scholarly journals A Hydrologic Landscapes Perspective on Groundwater Connectivity of Depressional Wetlands

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 50 ◽  
Author(s):  
Brian P. Neff ◽  
Donald O. Rosenberry ◽  
Scott G. Leibowitz ◽  
Dave M. Mushet ◽  
Heather E. Golden ◽  
...  
Keyword(s):  
Surface Water ◽  
Water Table ◽  
Conceptual Knowledge ◽  
Groundwater Discharge ◽  
Depressional Wetlands ◽  
Hydrologic Connectivity ◽  
Site Specific ◽  
Depressional Wetland ◽  
Resource Managers ◽  
Flow Through

Research into processes governing the hydrologic connectivity of depressional wetlands has advanced rapidly in recent years. Nevertheless, a need persists for broadly applicable, non-site-specific guidance to facilitate further research. Here, we explicitly use the hydrologic landscapes theoretical framework to develop broadly applicable conceptual knowledge of depressional-wetland hydrologic connectivity. We used a numerical model to simulate the groundwater flow through five generic hydrologic landscapes. Next, we inserted depressional wetlands into the generic landscapes and repeated the modeling exercise. The results strongly characterize groundwater connectivity from uplands to lowlands as being predominantly indirect. Groundwater flowed from uplands and most of it was discharged to the surface at a concave-upward break in slope, possibly continuing as surface water to lowlands. Additionally, we found that groundwater connectivity of the depressional wetlands was primarily determined by the slope of the adjacent water table. However, we identified certain arrangements of landforms that caused the water table to fall sharply and not follow the surface contour. Finally, we synthesize our findings and provide guidance to practitioners and resource managers regarding the management significance of indirect groundwater discharge and the effect of depressional wetland groundwater connectivity on pond permanence and connectivity.

scholarly journals WATER EXCHANGE IN THE ESTUARY OF THE RAZDOLNAYA RIVER (AMUR BAY, JAPAN SEA) IN THE ICE COVERED PERIOD

2019 ◽  
Vol 196 ◽  
pp. 123-137 ◽  
Author(s):  
P. Yu. Semkin ◽  
P. Ya. Tishchenko ◽  
V. B. Lobanov ◽  
Yu. A. Barabanshchikov ◽  
T. A. Mikhailik ◽  
...  
Keyword(s):  
Water Exchange ◽  
Salt Water ◽  
Groundwater Discharge ◽  
River Mouth ◽  
Japan Sea ◽  
Bottom Layer ◽  
Additional Source ◽  
Flow Through ◽  
Limited Water Exchange ◽  
Annual Discharge

Environmental conditions in the Razdolnaya/Suifen Estuary and adjacent marine area were monitored from 2008 to 2018, by seasons, including winter observations in January 2014 and January 2018. The river discharge in winter was low: 6 m3 /s (mean annual discharge is 73 m3 /s). The estuary was covered by ice. The cline of salt water at the bottom was traced upstream up to 28 km from the river mouth. The currents in the estuary changed in tidal cycle. Increasing of salinity and temperature (> 2о ) at the bottom was observed in the distance 20–24 km from the river bar (this area was distinguished by relatively thin ice, 20 cm, against 40–70 cm in the rest of estuary). Modeling of the water balance in the estuary showed an additional source of salt water in the internal estuary, beyond the direct exchange with the sea over the river bar, that was presumably the water flow through the aquifer. This groundwater discharge was responsible for supporting of the salted bottom layer and for temperature and salinity increasing in the internal estuary during the ebb phase in conditions of limited water exchange by two-layered estuarine circulation because of ice cover at the river mouth.

scholarly journals Combining Multi-Sensor Satellite Imagery to Improve Long-Term Monitoring of Temporary Surface Water Bodies in the Senegal River Floodplain

2020 ◽  
Vol 12 (19) ◽  
pp. 3157
Author(s):  
Andrew Ogilvie ◽  
Jean-Christophe Poussin ◽  
Jean-Claude Bader ◽  
Finda Bayo ◽  
Ansoumana Bodian ◽  
...  
Keyword(s):  
Surface Water ◽  
Water Bodies ◽  
Landsat 8 ◽  
Site Specific ◽  
Senegal River ◽  
Landsat 7 ◽  
Long Term Monitoring ◽  
Term Monitoring ◽  
Sentinel 2

Accurate monitoring of surface water bodies is essential in numerous hydrological and agricultural applications. Combining imagery from multiple sensors can improve long-term monitoring; however, the benefits derived from each sensor and the methods to automate long-term water mapping must be better understood across varying periods and in heterogeneous water environments. All available observations from Landsat 7, Landsat 8, Sentinel-2 and MODIS over 1999–2019 are processed in Google Earth Engines to evaluate and compare the benefits of single and multi-sensor approaches in long-term water monitoring of temporary water bodies, against extensive ground truth data from the Senegal River floodplain. Otsu automatic thresholding is compared with default thresholds and site-specific calibrated thresholds to improve Modified Normalized Difference Water Index (MNDWI) classification accuracy. Otsu thresholding leads to the lowest Root Mean Squared Error (RMSE) and high overall accuracies on selected Sentinel-2 and Landsat 8 images, but performance declines when applied to long-term monitoring compared to default or site-specific thresholds. On MODIS imagery, calibrated thresholds are crucial to improve classification in heterogeneous water environments, and results highlight excellent accuracies even in small (19 km2) water bodies despite the 500 m spatial resolution. Over 1999–2019, MODIS observations reduce average daily RMSE by 48% compared to the full Landsat 7 and 8 archive and by 51% compared to the published Global Surface Water datasets. Results reveal the need to integrate coarser MODIS observations in regional and global long-term surface water datasets, to accurately capture flood dynamics, overlooked by the full Landsat time series before 2013. From 2013, the Landsat 7 and Landsat 8 constellation becomes sufficient, and integrating MODIS observations degrades performance marginally. Combining Landsat and Sentinel-2 yields modest improvements after 2015. These results have important implications to guide the development of multi-sensor products and for applications across large wetlands and floodplains.

