Correlation of Water tables to Redoximorphic Features in the Dougherty Plain, Southwest Georgia

2015 ◽  
pp. 247-258 ◽  
Author(s):  
L. T. West ◽  
J. N. Shaw ◽  
E. R. Blood ◽  
L. K. Kirkman
Keyword(s):  
Redoximorphic Features ◽  
Water Tables

Application of a Simple Cold Stub to the Direct Observation of Frozen Hydrated Sand

1973 ◽  
Vol 31 ◽  
pp. 212-213
Author(s):  
John M. Wehrung ◽  
Richard J. Harniman
Keyword(s):  
United States ◽  
Surface Water ◽  
Direct Observation ◽  
Controlled Study ◽  
Clay Particles ◽  
Organic Debris ◽  
Rock Formations ◽  
Water Tables ◽  
Permeable Rock ◽  
Natural Means

Water tables in aquifer regions of the southwest United States are dropping off at a rate which is greater than can be replaced by natural means. It is estimated that by 1985 wells will run dry in this region unless adequate artificial recharging can be accomplished. Recharging with surface water is limited by the plugging of permeable rock formations underground by clay particles and organic debris.A controlled study was initiated in which sand grains were used as the rock formation and water with known clay concentrations as the recharge media. The plugging mechanism was investigated by direct observation in the SEM of frozen hydrated sand samples from selected depths.

scholarly journals Greenhouse Gas Balance of Sphagnum Farming on Highly Decomposed Peat at Former Peat Extraction Sites

Ecosystems ◽  
2021 ◽  
Author(s):  
Jan Oestmann ◽  
Bärbel Tiemeyer ◽  
Dominik Düvel ◽  
Amanda Grobe ◽  
Ullrich Dettmann
Keyword(s):  
Water Management ◽  
Drip Irrigation ◽  
Large Scale ◽  
Ghg Emissions ◽  
The Other ◽  
Ghg Mitigation ◽  
Greenhouse Gas Balance ◽  
Peat Extraction ◽  
Water Tables ◽  
Mitigation Potentials

AbstractFor two years, we quantified the exchange of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) at two different large-scale Sphagnum farming sites. At both, peat extraction left a shallow layer of highly decomposed peat and low hydraulic conductivities. One site was characterized by preceding multi-annual inundation and irrigated by ditches, while the other one was inoculated directly after peat extraction and irrigated by ditches and drip irrigation. Further, GHG emissions from an irrigation polder and the effect of harvesting Sphagnum donor material at a near-natural reference site were determined. GHG mitigation potentials lag behind the results of less decomposed sites, although our results were also affected by the extraordinary hot and dry summer 2018. CO2 exchanges ranged between -0.6 and 2.2 t CO2-C ha−1 y−1 and were mainly influenced by low water table depths. CH4 emissions were low with the exception of plots with higher Eriophorum covers, while fluctuating water tables and poorly developing plant covers led to considerable N2O emissions at the ditch irrigation site. The removal of the upper vegetation at the near-natural site resulted in increased CH4 emissions and, on average, lowered CO2 emissions. Overall, best plant growth and lowest GHG emissions were measured at the previously inundated site. At the other site, drip irrigation provided more favourable conditions than ditch irrigation. The size of the area needed for water management (ditches, polders) strongly affected the areal GHG balances. We conclude that Sphagnum farming on highly decomposed peat is possible but requires elaborate water management.

THE EFFECT OF GROUNDWATER ON SOIL FORMATION IN A MORAINAL LANDSCAPE IN SASKATCHEWAN

1985 ◽  
Vol 65 (2) ◽  
pp. 293-307 ◽  
Author(s):  
J. J. MILLER ◽  
D. F. ACTON ◽  
R. J. ST. ARNAUD
Keyword(s):  
Groundwater Flow ◽  
Water Table ◽  
Soil Formation ◽  
Lateral Flow ◽  
Dominant Factor ◽  
Slope Position ◽  
Soluble Salts ◽  
Runoff Water ◽  
Depth To Water Table ◽  
Water Tables

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

scholarly journals Charcoal in soils of the Allerød-Younger Dryas transition were the result of natural fires and not necessarily the effect of an extra-terrestrial impact

2008 ◽  
Vol 87 (4) ◽  
pp. 359-361 ◽  
Author(s):  
T. van der Hammen ◽  
B. van Geel
Keyword(s):  
North America ◽  
Large Scale ◽  
Sand Dunes ◽  
Younger Dryas ◽  
Natural Fires ◽  
Water Tables ◽  
Pine Trees ◽  
Climate Cooling ◽  
Fossil Records ◽  
Terrestrial Material

