On the long-term hydraulic gradient in the thick clayey aquitard in the Sarnia region, Ontario

1998 ◽  
Vol 35 (6) ◽  
pp. 986-1003 ◽  
Author(s):  
Muin M Husain ◽  
John A Cherry ◽  
Scott Fidler ◽  
Shaun K Frape
Keyword(s):  
Water Use ◽  
Hydraulic Gradient ◽  
Water Levels ◽  
Transient Condition ◽  
Large Area ◽  
Bottom Part ◽  
Transport Modelling ◽  
Well Drilling ◽  
Potentiometric Surface

Much of the southwestern part of Ontario between Lake Huron and Lake Erie has a thin freshwater aquifer overlain by an aquitard of Late Pleistocene clayey glaciolacustrine deposits and underlain by a thick Devonian shale aquitard. In a large area east of the St. Clair River, where the Quaternary aquitard is 30-50 m thick, groundwater of Pleistocene origin (identified by 18O and 2H signature) occurs in the aquifer and in the bottom part of the Quaternary aquitard. Numerous piezometer nests in the aquitard show a downward hydraulic gradient with depth. In some areas, the aquitard has downward gradients only in the upper part and upward gradient in the lower part, indicating a transient condition. The piezometer nests in the clayey aquitard also show an increase in Cl- concentration with depth. Long-term piezometer monitoring at two sites show a major shift in the aquitard hydraulic gradient since 1983 and a large rise in head in the underlying aquifer. Analyses of initial aquifer water levels, reported in well drilling records, indicate a large decline in the potentiometric surface of the aquifer between the 1940's and the 1970's followed by a recent rise in the surface in part of the region. This pattern is consistent with well drilling and water use records indicating that 7000 wells were installed in the aquifer in the three decades since 1940 and that groundwater use has greatly diminished in the past 10-15 years due to rural pipeline distribution of lake and river water. The hydraulic gradient in the aquitard is slowly adjusting to the rise in the aquifer potentiometric surface. One-dimensional solute transport modelling provides close matches to the vertical profiles of Cl- migrating upward from the aquifer since deglaciation, 15 000 - 18 000 years before present, by diffusion with little or no advection. The lack of advection indicates a near-neutral long-term hydraulic gradient. As the withdrawal rate of water from the aquifer continues to decline, it is expected that the hydraulic head in the aquitard in much of the area westward of the recharge area will continue to adjust for many decades.Key words: clay, aquitard, aquifer, water use, hydraulic gradient.

scholarly journals Overexpression of MdATG8i improves water use efficiency in transgenic apple by modulating photosynthesis, osmotic balance, and autophagic activity under moderate water deficit

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xin Jia ◽  
Ke Mao ◽  
Ping Wang ◽  
Yu Wang ◽  
Xumei Jia ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Deficit ◽  
Water Use ◽  
Photosynthetic Capacity ◽  
Critical Role ◽  
Drought Conditions ◽  
Moderate Drought ◽  
Use Efficiency ◽  
Autophagic Activity

AbstractWater deficit is one of the major limiting factors for apple (Malus domestica) production on the Loess Plateau, a major apple cultivation area in China. The identification of genes related to the regulation of water use efficiency (WUE) is a crucial aspect of crop breeding programs. As a conserved degradation and recycling mechanism in eukaryotes, autophagy has been reported to participate in various stress responses. However, the relationship between autophagy and WUE regulation has not been explored. We have shown that a crucial autophagy protein in apple, MdATG8i, plays a role in improving salt tolerance. Here, we explored its biological function in response to long-term moderate drought stress. The results showed that MdATG8i-overexpressing (MdATG8i-OE) apple plants exhibited higher WUE than wild-type (WT) plants under long-term moderate drought conditions. Plant WUE can be increased by improving photosynthetic efficiency. Osmoregulation plays a critical role in plant stress resistance and adaptation. Under long-term drought conditions, the photosynthetic capacity and accumulation of sugar and amino acids were higher in MdATG8i-OE plants than in WT plants. The increased photosynthetic capacity in the OE plants could be attributed to their ability to maintain optimal stomatal aperture, organized chloroplasts, and strong antioxidant activity. MdATG8i overexpression also promoted autophagic activity, which was likely related to the changes described above. In summary, our results demonstrate that MdATG8i-OE apple lines exhibited higher WUE than WT under long-term moderate drought conditions because they maintained robust photosynthesis, effective osmotic adjustment processes, and strong autophagic activity.

