Surface Water Information--Data Scripts

Shiftcheck

Name:
Shiftcheck-Identify potentially problematic shifts and report on their prevalence.

Information:

This review script scans all available shift curves for the period of water years specified by the user and counts the number of occurrences of ,and specifically identifies the station ID and date of entry of, the following shift curve types (also see explanation in example output):

Single Point Shifts – for example: 3.00, +.20

Multi-point shifts with open high end – for example: 1.50, +.21; 2.50, +.31; 5.00, +.67

Shifts that cross zero – for example: 1.50,-.21; 2.50, +.13; 6.00, 0

Shifts with obviously bad slopes – slopes less than or equal to -1 where slope is computed as shift difference/gage height difference of each input point.

Shifts with questionable slopes – slopes greater than or equal to 1.50 or between -0.67 and -1.00, where slope is computed as shift difference/gage height difference of each input point.

Most of these types of shifts can be valid shift curves under some circumstances, but at least require the correct documentation and explanation of the conditions. These types of shift curves have often been found to be misapplied to control conditions that don’t warrant them, are being applied due to a poor base rating curve, or haven’t had adequate documentation to verify that they are being applied correctly.

Having none of these types of shifts show up in this report should not necessarily be a goal, as the conditions that can lead to many of these types of shift curves are not entirely uncommon. Care should be exercised with their application, ensuring that base rating curves shouldn’t be redrawn or that control conditions warrant their application and that those conditions are well documented within station analyses, field notes, etc… For a good summary of conditions under which these shift curve types may be valid, please review Rantz, Vol.2 Ch. 10 p. 344-360 and 385-387 and Kennedy, p25-26.

Script prompts user for beginning and ending water years if not supplied on the command-line and then scans all shift curves found on the server during and between those years. The results are output in file shiftcheck.NWISHost.beginWY.endWY.report.

where "NWISHost" is the name of the NWIS machine being used
"beginWY" and “endWY” are the beginning and ending water years specified by the user for retrieval

USAGE: shiftcheck [beg_water_yr] [end_water_yr]

Where:

: beg_water_yr = First water year to start scanning for problematic shift curves
end_water_yr = Last water year to start scanning for problematic shift curves

Example Output:

Summary of stations with potential stage-discharge shift problems

NWIS host nwisvatest1
Period run - water years 2006 to 2006

-----------
Explanation
-----------

Single point shifts - hopefully this one is obvious!
 
Multi-point shifts with open high end - A two or three point shift with the highest point non-zero. The shift point listed in the details is the highest point.

Shifts that cross zero - A shift that goes from one side of the zero shift to  the other. The shift point listed in the details is the higher point.

Shifts with bad slopes - A shift that has a slope (shift diff / GH diff)  greater than or equal to -1.0. The shift point listed in the details is the higher point.

Shifts with questionable slopes - A shift that has a slope greater than 1.5 or between -0.67 and -1.00. The shift point listed in the details is the higher point.

A given shift can be listed twice if it falls under more than one category, or twice in the same category if it crosses zero twice.

-------
Results
-------

  1377  Total shifts checked
     8  Total single-point shifts (1 percent)
   215  Total multi-point shifts with open high end (16 percent)
    99  Total shifts that cross zero (7 percent)
     3  Total shifts with bad slopes (0 percent)
    18  Total shifts with questionable slopes (1 percent)

-------
Details
-------

  **** NOTE ALL SHIFTS REPORTED IN GMT TIME ****

  SINGLE POINT SHIFTS

STATION           DD  RAT    START_DT_TM           SEQ  STAGE     SHIFT
---------------   --  ----   -------------------   ---  -------   -------
06119600          2   1.1    2006-09-04 23:15:00   1    2.000     .029
06119600          2   1.1    2006-09-06 21:00:00   1    2.000     .029
06137400          1   8.1    2005-10-04 17:47:00   1    1.129     .029
06183450          1   9.0    2005-12-06 19:10:00   1    2.170     0.189
06183450          1   9.0    2006-01-24 17:15:00   1    2.259     0.100
06183450          1   9.0    2006-04-05 05:58:00   1    2.259     0.100
06212500          1   20.0   2005-10-01 06:00:00   1    2.859     .079
12365000          3   8.0    2006-02-17 19:00:00   1    1.000     0.100

  MULTI-POINT SHIFTS WITH OPEN HIGH END

STATION           DD  RAT    START_DT_TM           SEQ  STAGE     SHIFT
---------------   --  ----   -------------------   ---  -------   -------
06006000          2   2.0    2006-04-01 07:00:00   2    4.449     -0.100
06006000          2   2.0    2006-05-16 18:00:00   2    4.449     -0.100
06019500          1   11.0   2005-10-04 18:00:00   2    4.699     0.159
06019500          1   11.0   2006-04-12 18:00:00   2    4.699     0.159
06019500          1   11.0   2006-05-16 18:00:00   2    4.699     0.100
06019500          1   11.0   2006-05-21 21:00:00   2    4.099     -0.100
06019500          1   11.0   2006-06-26 18:00:00   2    4.099     -0.100

