MODFLOW 6 model of two hypothetical stream-aquifer systems to demonstrate the utility of the new Mover Package available only with MODFLOW 6

Two MODFLOW 6 (version 6.2.1) models of hypothetical stream-aquifer systems are presented for the demonstration and utility of the Water Mover (MVR) Package available only with MODFLOW 6. Using a generalized approach, MVR facilitates the transfer of water among many arbitrary combinations of simulated features (i.e., pumping wells, stream, drains, lakes, etc.) within a MODFLOW 6 simulation. In this archive, the nature of the two hypothetical models are (1) simple ("model1" in the model.zip file) and complex ("model2" in the model.zip file). "Model1" relies on a previously published parent-child nested grid simulation (see "example 3" on page 30 at https://pubs.usgs.gov/tm/6a44/) that has been refactored for MODFLOW 6. In the accompanying journal article, this model is described in the supplemental material. The child model resolves the parent model grid cells with 27 (3x3x3) additional cells. Model1 uses only two MVR connections to pass water (1) from a streamflow routing (SFR) reach in a parent model to an SFR reach in a child model and (2) from an SFR reach in the child model back to an SFR reach in the parent model. The complex model has 64 rows, 133 columns, and 4 layers and is patterned after an irrigated river valley in the semi-arid western U.S. "Model2" first appeared in the journal article, https://www.sciencedirect.com/science/article/pii/S136481521630113X. In the journal article accompanying this data release "model2" is discussed in the section titled "A Mock Irrigated River Valley". The model demonstrates the general flexibility of the MVR package so readers can get a sense how MODFLOW 6 may be tailored to complex water-management problems in conjunctive-use systems. To this end, thousands of MVR connections are present with every stress period. The complex model simulates a hypothetical water-year and therefore relies on 366 transient (daily) stress periods after the initial steady-state stress period. The transient period of the model extends from an arbitrary October 1st to the following September 30th. The complex model includes a river, 4 main diversion ditches, and numerous tributaries, many of which are open drains representative of irrigation return flows. All these features are represented with the streamflow routing (SFR) package. The simulation also includes a reservoir represented with the Lake (LAK) package. Rainfall and evapotranspiration are simulated with the unsaturated-zone flow (UZF) package. Water transfers between packages are handled by the MVR package. This USGS data release contains all the input and output files for the simulations described in the associated journal article.