depth of the water column was approximately 64 bar. In addition, when the molar concentration of water was approximately 0.412 mol, the equation for the density change was obtained by regression. D = -9.5359·10 − 7 · T w 2 ̶ 6.11·10 -4 · T w + 1.044 (7) Here, D is the density of water and T w is the temperature of the water at the condition of 10℃ ≤ T w ≤ 100℃. The average density of water D avg , which depends on the water temperature along the depth of the well, can be computed by executing the definite integral of Eq. (7), assuming that the water temperature changes linearly with the depth in the well: $${D}_{avg}=\frac{[\int f\left({T}_{w}\right)d{T}_{w}]\genfrac{}{}{0pt}{}{{T}_{b}}{{T}_{9m}}}{{T}_{b}-{T}_{9m}}$$ 8 where T 9m is the water temperature 9 m below the ground, and T b is the water temperature at the well bottom. By inputting 78.31℃ of T b at the original depth of flow (1,285.2 m) and 16.22℃ of T 9m to Eq. ( 8 ), D avg was calculated as 1.0127 g/cm 3 . As shown in Fig. 10 , the water pressure ( P ) at a depth of 1,285.2 m is: P = D avg gh + b (9) where g is gravitational acceleration, h is the height of the water column, and b is atmospheric pressure. Ignoring constant g and b , water pressure at a certain depth, P’ , is: P’ = D avg h (10) By multiplying the average density (1.0127 g/cm 3 ) and the height of the water column (1,276.2 m), the water pressure at a depth of 1,285.2 m for the YG-2 well is calculated to be ~ 1,292.4 m[H2O] D . Accordingly, at water pressure condition of ~ 1,292.4 m[H 2 O] D at 1,285.2 m depth, the height of the water column was calculated with changes in water temperature and density, as shown in Table 3 . Before pumping from the YG-2 well, the water temperature ( T i ) at 1,285.2 m and 9 m depths was ~ 78.31℃ and 16.22℃, respectively, with the height of water column ( h ) of ~ 1,276.2 m. As water was pumped out of the YG-2 well over time, the temperature at 9 m depth increased, the density of the water continuously decreased, and then h increased. Since the start of the natural flow, the water temperature in the well consistently increased with a progressively increasing amount of natural flow. When the temperature of naturally flowing water reaches ~ 65.5℃, the rate of natural flow increased to ~ 1,441 m 3 /d with ∆h of ~ 22.3 m. Table 3 Height of the water column according to the change of water temperature and density. T 9m (℃) T i (℃) D avg (ton/m 3 ) h (m) ∆h (m) 16.2 78.31 1.01268 1276.200 0 20.0 78.31 1.01139 1277.831 1.631 25.0 78.31 1.00967 1280.012 3.812 30.0 78.31 1.00793 1282.221 6.021 35.0 78.31 1.00617 1284.458 8.258 40.0 78.31 1.00440 1286.723 10.523 45.0 78.31 1.00262 1289.016 12.816 50.0 78.31 1.00081 1291.338 15.138 55.0 78.31 0.99899 1293.689 17.489 60.0 78.31 0.99716 1296.070 19.870 65.0 78.31 0.99531 1298.480 22.280 70.0 78.31 0.99344 1300.919 24.719 75.0 78.31 0.99156 1303.389 27.189 4.5 Result of pumping test At the start of the pumping test at the YG-2 well on November 17, 2009, which was performed using a ground pump for several hours, the pumping rate was variable owing to field conditions, with approximately 193 m 3 /d in the early time. After a decline of about 1 m for a short time, the water level gradually rose and natural flowing began to occur at the pumping elapse of 8 hours and 40 minutes on November 18 (Fig. 11 ), with a gradual increase of water temperature and rise in the water level over time. From the start of natural flow, the flow rate gradually increased to about 1,030 ̶ 1,441 m 3 /d, varying with tidal fluctuation between high and low tide (Table 4 ). Siphons can be used to lower the groundwater levels at seepage sites. At this site, natural flow was similar to the siphon effect. In groundwater technology, siphon drainage is effectively applied to reduce groundwater levels (Zhang et al. 2022 ). Both the surface tension and atmospheric pressure with gravity theory advocate a siphon. Gravity and surface tension have different effects according to the well diameter: the smaller the well diameter, the greater the impact of surface tension; the larger the well diameter, the more pronounced the effect of gravity. Therefore, in the case of an 8 inch diameter, the impact of surface tension can be ignored. When the greatest natural flow was approximately 1,441 m 3 /d and the average specific discharge was 204.9 m 2 /d, the drawdown ( s w ) from any point on the surface to the casing was calculated as 7.03 m using the following equation: s w = Q /( ∆Q / ∆s w ) (11) Here Q is the natural flow rate and ∆Q / ∆s w is the specific discharge. By using a simple formula of transmissivity ( Tr ) and s mw of maximum drawdown during steady-state long-term pumping at a confined aquifer (Logan 1964 ) : $$Tr=\frac{1.22Q}{{s}_{mw}}$$ 12 The transmisivity ( Tr ) value of YG-2 well was 250 m 2 /d, with an input Q of 1,441 m 3 /d and s mw of 7.03 m to Eq. ( 12 ). Two days from the start of pumping, the natural flow temperature was maintained at 65.3–65.5℃ with a natural flow rate of about 1,180–1440 m 3 /d. In Table 3 , when the flowing water temperature is about 65℃, ∆h is ~ 22.3 m. Subtracting natural water level of 9 m, ∆h should be about 13.3 m above the casing. This value was higher than 7.03 m at a natural flow rate of 1441 m 3 /d. The difference between the two values may be induced by the friction between the rising water, the well of 6.2 inch diameter below a depth of ~ 960 m, and by resistance due to the sludge at the bottom of the well. Table 4 Specific discharge ( ∆Q / ∆s w ) with tidal fluctuation. Tidal fluctuation, A (cm) Natural flow, Q (m 3 /d) ∆A ·T.E. ( ∆s w , m) ∆Q / ∆s w (m 3 /d/m) 34 1,034.1 1.34 198.4 848 1,300.1 827 1,441.3 1.24 211.6 77 1,180.0 77 1,181.4 1.19 204.6 800 1425.0 Average 204.9 5. Conclusions In this study, we revealed the mechanism of groundwater level rise during the pumping of a deep geothermal well (YG-2) in a coastal area in South Korea. The mechanism was revealed based on the relationship between the temperature and amount of flowing geothermal water, and the water density by calculating the water pressure head. The relationship between the flow amount and change in the water pressure head caused by the tidal effect was also compared. Two days from the beginning of pumping, the natural flow temperature was maintained at 65.3–65.5℃ with a natural flow rate of about 1,180–1440 m. When the flowing water temperature is about 65℃, ∆h is ~ 22.3 m. Subtracting natural water level of 9 m, ∆h should be about 13.3 m above the casing. This value was higher than the actual water level (7.03 m) at a natural flow rate of 1441 m 3 /d. The difference between the two values may be induced by the friction between the rising water, the well of 6.2 inch diameter below a depth of ~ 960 m, and by resistance due to the sludge at the bottom of the well. Hence, in this study, the mechanism of the geothermal water-level rise is explained by the vertical siphon induced by pumping, combined with the density and static pressure of water, and the tidal efficiency. Declarations Acknowledgments: This research was supported by the basic research project of the Korea Institute of Geoscience and Mineral Resources (KIGAM, GP2020-010) funded by the Ministry of Science and ICT, Korea. We express our thanks to Dr. Hak Soo Hwang of Geophysical Research Centre, Songam Co., Ltd. (Daejeon, Republic of Korea) for giving us geophysical idea. References Alfarrah N, Walraevens K (2018) Groundwater overexploitation