Recharge dynamics of a perched phreatic aquifer

Numerous techniques were used to analyze recharge rates, timing, and mechanisms for a perched, phreatic aquifer. Recharge rates were estimated using fluid mass balance (FMB), integrated hydrograph separation (IHS), and innovative hydrograph manipulation techniques. Timing and mechanisms of recharge were analyzed using signal-processing and linear-system approaches. Hydrometeorologic and hydrologic data were collected for a 16-month period (4/97 to 8/98) using both manual and automated techniques. Precipitation totaled 135.6 cm and evapotranspiration (ET) calculated using the Penman-Monteith method totaled 107.5 cm. Recharge estimates from FMB ranged from 20.3% to 33.6%. Springflows were modeled using a stage-discharge cross-correlation method. Recharge estimates from IHS of these springflows ranged from 59.8% to 72.2% (significantly higher than FMB estimates).;Conventional well-stage hydrographs were corrected for spring discharge using cross-correlation relationships resulting in storage accumulation curves (SACs). Recharge estimates using SACs corresponded well to IHS estimates and ranged between 49.0% and 74.2%. These curves represent a potentially powerful technique for recharge estimation over short-scale intervals (days to weeks).;Modified storage accumulation curves (MSACs), based on the slope of the SAC, were used to analyze recharge timing and mechanisms. A linear groundwater system was identified relating precipitation to water-level fluctuations and four signal-processing techniques were used to develop kernel functions. These kernels revealed that a significant amount of recharge occurs on the same day as precipitation. They also showed that both macropore and matrix processes are at work in this system.

Name thesis:degree_name

MS

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Geology and Geography

Year dc:date.available

1998

Author dc:creator

• Ketchum, Joseph Neil, Jr.

Contributors dc:contributor

• Joseph J. Donovan.

• Geology
• Hydrologic sciences

Identifier

https://researchrepository.wvu.edu/etd/919

OAI identifier oai:identifier

oai:researchrepository.wvu.edu:etd-1922