{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,31]],"date-time":"2026-01-31T02:46:01Z","timestamp":1769827561136,"version":"3.49.0"},"reference-count":28,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2026,1,26]],"date-time":"2026-01-26T00:00:00Z","timestamp":1769385600000},"content-version":"vor","delay-in-days":25,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,1,1]],"date-time":"2026-01-01T00:00:00Z","timestamp":1767225600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["ngwa.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Groundwater"],"published-print":{"date-parts":[[2026,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>A sophisticated understanding of the three\u2010dimensional distribution of silt\u2010 and clay\u2010rich bodies of strata (elements) in aquifers is critical given that they not only have the potential to act as aquitards or semi\u2010confining units and vertically partition groundwater flow into separate aquifer zones, but also provide lateral barriers to groundwater flow, impacting contaminant distribution and groundwater flow dynamics. Additionally, when in prolonged contact with dense nonaqueous phase liquid (DNAPL) or contaminated groundwater, fine\u2010grained elements may become storage zones for contaminant mass via matrix diffusion and thus serve as long\u2010term secondary sources of contamination to groundwater that can confound remediation strategies and render remedy performance projections unreliable. The stratigraphic architecture of aquifer systems, including fine\u2010grained facies architecture, is complex but is not random and can be effectively predicted through application of facies models. This paper reviews depositional models (\u201cfacies models\u201d) for common depositional environments with a focus on alluvial end\u2010members of braided fluvial, meandering fluvial, and alluvial fan facies models. We examine the facies models from the perspective of aquitards and present case studies to provide an overview of the expected aquitard dimensions and characteristics. The critical yet underappreciated role of the paleosol as a potential aquitard is also examined, and basic criteria for differentiating ancient floodplain clay units with high lateral continuity from other laterally discontinuous clay units are provided.<\/jats:p>","DOI":"10.1111\/gwat.70048","type":"journal-article","created":{"date-parts":[[2026,1,26]],"date-time":"2026-01-26T18:14:36Z","timestamp":1769451276000},"page":"30-40","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["The Geology of Aquitards in Alluvial Aquifers: A Predictive Approach Based on Facies Models"],"prefix":"10.1111","volume":"64","author":[{"ORCID":"https:\/\/orcid.org\/0009-0009-6428-4640","authenticated-orcid":false,"given":"Michael R.","family":"Shultz","sequence":"first","affiliation":[{"name":"Geosyntec Consultants, Inc.  Minneapolis Minnesota"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Colin","family":"Plank","sequence":"additional","affiliation":[{"name":"Geosyntec Consultants, Inc.  Grand Rapids Michigan; colin.plank@geosyntec.com"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2026,1,26]]},"reference":[{"key":"e_1_2_14_2_1","doi-asserted-by":"publisher","DOI":"10.1130\/B35909.1"},{"key":"e_1_2_14_3_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-94-015-8254-4_14"},{"key":"e_1_2_14_4_1","doi-asserted-by":"publisher","DOI":"10.1306\/212F8BB1\u20102B24\u201011D7\u20108648000102C1865D"},{"key":"e_1_2_14_5_1","volume-title":"Principles of Sequence Stratigraphy","author":"Catuneanu O.","year":"2006"},{"key":"e_1_2_14_6_1","volume-title":"Geology of the National Capital Region\u2014Field Trip Guidebook (U.S. Geological Survey Circular 1264)","author":"Cecil C.B.","year":"2004"},{"key":"e_1_2_14_7_1","series-title":"Concepts in Sedimentology and Paleontology #18","volume-title":"The Handbook of Siliciclastic Facies: A Guide to the Interpretation of Depositional Environments","author":"Cleveland D.M.","year":"2024"},{"key":"e_1_2_14_8_1","doi-asserted-by":"publisher","DOI":"10.3390\/su17052027"},{"key":"e_1_2_14_9_1","first-page":"221","volume-title":"Proceedings of the American Association of Water Resources Symposium, Conjunctive Use of Water Resources: Aquifer Storage and Recovery","author":"Ehman K.D.","year":"1997"},{"key":"e_1_2_14_10_1","unstructured":"Einarson M.2025.Procedure for