WORLD METEOROLOGICAL ORGANIZATION

HOMS COMPONENT
Explanation of the criteria for classification and numbering of components H76.3.07
(NOV 2009)
Explanation of the dates on the component's description

METHOD OF DETERMINATION OF THE RATING CURVE

1.   Purpose and objectives

Development of method and software for determination of rating curve taking into account hydraulic conditions in a river channel.

2.   Description

The manual presents a method for determination of hydraulically reasonable rating curve taking into account the shape of the river channel, resistance to motion and effective gauge height of zero flow. The method is computerised by original RATIC program. It employs the logarithmic scale in accordance with the ISO 1100-2 standard and WMO recommendations (Guide to Hydrological Practices). The method is supplemented with several ways of rating curve extrapolation. Advantages of the method:

  • Applicable in various types of river channels;
  • Hydraulically correct;
  • Measurable evaluation of uncertainty interval of discharge;
  • User-friendly software;
  • Possibility of investigating rating curve changes in time;
  • Easy switch from logarithmic to arithmetical scale;
  • Printout of curve in form of graphs or table and cross-sections. The manual includes numerous examples of rating curves determined with the use of the proposed method.

3.   Input

Stage, and discharge measurements, water surface slopes, description of conditions decisive to resistance to flow and other gauging station characteristics (metadata).

4.   Output

Rating curves for given gauging station – present and historical in form of charts, tables and graphs.

5.   Operational requirements and restrictions

  1. One person with experience in processing of hydrological data and familiarity with computers can install and run the program.
  2. As the method represents high level hydraulic and hydrological engineering, its application demands good skills and expertise. The support of senior hydrologists is recommended in the application of the method.
  3. Study of manual or 3 days of training is required.
  4. Personal computer with Windows and .NET framework.
Accuracy of discharge determined by the rating curve obtained depends on the accuracy of the stages and discharge measurements, the effective gauge heights of zero flow, control section measurements and channel stability and correct determination of the rating curve.

6.   Form of presentation

Manual of 76 pages plus computing program, both in English.

7.   Operational experience

The method has been used for determination of more than 150 rating curves in various regions of Poland in different types of river channels. Examples of the determined rating curves are presented in the enclosed manual. The method has been accepted as the basic tool in the Polish Hydrological Service and in the System of Hydrology, which is a HOMS component.

8.   Originator and technical support

Institute of Meteorology and Water Management (IMGW), Warsaw, Poland.

Relevant training in English and French either in Poland or in the requesting country can be arranged through the IMGW..

9.   Availability

Manual and computing program on CD are available free of charge from HNRC for Poland at the Institute of Meteorology and Water Management, ul. Podleśna 61, 01-673 Warszawa, Poland (tel. +48 22 56 94 326, fax +48 22 56 94 317,
e-mail: bogdan.ozga-zielinskiimgw.pl

10.  Conditions on use

Cost of reproduction (if any) and mailing.
(First entered: MARCH 2010

Last updated: MARCH 2010)
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