scholarly journals Evaluating the Effect of Absolute and Barometric Pressures on Borehole Performance in Tolon and Wa West Districts of Northern Ghana

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
A-G Shaibu ◽  
H. Ishikawa
Keyword(s):  
Water Level ◽  
Water Table ◽  
Water Pressure ◽  
Barometric Pressure ◽  
Northern Ghana ◽  
Annual Rainfall ◽  
Rainfall Regime ◽  
Rainfall Variation ◽  
Granitoid Intrusions ◽  
The Relationship

Groundwater is a very important asset to the people of Northern Ghana where majority are farmers as its used for many domestic and agricultural activities. The research evaluated the effects of absolute and barometric pressures on water-table fluctuations of boreholes in Wa West and Tolon Districts of Northern Ghana. Pumping tests, absolute and barometric pressures were monitored using non-vented water level sensors for one year, from 2015-2016. The results of the research indicate that, the aquifer of the Kpaligung borehole is of Voltaian province while that of Baleofili is Granitoid intrusions. The yield of the Baleofili borehole is 1.8 m3/h (30 l/min), while that of the Kpaligung borehole yields 1.4 m3/h (23 l/min). Rainfall regime has considerable effects on Kpaligung and Baleofili boreholes` recharge and water-table fluctuation due to the effects of both absolute and barometric pressure throughout the year. The relationship between barometric pressure and water pressure for the Kpaligung borehole shows positive, but weak correlation value (0.2) that is, increase in barometric pressure leads to an increase in water level and vice versa. The Baleofili borehole shows an inverse relationship between barometric pressure and water level pressure with the coefficient of correlation being 0.5. The relationship between the changes in water level of the boreholes with the corresponding change in rainfall amount suggests that the groundwater recharge of the boreholes depends considerably on annual rainfall variation in the study areas considered.

scholarly journals Statistical analysis of rainfall and streamflow time series in the Lake Tana Basin, Ethiopia

2018 ◽  
Vol 11 (1) ◽  
pp. 258-273 ◽  
Author(s):  
Tibebe B. Tigabu ◽  
Georg Hörmann ◽  
Paul D. Wagner ◽  
Nicola Fohrer
Keyword(s):  
Time Series ◽  
Water Level ◽  
Lake Water ◽  
Land Use Changes ◽  
Annual Rainfall ◽  
Lake Tana ◽  
Agricultural Water Management ◽  
Lake Water Level ◽  
Rainfall Variation ◽  
Sample Data

Abstract This research focuses on the statistical analyses of hydrometeorological time series in the basin of Lake Tana, the largest freshwater lake in Ethiopia. We used autocorrelation, cross-correlation, Mann–Kendall, and Tukey multiple mean comparison tests to understand the spatiotemporal variation of the hydrometeorological data in the period from 1960 to 2015. Our results show that mean annual streamflow and the lake water level are varying significantly from decade to decade, whereas the mean annual rainfall variation is not significant. The decadal mean of the lake outflow and the lake water level decreased between the 1990s and 2000s by 11.34 m3/s and 0.35 m, respectively. The autocorrelation for both rainfall and streamflow were significantly different from zero, indicating that the sample data are non-random. Changes in streamflow and lake water level are linked to land use changes. Improvements in agricultural water management could contribute to mitigate the decreasing trends.

Dewatering Preloading Test and Ground Subsidence in a Project

2011 ◽  
Vol 250-253 ◽  
pp. 1912-1916
Author(s):  
Yong Mou Zhang ◽  
Jian Chang Zhao
Keyword(s):  
Water Level ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
New Technology ◽  
Soft Soil ◽  
Soil Treatment ◽  
Ground Subsidence ◽  
Confined Water ◽  
Phreatic Water ◽  
The Relationship

Ground subsidence is one of the main geological hazards in Shanghai. The ground subsidence is caused by pumping groundwater greatly. In the past, studies of ground subsidence in Shanghai were mostly taken for the ground subsidence caused by pumping confined water in Puxi. And ground subsidence caused by pumping phreatic water was rarely studied. Dewatering preloading is a new technology for soft soil treatment. The monitoring of ground water level, ground subsidence, pore water pressure in the process of dewatering preloading test for a soft soil treatment project in Pudong showed that pumping phreatic water can also cause ground subsidence. The ground subsidence caused by pumping phreatic water was analyzed in this paper. The relationship between phreatic water level and ground subsidence was obtained.

