BASINS2: Using the QUAL2E Model
Prepared by Ann Quenzer, Dr. Neal Armstrong, and the USEPA
Table of Contents
Goals of the Exercise
This exercise is structured after the EPA BASINS Training Workshop for
BASINS2 training.
This exercise will familiarize the user with the tools available in
BASINS. The exercise shows how the QUAL2E model works using Onion Creek
Watershed in Texas. For your reference, Onion Creek is a tributary of the
Colorado River which is located in the south end of Austin, TX. The objective
of the model is to model the nitrogen cycle. the phosphorus cycle, and
COD within the river reaches. The exercise will also model Total Suspended
Solids.
Computer and Data Requirements
ArcView 3.0a and BASINS2 software are needed for the exercise.
The data needed for the exercise is included in the Basins directory on
the C:\ drive of the computer. It is also downloadable from the EPA Internet
Site: http://www.epa.gov/OST/BASINS/.
Three computers in the last row of room 3.400 in the LRC are setup
with ArcView 3.0a and BASINS2. There is also one computer set up in room
3.402 in the LRC and one computer at CRWR. If you would like the software
installed on your computer at home, the BASINS software is downloadable
through the EPA Internet site (http:\www.epa.gov/OST/BASINS).
The computer requirements needed to run the BASINS software are listed
below:
Computer Pentium w/ CD-ROM
RAM 32 MB
Free disk space 400 MB for an average State
Operating System Windows 95 or Windows NT
GIS software ArcView 30.a
If you are running WindowsNT you will need a special build.apr file
in order to run the system.
Getting Started
Using the Windows Start button, click on the Programs
icon which will lead you to the Basins program. Click on the Basins
icon. Open the project called texas.apr.
In order to get the texas.apr project, a data extraction must be done
along with the build program. These two process are explained in the BASINS
users manual. They are not discussed in this exercise due the time involved.
** Immediately save the project to a directory of your own with
a unique name.**
The BASINS program saves to its own folder as the default. This means
that other people have access to your files which are created while you
work. You will not have the option to save most of your data files else
where, but you will have the option to save your project to where you want
it. This will partially secure your project as you own. The reason for
this is because the version of BASINS that we are using is still in Beta
format and some of the bugs have not been worked out.
Data Preparation in Basins
- Make the Basins View active. Display and activate the Reach
File theme.
- From the Theme menu, select Query. Locate the following
reaches by double clicking on the field Rivrch and the following
reach.: 12090205002, 12090205003, 12090205004, and 12090205005.
Your query will look something like this {Rivrch = "12090205002"
or Rivrch = "12090205003" or Rivrch = "12090205004"
or Rivrch = "12090205005"}. This is part of Onion Creek
within the City of Austin TX.
- From the Models menu, select QUAL2E.
- Select 1993 as the point source discharge year.
- You will then be informed by a message box that COD and the nitrogen
and phosphorus cycles will be modeled as defaults.
- Next, you will be prompted to select up to 3 conservative substances
and 1 nonconservative substance. The numbers in front of the substance
name indicate the number of dischargers in the
selected reaches and the total number
of pounds discharged per year. On the “Select 1st conservative
constituent” screen, select Solids, Total Suspended. Click OK.
You can make the message box bigger to read the list better.
- Click CANCEL when prompted for a second conservative substance.
- Click CANCEL when prompted for the nonconservative substance.
- Read the message on the following screen on how to load the the BASINS-built
input file (QUALINP.RUN) in QUAL2E. Click OK.
NOTE: If others have run Qual2E on the same machine before you
have, the input file will be over-written. As a curtousy to others, save
your input and output files to a disk or your individual workspace and
delete these files when you are finished with this exercise. Output files
will be named with an .out extension or a .q2e
extension in the basins/modelout/ folder. The input file has an
.run extension in the models/qual2e/
folder. Be careful what you delete so that you
do not delete any program files or other important files.
Using Qual2E
- Once the QUAL2E windows interface appears, select the Import menu
and choose Run file. Recall the name of your input file is QUALINP.RUN.
Select this file. Performing this action loads data from BASINS into QUAL2E.
- Click on the Index button and select the “Screen 2” button
to jump to Stream Reach System screen. Note that RF1 reach numbers
appear in the Reach Name column. QUAL2E uses its own numbering in the left
column (i.e. 1, 2, 3 … etc). Write original RF1 reach numbers (CUSEG) and
corresponding QUAL2E reach numbers for future references.
- Click on the Index button and select “Screen 11” to enter
hydraulic data. Data elements, except for Manning’s roughness coefficient,
in the Hydraulic Data screen are not available from RF1 database. Therefore,
you will have to supplement the data from other sources. Calculate the
depth versus flow and velocity versus flow relationships as shown in class.
- Look at all of the "Screens" to see if the numbers
make sense. Use the Next, Back or Index buttons to
move from screen to screen.
- In the last screen, click on Run to execute the model.
- Click on the Yes button when you are asked if you want to view
the model output. It will display the model output using a text editor.
Check to make sure all of the output makes sense. Close the window when
you are done.
- Click the Graphics button to begin the plotting program. Click
the REACHES button. This screen displays the reach network and the
computational elements used for the simulation. Note the locations of point
sources.
- Click File and Exit to exit this screen.
- Select 1 as Starting Reach and 3 as Ending Reach. Note
that the Flow versus Distance option is selected as the Type of
graph.
- Click the Run button and press OK to accept that the
plot will be saved as the selected file. The graph shows a plot of flow
versus distance.
- Next, plot water quality constituents versus distance.
- Select 1 as Starting Reach and 4 as Ending Reach in the
first graphics screen.
