A simple method for determining specific yield from pumping tests by L. E. Ramsahoye Download PDF EPUB FB2
A SIMPLE METHOD FOR DETERMINING SPECIFIC YIELD FROM PUMPING TESTS By L. RAMSAHOYE and S. LANG ABSTRACT A simpler solution which greatly reduces the time necessary to compute the specific yield by the pumping-test method of Remson and Lang () is presented.
The method consists of computing the volume of dewatered material in the cone of Cited by: 8. A simpler solution which greatly reduces the time necessary to compute the specific yield by the pumping-test method of Remson and Lang () is presented.
The method consists of computing the volume of dewatered material in the cone of depression and comparing it with the total volume of discharged water. The original method entails the use of a slowly converging series to compute the.
A SIMPLE METHOD FOR DETERMINING SPECIFIC YIELD FROM PUMPING TESTS, GROUND-WATER HYDRALICS [L.E.& Lang, S.M. Ramsahoye] on. Specific yield, applicable for The objectives of the pumping test are to determine well yie Introduction The basic concept of a pumping test is very simple water is removed by pumping Author: A.
Balasubramanian. SPECIFIC YIELD COMPILATION OF SPECIFIC YIELDS FOR VARIOUS MATERIALS By A. JOHNSON ABSTRACT Specific yield is defined as the ratio of (1) the volume of water that a srturated rock or soil will yield by gravity to (2) the total volume of the rock or soil.
Specific yield is usually expressed as a by: The principle of a pumping test is that if we pump water from a well and measure the discharge of the well and the drawdown in the well and in piezometers at known distances from the well, we can substitute these measurements into an appropriate well-flow equation and can calculate the hydraulic characteristics of the aquifer (Fig- ure ).
the well driller. Well yield tests are done using bailing1, air liftingor similar methods. Well yield tests are not as reliable as a pumping test in the following situations: Μ when well capacity is low (e.g., typical bedrock well); Μ when the maximum yield from the well is required; Μ when reliable estimates of aquifer properties are needed.
pumping test data analysis which at present are exten sively used in analysis of problems involving Illinois wells. These methods are, the non-equilibrium "type curve" method, the modified non-equilibrium "straight line" method, the step-drawdown analysis developed.
The Specific yield is dimensionless or can be given in %. 18 Specific capacity of a well: It is the ratio of discharge of the well to the drawdown, in m3 /hour/m. The objectives of the pumping test are to determine well yield, determine well efficiency, determine aquifer parameters and to examine water chemistry.
Navigation: Pumping Test: Theory and Analysis Methods > Pumping Test Analysis Methods - Fixed Assumptions > Theis Recovery Test (confined) When the pump is shut down after a pumping test, the water level inside the pumping and observation wells will start to rise. This rise in water level is known as residual drawdown (s').
Methods of Pumping Test Specific Yield (Sy) is the volume of water yield by gravity drainage to the volume of the aquifer. The specific yield is dimensionless and typically ranges from to Duration of pumping test It’s difficult to determine how many hours that.
the test, available drawdown, specific capacity, method of water level measurements and water levels/times recorded Well 2yield tests are done using bailing1 or air lifting methods.
Well yield tests are not as reliable as a pumping test in the will design the pumping test and determine whether sentinel or observation wells (monitoring. Common types of pumping tests that you may perform include the following.
Constant-rate tests maintain pumping at the control well at a constant rate. This is the most commonly used pumping test method for obtaining estimates of aquifer properties.
Step-drawdown tests proceed through a sequence of constant-rate steps at the control well to determine well performance. All the other methods, however, are so complex that one needs a computer to apply them.
We have also updated the book in the light of developments that have taken place since the first edition appeared some twenty years ago. We present, for instance, a more modern method of analyzing pumping tests in unconfined aquifers with delayed yield.
[1/L] Specific Yield (Sy)Specific Yield (Sy) is the volume of water yieldis the volume of water yield by gravity drainage to the volume of theby gravity drainage to the volume of the aquifer. The specific yield is dimensionlessaquifer. The specific yield is dimensionless and typically ranges from to and typically ranges from to Neuman developed a solution method for pumping tests performed in unconfined aquifers, which can be used for both fully or partially penetrating wells.
When analyzing pumping test data from unconfined aquifers, one often finds that the drawdown response fails to follow the classical Theis () solution. determine if the yield of a well has been adversely affected. There also needs to be a method by which the yield of the replacement well can be compared to the pre-mining well yield rate to determine if the replacement supply is equivalent (30 CFR § ).
