Improved radar interpretations of water table depths and groundwater flow patterns with predictive equations

Author(s):  
James A. Doolittle ◽  
B. J. Jenkinson ◽  
D. P. Franzmeier ◽  
W. Lynn
2020 ◽  
Vol 30 (1) ◽  
pp. 109
Author(s):  
Luhut Pardamean Siringoringo ◽  
Sandi Maulana

Way Huwi Village is located in South Lampung, near the Institut Teknologi Sumatera (ITERA). The purposes of this research is to know the unconfined groundwater flow pattern and groundwater facies changes. We measured the depth of water table at nine dig wells, analyzed piper diagram for groundwater facies identification. Then, we integrated groundwater flow patterns and groundwater facies from each well to analyze groundwater facies change pattern in research area. The result indicated that the unconfined groundwater flows from SW to NE of research area, following higher (SW) to lower elevation (NE). There are six patterns of unconfined groundwater facies changes: from Facies Na-Cl to Facies Na-HCO3-Cl, Facies Na-HCO3-Cl to Facies Ca-Mg-HCO3, Facies Na-HCO3-Cl to Facies Na-Cl, Facies Na-HCO3-Cl to Facies Na-SO4-Cl, Facies Ca-Mg-HCO3 to Facies Na-SO4-Cl, and Facies Ca-Mg-HCO3 to Facies Na-HCO3-Cl. ABSTRAK - Pola aliran airtanah tidak tertekan dan perubahan fasiesnya di Desa Way Huwi, Lampung Selatan. Desa Way Huwi terletak di Lampung Selatan, di dekat Institut Teknologi Sumatera (ITERA). Tujuan dari penelitian ini adalah untuk mengetahui perubahan pola aliran airtanah dan fasies airtanah yang terjadi. Kami mengukur kedalaman muka airtanah pada sembilan sumur gali, menganalisis Diagram Piper untuk mengetahui fasies airtanah. Kemudian kami mengintegrasikan pola aliran airtanah dan fasies airtanah setiap sumur untuk mengetahui pola perubahan fasies air tanah. Hasil analisa menunjukkan bahwa airtanah tidak tertekan mengalir dari Barat Daya ke Timur Laut mengikuti ketinggian yang lebih tinggi (SW) ke ketinggian yang lebih rendah (NE). Ada enam pola perubahan fasies airtanah tidak tertekan: dari Facies Na-Cl ke Facies Na-HCO3-Cl, Facies Na-HCO3-Cl ke Facies Ca-Mg-HCO3, Facies Na-HCO3-Cl ke Facies Na-Cl, Facies Na -HCO3-Cl ke Facies Na-SO4-Cl, Facies Ca-Mg-HCO3 ke Facies Na-SO4-Cl, dan Facies Ca-Mg-HCO3 ke Facies Na-HCO3-Cl


2013 ◽  
Vol 17 (9) ◽  
pp. 3485-3498 ◽  
Author(s):  
B. J. Kopp ◽  
J. H. Fleckenstein ◽  
N. T. Roulet ◽  
E. Humphreys ◽  
J. Talbot ◽  
...  

Abstract. Long-term impacts of drier conditions on the hydrology of northern peatlands are poorly understood. We used long-term drainage near a historic drainage ditch, separating an area from the main peatland, as an analogue for long-term drying in a northern temperate bog. The objective was to identify the impact of drier conditions on ecohydrological processes and groundwater flow patterns in an area now forested and an area that maintained a bog-like character. Groundwater flow patterns alternated between mostly downward flow and occasionally upward flow in the bog area and were mostly upward-orientated in the forested area, which suggested that there the flow pattern had shifted from bog- to fen-like conditions. Flow patterns were in agreement with changes in post-drainage hydraulic conductivities, storage capacity of the peat and water table levels. Compared to the bog, hydraulic conductivities in the forested area were one to three orders of magnitude lower in the uppermost 0.75 m of peat (paired t test, p < 0.05). Bulk density had increased and the water table level was lower and more strongly fluctuating in the forested area. Our findings suggest hydraulic gradients and flow patterns have changed due to increased evapotranspiration and interception with the emergence of a tree cover. The smaller size of the now-forested area relative to the remaining bog area appeared to be important for the hydrological change. With the main Mer Bleue bog as hinterland, enhanced runoff to the drainage channel had little effect on hydrologic and vegetation patterns. In the cut-off, smaller, now forested area pervasive changes in vegetation and hydrologic processes occurred. The difference in response to local drainage raises questions about tipping points with respect to the impact of drying on peatland ecosystems that need to be addressed in future research.


