Mechanisms of water storage and flow in the unsaturated zone of the Chalk aquifer
- Permanent Link:
- Mechanisms of water storage and flow in the unsaturated zone of the Chalk aquifer
- Series Title:
- Journal of Hydrology
- Price, M.
- Publication Date:
- Subjects / Keywords:
- Chalk ( local )
Unsaturated Zone ( local )
Storage ( local )
Recharge ( local )
Fissure Flow ( local )
Matrix ( local )
- serial ( sobekcm )
- It is known that the volumes of water draining from some Chalk catchments in recessions are significantly greater than can be explained by gravity drainage from fissure porosity. The most likely source of this water is slow drainage from the matric porosity above the water table. This paper suggests that the location of this storage is in the irregularities on the fissure surfaces. Studies of resin-impregnated blocks of chalk failed to reveal the presence of hydrologically significant microfissures or macropores that could be the source of additional drainage. Ultrasonic measurements at varying values of effective stress show no indication of changes in the acoustic transmission properties that could be attributed to closure of microfissures. Drainage and mercury-intrusion measurements indicate that there is significant storage on block surfaces. The drainage measurements confirm that the storage is of the order of magnitude (about 0.3%) needed to explain the slow drainage. This additional storage explains why the water table is slow to respond after recharge events, and why the Chalk is resilient to drought. The presence of storage in the unsaturated zone implies that the position of the water table may not be an accurate indicator of groundwater resources. The concept of filling and draining of irregularities on fissure surfaces also leads to a new model for the generation of fissure flow in the unsaturated zone of the Chalk. This suggests that fissure flow can be generated at any depth in the profile, and in a sequence of uniform vertical permeability is likely to originate near the water table rather than high in the unsaturated zone.
- Original Version:
- Journal of Hydrology, Vol. 233, no. 1--4 (2000-06-12).
- Source Institution:
- University of South Florida Library
- Holding Location:
- University of South Florida
- Rights Management:
- This object is protected by copyright, and is made available here for research and educational purposes. Permission to reuse, publish, or reproduce the object beyond the bounds of Fair Use or other exemptions to copyright law must be obtained from the copyright holder.
No images or PDF downloads are available for this resource.
Cras ut cursus ante, a fringilla nunc. Mauris lorem nunc, cursus sit amet enim ac, vehicula vestibulum mi. Mauris viverra nisl vel enim faucibus porta. Praesent sit amet ornare diam, non finibus nulla.
Cras efficitur magna et sapien varius, luctus ullamcorper dolor convallis. Orci varius natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Fusce sit amet justo ut erat laoreet congue sed a ante.
Phasellus ornare in augue eu imperdiet. Donec malesuada sapien ante, at vehicula orci tempor molestie. Proin vitae urna elit. Pellentesque vitae nisi et diam euismod malesuada aliquet non erat.
Nunc fringilla dolor ut dictum placerat. Proin ac neque rutrum, consectetur ligula id, laoreet ligula. Nulla lorem massa, consectetur vitae consequat in, lobortis at dolor. Nunc sed leo odio.