Press Release Back Number(2007)

1. 1) Limit adjustments in computer formula: 152 sites (79 power stations)
   Computer calculations automatically adjusted the limits so that the records showed the maximum intake was drawn, even when water surface disturbance or other factors caused the maximum intake to be exceeded.
   Attached Reference 1 gives an overview of how limits are adjusted based on water level.
2. 2) Limit adjustment when records created, based on readings: 191 sites (104 power stations)
   When readings of water volumes were taken manually, the limits were adjusted so that the records showed the maximum intake was drawn, even when water surface disturbance or other factors caused the maximum intake to be exceeded.
3. 3) Limit adjustment based on water gauge settings: sluice gates at 88 sites (61 power stations)
   Water gauges are reset when the water level rises when drawing the maximum intake. However, because of such factors as channel disrepair, the formula was not revised after resetting, and the limits were adjusted so that the records showed the maximum intake was drawn, even when the maximum intake was exceeded.
   Attached Reference 2 gives an overview of how limits are adjusted based on resetting of water gauges.

Fixed values are set for maintenance flow and release in order to simplify water level management of reservoirs, etc. A revision was made such that flow could not be negative, so that water input and output would be consistent.

In some cases, water for miscellaneous uses at power stations was drawn from rivers.
Water for power station cooling and miscellaneous uses was also drawn from power generation channels, and in some cases the amount drawn was found to be in excess of the amount permitted.

(units: number of sites)

The volume of power station water intake was within the maximum permitted, but in cases where intake declined at one of the two sluice gates, the other sluice gate drew more than the maximum intake permitted for that sluice gate.

The Company did not undertake river usage application procedures under River Law Article 24 for control and communication lines, etc. which are part of the power station equipment.

[Causes of situation]

Because river water levels rise and fall naturally, a certain non-response range is established so that gates can be controlled with stability, thus allowing better control of water intake. As a result, there are control delays and errors. Although maximum intakes are not exceeded on average, excess intake does occur temporarily. The Company was performing limit adjustments in the records in these cases.

[Recurrence prevention measures]

Permanent countermeasures

Interim countermeasures

[Causes of situation]

Revisions were made to simplify management and because of technical problems in getting quantitative data

[Recurrence prevention measures]

Hereafter, the Company will consult with river administrators regarding the handling of this quantitative data.

[Causes of situation]

Only a very small amount of water was drawn from rivers for miscellaneous-use water, and the Company did not realize this action required an application under the River Law. In addition, staff members believed that water drawn from power generation channels was being used to generate power.

[Recurrence prevention measures]

The drawing of miscellaneous-use water from rivers has been discontinued by March 13.
In cases where the company has drawn cooling water and miscellaneous-use water from power generation channels in amounts exceeding the permitted limits, we are dealing with the situation by consulting with the river administrator and making immediate improvements, such as by limiting output in consideration of the ratio of the amount of these types of water drawn to the maximum intake.

[Causes of situation]

There have been other cases in the past that did not conform to water usage rules, but in those cases the Company consulted with the river administrator to make improvements, such as making sure water rights were updated and other steps taken with appropriate timing.
As a result, only one site was in need of corrective measures in this survey.

[Recurrence prevention measures]

We are consulting with the river administrator and making immediate improvements.

[Causes of situation]

There was poor understanding about making application under the River Law.

[Recurrence prevention measures]

The Company will consult with the river administrator on how things are presently handled and will take corrective measures. We will also revise our internal rules to prevent recurrence of the situation.

[Causes]

Even before this survey, the Company was making a sincere effort to correct situations like the above regarding appropriate water intake observation and record-keeping as well as matters pertinent to River Law Article 23 and other laws and regulations concerning rivers.
In some cases we had already consulted with the river administrator and solved the problem or were consulting at the time, but in other cases there was poor awareness of the situation and no action had been taken.

[Recurrence prevention measures]

In addition to the measures to prevent recurrence of the individual situations as mentioned in the previous paragraph, the company is taking the following general measures to prevent recurrence.