Arlington County schools Superintendent Patrick K. Murphy. (Arlington County schools)

Several dozen parents and civic-association representatives attended the meeting at Kenmore Middle School.

Officials hope to add 7,000 seats over the next 10 years to keep up with growing enrollment in Arlington schools, many of which are already bursting at the seams.

Staff have considered and evaluated a dizzying 60 options for new schools and additions at 18 sites. Each option was assigned a rating according to how many seats it would add versus its impact on open space and other criteria.

Those ratings helped officials winnow the number of options now under consideration to 39. [Officials said that list will be posted online soon.] In coming weeks, school staff will analyze the cost of those remaining options, as well as their impact on the need for boundary changes.

Then, in mid- to late March, they will suggest four to six comprehensive sets of changes. The public will have a chance to weigh in on those suggested sets before the school board votes on the final 10-year plan in May.

Kindergartners at Tuckahoe Elementary — one of Arlington’s most crowded schools — play in mist from a fire truck hose. (Gerald Martineau/THE WASHINGTON POST)

Reed currently houses several county programs, which would be transferred elsewhere if the school addition moves forward, and Westover Library, which would remain unchanged, officials said Wednesday.

The Lubber Run site is just a stone’s throw from existing Barrett Elementary. School officials said Wednesday that could create opportunities for a pre-k through 8th grade campus, or neighboring lower- and upper-elementary schools.

The school board wants to avoid creating mega-schools — elementary schools larger than 800 students, for example, and middle schools larger than 1,300 kids.

About 21,500 students currently attend Arlington schools, a number that’s projected to grow to about 30,000 by 2021.

The most immediate need for relief is at the elementary school level, where officials aim to add 3,000 seats. They also hope to add 2,500 middle-school seats and 1,500 high-school seats.