International Boundaries on Unstable Ground

FIG Commission 1 - Professional Standards and Practice


Haim Srebro


Dr. Haim Srebro
Prof. Andrea Cantile
Prof. Don Grant
Dr. William (Bill) Robertson
Vincent Belgrave


This publication as a .pdf-file (100 pages - 5Mb)


“ Borders“, “demarcation lines“ or “frontiers“ are on one hand evoking negative associations like separation and segregation. But on the other hand they also serve for good being often the basement of a peaceful and life together with our neighbours. In the latter sense each borderline is also an important element of a prosperous coexistence. The legal act of establishment and recognition of borders between private properties is normally regulated in the national law based on a common understanding and on one constitution.

Defining, establishing and maintaining international boundaries is a very demanding task. The underlying legal framework is more complex. Several states with different constitutions and varying legal opinions are involved. International agreements are the base for the recognition of a border between two or more states.

This FIG Publication on International Boundaries on Unstable Ground is a supplement and extension to FIG Publication 59 on International Boundary Making, published in 2013. Both publications are edited by Haim Srebro. The authors Vincent Belgrave, Andrea Cantile, Donald Grant, William A. Robertson and Haim Srebro are all highly qualified experts and practitioners in “boundary making”. In this issue they focused on the boundaries in rivers and lakes and on the boundaries on unstable ground especially on glaciers and in conjunction with tectonic plate movements.

This publication is a fine and profound supplement to publication 59. It also covers the new challenge of precise GNSS-measurements in conjunction with international borders.

FIG thanks the authors for their valuable contribution as international experts of boundary-makers. We hope that this publication will be an informative guide for the definition of future international borders.

Rudolf Staiger
FIG President 2019–2022


My sincere thanks to Dr. Haim Srebro, Chair of Working Group 1.3 International Boundary Settlement and Demarcation for writing the International Boundaries on Unstable Ground as a supplement to the International Boundary Making to promote just, peace and inclusive societies throughout the world and achieve the United Nations Sustainable Development Goal No. 16 on Peace, Justice and Strong Institutions.

Winnie Shiu
Chair Commission 1 (2019–2022)


This FIG Publication on International Boundaries on Unstable Ground is a supplement and extension to FIG Publication 59 on International Boundary Making. Publication no. 59 mainly elaborated on the process of international boundary making, including allocation, delimitation in an agreement, demarcation, survey and documentation, and boundary maintenance. In addition, the publication elaborated on the joint professional support of the boundary making process. The practical parts mainly referred to land boundaries. The specified goal of the process being to achieve a long lasting stable agreed boundary line.
The main implementations of territorial boundary delimitation are demarcation of international boundaries and demarcation of internal boundaries in states, including administrative boundaries and boundaries delimiting land properties and rights of use. The cadastral boundaries are important for ensuring stable legal territorial matters. In order to fulfil the specific requirements of boundary making in these cases, the law requires fixed unequivocal and unambiguous defining of the boundary lines. 

The goal of stability of an international boundary is very important. It is the leading essence of the boundary line in order to enable peaceful and productive environment, including safe legal order and arrangements on both sides of the boundary. The goal of stability of international boundaries has been defined by the International Court of Justice[1]. The ICJ has confirmed principles of stability of boundaries. Yet, the main practical principles regarding this issue refer to stability of land boundaries, including respecting of boundary markers as such by the states concerned.

Part of the problems of boundary delimitations resulted from selection of insufficient or unstable features, either artificial man-made changing features like roads, or common natural geographic features that have been chosen for delimitation of boundary lines. Such are boundaries along mountain crests and water sheds, as well as on dynamic earth's physiographic features, such as rivers, glaciers, lakes, marshes, shorelines, edges of deserts, and even boundaries on dynamic land moving due to tectonic activities.

While demarcation problems along mountain crests are usually a result of vague delimitation that faces the detailed character of the real world, such as cases where a boundary line along mountain crests crosses valleys between mountains, or in cases where the high crests do not coincide with the general watershed line. Other demarcation problems depend on the dynamic character of chosen natural geographic features. Such are rivers and shorelines that change every second and along the year. The origin of many natural geographic feature based problems is an outcome of climate changes and global warming. Many others are a result of man-made activities.

The main problems due to global warming refer to boundary lines delimited with reference to water bodies: river boundaries, boundaries in lakes and marshes, boundaries along shorelines, and boundaries on glaciers. Rivers, lakes and marshes lose water and dry. Global warming causes lakes and marshes to shrink and in some cases to disappear. It causes glaciers to melt so that the under glacier base ground is exposed gradually. Since the boundary line on glaciers used to be delimited along the crests of the glaciers, the result of the melting process of the icy natural crests is that the newly exposed bare rocky mountain crests are located in different locations than the icy crests. Since the boundary line used to be delimited along the icy crests the neighboring parties have to define where should be located the new boundary.

