Methods of Riparian Allocation

[N]o rule can be laid down as to every situation, since … rights must depend in every instance upon the shape of the upland, the arm of the sea, and [the parties’] relative position to each other. The aim of all rules as applied to the rights of adjoining littoral proprietors on an irregular shore is to give each, as far as may be, a fair and reasonable opportunity of access to the channel.” Conway v Driscoll 476 So.2d 1306

“It is absolutely impossible to formulate a mathematical or geometrical rule that can be applied to all situations of this nature. The angles ( direction) of side lines of lots bordering navigable waters are limited only by the number of points on a compass rose. Seldom, if ever, is the thread of a channel exactly or even approximately parallel to the shoreline of the mainland. These two conditions make the mathematical or geometrical certainty implicit in the rules recommended by the contesting parties literally impossible.” Hayes v Bowman 91 So.2d 746

“[N]o rule can be laid down as to every situation, since … rights must depend in every instance upon the shape of the upland, the arm of the sea, and their [the parties] relative position to each other. The aim of all rules as applied to the rights of adjoining littoral proprietors on an irregular shore is to give each, as far as may be, a fair and reasonable opportunity of access to the channel.” Gillilan v Knighton

Land surveyors – as the name implies – are most often concerned with the size, shape, and topography of terra firma – but surveyors are also tasked with locating and allocating riparian rights among contiguous property owners. Maybe the job title geomatics engineer or geomaticist is a better term after all. While I have seen many surveyors produce maps of riparian rights, few have understood the methodologies of the five primary methods of riparian allocations. This fundamental lack of understanding has led to neighbors spending substantial sums of money to needlessly litigate their water boundaries.

There are six common law methods of allocating riparian rights among waterfront owners: the round lake method, the long lake method, the proportionate medial line method, the colonial method, the property line extension method, and the proportionate acreage method.  Only four common methods will be covered in this article. 

The purpose of any riparian survey is to equitably subdivide the riparian rights within a lake, river, or ocean, among the contiguous property owners.[1] “Equity” is most often defined as “equitable or ratable allocation of the waterfront area[2].” This translates to the ones ability to enjoy their specific rights, including the rights of wharf-out, ingress/egress, build a dock, and most often, “direct access from their entire shoreline frontage to their equitable share of the line of navigability[3].” These rights will be discussed in subsequent articles.

  1. The Round Lake Method

The round lake method divides the lake, or portion of a lake, into pieces of a pie. The pie/round method should be used in two circumstances: first, when the surveyor encounters a (substantially) round lake and (2) when the ends of a long lake form a semi-circle. Both circumstances are graphically described in figures 1(a) and 1(b) below.

This method may be used a professional land surveyor in three steps:

first, the center of the pie is found

second, the boundaries of the waterfront properties are found by survey

third, each waterfront boundary point is connected to the center of the pie.

Each owner is entitled to a wedge-shaped parcel that is widest at the waterfront property boundary and narrows towards the center of the circle. The larger the shoreline of a property, the bigger the wedge-shaped riparian parcel is created.

Similarly, the New York code[4] describes the method as follows:

Establishment of the littoral zone for a circular body of water is accomplished in a manner which is called the Round Lake or Pie Method. In this method, a point in the center of the body of water is established and a line drawn from the property corner at the shore is extended outshore to the established point at the center of the body of water.

In Beavertail, Inc. v. United States [5] , private property owners sued the United States over title to a 22,000-acre marsh in eastern Idaho known as Grey’s Lake. One issue in the Plaintiff’s pre-trial motion on their related tort claims was whether Idaho and/or the other property owners adjoining Grey’s Lake were required parties to the lawsuit. To determine who was a required party, the court was required to choose a method to subdivide the lake. The court ruled that based on the size, shape, and topography of Grey’s Lake, the round lake method should be employed. Interestingly, the court rationalized their choice of the round lake method based on two circumstances:

first, the Defendant, the United States of America, never offered any alternative to the round lake method until their pleading in the current motion;

second, the Plaintiffs produced an ancient map of Grey’s Lake that shows it to be subdivided using the round lake method.

It is likely that the other owners bordering Grey’s Lake used the same map. So, even though they were not explicitly mentioned in the court ruling, acquiescence and estoppel played a role in the court choosing the round lake method over the long lake method.

  1. The Long Lake Method (Proportionate Thread of The Stream Method)

The long lake method creates equitably-sized polygons between the center of the water body and the boundaries of the waterfront properties. The size of the polygon is dependent on the length of each property’s water frontage as well as the length of the lake’s thread or geographic center. The long lake method is most applicable for elongated bodies of water (lakes than are longer than they are wide). Examples are below in figure 2(a), 2(b) and 2(c).

