In two lawsuits, Clackamas County landowners want judges to clarify the modified Measure 37 property-rights law and force local government to pay claims.

The lawsuits are among the first in Oregon to test whether landowners beat the clock by filing for a land-use waiver, building roads, drilling wells and otherwise demonstrating that projects qualify for exemptions to continue under Measure 49, which took effect earlier this month and restricts rural development.

Land-use attorneys acknowledge that Oregon's property-rights laws are murky. Their legal interpretation, by some accounts, could determine whether the Oregon tradition of protecting farm and rural land gives way to Los Angeles-style sprawl.

Landowners have filed more than a dozen lawsuits against Clackamas County over Measure 37, but the two most recent suits are the first to target Measure 49.

"Measure 37 and Measure 49 are complex, and a lot of people are confused by them. But they affect not only individual landowners but all of us in Oregon, including our children and our children's' children," said a Clackamas County spokeswoman, Ellen Rogalin.

Under Measure 37, landowners were permitted waivers to develop property under rules that existed at the time of their purchase. Measure 49 scaled back the previous measure, banning land-use exemptions for commercial and industrial development and restricting exemptions for residential development involving more than 10 home sites.

But there's a loophole: Developments substantially under way before Measure 49 took effect have the "vested right" to continue. Experts disagree on what one must do to attain a vested status, and the lawsuits endeavor to resolve these questions.

In one of the suits, the developers of a 41-lot subdivision in the Petes Mountain area between Wilsonville and West Linn want a declaration that the project is vested and can proceed. The lawsuit also demands compensation for "inapplicable regulations" that the landowners have said devalued the property by $12.5 million.

Landowners Donald Bowerman and Leigh Campbell have spent, according to an estimate from their developer, at least $750,000 on permits, hydrology studies, erosion control, engineering, traffic reports, water and septic studies, grading work, legal fees and other efforts to develop their 60 acres, which they acquired in 1969 when few land-use restrictions were in place.

The development has infuriated some neighbors, who say that if workers build the subdivision, wells could run dry.

The other lawsuit, filed by George Hansen and Earlene Hansen, asks the court to declare that construction can continue on a 37-lot subdivision on land near Oregon City acquired in 1964 and now zoned rural agricultural and single-family residential.

Peter Zuckerman: 503-294-5919; peterzuckerman@ news.oregonian.com