1888, Water District 6 Map

There may have been two very small marshy "lakes" in 1888, when this map was made:

• Pancost Lake under the "2" in section 26
• Sombrero Marsh, above the "3" in section 35.

2009, City of Boulder Open Space Map

This map has color coded our new lakes by quarter-century, based on their construction dates and when they first showed up in aerial surveys.