1 / 4

Storage Coefficients/Specific Yield

Storage Coefficients/Specific Yield. Storage Coefficient/Storativity. S: storage coefficient or storativity: The amount of water stored or released per unit area of aquifer given unit head change Ss: specific storage

Samuel
Télécharger la présentation

Storage Coefficients/Specific Yield

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Storage Coefficients/Specific Yield

  2. Storage Coefficient/Storativity • S: storage coefficient or storativity: The amount of water stored or released per unit area of aquifer given unit head change • Ss: specific storage • The amount of water stored or released per unit volume of aquifer given unit head change • S = Ss b, where b is the aquifer thickness • Storage change is accomplished via compression of the aquifer matrix and the fluid. Fluid compressibility 10-10 Pa-1 while typical (sand) aquifer compressibility is 10-8 Pa-1 • Typical values of S (dimensionless) are 10-5 – 10-3 • Measuring storativity: derived from observations of multi-well tests • GEOS 4310/5310 Lecture Notes, Fall 2002Dr. T. Brikowski, UTD http://www.utdallas.edu/~brikowi/Teaching/Geohydrology/LectureNotes/Regional_Flow/Storativity.html

  3. Storage Coefficient/Storativity

  4. Specific Yield Determination of Specific Yield for the Biscayne Aquifer with a Canal-Drawdown Test by Carl H. Bolster, David P. Genereux, and James E. Saiers Abstract Data from a large-scale canal-drawdown test were used to estimate the specific yield (sy) of the Biscayne Aquifer, an unconfined limestone aquifer in southeast Florida. The drawdown test involved dropping the water level in a canal by about 30 cm and monitoring the response of hydraulic head in the surrounding aquifer. Specific yield was determined by analyzing data from the unsteady portion of the drawdown test using an analytical stream-aquifer interaction model (Zlotnik and Huang 1999). Specific yield values computed from drawdown at individual piezometers ranged from 0.050 to 0.57, most likely indicating heterogeneity of specific yield within the aquifer (small-scale variation in hydraulic conductivity may also have contributed to the differences in Sy among piezometers). A value of 0.15 (our best estimate) was computed based on all drawdown data from all piezometers. We incorporated our best estimate of specific yield into a large-scale two-dimensional numerical MODFLOW-based ground water flow model and made predictions of head during a 183-day period at four wells located 337 to 2546 m from the canal. We found good agreement between observed and predicted heads, indicating our estimate of specific yield is representative of the large portion of the Biscayne Aquifer studied here. This work represents a practical and novel approach to the determination of a key hydrogeological parameter (the storage parameter needed for simulation and calculation of transient unconfined ground water flow), at a large spatial scale (a common scale for water resource modeling), for a highly transmissive limestone aquifer (in which execution of a traditional pump test would be impractical and would likely yield ambiguous results). … Ground Water Abstracts Volume 39 Number 5 September/October 2001/

More Related