Shoreline Certification and Accretion on a North Shore Lot
A beachfront lot on Oahu's North Shore is for sale. The 1985 shoreline certification places the shoreline 120 ft seaward of a concrete seawall built in 1970 under a county permit. Your 2024 field survey finds the vegetation line 18 ft mauka of the 1985 certified line, a debris line 35 ft mauka, and an erosion scarp 8 ft seaward of the seawall. The owner argues that the vegetation line has moved makai and that the new land is accretion, adding 18 ft of lot depth. The buyer's attorney asks you to map the property boundary and to say whether the state or the owner owns the strip between the 1985 line and today's vegetation line. The beach is used by the public and the county has a shoreline setback ordinance.
1. Under Hawaii law, what defines the shoreline for boundary purposes, and which field indicator-vegetation line, debris line, or scarp-is generally controlling?
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Hawaii defines the shoreline as the upper reaches of the wash of the waves, other than storm and seismic waves, at high tide during the season of the year in which the highest wash of the waves occurs. It is usually evidenced by the edge of vegetation growth or the upper limit of debris left by the wash of the waves. In practice, the vegetation line is generally the more stable and controlling field indicator; the debris line can be pushed higher by storm waves or unusual conditions. The erosion scarp is evidence of recent erosion but is not itself the legal shoreline. Only the chairperson of the Board of Land and Natural Resources can certify the shoreline; a private surveyor maps evidence and prepares a certification request, not a final legal shoreline determination. The 1985 certified line is the starting comparison, but the current shoreline is an ambulatory boundary.
2. How do you distinguish accretion from erosion or avulsion here, and what is the effect of the 1970 seawall on the boundary?
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The vegetation line is 18 ft mauka of the 1985 line, which indicates landward movement-erosion-not accretion. The owner's claim that the line moved makai is contradicted by the measurements. The debris line 35 ft mauka is likely storm evidence and should not be used to claim accretion. There is no evidence of a sudden avulsive event in the record; gradual erosion moves the boundary mauka and the upland owner loses the eroded strip. The 1970 seawall complicates the analysis because a hardened structure can interrupt the natural ambulatory boundary and may affect whether new sand seaward of the wall belongs to the upland owner. The scarp 8 ft seaward of the wall suggests active erosion. I would map the vegetation line, the debris line, the scarp, and the seawall, and flag the seawall issue for legal review rather than assume accretion.
3. What would you put on the survey map and what disclaimer or note is appropriate, given that only the DLNR chair can certify the shoreline?
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Map the 1985 certified shoreline as a reference line, and map the observed 2024 vegetation line, debris line, erosion scarp, and seawall with clearly labeled symbols and distances. Show the measured 18-ft landward offset of the vegetation line and the 35-ft debris line. Do not label the vegetation line as the “certified shoreline.” Add a note that the shoreline shown is an observed field line for comparison and is not a shoreline certification; final certification rests with the chairperson of the Board of Land and Natural Resources. State the date and method of observation, the tide and weather conditions if known, and that the debris line appears storm-influenced. Recommend that the buyer obtain a current shoreline certification and legal advice on the seawall and the state's interest in the beach below the shoreline.