Evaluation of long-term climate change impact on the growing season and water use of mature pecan in Lower Rio Grande Valley

2021 ◽  
Vol 252 ◽  
pp. 106893
Author(s):  
Esmaiil Mokari ◽  
Zohrab Samani ◽  
Richard Heerema ◽  
Frank Ward
Keyword(s):  
Climate Change ◽  
Water Use ◽  
Climate Change Impact ◽  
Rio Grande Valley ◽  
Rio Grande ◽  
Growing Season ◽  
Lower Rio Grande Valley ◽  
Change Impact ◽  
Lower Rio Grande

scholarly journals Effect of Deficit Irrigation and Reduced N Fertilization on Plant Growth, Root Morphology and Water Use Efficiency of Tomato Grown in Soilless Culture

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 228
Author(s):  
Ikram Ullah ◽  
Hanping Mao ◽  
Ghulam Rasool ◽  
Hongyan Gao ◽  
Qaiser Javed ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Irrigation Water ◽  
N Fertilization ◽  
Water Levels ◽  
Growth And Yield ◽  
Root Surface Area ◽  
Irrigation Water Use Efficiency ◽  
Irrigation Water Use ◽  
Use Efficiency

This study was conducted to investigate the effects of various irrigation water (W) and nitrogen (N) levels on growth, root-shoot morphology, yield, and irrigation water use efficiency of greenhouse tomatoes in spring–summer and fall–winter. The experiment consisted of three irrigation water levels (W: 100% of crop evapotranspiration (ETc), 80%, and 60% of full irrigation) and three N application levels (N: 100%, 75%, and 50% of the standard nitrogen concentration in Hoagland’s solution treatments equivalent to 15, 11.25, 7.5 mM). All the growth parameters of tomato significantly decreased (p < 0.05) with the decrease in the amount of irrigation and nitrogen application. Results depicted that a slight decrease in irrigation and an increase in N supply improved average root diameter, total root length, and root surface area, while the interaction was observed non-significant at average diameter of roots. Compared to the control, W80 N100 was statistically non-significant in photosynthesis and stomatal conductance. The W80 N100 resulted in a yield decrease of 2.90% and 8.75% but increased irrigation water use efficiency (IWUE) by 21.40% and 14.06%. Among interactions, the reduction in a single factor at W80 N100 and W100 N75 compensated the growth and yield. Hence, W80 N100 was found to be optimal regarding yield and IWUE, with 80% of irrigation water and 15 mM of N fertilization for soilless tomato production in greenhouses.

scholarly journals Analysis of Pore Water Pressure and Piping of Hydraulic Well

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 502
Author(s):  
Jinman Kim ◽  
Heuisoo Han ◽  
Yoonhwa Jin
Keyword(s):  
Numerical Analysis ◽  
Water Level ◽  
Pore Water ◽  
Large Scale ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Hydraulic Gradient ◽  
Water Levels ◽  
Seepage Velocity ◽  
Seepage Analysis

