The Riparian Boundary That Moved
A client owns a parcel bounded on the south by a non-navigable stream. The deed, written in 1958, calls for the south line to run 'to the thread of the creek; thence down the thread of said creek' for 600 feet, then north. Since 1958 the creek has gradually shifted south by about 25 feet through slow accretion, and in 2019 a flood event cut a new channel across the client's neighbor's land, abandoning the old channel. The neighbor now claims the abandoned channel bed and asserts the boundary no longer follows the creek. The client's deed does not mention accretion, avulsion, or the abandoned channel. Title records show the client has paid taxes on the parcel as assessed, and no boundary line agreement exists.
1. Distinguish accretion from avulsion and explain how each affects the boundary along the creek.
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Accretion is the gradual, imperceptible addition of land by the action of water-slow deposition that a person could not observe from day to day. Under the common-law doctrine of accretion, the boundary of riparian land follows the water as it gradually moves, so the riparian owner gains the accreted land and loses land by gradual erosion. The boundary remains ambulatory and tracks the thread of the stream.
Avulsion is a sudden, perceptible change-a flood that cuts a new channel or abruptly shifts the watercourse. Under the avulsion rule, the boundary does not move with the sudden change; it remains where the watercourse was immediately before the avulsion. The owner does not gain the abandoned bed by avulsion, and the owner whose land is suddenly taken by the new channel does not lose title to it.
Applying this: the 25-foot gradual southward shift since 1958 is accretion, so the client's south boundary moved south with the thread of the creek over time, and the client owns that accreted strip. The 2019 flood that cut a new channel is avulsion, so the boundary is fixed at the pre-2019 thread of the old channel; the client does not automatically gain the new channel bed, and the neighbor's claim to the abandoned bed fails to the extent it rests on avulsion.
2. The neighbor claims the abandoned channel bed. Evaluate the competing claims and state the boundary you would monument and plat.
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The neighbor's claim rests on the theory that when the creek abandoned its channel, the boundary ceased to follow the creek and the bed reverted to the upland owner. That is contrary to the avulsion rule: a sudden channel change does not move the boundary, and the abandoned bed remains with the owner who held to the thread before the avulsion-here, the client, whose deed calls to the thread of the creek and who had acquired the accreted strip by gradual shift.
The client's strongest evidence is the deed call to the thread of the creek, the long history of gradual accretion, and the tax assessment history (weak but corroborative). The absence of a boundary line agreement is not fatal; the common-law doctrines supply the rule.
Boundary to monument and plat:
- The south boundary follows the pre-2019 thread of the old channel, as re-established from historical imagery, prior surveys, and the physical evidence of the old channel banks.
- The accreted strip south of the 1958 line and north of the pre-2019 thread is included in the client's parcel.
- The new 2019 channel is shown as a physical feature, not as the boundary.
Because the neighbor disputes title, the surveyor should plat the boundary based on the avulsion rule, disclose the dispute, and recommend that the parties obtain a judicial determination or a boundary line agreement if they wish to settle it conclusively. The surveyor does not adjudicate title.