AbstractDuring the warm Bølling-Allerød interstadial, tree species migrated from their refugia in southern Europe northwards into the area within the present temperate climatic zone. It is evident from high levels of charcoal in fossil records in this region that, especially during the later part of the Bølling-Allerød interstadial, many fires occurred. The start of the Younger Dryas was characterised by rapid and intense cooling and rising water tables, with catastrophic effects on the vegetation. Thermophilous pine trees could not survive the cold Younger Dryas climate. Dead wood provided an abundant source of fuel for intense, large-scale fires seen in many records as a concentration of charcoal particles in so-called ’Usselo-soils’ dated to ca 10,95014C BP. A similar trend in increased charcoal indicating increased burning is seen at many sites across North America at this time and it has been suggested by Firestone et al. (2007) that this was caused by an explosion of extra-terrestrial material over northern North America, causing the Younger Dryas climate cooling and Megafaunal extinction. We argue that there is no need to invoke an extraterrestrial cause to explain the charcoal in the fossilized soils. The volume of forest trees that died as a result of the cold Younger Dryas climate would easily have supplied sufficient fuel for intense, large-scale fires and can be used to account for the concentration of charcoal particles. As soils were no longer covered by dense vegetation, much erosion occurred during the Younger Dryas and therefore, at many places, Usselo soils, rich in charcoal, were preserved under aeolian sand dunes.

Saltcedar (Tamarix spp.) Management with Imazapyr

1998 ◽  
Vol 12 (2) ◽  
pp. 337-344 ◽  
Author(s):  
Keith W. Duncan ◽  
Kirk C. McDaniel
Keyword(s):  
Cultural Practices ◽  
Field Trials ◽  
Western United States ◽  
Individual Plant ◽  
Stem Number ◽  
Recent Success ◽  
Water Tables ◽  
Tamarix Spp ◽  
Herbicide Activity ◽  
Herbicide Use

During the 20th century, naturalized saltcedar has become common within major tributaries throughout the western United States. Often growing in nearly monocultural stands, saltcedar is suspected of lowering water tables, thus destroying wetlands and wildlife habitats. Management efforts have primarily relied on mechanical and cultural practices, but recent success in controlling saltcedar with imazapyr has led to wider herbicide use. Based on a number of research/extension field trials in New Mexico from 1987 to present, imazapyr applied alone or in combination with glyphosate was found to control saltcedar to levels of 90% or greater, especially when applied in August or September. For fixed-wing aircraft applications, we recommend applying imazapyr at 1.1 kg ai/ha or imazapyr plus glyphosate at 0.56 plus 0.56 kg/ha. For individual plant treatments, we recommend spraying the foliage to wet with imazapyr at 1% v/v in water, or imazapyr plus glyphosate at 0.5 plus 0.5% v/v. Herbicide activity may be reduced as saltcedar height and stem number increases.

Liquid Contaminants Floating Upon the Water Tables

2020 ◽  
pp. 183-205
Author(s):  
Warren J. Lyman ◽  
Patrick J. Reidy ◽  
Benjamin Levy ◽  
Chi-Yuan Fan
Keyword(s):  
Water Tables

scholarly journals The role of hydrological transience in peatland pattern formation

2013 ◽  
Vol 1 (1) ◽  
pp. 29-43 ◽  
Author(s):  
P. J. Morris ◽  
A. J. Baird ◽  
L. R. Belyea
Keyword(s):  
Steady State ◽  
Hydraulic Properties ◽  
Three Dimensional ◽  
Structural Complexity ◽  
Plant Litter ◽  
Future Climate Change ◽  
Litter Production ◽  
Landscape Models ◽  
Water Tables

Abstract. The sloping flanks of peatlands are commonly patterned with non-random, contour-parallel stripes of distinct micro-habitats such as hummocks, lawns and hollows. Patterning seems to be governed by feedbacks among peatland hydrological processes, plant micro-succession, plant litter production and peat decomposition. An improved understanding of peatland patterning may provide important insights into broader aspects of the long-term development of peatlands and their likely response to future climate change. We recreated a cellular simulation model from the literature, as well as three subtle variants of the model, to explore the controls on peatland patterning. Our models each consist of three submodels, which simulate: peatland water tables in a gridded landscape, micro-habitat dynamics in response to water-table depths, and changes in peat hydraulic properties. We found that the strength and nature of simulated patterning was highly dependent on the degree to which water tables had reached a steady state in response to hydrological inputs. Contrary to previous studies, we found that under a true steady state the models predict largely unpatterned landscapes that cycle rapidly between contrasting dry and wet states, dominated by hummocks and hollows, respectively. Realistic patterning only developed when simulated water tables were still transient. Literal interpretation of the degree of hydrological transience required for patterning suggests that the model should be discarded; however, the transient water tables appear to have inadvertently replicated an ecological memory effect that may be important to peatland patterning. Recently buried peat layers may remain hydrologically active despite no longer reflecting current vegetation patterns, thereby highlighting the potential importance of three-dimensional structural complexity in peatlands to understanding the two-dimensional surface-patterning phenomenon. The models were highly sensitive to the assumed values of peat hydraulic properties, which we take to indicate that the models are missing an important negative feedback between peat decomposition and changes in peat hydraulic properties. Understanding peatland patterning likely requires the unification of cellular landscape models such as ours with cohort-based models of long-term peatland development.

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