and seawater intrusion in coastal areas of Arid and Semi-arid Regions. Water 143. doi:10.3390/w10020143 Befus KM, Barnard PL, Hoover DJ, Hart JAF, Voss CI (2020) Increasing threat of coastal groundwater hazards from sea-level rise in California. Nature Climate Change 10:946–952 Carslaw HS, Jaeger JC (1959) Conduction of Heat in Solids. Oxford, New Delhim Clark WE (1967) Computing the barometric efficiency of a well. J Hydraulic Division, American Society of Civil Engineers 93(4):93-98 Hoque MA, Hoque MM, Ahmed KM (2007) Declining groundwater level and aquifer dewatering in Dhaka Metropolitan area, Bangladesh: causes and quantification. Hydrogeology J 15:1523-1534 Hwang JH, Kihm YH (2005) Geological report of the Ganghwa·onsuri sheet. Korea Institute of Geoscience and Mineral Resources p.46 Idowu TE, Lasisi KH (2020) Seawater intrusion in the coastal aquifers of East and Horn of Africa: A review from a regional perspective. Scientific African. https://doi.org/10.1016/j.sciaf.2020.e00402 Lee JT (2018) Hot spring investigation report of Ganghwa Yonggung area. Korea Institute of Geoscience and Mineral Resources p. 128 (in Korean) Lee JT (2017) Hot spring investigation report of Ganghwa Rian area. Korea Institute of Geoscience and Mineral Resources p. 91 (in Korean) Logan J (1964) Estimating Transmissibility from Routine Production Tests of Water Wells. Ground Water 2:35–37 Seong JS (2013) Hot spring investigation report of Ganghwa Haemyeong area. Korea Institute of Geoscience and Mineral Resources p. 76 (in Korean) Yuhara K, Seno K (1969) Geology, geophysics and geochemistry of hot and mineral springs. Chijinshokan & Co., Ltd, Tokyo p.293 (in Japanese) Zhang Y, Xue Y-Q, Wu J-C, Shi X-Q, Yu J (2010) Excessive groundwater withdrawal and resultant land subsidence in the Su-Xi-Chang area, China. Environ Earth Sci 61:1135-1143 Zhang Y, Sun H, Shang Y (2022) Study on Siphon Drainage Capacity of Slopes with Long-Horizontal Pipe Sections. Appl Sci 12(19): 9650 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4421971","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":306412819,"identity":"b6d8412e-b2aa-43e6-aedb-ecdb656725da","order_by":0,"name":"Cholwoo Lee","email":"","orcid":"","institution":"Korea Institute of Geoscience and Mineral Resources (KIGAM)","correspondingAuthor":false,"prefix":"","firstName":"Cholwoo","middleName":"","lastName":"Lee","suffix":""},{"id":306412824,"identity":"81e7d4a7-5d96-45b2-88ca-f9f1043c50d2","order_by":1,"name":"Se-Yeong 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02:11:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4421971/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4421971/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":57190787,"identity":"d7b51b50-046e-485c-ac25-29da9cb04bc7","added_by":"auto","created_at":"2024-05-27 07:14:45","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":952001,"visible":true,"origin":"","legend":"\u003cp\u003eGeological map of the study area.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-4421971/v1/273ae5d88b13b375bf4f0804.png"},{"id":57191249,"identity":"3092dc2c-a401-4c22-a9d5-3a2cab510b96","added_by":"auto","created_at":"2024-05-27 07:22:45","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":139484,"visible":true,"origin":"","legend":"\u003cp\u003eWater temperature distribution of the geothermal wells with the fault zone.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-4421971/v1/b72ae4d29d59e3c851e9e20f.png"},{"id":57191248,"identity":"81c0ed97-9e2f-4c1f-950f-13b49522ed08","added_by":"auto","created_at":"2024-05-27 07:22:45","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":16539,"visible":true,"origin":"","legend":"\u003cp\u003eCaliper log at the well YG-2.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-4421971/v1/36a36059f7501f9530ead25a.png"},{"id":57190786,"identity":"0539b502-9e6d-494b-bfdf-92184acefd76","added_by":"auto","created_at":"2024-05-27 07:14:45","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":21226,"visible":true,"origin":"","legend":"\u003cp\u003eTemperature log at the well YG-2.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-4421971/v1/50dbcaf806bd23bbc925952c.png"},{"id":57190788,"identity":"1f3e0954-031e-4b22-a517-6f0017610534","added_by":"auto","created_at":"2024-05-27 07:14:45","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":39650,"visible":true,"origin":"","legend":"\u003cp\u003eGroundwater level (DTW, m) and temperature from 1 August to 15 October 2009 at the YG-2 well.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-4421971/v1/d7bb4d09cc73a652f86ec6cc.png"},{"id":57190794,"identity":"e258b7ac-d193-49d6-9e84-d1e1c00b41b3","added_by":"auto","created_at":"2024-05-27 07:14:45","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":68182,"visible":true,"origin":"","legend":"\u003cp\u003e∑\u003cem\u003e∆W\u003c/em\u003e vs. ∑\u003cem\u003e∆O \u003c/em\u003efrom 6 August 6 and 6 September 2009 at the YG-2 well.\u003c/p\u003e","description":"","filename":"6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4421971/v1/54f7f4d3691d9fa025518d09.jpg"},{"id":57190791,"identity":"b245506a-2c34-4d14-8e49-81c08035e1f1","added_by":"auto","created_at":"2024-05-27 07:14:45","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":14735,"visible":true,"origin":"","legend":"\u003cp\u003eWater temperature (T) vs. natural flowing amount (Q) at the well YG-2.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-4421971/v1/a82a1f62cb3a33dd49762493.png"},{"id":57191590,"identity":"1e49b429-97fc-46f9-95b4-ff18b9888369","added_by":"auto","created_at":"2024-05-27 07:30:45","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":12722,"visible":true,"origin":"","legend":"\u003cp\u003eMeasured flow temperatures and theoretical temperature curve corresponding to natural flow rates.\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-4421971/v1/7fa74dc70cdcf9f61ecfd8be.png"},{"id":57190796,"identity":"3685c264-179a-4d64-a7ad-e835f9cf2952","added_by":"auto","created_at":"2024-05-27 07:14:46","extension":"jpg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":176440,"visible":true,"origin":"","legend":"\u003cp\u003eDensity vs. water temperature at different molality values and pressures.\u003c/p\u003e","description":"","filename":"9.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4421971/v1/511b6fed1f961a5dceb11bce.jpg"},{"id":57190793,"identity":"02e8df2e-3db8-4764-ab61-930f564cb290","added_by":"auto","created_at":"2024-05-27 07:14:45","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":86809,"visible":true,"origin":"","legend":"\u003cp\u003eScheme of pressure head from the confined aquifer.\u003c/p\u003e","description":"","filename":"floatimage10.png","url":"https://assets-eu.researchsquare.com/files/rs-4421971/v1/20eef9e730000646cc665f7c.png"},{"id":57190795,"identity":"198979ab-6dc0-4a78-a6b4-20281284e74c","added_by":"auto","created_at":"2024-05-27 07:14:45","extension":"jpg","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":138836,"visible":true,"origin":"","legend":"\u003cp\u003ePiezometric head from the surface over time.\u003c/p\u003e","description":"","filename":"11.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4421971/v1/3843e918f196afd97fd7890d.jpg"},{"id":64970225,"identity":"c2afa3cf-0ac3-4553-944c-15aeb1167ff6","added_by":"auto","created_at":"2024-09-21 06:03:28","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2163371,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4421971/v1/2490ad8a-30df-4b13-af8c-f7ac17ea4ce7.