scholarly journals Observation of Basal Sliding of Variegated Glacier, Alaska

1979 ◽  
Vol 23 (89) ◽  
pp. 406-407 ◽  
Author(s):  
H. Engelhardt ◽  
B. Kamb ◽  
C. F. Raymond ◽  
W. D. Harrison
Keyword(s):  
Water Level ◽  
Water Table ◽  
Water Pressure ◽  
Water System ◽  
High Water ◽  
Surface Velocity ◽  
Mountain Range ◽  
Hole Wall ◽  
Exponential Trend ◽  
Internal Deformation

Abstract Variegated Glacier is a surge-type glacier in the St Elias mountain range in Alaska. The interval between surges is about 20 years; the last one occurred in 1964 to 1965. This glacier has been studied extensively since 1973 (Bindschadler and others, 1977). Thus far, measurements of ice velocities have been restricted to the surface. They have been analyzed using geophysically measured ice depths, in order to estimate ice velocities in the ice mass and at the base (Bindschadler and others, 1978). From 1973 to 1977 the distribution of annual ice velocities along most of the length of the glacier can be explained primarily by internal deformation without major contribution from sliding at the base. However, the variation of surface velocity with time gives definite indication that sliding occurs in summer and that the average summer rate is increasing progressively from summer to summer and that in a zone 5 to 7 km below the head of the glacier the summer-to-summer increase in inferred sliding rate is especially rapid. This is a notably distinguishing feature, which is probably indicative of a build-up toward the next surge. In order to obtain direct information about sliding-rates and water pressures at the base in this zone, a bore hole was drilled to the bottom of the glacier about 6 km below the glacier head. Observations in the hole started in June 1978 and were continued until 31 July 1978. The hole connected to an englacial water system at a depth of 204 m whereupon the water level dropped gradually to about 100 m below the surface. The last 6 m above-the base at 356 m could be drilled only by means of a cable tool because of the presence of debris-rich ice. Upon reaching the bottom, the water level increased rapidly to the firn water table at about 8 m below surface. Large variations in water level of about 200 m occurred during the following period of observation of 35 d. Major events such as audible icequakes, heavy rainfalls, and a period of unusually high ablation were associated with abrupt increases of water level up to the firn water table. High water pressure at the bottom drove a flow of muddy and sandy water upward in the hole. Consequently high freezing rates in the lower 150 m of the hole produced a very rough bore-hole wall covered with ledges, coral-reef-like features, grooves, and pockets filled with sand. Near the bottom, embedded rocks stuck out of the bore-hole wall. These features were recognized by bore-hole television. The bore-hole bottom consisted of sand which continuously proliferated and washed into the hole. Attempts to remove this sand by means of a sand pump failed, the bailed-out sand being replaced immediately. From bore-hole inclinometry an internal deformation of the ice mass of 0.22 m d−1 was obtained. Together with average surface velocity of 0.47 m d−1 we get a sliding velocity of 0.25 m d−1, averaged over the time of observation. This result confirms the sliding velocities inferred from surface velocity measurements. It also lies on the exponential trend line of increasing summer-to-summer velocities showing a doubling of sliding velocities about every two years (Bindschadler and others, unpublished). This strongly indicates that the next surge is likely to occur in the early eighties. Input of water from the surface probably will play a role in triggering the surge.

scholarly journals The rainfall regime and its uncertainty in Valencia and Larnaca

2007 ◽  
Vol 12 ◽  
pp. 101-106 ◽  
Author(s):  
H. Reiser ◽  
H. Kutiel
Keyword(s):  
Mediterranean Climate ◽  
Annual Rainfall ◽  
Rainfall Regime ◽  
Season Length ◽  
Dry Spell ◽  
The Mediterranean ◽  
Definition Of ◽  
The Relationship ◽  
Two Sides ◽  
The Mediterranean Basin

Abstract. The Most Expected Rainfall Regime – MERR in a certain region is composed of various parameters regarding the annual rainfall regime in that region. The present study examines several parameters of the MERR, such as: the rainfall TOTAL, the Date of Accumulated Percentage-DAP, the Rainy Season Length-RSL, the Number of Rain-Spells-NRS, the Rain-Spell Yield-RSY, the ratio between Average and Median rainfall-AMED, the relationship between accumulated precipitation and the number of rain-spells and the Dry-Spell Distribution-DSD. Two stations at the two sides of the Mediterranean basin, Valencia and Larnaca, have been used to illustrate the distribution of the above parameters across the Mediterranean. The main conclusion of the study is that the rainfall regime at Larnaca is less uncertain as compared with the regime in Valencia. This is probably due to the fact that rainfalls are completely absent during the summer in Larnaca, which better suits the definition of a Mediterranean climate than that of Valencia.