This paper shows the results of a field appliance study of the hydraulic well method to prevent embankment piping, which is proposed by the Japanese Matsuyama River National Highway Office. The large-scale embankment experiment and seepage analysis were conducted to examine the hydraulic well. The experimental procedure is focused on the pore water pressure. The water levels of the hydraulic well were compared with pore water pressure data, which were used to look over the seepage variations. Two different types of large-scale experiments were conducted according to the installation points of hydraulic wells. The seepage velocity results by the experiment were almost similar to those of the analyses. Further, the pore water pressure oriented from the water level variations in the hydraulic well showed similar patterns between the experiment and numerical analysis; however, deeper from the surface, the larger pore water pressure of the numerical analysis was calculated compared to the experimental values. In addition, the piping effect according to the water level and location of the hydraulic well was quantitatively examined for an embankment having a piping guide part. As a result of applying the hydraulic well to the point where piping occurred, the hydraulic well with a 1.0 m water level reduced the seepage velocity by up to 86%. This is because the difference in the water level between the riverside and the protected side is reduced, and it resulted in reducing the seepage pressure. As a result of the theoretical and numerical hydraulic gradient analysis according to the change in the water level of the hydraulic well, the hydraulic gradient decreased linearly according to the water level of the hydraulic well. From the results according to the location of the hydraulic well, installation of it at the point where piping occurred was found to be the most effective. A hydraulic well is a good device for preventing the piping of an embankment if it is installed at the piping point and the proper water level of the hydraulic well is applied.

scholarly journals Productivity of Ospreys, Pandion haliaetus, Affected by Water Levels Near Loon Lake, Saskatchewan, 1975-2002

2010 ◽  
Vol 124 (3) ◽  
pp. 219
Author(s):  
C. Stuart Houston ◽  
Frank Scott ◽  
Rob B. Tether
Keyword(s):  
Breeding Success ◽  
Water Levels ◽  
Lake Levels ◽  
The West ◽  
Canadian Data ◽  
Human Use ◽  
The Town ◽  
Western Half ◽  
Eastern Half

Between 1975 and 2002, diminished breeding success of Ospreys was associated with drought and falling lake levels in the western half of our study area near the town of Loon Lake, west-central Saskatchewan. Only 46% of nest attempts were successful in the west compared to 72% in the east, producing 0.88 young per accessible nest in the west and 1.42 in the east. Breeding success was greater in the eastern half, where water levels were stable, in spite of increased human use of the resort lakes there. Our unique long-term Canadian data base results support Ogden's 1977 prediction that Osprey productivity may decrease when water levels drop and fish populations are reduced.

scholarly journals Verification of greenhouse gas emission reductions: the prospect of atmospheric monitoring in polluted areas

2011 ◽  
Vol 369 (1943) ◽  
pp. 1906-1924 ◽  
Author(s):  
Ingeborg Levin ◽  
Samuel Hammer ◽  
Elke Eichelmann ◽  
Felix R. Vogel
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Catchment Area ◽  
Greenhouse Gas Emission ◽  
Atmospheric Transport ◽  
Atmospheric Measurements ◽  
Transport Modelling ◽  
Gas Emissions ◽  
Atmospheric Transport Modelling

Independent verification of greenhouse gas emissions reporting is a legal requirement of the Kyoto Protocol, which has not yet been fully accomplished. Here, we show that dedicated long-term atmospheric measurements of greenhouse gases, such as carbon dioxide (CO 2 ) and methane (CH 4 ), continuously conducted at polluted sites can provide the necessary tool for this undertaking. From our measurements at the semi-polluted Heidelberg site in the upper Rhine Valley, we find that in the catchment area CH 4 emissions decreased on average by 32±6% from the second half of the 1990s until the first half of the 2000s, but the observed long-term trend of emissions is considerably smaller than that previously reported for southwest Germany. In contrast, regional fossil fuel CO 2 levels, estimated from high-precision 14 CO 2 observations, do not show any significant decreasing trend since 1986, in agreement with the reported emissions for this region. In order to provide accurate verification, these regional measurements would best be accompanied by adequate atmospheric transport modelling as required to precisely determine the relevant catchment area of the measurements. Furthermore, reliable reconciliation of reported emissions will only be possible if these are known at high spatial resolution in the catchment area of the observations. This information should principally be available in all countries that regularly report their greenhouse gas emissions to the United Nations Framework Convention on Climate Change.