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Mechanism of geothermal water level rise induced by pumping in an island","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eGroundwater level measurement is key to understanding the hydraulic properties and groundwater flow. Excessive pumping can induce groundwater level decline and land subsidence, as in the Su-Xi Change area of China (Zhang et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2010\u003c/span\u003e) and threaten the sustainability of aquifers, as in the case of aquifers in Dhaka, Bangladesh (Hoque et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). In coastal regions, excessive groundwater extraction can cause seawater intrusion, such as in the coastal aquifers of East and Horn, Africa (Idown and Lasisi 2020) and Tripoli city on the Mediterranean coast of Jifarah Plain, Northwest Libya (Alfarrah and Walraevens \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eGroundwater levels in coastal areas can rise due to sea level rise associated with climate change and the greenhouse effect. However, groundwater level rise induced by pumping is rare. The mechanism of the groundwater level rise during pumping has not yet been elucidated. Increases in the groundwater level in unconfined aquifers in coastal regions may lead to inland flooding (Befus et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). In conjunction to sea level rise, the incrementing occurrence of shallow groundwater tables in coastal areas can cause substantial hazards to coastal infrastructure and agricultural activities. Sea-level rise in groundwater levels can also trigger increased roadway fatigue, weakening building structures, reduced sewer and septic drainage, and the potential for mobilizing contaminants in soils above the water table. In other cases, groundwater level rise can occur in conjunction with artificial injection into aquifers to protect against seawater intrusion or to fill groundwater to enhance aquifer storage.\u003c/p\u003e \u003cp\u003eWe observed an abnormal phenomenon of water level rise during pumping at a deep geothermal well (YG-2) located approximately 1 km from the western coastline of Seokmo-do Island, South Korea (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The geothermal well was used to develop a hot-spring bath. This study aimed to reveal the mechanism of water level rise when pumping geothermal water from YG-2 well, based on the temperature and amount of geothermal water, water pressure head, water temperature in the well, and geothermal water density.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e"},{"header":"2. Geological and hydrogeological setting","content":"\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eThe study area, Seokmo-do Island, consists of biotite gneiss with a banded structure of leucosomes and melanosomes formed by metamorphic differentiation (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e) (Hwang and Kihm \u003cspan class=\"CitationRef\"\u003e2005\u003c/span\u003e). At certain outcrops, the rock has a very thick melanosome layer. Partial melting during metamorphism occurred locally and intruded the biotite gneiss. In the southern part of the island, which is bound by biotite granite, hornblende granodiorite and biotite granite are found in the north and south, respectively. In the southernmost and central-western parts of the island, biotite gneiss is exposed as small outcrops. The rock in the southern part possessed finer grains than that in the northern part. The porphyritic biotite granite (or two-mica granite) in the uppermost-northern part of the island contains a large quantity of biotite with muscovite. The hornblende granodiorite contains plagioclase, quartz, and biotite, with abundant hornblende up to 8 mm in diameter. Hornblende granodiorite displays an elliptical mass with an E-W trend and a mass with an NW-SE trend in Manisan Mountain, which is probably connected underground. Below the alluvium, a WNW-trending strike-slip fault zone exists between the biotite gneiss and biotite granite. The fault zone is believed to be related to geothermal water.\u003c/p\u003e\n\u003cp\u003eTo date, 30 geothermal wells have been drilled on Seokmo-do Island (Lee \u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e; Lee \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e; Seong \u003cspan class=\"CitationRef\"\u003e2013\u003c/span\u003e), of which, 19 wells were classified into two groups. The group found along the fault zone mostly displays a high discharge temperature and transmissivity, and the group located distantly from the fault zone demonstrates a low discharge temperature and transmissivity (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). The remaining 11 wells, which are not plotted in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e, were buried because of very low temperatures and deficient discharge amounts. The concentration of total solids ranged from 8,940 to 37,400 mg/L, owing to the influence of seawater. The YG-2 geothermal well near the fault zone was drilled about 1,200 m, with an 8 inch diameter from the ground to 960.6 m and a 6.5 inch diameter below that to 1,200 m (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). An 8 inch diameter casing was installed 120 m from the surface into an open hole deeper than 120 m. The discharge temperatures of the YG-2 well and YG-4 well are 72.4℃ and 25.9℃, respectively.\u003c/p\u003e\n\u003cp\u003eIn the YG-2 well, the water level at ~\u0026thinsp;9\u0026ndash;10 m below the land surface fluctuates around 1 m, along with sea-level oscillation of 4\u0026ndash;8 m by the tidal effect. When pumping from YG-2 well, the water level slightly declined at the early stages of pumping and then started to rise, with subsequent natural flow to the surface after several hours of pumping. The relationship of pumping at a well contradicts the water level declining or approaching a constant level over time.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"3. Methods","content":"\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eBarometric efficiency (\u003cem\u003eBE\u003c/em\u003e) is the ratio of groundwater level change (\u003cem\u003e∆W\u003c/em\u003e) to atmospheric pressure change (\u003cem\u003e∆B\u003c/em\u003e) and can be determined using Clark\u0026rsquo;s (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e1967\u003c/span\u003e) equation as follows:\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Equ1\" class=\"Equation\"\u003e \u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$$BE=\\frac{\\sum \\varDelta W}{\\sum \\varDelta B}$$\u003c/div\u003e \u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe groundwater level has an inverse relationship with atmospheric pressure change; that is, an increase in atmospheric pressure generates a decrease in groundwater level.