generating optimized numerical models from the new generation of advanced geologic site conceptual models developed using Environmental Sequence Stratigraphy (ESS) (ER21\u20105226).https:\/\/serdp\u2010estcp.mil\/projects\/details\/3b222eba\u2010f922\u20104cc9\u20109c1e\u2010c6f6701afdd3"},{"key":"e_1_2_14_11_1","series-title":"Concepts in Sedimentology and Paleontology #18","volume-title":"The Handbook of Siliciclastic Facies: A Guide to the Interpretation of Depositional Environments","author":"Feldman Howard R.","year":"2024"},{"key":"e_1_2_14_12_1","doi-asserted-by":"publisher","DOI":"10.2110\/jsr.2010.016"},{"key":"e_1_2_14_13_1","doi-asserted-by":"publisher","DOI":"10.1130\/2020.2516(02)"},{"key":"e_1_2_14_14_1","doi-asserted-by":"publisher","DOI":"10.1029\/96WR00025"},{"key":"e_1_2_14_15_1","doi-asserted-by":"publisher","DOI":"10.1016\/0022\u20101694(64)90023\u2010X"},{"key":"e_1_2_14_16_1","doi-asserted-by":"publisher","DOI":"10.1111\/gwmr.12521"},{"key":"e_1_2_14_17_1","volume-title":"Alternatives for Managing the Nation's Complex Contaminated Groundwater Sites","author":"National Research Council","year":"2013"},{"key":"e_1_2_14_18_1","unstructured":"Noyes C.M. M.P.Maley andR.G.Blake.2001.Defining hydrostratigraphic units within the heterogeneous alluvial sediments at Lawrence Livermore National Laboratory. Presented at the AAPG Pacific Section Meeting Universal City California."},{"key":"e_1_2_14_19_1","doi-asserted-by":"publisher","DOI":"10.2110\/pec.06.84"},{"key":"e_1_2_14_20_1","first-page":"12","volume-title":"Low\u2010Flow (Minimal Drawdown) Ground\u2010Water Sampling Procedures","author":"Puls R.W.","year":"1996"},{"key":"e_1_2_14_21_1","volume-title":"Advances in the Characterization and Remediation of Sites Contaminated with Petroleum Hydrocarbons, Environmental Contamination Remediation and Management","author":"Sadeque J.","year":"2024"},{"key":"e_1_2_14_22_1","unstructured":"Shultz M.andT.Champion.2015.Complex site investigation for Buckley Air Force Base Aurora Colorado United States Air Force Administrative Record for Buckley AFB #872."},{"key":"e_1_2_14_23_1","volume-title":"Best Practices for Environmental Site Management: A Practical Guide for Applying Environmental Sequence Stratigraphy to Improve Conceptual Site Models","author":"Shultz M.","year":"2017"},{"key":"e_1_2_14_24_1","doi-asserted-by":"publisher","DOI":"10.1111\/gwmr.12608"},{"key":"e_1_2_14_25_1","article-title":"Silicislastic sequence stratigraphy in well logs, cores, and outcrops: Concepts for high\u2010resolution correlation of time and facies","volume":"7","author":"Van Wagoner J.","year":"1990","journal-title":"AAPG Methods in Exploration Series"},{"key":"e_1_2_14_26_1","volume-title":"Facies Models: Response to Sea Level Change","author":"Walker R.G.","year":"1992"},{"key":"e_1_2_14_27_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-1694(99)00160-2"},{"key":"e_1_2_14_28_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-1-4613-8988-0_5"},{"key":"e_1_2_14_29_1","volume-title":"Palaeosurfaces: Geological and Geomorphological Significance","author":"Wright V.P.","year":"2024"}],"container-title":["Groundwater"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/ngwa.onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/gwat.70048","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/ngwa.onlinelibrary.wiley.com\/doi\/full-xml\/10.1111\/gwat.70048","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/ngwa.onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/gwat.70048","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,30]],"date-time":"2026-01-30T14:14:02Z","timestamp":1769782442000},"score":1,"resource":{"primary":{"URL":"https:\/\/ngwa.onlinelibrary.wiley.com\/doi\/10.1111\/gwat.70048"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1]]},"references-count":28,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2026,1]]}},"alternative-id":["10.1111\/gwat.70048"],"URL":"https:\/\/doi.org\/10.1111\/gwat.70048","archive":["Portico"],"relation":{},"ISSN":["0017-467X","1745-6584"],"issn-type":[{"value":"0017-467X","type":"print"},{"value":"1745-6584","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1]]},"assertion":[{"value":"2025-07-11","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-12-02","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-01-26","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}