Property owners who control dams and reservoirs on Kaua'i are planning to remove brush and hire consultants for more detailed studies of the structures.

The actions follows emergency state and federal inspections that found flaws at every one of the 54 dams on the island.

The visual inspections by state Department of Land and Natural Resources officials and the Army Corps of Engineers raise concerns about abandoned dams that have not been maintained and could pose a hazard because they were never properly breached.

The reports found there was no "immediate threat" to the safety of any of the dams or reservoirs, but inspectors did identify eight structures that had unusable spillways or no spillways at all, including the state-owned Lower Kapahi Reservoir near Kawaihau.

A spillway is a key safety feature that allows operators to release water during heavy rainfall before water tops the crest of the dam and does structural damage. It is unclear if any of the Kaua'i structures without spillways could pose safety hazards, but inspectors did recommend "urgent" repairs to Kumano Reservoir.

The emergency inspections of Kaua'i reservoirs were prompted by the failure of the 116-year-old earthen Kaloko dam, which killed seven people when it burst on March 14.

State Attorney General Mark Bennett has said investigators and consultants for his office may excavate areas around the Kaloko dam to determine what happened to a spillway some residents recall seeing there.

Peter Young, chairman of the Board of Land and Natural Resources, said his department is asking dam owners to immediately address the recommendations in the emergency inspection reports, with a deadline for action set for November, at the start of the next rainy season.

"Thus far, all dam owners have been very cooperative," Young said in a written response to questions. "If, however, dam owners are uncooperative, formal action by the Board of Land and Natural Resources may be necessary in the form of orders, fines and/or penalties."

The state also plans to request long-term management plans for each dam by the end of December, Young wrote.

Frank E. Kiger, president of Kaua'i Coffee Co., said Alexander & Baldwin Inc. and its subsidiary Kaua'i Coffee don't know yet how much it will cost to make all of the changes urged by the state and federal inspectors.

Alexander & Baldwin and Kaua'i Coffee own 18 Kaua'i reservoirs, and share responsibility for one additional reservoir.

Those structures include three that inspectors identified as being without spillways. The state and federal reports note that Kapa Reservoir at Ele'ele, Kumano Reservoir and Manuhonuhonu Reservoir either had no spillway or that no spillway could be found.

For Kapa, the inspectors urged that a study be done to see if a spillway is needed; for Kumano, the inspectors urged that a "properly designed spillway should be built if dam is to be used."

The inspectors also instructed Kaua'i Coffee to clear the spillway at Ioleau Reservoir of trees, describing the condition of the spillway channel and approach at the time of the March 21 inspection as "unacceptable."

A report on Ipuolono Reservoir also ordered "urgent" repairs and maintenance of an outlet system for controlling the water level there, but acknowledged Kaua'i Coffee is "aggressively pursuing" repairs at Ipuolono. Kiger said the Ipuolono blockage had been addressed by last week.

In an e-mailed response to questions, Kiger said the state recommended studies and other work "to ensure the future safety of the dams under adverse weather and other conditions. We are working closely with DLNR staff to follow up on the reports, and have provided all information requested to date in a timely manner."

Kiger said the "suggested program of work" listed in the inspections will be prioritized and undertaken over time.

"We continue to work with DLNR to review and evaluate their visual observations and resulting recommendations," Kiger wrote. "The safety of the public is our primary concern, and we will take the necessary actions to ensure this goal."

Grove Farm Co. Inc. is responsible for six more reservoirs, and Grove Farm senior vice president Allan Smith said the company expects to pay "tens of thousands" of dollars to clear brush and trees to make it easier to inspect and monitor its reservoirs.

The reports recommended additional studies of the seepage from three of the dams, and "obviously, we will comply. We're getting organized to screen consultants," Smith said.

He said the dams are used to provide water for livestock, corn and diversified agricultural crops, flower farming, taro and agriforestry.

Inspectors ordered up "urgent corrective action" at Grove Farms' Ai'i Reservoir at Kapaia to direct spillway flows away from the base of the dam, and Smith said that work has been completed.

The inspectors also ordered up a study of the seepage at Waita Reservoir near Koloa, which is rated as a structure with a high hazard potential because it can hold up to 9,900 acre-feet of water.

The state inspections found many of the dams were overgrown with trees and brush that prevented thorough inspections to look for seepage that could signal a weakening of the structures.

Inspectors raised concerns about a number of dams that are controlled by the state.

The reports note the Upper Kapahi near Kapa'a and the Lower Kapahi have no spillway, and another report remarked that trees that have grown up in the state-owned Hanama'ulu 21 Reservoir spillway channel are "unacceptable" because they can trap debris and block the channel.

Another report cited a PVC pipe that was spraying water on the slope of state-owned Mana Reservoir near Kekaha, and demanded "urgent corrective action" to clear the spillway ditch full of accumulated sediment.

Three of the dams that have been abandoned but not breached are controlled by the state Department of Hawaiian Home Lands, Young said.

They are Upper Anahola, Field 1 Kealia and Field 2 Kealia, and Young said DHHL has taken an active role in decommissioning and removing these reservoirs, retaining a geotechnical consultant to help in that effort.

Reach Kevin Dayton at kdayton@honoluluadvertiser.com.