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Abstract

Determination of Hydraulic Conductivity Using Analytical and Numerical Methods Applied to Well and Aquifer Tests This study aims to determine the hydraulic conductivity of aquifers by analytical and numerical methods applied to water level data obtained from well and aquifer tests. Two wells 33 meters apart were drilled in an unconfined aquifer in Bursa Küçük Sanayi region by Neojen Mühendislik. In one of the wells, a total of 18 slug tests were performed using different volumes before and after well development. Bouwer-Rice and Dagan methods were used as analytical methods and MODFLOW software, which solves groundwater flow problems using method of finite differences, was used for numerical modeling. In the other well, pumping tests were performed. Hantush-Bierschenk and Rorabaugh methods were applied to the data from step-drawdown tests and discharge-drawdown curves were obtained. In addition to these, recovery test and multirate test were performed to determine the hydraulic conductivity. In MODFLOW, simulations were made for various cases related to grid resolution and specific yield. It was observed that well development significantly contributes to well performance and the volume used in slug tests does not affect the results. In addition, different pumping tests modeled in MODFLOW yielded similar values of hydraulic conductivity

Keywords

• Hydraulic conductivity, slug test, recovery test, multirate test, step-drawdown test, MODFLOW

Kuyu ve Akifer Testlerine Uygulanan Analitik ve Sayısal Yöntemlerle Hidrolik İletkenliğin Belirlenmesi

Abstract

Bu çalışmada, kuyu ve akifer testlerinden elde edilen su seviyesi değerleri kullanılarak analitik ve sayısal yöntemlerle akiferin hidrolik iletkenliğinin belirlenmesi amaçlanmıştır. Çalışma kapsamında, Neojen Mühendislik tarafından Bursa Küçük Sanayi bölgesinde bulunan basınçsız bir akiferde aralarında 33 m mesafe bulunan iki adet kuyu açılmıştır. Kuyulardan birinde farklı hacimler kullanılarak inkişaf öncesi ve sonrası olmak üzere toplamda 18 adet slug test yapılmıştır. Analitik yöntem olarak Bouwer-Rice ve Dagan metotları, sayısal modelleme için yeraltı suyu akım problemlerini sonlu farklar metodu ile çözen MODFLOW yazılımı kullanılmıştır. Diğer kuyuda ise pompalama testleri yapılmıştır. Kademeli pompalama test verilerine Hantush-Bierschenk ve Rorabaugh metotları uygulanmış ve debi-düşüm eğrileri elde edilmiştir. Bunlara ek olarak, geri dönüm testi ve değişken debili pompaj testi ile hidrolik iletkenlik belirlenmeye çalışılmıştır. MODFLOW’da grid çözünürlüğüne ve özgül verime dayalı farklı durumlar için simülasyonlar yapılmıştır. Sonuç olarak, inkişafın kuyu performansını belirgin bir şekilde arttırdığı, slug testte kullanılan hacmin sonuçları etkilemediği ve ayrıca MODFLOW ile modellenen farklı pompalama testlerinin verdiği hidrolik iletkenlik değerlerinin birbirine yakın olduğu görülmüştür

Keywords

• Hidrolik iletkenlik, slug test, geri dönüm testi, değişken debili pompaj testi, kademeli pompalama testi, MODFLOW

References

1. Mays,L.W. 2011. Ground and Surface Water Hydrology. Wiley, 617 p.
2. McDonald, M.G., Harbaugh, A.W. 1988. A modular three-dimensional finite- difference ground-water flow model: Techniques of Water-Resources Investigations of the United States Geological Survey, Book 6, Chapter A1, 586 p.
3. Kruseman, G.P., de Ridder N.A. 1990. Analysis and Evaluation of Pumping Test Data. (2nd ed.), Publication 47, Intern. Inst. for Land Reclamation and Improvement, Wageningen, The Netherlands, 370 p.
4. Eryılmaz, G. Kuyu Testlerine Dayalı Analitik ve Sayısal Yöntemlerle Akifer Hidrolik İletkenliğinin Belirlenmesi, Yüksek Lisans Tezi, Uludağ Üniversitesi, 2013.
5. Bouwer, H., Rice R.C. 1976. A slug test method for determining hydraulic conductivity of unconfined aquifers with completely or partially penetrating wells. Water Resources Research, v. 12, no. 3, pp. 423-428.
6. Bouwer, H. 1989. Estimating and enhancing groundwater recharge. In:Sharma ML (ed) Groundwater Recharge. Balkema, Rotterdam, pp 1–10.
7. Zlotnik, V. 1994. Interpretation of slug and packer tests in anisotropic aquifers. Ground Water, v. 32, no. 5, pp. 761-766.
8. Dagan, G. 1978. A note on packer, slug, and recovery tests in unconfined aquifers, Water Resources Research, v. 14, no. 5. pp. 929-934.

9. Butler, J.J., Jr. 1998. The Design, Performance, and Analysis of Slug Tests. Lewis Publishers, New York, 252 p.
10. Jacob, C.E. 1947. Drawdown test to determine effective radius of artesian well. Transactions ASCE, v. 112, pp. 1047-1070.
11. Rorabaugh, M.I. 1953. Graphical and theoretical analysis of step-drawdown test of artesian wells. Proc. Am. Soc. Civ. Eng. Hyd. Div. v.19, no 1, pp. 362.1-362.23.
12. Lennox, D.H. 1966. Analysis and application of step-drawdown tests. Journal of Hydraulics Div., ASCE., v. 92, no. HY 6, pp.25-47.
13. Hantush, M.S. 1964. Hydraulics of wells, in: Advances in Hydroscience, V.T. Chow (editor), Academic Press, New York, pp. 281-442.
14. Bierschenk, W. H. 1963. Determining well efficiency by multiple step-drawdown tests. International Association of Scientific Hydrology Publication, 64, 493-507.
15. Theis, C.V. 1935. The relation between the lowering of the piezometric surface and the rate and duration of discharge of a well using groundwater storage. Am. Geophys. Union Trans., v. 16, pp. 519-524.
16. Nahm, G.Y. 1980. Estimating transmissivity and well loss constant using multirate test data from a pumped well. Ground Water, v. 18, no. 3, 281-285.
17. Cooper, H.H., Jacob, C.E. 1946. A generalized graphical method for evaluating formation constants and summarizing well field history. Am.Geophys. Union Trans. v. 27, pp. 526-534.
18. Jacob, C.E. 1946. Drawdown test to determine effective radius of artesian well. Proc.Am.Soc.Civil Engrs. v.79, no.5.
19. Jacob, C.E. 1944. Notes on determining permeability by pumping tests under water table conditions: U.S. Geol. Survey open-file rept.