- Select the Water Quality Constituents versus Distance option
selected as the Type of graph and click the Next button.
- Select Biochemical Oxygen Demand and Dissolved Oxygen by
holding the shift key and clicking the mouse.
- Click the Run button and press OK when you are asked
to confirm the filename in the Graphics Selection screen.
- You can also plot the conservative constituent.
- Close the plot window when you are done.
- Also close the QUAL2E Graphics window.
Answer the following questions:
- Do you see three jumps in the plot in the flow vs. distance plots?__________________________
- What contributes to the increase of stream flow at these three locations?
______________________
- What is accountable for the changes in slope in the constituent plots?____________________
Working with Qual2E
- To determine what facilities are discharging to one of the four stream
segments modeled, click on the Index button in the QUAL2E window
and click on the Screen 17 button to go to the Point Loads and
Withdrawals screen.
- There are six dischargers listed. Two items actually indicate that
four dischargers are combined in each of the elements. QUAL2E allows only
one discharger in a computational element (refer to Screen 3). Therefore,
if there are more than one facilities discharging to a computational element
of a reach they must be added and the total flow and loads are considered
as point source contributions to the reach.
- Open BASINS View in ArcView.
- Activate Permit Compliance System theme and click on the Open
Tables button,
.
- Do a query to find the facilities that discharge into CUSEG 12090205002,
12090205003, 12090205004, and 12090205005. Note the facility
names and mile points. In some cases mile points of facilities are missing
in the PCS database and the mile point field contains 0.0 miles.
- Update the mile point information of the facilities in QULA2E. Find
the length of each computational element (Screen 3, Computational Element).
- Calculate the computational element that each of the dischargers should
be in.
- In the Computational Element screen change the type to P
for any elements that have missing dischargers. Also change any elements
from P to S that have too many dischargers.
- Now go to the Point Loads and Withdrawals screen and you may
see blank lines at the bottom of the table.
- Substitute 4 Disch. with a less number of facilities that are dischaging
to that element, if there are less dischargers at that element. Also change
the amount of discharge to that element, if it is known.
- Type the facility name in the blank line. Assume that the point source
discharge information for any new discharges are as follows: Treat (%)
0.0 Flow (m 3 /s) 0.5 Temp ( o C) 23.0 DO (mg/L) 5.2 BOD (mg/L) 3.0 Soli
(mg/L) 40.0 NH3-N (mg/L) 0.0 Type 0.0 for all other parameters.
- Save the project.
- Run the model and plot graphs to view results.
- To determine if you are modeling mean flow, low flow or another flow
condition, open Screen 16, Headwater Source Data, in QUAL2E
and write Headwater Names and corresponding flow values
(note the units).
- Open BASINS view in ArcView and activate the Reachfile 1
theme.
- Select the inquiry tool, and click on the reaches you are simulating
in QUAL2E.
- Write MNFLOW and SVTNFLOW values of each reach. These
flow values are in cubic feet per second. Convert them to m 3 /s by dividing
the numbers by 35.3.
- Now compare these numbers with flows listed in Headwater Source
Data screen of QUAL2E.
- Substitute flows in the Headwater Source Data screen
with mean flows you read from BASINS ArcView and converted to m 3 /s.
- Run QUAL2E for mean flow condition and view the graphs.
- Change BOD of reach 12090205004 to 26 mg/L in Screen 14,
Initial Conditions of the Stream.
- Run the model and view graphs.
- Double the flow from one of the sources in the Point Loads
and Withdrawals screen.
- Run the model and view graphs.
Answer the following questions:
- List the six dischargers according to QUAL2E.___________________
- What are the discharge locations (mile point) of the facilities discharging
to each reach?
- If the initial concentration of BOD in reach 12090205004 is
26 mg/L, what is the impact on model results?
- If the Griffin facility doubles its current discharge, what happens
to DO and BOD concentrations in the stream?
Visualization of Qual2E
In BASINS View, pull down the MODELS menu and select VISUALIZE.
Choose QUAL2E Output File in the output file type selection dialog
box.
Specify the QUAL2E output file name in the file selection dialog box.
The QUAL2E output files are located in the \BASINS\MODELS\QUAL2E directory.
There are two QUAL2E output files. Both have the same name as the QUAL2E
input file (e.g., QAL2E002.INP), but each has a different extension. The
summary output file has an OUT extension, which is displayed after each
simulation run within the QUAL2E interface. The other output file has a
DOU extension (e.g., QAL2E002.DOU), and it is used in the
QUAL2E output visualization process. Therefore, in the file selection dialog
box you will prompted to choose only the DOU file.
Click on OK after you have selected the output file name.
Select the output element you want to visualize in the dialog box.
The next dialog box asks whether you want to use previously saved ranges
to group results for visual display. If you want to use an existing scheme,
click on YES and you will be asked to specify the name of the scheme. Click
on NO if you do not have any.
From the Classification Scheme Definition box, you can select
default settings of classes, modify default classes, or edit previous settings
of the saved schemes.
The next dialog box gives you the option to save the current settings
of the classification scheme for future use. If you do not want to save
then, click on NO. Otherwise, click on YES and you will be prompted
to provide a name for the scheme.
The Visualize screen displays the color-coded reaches that were included
in the QUAL2E simulation. One of the two windows has the banner QUAL2E:
F=filename, output element name (e.g., Biochemical Oxygen Demand). Notice
that the new active theme includes the selected output element name and
the legends for the classification scheme. You can double-click the left
mouse button on the window banner for a full screen view. You might want
to check the Reach File,V1 theme to view other reaches in the cataloging
unit. Other themes can be viewed to examine related information with the
model visualization.
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