Here's a link to the catalog for the general summer school program for the whole county (it's got elementary, middle, and high school info).
http://www.apsva.us/cms/lib2/VA01000586/Centricity/Domain/80/SS%20Catalog2012Final.pdf
The elementary summer stuff starts on page 10. The "reading camp" as they call it is for kids who received special ed reading services and are at least one grade level below average, so that may not be a good fit for you. They do also have a general program that's half math, half language arts - it's only three hours a day (extended day is an option if you need it) that can just keep up general skill level. We did that last year - it definitely maintains, but I wouldn't call it intensive enough to necessarily teach. I believe they try to group the kids according to skill, so if your child is more or less advanced they will be with peers.