Neural network prediction of nitrate in groundwater of Harran Plain, Turkey
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Wells screened across multiple aquifers can provide pathways for the movement of surprisingly large volumes of groundwater to confined aquifers used for public water supply (PWS). Using a simple numerical model, we examine the impact of several pumping scenarios on leakage from an unconfined aquifer to a confined aquifer and conclude that a single inactive multi-aquifer well can contribute nearly 10% of total PWS well flow over a wide range of pumping rates. This leakage can occur even when the multi-aquifer well is more than a kilometer from the PWS well. The contribution from multi-aquifer wells may be greater under conditions where seasonal pumping (e.g., irrigation) creates large, widespread downward hydraulic gradients between aquifers. Under those conditions, water can continue to leak down a multi-aquifer well from an unconfined aquifer to a confined aquifer even when those multi-aquifer wells are actively pumped. An important implication is that, if an unconfined aquifer is contaminated, multi-aquifer wells can increase the vulnerability of a confined-aquifer PWS well.
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A pot experiment of rape was conducted to investigate the effect of water on nitrate and nitrite concentration of rape after picking with three irrigation level of 100%, 75% and 50% field capacity. Results showed that nitrate and nitrite concentration of rape were affected by irrigation level and storage time. During the period of eight days after picking, the nitrate concentration of rape in the irrigation treatment of 0.50θf irrigation level was the highest in all the irrigation treatment .While the nitrate concentration of rape in the irrigation treatment of 1.00θf irrigation level was the lowest on the picking day. The nitrate concentration of rape in the irrigation treatment of 0.75θf irrigation level was higher than that at 1.00θf irrigation level on the picking day , but decreased to the lowest in all the irrigation treatment after the picking day. The nitrite concentration of rape was the lowest in the irrigation treatment of 1.00θf irrigation level in all the irrigation treatment on the picking day .The concentration of nitrate and nitrite decreased, then increased and fell again after picking in all the irrigation treatment. It is concluded that the irrigation level of 1.00θf and made the rape been eaten in one or two days after picked up, had an advantage in reducing the nitrate and nitrite concentration of rape and should be applied in the cultivation of rape.
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In southwest Florida, principal hydrogeologic units include the surficial aquifer system, the intermediate aquifer system, and the Floridan aquifer system. The Floridan aquifer system consists of the Upper and Lower Floridan aquifers separated by a middle confining unit. The intermediate aquifer system includes all water-bearing units and confining units between the overlying surficial aquifer system and the underlying Floridan aquifer system. Thickness of the surficial aquifer system ranges from 25 to 250 ft and thickness of the intermediate aquifer system ranges from less than 100 to more than 800 ft. Transmissivity of the intermediate aquifer system ranges from less than 200 to about 12,000 sq ft/day. In the northern part of the study area, the potentiometric surface of the intermediate aquifer system is higher than the potentiometric surface of the underlying Upper Floridan aquifer. Water is transmitted downward through the confining unit and recharges the Upper Floridan aquifer. The gradient in head reverses in the southern part of the study area. In 1985, an estimated 808 million gal/day of freshwater was withdrawn from all aquifers in the study area for irrigation, public and rural supply, and industrial use. Of this total, an estimated 68.9 million gal/day was withdrawn from the intermediate aquifer system. (USGS)
Surficial aquifer
Cone of depression
Aquifer test
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Water levels in 722 wells in the Coastal Plain of New Jersey, Pennsylvania, and northeastern Delaware were measured during October and November 1993 and were used to define the potentiometric surface of the eight major confined aquifers of the area. Isochlors (lines of equal chloride concentration) for 250 and 10,000 milligrams per liter are included to show the extent of freshwater in each of the aquifers. Estimated water withdrawals from the eight major confined aquifers are reported for 1978-94. Water-withdrawal and water-level maps including isochlors were constructed for the Cohansey aquifer of Cape May County, the Atlantic City 800-foot sand, the Piney Point aquifer, the Wenonah-Mount Laurel aquifer, the Englishtown aquifer system, the Upper Potomac-Raritan-Magothy, the Middle and undifferentiated Potomac-Raritan-Magothy, and the Lower Potomac-Raritan-Magothy aquifers. From 1988 to 1993, water levels near the center of the large cones of depression in the Middlesex-Monmouth County area rose as much as 120 ft in the Wenonah-Mount Laurel aquifer and Englishtown aquifer system, 40 ft in the Upper Potomac-Raritan-Magothy aquifer, and 96 ft in the Middle and undifferentiated Potomac-Raritan-Magothy aquifers. Large cones of depression in the potentiometric surface of aquifers of the Potomac-Raritan-Magothy aquifer system in the Burlington-Camden-Gloucester area remained at about the same altitude; that is, the potentiometric surface neither rose nor fell in the aquifers by more than 5 feet. In the same area, water levels in the Englishtown aquifer system were static, whereas the water levels in the Wenonah-Mount Laurel aquifer declined 5 to 20 feet, forming an expanded cone of depression. Water levels in the Cohansey, Atlantic City 800-foot sand, and Piney Point aquifers declined by 1 to 10 feet during 1988?93.
