I have had a little experience with this issue (both as a lawyer and as a
former SSA Director) and would be happy to help. There are many glider
operations that run on parallel turf or gravel strips next to paved
runways. Examples of big operations doing so include GBSC at Sterling
Massachusetts, and all of the several glider operations at Boulder
Colorado. Many operations land on the grass "islands" between the taxiway
and runways.

The "trick" here is to NOT designate or claim the turf or grass strip as a
separate runway from the paved portion - if you do that you run afoul of
an obscure FAA airport dimensional requirement that mandates minimum
spacing between "parallel runways" (500' as I recall). Rather, you
position should be that it's all the same runway - except that one side of
it is not paved. That is the approach that the FAA Airports people have
used when these operations have been questioned. There is no FAR that
requires a pilot to "use" a paved runway - simply because on is there. The
issue is simply one of airport dimensions.

Sadly - this may be more a "local airport political" issue - but let me
know if I can help.

Good luck

Roy A. Bourgeois, President
Greater Boston Soaring Club