Arbor Lake Park is considered a Natural Resource Area that covers 81.4 acres.  The Grinnell Area Recreational Trail (GART) runs along the East shores of Arbor Lake.  A shelter house with restrooms sits on top of the hill on the East side of the lake. 

The 30 foot by 60 foot shelter house can be rented at the following rates:
$20.00 four hour minimum
$5.00 for each additional hour up to a $60.00 per day maximum