\u003c/p\u003e \u003cp\u003eTidal efficiency (\u003cem\u003eTE\u003c/em\u003e) is defined as the change in groundwater level in the well due to the change in the ocean tide (\u003cem\u003e∆O\u003c/em\u003e) and can be used to estimate the storage coefficient and bulk elastic property in the aquifer. The \u003cem\u003eTE\u003c/em\u003e was assumed to be constant when the aquifer was homogeneous and confined with no boundary conditions, ignoring storage in the well. \u003cem\u003eTE\u003c/em\u003e can be expressed as follows:\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Equ2\" class=\"Equation\"\u003e \u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e\n$$TE=\\frac{\\sum \\varDelta W}{\\sum \\varDelta O}$$\u003c/div\u003e \u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"4. Results","content":"\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eTo elucidate the mechanism of the water level rise with pumping from the well, the amount of flowing water and the change in pressure head caused by the tidal effect was compared with the change in the amount of flowing water according to the water density change caused by changes in water temperature.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n\u003ch2\u003e4.1 Caliper and temperature logs\u003c/h2\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eFirst, calipers and temperature loggings were used to estimate the depth of the aquifer and measure the underground temperature. According to caliper log in the YG-2 well (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e), a fracture zone was detected at a depth of 200 m with a well diameter of 10 inches. Moreover, severe fracture zones were also discovered at an interval of 500\u0026ndash;820 m depth, particularly, larger than 12 inches in diameter were found at the depths of around 620 and 820 m.\u003c/p\u003e\n\u003c/div\u003e\n\u003cp\u003eThe temperature log in the YG-2 well displayed the bottom temperature of 73.84\u0026deg;C (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e). The geothermal gradient decreases at 820 m depth, maintaining a constant value (~\u0026thinsp;48.7\u0026deg;C/km) at depths greater than 820 m. The geothermal gradient indicated that the geothermal water flowing into the well from the fracture zone at 820 m depth rises near the surface. When extending the temperature from the section lower than 820 m to the land surface, the temperature was about 15.73\u0026deg;C, which was similar to the average air temperature in the study area. Therefore, 48.7\u0026deg;C/km is a reasonable representative value of the geothermal gradient in the study area.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n\u003ch2\u003e4.2 Relationship between groundwater level and tidal efficiency\u003c/h2\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eAt well YG-2, the natural water level was located between ~\u0026thinsp;9 and 10 m below the surface and fluctuated around 1 m due to tidal effects (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e). The geothermal water level reached a maximum of 1.2 m on August 6 during the full moon and a minimum of 50 cm on August 14 during the waning moon. On August 20, at the time of the new moon, the water level reached\u0026thinsp;~\u0026thinsp;1.6 m. Two minimum and maximum levels repeatedly occurred every lunar month. At the end of the monitoring period, the average water level was about 9.0 m, and a water temperature of 16.3\u0026deg;C at depths below 10 m from the water surface, with a slightly decreasing trend over time.\u003c/p\u003e\n\u003cp\u003eIn the YG-2 well, the \u003cem\u003eTE\u003c/em\u003e value was calculated using the water level and tidal changes in the Oipo-ri area of Namyeon, Ganghwa-gun County. With high tide and ebb tide approximately occurring every 12.42 hours, the sea-level difference between the two tides (\u0026sum;\u003cem\u003e∆O\u003c/em\u003e) and the corresponding water level difference (\u0026sum;\u003cem\u003e∆W\u003c/em\u003e) for August 6 and September 6, 2009, are plotted in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e. The results of the regression analysis of these data were as follows:\u003c/p\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026sum;\u003cem\u003e∆W\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.1647 \u0026sum;\u003cem\u003e∆O\u003c/em\u003e \u0026ndash; 0.9620 (3)\u003c/p\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eBased on Eq.\u0026nbsp;(3), the \u003cem\u003eTE\u003c/em\u003e value is approximately 16.47%. As the sum of \u003cem\u003eTE\u003c/em\u003e and \u003cem\u003eBE\u003c/em\u003e becomes 1, the \u003cem\u003eBE\u003c/em\u003e value should be approximately 83.53%.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n\u003ch2\u003e4.3 Relationship between the flowing water temperature and the amount of flowing water to the surface\u003c/h2\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eWhen groundwater naturally flows from the bottom of the well to the top, the higher the natural flow amount, the higher the temperature of the flowing water, because a larger flowing water amount with a higher flow velocity results in a smaller temperature loss. That is, the amount of naturally flowing water is positively proportional to the water temperature. In the well, the water temperature is lost to the surrounding rocks when the geothermal water rises from the deep part to the shallow part because the temperature at deeper depths is higher than that at shallow depths.\u003c/p\u003e\n\u003cp\u003eWhen ~\u0026thinsp;193 m\u003csup\u003e3\u003c/sup\u003e/d of geothermal water was pumped out using a ground pump at the YG-2 well, after a decline of approximately 1 m for a short time, the water level gradually increased, and natural flow began approximately 8 h and 40 min after the start of pumping. Throughout natural flow, the flow gradually increased with increasing water temperature. The regression equation of the water temperature (\u003cem\u003eT\u003c/em\u003e) relative to the natural flow amount (\u003cem\u003eQ\u003c/em\u003e) is derived based on Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e:\u003c/p\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cem\u003eT\u003c/em\u003e\u0026thinsp;=\u0026thinsp;16.32\u0026middot;\u003cem\u003eQ\u003c/em\u003e\u003csup\u003e0.191\u003c/sup\u003e (4)\u003c/p\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eThe temperature 16.3℃ in Eq.\u0026nbsp;(4) indicates no flow, as shown in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e: Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e lists the water temperatures relative to natural flow. There was a difference between the measured temperatures and regression values owing to errors in the field measurements and the influence of seawater (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eMeasured and regression temperatures depending on natural flowing amounts\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eNatural flowing amount (m\u003csup\u003e3\u003c/sup\u003e/d)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e1054.1\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e1089.6\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e1162.7\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e1297.5\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e1441.3\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eMeasured temp. (℃)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e61.7\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e61.7\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e63.8\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e64.1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e65.5\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eRegression temp. (℃)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e61.68\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e62.07\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e62.84\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e64.18\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e65.48\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eError (℃)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.02\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e-0.37\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.96\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e-0.08\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.02\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eWhen geothermal water of a certain temperature from a confined aquifer of a certain depth (\u003cem\u003eD\u003c/em\u003e) continuously flows out of the well (z-direction), the heat continuously propagates laterally from the heat source. In the case study, the well from which natural flow occurs was assumed to be the entire heat source. The differential equation for the temperature distribution by Carslaw and Jaeger (1969) is as follows:\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Equ3\" class=\"Equation\"\u003e\n\u003cdiv id=\"FileID_Equ3\" class=\"mathdisplay\"\u003e$$\\frac{{\\partial }^{2}T}{\\partial {r}^{2}}+\\frac{1}{r} \\frac{{\\partial }^{2}T}{\\partial r}+\\frac{{\\partial }^{2}T}{\\partial {z}^{2}}=0$$\u003c/div\u003e\n\u003cdiv class=\"EquationNumber\"\u003e5\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eHere \u003cem\u003eT\u003c/em\u003e is temperature and \u003cem\u003er\u003c/em\u003e is lateral radius.\u003c/p\u003e\n\u003cp\u003eYuhara and Seno (\u003cspan class=\"CitationRef\"\u003e1969\u003c/span\u003e) established the following relationship between natural flow and water temperature:\u003c/p\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cem\u003eT\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003eb\u003c/em\u003e\u003c/sub\u003e ̶ \u003cem\u003e\u0026alpha;D\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003e\u0026alpha;\u0026beta;Q\u003c/em\u003e{1\u0026thinsp;+\u0026thinsp;exp(-\u003cem\u003eD\u003c/em\u003e/\u003cem\u003e\u0026beta;Q\u003c/em\u003e)} (6)\u003c/p\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eHere, \u003cem\u003eT\u003c/em\u003e is the temperature of flowing water (\u0026deg;C), \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003eb\u003c/em\u003e\u003c/sub\u003e is the temperature (\u0026deg;C) at the bottom of the well, \u003cem\u003eD\u003c/em\u003e is well depth (m), \u003cem\u003eQ\u003c/em\u003e is the amount of flowing water (L/sec), \u0026alpha; is geothermal gradient (\u0026deg;C/m), \u003cem\u003e\u0026beta;\u003c/em\u003e corresponds to the proportional coefficient of \u0026rho;c/(2\u0026pi;\u003cem\u003er\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e\u003cem\u003eh\u003c/em\u003e˝), with \u003cem\u003ec\u003c/em\u003e of specific heat of water, \u003cem\u003er\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e of well radius, and \u003cem\u003eh\u003c/em\u003e˝ of cooling coefficient. From Eq.\u0026nbsp;(\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e), the temperature of the flowing water can be calculated based on the amount of flowing water using the well-bottom temperature, well depth, and geothermal gradient. In Eq.\u0026nbsp;(\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e), \u003cem\u003e\u0026beta;\u003c/em\u003e and geothermal gradient are intrinsic, unique values of the well and are constant.\u003c/p\u003e\n\u003cp\u003eIn reality, the original depth of the flow may be shallower or deeper than the well depth. Therefore, using regression temperature corresponding to the flowing amount (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e), the proportional coefficient, \u003cem\u003e\u0026beta;\u003c/em\u003e, can be calculated by substituting the values shown in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e into Eq.\u0026nbsp;(6). Finally, the theoretical flow temperature \u003cem\u003eT\u003c/em\u003e was calculated using Eq.\u0026nbsp;(6). Figure\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e shows the measured and theoretical flow temperature curves according to the amount of flowing water, with good agreement between them. Additionally, the theoretical flowing temperature conforms with the surface temperature (15.73℃).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eThe original depth of flow and the temperature of flow at that depth.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eGeothermal gradient\u003c/p\u003e\n\u003cp\u003e(℃/m), \u0026alpha;\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eOriginal depth of flow (m), \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003eb\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eTemperature of flow\u003c/p\u003e\n\u003cp\u003eat the original depth, \u003cem\u003eT\u003c/em\u003e (℃)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eProportional coefficient, \u003cem\u003e\u0026beta;\u003c/em\u003e\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.04869\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1285.2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e78.31\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e161.2\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n\u003ch2\u003e4.4 Density and static pressure of water\u003c/h2\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eThe density of water was highest at 1 g/mL at 4℃ and gradually decreased with decreasing or increasing temperatures (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e9\u003c/span\u003e). The density of water is proportional to its molality and pressure. The density of water becomes\u0026thinsp;~\u0026thinsp;4.2% smaller at 100℃ than that at 4℃. When hot geothermal water was mixed with seawater, its molality (0.412 mol) was higher than that of distilled water (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e9\u003c/span\u003e). Water (0.412 mol) possesses a higher density at 64 bar than at atmospheric pressure.\u003c/p\u003e\n\u003cp\u003eAt the YG-2 well, when the original depth of flow was ~\u0026thinsp;1,285.2 m the length of the water column was 1,276.2 m, excluding a depth to water of 9 m, and the pressure at the middle depth of the water column was approximately 64 bar. In addition, when the molar concentration of water was approximately 0.412 mol, the equation for the density change was obtained by regression.\u003c/p\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cem\u003eD\u003c/em\u003e = -9.5359\u0026middot;10\u003csup\u003e\u0026minus;\u0026thinsp;7\u003c/sup\u003e\u0026middot;\u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003ew\u003c/em\u003e\u003c/sub\u003e\u003csup\u003e2\u003c/sup\u003e ̶ 6.11\u0026middot;10\u003csup\u003e-4\u003c/sup\u003e\u0026middot;\u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003ew\u003c/em\u003e\u003c/sub\u003e \u003cem\u003e+\u003c/em\u003e 1.044 (7)\u003c/p\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eHere, \u003cem\u003eD\u003c/em\u003e is the density of water and \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003ew\u003c/em\u003e\u003c/sub\u003e is the temperature of the water at the condition of 10℃ \u0026le; \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003ew\u003c/em\u003e\u003c/sub\u003e \u0026le; 100℃. The average density of water \u003cem\u003eD\u003c/em\u003e\u003csub\u003e\u003cem\u003eavg\u003c/em\u003e\u003c/sub\u003e, which depends on the water temperature along the depth of the well, can be computed by executing the definite integral of Eq.