The Basic 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 specify properties of streams that do not vary with time.
Each stream segment must have a unique segment number (NSEG). However, it is OK to skip numbers when assigning values of NSEG because ModelMuse may renumber them ensure that they meet the input requirements of MODFLOW. The segment numbers will be renumbered if the segments are not numbered consecutively starting at 1.
Reach length (RCHLEN)
RCHLEN is the length of channel of the stream reach within the model cell. The length of a stream reach can exceed the model cell dimensions because of the meandering nature of many streams. The length is used to calculate the streambed conductance for this reach. Also, the sum of the lengths of all stream reaches within a segment is used to calculate the average slope of the channel for the segment and subsequently other values, such as the elevation of the streambed and stream stage. The default formula for RCHLEN, "ObjectIntersectLength," gives the length of the portion of the object that intersects the model cell.
In MODFLOW-LGR models, RCHLEN is adjusted in child models in cells containing shared nodes. The entire length of the reach in the parent model is allocated among the reaches in the corresponding cells of the child model. The segment containing the reach in the parent model will be deactivated by MODFLOW-LGR after the first iteration.
Streambed top (STRTOP)
STRTOP is the top elevation of the streambed.
Stream slope (SLOPE)
SLOPE is the stream slope down the length of the reach.
Streambed thickness (STRTHICK)
STRTHICK is the thickness of the streambed.
Streambed Kv (STRHC1)
STRHC1 is the hydraulic conductivity of the streambed.
Saturated volumetric water content (THTS)
THTS is the saturated volumetric water content in the unsaturated zone.
Initial volumetric water content (THTI)
THTI is the initial volumetric water content. THTI must be less than or equal to THTS and greater than or equal to THTS minus the specific yield defined in either LPF or BCF.
Brooks-Corey exponent (EPS)
EPS is the Brooks-Corey exponent used in the relation between water content and hydraulic conductivity within the unsaturated zone (Brooks and Corey, 1966).
Max unsaturated Kz (UHC)
UHC is the vertical saturated hydraulic conductivity of the unsaturated zone.
This variable can only be specified if the user (1) chooses to specify some streambed properties by reach, (2) chooses to simulate unsaturated flow, and (3) chooses not to use the value of Kz from the LPF or BCF packages on the SFR: Stream-Flow Routing package pane of the MODFLOW Packages and Programs dialog box. By specifying a formula that will give different results in different cells, the variable can vary down the length of the segment.
