Purgatoire Watershed Weed Management Collaborative

Access to high-level noxious weed management for all landowners is becoming a reality in the Purgatoire Watershed.  In January of 2016, the Purgatoire Watershed Weed Management Collaborative (PWMMC) was formalized. 
The Goal of the PWWMC is to maintain, protect, and improve the ecological integrity, agricultural productivity, and the economy of the Purgatoire River Watershed through non-native noxious weed control and landscape restoration.
The economic and environmental cost of uncontrolled noxious weeds can be devastating to communities.  However, when local governments, organizations, private landowners, corporations and other entities work together the devastation can be stopped and damage reversed.
Your support of the PWMMC will ensure the long-term protection of the Purgatoire Watershed!

Creation and Function of the PWWMC

In January of 2016 three key partners entered into an MOU to move the PWWMC  forward by hiring a full-time coordinator: RiversEdge West, Spanish Peaks-Purgatoire River Conservation District (SP-PR CD), and the Purgatoire Watershed Partnership (PWP).  Currently, the coordinator is funded for three years.
The new PWWMC Coordinator, Shelly L. Simmons, is based out of the SP-PR CD office in Trinidad, CO. She can be reached at ssimmons@purgatoireconservation.org. Shelly’s focus is watershed-wide and will be centered on establishing the PWWMC as an independent, permanent, financially self-sustaining organization.
Las Animas County has been an active partner and very instrumental in the formation of the PWWMC. The County’s Noxious Weed Coordinator is Bob Lucero.  Las Animas County takes a very proactive approach to weed management, working to control noxious weeds on County right-of-ways and other high priority areas. Las Animas County and PWWMC will work in tandem, coordinating all noxious weed control efforts including mapping and treatment within the County.
Many other partners actively support the PWWMC and are making significant contributions to the effort.

Why is Protecting the Purgatoire Watershed so Important?

The Purgatoire Watershed is one of the most ecologically intact watersheds in the State of Colorado.  It boasts amazingly intact native riparian vegetation and extraordinary biological diversity, all while supporting vibrant communities and robust agricultural production.  However, several non-native invasive plant species have been encroaching into the watershed over the past fifty years.  
Invasive plants of highest concern within the watershed include woody invasive plant species, tamarisk and Russian-olive, prevalent in riparian areas (rivers and streams); African rue, which invades rangeland and more xeric (dry) waterways; Russian knapweed, which has exploded in several irrigated farming areas; Scotch, Canada and musk thistles, and hoary cress, which are especially prevalent in ditches, roadways, and highly disturbed areas.  Currently, the infestation of most of these invasive plants is manageable within the watershed.  Controlling them will cost substantially less now than in the future, and will generally not require extensive revegetation efforts.
The growing interest and continued support for management of non-native invasive plant species within the watershed and local communities have provided a timely opportunity to proactively deal with the problem within one of the most significant natural drainages in eastern Colorado, yielding the most impact dollar for dollar.

Goals and Outcomes

The Goal of the PWWMC is to maintain, protect, and improve the ecological integrity, agricultural productivity, and the economy of the Purgatoire River Watershed.  This goal will be achieved through controlling non-native invasive plant species; improving native vegetative cover and thus native wildlife habitat; increasing public awareness and support of watershed health; and ensuring long-term watershed protection by establishing the PWWMC as a permanent financially self-sustaining organization.
Desired outcomes include improvement of water resources; re-establishment of native vegetation where it has been degraded by invasive plant species; improvement of habitat for native wildlife; protection of communities from wildfire and flooding; enhancement of agricultural production; and enhancement of hunting and other recreational access and opportunities.

Active Partners

  • Private Landowners
  • Spanish Peaks-Purgatoire River Conservation District
  • Branson-Trinchera Conservation District
  • Tamarisk Coalition
  • Las Animas County
  • Purgatoire Watershed Partnership
  • Purgatoire River Water Conservancy District
  • The Nature Conservancy
  • CSU Extension, Las Animas County
  • City of Trinidad
  • Colorado State Forest Service
  • Colorado State Land Board
  • Colorado Parks and Wildlife
  • Colorado Department of Agriculture, Noxious Weed Program
  • Colorado Water Conservation Board
  • Natural Resources Conservation Service
  • US Fish and Wildlife Service Partners for Wildlife
  • Purgatoire River Anglers-Trout Unlimited Chapter 100
  • YOU!

Watershed and Noxious Weed Plans

Watershed Plan
The Purgatoire River Watershed Plan was completed in 2014 by the Purgatoire Watershed Partnership (PWP) .  PWP is taking a phased approach to implementing the plan by first focusing on goals #4 and #5 (mitigating invasive plants and riparian habitat improvement). Implementation of these watershed plan goals will also overlap with other goals, such as healthy forests and rangeland.
Woody Invasives Plan
A woody invasives management plan for the Purgatoire Watershed was completed in 2008, approved by the Colorado Department of Agriculture’s State Weed Coordinator. The plan is based on a set of guiding principles that focus on ecological, social-cultural, economic, and research considerations. The Purgatoire Woody Invasives Plan stands alone but is also a key component within the larger Arkansas River Basin Plan
Las Animas County Weed Plan
Las Animas County is very active with noxious weed control, focusing mainly on County right-of-ways.  They are also involved with a multi-organizational effort in conjunction with CSU Extension and the Colorado Department of Agriculture’s Noxious Weed Program to eradicate African rue, a List A noxious weed.  Las Animas County’s weed plan and other relevant weed information can be found here.  Partners plan to update the County weed plan in the near future.


