The flow across the bottom face of the last node is

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Unformatted text preview: for every node in the MNW is written to this output file. If QNDflag = 0, then nodal flow information is not written, resulting in a smaller file. If QNDflag > 0, then the flow (L3/T) between the well node and the aquifer for all nodes of the MNW will be written (with a negative value indicating flow out of the aquifer and into the well). The additional data will not be written if the well contains only one node. QBHflag is an integer flag used to indicate whether additional flow information for the MNW borehole is written to this output file. If QBHflag = 0, then flows between adjacent nodes of the well are not written, resulting in a smaller file. If QBHflag > 0, then the flow between each well node in the borehole will be written (with a negative value indicating downward flow and a positive value indicating upwards flow). For each well node, the intraborehole flow across the top face (closest to the wellhead) of the node is recorded, where the flow is a volumetric rate (L3/T) within the borehole. The flow across the top face of the first node equals Qnet if the pump is located above the open interval. The flow across the bottom face of the last node is always 0.0, though this value is not printed. These data can be used to conveniently analyze or plot a profile of flows or velocities down a borehole. The additional data will not be written if the well contains only one node. 54 Revised Multi-Node Well (MNW2) Package for MODFLOW Ground-Water Flow Model CONCflag is an integer flag used to indicate what solute information for this particular multi-node well is written to its output file. Only specify if the GWT process is active. If CONCflag = 0, then in addition to the flow and head information, the concentration in the well will also be saved (see “notes” below for more details about the concentration value to be saved). If CONCflag = 1, then additional columns of information about mass flux will be printed. The mass flux removed from (or injected into) the ground-water system for the time increment and cumulatively will be written (these always equal 0.0 for a nonpumping well). Additionally, the mass flux into the well from the ground-water system during the time increment, the cumulative mass flux into the well, the mass flux out of the well and into the ground-water system during the time increment, and the cumulative mass flux out of the well will be written in successive columns. If CONCflag = 2, then concentration in the well and the calculated concentration at every well node are saved (but no data on mass flux are recorded). If CONCflag = 3, then all solute-related data are saved and written to the output file. Note 15: A unique unit number must be specified for each multi-node well listed in record 3 and matched to a DATA file type and file name in the MODFLOW name file. Note 16: For each well listed, the output file will record in tabular format the elapsed simulation time, the sum of all nodal inflows from the aquifer into the well (L3/T), the sum of all nodal outflows from the well into the aquifer (L3/T), the net flow rate into or out of the well at the wellhead (Qnet) (L3/T), the cumulative volume of flow into or out of the well at the wellhead over all time steps (L3), and the calculated head in the well (L). To this extent, the output file for each listed MNWOBS well is similar to that contained in the QSUM output file; however, the latter will contain information for multiple wells whereas the MNWOBS file will only contain information for a single well. Additional information on flows between the aquifer and the well at each node of the MNW will be written if QNDflag > 0. If the GWT process is active, then the solute information to be written is determined by the specification of CONCflag. The type of calculated concentration value for the well that is saved depends on the well flow. For withdrawal wells (Qnet < 0), the MNWI Package will record the calculated concentration in the well discharge. For high-rate injection wells (Qnet > 0 and no inflow at any nodes of the MNW), the MNWI Package will record the user-specified source concentration ( ). For nonpumping wells and low-rate injection wells (which include a mix of inflow and outflow nodes in the MNW), the MNWI Package will record the length-weighted average concentration in the borehole. Note 17: Although it is expected that a multi-node well will include more than one node in the grid, it is possible and allowable for a single-node well to be included in the list of multi-node wells read by the MNW2 Package. If a single-node injection well is specified for observation in the MNWI Package, then the software will simply record the user-specified source-fluid concentration, which is constant during a stress period. The software will not record the concentration in the aquifer; if those are desired, then concentrations calculated at specific nodes in the grid can be retrieved using the standard Observation Well (OBS) Package available for the MODFLOW–GWT model. Similarly, if a single-node withdrawal well is specified for observation in this package, then the software will record the values of aquifer concentration at the node corresponding to the location of this well [in this case, an identical record would be obtained using the OBS Packag...
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