{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/72245"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/72245","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Methods for Evaluating Aquifer-System Parameters from a Cumulative Compaction Record","abstract":"Although many efforts and strategies have been implemented to reduce over-pumping of aquifer-systems, land subsidence is still a serious issue worldwide. Accurate aquifer characterization is critical to understand the response of an aquifer-system to prolonged pumping but is often difficult and expensive to conduct. The purpose of this thesis is to determine the validity of estimating aquifer-system parameters from a single cumulative compaction record and corresponding nested water-level data deconvolved into temporal components. Over a decade of compaction and water-level data were collected from an extensometer and multi-level piezometer at the Lorenzi site in Las Vegas Valley and when graphed yearly, seasonal, and daily signals are observed. Each temporal signal reflects different characteristics of the aquifer-system, including the distinction between aquifer and aquitard parameters, as the three temporal stresses influence the compaction record uniquely. Maximum cross-correlation was used to determine the hydrodynamic lag between changing water-levels and subsidence within the seasonal signal while principal components analysis was used to statistically verify the presence of the three temporal signals. Assumptions had to be made but nearly all estimated Lorenzi site aquifer-system parameters fell either within the reasonable range or were similar in magnitude to parameter values estimated in previous studies. Unfortunately, principal components analysis was unable to detect the three temporal signals. A cumulative compaction record may be difficult to obtain but analyzing the precision measurements of an extensometer results in precise aquifer-system parameters and as the precision of aquifer-system parameters increase so does the ability to sustainably manage groundwater.","abstract_html":"Although many efforts and strategies have been implemented to reduce over-pumping of aquifer-systems, land subsidence is still a serious issue worldwide. Accurate aquifer characterization is critical to understand the response of an aquifer-system to prolonged pumping but is often difficult and expensive to conduct. The purpose of this thesis is to determine the validity of estimating aquifer-system parameters from a single cumulative compaction record and corresponding nested water-level data deconvolved into temporal components. Over a decade of compaction and water-level data were collected from an extensometer and multi-level piezometer at the Lorenzi site in Las Vegas Valley and when graphed yearly, seasonal, and daily signals are observed. Each temporal signal reflects different characteristics of the aquifer-system, including the distinction between aquifer and aquitard parameters, as the three temporal stresses influence the compaction record uniquely. Maximum cross-correlation was used to determine the hydrodynamic lag between changing water-levels and subsidence within the seasonal signal while principal components analysis was used to statistically verify the presence of the three temporal signals. Assumptions had to be made but nearly all estimated Lorenzi site aquifer-system parameters fell either within the reasonable range or were similar in magnitude to parameter values estimated in previous studies. Unfortunately, principal components analysis was unable to detect the three temporal signals. A cumulative compaction record may be difficult to obtain but analyzing the precision measurements of an extensometer results in precise aquifer-system parameters and as the precision of aquifer-system parameters increase so does the ability to sustainably manage groundwater.","abstract_has_math":false,"creators":["Vanhaitsma, Amanda Joy"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Geosciences","degree_department":"Geosciences","school":null,"contributors":[],"advisors":[],"committee_chairs":["Burbey, Thomas J."],"committee_members":["Schreiber, Madeline E.","Du, Pang"],"year":2016,"date_issued":"2016-08-12","date_published":"2016-08-12","updated_at":"2026-07-22T22:20:05Z","subjects":["aquifer-system parameters","compaction","Lorenzi site","Las Vegas","subsidence"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:8281"],"render_values":[{"text":"vt_gsexam:8281","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/72245","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Burbey, Thomas J."