Delta Ponds Ludwigia control

Project Description

Delta Ponds is a site reconnected to the Willamette River with a suite of habitats conducive to waterfowl, wading birds, fish, and turtles. This is the third year of treatment of an infestation of the invasive aquatic weed, Ludwigia hexapetala. Ludwigia reduces open water, competes with native aquatic vegetation, and changes the structure of ponds and side channels substantially.

Project Map

Publicly Accessible: Yes
County: Lane County, OR
Project Size:
  • 200.0 acres

Project Sites

  • Delta Ponds (approx)

Goals and Targets

Primary Motivations:

  • Conservation Mission
    Removal of invasive Ludwigia at Delta Ponds is motivated by the mission of the City of Eugene's Natural Areas and Urban Forestry Section. In particular, two parts of the mission are applicable: 1) advance and steward interconnected systems of natural areas, trees, trails, and clean waters and 2) protect and restore ecological function and native biodiversity.

Primary Goals:

  • The goal of the City of Eugene's Invasive Ludwigia Control Project is to significantly reduce the population of this aquatic invasive to diminish its ecological impacts, promote native plant recovery, and to decrease propagule spread downstream into the Willamette River system. The following are measurable objectives that the City is targeting under this project: •Reduce cover of Ludwigia in areas of low to moderate infestation by 97% from pre-treament levels as mapped in 2013 and increase open water and frequency of native plants. •Reduce cover of Ludwigia in areas of severe infestation by 90% from 2013 pre-treatment levels and increase open water and frequency of native plants.
    Progress: Between 2014 and 2015, Ludwigia had grown and spread more than observed between the 2013 and 2014 treatment years. We believe this was due to the relatively warm winter with low rainfall--conducive to Ludwigia growth. In 2015, we successfully implemented the project to remove Ludwigia from concentration areas as described. We also tested the efficacy of using volunteers to manually remove Ludwigia.

Consistent With Plans:

  • State Wildlife Action Plan
    Freshwater aquatic habitats and wetlands are identified as statewide strategy habitats in the Oregon Conservation Strategy.

Targeted Habitats:

  • Aquatic
    • Lakes and Ponds
    • Rivers and Streams
  • Wetlands and Riparian Habitats
    • Lowland Riparian Forests and Shrublands
      • Interior Lowland and Foothill Riparian Woodland and Shrubland

Targeted Species:

No targeted species were identified for this project.

Conservation Actions

Action Status Start Year End Year
Control invasive plants Ongoing Management 2013 2015
Remove Ludwigia using manual and chemical controls


Is the success of this project's actions being monitored? Yes

Monitoring Activities
The City of Eugene has established photo points for this project. Staff also float the area to look for emergent Ludwigia multiple times per year.

Quick Facts

Owning Organization

Pacific Coast Joint Venture

Managing Organization

City of Eugene Parks and Open Space
(Local Government)

Contact Information

Shelly Miller
City of Eugene Parks and Open Space

General Information

Project #: 257117
Last Updated: November 02, 2015

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