Characterizing groundwater heat-transport in a complex lowland aquifer using paleo-temperature reconstruction, satellite data, temperature-depth profiles, and numerical models

Heat is a naturally occurring widespread groundwater tracer that can be used to identify flow patterns in groundwater systems. Temperature measurements, being relatively inexpensive and effortless to gather, represent a valuable source of information which can be exploited to reduce uncertainties on groundwater flow, and e.g. support performance assessment studies on waste disposal sites. In a lowland setting, however, hydraulic gradients are typically small, and whether temperature measurements can be used to inform us about catchment-scale groundwater flow remains an open question. For the Neogene aquifer in Flanders, groundwater flow and solute transport models have been developed in the framework of safety and feasibility studies for the underlying Boom Clay Formation as potential host rock for geological disposal of radioactive waste. However, the simulated fluxes by these models are still subject to large uncertainties, as they are typically constrained by hydraulic heads only. In the current study we use a state-of-the-art 3D steady-state groundwater flow model, calibrated against hydraulic head measurements, to build a 3D transient heat-transport model, for assessing the use of heat as an additional state variable, in a lowland setting, at the catchment scale. We therefore use temperature-depth (TD) profiles as additional state variable observations for inverse conditioning. Furthermore, a Holocene paleo-temperature time curve was constructed based on paleo-temperature reconstructions in Europe from several sources in combination with land-surface temperature (LST) imagery remote sensing monthly data from 2001 to 2019 (retrieved from NASA’s MODIS). The aim of the research is to understand the mechanisms of heat transport and to characterize the temperature distribution and dynamics in the Neogene aquifer. The simulation results clearly underline advection/convection and conduction as the major heat transport mechanisms, with a reduced role of advection/convection in zones where flux magnitudes are low, which suggests temperature is a useful indicator also in a lowland setting. Furthermore, performed scenarios highlight the important roles of i) surface hydrological features and withdrawals driving local groundwater flow systems, and ii) the inclusion of subsurface features like faults in the conceptualization and development of hydrogeological investigations. These findings serve as a proxy of the influence of advective transport and barrier/conduit role of faults, particularly the Rauw Fault in this case, and suggest that solutes released from the Boom Clay might be affected in similar ways.

Kajian Kualitas Air Berdasarkan Keanekaragaman Meiofauna dan Parameter Fisika-Kimia di Pesisir Losari, Makassar

Pesisir merupakan kawasan yang rentan mengalami penurunan kualitas perairan akibat masuknya bahan-bahan pencemar hasil aktivitas antropogenik dari daratan. Penelitian ini bertujuan untuk untuk mengkaji kualitas perairan berdasarkan keanekaragaman meiofauna dan parameter fisika-kimia di pesisir Losari, Makassar. Selain itu penelitian ini dilakukan untuk menganalisis pengaruh parameter fisika-kimia terhadap keanekaragaman meiofauna di dasar perairan. Penelitian ini bersifat kuantitatif dengan teknik pengambilan data secara purposive sampling. Status kualitas perairan di pesisir Losari dikategorikan sebagai perairan yang tercemar berat, hal ini didasarkan pada tingkat keanekaragaman spesies meiofauna yang sangat rendah dan sebagian besar parameter fisika-kimia perairan yang tidak memenuhi baku mutu yang telah ditentukan oleh pemerintah RI melalui Kep. MLH. No. 51 Tahun 2004. Kecerahan, DO, Suhu, kedalaman, salinitas, dan nitrat sedimen merupakan parameter fisika-kimia yang berkorelasi positif atau berpengaruh terhadap tingkat keanekaragaman meiofauna. Adapun parameter lingkungan perairan yang berkorelasi negatif terhadap tingkat keanekaragaman meiofauna di pesisir Losari, diartikan sebagai hubungan yang tidak menguntungkan. Kondisi ini terjadi akibat meiofauna merasa terganggu atas sebaran fosfat sedimen, nitrat air laut, fosfat air laut, dan pH yang tidak memenuhi baku mutu air laut.ABSTRACTThe Coastal zone are susceptible to decreasing water quality due entry of pollutants from anthropogenic activities in the mainland. This study assessed water quality based on meiofauna diversity and physical-chemical parameters in the Losari coast, Makassar. Furthermore, this study was to analyze the physical-chemical parameters effect on the diversity of meiofauna at the seabed. It employed a quantitative approach with purposive sampling technique. Water quality status on the Losari coast categorized as heavily polluted waters, this based on low level of meiofauna species diversity and most of the physical-chemical parameters does not meet the quality standards determined by Indonesian government through Kep. MLH. No. 51 of 2004. Brightness, DO, temperature, depth, salinity, and sediment nitrate are physical-chemical parameters positively correlated or influenced of meiofauna diversity level. The aquatic environmental parameters negatively correlated with meiofauna diversity level in the Losari coast are interpreted as an unfavorable relationship. This condition occurs because the meiofauna feel disturbed by distribution of sedimentary phosphate, seawater nitrate, seawater phosphate, and pH that does not meet seawater quality regulations.

