Server River Center

This interface is used to choose which size (order) rivers/streams to import from the MAGNET Data Center, to assign attributes to the imported features, and to control the display settings (stream order color and line thickness).

Data Source

There are two processed datasetes available for stream import:
1) USA NHDplus - National Hydrography Dataset Plus High Resolution for the United States (including Hawaii, Peurto Rico, and portions of Alaska). Invalid stream geometries have been fixed in the processed dataset. Link to USGS site.
2) Global Hydroshed - HydroRIVERS network of all global (US and elsewhere) rivers that have a catchment catchment area of at least 10 km² or an average river flow of at least 0.1 m³/sec, or both. HydroRIVERS has been extracted from the gridded HydroSHEDS core layers at 15 arc-second resolution. Again, invalid stream geometries have been fixed in the processed dataset. Link to HydroSHEDS site.

Stream Orders

A series of checkboxes are available to choose which order(s) of streams to import into the model.

Stream orders are used to classify streams by size, ranging from the smallest 1^st- (and "zero-th"-) order streams to the largest 10^th-order streams and rivers (in some areas, the largest stream order is less than 10; for example, 6^th order streams are the largest order found in Michigan, USA).

When modeling at large scales(e.g., watershed or basin), the impacts of 1^st/0^th and 2^nd order streams is typically small, so the default setting in IGW-NET is to only import 3^rd-10^th order streams.

Drawing Options (Conceptual vs. Server-based)

Users can control the line color and and line thickness (pixel size) of any of the stream orders imported into the model.

Note that the number of stream segments being imported into the model impacts how they are displayed. If the number of segments is less than the threshold (currently 8,000 ), the streams are treated as 'conceptual line features' and are automatically shown in the display, using the current set of drawing options (color, line thickness), when the user adds the conceptual image (CnptImage) overlay:
Other Tools > Utilities > Overlay CnptImage > Overlay

If the user updates the color and/or thickness of one or more orders when streams are treated as conceptual line features, the model must be re-run before the updated settings are available in the display.

If the number of stream segments is greater than the threshold, then they are treated as 'server streams' and will only be shown in the disply then the user selects the suboptions from the CnptImage menu:
Other Tools > Utilities > Overlay CnptImage > check 'Server Streams' box

If the user updates the color and/or thickness of one or more orders when streams are treated as server streams, the model does not have to be re-run before the updated settings are available in the display; simply make the changes in this interface, and then uncheck and check the 'Server Streams' option in the Overlay CnptImage menu.

Order-based Attributes

This is the first (default) option for assigning attributes to the imported rivers. The lookup table allows for assigning the following properties based on the order of the imported feature:

• Leakance - the ratio: (riverbed sediment conductivity / riverbed sediment thickness) x river width [units of L/T, e.g., m/day].

• Two-way One-Way - option to define the rivers as a i) one-way head-dependent boundary condition (aquifer loss as surface seepage only); or ii) two-way flux boundary condition (water or enters or leaves the aquifer depending on the head gradient.

• Depth - average river depth [units of L, e.g., m].

• Width - average river width [units of L, e.g., m].

• Manning - manning roughness coefficient (used in channel flow modeling; presently not available in IGW-NET); typically smaller for larger streams/rivers.

• Order Name - the conceptual feature name assigned to all river/stream segments of the order. The flux into and out of the model is grouped according to these different orders when displaying water-balance information.

• Alias Name - is name given to the imported features that will appear when editing the polyline attributes (Name: ... in the Line Attributes menu).

Constant Attributes

You can assign the same attributes to all stream orders by choosing the radio button next to 'Constant'. Be default, all orders are given a leakance of 5 1/m, but you can use the provided text field to update this. You can also define a bottom elevation calculated as the river stage minus some value (default: 3.3m) by checking the box next to 'Bottom=Stage-'.

Other assumptions are made when using this option. For example, the rivers are assumes to be a two-way head-depedent boundary condition, a depth and width is assumed, and the Order / Alias Name is assumed to be Stream.

Other Options

TopE as Stage/Drain Bottom

By default, the stream/river stages are extracted from the Top Elevation (TopE) data, or the Digital Elevation Model (DEM) (hence, the checked box next to 'TopE as Stage/Drain Bottom). This is also the case when modeling the streams/rivers as a one-way drain (surface seep).

To assign different stage values, consider drawing a river feature, or using the 'Line from a shapefile' tool (Conceptual Model Tools > Lines > Lines from a Shapfile).

Allow to add recharge to RIV cell

Recharge is typically added to every cell of the top-most layer of a IGW-NET model as an input (source) of water. By default, if that cell contains a river/stream, recharge is no longer applied to that cell. Check the box next to 'Allow to add recharge to Riv cell' to disengage this default setting).

RIV cell overrides DRN cell

Often, users will treat the entire land surface within the modeal as a 1-way drain. However, some parts of the model should not be treated this way if the river is already accounted for; therefore, the default setting is to ignore the drain calculation when a cell contains part of a river/stream (hence, the checked box next to 'RIV cell overrides DRN cell'). (This box can be unchecked if the land surface is not being treated as a drain).