Hi, this is Megan Poff
and I'm the Field Office Chief
at the USGS in Las Vegas, Nevada.
In this video, I'll be discussing how to input data
into a program called SAC-GUI
to plot high water marks and view
high-water mark profiles in the field,
steps that are required
for most indirect measurement techniques.
There are other programs you can use
to plot high-water marks in the field,
but I've found SAC-GUI to be the most straightforward.
I should mention as a caveat here
that SAC-GUI is no longer supported
and may stop working at some point,
depending on the user's operating system.
In the event that SAC-GUI does not work,
analysts can use iRIC SAC, the replacement for SAC-GUI,
although it's currently
not as user-friendly for field plotting.
Before you even go to the field
and survey any type of indirect measurement,
make sure you have SAC-GUI on your computer.
You can download it at
https://water.usgs.gov/software/SAC/.
We're now in the field
and have surveyed all the high-water marks.
If you surveyed the high-water marks
in Cartesian coordinates, i.e. northings and eastings,
all you have to do is export your data
as either a tab, comma, or space-delimited ASCII file
from the data collector and put the file on your computer.
I typically will export files as .csv files
so I can easily edit or manipulate them
using a program like Excel prior to importing to SAC-GUI.
If you surveyed the high-water marks in polar coordinates,
i.e. angles and distances,
you will need to convert the angles and distances
into northings and eastings first.
This is discussed in the SAC conversion spreadsheet video.
SAC-GUI has some specific naming formats
for all surveyed objective points and high-water marks.
I'm going to check over my file
and make sure I'm following the format first.
More information on the naming formats can be found
at the SAC-GUI factsheet FS 2012-3112.
The objective points can be called BM, RM, or HUB,
then a dash, then a number.
For example, we should see things like RM-5 and HUB-1.
If you have other things in your file,
just remove them for now.
High-water marks are either LH or RH
for left or right high-water mark,
a dash, a number, and an optional second dash and quality.
For example, you could have RH-3-G or just RH-3.
I encourage you to include the optional quality code.
I'm now going to finish my file
by removing any extra columns and column headers,
and adding in a column
that will serve as a sequence identifier.
Each point must have its own unique number.
Now I'll hit save, and say yes
when Excel complains about the .csv format.
Let's crank open SAC-GUI and get started.
Click Maximize on the upper right of the screen
so you don't lose buttons later on.
We'll use the New Indirect Wizard
to get the data into the SAC-GUI.
Click File, New Indirect.
The first screen that opens up is the Project Info screen.
Because we're just using this program
to quickly plot high-water marks in the field,
you get to skip filling anything out on this screen.
Hurray, click Next on the bottom right.
The following screen is the Survey Data Input screen.
Click Browse on the upper right to navigate
to wherever you saved your file.
Once you find the file, you can either double-click it,
or single click and then click Open.
The program is now asking me for a delimiter.
My file is comma-delimited, so I'll pick that.
The data should now be arranged in columns for you.
Click the appropriate header for each column.
In my file, the first column is the sequence number,
so I'll leave that as selected.
For the next few columns, I always export my data as NEZ,
meaning northing-easting-elevation.
I'll change the column headings to reflect that.
Keep in mind that SAC-GUI defaults
to show easting and then northing.
It actually can't determine which of your columns
is easting and which is northing,
that is just the default display order.
If you export in NEZ like I do,
make sure you have your columns set correctly.
The next column is already set to point ID,
and the final column contains any remarks.
Click Next on the bottom right.
We're now at a Review/Edit Data screen.
If anything is immediately wrong with your data,
SAC-GUI will highlight the field in red.
My data is fine though,
so I'm going to click Next on the bottom right.
This is the Plan View Plot screen,
and what we do here is define a baseline
so the program knows where downstream is
and where the centerline of the channel is
so all the points will plot properly.
Click Add Baseline in the lower right.
I'm going to click on the screen
to define my upstream and downstream baseline points,
making sure I follow the shape of the flood channel
and I define the baseline upstream and downstream
of the extent of my data, that is,
beyond any high-water marks surveyed
at the upstream and downstream end of the reach.
If the legend is in the way,
you can easily right click and remove it.
You can also zoom in or out
by right-clicking and choosing Zoom In or Zoom Out.
Next, tell SAC-GUI which baseline point
is the downstream point by clicking in the box.
Hit Save.
You should now have a baseline with numbers
appear in the Plan View Plot.
If you don't see the baseline, or if you get an error,
double-check that your baseline extends upstream
and downstream of your data.
You may need to zoom out to help with this.
Once you see the baseline with numbers on it,
click Next on the lower right.
Ta da, it's the High Water Marks Profile plot!
I can use this to easily view
where to place cross sections for slope-area measurements.
The plot defaults to showing both the left
and right bank high-water marks on one screen,
but you can also use this plot to view and delineate
left- and right-bank high-water marks separately.
This will give us more information about slope breaks
in the water-surface profile
and where best to place cross sections.
Cross sections should be placed at those breaks
as discussed in the slope-area videos.
The SAC-GUI plotting tool
is also good for other indirect methods,
including contracted-opening measurements,
to plot water-surface approach profiles,
and culvert measurements, to plot approach profiles
and evaluate ponding upstream from the culvert.
If you are surveying a slope-area measurement,
write down the high-water marks at or near their locations
where you'd like to place cross sections,
and save your SAC-GUI project
for reference back in the office.
When you start surveying again,
you can use the stake-out function
on your surveying instrument
to have it lead you straight to the points
where you've decided to place your cross sections
based on the high-water mark profile plot.
If you need help in the field,
call your supervisor, surface-water specialist,
or indirect measurement specialist.