Tipping, Robert G2021-05-042021-05-042019https://hdl.handle.net/11299/219591Historically, the goal of subsurface Quaternary sediment mapping at the Minnesota Geological Survey (MGS) has been to provide information on the distribution and inferred depositional environment of coarse- to fine-grained material, herein broadly defined as glaciofluvial (sand and gravel) and supraglacial to subglacial (till). More recently, map units have been named according to a formalized lithostratigraphic nomenclature (Johnson et al., 2016) providing, for the first time, a consistent framework for understanding the history of repeated glacial advances in Minnesota. When combined with advances in three-dimensional subsurface modeling, this framework will be used by ground and surface water resource managers to view subsurface aquifer and aquitard distributions across traditional political and/or geographic map boundaries. The goal of this report is to review current Quaternary-aged subsurface sediment modeling methods at the MGS and offer suggestions on how it can be improved in several fundamental ways: 1.) reduce errors in the final subsurface models that are artifacts of the modeling process itself; 2.) quantify uncertainty in modeling subsurface sand and gravel; and 3.) provide a work plan and method for subsurface models to remain current within shorter time frames as new data become available.This report reviews current subsurface unconsolidated sediment modeling methods at MGS to address how model application to regional investigations can be improved in several fundamental ways: 1.) reduce errors and redundancy in final subsurface models that are artifacts of the modeling process itself, including linearity along cross-section lines in both elevation and map unit extent, unintended gaps in map units between cross sections, and lithostratigraphic formation subdivision to accommodate sand bodies within formations ; 2.) quantify uncertainty in modeling subsurface sand and gravel; and 3.) provide a work plan and method for subsurface models to remain current within shorter time frames as new data become available.engroundwatersurficialmodelingQuaternarysedimentBonanza ValleyMinnesotaReport