Percampuran vertikal di Perairan Laut Maluku dan Talaud pada bulan Februari 2021

<strong>Vertical mixing in the northern Maluku Sea and Talaud Waters in February 2021. </strong>The spatial variability of water mass mixing in the northern Maluku Sea and Talaud waters are presented based on the results of Eastern Indonesia Expedition (EIT) 2021 using RV Baruna Jaya VIII-LIPI. The turbulent kinetic energy dissipation rate was obtained using the Kunze-Williams-Briscoe (KWB) Method calculated from CTD (Conductivity, Temperature, Depth) and LADCP (Lowered Acoustic Doppler Current Profiler) datasets. We found the dissipation rate in the core layer of North Pacific Subtropical Water (NPSW) and North Pacific Intermediate Water (NPIW) are in the order of 10^-6 W/kg and 10^-8 W/kg, respectively. The KWB Method used in this study is also proven comparable with the Thorpe Method.

Water Availability Forecasting Using Univariate and Multivariate Prophet Time Series Model for ACEA (European Automobile Manufacturers Association)

Time series is one of method to forecasting the data. The ACEA company has competition with opened the data in the Water Availability and uses the data to forecast. The dataset namely, Aquifers-Petrignano in Italy in water resources field has five parameters e.g. rainfall, temperature, depth to groundwater, drainage volume, and river hydrometry. In our research will be forecast the depth to groundwater data using univariate and multivariate approach of time series using Prophet Method. Prophet method is one of library which develop by Facebook team. We also use the other approach to making the data clean, or the data ready to forecast. We use handle missing data, transforming, differencing, decomposition time series, determine lag, stationary approach, and Augmented Dickey-Fuller (ADF). The all approach will be uses to make sure that the data not appearing the problem while we tried to forecast. In the other describe, we already get the results using univariate and multivariate Prophet method. The multivariate approach has presented the value of MAE 0.82 and RMSE 0.99, it’s better than while we forecast using univariate Prophet.

Subsurface Ocean Characteristic in the Mentawai Waters during Monsoon Transition Phase on Last 2020

The Indonesia Continental Shelf (LKI) expedition was held during September - October 2020. During the survey, there were ten Conductivity Temperature Depth (CTD) measurement stations that located extending from the west of Mentawai Island to the Indian Ocean. In this study, two-line of subsurface temperature, salinity, and density data were plotted longitudinally. The results show the unique feature between the open ocean and coastal area, the characteristic from open ocean did not affect the characteristic in coastal zone, it is shown from the salinity data. The maximum salinity found in the thermocline layer, between 100-150 m in both of line. The salinity increases from the surface until the thermocline, then slightly decreases to the deep layer. The surface salinity in the coastal area significantly different from the open ocean, it is less than 34 PSU. That is the fact that Wyrtki Jet current did not induce the open ocean water to the coastal water in the subsurface. Otherwise, the temperature and density have a similar pattern with range values around 9-31°C.

Estimation of subsurface flow from high-resolution temperature profiles

Subsurface flow rates are critical for hydrology and geothermal research, while field characterization remains a challenge. There are several analytical solutions for calculating the vertical water flux based on measured temperatures. Heat is a popular natural tracer to estimate subsurface flow rates. However, quantifying flow rates is impeded by insufficient sensors spacing during field investigations or simplifying assumptions for analysis such as sinusoidal temperature boundary. The objective of this study is to develop a convenient method to investigate subsurface flow on the sub-meter scale. Here, we present a program to estimate water fluxes based on temperature-depth profiles, so-called TempFlow. TempFlow is a numerical program written in MATLAB that calculates steady state flow in transient heat tracing based on the inversion of measured high-resolution temperature-depth series observed at a certain time. In this program, the Fiber Optic Distributed Temperature Sensing (FO-DTS) is recommended for temperature collection. FO-DTS techniques provide high-resolution temperature measurements with continuous temperature profiles that account for sub-meter scale and nonperiodic boundary conditions in saturated sediments. The estimated subsurface flow using TempFlow was validated in a medium-scale tank with a series of experiments, where the hydraulic and temperature boundary conditions were well-controlled. The results indicate that the estimation using TempFlow obtained similar results as the experiments. Thus, the method could potentially be used to determine the flow rate of the subsurface.