scholarly journals Long-Term Study of the Relationship between Precipitation and Aquatic Vegetation Succession in East Taihu Lake, China

Scientifica ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Yehui Zhang ◽  
Na Yang ◽  
Jiawei Xu ◽  
Yixing Yin
Keyword(s):  
Water Level ◽  
Aquatic Plants ◽  
Aquatic Vegetation ◽  
Taihu Lake ◽  
Vegetation Succession ◽  
Annual Rainfall ◽  
Dry Period ◽  
Long Term Study ◽  
The Relationship

Based on long-term rainfall measurements (1956–2012), water level records (1956–2006), and aquatic plants field survey data (1960–2014), the relationship between precipitation and aquatic vegetation succession in east Taihu Lake, China, is studied. Neither abrupt changes nor any trends were found in the annual rainfall series in Taihu Lake during the studied period (1956–2012). However, for seasonal variations, statistically significant decreases are found in spring and autumn, while the rainfall in winter exhibits statistically significant increase. No significant trend was obtained in summer. A “dry” period was detected in our studied period (1963/1964~1978/1979). Total annual rainfall was significantly positively correlated to the number of rain-days (r=0.59) and the water level (r=0.84). Our results indicate that the variations of rainfall and water level may have an impact on the aquatic plants in Taihu Lake. The dry period may be not suitable for the growth of the aquatic plants. All aquatic plants in Taihu Lake were dramatically reduced in the dry period, especially for submerged macrophytes and floating-leaf macrophytes. Our results may be helpful for the aquatic restoration in the future.

Properties of deep sandy soils and the growth of Lovegrass, Eragrostis curvula (Schrad.) Nees

Soil Research ◽  
1970 ◽  
Vol 8 (2) ◽  
pp. 123 ◽  
Author(s):  
P Farrington ◽  
NA Campbell
Keyword(s):  
Water Table ◽  
Sandy Soils ◽  
Clay Content ◽  
Coarse Sand ◽  
Annual Rainfall ◽  
Sand Content ◽  
Moisture Supply ◽  
Close Relationship ◽  
Site Variation ◽  
The Relationship

The relationships between soil properties and the annual yield of lovegrass were studied on deep sandy soils near Meckering, Western Australia. Mean annual rainfall of the area is 378 mm, most of which falls between May and September. At sites with a water table a close relationship was established between annual yield and two properties-the depth to a water table, and the silt and clay content in the 30-60 cm layer. The relationship accounted for at least 87% of the between-site variation in yield, and was maintained between years, and over a range of nutrition levels. At sites without a water table, yield was closely related to soil mechanical composition. Where the coarse sand content in the profile exceeded 70%, survival of the grass was poor. The importance of soil moisture supply to growth of the grass in these soils is discussed, and the success of the 'edaphic' trial technique is briefly assessed.

scholarly journals Observation of Basal Sliding of Variegated Glacier, Alaska

1979 ◽  
Vol 23 (89) ◽  
pp. 406-407 ◽  
Author(s):  
H. Engelhardt ◽  
B. Kamb ◽  
C. F. Raymond ◽  
W. D. Harrison
Keyword(s):  
Water Level ◽  
Water Table ◽  
Water Pressure ◽  
Water System ◽  
High Water ◽  
Surface Velocity ◽  
Mountain Range ◽  
Hole Wall ◽  
Exponential Trend ◽  
Internal Deformation

