Hydrogeological Study Report, Lajes Field, Azores, Portugal
Abstract
This initial hydrogeologic study at Lajes Field Azores Portugal was initiated to investigate the groundwater aquifers which underlie the already identified suspected and contaminated sites of Lajes Field and to determine any resulting risk. It was programmed to gain basic information on the groundwater situation that could help to understand possible pathways and risk to receptors in support of the HO USAFE restoration program. There are two kinds of aquifers present in the Lajes area: 1) A basal aquifer that occurs in very permeable fractured volcanic rocks and has groundwater levels near sea level. 2) Numerous discontinuous perched aquifers that occur in areas where precipitation that infiltrates the surface is impeded by lower permeability materials in the subsurface such as paleosols or low permeability lava flows. The basal aquifer is the only source of groundwater supply to Lajes Field. The wells in the Base well field tap a thin (approximately 18 to 20 m thick) freshwater lens. Upconing of saline water in to these wells is possible if the wells are pumped at excessive rates or/and if the pumps are not installed at the correct levels in the basal aquifer. Potential impact on the quality of water pumped from the Base wells is discussed together with recommendations on improvements at the Base well field.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2005
- Accession Number
- ADA433709
Entities
People
- Fritz Carlson
- Joerg Schaller