Therefore, C may be determined by C = (s/Q n -s/Q n-1 )/(Q n -Q n-1 ). When the drawdown data is plotted this way, each step plots as a straight on a semi-log graph, and the y-intercept for each step differs from the preceding step by (Q n -Q n-1 )C. Hypothetical pumping well adjusted time versus adjusted drawdown with well loss. The extra drawdown for the hypothetical well is shown (red) in Figure 3.įigure 4. If a term CQ 2 is added to equation 1 and C is given a hypothetical value of 0.002 (ft min 2 /gal 2 ), which is a relatively high value. Rorabaugh ( 1 953 ) applied a graphical procedure and concluded that the exponent y "may be unity at very low rates of discharge, or it may be in excess of 2." He recognized that CQ y, where y is not equal to 2, might more accurately reflect well loss, and higher precision might warrant determination of of the exponent y by trial and error or by a graphical procedure. Jacob represented "well loss" as CQ 2, where C is an empirical coefficient. The second component is termed "well loss" and represents various effects on drawdown in the well, such as turbulent flow in and near the well, clogging near the well, head loss through a well screen, and losses in an artificial sand or gravel filter in the annulus around a well screen. One component is drawdown proportional to discharge, and the second component is drawdown proportional to approximately the square of the discharge. Jacob (1947) stated that drawdown in a pumping well has two components. The benefits for the participants are therefore immense.CONVENTIONAL WATER Well STEP TEST WITH WELL LOSS This training will provide an excellent opportunity for hands-on real life technical training on how to properly conduct a borehole sustainable yield test, data collection, processing and analysis to estimate the yield. The facilitator will then take the participants through processing and analysis of the data to understand flow characteristics and estimate the borehole sustainable yield. From theory, practical aquifer pumping test will be conducted by the participants with the guidance of the facilitator. The components of this training are therefore designed to cover the theoretical aspects of borehole sustainable yield testing and analysis of data to estimate the yield. To estimate borehole sustainable yield, an appropriate aquifer pumping test should be conducted and the data should be analysed using appropriate methods taking into considerations the capacity of the aquifer system and groundwater needs among other factors. The estimation of borehole sustainable yield is based on the principles of aquifer pumping tests. In South Africa, the term sustainable yield is typically used. This borehole yield is sometimes referred as the safe yield or reliable yield. Sustainable Groundwater & Drought ManagementĪnyone who owns a borehole is interested in knowing the maximum discharge rate at which they can abstract/pump groundwater in such a way that they can be assured of continuously getting that yield from their borehole. GDE’s and and Biodiversity – Khakea/Bray Transboundary Aquifer.Eastern Kalahari Karoo Basin Acquifer System.Business Strategy & Financial Sustainability Plans.GMI Policy Legal and Institutional Project.PLI & Gender Equality and Social Inclusion.Groundwater Information Portal Enhancement.GDE’s & Biodiversity in the Khakea/Bray Transboundary Aquifer.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |