I emailed the Foothills Park & Recreation District and here is their reply:
Thank you for your comments. Under our park rules, we do not allow any projectiles in the park. We would consider bows and arrows a projectile. We do not have staff with enforcement powers and rely on Jefferson County Sheriffs Department for their assistance.
This is from our website:
•Parks Open 5:00am - 11:00pm
•Please Leash and Clean Up After Pets
•Motorized Vehicles Prohibited
including Motorcycles, Go-Carts, Go-peds
•No Dumping or Littering
•Alcoholic Beverages Prohibited
•Glass Containers Prohibited
•Charcoal Fires in Grills Only
•Firearms and Fireworks Prohibited
•No Rockets or Remote Control Toys
•No Paintballs or Projectiles
•No Horses on irrigated Turf
•All State and Local Statutes Apply
The following rules have been officially adopted, or generally accepted for all park sites.
•No Hunting or Harassing Wildlife.
•No permanent structures will be placed or constructed on Foothills park lands without the approval of the Board of Directors. In addition, any permanent structure approved by the Board of Directors becomes the sole property of the District.
•During the winter, Foothills prohibits contact with the ice on our ponds and lakes at all our parks and golf courses.
Fishing is allowed at the following ponds and/or lakes:
(Ice fishing is prohibited)
•Harriman Lake - Harriman Lake Park
•Johnston Reservoir - Clement Park
•Hine Lake - Easton Regional Park
•Beers Sisters - Blue Heron Park Reservoir
•Wingate South Pond - Wingate South Park
All Colorado Division of Wildlife Rules and Regulations apply:
•Waders, Belly Boats, Boats are prohibited
•Contact with the water is prohibited at all parks.
•Ice Fishing - Ice fishing is prohibited on all Foothills ponds and lakes.
•Clement Park 3.2% alcohol is allowed.