No more than 25% of the required common space shall be devoted singularly or collectively to detention ponds, sand filters and retention ponds, provided, this limitation
shall have no application to any retention pond that meets all of the following:

1. The retention pond or closely connected series of ponds is one-half acre water surface area at normal pool in size or greater;
2. The retention pond is surrounded by open space;
3. The retention pond is accessible to all homeowners; and
4. The retention pond is an amenity complying with Sec. 7.2.6.