Beaver Brook bisects the three acre Miriam E. Warren Wetlands Preserve, which is almost entirely wetland and wooded swamp. The property is separated from Bartlett Woodlot only by the raised embankment of the former railroad bed. This preserve is bounded by State Route 110 (Littleton Road) on the north which separates it from the sixty-five acre Lime Quarry Reservation, owned by the Conservation Commission. With protected wetlands on the west and private property on the east, the property is currently unused and inaccessible, but serves to connect the downtown area to the large Conservation Commission lands and has valuable wetland wildlife habitat.

The Robert & Arlene LaPorte Wetlands Preserve is an additional acre of wetlands.  Directly west of the Warren Preserve and covering the land between Beaver Brook and Littleton Road, it completes the protected corridor between the Lime Quarry and the Bartlett Woodlot.