{"id":574,"date":"2025-11-21T00:50:27","date_gmt":"2025-11-21T00:50:27","guid":{"rendered":"https:\/\/books.gw-project.org\/an-introduction-to-hydraulic-testing-in-hydrogeology\/?post_type=part&#038;p=574"},"modified":"2026-08-01T08:59:11","modified_gmt":"2026-08-01T08:59:11","slug":"8-transient-analytical-model-for-pumping-of-a-fully-confined-aquifer","status":"publish","type":"part","link":"https:\/\/books.gw-project.org\/an-introduction-to-hydraulic-testing-in-hydrogeology\/part\/8-transient-analytical-model-for-pumping-of-a-fully-confined-aquifer\/","title":{"raw":"8 Transient Analytical Model for Pumping of a Fully Confined Aquifer","rendered":"8 Transient Analytical Model for Pumping of a Fully Confined Aquifer"},"content":{"raw":"<div data-custom-style=\"First Paragraph\">\r\n<div data-custom-style=\"First Paragraph\">\r\n\r\nA hydrogeologic unit is considered confined when the heads in tightly cased wells are higher than the top of the unit. The surface defining the head distribution is referred to as the potentiometric surface (Woessner &amp; Poeter, 2020, Figure 46). The pressure in confined systems exceeds the hydrostatic pressure.\r\n\r\n<\/div>\r\n<div data-custom-style=\"Body Text\">\r\n\r\nC. V. Theis (1935), with the assistance of C. I. Lubin, applied the mathematics that describe a <em>\u201c\u2026continuous point source for a heat conduction problem\u201d<\/em> (Lohman, 1972), to formulate an analytical solution for flow to a well in a confined aquifer under transient conditions. Transient conditions are non\u2011equilibrium conditions. The Theis solution (1935) describes how a confined groundwater system would react to pumping over time. This was the first transient model available for analyzing non\u2011steady time\u2011drawdown data sets. Prior to his work, wells would be pumped for long periods until drawdown reached steady\u2011state or pseudo\u2011steady\u2011state conditions (as described in Section 7). Then drawdown versus distance data would be analyzed using the Thiem steady\u2011state equations. Theis\u2019s non\u2011equilibrium analyses resulted in shorter hydraulic tests in which time\u2011drawdown data are used to derive hydraulic properties of confined systems.\r\n\r\n<\/div>\r\n<\/div>","rendered":"<div data-custom-style=\"First Paragraph\">\n<div data-custom-style=\"First Paragraph\">\n<p>A hydrogeologic unit is considered confined when the heads in tightly cased wells are higher than the top of the unit. The surface defining the head distribution is referred to as the potentiometric surface (Woessner &amp; Poeter, 2020, Figure 46). The pressure in confined systems exceeds the hydrostatic pressure.<\/p>\n<\/div>\n<div data-custom-style=\"Body Text\">\n<p>C. V. Theis (1935), with the assistance of C. I. Lubin, applied the mathematics that describe a <em>\u201c\u2026continuous point source for a heat conduction problem\u201d<\/em> (Lohman, 1972), to formulate an analytical solution for flow to a well in a confined aquifer under transient conditions. Transient conditions are non\u2011equilibrium conditions. The Theis solution (1935) describes how a confined groundwater system would react to pumping over time. This was the first transient model available for analyzing non\u2011steady time\u2011drawdown data sets. Prior to his work, wells would be pumped for long periods until drawdown reached steady\u2011state or pseudo\u2011steady\u2011state conditions (as described in Section 7). Then drawdown versus distance data would be analyzed using the Thiem steady\u2011state equations. Theis\u2019s non\u2011equilibrium analyses resulted in shorter hydraulic tests in which time\u2011drawdown data are used to derive hydraulic properties of confined systems.<\/p>\n<\/div>\n<\/div>\n","protected":false},"parent":0,"menu_order":10,"template":"","meta":{"pb_part_invisible":false,"pb_part_invisible_string":""},"contributor":[],"license":[],"class_list":["post-574","part","type-part","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/books.gw-project.org\/an-introduction-to-hydraulic-testing-in-hydrogeology\/wp-json\/pressbooks\/v2\/parts\/574","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/books.gw-project.org\/an-introduction-to-hydraulic-testing-in-hydrogeology\/wp-json\/pressbooks\/v2\/parts"}],"about":[{"href":"https:\/\/books.gw-project.org\/an-introduction-to-hydraulic-testing-in-hydrogeology\/wp-json\/wp\/v2\/types\/part"}],"version-history":[{"count":3,"href":"https:\/\/books.gw-project.org\/an-introduction-to-hydraulic-testing-in-hydrogeology\/wp-json\/pressbooks\/v2\/parts\/574\/revisions"}],"predecessor-version":[{"id":2966,"href":"https:\/\/books.gw-project.org\/an-introduction-to-hydraulic-testing-in-hydrogeology\/wp-json\/pressbooks\/v2\/parts\/574\/revisions\/2966"}],"wp:attachment":[{"href":"https:\/\/books.gw-project.org\/an-introduction-to-hydraulic-testing-in-hydrogeology\/wp-json\/wp\/v2\/media?parent=574"}],"wp:term":[{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/books.gw-project.org\/an-introduction-to-hydraulic-testing-in-hydrogeology\/wp-json\/wp\/v2\/contributor?post=574"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/books.gw-project.org\/an-introduction-to-hydraulic-testing-in-hydrogeology\/wp-json\/wp\/v2\/license?post=574"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}