Same question posted to MapHist with a good answer ... so forwarding ...
-------- Original Message --------
Subject: USGS Topos - Blue Line Stream Designations
Date: Wed, 30 May 2007 13:38:22 -0500
From: John B Conroy <[log in to unmask]>
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The USGS does not use the term "blue-line" because perennial and
intermittent streams are both shown in blue on USGS maps. Apparently,
the phrase "blue-line streams" is often used in legislation (usually
State) when USGS maps are used as guides for stream classification. The
author who coined the phrase was probably trying to distinguish streams
from the other black, red, and brown lines shown on USGS maps.
Unfortunately, the language has been copied by so many different States
without understanding the original meaning or the difference in
symbology between perennial and intermittent streams that the phrase may
be referring to perennial streams, intermittent streams, or both,
depending on how the law is written.
Although I don't think it has anything to do with the origunal use of
the phrase, I should point out that changes to stream channels were
shown in purple on photorevision maps because they were compiled from
imagery without any field classification. Also, although the USGS has
historically shown narrow intermittent streams and narrow washes with
the same blue symbol, there was a brief period of time beginning in 1971
when narrow washes in arid and semi-arid areas were sometimes shown with
a brown dash-dot or screened line symbol, but this practice conflicted
with the symbol book we used back then, so it may have been done
inconsistently or on comparatively few maps. Wide washes have always
been shown with a brown dot pattern on USGS maps in arid and semi-arid
areas.
The USGS does not claim any legal authority for the classification of
streams. However, most people consider our maps to be authoritative or
reasonably accurate, so we take care in trying to portray streams
properly. That being said, we like to remind people that stream
classification was a subjective process that was originally done in the
field during a limited time period and relied on observations and
information obtained from local residents. No scientific measurements
were made to determine the classification.
Our current definitions for perennial and intermittent streams are
available to be viewed by the public on our National Mapping Program
Standards web page at http://nationalmap.gov/gio/standards/. Scroll down
and click on "Primary Series Quadrangle Map Standards", and then click
on the pdf icon next to "Part 2: Hydrography, Standards for
1:24,000-Scale Digital Line Graphs and Quadrangle Maps" or go directly
to http://rockyweb.cr.usgs.gov/nmpstds/acrodocs/dlgqmap/2dqm0401.pdf.
The definitions for perennial and intermittent streams are located on
the first page of the STREAM template on page 2-231.
Back in the early 1980's, the USGS came out with a symbol set for new
maps and complete revisions that was a little easier to scan using the
equipment available back then. This symbol set, which came to be known
as Part 5 symbols, used solid lines with different line weights to
distinguish between perennial and intermittent streams. We continued to
use Part 6 symbols, which showed intermittent streams with a
dash-dot-dot-dot symbol, on revised maps. These days, we would use the
same symbol set on revised maps that was used on the previous edition of
the map, but with a new emphasis on generating new maps from current
data using internet-based tools, called /The National Map/, we have
virtually abandoned revising our old paper maps (http://nationalmap.gov/).
If you want to look at the Part 5 and 6 symbols, go to our standards web
site, click on the text next to the bullet for "Primary Series
Quadrangle Map Standards", scroll down the page to the table for the
"Standards for 1:24,000- and 1:25,000-Scale Quadrangle Maps", and click
on the pdf icon to the right of the text for the Part 5: or Part 6:
Publication Symbols.
I've posted a summary of how the USGS has shown hydrography over the
years that may address some of the other questions you may have on a
temporary ftp site at
ftp://ftpext.usgs.gov/pub/cr/mo/rolla/Standards/Hydrography/.
I hope this helps,
John Conroy
USGS/NSDI Standards Team
NGTOC III/Mid-Continent Mapping Center
1400 Independence Road, MS 523
Rolla, MO 65401
[log in to unmask]
Phone: (573) 308-3804
Fax: (573) 308-3652
__________________
----- Forwarded by John B Conroy/GIO/USGS/DOI on 05/30/2007 11:14 AM -----
*Dalia E Varanka/GEOG/USGS/DOI*
05/30/2007 08:57 AM
To
John B Conroy/GIO/USGS/DOI@USGS, Robert E Rinehart/GIO/USGS/DOI@USGS
cc
Subject
Fw: [MapHist] USGS Topos - Blue Line Stream Designations
the only reply so far to the previous message.
----- Forwarded by Dalia E Varanka/GEOG/USGS/DOI on 05/30/2007 08:57 AM
-----
*Joel Kovarsky <[log in to unmask]>*
Sent by: [log in to unmask]
05/29/2007 05:18 PM
Please respond to
Discussion group for map history <[log in to unmask]>
To
Discussion group for map history <[log in to unmask]>
cc
Subject
Re: [MapHist] USGS Topos - Blue Line Stream Designations
This is a MapHist list message (when you hit 'reply' you're replying to
the whole list)
o + o + o + o + o + o + o + o + o + o + o + o + o + o + o + o + o + o + o +
I am not sure if this will help, but there are several tables for
perennial and intermittent streams (on topographic maps) dealing with
"standards for inclusion" in the following article:
The Professional Geographer
Volume 26 Issue 1 Page 34 - February 1974
To cite this article: Robert R Drummond (1974)
/WHEN IS A STREAM A STREAM?/
The Professional Geographer 26 (1), 3437.
doi:10.1111/j.0033-0124.1974.00034.x
Joel Kovarsky
A'Hearn, William wrote:
> This is a MapHist list message (when you hit 'reply' you're replying
to the whole list)
> o + o + o + o + o + o + o + o + o + o + o + o + o + o + o + o + o + o
+ o +
>
> Does anyone know what is (was?) the criteria used by USGS to
delineate a "BLUE-LINE" stream on USGS topo maps? We have searched
through USGS's website and Googled it to no avail.
>
> Thanks in advance,
>
> -- Bill A'Hearn
>
> Ø Ø Ø Ø Ø Ø Ø Ø Ø Ø Ø
>
> Bill A'Hearn, LSIT
> GIS Analyst/Mapping Specialist
> PW Engineering
> Mapping & GIS Services
> City of Glendale, CA
> [log in to unmask]
>
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