The cases of river boundaries are much more diverse and much more widespread. More than one third of the international boundaries throughout the world are river boundaries. The impact of the drying process of rivers due to global warming is combined with the influence of the population growth all over the world and with artificial man-made works along rivers. Water supply is the most essential natural resource required for human living and therefore a large part of the global population lives along rivers. The need for water leads to development of large artificial water projects on rivers, sometimes building big dams and reservoirs, changing dramatically the natural water flow of the river downstream, and changing its natural balance and behavior. The water flow of a river may also be used for the production of energy, building hydroelectric power stations, with dams, reservoirs and other works and installations that change the natural behavior of rivers. These phenomena complicates the maintenance of boundaries in rivers, especially due to the trend used in many boundary agreements that the boundary follows continuous gradual natural changes in the river (accretion) and does not follow artificial changes in the river. The extent of man-made influence on the river flow all over the world leads to severe problems regarding boundaries in rivers everywhere. This reflects severe disadvantages of choosing natural geographic features for international boundary delimitations in the past, and especially for the common trend of using rivers as international boundaries.

Jones, in his remarkable hand book on boundary-making already recommended in 1945 (Jones, 1945) to avoid the use of natural geographic features, and especially rivers for boundary delimitation.
Unfortunately, natural geographic features, and especially rivers, were widely used by the colonial powers for boundary delimitations during the second half of the 19th century and the first half of the 20th century. Holdich, who participated in implementing this approach of the British Administration explained the advantages of this approach (Holdich, 2016), and while not ignoring disadvantages in certain cases, praised the use of rivers for delimitation in many cases by the words: "It is a God-sent feature for boundary-making". He explained the advantages of natural bound€aries over artificial boundaries a century ago: "They are readily delimitated and demarcated; they are inexpensive and immovable; they last well under conditions of climate, and they are, as a rule, plain and unmistakable." Unfortunately, the numerous cases of disputes regarding past delimitation of natural boundaries, and especially river boundaries, show big disadvantages of natural boundaries. Part of it is a result of global warming and global population growth. Fortunately, since the situation a century ago, the development of improved mapping infrastructure all over the world, and the development of high quality mapping technology and systems, including the use of satellites for real time accurate global positioning all over the world, supplies much better tools for precise boundary delimitation and demarcation.

Since FIG is a global NGO organization that integrates various kinds of professions regarding surveying, geodesy and additional close professional fields, including many practitioners from the member organizations, many people from the academic world, and people from affiliate national organizations, we have chosen in FIG Publication no. 59 an approach that combines theoretical and methodological parts and practical cases over the world. The practical cases in publication 59 referred to boundaries in the Middle East, with the outstanding Israel-Jordan boundary that fully implemented the methodological model; the Iraq-Kuwait boundary that was demarcated by the UN itself; case in Africa, including the Ethiopia-Eritrea, Cameroon-Nigeria and Sudan-South Sudan Abyei boundaries, all of which were relatively new delimited boundaries. In addition, it included old delimited boundaries between Nepal and India and China. Thus, it included both the international boundary in the lowest place on Earth (The Dead Sea) and the highest place on Earth (Mount Everest). We continue with the same approach in the current publication which is a supplement to Publication No. 59. Regarding river boundaries we bring the practical case of the Jordan River, the lowest river on Earth in its southern section, south of the Sea of Galilee, flowing to the Dead Sea from about -220m to -430m (below sea level). The Jordan River flows along the Dead Sea Rift along the tectonic border between the African Plate on the west side and the Arab Plate on the east side until it flows into the Dead Sea. The practical cases of boundaries on glaciers were chosen along the Italian-Swiss and the Italian-Austrian boundaries on the Alps in Europe. The reason for that was the special approach of the moving border that has been adopted in these cases. An example of the influence of tectonic plate movement on the demarcation of an international boundary is shown in a review of the Iraq-Kuwait boundary demarcation after 20 years.

It is worth mentioning that natural fenomena that influence the stability of international boundaries are sometimes interrelated. Movement of tectonic plates along the course of a river may directly influence its course, or indirectly because of collapses of its walls that block its flow, enforcing it to find or create a bypass. Such is the case of the Jordan River. The melting of glaciers, that influences the boundary line along crests, may also have an influence on the boundary line in a lake in the case that there is a boundary line in the lake, by causing a rise of the water level and horizontal changes in the coastlines of the lake. In the case of a river and a lake that both serve for boundary delimitation, if the lake partially dries, the river has to find or create a new channel through the dried area in order to get to the lake. This new channel is usually not identical with the old boundary line in the drying lake. Such is the situation between the Jordan River and the Dead Sea.    

