Gutters
=======

Overview
--------

In the FLO-2D model, street gutters convey shallow flow using a typical
curb and gutter cross section that has a triangular shape created by the
cross slope associated with the street crown. For the FLO-2D gutter
routing, the triangular flow area is assumed to have a 2 percent from
the middle of the street to the trough of the gutter. The gutter flow is
exchanged with other upstream and downstream gutter elements, the
sidewalk, and other street elements (not having a gutter). Floodplain
flow is exchanged with the gutter elements through the sidewalk
interface. See the FLO-2D Reference Manual for more information on using
the Gutter component with FLO-2D.

Digitize or Copy Data
---------------------

1. Select the layer or the Gutter Line Layer and click Toggle
   Editing. Create polygons or polylines that represent the gutter
   alignment. Enter the data from the attributes table. Save the Gutter
   layer and close the editor.

.. image:: ../../img/115-Gutters/gutters1.png


Sample Data
-----------

2. Click the Sampling Gutter Values button in the Grid Tools and click
   OK when the process is complete. Fill the Global values and click
   OK to close the global data.

.. image:: ../../img/115-Gutters/gutters2.png

.. image:: ../../img/115-Gutters/gutters4.png


Export Data
-----------

5. It is not necessary to turn on a Gutter Switch. If the GUTTER.DAT
   file is in the project folder, Gutters will be applied. Simply delete
   or rename the file to turn them off.

.. image:: ../../img/115-Gutters/gutters5.png

.. image:: ../../img/115-Gutters/gutters7.png



Troubleshooting
---------------

1. Create the gutter polygons or gutter polylines if they are missing
   from the Gutters Areas layers.

.. image:: ../../img/115-Gutters/gutters8.png
 

2. If the Grid layer is empty,
   create a grid and try again.

3. If a Python error appears during the sampling process, the attribute
   table may be missing. Save and reload the project into QGIS and try
   again.