At a meeting earlier this month the board approved the 90/10 split, in which the water department would pay 10 percent.
Director Bruce Kuhn made the motion calling for that split and was supported by directors Lloyd Allen and Rudy Maldonado. Mendoza and board President Andy Horne voted against that motion.
Mendoza has argued that during the summer the IID board adopted a budget in which power was to pay 76 percent of the computer costs and water 24 percent.
She has said to change the split would cause a $1.2 million hit to the power budget, which she said could force a cut in power projects for the year or lead to increased rates.
Kuhn has argued that when the board moved in the late 1990s to purchase the SAP software system, it did so with the intent of having power pay 90 percent of the costs.
He said SAP was meant to benefit the power department in light of the pending deregulated power market.
Kuhn said when the board adopted the budget during the summer and divided computer costs by 76/24, it went against the intent of the board seated in the late 1990s.
On the canal lifeline issue, the board is expected to hear a report that John Hunter, a San Diego-area man who proposed the lifeline project, has obtained insurance for it.
While the board has approved the lifelines, it did so on the condition that Hunter provide the insurance for the project.
Board members have said that once Hunter shows he has obtained the insurance and the board approves it, the board will start a study regarding how to put in the lines.
IID officials have said they would like to see the lines up by the summer.
The board will consider a request from CalEnergy to have more time to make payments to the district.
CalEnergy, a geothermal company that operates 10 plants in the Imperial Valley, has not been paid by Southern California Edison for five months.
Eight of CalEnergy's 10 plants are contracted to provide power to Edison, which owes CalEnergy $140 million.
Because it has not been paid, CalEnergy has not paid more than $1 million for power and water services owed to the district.
A local Superior Court judge ruled Thursday that CalEnergy can suspend its contract with Edison and sell its power to a utility that can pay for it.
In other action Monday, the board will consider authorizing staff to move forward with obtaining all necessary materials to provide power to the under-construction beef-processing plant in Brawley.
The district and B.P. Ventures, the company that will operate the plant, are still negotiating an agreement in which the district would provide power to the facility.
That agreement is expected to reached within 45 days.
However, according to IID staffers, they need to move immediately on the project to have power ready for the plant when it opens Oct. 1.
Staff Writer Darren Simon can be reached at 337-4082.