Legal Question in Real Estate Law in California

If the drainage situation has caused a problem such as land subsidence, the County may be liable. However, your question suggests that it hasn't yet caused any problems and you're trying to get the situation fixed before it does. If that's the situation, you will have a tougher legal fight. If you're a neighboring property owner or otherwise potentially affected, you might sue the County to abate a nuisance.

I agree with Mr. Collins that unless you are a property owner affected by the discharge, you have no standing to do anything. I write to add that no property is ownerless. Whomever owned the property before it was subdivided into lots, leaving the dedicated pathways, still owns the pathways when the county declines the dedication. Now a days if the county did not want to accept the dedication, the county would require creation of some form of common interest association of adjacent owners to own the path, as part of the subdivision process. But of course that is now, this was then. Finding the successor owners from the 1940's may be a formidable task to the point of being impossible for all real purposes, but that's who owns it. Someone else may have a right to claim it under prescriptive rights, but until they do and get a judgment, the original subdivider is the one with standing to deal with the county.