The landward boundaries of each riparian allocation are set by the corners of each property, but the surveyor may either use the medial line or the thalweg of the waterbody as the dividing line that runs through the center of the lake based on which of the two creates the more equitable division of riparian rights within the lake, river, etc.

As the name implies, the “long lake” method applies only to lakes, ponds, and similarly-shaped waterbodies. But textbooks have also used this method on rivers and streams using the method termed “Proportionate Thread of The Stream Method.”


Understanding the definitions of medial line and thalweg is key because a misapplication of the methodology will cause serious problems. A medial line is defined as “a line that is located at equal distances from opposite banks” (i.e. a line running thru the geographic center of the lake)[6]. The thalweg, or thread of the stream, is defined as “the center of the main channel thereof. If there are two prominent channels, the thread of the stream is the center of the channel used for navigation”[7]. The surveyor should research case law in his/her respective state because the state courts may favor the medial line over the thalweg or vice versa.

The following methodology, as seen in figure 3, is used to apply the long lake method:

  1. survey the waterfront property and locate their waterfront boundary points
  2. locate the thread of the lake by bathymetric survey or medial line of the lake by mathematical computation
  3. turn right angles from the centerline of the water body to the property corners to create the riparian boundary lines between center-of-lake and property corners

Even if the lake is subdivided using the long lake method, in most cases, the two ends of the lake should still be subdivided using the round lake method.

  1. the colonial method (PROPORTIONATE SHORELINE METHOD)

The colonial method is similar to both the proportionate medial line method and the long lake method, the only difference being that the colonial method measures the 90-degree angle from the waterfront property frontage instead of from the medial line[8].

To divide the lake or river, (1) locate the thread or medial line of the stream by mathematical computation or bathymetric survey, (2) survey the waterfront property and locate their waterfront boundary points, and (3) turn right angles from the property corners to the centerline of the waterbody.

  1. The Proportionate Medial Line Method

the proportionate medial line method is similar to the long lake method. But instead of turning right angles from the medial line to property corners, the proportionate medial line method creates a ratio between medial line length and waterfront frontage. For example, in the figure below, the medial line of the lake runs 4859 feet, the total length of the lake’s left side is 8574’ (adding the water frontage of all property owners on the left side of the lake), therefore each parcel will receive 0.5667 feet of medial-line for every one foot of water frontage (4859/8574 = 0.5667 or 56.67%). This is a fair and equitable method because the size of the riparian parcel each property owner receives is not based on the geometry of their property lines, the geometry of the lake, or any other factor except the proportion of medial line vs. property line.

The proportionate medial line method may also be modified to proportion between the shoreline and the line of deep water. “Deep water” is typically synonymous with a “line of navigability.” This line of navigability is not universally defined but the Land Title Institute has defined it as “a line beyond which the water is deep enough for commercial[9]”. The “deep water” line may be found in navigable lakes, oceans, bays, or any other waterbody. Since the rights of ingress/egress of marine traffic is a paramount concern in many states, including Florida, several state courts have found that the most equitable way to apportion riparian rights is to give each waterfront property an equal proportion of the “deep water,” defined as the line of navigability (i.e. channel). The rationale behind this argument is best described in Hayes v. Bowman[10].

In Hayes v. Bowman, the appellees (the Hayes and the Abbotts), purchased submerged land from the state of Florida (shown as the hatched rectangle) with plans to fill-in the submerged land to create more waterfront parcels. The appellants (Bowman, Misener, and McEvoy) that owned lot 11, block 3, brought suit to stop the filling of the land because they asserted that “appellees’ proposed fill 2300 feet easterly of said Lots A and B toward the Channel would therefore completely bi-sect the corridor over and through which they are entitled to enjoy their riparian rights and reach the Channel[11]” The appellants claimed that, since their property was a waterfront parcel, that they were entitled to “certain riparian rights” and those rights are “determined by extending their side lot lines[12].” Contrarily, the appellees claimed that “when the Channel substantially parallels the shoreline the common law riparian rights of the upland owner are to be established in an area measured by lines drawn perpendicularly from the thread of the Channel to the corners of the property of the upland owner[13].” The appellants and appellees positions, respectively, may be seen in figures 4(a) and 4(b) below. The court found neither method persuasive. Instead, it reasoned that “common law riparian rights to an unobstructed view and access to the Channel over the foreshore across the waters toward the Channel must be recognized over an area as near “as practicable” in the direction of the Channel so as to distribute equitably the submerged lands between the upland and the Channel.[14].”

In essence, the court adopted the proportionate medial line method adopted by the Bureau of Land Management and many other states. The court also left open the possibility of using other methods when it stated “this rule means that each case necessarily must turn on the factual circumstances there presented, and no geometric theorem can be formulated to govern all cases[15].”

