By Eliza PARTIKA

The Hahamongna Watershed Park Advisory Committee met on May 27 to discuss the Audubon Society of Pasadena’s preservation and improvement project in the Arroyo Seco portion of the Hahamongna Watershed, and progress on the Devil’s Gate Reservoir Annual Maintenance Project, a three-year effort to increase flood protection for communities downstream of Devil’s Gate Dam and restore popular sections of the Arroyo Secco Watershed. 

Dar Dowel of the Pasadena Audubon Society spoke about how improvements to the water district introduced species the Society is watching, like yellow warblers. Since 2021, the Society has worked on improving the watershed to make room for new ecosystems to develop and thrive. In addition to this the Society, with the assistance of Pasadena Parks and Recreation, will remove invasive plant species from the park, to allow native plants to grow and thrive. 

This year the invasive species targeted by the Society  includes mustard, star-thistle, annual weeds, Spanish broom, giant reeds (Latin name Arundo donax) and a South American nightshade. 

They didn’t see any more giant reeds emerging this spring, and greatly cut back on the presence of the South American nightshade and Spanish broom, said Dowel,. 

“We believe we removed all [the giant reed] from the park proper,” he said.

He added,  often staff and volunteers walk to the boundaries of the park if they are notified of the presence of the particularly brutal Spanish broom plant. 

“We’ll walk miles if there is a Spanish broom somewhere,” he said. 

The Society will continue monitoring invasive species in the watershed. Removal of invasive species was completed by the Audubon Society with the help of Pasadena Parks. 

Improving the landscape has increased the biodiversity of the area. 

The Hahamongna has seen an increase in waterfowl like herons and mallards nesting on the edges of the pool, Dowel said.  “Usually, we drain in April but they take advantage and do two cycles of nesting before July. We have a short nesting season that we did not have before.”