Infiltration into Fractured Bedrock
One potential consequence of global climate change and rapid changes in land use is an increased risk of flooding. Proper understanding of floodwater infiltration thus becomes a crucial component of our preparedness to meet the environmental challenges of projected climate change. In this paper, we present the results of a long-term infiltration experiment performed on fractured ash flow tuff. Water was released from a 3 x 4 m{sup 2} infiltration plot (divided into 12 square subplots) with a head of {approx}0.04 m, over a period of {approx}800 days. This experiment revealed peculiar infiltration patterns not amenable to current infiltration models, which were originally developed for infiltration into soils over a short duration. In particular, we observed that in part of the infiltration plot, the infiltration rate abruptly increased a few weeks into the infiltration tests. We suggest that these anomalies result from increases in fracture permeability during infiltration, which may be caused by swelling of clay fillings and/or erosion of infill debris. Interaction of the infiltration water with subsurface natural cavities (lithophysal cavities) could also contribute to such anomalies. This paper provides a conceptual model that partly describes the observed infiltration patterns in fractured rock and highlights some of the pitfalls associated with direct extension of soil infiltration models to fractured rock over a long period.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE. Office of Civilian Radioactive Waste Management.Waste Management System
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 929027
- Report Number(s):
- LBNL-63628; WRERAQ; R&D Project: G60691; BnR: DF0961000; TRN: US200811%%488
- Journal Information:
- Water Resources Research, Vol. 44, Issue 1; Related Information: Journal Publication Date: 01/26/2008; ISSN 0043-1397
- Country of Publication:
- United States
- Language:
- English
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