Warning: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at /home/aprchile/public_html/index.php:3) in /home/aprchile/public_html/libraries/joomla/session/session.php on line 423

Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /home/aprchile/public_html/index.php:3) in /home/aprchile/public_html/libraries/joomla/session/session.php on line 423

Warning: Cannot modify header information - headers already sent by (output started at /home/aprchile/public_html/index.php:3) in /home/aprchile/public_html/libraries/joomla/session/session.php on line 426
Case Study A Comparison of Well Efficiency and Aquifer Test Results
Technical Memorandum 004-1 - Case Study A Comparison of Well Efficiency and Aquifer Test Results Imprimir
Miércoles, 13 de Abril de 2011 03:13
Executive Summary
rate
Aquifer test results demonstrated that the performances of louvered screen and continuous wire-wrapped screen were essentially equal for two high-capacity water supply wells constructed near Big Pine, California. The as-built designs of the two wells, spaced 1,000 feet apart, were equivalent in depth, diameter, and total screen length. Both wells were completed to pump ground water from the same confined, alluvial aquifer. The results of step-drawdown and constant-rate discharge tests showed very minor differences in transmissivity values and well efficiencies between the two wells. The long-term projected yields and permanent pumps selected for the wells were the same. These results clearly show that the properties of high efficiency and long term productivity are offered by either louvered screen or continuous wire-wrapped screen.
Background
Big Pine, California is located in the Owens Valley which lies between the Sierra Nevada Mountains on the west and the Inyo and White Mountain Ranges on the east. The valley is major ground water reservoir filled with alluvium and volcanic deposits that are reservoir materials (i.e., aquifers) that yield ground water to numerous water wells.
The Los Angeles Department of Water and Power (LADWP) constructed two water supply wells (Nos. 374 and 375) at sites located southeast of the town of Big Pine and approximately 1.4 miles east of Highway 395. The two wells were approximately 1,000 feet apart and were located near two monitoring wells previously installed by the United States Geological Survey (USGS).
Well Designs
After drilling the pilot hole with a conventional mud rotary drilling rig and geophysical logging, each well was constructed to a depth of 450 feet. Both wells were constructed with 18-inch diameter blank casing (0.313-inch wall thickness) and gravel packed. The production zone for each well was from a depth of 260 to 440 feet. Well No. 374 was completed with 180 feet of continuous wire-wrapped well screen with an aperture size of 0.080 inches. Well No. 375 had an identical length of Roscoe Moss Company “Ful Flo” louvered screen with an aperture size of 0.080 inches. The as-built design details are presented below.
Enviado por Raúl Campillo U., Hidrogeólogo.