Ownership of Submerged Bottomlands: Is Your Neighbor’s Dock on Your Property?

Throughout the summer months, we frequently get questions on the topic of water law—also known as “riparian” law. Occasionally, these questions involve waterfront property owners who are involved in disagreements with their neighbors over the location of docks or the placement of boats and boat hoists. This article is intended to provide an overview of the legal rights of waterfront property owners regarding the submerged bottomlands adjacent to their property.

A person who owns real property that abuts (i.e., borders) a natural body of water is known as a “riparian” owner. As a general rule, riparian owners own the submerged lands or “bottomlands” adjacent to their property.[1] This underwater ownership extends to the middle of the body of water. In other words, the individual who owns the shoreline, owns to the center of the stream or inland lake.

Among other rights, a riparian owner has the exclusive right to install a dock and permanently anchor boats and rafts on his or her riparian bottomlands. Similar to unauthorized entry onto your neighbor’s yard, encroaching onto your neighbor’s bottomlands is also considered a trespass.

These concepts of riparian law are a fairly well known among waterfront property owners. What is less well known, however, is how the boundaries of bottomland ownership are apportioned among riparian owners. How do your property lines extend into the lake? Where they start, where do they stop, and what path do they take along the way? These are important questions that often form the center of disputes between lakefront owners.[2]

Though survey are readily available for property owners to identify their upland property boundaries, very few lakes have been the subject of a submerged land survey. Moreover, there have only been a few cases where a circuit court judge has actually ratified the riparian bottomlands survey, a requirement to officially establish riparian boundaries.

So, if underwater surveys are not available, how do you locate your underwater property line? Well, for starters, the answer is NOT the one most people tend to think. Your submerged property line is not merely a direct extension of your upland property line into the water. The shoreline boundary is important, but the angle of your upland property line makes no difference once you get to the water’s edge.

Because your underwater property line is not merely a direct extension of your upland property line, locating your bottomlands boundary is not necessarily an intuitive task. And in some cases, it can be a pretty difficult undertaking. Under Michigan law, there are two primary methods for apportioning bottomland ownership among riparian owners.

Method No. 1: The Pie Approach.

The first method is very simple. But unfortunately, it only applies to round lakes. Where a lake is a perfect or near-perfect circle, the underwater property lines are deemed to go to the center of the lake, which results in a pie-shaped wedge for each riparian owner. Note, that were a particular lake has one or more islands that have riparian owners, there will be two centers—one on each side of the island (between the island and each shore).

In reality, however, most lakes are not perfectly round. Indeed, for the vast majority of lakes, a second approach is used to divide up the bottomlands.

Method No. 2: The Thread Line Approach

For noncircular or oblong lakes, submerged property lines are determined using the “thread line” method. With this approach, one or more so-called “thread lines” are drawn through the geographic middle of the lake between two endpoints. The thread line is then used to draw property lines to the shoreline.

In an inland lake like Torch Lake, for example, the first step is to draw a line long ways through the middle of the lake. Each riparian owner’s respective underwater property line is then identified by drawing a line that starts at the shoreline boundary between adjoining riparian owners and meets the thread line at a right angle. A crude illustration is included below.

The red line is the thread line. The blue lines are the individual lines that apportion each riparian owner’s respective bottomland boundary. What about the green light? As you can see, there comes a point at the ends of the lake where lines can no longer be drawn from the shoreline boundary to the thread line at a right angle. At this point, the pie approach described above is utilized to divide the bottomlands, with the end of the thread line serving as the center point. The green line shows how this works.

Unfortunately, there is no clear-cut rule that governs where or how to draw the thread line. Indeed, as the Michigan Supreme Court has explained, no fixed rule has ever been established for division of the bottomlands in inland lakes. The important thing to know is that the overriding goal is simply to secure an equal share of bottomland ownership for each riparian owner, in proportion to his or percentage share of lake frontage. Each case depends on its own peculiar circumstances and facts in order to equitably apportion riparian rights to riparian landowners. If that goal cannot be accomplished by the thread line method, some other method might be necessary.

Given this loose definition of equitable apportionment, reasonable people can come to different conclusions about where and how the thread line should be drawn to accomplish this goal. When legal disputes arise involving riparian property lines, it is often necessary to engage the services of a surveyor experienced in riparian bottomland surveys.

If your neighbor is encroaching on your riparian bottomlands, it is important to take some action to protect against adverse possession or prescriptive easement claims, which could actually result in your losing ownership to that property. To help prevent this type of situation, your best bet is to contact an attorney experienced in water law, who can advise you regarding your specific situation and provide direction about how to protect your riparian ownership.

[1] This is not true for the Great Lakes. See our former article for more information.

[2] The most common example deals with a situation where one lakefront owner decides to put his or her dock either near or actually on a neighbor’s bottomland. Similarly, disagreements also arise from permanent mooring or anchoring of boats and rafts along or near underwater property lines. Underwater boundary disputes also come up when there are valuable minerals, such as oil or gas, beneath the waterway, which almost always leads to fierce battles as to how the royalties to those minerals are should be apportioned among riparian owners.

Contact Us

  • Filling out form does not constitute a client/attorney relationship.
  • This field is for validation purposes and should be left unchanged.