Part 1, Chapters 1, 2 and 3, deals with boundaries in rivers and lakes. Chapters 1 and 2 deal with river boundaries. Chapter 1 elaborates on methodological aspects regarding river boundaries. Chapter 2 elaborates on the practical case of the international boundary between Israel and Jordan, in its river section that follows the Jordan and Yarmuk Rivers. The article describes changes in the two rivers during the last century, as a result of natural and artificial changes and analyzes the influence of these changes on the international and cadastral boundaries. Chapter 3 deals with boundaries in lakes, showing examples of the shrinking of the Aral Sea and Lake Chad, and elaborating on the example of the changes in the Dead Sea level and shores due to global warming and man-made influence.

Chapter 4 deals with the international boundaries of Italy, describing the boundaries between Italy and Switzerland and Austria on the glaciers of the Alps. It describes and analyzes the continuous gradual process of melting of the ice over the last century as a result of global warming. The original agreed delimitation of the international boundaries between the relevant states was along the crests of the mountains that used to be icy crests. The melting of the ice exposed the rocky crests that used to be beneath the ice. Since the exposed rocky crests follow different locations than the original delimitation and demarcation on the crests of the glaciers, the neighboring states face a problem: Should the boundary follow the old historic delimitation of the boundary or should it move to the newly exposed crest of the mountain. The article analyzes the process of negotiations between the concerning parties and introduces the chosen solution called the moving border.

Chapters 5 and 6 deal with the uncertainty of delimitation and demarcation of international boundaries on the long run, including land boundaries all over the world, due to dynamic plate movement. Chapter 5 looks at the geodetic and geophysical issues that earth dynamics may impose on the reliable enduring definition of international boundaries, being aware that no place on the surface of the Earth can be truly considered to be fixed in place due to pervasive tectonic motion. The practical case of the Iraq-Kuwait Boundary shows that despite an initial coordinate accuracy of 2 cm, the global positional accuracy has been degraded to meters during only 20 years. Chapter 6 reviews surveying standards and datums used to support international boundary positioning and documentation. Poor boundary delimitations, including poor maps, may contribute in the future to instability of the boundary and to boundary conflicts. The article elaborates on the pervasive use of satellite positioning during the last decades for international boundary delimitations. It refers to the problem to maintain on the long run permanent stability of international boundary monuments and coordinates, arguing that local reference systems may not be adequate for maintaining the stability of international boundaries. The author suggests that the delimitation, demarcation and maintenance of international boundaries would be future proofed by being connected to a regional densification of ITRF. In addition, for future consistency, the ellipsoid for calculations, the datum and the coordinates for calculations, as well as the long term adjustment to the ITRF could be a standard requirement in the technical specifications of all international boundary agreements.  

The publication has been prepared by senior practical professionals, with expertise in boundary delimitation, demarcation and documentation. Three of them served as Director Generals of national surveying and mapping organizations (Dr. Haim Srebro in Israel and Dr. William Robertson and Prof. Donald Grant in New Zealand), one served as a chief geographer in a national organization (Dr. Andrea  Cantile in Italy), and one (Vincent Belgrave) was a chief surveyor in a few UN missions regarding boundary settlement. All of the authors have long practice in international boundary settlement and demarcation. 

This FIG Publication has been prepared under the framework of the FIG Commission 1: Professional Standards and Practice work plan for 2018-2022 (Commission Chair: Winnie Shiou. Chair of WG 1.3 on International Boundary Settlement and Demarcation: Dr. Haim Srebro). Special thanks to the honorable Prof. Moshe Brawer for peer reviewing the entire publication and adding useful remarks. The publication is intended to promote the sharing of methodological knowledge and experience regarding delimitation of international boundaries and to promote Peace throughout the world.

Haim Srebro, Editor
Chair, FIG Commission 1 Working Group on International Boundary Settlement and Demarcation
September 2020


[1] Case concerning The Temple of Prea Vihear [Merits], 1962 ICJ Reports 6.

 Read the full FIG Publication 76 in pdf

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International Federation of Surveyors (FIG)
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Published in English
Copenhagen, Denmark
ISSN 1018-6530 (printed)
ISSN 2311-8423 (pdf)
ISBN 978-87-92853-22-6 (printed)
ISBN 978-87-92853-30-1 (pdf)

Published by
International Federation of Surveyors (FIG)
Layout: Lagarto


International Boundaries on Unstable Ground
Ed. Haim Srebro
Published in English
Published by The International Federation of Surveyors (FIG), December 2020, Copenhagen, Denmark
ISSN 1018-6530 (printed)
ISSN 2311-8423 (pdf)
ISBN 978-87-92853-22-6 (printed)
ISBN 978-87-92853-30-1 (pdf)