The final takeaway from this case was that court was more interested in protecting each waterfront owner’s “direct, unobstructed view of the Channel and as well a direct, unobstructed means of ingress and egress over the foreshore and tidal waters to the Channel[16]” than it was dictating one specific method to use to allocate riparian rights among neighboring parcels.

To divide the lake, river or ocean channel according to the proportionate medial line method:

  1. locate the thread or medial line of the stream by mathematical computation or bathymetric survey
  2. survey the waterfront property and locate their waterfront boundary points
  3. create a ratio between footage-of-properties and footage-of-centerline
  4. apply the ratio to each parcel to equitably distribute the medial line frontage between riparian owners.
  1. Prolongation of Property Lines Method

The Prolongation-of-Property-Line method is by far the easiest method of apportioning riparian rights on a lake, river, ocean, or any other body of water. The surveyor simply measures the property lines that extend to the water and then projects the property lines at the same angle into the water body.

 This is the only method discussed in this section that takes no account of equity; only the angle of the property lines. Therefore, this method has been summarily rejected by courts throughout the United States.

The Florida Department of Environmental Protection[17] stated that:

“The direction of upland boundaries is largely ignored when apportioning riparian rights. The public’s mistaken belief that riparian lines are on the extension of their side upland lines is the most frequent cause of riparian disputes. Instead, the water body must be equitably apportioned…”

Dr. Gibson’s analysis of the Prolongation-of-Property-Line method has been adopted by both Florida and New York courts of law. In Muraca v. Weyerowitz[18], three waterfront property owners in a platted subdivision located in the Town of Hempstead, New York, brought an action with the Supreme Court of New York to settle a longstanding dispute as to the allocation of riparian rights fronting the three properties. The plaintiffs argued at the property lines should simply be extended into the cove. The court did not agree. Instead, the judge, citing Freeport[19], held that “court’s paramount concern is to protect a landowner’s right of direct access from their entire shoreline frontage to their equitable share of the line of navigability.”

As seen in figure 5, there is no equity involved with this method; instead, small parcels are awarded large riparian areas, large parcels receive very little access to the channel, and riparian boundary lines often overlap with one another. When some parcels are convex and some parcels concave, even more havoc is created. The Bureau of Land Management in its Case Book states that “The weight of authority is against the use of this means[20]” Many local municipalities use this method to allocate docking rights among owners (see Orange County, Florida docking regulations). But “any compliance with [a] permit merely constitutes deference and submission to the municipal authority which owns the underwater land[21]”; the land surveyor is expected to choose smarter methods than this one. The Prolongation-of-Property-Line method should be avoided at all costs.


G.I. Joe famously said, “knowing is half the battle.” That is certainly true when the land surveyor is asked to apportion riparian boundaries. Knowing and appreciating the most common methods of riparian allocation is absolutely essential because without a firm grasp of the methodology, completing the on-the-ground survey is impossible. This article is just an introduction to the subject so further study is highly recommended before attempting a riparian survey yourself.

[1] Freeport Bay Marina, Inc. v. Grover, 149 A.D.2d 660, 540 N.Y.S.2d 471, 1989 N.Y. App. Div. LEXIS 5416

[2] Muraca v. Meyerowitz, 13 Misc. 3d 348, 818 N.Y.S.2d 450, 2006 N.Y. Misc. LEXIS 1857, 2006 NY Slip Op 26279

[3] Id.

[4] 9 NYCRR § 274.5

[5] Beavertail, Inc. v. United States, 2018 U.S. Dist. LEXIS 13351

[6] Cole Water pg. 111

[7] BLM Glossary pg. 68

[8] BLM 2009 pg. 214

[9] Land Title Institute CH 09

[10] Hayes v Bowman 91 So.2d 746

[11] Id.

[12] Id.

[13] Id.

[14] Id.

[15] Id.

[16] Id.

[17] Gibson 2013

[18]   Muraca v. Meyerowitz, 13 Misc. 3d 348, 818 N.Y.S.2d 450, 2006 N.Y. Misc. LEXIS 1857, 2006 NY Slip Op 26279

[19] Freeport Bay Marina, Inc. v Grover, [149 A.D.2d 660,] 662

[20] BLM Case Book

[21] [2]   Muraca v. Meyerowitz, 13 Misc. 3d 348, 818 N.Y.S.2d 450, 2006 N.Y. Misc. LEXIS 1857, 2006 NY Slip Op 26279

This Post Has 2 Comments

  1. Thomas Clarence

    I thought it was interesting when you explained that a riparian survey is performed to help property owners around lakes, rivers, or oceans know what their rights within the water are. If I were to guess, I would imagine that there is a special kind of equipment that needs to be used when performing this kind of survey. It would be interesting to learn more about how the equipment is used to perform riparian surveys.

    1. Tony Nettleman

      Great comments, Thomas! We will create a video before the end-of-year for sure. Dr. Nettleman

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