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Schreiber, Madeline E.","Du, Pang"]},{"key":"dc:contributor.department","label":"Department","values":["Geosciences"]},{"key":"dc:creator","label":"Author","values":["Vanhaitsma, Amanda Joy"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2016-08-13T08:00:13Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2016-08-13T08:00:13Z"]},{"key":"dc:date.issued","label":"Date","values":["2016-08-12"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Geosciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["aquifer-system parameters","compaction","Lorenzi site","Las Vegas","subsidence"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:8281"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/72245"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Although many efforts and strategies have been implemented to reduce over-pumping of aquifer-systems, land subsidence is still a serious issue worldwide. Accurate aquifer characterization is critical to understand the response of an aquifer-system to prolonged pumping but is often difficult and expensive to conduct. The purpose of this thesis is to determine the validity of estimating aquifer-system parameters from a single cumulative compaction record and corresponding nested water-level data deconvolved into temporal components. Over a decade of compaction and water-level data were collected from an extensometer and multi-level piezometer at the Lorenzi site in Las Vegas Valley and when graphed yearly, seasonal, and daily signals are observed. Each temporal signal reflects different characteristics of the aquifer-system, including the distinction between aquifer and aquitard parameters, as the three temporal stresses influence the compaction record uniquely. Maximum cross-correlation was used to determine the hydrodynamic lag between changing water-levels and subsidence within the seasonal signal while principal components analysis was used to statistically verify the presence of the three temporal signals. Assumptions had to be made but nearly all estimated Lorenzi site aquifer-system parameters fell either within the reasonable range or were similar in magnitude to parameter values estimated in previous studies. Unfortunately, principal components analysis was unable to detect the three temporal signals. A cumulative compaction record may be difficult to obtain but analyzing the precision measurements of an extensometer results in precise aquifer-system parameters and as the precision of aquifer-system parameters increase so does the ability to sustainably manage groundwater."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:title","label":"Title","values":["Methods for Evaluating Aquifer-System Parameters from a Cumulative Compaction Record"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Burbey, Thomas J."],"dc:contributor.committeemember":["Schreiber, Madeline E.","Du, Pang"],"dc:contributor.department":["Geosciences"],"dc:creator":["Vanhaitsma, Amanda Joy"],"dc:date.accessioned":["2016-08-13T08:00:13Z"],"dc:date.available":["2016-08-13T08:00:13Z"],"dc:date.issued":["2016-08-12"],"dc:description.abstract":["Although many efforts and strategies have been implemented to reduce over-pumping of aquifer-systems, land subsidence is still a serious issue worldwide. Accurate aquifer characterization is critical to understand the response of an aquifer-system to prolonged pumping but is often difficult and expensive to conduct. The purpose of this thesis is to determine the validity of estimating aquifer-system parameters from a single cumulative compaction record and corresponding nested water-level data deconvolved into temporal components. Over a decade of compaction and water-level data were collected from an extensometer and multi-level piezometer at the Lorenzi site in Las Vegas Valley and when graphed yearly, seasonal, and daily signals are observed. Each temporal signal reflects different characteristics of the aquifer-system, including the distinction between aquifer and aquitard parameters, as the three temporal stresses influence the compaction record uniquely. Maximum cross-correlation was used to determine the hydrodynamic lag between changing water-levels and subsidence within the seasonal signal while principal components analysis was used to statistically verify the presence of the three temporal signals. Assumptions had to be made but nearly all estimated Lorenzi site aquifer-system parameters fell either within the reasonable range or were similar in magnitude to parameter values estimated in previous studies. Unfortunately, principal components analysis was unable to detect the three temporal signals. A cumulative compaction record may be difficult to obtain but analyzing the precision measurements of an extensometer results in precise aquifer-system parameters and as the precision of aquifer-system parameters increase so does the ability to sustainably manage groundwater."],"dc:description.degree":["Master of Science"],"dc:format.medium":["ETD"],"dc:identifier.other":["vt_gsexam:8281"],"dc:identifier.uri":["http://hdl.handle.net/10919/72245"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["aquifer-system parameters","compaction","Lorenzi site","Las Vegas","subsidence"],"dc:title":["Methods for Evaluating Aquifer-System Parameters from a Cumulative Compaction Record"],"dc:type":["Thesis"],"thesis:degree_discipline":["Geosciences"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:05Z"}