AbstractVariegated Glacier is a surge-type glacier in the St Elias mountain range in Alaska. The interval between surges is about 20 years; the last one occurred in 1964 to 1965. This glacier has been studied extensively since 1973 (Bindschadler and others, 1977). Thus far, measurements of ice velocities have been restricted to the surface. They have been analyzed using geophysically measured ice depths, in order to estimate ice velocities in the ice mass and at the base (Bindschadler and others, 1978). From 1973 to 1977 the distribution of annual ice velocities along most of the length of the glacier can be explained primarily by internal deformation without major contribution from sliding at the base. However, the variation of surface velocity with time gives definite indication that sliding occurs in summer and that the average summer rate is increasing progressively from summer to summer and that in a zone 5 to 7 km below the head of the glacier the summer-to-summer increase in inferred sliding rate is especially rapid. This is a notably distinguishing feature, which is probably indicative of a build-up toward the next surge. In order to obtain direct information about sliding-rates and water pressures at the base in this zone, a bore hole was drilled to the bottom of the glacier about 6 km below the glacier head. Observations in the hole started in June 1978 and were continued until 31 July 1978. The hole connected to an englacial water system at a depth of 204 m whereupon the water level dropped gradually to about 100 m below the surface. The last 6 m above-the base at 356 m could be drilled only by means of a cable tool because of the presence of debris-rich ice. Upon reaching the bottom, the water level increased rapidly to the firn water table at about 8 m below surface. Large variations in water level of about 200 m occurred during the following period of observation of 35 d. Major events such as audible icequakes, heavy rainfalls, and a period of unusually high ablation were associated with abrupt increases of water level up to the firn water table. High water pressure at the bottom drove a flow of muddy and sandy water upward in the hole. Consequently high freezing rates in the lower 150 m of the hole produced a very rough bore-hole wall covered with ledges, coral-reef-like features, grooves, and pockets filled with sand. Near the bottom, embedded rocks stuck out of the bore-hole wall. These features were recognized by bore-hole television. The bore-hole bottom consisted of sand which continuously proliferated and washed into the hole. Attempts to remove this sand by means of a sand pump failed, the bailed-out sand being replaced immediately. From bore-hole inclinometry an internal deformation of the ice mass of 0.22 m d−1 was obtained. Together with average surface velocity of 0.47 m d−1 we get a sliding velocity of 0.25 m d−1, averaged over the time of observation. This result confirms the sliding velocities inferred from surface velocity measurements. It also lies on the exponential trend line of increasing summer-to-summer velocities showing a doubling of sliding velocities about every two years (Bindschadler and others, unpublished). This strongly indicates that the next surge is likely to occur in the early eighties. Input of water from the surface probably will play a role in triggering the surge.

scholarly journals Rainfall Governs Pecan Stand Homogeneity in Native, Wild Habitats

2002 ◽  
Vol 127 (5) ◽  
pp. 860-868 ◽  
Author(s):  
Darrell Sparks
Keyword(s):  
Soil Texture ◽  
Tree Species ◽  
Sympatric Species ◽  
Carya Illinoinensis ◽  
Annual Rainfall ◽  
Strongly Correlated ◽  
Rainfall Variation ◽  
Native Habitat ◽  
Growth Partitioning ◽  
The Relationship

The relationship was analyzed between historical annual rainfall and pecan [Carya illinoinensis (Wangenh.) K. Koch] homogeneity in selected hardwood populations along two river systems in the native habitat of the species. Tree species other than pecan (sympatric species) were more abundant with increasing rainfall in that the more homogenous pecan populations were located in geographic areas with the least rainfall. These results are the first to establish that pecan stand homogeneity across geographic areas is inversely related to the amount of annual rainfall. Variation in soil texture within geographic areas was also strongly correlated with variation in pecan homogeneity and pecan density. Pecans occur principally on loamy bottom lands and grow on clayey bottom lands in less abundance. A hypothesis related to growth partitioning between root and shoot is proposed to account for pecan's survival advantage, and thus higher stand homogeneity, with decreasing rainfall in native pecan areas. Conversely, the decrease in stand homogeneity with increasing rainfall is proposed to be due to increased forestation of sympatric species on clayey sites that are not optimum for pecan. Across the rainfall gradients, pecan's shade intolerance is suggested to be minimized by differential site requirements for pecan and its sympatric species.

Impact of changing rainfall conditions on surface and groundwater resources in an experimental watershed in Greece

2013 ◽  
Vol 12 (2) ◽  
pp. 119-125
Keyword(s):  
Groundwater Resources ◽  
Annual Runoff ◽  
Annual Rainfall ◽  
Rainfall Regime ◽  
Winter Rainfall ◽  
Rainfall Depth ◽  
Rainfall Volume ◽  
The Mean ◽  
Groundwater Reserves ◽  
The Impact

The present study concerns the impact of a change in the rainfall regime on surface and groundwater resources in an experimental watershed. The research is conducted in a gauged mountainous watershed (15.18 km2) that is located on the eastern side of Penteli Mountain, in the prefecture of Attica, Greece and the study period concerns the years from 2003 to 2008. The decrease in the annual rainfall depth during the last two hydrological years 2006-2007, 2007-2008 is 10% and 35%, respectively, in relation to the average of the previous years. In addition, the monthly distribution of rainfall is characterized by a distinct decrease in winter rainfall volume. The field measurements show that this change in rainfall conditions has a direct impact on the surface runoff of the watershed, as well as on the groundwater reserves. The mean annual runoff in the last two hydrological years has decreased by 56% and 75% in relation to the average of the previous years. Moreover, the groundwater level follows a declining trend and has dropped significantly in the last two years.

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