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The buried‐valley aquifers that are common in the glacial deposits of the northern hemisphere are a typical case of the strip aquifers that occur in many parts of the world. Pumping from a narrow strip aquifer leads to much greater drawdown and much more distant drawdown effects then would occur in a sheet aquifer with a similar transmissivity and storage coefficient. Widely used theories for radial flow to wells, such as the Theis equation, are not appropriate for narrow strip aquifers. Previously published theory for flow to wells in semiconfined strip aquifers is reviewed and a practical format of the type curves for pumping‐test analysis is described. The drawdown response of strip aquifers to pumping tests is distinctive, especially for observation wells near the pumped well. A case study is presented, based on extensive pumping test experience for the Estevan Valley Aquifer in southern Saskatchewan, Canada. Evaluation of groundwater resources in such buried‐valley aquifers needs to take into account the unusually large drawdowns in response to pumping.
Drawdown (hydrology)
Aquifer test
Aquifer properties
Water well
Surficial aquifer
Cone of depression
Slug test
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Aquifer test
Natural gas field
Specific storage
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Vulnerability index
Surficial aquifer
Specific storage
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This report delineates and describes the geohydrology and susceptibility of the major aquifers to contamination in Area 1 - Colbert, Franklin, Lauderdale, Lawrence, Limeston, Madison, and Morgan Counties. Most of the area is underlain by a Mississippian carbonate sequence that includes two major aquifers, the Tuscumbia-Fort Payne aquifer and the Bangor aquifer. A third major aquifer, the Tuscaloosa aquifer of Cretaceous age, occurs in the southwest part of the area. The Mississippi carbonate aquifers are the Tuscumbia-Fort Payne aquifer which includes most Tuscumbia Limestone and the Fort Payne Chert, and a small area of the Monteagle Limestone, and the Bangor aquifer which includes the Bangor Limestone and Hartselle Sandstone. Both of these aquifers possess highly-variable secondary porosity and permeability related to fractures that have been enlarged, sometimes to cavernous proportions, due to solution processes. The Tuscaloosa aquifer consists of the Tuscaloosa Group, an unconsolidated clastic deposit that has relatively uniform primary porosity and permeability. Significant quantities of groundwater are available from each of the aquifers. Water levels at nearly 2 ,000 wells indicate that, for each aquifer, general groundwater movement is from topographically high to low areas. Each of the aquifers is recharged throughout its outcrop in the study area and is susceptible to contamination within the outcrop. Generalized topographic settings such as closed-contour depressions are identified as areas that are highly susceptible to contamination. Specific features such as sinkholes also are identified as extremely susceptible to contamination.
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Based on the water level data of different deep aquifers recorded by automatic water gauge in the pumping test,the hydraulic connection between pumping aquifer and nonpumping aquifer in the early pumping stage was analyzed in this paper.The results show that(1) the water levels in nonpumping aquifers were affected as the target aquifer was pumping,and in the early pumping stage,the effect was large,then the effect disappeared as the water level in the target pumping aquifer was stable or slowly down;(2)the further the distance between the target pumping aquifer and the nonpumping aquifer,the less effect to the water levels in nonpumping aquifers;(3)the water level effect in multi-aquifer test was related to the parameters α,β,n and Cm according to the numerical simulation of groundwater flow and the stress change principle.
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Specific storage
Cone of depression
Slug test
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