THE PERFORMANCE OF MACROZOOBENTOS AS A BIOINDICATOR OF WATER QUALITY IN THE LOWER PARTS OF THE HURUN LAMPUNG RIVER

Macrozoobenthos is one of the organisms that can be used as biological indicators because it tends to live in an area and has sensitivity to environmental changes. The Hurun River had many community activities. Based on this, it was necessary to analyze the diversity of macrozoobenthos which will be compared with the physical and chemical parameters of water in order to find out the indicators that affect the abundance of macrozoobenthos in the river. The purpose of this research was to determine the macrozoobenthic community structure which found in the Hurun River based on diversity, uniformity and dominance indices, to build multiple linear regression models, and to determine the bioindicators of pollution in the Hurun River. The factors that influence the abundance of macrozoobenthos are temperature, depth, brightness, DO, TOM, and salinity. The types of macrozoobenthos obtained were 87 species with the highest abundance of macrozoobenthic animals of 70,666.56 ind/m3 while the lowest abundance of macrozoobenthic animals was 13,000.96 ind/m3. Based on data analysis, the macrozoobenthic diversity index was included in the medium category, the level of macrozoobenthic uniformity was included in the high, medium, and low categories, and the dominance level which was included in the medium and low categories. Multiple regression models with a confidence level of 5% get R2 results of 0.86. The level of pollution that occured in the Hurun River based on bioindicators with the ABC curve shows moderately polluted.

Karakteristik Oseanografi Laut Banda Bagian Barat Pada Musim Barat dari Data Pengukuran In-Situ 2016

Perairan Laut Banda bagian barat merupakan lokasi fishing ground potensial nelayan yang berpangkalan di Kendari dan sekitarnya. Karakteristik oseanografi perairan ini penting diketahui, terutama pada muson barat, karena masih sedikit data hasil kajian berbasis pengukuran in-situ. Penelitian ini dilaksanakan pada 4–17 Februari 2016 (akhir musim barat) dengan cruise kapal riset KR. Baruna Jaya VII-LIPI. Sampling dilakukan pada 19 stasiun oseanografi menggunakan Conductivity Temperature Depth (CTD) SBE 911 plus untuk mengukur suhu, konduktivitas, tekanan, fluorometer, turbiditas, transmisi cahaya dan oksigen terlarut (DO). Pengukuran arus permukaan menggunakan current meter type AEM-USB JFE Advantech. Pengolahan data CTD dilakukan dengan software SBE Data Processing dan analisa serta visualisasi data dilakukan menggunakan software Ocean data View (ODV). Hasil menunjukkan, secara vertikal kedalaman lapisan tercampur (mixed layer) berada sampai kedalaman 70m. Fluktuasi terbesar suhu berada pada kedalaman 125 m sebesar 20.40 oC dengan simpangan baku 1.085 oC, menunjukkan lapisan termoklin berada cukup dalam. Parameter salinitas, menunjukkan fluktuasi terbesarnya berada di kedalaman 50 m (rerata 34.27 psu dan simpangan baku 0.578 psu). Dari lapisan termoklin hingga 500 m tidak ditemukan ciri massa air bersalinitas tinggi yang berasal dari Pasifik Utara/Selatan. Kandungan oksigen maksimum berada pada isopiknal <5. Kandungan klorofil maksimum umumnya berada di sekitar isopycnal 22. Secara horizontal, nilai sebaran suhu permukaan laut (SPL) rata-rata 29.64 0C dengan pola nilai sebaran yang semakin tinggi ke arah daratan. Rata-rata salinitas permukaan 33.58 psu dengan pola makin tinggi ke arah tengah perairan. Nilai sebaran rata-rata kandungan oksigen terlarut (DO) sebesar 6.88 mg/l. Kecepatan arus permukaan berkisar 0.4–0.8 m/detik cenderung bergerak ke arah selatan, kecuali di stasiun bagian selatan Kepulauan Wakatobi arus menuju utara, terkait masih adanya pengaruh dorongan massa air dari Laut Flores. Nilai sebaran klorofil permukaan rata-rata 0.13 mg/m3 lebih rendah dibandingkan nilai rerata di perairan Indonesia pada musim barat. Pada akhir musim barat ini, tidak ditemukan adanya indikasi upwelling.

Pengaruh Kualitas Perairan Terhadap Distribusi Vertikal Plankton di Samudera Hindia Bagian Selatan Indonesia

Perairan selatan Indonesia memiliki kondisi batimetri yang unik, begitu pula dengan kondisi kualitas perairan di dalamnya yang selanjutnya akan mempengaruhi biota perairan. Penelitian dilakukan pada April 2008 dengan menempatkan 4 titik stasiun, dari mulai Selat Sunda hingga menuju ke Pameungpeuk Garut yang merupakan daerah Samudera Hindia. Pengamatan terhadap kualitas air dilakukan dengan menggunakan Conductivity Temperature Depth (CTD), sedangkan pengamatan plankton dilakukan dengan sampling plankton menggunakan Rosette Sampler. Profil suhu dan salinitas menunjukkan adanya perubahan nilai pada kedalaman sekitar 75 m. Plankton yang paling banyak ditemukan adalah genus Chaetoceros. Kelimpahan fitoplankton tertinggi adalah 6.825 ind/L yang terjadi pada kedalaman 50 m di stasiun 5 dan kelimpahan zooplankton tertinggi adalah 1.708 ind/L yang terjadi pada kedalaman 50 m di stasiun 3. Sebaran horizontal menunjukkan semakin dekat daratan, suhu bernilai tinggi dan salinitas bernilai rendah.