Off-campus UMass Amherst users: To download dissertations, please use the following link to log into our proxy server with your UMass Amherst user name and password.
Non-UMass Amherst users, please click the view more button below to purchase a copy of this dissertation from Proquest.
(Some titles may also be available free of charge in our Open Access Dissertation Collection, so please check there first.)
Lineaments: Their value in assessing groundwater availability and quality in bedrock aquifers of glaciated metamorphic terrains. A case study
A lineament analysis for Georgetown, Maine, a 44 km$\sp2$ island community situated on the central Maine coast, was performed to evaluate the relationship between mapped lineaments and (1) outcrop fractures, (2) well productivity (35 wells), and (3) groundwater quality determined from a sample of 87 existing bedrock wells. Lineaments were drawn by three observers using two scales of imagery (SLAR and a 1:80,000 Aerial Photograph). Rigorous reproducibility testing indicates that the ability of individual observers to reproduce lineaments at the same geographic location is low; more than 55% of all lineaments mapped by any observer were not reproducible. This casts doubt as to how many lineaments may be considered real features. In addition, when azimuthal sets of near-vertical outcrop fractures are compared with reproducible lineament domains of similar azimuth on a regional basis, distinct areas of overlap are defined across the island. The extent of this overlap is not uniform. Some lineament domains (165$\sp\circ$) exhibit no correlation with fracture fabric whereas other lineament domains (120$\sp\circ$) only show a correlation with fracture fabric in a very limited geographic area. In regard to well productivity, wells located "on" lineaments, specifically those lineaments showing a geographic correlation with similar-trending fracture domains, are generally more productive than non-lineament wells. If the same analysis is repeated, but is performed without considering whether or not the lineaments used in the analysis are geographically correlative with fracture domains, no differences are observed between the productivities of lineament and non-lineament wells. However, in this study, other geologic factors exhibit strong influences on high productivity in bedrock wells. Bedrock type (amphibolite) is the dominant and only statistically significant influence on well productivity followed by depth to the water table (shallow depths), proximity to lineaments (specifically those that correlate geographically with outcrop fractures), topographic position (flatter hydraulic gradients), and proximity to surface water bodies, in order of decreasing importance. Groundwater chemistry is controlled primarily by bedrock type, topographic setting, structural position, and overburden type and thickness. The chemical character of groundwater sampled from bedrock wells is generally not influenced by the proximity of a well to a lineament.
Mabee, Stephen B, "Lineaments: Their value in assessing groundwater availability and quality in bedrock aquifers of glaciated metamorphic terrains. A case study" (1992). Doctoral Dissertations Available from Proquest. AAI9233095.