کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4578171 1630051 2010 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Spatial variability of specific yield and vertical hydraulic conductivity in a highly permeable alluvial aquifer
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Spatial variability of specific yield and vertical hydraulic conductivity in a highly permeable alluvial aquifer
چکیده انگلیسی

SummaryLower-than-expected specific yield values of an unconfined aquifer estimated from pumping test data have been a concern in the groundwater community over the last several decades. Delayed yield above the declining water table during pumping has been considered the primary cause of this uncertainty in the specific yield. The drainage process above the declining water table is a dominantly downward flow. Thus, the vertical hydraulic conductivity (Kv) must have an effect on the drainage process. However, careful examination of Kv variation has not been done. The spatial variation of Sy has not been well evaluated either. This paper examines the heterogeneity of the specific yield and the vertical hydraulic conductivity of an alluvial aquifer. A drainage experiment and permeameter tests using more than 60 sediment cores were conducted to determine specific yield and the vertical hydraulic conductivity. Drainage experiments indicated that more than 50% of drainable water was released from the permeable sediment cores in less than 2 h, and nearly 100% of drainable water was released from most of the cores within 24 h. Thus, the appreciable effect of delayed yield in a permeable aquifer is unlikely to last longer than 24 h. Both Sy and Kv indicated a strong tendency of variation between one and another sediment core, and the two variables have some correlation. Because Kv is heterogeneous and the two parameters are correlated, holding a constant Kv value for different observation wells in the analysis of pumping test data can introduce errors to the derived Sy values.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Hydrology - Volume 388, Issues 3–4, 15 July 2010, Pages 379–388
نویسندگان
, , ,