Mineralogical and textural evolution of the economic manganese mineralisation in western Rhodope massif, N. Greece

1991 ◽  
Vol 55 (380) ◽  
pp. 423-434 ◽  
Author(s):  
M. K. Nimfopoulos ◽  
R. A. D. Pattrick
Keyword(s):  
Surface Water ◽  
Water Table ◽  
Fault Zones ◽  
Hydrothermal Fluids ◽  
Mineral Paragenesis ◽  
Textural Evolution ◽  
Mn Oxide ◽  
Alkaline Earths ◽  
Mn Oxides ◽  
Hydrothermal Veins

AbstractThe western Rhodope massif contains a significant number of ‘battery grade’ Mn-oxide deposits which are best developed in the area near Kato Nevrokopi, Drama district, N. Greece. Economic Mn-oxide ore concentrations are confined to fault zones and related karsts in marbles. The mineralisation has formed by weathering of hydrothermal veins that were genetically related to Oligocene magmatism.At Kato Nevrokopi, progressive and continuous weathering of primary, hydrothermal veins of rhodochrosite, mixed sulphide, quartz and ‘black calcite’ (calcite and todorokite) has resulted in the formation of the assemblage MnO-gel-(amorphous Mn-oxide)-todorokite-azurite-goethite-cerussite in the veins and the assemblage MnO-gel-nsutite-chalcophanite-birnessite-cryptomelane-pyrolusite and malachite and amorphous Fe-oxides in karstic cavities.The fs2 and fO2 of the hydrothermal fluids increased with time. The breakdown of the hypogene Mn-carbonate was aided by the production of an acidic fluid due to the oxidation of sulphides. Precipitation of the supergene ores was caused by neutralisation of the fluids due to reaction with the host marble and to mixing of relatively reduced fluids with oxygenated surface water in a fluctuation water table regime. Zinc was also mobile during weathering and became concentrated in the intermediate Mn-oxides, effectively stabilising their structures. The mineral paragenesis records the progressive oxidation of the ore and the appearance of less hydrated Mn-oxides, low in alkalis and alkaline earths.

scholarly journals Visual drainage assessment: A standardised visual soil assessment method for use in land drainage design in Ireland

2016 ◽  
Vol 55 (1) ◽  
pp. 24-35 ◽  
Author(s):  
P. Tuohy ◽  
J. Humphreys ◽  
N.M. Holden ◽  
J. O’Loughlin ◽  
B. Reidy ◽  
...  
Keyword(s):  
Water Table ◽  
Discharge Capacity ◽  
Drainage System ◽  
Assessment Method ◽  
Site Specific ◽  
Soil Assessment ◽  
Land Drainage ◽  
Standard Design ◽  
Rainfall Recharge ◽  
A Site

AbstractThe implementation of site-specific land drainage system designs is usually disregarded by landowners in favour of locally established ‘standard practice’ land drainage designs. This is due to a number of factors such as a limited understanding of soil–water interactions, lack of facilities for the measurement of soil’s physical or hydrological parameters and perceived time wastage and high costs. Hence there is a need for a site-specific drainage system design methodology that does not rely on inaccessible, time-consuming and/or expensive measurements of soil physical or hydrological properties. This requires a standardised process for deciphering the drainage characteristics of a given soil in the field. As an initial step, a new visual soil assessment method, referred to as visual drainage assessment (VDA), is presented whereby an approximation of the permeability of specific soil horizons is made using seven indicators (water seepage, pan layers, texture, porosity, consistence, stone content and root development) to provide a basis for the design of a site-specific drainage system. Across six poorly drained sites (1.3 ha to 2.6 ha in size) in south-west Ireland a VDA-based design was compared with (i) an ideal design (utilising soil physical measurements to elucidate soil hydraulic parameters) and (ii) a standard design (0.8 m deep drains at a 15 m spacing) by model estimate of water table control and rainfall recharge/drain discharge capacity. The VDA method, unlike standard design equivalents, provided a good approximation of an ideal (from measured hydrological properties) design and prescribed an equivalent land drainage system in the field. Mean modelled rainfall recharge/drain discharge capacity for the VDA (13.3 mm/day) and ideal (12.0 mm/day) designs were significantly higher (P< 0.001, s.e. 1.42 mm/day) than for the standard designs (0.5 mm/day), when assuming a design minimum water table depth of 0.45 m.

Thermal infrared video details multiscale groundwater discharge to surface water through macropores and peat pipes

2016 ◽  
Vol 30 (14) ◽  
pp. 2510-2511 ◽  
Author(s):  
Martin A. Briggs ◽  
Danielle K. Hare ◽  
David F. Boutt ◽  
Glorianna Davenport ◽  
John W. Lane
Keyword(s):  
Surface Water ◽  
Groundwater Discharge ◽  
Thermal Infrared ◽  
Infrared Video
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