Robert Thompson identified sovereignty as one of the seven ‘’models’’, or what I prefer to call perspectives, in his 2007 paper on cultural models and shoreline social conflict (Coastal Management, 35).

The primary focus of this perspective from his point of view is “individual control, boundaries, exclusion and privacy”. Words like castle, dominion, security, invasion, permanent physical occupation are cited as used in literature and legal cases to characterise the relationship between property rights and individual autonomy. He notes several examples in case law in the USA of this kind of metaphorical reasoning. While the focus on indefinitely secure boundaries may be relatively unproblematic with inland properties, Thompson states that “it has been long recognised that ocean shores are not like other boundaries”.

To quote him:

On the shore, the right of the individual to exclude and the right of the entire nation not to be excluded collide at a line in the sand that is constantly shifting. Typically, tidelines are owned by the state subject to the public trust. As a result the sovereignty model is reversed for the oceanfront portion of the coastal parcel—that is, for the portion of the lot that matters most, the part that makes it worth so much more than the lot across the street. For this portion of the parcel, ownership is not held by a single sovereign owner, but instead is covered by two titles: the jus privatum and the jus publicum [as under the public trust doctrine] ( Thompson, page 215).

Problems emerge, however, in what Thompson refers to as the “public trust problem”. First, what defines the boundary; in the USA different states have different definitions of tidal boundaries; the borders are unclear and disputes can then arise. Second, how does a local let alone a visitor know what is public and what is not and thus whether one is subject to trespass or not. Third, storms and shoreline shifts can remove boundary markers or destroy protection structures with the apparent outcome being movement of public land onto private land: or put another way “as the beach fluctuates during the course of the year or migrates over the years, the seawall or revetment might end up encroaching on public property”. I have seen many examples of this on the coast of the UK.

I was delighted to find the paper by Stocker and Kennedy in a subsequent issue of Coastal Management (2009, 37, 387-404) which examined an Australian application of Thompson’s seven “cultural models”. They do not see the sovereignty model of property owners seeking to maximise control over ocean frontage as prevalent in Australia, although they note cases where it can apply. In fact, they cite one of my old papers (Australian Geographer, 2004) on where problems have arisen.

They cite three reasons why this model is not “dominant” on Australian coastlines: first we have a culture that views access and use of the coast and the sea as “commons”; two, the practical problems of boundary definition; and three, where known, boundary markers can be destroyed by storms. To this must be added the vast stretches of the continental and island coast that reside in public domain and not subject to freehold or other forms of tenure exclusion. However, there can be no doubt that the sovereignty perspective is alive and well in many areas. Over the past few years papers by Gordon, Coleman, Corkill and myself,  amongst others, have discussed many aspects of the application of sovereignty in parts of the coast indicating that social conflicts of the type outlined by Thompson are present here. They must be addressed at various levels in legislation, in coastal planning , in community discussions, and in education on the various environmental and social values and characteristics that embrace the “wicked problems” of coastal management.


Words by Prof Bruce Thom. Please respect Bruce Thom’s thoughts and reference where appropriately: (c) ACS, 2016, posted 29th August 2016, for correspondence about this blog post please email