Flows Tab

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This tab is on the SFR: Stream-Flow Routing package pane of the MODFLOW Features tab of the Object Properties dialog box. It is used to define how much water enters or leaves the stream by processes other than interaction with groundwater.

The Starting time and Ending time of each time period is specified on the Time tab

Flow into upstream end (FLOW)

FLOW is the streamflow (in units of volume per time) entering or leaving the upstream end of a stream segment (that is, into the first reach).

•If the stream is a headwater stream, FLOW defines the total inflow to the first reach of the segment. The value can be any number ≥ 0.

•If the stream has tributaries, FLOW defines additional specified inflow to or withdrawal from the first reach of the segment (that is, in addition to the discharge from the upstream segment from which it receives flow). This additional flow does not interact with the groundwater system. For example, a positive number might be used to represent direct outflow into a stream from a sewage treatment plant, whereas a negative number might be used to represent pumpage directly from a stream into an intake pipe for a municipal water treatment plant.

•If the stream is a diversionary stream, and the diversion is from another stream segment, FLOW defines the streamflow diverted from the last reach of stream segment IUPSEG into the first reach of this segment. The diversion is computed or adjusted according to the value of IPRIOR.

•If the stream is a diversionary stream, and the diversion is from a lake, FLOW defines a fixed rate of discharge diverted from the lake into the first reach of this stream segment (unless the lake goes dry) and flow from the lake is not dependent on the value of ICALC. However, if FLOW = 0, then the lake outflow into the first reach of this segment will be calculated on the basis of lake stage relative to the top of the streambed for the first reach using one of the methods defined by ICALC.

Precipitation rate (PTSW)

PTSW is the volumetric rate per unit area of water added by precipitation directly on the stream channel (in units of length per time). The total volume of water added will be the precipitation rate times the reach length times the channel width.

Evapotranspiration rate (ETSW)

ETSW is the volumetric rate per unit area of water removed by evapotranspiration directly from the stream channel (in units of length per time). ETSW is defined as a positive value. The total volume of water removed will be the evapotranspiration rate times the reach length times the channel width.

Runoff volume (RUNOFF)

RUNOFF is the volumetric rate of the diffuse overland runoff that enters the stream segment (in units of volume per time). The specified rate is apportioned to each reach of the segment in direct relation to the fraction of the total length of the stream channel in the segment that is present in each reach.