Residents will pay an average of $3.78 more in property taxes next year on a $70,000 home, and about 10 percent more for electricity, as a result of the $53 million 1988-89 municipal budget passed late Tuesday.

The City Council held a lengthy and emotional public hearing on the proposed power rate increase, with other sometimes heated budget discussions before and after, before adopting a budget virtually unchanged from the tentative version that took shape in preliminary discussions.

Preserved, but not unchallenged, in the final budget are proposals to raise electricity rates by 9.8 percent for all classes of customers, and to give all city employees a 1 percent pay raise in July and a one-time 2 percent bonus in December.

The council rejected a suggestion by some members to postpone adopting the budget for a week, and another proposing a one-day postponement, to give members more time to study the proposed power rate increase.

The budget and the rate increase, both of which take effect with the beginning of the new fiscal year July 1, passed with a single dissenting vote, from Councilman V. Ben Porter.

Property taxes will rise slightly to fund the debt service on $4 million of voter-approved general obligation bonds that will be sold to pay for street improvements.

Electricity rates will go up to help ease a cash-flow crunch in the city Energy Department, which faced the prospect of a $1.2 million operating deficit next year if revenue was not increased.

The department has been burdened by a large increase in the number of power customers, a reduction in the amount of relatively inexpensive federal hydroelectric power available to municipal utilities and the purchase of new generating facilities to keep up with projected future power demand.

A number of residents spoke opposing the increase, some claiming mismanagement in the department, others citing the probable negative impact on business and job growth that could result.

Several questioned the lack of information available to the public about the proposed increase, which was made public just last week after the council had been considering the budget for more than six weeks.

Still others wondered why the city's Energy Board was not consulted as the rate increase proposal was put together. Some board members were briefed on the proposal only Monday and had no time to study it or offer comments.

Council members admitted feeling pressured to approve the rate increase but finally agreed more study of the issue would not have produced a different outcome.

"The main reason for the increase is our rising power costs," Councilman Stephen D. Clark said. "Our utility is an important asset, and we need to preserve it by finding the cash to maintain it."

The overall budget figure represents a 2.8 percent increase over this year's budget of $51.5 million. The general fund, which pays for the operation of the city, will rise 2.3 percent, or some $300,000, to $13.4 million.

City officials point out that spending next year will actually decrease in real, or inflation-adjusted, terms when compared to this year. Spending in the city's non-enterprise, or non-self-sustaining, departments will actually drop 10 percent next year.

The new budget also provides for the hiring of three additional police officers.