| Acc. No. | Year | Location | County | Observers |
| N-23-45 | 1974 |
Union Reservoir
| Weld | Bruce Webb, Jack Reddall, Jeanne Conry, Bob Andrews, Steve Larson, Harold Holt, Narca DeWoskin |
| 23-76-48 | 1976 |
Jumbo Reservoir State Wildlife Area
| Logan | Jack Reddall |
| 23-77-5 | 1976 |
Union Reservoir
| Weld | Craig Williams |
| 23-76-62 | 1976 |
Union Reservoir
| Weld | Peter Moulton, Jack Reddall, Bob Andrews |
| 23-77-60 | 1976 |
Union Reservoir
| Weld | Peter Moulton |
| 23-80-68 | 1980 |
Barr Lake State Park
| Adams | Bob Andrews, Peter Moulton |
| 23-96-23 | 1988 |
Union Reservoir
| Weld | Dave Leatherman |
| 23-88-32 | 1988 |
Cherry Creek State Park
| Arapahoe | Peter Gent |
| 23-89-18 | 1989 |
Lake Cheraw
| Otero | David Silverman, Mark Janos, Thomas Kent |
| 23-89-19 | 1989 |
Cherry Creek State Park
| Arapahoe | Bob Righter |
| 23-93-94 | 1993 |
South Platte Greenway Gravel Pits (south section)
| Adams | Karleen Schofield |
| 23-94-31 | 1994 |
Union Reservoir
| Weld | Mark Nikas |
| 23-95-38 | 1995 |
Clifton
| Mesa | Rich Levad |
| 23-95-39 | 1995 |
Union Reservoir
| Weld | Joe Mammoser |
| 23-96-22 | 1996 |
Walden Reservoir
| Jackson | Paul Lehman, Shawneen Finnegan |
| 1997-036 | 1997 |
Lake Holbrook
| Otero | Mark Janos |
| 1998-057 | 1998 |
Prewitt Reservoir State Wildlife Area
| Washington | Ric Olson |
| 1999-054 | 1998 |
Barr Lake State Park
| Adams | Tony Leukering |
| 1999-053 | 1999 |
Union Reservoir
| Weld | Steve Dinsmore |
| 1999-055 | 1999 |
Pueblo Reservoir area
| Pueblo | Tony Leukering, Peter Gent, Doug Faulkner |
| 2000-049 | 2000 |
Big Johnson Reservoir
| El Paso | Jeff Jones, Larry Semo, Mark Janos, Tony Leukering |
| 2002-215 | 2002 |
Standley Lake
| Jefferson | Doug Faulkner |
| 2002-080 | 2002 |
Cherry Creek State Park
| Arapahoe | Ric Olson, Roger Linfield |
| 2004-068 | 2004 |
Parker Regional Park
| Douglas | Glenn Walbek, Tony Leukering, Urling & Hugh Kingery |
| 2004-131 | 2004 |
Pueblo Reservoir area
| Pueblo | Bill Schmoker |
| 2005-091 | 2005 |
Pueblo Reservoir area
| Pueblo | Brandon Percival |
| 2006-124 | 2006 |
Lake Meredith
| Crowley | Glenn Walbek |
| 2010-095 | 2010 |
Chatfield State Park
| Jefferson & Douglas | Bill Maynard, Glenn Walbek |
| 2011-174 | 2011 |
Union Reservoir
| Weld | Steve Mlodinow, Thomas Hall |
| 2012-126 | 2012 |
Jackson Reservoir
| Morgan | Glenn Walbek |
| 2012-200 | 2012 |
Windsor
| Weld | Nicholas Komar, Sean Walters |
| 2013-109 | 2013 |
Lake Meredith
| Crowley | Cheryl Teuton, Michael O'brien |
| 2013-220 | 2013 |
Pueblo Reservoir area
| Pueblo | Brandon Percival, Bill Maynard |
| 2013-243 | 2013 |
Terry Lake and Clark Reservoir
| Boulder | Steven Mlodinow, Peter Gent, Nicholas Komar |
| 2014-120 | 2014 |
Cherry Creek State Park
| Arapahoe | Alec Hopping |
| 2015-110 | 2015 |
Horseshoe Lake
| Larimer | Nicholas Komar |
| 2016-066 | 2016 |
Chatfield State Park (Douglas Portion)
| Douglas | Joey Kellner |
| 2016-080 | 2016 |
North Sterling State Park
| Logan | Steven Mlodinow |
| 2017-048 | 2017 |
Queens Reservoirs (Neeskah Reservoir area)
| Kiowa | Steven Mlodinow |
| 2020-034 | 2020 |
Chatfield State Park
| Jefferson | Ric Olson |
| 2024-040 | 2024 |
Pueblo Reservoir
| Pueblo | Brandon Percival, Alan Ketcham |