Long-term effect of cropping system and nitrogen and phosphorus fertilizer on production and nitrogen economy of grain crops in a Brown Chernozem

2005 ◽  
Vol 85 (1) ◽  
pp. 81-93 ◽  
Author(s):  
C. A. Campbell ◽  
R. P. Zentner ◽  
F. Selles ◽  
P. G. Jefferson ◽  
B. G. McConkey ◽  
...  
Keyword(s):  
Water Use ◽  
Environmental Sustainability ◽  
Crop Production ◽  
N Uptake ◽  
Yield Response ◽  
Average Response ◽  
Nitrogen And Phosphorus ◽  
N Yield ◽  
P Fertilizer

Assessment of the long-term impact of fertilizers and other management factors on crop production and environmental sustainability of cropping systems in the semi-arid Canadian prairies is needed. This paper discusses the long-term influence of N and P fertilizers on crop production, N uptake and water use of hard red spring wheat (Triticum aestivum L.), and the effect of the preceding crop type [flax (Linum usitatissimum L.) and fall rye (Secale cereale L.)] on wheat grown on a medium-textured, Orthic Brown Chernozem at Swift Current, Saskatchewan. We analysed 36 yr of results (1967–2002) from eight crop rotation-fertility treatments: viz., fallow-wheat receiving N and P (F-W, N + P), three F-W-W treatments fertilized with (i) N + P, (ii) P only, and (iii) N only; two other 3-yr mixed rotations with N + P (i) F-flax-W (F-Flx-W) and (ii) F-fall rye-W (F-Rye-W); and two continuous wheat rotations (Cont W), one receiving N + P and the other only P. Growing season weather conditions during the 36-yr period were near the long-term mean, but the first 22 yr were generally drier than normal while the last 14 yr (1989–2002) had average to above-average growing conditions. This was partly responsible for grain and N yield being greater in the latter period than in the first 22 yr. The 36-yr average response of wheat grown on fallow to P fertilizer was 339 kg ha-1, while the response to N fertilizer over this period was only 123 kg ha-1. The 36-yr average response of wheat grown on stubble to N was 344 kg ha-1 for F-W-(W) and 393 kg ha-1 for Cont W. Neither flax nor fall rye influenced the yield response of the following wheat crops. Annualized grain production for F-W (N + P), F-W-W (+ N) and F-W-W (+ P) rotations were similar (1130 kg ha-1 yr-1); this was about 15% lower than for F-W-W (N + P), 40% lower than for Cont W (N + P), and 5% lower than for Cont W (+ P). Annualized aboveground N yield for Cont W (N + P) was 57% higher than for Cont W (+ P). Regressions were developed relating straw to grain yields for wheat, flax and fall rye. The amount of NO3-N left in the soil was directly related to amount of N applied and inversely to N removed in the crop. Thus, F-(W)-W (+ N) left about 28% more NO3-N in the rooting zone than F-(W)-W (N + P), while F-W-(W) (N + P) left 20% more than F-W-(W) (+ P), and Cont W (N + P) left 39% more than Cont W (+ P). F-Rye-W (N + P) left much less NO3-N in the soil than any other fallow-containing system and similar amounts to Cont W (N + P). Key words: Yields, grain protein, N and P fertilizer, straw/grain regressions, water use, soil nitrate

Surface Cleaning Challenges for Organic Light Emitting Diodes

2021 ◽  
Vol 314 ◽  
pp. 3-8
Author(s):  
Noel Giebink
Keyword(s):  
Light Emitting Diodes ◽  
Surface Cleaning ◽  
Organic Light Emitting Diodes ◽  
Large Area ◽  
Light Emitting ◽  
Organic Light ◽  
Organic Optoelectronic Devices ◽  
Soft Thin Film ◽  
Organic Optoelectronic

Organic optoelectronic devices such as light-emitting diodes and solar cells present unique challenges for surface cleaning and preparation because of their large area and the ‘soft’, thin film nature of the materials involved. This paper gives an introduction to this class of semiconductor devices and covers a recent example of how surface cleaning impacts the long-term reliability of organic light-emitting diodes being commercialized for solid-state lighting.

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