When recent heavy rainfall in New Mexico filled a reservoir then spilled over a dam, compromising the structure and flooding homes and farmland near Las Cruces, a somewhat common problem was highlighted by a spokesperson with the Doña Ana County Flood Commission:
“The concern with this dam is that we aren’t sure who owns it, and therefore who would be responsible for the damage that was caused … To the best that we can estimate, that dam was built in the 1930s. It is partially on BLM land and partially on private land. We are currently investigating exactly who owns it and who will make the repairs to it.”
This is a problem in every state. Throughout the country there are hundreds, perhaps thousands, of mystery dams. If state dam safety regulators even know they exist, they often do not know much about when and how they were built, who now owns them, and whether anyone is monitoring their condition. It takes a really hard rain, overtopping or complete failure to put one of these dams into public consciousness.
The homes below that New Mexico dam reportedly were not in an official flood zone, so homeowners saw no need for flood insurance. Until the water came through the front door. (This highlights still another issue – the difference between flood zones and inundation zones. Your home may not be in the former, but could still be in the latter is there if a reservoir up the hill.)
Even when dams make it onto the state’s inventory of known dams, contact information for too many dam owners can be woefully outdated and useless. Recently DamSafetyAction mailed brochures about the need for Emergency Action Plans on all High-Hazard Potential (HHP) dams like this one. One state’s list of 1,200 dam owners (not all HHP dams), resulted in more than 200 brochures being returned as undeliverable. Some of the addresses still had rural route box numbers, which for several years now have been replaced by 911 addresses. RR mail is no longer deliverable, though it was hoped the postmaster might be able to forward. We were told that some of the dam owners on the lists are now dead. Others called to say they sold the dam long ago. Some lakes have been drained, which is cheaper and easier than rebuilding the dam to modern safety standards.
This problem of “ghost dam owners” spotlights another problem. State dam safety teams are hydrologists and engineers. Their budgets are inadequate. They typically lack support staff – even a summer intern – who could update those contact lists. When mail is returned to DamSafetyAction we try to find a more current address to pass along to the state officials. It’s often frustrating and time consuming to be Googling names and locations to see if the listed owner is still around. Trying to correct those lists might one day result in emergency planning that could save lives. But the problem with mystery dams and ghost owners is you soon hit a dead end.