An emergency inspection of all 54 dams on Hawaii’s island of Kauai found conditions at every dam that could lead to failure, the Corps of Engineers said.
The Corps helped the state inspect the dams following the March 14 failure of the century-old Kaloko Reservoir Dam, which killed seven people.
While inspection teams found no dams in immediate danger of collapse, they discovered at least one of the following detrimental conditions at every dam: vegetative growth; reduced spillway capacity; spillways without erosion protection; no spillways; seepage not monitored or documented; overly steep embankment slopes; outlet works in need of repair; outlet works improperly abandoned; location of outlet works unknown by owner; unlined outlet tunnels; and erosion.
Additionally, many of the dams lacked basic monitoring and maintenance programs, possibly for an extended period.
A report of the inspection, a joint effort of the Corps and Hawaii’s Department of Land and Natural Resources, was posted May 19 on the department’s Internet site, www.hawaii.gov/dlnr. The Corps, which provided operations and technical expertise, submitted the report to DLNR Director Peter Young March 31. Inspection forms with detailed finding and recommendations for all 54 dams were attached.
Report recommends follow-up engineering inspections
Inspections involved only an examination of visible features of the dams. Typically, they did not include areas downstream of spillways nor investigations of upstream hydrologic conditions. Additionally, the Corps said, inspections did not include reviews of design, construction, operation, or maintenance documentation.
The report recommends all the dams be inspected by professional engineering services with expertise in dam design, construction, operation, inspection, and evaluation. It recommends operation plans and emergency action plans be prepared or updated, and a training program be implemented for dam owners and operators.
Additionally, the report recommends a program for periodic inspection of dams and installation, as warranted, of survey monuments and instrumentation for monitoring movements and water levels within dams.
Twenty-four dams on the island are classified high hazard, eight significant hazard, and 15 low hazard. Seven of the dams are classified as undetermined hazard. The report noted many of the dams are between 80 and 100 years old, and therefore not designed and constructed to current safety standards.