1985 ◽  
Vol 65 (2) ◽  
pp. 293-307 ◽  
Author(s):  
J. J. MILLER ◽  
D. F. ACTON ◽  
R. J. ST. ARNAUD

The results of this study indicate the importance of groundwater flow and water table depth on the genesis, characteristics and distribution of soils within a hummocky morainal landscape. Non-saline and non-carbonated soils in upland depressions can be attributed to "depression-focused" recharge by snowmelt and snowmelt runoff in the spring, as evidenced by deep sola and/or eluvial horizons. Non-saline and carbonated soils on lower slopes adjacent to depressions are associated with local discharge and/or lateral flow from the adjacent groundwater mounds under the depressions in spring, as well as upward flow in the summer resulting from water use by phreatophytes such as willows, creating a water table depression around the slough fringes. Saline and carbonated soils at low elevations are associated with shallow and rather stable water tables, and local discharge from surrounding uplands. Soil types on uplands are more dependent on slope position and infiltration than on depth to water table or groundwater flow. Non-saline soils of different profile types occur on mid- and upper slope positions. These areas have a deep water table with mainly recharge or lateral flow occurring in the saturated zone. The infiltration of surface runoff water in upland depressions is the dominant factor influencing the distribution of soluble salts in this hummocky landscape. Key words: Water table, landscape position, recharge, discharge, soluble salts, soil genesis, morphology, carbonate soil


2021 ◽  
Author(s):  
Sandra Raab ◽  
Mathias Goeckede ◽  
Jorien Vonk ◽  
Anke Hildebrandt ◽  
Martin Heimann

&lt;p&gt;As a major reservoir for organic carbon, permafrost areas play a pivotal role in global climate change. Vertical carbon fluxes as well as lateral transport from land to groundwaters and surface waters towards the ocean are highly dependent on various abiotic and biotic factors. These include for example temperature, groundwater depth, or vegetation community. During summer months, when soils thaw and lateral carbon transport within suprapermafrost groundwater bodies and surface waters occurs, flow patterns and therefore carbon redistribution may differ significantly between dry and wet conditions. Since dry soil conditions are expected to become more frequent in the future, associated shifts in carbon transport patterns play an important role in quantifying the carbon input into the water body linked to permafrost degradation.&lt;/p&gt;&lt;p&gt;This study focuses on hydrological and carbon transport patterns within a floodplain tundra site near Chersky, Northeast Siberia. We compared a wet control site with a site affected by a drainage ring built in 2004 to study the effect of water availability on carbon production and transport. Water table depths at both sites were continuously monitored with a distributed sensor network over the summer seasons 2016-2020. At several locations, water samples were collected in 2016 and 2017 to determine organic carbon concentrations (DOC) as well as carbon isotopes (e.g. &amp;#8710;&lt;sup&gt;14&lt;/sup&gt;C-DOC). Suprapermafrost groundwater and surface water from the drainage ditch and the nearby Ambolikha river were included in the analysis.&lt;/p&gt;&lt;p&gt;Our results focus on the physical hydrological conditions as well as on DOC and &amp;#8710;&lt;sup&gt;14&lt;/sup&gt;C-DOC observations. The spatio-temporal dynamics of water table depth revealed systematic differences between control and drained sites. The drained area showed a stronger decrease in water tables towards peak summer season in July and stronger reactions to precipitation events. The control area responded less pronounced to short-term changes. At the drained site, the main groundwater flow direction was stable throughout the measurement period. The control site was characterized by a shift in water flow confluence depending on increasing and decreasing water levels. DOC and &amp;#8710;&lt;sup&gt;14&lt;/sup&gt;C-DOC data showed that the highest concentrations of organic carbon and oldest DOC can be found in late summer. DOC concentrations were higher at the drained site compared to the wet site. We will show that the distribution of dissolved carbon can be directly related to hydrological flow patterns, and that understanding of these redistribution processes is essential for interpreting the carbon budget in disturbed permafrost.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;


1995 ◽  
Vol 32 (6) ◽  
pp. 957-975 ◽  
Author(s):  
L.D. McKay ◽  
J. Fredericia

In the unconsolidated clay-rich glacial deposits underlying a site in southwestern Ontario, fractures and root casts greatly influence hydraulic conductivity and groundwater flow. The fractures are predominantly vertical and have visible oxidation staining from surface to a depth of 6 m. Root casts commonly occur along fracture surfaces in the upper 3 m, but can also occur as holes in apparently unfractured blocks. The fractures are believed caused mainly by dessication during past periods of low water table. This hypothesis is supported by a decrease in fracture density with depth and the presence of a stiff crust, presumably caused by desiccation-induced consolidation. The random pebble fabric and faint layering indicate deposition in a calm lacustrine environment, which precludes the possibility of the fractures having been caused by overriding ice. Fractures were found below the depth of oxidation staining (6 m) but most of these appear to have been caused by stress-relief due to the excavation and subsequent drying. In the upper 3 m the fractures and root casts are responsible for field-measured hydraulic conductivity values that are up to 3 orders of magnitude greater than measured in the laboratory for samples of the unfractured matrix. High values of field-measured hydraulic conductivity, seasonal head variations greater than 0.5 m, and high tritium content all persist below the depth of root casts, indicating that hydraulically conductive fractures do exist to depths of at least 6 m and possibly as great as 12–15 m, which is well below the depth of oxidation staining. However, there is some uncertainty in this assessment of the extent of hydraulically conductive fractures because of the sensitivity to small leaks in the piezometer installations. Key words : clay, glacial, fractures, desiccation, hydraulic conductivity.


2012 ◽  
Vol 27 (24) ◽  
pp. 3475-3483 ◽  
Author(s):  
Xing Liang ◽  
Dongjie Quan ◽  
Menggui Jin ◽  
Yan Liu ◽  
Renquan Zhang

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