  SHIFTS CROSSING ZERO

STATION           DD  RAT    START_DT_TM           SEQ  STAGE     SHIFT
---------------   --  ----   -------------------   ---  -------   -------
06077200          2   2.0    2005-10-05 18:00:00   2    4.250     -0.100
06085800          1   8.0    2006-04-01 07:00:00   2    5.699     -0.280
06085800          1   8.0    2006-04-14 18:00:00   2    5.699     -0.280
06088500          2   10.0   2005-11-30 19:00:00   2    4.800     0.200
06092600          1   7.0    2006-04-01 07:00:00   2    1.500     0.150
06092600          1   7.0    2006-05-21 22:00:00   2    1.500     0.150
06092600          1   7.0    2006-06-14 05:15:00   2    1.500     0.150
06092600          1   7.0    2006-06-20 13:45:00   2    1.500     0.150
06092600          1   7.0    2006-08-07 19:00:00   2    2.250     0.100

  SHIFTS WITH BAD SLOPES (SHIFT DIFF / GH DIFF <= -1.0)

STATION           DD  RAT    START_DT_TM           SLOPE  BETWEEN POINTS
---------------   --  ----   -------------------   -----  --------------
06137400          1   8.1    2006-07-05 17:59:00   -1.364 Points 1 and 2
06183750          2   7.1    2006-03-01 07:00:00   -1.352 Points 1 and 2
06183750          2   7.1    2006-07-12 19:25:00   -1.352 Points 1 and 2

  SHIFTS WITH QUESTIONABLE SLOPES (SHIFT DIFF / GH DIFF >1.5 OR <-0.67)

STATION           DD  RAT    START_DT_TM           SLOPE  BETWEEN POINTS
---------------   --  ----   -------------------   -----  --------------
06092600          1   7.0    2006-04-01 07:00:00   2.430  Points 1 and 2
06092600          1   7.0    2006-05-21 22:00:00   2.430  Points 1 and 2
06092600          1   7.0    2006-06-14 05:15:00   2.430  Points 1 and 2
06092600          1   7.0    2006-06-20 13:45:00   2.430  Points 1 and 2
06151500          4   2.0    2005-10-03 17:48:00   -0.880 Points 1 and 2
06166000          1   4.0    2006-03-27 06:59:00   3.389  Points 1 and 2
06166000          1   4.0    2006-06-20 15:15:00   3.389  Points 1 and 2
06166000          1   4.0    2006-08-08 14:35:00   -0.808 Points 1 and 2
06183700          1   4.3    2006-04-08 12:17:00   -0.942 Points 1 and 2
06183700          1   4.3    2006-04-11 19:35:00   1.863  Points 1 and 2
06183800          2   4.0    2005-10-31 18:40:00   2.025  Points 1 and 2
06183800          2   4.0    2006-03-29 21:46:00   2.307  Points 1 and 2
06293890          2   9.0    2006-04-04 18:15:00   3.123  Points 1 and 2
06293890          2   9.0    2006-04-17 15:30:00   3.123  Points 1 and 2
06295113          1   2.1    2005-10-19 18:45:00   -0.742 Points 1 and 2
06295113          1   2.1    2005-11-02 16:00:00   -0.724 Points 1 and 2
06295113          1   2.1    2005-12-13 17:15:00   -0.723 Points 1 and 2
12343300          3   1.0    2006-04-01 19:00:00   -0.907 Points 2 and 3

Script Language:
ksh

Original Author(s): Joe Nielsen, OSW

: Note the original author is noted on this page for the purposes of giving credit only. Please address questions/comments to OSW (GS-W OSW Scripts@usgs.gov).

Known Problems/Limitations/Need Improvements:

The questionable slopes are a rough first-cut and may need refining to better identify questionable curve slopes.

Installation: This script is part of the OSW Scripts Installation package and should be installed as part of that package. Users needing the script outside of the package should send email to GS-W OSW Scripts@usgs.gov.

NWIS 5.00 OSW Scripts package installation instructions:
http://water.usgs.gov/usgs/osw/adaps/OSW_scripts_pkg.5.00.html

Latest Version and Release Notes:

: Version 5.00: Included as part of OSW Scripts package for NWIS 5.00+
—updated for NWIS 5.00+ releases (not compatible with NWIS 4.11 or prior)

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