NF ISO 9123
Hydrometry - Stage-fall-discharge relationships
ISO 9123:2017 specifies methods for determining stage-fall-discharge relationships for a stream reach where variable backwater occurs either intermittently or continuously. Two gauging stations, a base reference gauge and an auxiliary gauge are required for gauge height measurements. A number of discharge measurements are required in order to calibrate the rating to the accuracy required by this document.The preparation of rating curves is not described in detail in this document.NOTE For a more detailed description of preparing rating curves, see the methods described in ISO 1100‑2.
ISO 9123:2017 specifies methods for determining stage-fall-discharge relationships for a stream reach where variable backwater occurs either intermittently or continuously. Two gauging stations, a base reference gauge and an auxiliary gauge are required for gauge height measurements. A number of discharge measurements are required in order to calibrate the rating to the accuracy required by this document.
The preparation of rating curves is not described in detail in this document.
NOTE For a more detailed description of preparing rating curves, see the methods described in ISO 1100‑2.
-
1 Domaine d'application
-
2 Références normatives
-
3 Termes et définitions
-
4 Symboles et abréviations
-
5 Considérations générales
-
6 Méthode de la dénivelée unitaire
-
7 Méthode de la dénivelée constante
-
8 Méthode de la dénivelée variable
-
9 Courbes et barèmes de tarage
-
10 Méthode de calcul
-
11 Vérification périodique des courbes hauteur-dénivelée-débit
-
12 Extrapolations
-
13 Évaluation de l'incertitude associée à la relation hauteur-dénivelée-débit
- Annexe A Régression multiple par la méthode des moindres carrés - Représentation matricielle
- Bibliographie
The Requirements department helps you quickly locate within the normative text:
- mandatory clauses to satisfy,
- non-essential but useful clauses to know, such as permissions and recommendations.
The identification of these types of clauses is based on the document “ISO / IEC Directives, Part 2 - Principles and rules of structure and drafting of ISO documents ”as well as on a constantly enriched list of verbal forms.
With Requirements, quickly access the main part of the normative text!

- With a single click, add a new language, the Requirements or Redline+ service and add one or more additional users.
- Whether you are in the process of acquiring a standard or it is already available in your personal space, the UPSELL service is available at every stage to help you understand it and implement it within your organization.
COBAZ is the simple and effective solution to meet the normative needs related to your activity, in France and abroad.
Available by subscription, CObaz is THE modular solution to compose according to your needs today and tomorrow. Quickly discover CObaz!
Request your free, no-obligation live demo
I discover COBAZ