\u0026nbsp;(7), assuming that the water temperature changes linearly with the depth in the well:\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Equ4\" class=\"Equation\"\u003e\n\u003cdiv id=\"FileID_Equ4\" class=\"mathdisplay\"\u003e$${D}_{avg}=\\frac{[\\int f\\left({T}_{w}\\right)d{T}_{w}]\\genfrac{}{}{0pt}{}{{T}_{b}}{{T}_{9m}}}{{T}_{b}-{T}_{9m}}$$\u003c/div\u003e\n\u003cdiv class=\"EquationNumber\"\u003e8\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003ewhere \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e9m\u003c/em\u003e\u003c/sub\u003e is the water temperature 9 m below the ground, and \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003eb\u003c/em\u003e\u003c/sub\u003e is the water temperature at the well bottom. By inputting 78.31℃ of \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003eb\u003c/em\u003e\u003c/sub\u003e at the original depth of flow (1,285.2 m) and 16.22℃ of \u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e9m\u003c/em\u003e\u003c/sub\u003e to Eq.\u0026nbsp;(\u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e), \u003cem\u003eD\u003c/em\u003e\u003csub\u003e\u003cem\u003eavg\u003c/em\u003e\u003c/sub\u003e was calculated as 1.0127 g/cm\u003csup\u003e3\u003c/sup\u003e. As shown in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e10\u003c/span\u003e, the water pressure (\u003cem\u003eP\u003c/em\u003e) at a depth of 1,285.2 m is:\u003c/p\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;\u003cem\u003eD\u003c/em\u003e\u003csub\u003e\u003cem\u003eavg\u003c/em\u003e\u003c/sub\u003e \u003cem\u003egh\u003c/em\u003e\u0026thinsp;+\u0026thinsp;\u003cem\u003eb\u003c/em\u003e (9)\u003c/p\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003ewhere \u003cem\u003eg\u003c/em\u003e is gravitational acceleration, \u003cem\u003eh\u003c/em\u003e is the height of the water column, and \u003cem\u003eb\u003c/em\u003e is atmospheric pressure. Ignoring constant \u003cem\u003eg\u003c/em\u003e and \u003cem\u003eb\u003c/em\u003e, water pressure at a certain depth, \u003cem\u003eP\u0026rsquo;\u003c/em\u003e, is:\u003c/p\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cem\u003eP\u0026rsquo;\u003c/em\u003e = \u003cem\u003eD\u003c/em\u003e\u003csub\u003e\u003cem\u003eavg\u003c/em\u003e\u003c/sub\u003e \u003cem\u003eh\u003c/em\u003e (10)\u003c/p\u003e\n\u003cp\u003eBy multiplying the average density (1.0127 g/cm\u003csup\u003e3\u003c/sup\u003e) and the height of the water column (1,276.2 m), the water pressure at a depth of 1,285.2 m for the YG-2 well is calculated to be ~\u0026thinsp;1,292.4 m[H2O]\u003csub\u003e\u003cem\u003eD\u003c/em\u003e\u003c/sub\u003e.\u003c/p\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eAccordingly, at water pressure condition of ~\u0026thinsp;1,292.4 m[H\u003csub\u003e2\u003c/sub\u003eO]\u003csub\u003e\u003cem\u003eD\u003c/em\u003e\u003c/sub\u003e at 1,285.2 m depth, the height of the water column was calculated with changes in water temperature and density, as shown in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e. Before pumping from the YG-2 well, the water temperature (\u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sub\u003e) at 1,285.2 m and 9 m depths was ~\u0026thinsp;78.31℃ and 16.22℃, respectively, with the height of water column (\u003cem\u003eh\u003c/em\u003e) of ~\u0026thinsp;1,276.2 m. As water was pumped out of the YG-2 well over time, the temperature at 9 m depth increased, the density of the water continuously decreased, and then \u003cem\u003eh\u003c/em\u003e increased. Since the start of the natural flow, the water temperature in the well consistently increased with a progressively increasing amount of natural flow. When the temperature of naturally flowing water reaches\u0026thinsp;~\u0026thinsp;65.5℃, the rate of natural flow increased to ~\u0026thinsp;1,441 m\u003csup\u003e3\u003c/sup\u003e/d with \u003cem\u003e∆h\u003c/em\u003e of ~\u0026thinsp;22.3 m.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab3\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eHeight of the water column according to the change of water temperature and density.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003e9m\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e\n\u003cp\u003e(℃)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eT\u003c/em\u003e\u003csub\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e\n\u003cp\u003e(℃)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eD\u003c/em\u003e\u003csub\u003e\u003cem\u003eavg\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e\n\u003cp\u003e(ton/m\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eh\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e(m)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003e∆h\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e(m)\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e16.2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e78.31\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.01268\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1276.200\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e20.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e78.31\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.01139\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1277.831\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.631\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e25.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e78.31\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.00967\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1280.012\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e3.812\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e30.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e78.31\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.00793\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1282.221\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e6.021\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e35.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e78.31\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.00617\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1284.458\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e8.258\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e40.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e78.31\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.00440\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1286.723\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e10.523\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e45.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e78.31\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.00262\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1289.016\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e12.816\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e50.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e78.31\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.00081\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1291.338\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e15.138\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e55.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e78.31\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.99899\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1293.689\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e17.489\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e60.