San Diego voters will consider a ballot measure Tuesday that would require more revenue generated by leases at Mission Bay Park to be used to maintain the recreation area.

Proposition C would change the city charter, requiring that 75 percent of lease revenues that exceed $23 million be spent on improvements to Mission Bay Park. The threshold would drop to $20 million after five years.

The remaining 25 percent generated from Proposition C would be spent on regional parks, including Chollas Lake, Balboa, Mission Trails, Otay River Valley, Presidio, San Diego River, various open spaces and beaches.

The measure would expire after 30 years.

Only about 8 percent of the revenue generated from hotels, SeaWorld and other lease holders goes to Mission Bay Park. Much of that money is now diverted to the city's general fund.

There were no arguments against Proposition C on the ballot statement, but some City Council members have expressed concern that it would remove their flexibility in municipal budgeting.

Proposition C is expected to raise $5.3 million for Mission Bay Park in 2010 and $11.7 million by 2015. Other regional parks in San Diego would get between $2.5 million and $3.9 million annually over the same period.