Grasmere Lake: murky no more

Wildlife, anglers enjoy a clearer lake in Washington Park

Special to Colorado Community Media - This story was originally published in Washington Park Profile/Life on Capitol Hill, a publication of Colorado Community Media.

This spring, visitors to Washington Park can glimpse a startling sight: striped bass cruising through the clear waters of Grasmere Lake. The bass are not new to Grasmere, but water clarity is. Once murky and dominated by Canada geese, the park’s southernmost lake is being reborn as a wildlife sanctuary.

Romantically named after the stomping grounds of poet William Wordsworth in the English Lake District, Grasmere was built in 1906 as part of the park’s master plan. Grasmere’s northern neighbor, Smith Lake, originally featured a bathing beach and bathhouse, while Grasmere was always intended as an ornamental wildlife sanctuary. But over the decades, urban run-off and too many Canada geese took a toll. Until recently, the soupy brown lake water held little attraction for people or wildlife.

Now Grasmere is making a comeback —and the change seems especially evident this spring. Redwing blackbirds chirrup among the rushes and a great blue heron stalks the shallows. A fishing party of white American pelicans perform synchronized dives. Chubby muskrats, perpetually hungry, paddle around the lake, looking to dine on waterweeds and crayfish. Western painted turtles bask on a log. All sorts of ducks, from buffleheads to mergansers, drop in for a spot of foraging on their way north. And a cacophony of squawking, gurgling and cooing drifts across the water from Monkey Island, where large numbers of snowy egrets and black-crowned night herons have begun to nest.

It’s not just wildlife who are flocking to Grasmere. Local anglers are showing up with coolers and tackle boxes. They arrive in quest of the bass, bluegill and channel catfish stocked by Colorado Fish and Wildlife.

What accounts for the change? The relative quiet during the pandemic has lured more wildlife into the open, but Grasmere’s renaissance actually began in 2011. In that year, the city of Denver created a master plan to restore Washington Park, which was suffering from age and its own popularity. The improvements gathered steam six years ago, when Denver Parks and Recreation planted stands of bulrushes and cattails at several spots around Grasmere, Smith Ditch, Smith Lake and the Lily Pond, a children’s fishing hole in the park’s northeast corner.

In effect, the lakes now have a series of mini wetlands, marshy areas that filter runoff and serve as nurseries for Mother Nature. According to the Colorado Wetlands Information Center, wetlands occupy only 3% of Colorado’s landmass —but foster up to 80% of the state’s wildlife.

“Wetlands have so many benefits,” said Vicki Vargas-Madrid, a wildlife biologist with Denver Parks and Recreation. “They help with storm runoff, absorb pollutants, improve water quality and provide habitat for wildlife and plants.”

In a way, these marshy areas are like secret hideouts for vulnerable creatures. Down in the watery labyrinth of rushes, fish lay eggs, tadpoles hide and muskrats conceal the underwater entrances to their dens.

Although the new wetlands provide an outsize benefit to the lake, they aren’t doing it on their own. Aerators and a switch to environmentally-friendly fertilizers also improved water quality.

Fewer geese following the 2019 culling appear to have given Grasmere some breathing space. According to Vargas-Madrid, “the geese compete for habitat and push out other species,” limiting diversity in the park.

While Denver Parks and Recreation still grapple with problems like algae blooms and proliferating geese, Grasmere Lake has come a long way. Water quality is at its highest in years, according to the Department of Environmental Health, which tests the water annually. Anglers can now choose to eat the stripers they catch. On many mornings, bird watchers haunt the wetland areas, field guides in hand.

You can actually hear the difference, especially from Monkey Island, which now seems like the Manhattan of the bird world —noisy, busy and teeming with diversity.

Nowadays, many waterfowl seem to share the opinion of picky Mrs. Mallard in the children’s classic, “Make Way for Ducklings.”

On the hunt for an inviting nesting place with no foxes or little boys on bikes, she flew over a spot rather like Monkey Island.

“That,” observed the story’s mama duck, “looks like just the right place to hatch ducklings.”