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e78.31\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.99716\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1296.070\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e19.870\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e65.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e78.31\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.99531\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1298.480\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e22.280\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e70.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e78.31\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.99344\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1300.919\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e24.719\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e75.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e78.31\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.99156\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1303.389\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e27.189\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\n\u003ch2\u003e4.5 Result of pumping test\u003c/h2\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eAt the start of the pumping test at the YG-2 well on November 17, 2009, which was performed using a ground pump for several hours, the pumping rate was variable owing to field conditions, with approximately 193 m\u003csup\u003e3\u003c/sup\u003e/d in the early time. After a decline of about 1 m for a short time, the water level gradually rose and natural flowing began to occur at the pumping elapse of 8 hours and 40 minutes on November 18 (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e11\u003c/span\u003e), with a gradual increase of water temperature and rise in the water level over time. From the start of natural flow, the flow rate gradually increased to about 1,030 ̶ 1,441 m\u003csup\u003e3\u003c/sup\u003e/d, varying with tidal fluctuation between high and low tide (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e). Siphons can be used to lower the groundwater levels at seepage sites. At this site, natural flow was similar to the siphon effect. In groundwater technology, siphon drainage is effectively applied to reduce groundwater levels (Zhang et al. \u003cspan class=\"CitationRef\"\u003e2022\u003c/span\u003e). Both the surface tension and atmospheric pressure with gravity theory advocate a siphon. Gravity and surface tension have different effects according to the well diameter: the smaller the well diameter, the greater the impact of surface tension; the larger the well diameter, the more pronounced the effect of gravity. Therefore, in the case of an 8 inch diameter, the impact of surface tension can be ignored.\u003c/p\u003e\n\u003cp\u003eWhen the greatest natural flow was approximately 1,441 m\u003csup\u003e3\u003c/sup\u003e/d and the average specific discharge was 204.9 m\u003csup\u003e2\u003c/sup\u003e/d, the drawdown (\u003cem\u003es\u003c/em\u003e\u003csub\u003e\u003cem\u003ew\u003c/em\u003e\u003c/sub\u003e) from any point on the surface to the casing was calculated as 7.03 m using the following equation:\u003c/p\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cem\u003es\u003c/em\u003e \u003csub\u003e \u003cem\u003ew\u003c/em\u003e \u003c/sub\u003e = \u003cem\u003eQ\u003c/em\u003e/(\u003cem\u003e∆Q\u003c/em\u003e/\u003cem\u003e∆s\u003c/em\u003e\u003csub\u003e\u003cem\u003ew\u003c/em\u003e\u003c/sub\u003e) (11)\u003c/p\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eHere \u003cem\u003eQ\u003c/em\u003e is the natural flow rate and \u003cem\u003e∆Q\u003c/em\u003e/\u003cem\u003e∆s\u003c/em\u003e\u003csub\u003e\u003cem\u003ew\u003c/em\u003e\u003c/sub\u003e is the specific discharge. By using a simple formula of transmissivity (\u003cem\u003eTr\u003c/em\u003e) and \u003cem\u003es\u003c/em\u003e\u003csub\u003e\u003cem\u003emw\u003c/em\u003e\u003c/sub\u003e of maximum drawdown during steady-state long-term pumping at a confined aquifer (Logan \u003cspan class=\"CitationRef\"\u003e1964\u003c/span\u003e) :\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Equ5\" class=\"Equation\"\u003e\n\u003cdiv id=\"FileID_Equ5\" class=\"mathdisplay\"\u003e$$Tr=\\frac{1.22Q}{{s}_{mw}}$$\u003c/div\u003e\n\u003cdiv class=\"EquationNumber\"\u003e12\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eThe transmisivity (\u003cem\u003eTr\u003c/em\u003e) value of YG-2 well was 250 m\u003csup\u003e2\u003c/sup\u003e/d, with an input \u003cem\u003eQ\u003c/em\u003e of 1,441 m\u003csup\u003e3\u003c/sup\u003e/d and \u003cem\u003es\u003c/em\u003e\u003csub\u003e\u003cem\u003emw\u003c/em\u003e\u003c/sub\u003e of 7.03 m to Eq.\u0026nbsp;(\u003cspan class=\"InternalRef\"\u003e12\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eTwo days from the start of pumping, the natural flow temperature was maintained at 65.3\u0026ndash;65.5℃ with a natural flow rate of about 1,180\u0026ndash;1440 m\u003csup\u003e3\u003c/sup\u003e/d. In Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e, when the flowing water temperature is about 65℃, \u003cem\u003e∆h\u003c/em\u003e is ~\u0026thinsp;22.3 m. Subtracting natural water level of 9 m, \u003cem\u003e∆h\u003c/em\u003e should be about 13.3 m above the casing. This value was higher than 7.03 m at a natural flow rate of 1441 m\u003csup\u003e3\u003c/sup\u003e/d. The difference between the two values may be induced by the friction between the rising water, the well of 6.2 inch diameter below a depth of ~\u0026thinsp;960 m, and by resistance due to the sludge at the bottom of the well.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab4\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eSpecific discharge (\u003cem\u003e∆Q\u003c/em\u003e/\u003cem\u003e∆s\u003c/em\u003e\u003csub\u003e\u003cem\u003ew\u003c/em\u003e\u003c/sub\u003e) with tidal fluctuation.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eTidal fluctuation, \u003cem\u003eA\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e(cm)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eNatural flow, \u003cem\u003eQ\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e(m\u003csup\u003e3\u003c/sup\u003e/d)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003e∆A\u003c/em\u003e\u0026middot;T.E.\u003c/p\u003e\n\u003cp\u003e(\u003cem\u003e∆s\u003c/em\u003e\u003csub\u003e\u003cem\u003ew\u003c/em\u003e\u003c/sub\u003e, m)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003e∆Q\u003c/em\u003e/\u003cem\u003e∆s\u003c/em\u003e\u003csub\u003e\u003cem\u003ew\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e\n\u003cp\u003e(m\u003csup\u003e3\u003c/sup\u003e/d/m)\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e34\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1,034.1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e1.34\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e198.4\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e848\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1,300.1\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e827\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1,441.3\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e1.24\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e211.6\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e77\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1,180.0\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e77\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1,181.4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e1.19\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e204.6\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e800\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1425.0\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\" align=\"left\"\u003e\n\u003cp\u003eAverage\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e204.9\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003c/div\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eIn this study, we revealed the mechanism of groundwater level rise during the pumping of a deep geothermal well (YG-2) in a coastal area in South Korea. The mechanism was revealed based on the relationship between the temperature and amount of flowing geothermal water, and the water density by calculating the water pressure head. The relationship between the flow amount and change in the water pressure head caused by the tidal effect was also compared.