Conventional pumping and slug tests cannot be used, because they are designed to. A yield test involves a test to see the balance between the maximum amount of water that can be pumped out of the borehole and the amount of water that recharges back from the surrounding ground water source.
There are a number of aspects that need to be taken into consideration when testing a borehole. There are two important rules that need.
Pumping Test. Pumping tests used for field estimation of the hydraulic conductivity sample the flow on a much larger volume of aquifer material than in a laboratory, thus providing an averaging parameter such as K, which is estimated at a much larger scale than the scale of a laboratory test (Dagan, ).
pumping: the so-called safe yield for 20 years of continuous pumping (Q20 or Q20). In the past there have been doubts expressed about the procedure used and its physical validity.
WDA was asked to apply this method in determining the available groundwater supply in a rural area of Southern Alberta.
When examining the history of the year. Determine if the test will be conducted for 72 hours or 10 days. If the test is conducted for 72 hours, 25% of the test pumping rate will be granted. If the test is conducted for 10 days, 50% of the test pumping rate will be granted.
Ensure discharge from the pump is piped far enough away to avoid recharge. Conducting the testing. Aquifer tests (pumping tests, slug tests and constant-head tests) are performed to estimate site-specific values for the hydraulic properties of aquifers and aquitards.
Under certain circumstances, however, site-specific hydraulic property data may not be available when needed. For example, reconnaissance studies or scoping calculations may require hydraulic property values. Well yield is the volume of water per unit of time that is produced from the well by pumping.
Usually, well yield is measured in terms of gallons per minute (gpm) or gallons per hour (gph). Sometimes, large flows are measured in cubic feet per second (cfs) Specific capacity Specific capacity is expressed as the well yield per unit of drawdown.
test software (FC Method) to determine the sustainable yield of the boreholes. The results of the pump tests are summarised in Table 2 below, whilst the plotted pump test data and borehole management recommendation sheets are contained in Appendix B.
Table 2: Summarised Yield Test Data BH No. BH Depth (m bgl) SWL* (m bgl) Pump Installation Depth. several methods for determining approximate yield (such as the bailer method or the air lift method), only the pump method is an acceptable testing method according to the Wells Regulation.
Only a pump, such as a submersible, jet or shallow lift pump with appropriate control devices and. Single-well aquifer tests provide data in many situations in which aquifer pumping-test data from multiple wells would be a luxury for the ground-water analyst.
The primary factor limiting the performance of multi-well aquifer tests is cost, particularly in areas with large depth to water (Belcher et al, ). Limiting analysis to existing.
The answers to these questions can only come through properly designed testing of the well. Testing should include a pumping test, sometimes referred to as an aquifer test, to determine the yield or flow of the well, and water quality tests that determine whether or not harmful bacteria or chemical contaminants are present.
CONTROLLED PUMPING TEST REV. #: SCOPE AND APPLICATION The most reliable and commonly used method of determining aquifer characteristics is by controlled aquifer pumping tests. Groundwater flow varies in space and time and depends on the hydraulic properties of the rocks and the boundary conditions imposed on the groundwater system.
How to Calculate Well Yield if We Run Out of Water During a Simple Flow Test. Calculate how many gallons of water you ran by adding up the individual fixture flow rates in gpm; multiply each fixture flow rate by the time it was running, and add up these numbers to.
A manual pumping test method is presented, which at a fraction of the cost of a conventional pumping test, measures the specific capacity of rope-pump wells. The method requires only sight modifcations to the well and reasonable limitations on well useage prior to testing.
The pumping test was performed a minimum of 33 times in three wells over an. pumping test to determine the test well’s sustainable yield. Measurement of pumping rate must be carried out in accordance with Section 6.b.
3. LENGTH OF TEST – Regardless of the type of aquifer, pumping tests shall be conducted for a minimum of 72 hours at a constant pumping rate.
The following points must be addressed. a. Engrs., 3, part 3 (August ) 3) N. S. Boulton, Analysis of data from non-equilibrium pumping tests allowing for delayed yield from storage.
Proc. Instn. Civ. Engrs., 26 (November ) Discussion, 28 (August ) 4) G. Dagan, A method of determining the permeability and effective porosity of un- confined anisotropic.It is a short-term test that can be used to determine: 1) a pumping rate for a constant-rate test, 2) specific capacity (defined as the ratio of the production rate or yield of a well to the drawdown required to produce that yield), and 3) well efficiency.