There’s a very basic proposition behind Hawaii’s efforts to crack down on barriers that hold off erosion of waterfront property: The structures protect land, but lead to shrinking beaches.

These hardened structures may include seawalls, piles of boulders or giant sandbags, often wrapped in heavy plastic tarps that can wash into the sea. They encroach on Hawaii’s public shoreline, blocking users from the beach and interfering with naturally occurring habitats.

Hawaii and Honolulu County have had mixed results in pushing back against illegal use of these beach barriers. Too often, landowners given emergency authorization to install barriers fail to remove them as required; others flout the law completely.

To further discourage their use, legislation has been introduced to require residential property owners to disclose these “erosion control structures,” whether permitted or unpermitted, on their recorded property or on public, state-owned land adjacent to the property, in real estate transactions. It’s a good idea.

The legislation also would require disclosure of any fines or enforcement actions that could be pending, whether because a permitted structure was not removed or because a structure was placed illegally.

If the structure was created with a permit from the state Department of Land and Natural Resources (DLNR), the permit’s expiration date would need to be listed. If there are unpermitted structures, fines and violation notices must be revealed.

In creating a sale offering, property owners also would need to include annual coastal erosion rates for their lots, if those are officially available.

Senate Bill 1389 and its companion, House Bill 1091, both advanced through committees in their respective legislative bodies on Thursday.

The requirement that landowners report structures erected on state land arises from the fact that by Hawaii law, all shoreline up to the highest wash of waves at any time of year is considered state-owned, and open to the public. And global warming, with its resulting changed weather patterns and rising ocean levels, is causing the shoreline to move inland along significant stretches of Hawaii’s coastline.

The state and counties want landowners to understand that while this environmental change may threaten land values, along with the size of their privately owned lot, it does not justify illegal shoreline-hardening.

DLNR’s Office of Conservation and Coastal Resources Administrator Michael Cain said state officials investigating shoreline structures have been told that the owners didn’t know there were massive sandbags on the public beach fronting their property when they purchased it.

“It would help our enforcement if we could say, ‘No, this was disclosed,’” Cain said. “And we believe it would limit landowners from building (the barriers) without authorization on state property and then selling the property before we can bring an enforcement case to our board.”

In support of the legislation, DLNR also stated that the measure will spur property owners to remove illegal barriers, rather than violate the law by failing to disclose them before selling.

This legislation hits the right notes: to help ensure that owners themselves are fully informed about coastal structures affecting their properties before selling, and to spur removal of illegal beach barriers. It also protects potential buyers from unwittingly purchasing a shrinking property, or a home with illegal structures attached. It would benefit the public by reducing damage to beaches and improving public access.