\u003c/p\u003e \u003cp\u003eTwo days from the beginning of pumping, the natural flow temperature was maintained at 65.3\u0026ndash;65.5℃ with a natural flow rate of about 1,180\u0026ndash;1440 m. When the flowing water temperature is about 65℃, \u003cem\u003e∆h\u003c/em\u003e is ~\u0026thinsp;22.3 m. Subtracting natural water level of 9 m, \u003cem\u003e∆h\u003c/em\u003e should be about 13.3 m above the casing. This value was higher than the actual water level (7.03 m) at a natural flow rate of 1441 m\u003csup\u003e3\u003c/sup\u003e/d. The difference between the two values may be induced by the friction between the rising water, the well of 6.2 inch diameter below a depth of ~\u0026thinsp;960 m, and by resistance due to the sludge at the bottom of the well.\u003c/p\u003e \u003cp\u003eHence, in this study, the mechanism of the geothermal water-level rise is explained by the vertical siphon induced by pumping, combined with the density and static pressure of water, and the tidal efficiency.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAcknowledgments:\u003c/h2\u003e \u003cp\u003eThis research was supported by the basic research project of the Korea Institute of Geoscience and Mineral Resources (KIGAM, GP2020-010) funded by the Ministry of Science and ICT, Korea. We express our thanks to Dr. Hak Soo Hwang of Geophysical Research Centre, Songam Co., Ltd. (Daejeon, Republic of Korea) for giving us geophysical idea.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAlfarrah N, Walraevens K (2018) Groundwater overexploitation and seawater intrusion in coastal areas of Arid and Semi-arid Regions. Water 143. doi:10.3390/w10020143\u003c/li\u003e\n\u003cli\u003eBefus KM, Barnard PL, Hoover DJ, Hart JAF, Voss CI (2020) Increasing threat of coastal groundwater hazards from sea-level rise in California. Nature Climate Change 10:946\u0026ndash;952\u003c/li\u003e\n\u003cli\u003eCarslaw HS, Jaeger JC (1959) Conduction of Heat in Solids. Oxford, New Delhim\u003c/li\u003e\n\u003cli\u003eClark WE (1967) Computing the barometric efficiency of a well. J Hydraulic Division, American Society of Civil Engineers 93(4):93-98\u003c/li\u003e\n\u003cli\u003eHoque MA, Hoque MM, Ahmed KM (2007) Declining groundwater level and aquifer dewatering in Dhaka Metropolitan area, Bangladesh: causes and quantification. Hydrogeology J 15:1523-1534\u003c/li\u003e\n\u003cli\u003eHwang JH, Kihm YH (2005) Geological report of the Ganghwa\u0026middot;onsuri sheet. Korea Institute of Geoscience and Mineral Resources p.46\u003c/li\u003e\n\u003cli\u003eIdowu TE, Lasisi KH (2020) Seawater intrusion in the coastal aquifers of East and Horn of Africa: A review from a regional perspective. Scientific African. https://doi.org/10.1016/j.sciaf.2020.e00402\u003c/li\u003e\n\u003cli\u003eLee JT (2018) Hot spring investigation report of Ganghwa Yonggung area. Korea Institute of Geoscience and Mineral Resources p. 128 (in Korean)\u003c/li\u003e\n\u003cli\u003eLee JT (2017) Hot spring investigation report of Ganghwa Rian area. Korea Institute of Geoscience and Mineral Resources p. 91 (in Korean)\u003c/li\u003e\n\u003cli\u003eLogan J (1964) Estimating Transmissibility from Routine Production Tests of Water Wells. Ground Water 2:35\u0026ndash;37\u003c/li\u003e\n\u003cli\u003eSeong JS (2013) Hot spring investigation report of Ganghwa Haemyeong area. Korea Institute of Geoscience and Mineral Resources p. 76 (in Korean)\u003c/li\u003e\n\u003cli\u003eYuhara K, Seno K (1969) Geology, geophysics and geochemistry of hot and mineral springs. Chijinshokan \u0026amp; Co., Ltd, Tokyo p.293 (in Japanese)\u003c/li\u003e\n\u003cli\u003eZhang Y, Xue Y-Q, Wu J-C, Shi X-Q, Yu J (2010) Excessive groundwater withdrawal and resultant land subsidence in the Su-Xi-Chang area, China. Environ Earth Sci 61:1135-1143\u003c/li\u003e\n\u003cli\u003eZhang Y, Sun H, Shang Y (2022) Study on Siphon Drainage Capacity of Slopes with Long-Horizontal Pipe Sections. Appl Sci 12(19): 9650\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"geothermal water, tidal efficiency, naturally flowing water, water-level rise, pumping","lastPublishedDoi":"10.21203/rs.3.rs-4421971/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4421971/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eGroundwater levels rarely rise during pumping, and the underlying mechanism for their rise has not yet been revealed. Water level rise was observed during pumping at a deep geothermal well located approximately 1 km from the western coastline on Seokmo-do Island, Korea. We revealed the mechanism of the water level rise based on the relationship between the water level and tidal efficiency and the relationship between the flowing water temperature and the amount of naturally flowing water to the surface, considering the density and static pressure (\u003cem\u003eh\u003c/em\u003e) of water. When water was pumped out of the geothermal well over time, the temperature at 9 m depth increased, whereas the density of the water continuously decreased, and then \u003cem\u003eh\u003c/em\u003e increased. From the start of the natural flow, the water temperature in the well increased consistently along with a progressive increase in the amount of natural flow. When the temperature of naturally flowing water reaches\u0026thinsp;~\u0026thinsp;65.5℃, the rate of natural flow increases to ~\u0026thinsp;1,441 m\u003csup\u003e3\u003c/sup\u003e/d with \u003cem\u003e∆h\u003c/em\u003e of ~\u0026thinsp;22.3 m. \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eU\u003c/span\u003esing a simple formula of transmissivity and maximum drawdown during steady-state long-term pumping at a confined aquifer, the water level was 7.03 m above the land surface at a natural flow rate of 1441 m\u003csup\u003e3\u003c/sup\u003e/d.\u003c/p\u003e","manuscriptTitle":"Mechanism of geothermal water level rise induced by pumping in an island","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-05-27 07:14:41","doi":"10.21203/rs.3.rs-4421971/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"23c07e85-4d89-4f9c-8623-41bc18ad132d","owner":[],"postedDate":"May 27th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-09-21T05:55:16+00:00","versionOfRecord":[],"versionCreatedAt":"2024-05-27 07:14:41","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4421971","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4421971","identity":"rs-4421971","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}