CEN/TR 17798:2022

SLOVENSKI STANDARD
01-junij-2022
Optimalno načrtovanje hidrometričnih omrežij
Optimal design of hydrometric networks
Hydrometrisches Datenetz und Optimierung
Conception optimale des réseaux hydrométriques
Ta slovenski standard je istoveten z: CEN/TR 17798:2022
ICS:
07.060 Geologija. Meteorologija. Geology. Meteorology.
Hidrologija Hydrology
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TR 17798
TECHNICAL REPORT
RAPPORT TECHNIQUE
April 2022
TECHNISCHER BERICHT
ICS 07.060
English Version
Optimal design of hydrometric networks
Conception optimale des réseaux hydrométriques Hydrometrisches Datenetz und Optimierung

This Technical Report was approved by CEN on 27 March 2022. It has been drawn up by the Technical Committee CEN/TC 318.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 17798:2022 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Nomenclature . 6
4.1 Categories . 6
4.2 Geophysical and other restraints originating from the river basin . 6
4.3 The need for data and information . 6
4.4 Technical and economic considerations due to data capture, data processing and data
archival . 7
5 Strategic considerations . 7
5.1 The need for hydrometric data . 7
5.2 Network requirements . 8
5.3 Existing and potential users of the catchment data . 8
5.4 Water resources utilization and demand for water . 9
5.5 National and international needs . 10
5.6 Consideration of other hydrological monitoring networks . 11
6 Factors affecting hydrometric design . 11
6.1 Patterns of runoff . 11
6.2 Catchment morphology . 11
6.3 Winter conditions and snow melt . 11
6.4 Availability of surrogate gauged catchments . 12
6.5 Environmental and legislative constraints . 13
7 Technical considerations . 13
7.1 Use of temporary networks . 13
7.2 Choice of measuring technique . 14
7.2.1 General. 14
7.2.2 Open channel flow measuring techniques . 14
7.3 Permanent flow measuring structures . 15
7.3.1 General. 15
7.3.2 Accessibility . 16
7.3.3 Length and quality of established data records . 16
7.3.4 Distribution of gauging stations . 16
7.3.5 Representative basins . 16
7.3.6 Coastal floodplains and other low gradient environments . 17
8 Methods of network design . 17
8.1 User survey. 17
8.2 Prioritization . 17
8.3 Physiographic impacts . 18
8.4 The use of deterministic models to inform hydrometric network design . 18
8.5 Statistical techniques . 19
8.6 Optimization and review . 20
9 Addressing uncertainty in network design . 21
9.1 The concept of uncertainty . 21
9.2 Uncertainty inherent in hydrometric networks . 21
10 The socio-economic importance of the network . 22
10.1 Techniques to justify a hydrometric network – use of cost benefit analyses . 22
10.2 Techniques to justify a hydrometric network – evaluating the strategic value of a
network . 22
10.2.1 Data requirements . 22
10.3 Network reviews and cost benefit analysis . 24
10.4 Socio-economic costs of not having hydrometric data . 25
11 Ensuring sustainability . 26
11.1 The sustainability of the network. 26
11.2 Carbon footprint and maintaining sustainability . 26
11.3 The impact of climate change and change in land use . 26
12 Decommissioning sites in a network . 27
Annex A (informative) Typical operating costs of a hydrometric network . 28
Bibliography . 29

European foreword
This document (CEN/TR 17798:2022) has been prepared by Technical Committee CEN/TC 318
“Hydrometry”, the secretariat of which is held by BSI.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
1 Scope
This document provides guidance to assist with the planning and design of hydrometric networks, to
ensure a better understanding of the water cycle and that any data are observed and collated in an
effective and appropriate manner. This document is intended for use when:
• a new network is being planned and designed;
• the nature, value and extent of an existing network is being reviewed;
• a redundant network is being decommissioned or modified.
This is to ensure that the impacts of these changes are considered objectively, and all changes are
adequately monitored and recorded.
Even though this document covers network design principles in general it focuses mainly on river
(streamflow) monitoring networks.
This document covers all aspects that are considered pertinent to the design of hydrometric networks.
The guidance is intended to be used to inform the decision-making process employed by the network’s
owners and operators. The objective nature of the review will ensure that all influential factors, both
beneficial and otherwise, are considered. This will ensure that primary and potential alternative uses of
the network are considered. It will also ensure compliance with any extant environmental legislation.
The intended audience for this document may include:
• Government, Non-Government Organizations (NGOs), agencies and other organisations which are
responsible for designing and developing hydrometric networks that provide data to support a
public service.
• Research and academic institutions that aim to develop a better understanding of the natural and
human influences on the hydrological cycle.
• Developers of the built environment seeking to comply with environmental legislation that requires
them to monitor those parts of the natural hydrological cycle that have been, or will be, impacted by
their activities.
• Any individual seeking a better understanding of the water cycle for private and personal reasons.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
4 Nomenclature
4.1 Categories
There are three categories of terms and nomenclature:
• those relating to the geophysical and hydraulic nature of the river basin;
• those relating to the need for data and information about the flow regime in the catchment;
• those relating to the processing and provision of the data and information.
4.2 Geophysical and other restraints originating from the river basin
1) Patterns of runoff and snow melt: where rainfall and snow melt occur in the catchment, producing
variations in runoff, including the long-term trends
2) Winter conditions: where permanent or semi-permanent snow fields exist in mountainous and polar
regions
3) Patterns of evapotranspiration: where rainfall totals are low and where effective rainfall can be
negligible due to high losses through evapotranspiration
4) Catchment morphology: the river pattern and nature of the catchment and its effect on average and
extreme values of discharge, stage (or river level), plant growth, temperature, water salinity and
turbidity
5) Accessibility of the catchment: particularly in remote areas and wilderness where road and transport
routes have not been developed
6) Environmental constraints: limitations on access due to environmental restrictions such as working
near or in SSSIs (Sites of Special Scientific Interest), Ramsar sites, World Heritage Sites, or more
generally at or near sites where protected fauna and flora are found
7) Legislative constraints: limitations on working due to temporary or permanent rulings, Acts,
...