Mapping of tamarisk and Russian-olive within the Purgatoire Watershed was completed in 2006.  The mapping was funded by the Colorado Water Conservation Board and Purgatoire River Water Conservancy District, and was conducted by the Tamarisk Coalition.  Mapping data provided TTP partners with the foundation for targeting control efforts and developing cost estimates for treatment.  More accurate project level mapping is utilized as well for specific project sites and monitoring activities. 
Las Animas County also maps locations where they have treated herbaceous weeds.  For information on herbaceous weed control efforts and locations in Las Animas County please contact Bob Lucero at Robert.lucero@lasanimascounty.org .
The PWWMC and Las Animas County will work together to coordinate County-wide noxious weed mapping and treatment efforts:
  • Prioritize and coordinate control efforts – species, locations, and treatment protocols.
  • Utilize the Ag Terra Logger Spray system and/or ArcGIS compatible tools to map known and new noxious weed infestations and map noxious weed treatment areas.
  • Create a central repository to house noxious weed data for the County and eventually the Watershed.
  • Create annual infestation and treatment maps.
Mapping data will also be shared with the Colorado Department of Agriculture’s Noxious Weed Program to ensure accurate state-wide weed inventories and documentation of new weed infestations.

Control Efforts

Approximately 1,700 acres of tamarisk and Russian-olive and other herbaceous weeds have been treated within the Watershed since 2005.  Annual monitoring and maintenance of project sites is an integral component of project implementation.  
Overview of tamarisk and Russian-olive control efforts:
  • Upper Reaches of Watershed, Trinidad Lake State Park   ~214 acres have been treated on the Park since 2006. 
  • Purgatoire Mainstem, NRCS EQIP Invasives Program  ~96 acres were treated on private lands along the Purgatoire River near the base of Trinidad Reservoir, and near the Town of Hoehne. 
  • Chacuaco drainage-largest tributary to the Purgatoire  ~891 acres on private and State lands have been treated since 2008. The Chacuaco drainage is the largest tributary to the Purgatoire River and was a priority treatment area.
  • Purgatoire Mainstem, Trinidad River Walk  ~80 acres were treated in 2010 and 2011 along the Trinidad River Walk, and approximately 69 acres in 2014.  This stretch of the Purgatoire is heavily infested with Russian-olive.  
  • Upper Purgatoire Mainstem and Tributaries  ~130 acres have been treated in the upper reaches of the Watershed above the City of Trinidad since 2010. 


Project partners have been working with the Colorado Department of Agriculture’s Insectary to establish tamarisk leaf beetles within the Watershed as part of an integrated management approach.  Tamarisk leaf beetles have been released in the Watershed since 2009.  
In 2012 the tamarisk leaf beetles began showing good establishment in the Hoehne area.  The beetles have since become widely established in Las Animas County and other areas in the Watershed, such as Higbee Valley in Otero County.  It is hoped that once populations are fully established, the leaf beetles will serve as the primary control mechanism for tamarisk within the Watershed.  
Click here for more information on tamarisk leaf beetles and maps depicting the beetle expansion within the Western US. For more information about tamarisk leaf beetles please visit http://www.tamariskcoalition.org/programs/tamarisk-beetle or https://www.colorado.gov/pacific/agconservation/tamarisk-biocontrol.


Funding is critical for project success.  The PWWMC has worked very hard to acquire grant funding for project implementation. Since 2007 approximately $300,000 has been awarded to the partnership to conduct mostly tamarisk and Russian-olive removal.  In 2015 efforts were focused on securing funding for a coordinator; efforts were successful and the coordinator position has been funded for approximately three years.
Major Sources of Funding since 2007
  • Colorado Division of Wildlife, Wetlands Grant Program
  • Colorado Water Conservation Board, Tamarisk and Russian-olive Program (TRO)
  • Colorado Water Conservation Board, Invasive Phreatophyte Control Program (IPCP)
  • Purgatoire River Water Conservancy District
  • Colorado Department of Agriculture, State Weed Fund 
  • Purgatoire River Watershed Conservancy District
  • Colorado State Land Board, Noxious Weed Fund (for SLB owned properties)
  • Colorado State Forest Service, State and Private Forestry (S&PF)
  • Gates Family Foundation

Notable Accomplishments

  • 2006 – completion of watershed mapping of tamarisk and Russian-olive
  • 2008 – completion of woody invasives strategic plan
  • 2007-2012 – completion of ~1,411 acres of treatment, consisting most of tamarisk, with the majority of treatment on private lands within the Chacuaco drainage (the larges tributary to the Purgatoire) and the upper reaches of the watershed
  • 2013-2015 – completion of ~150 acres of treatment along the Trinidad River Walk, consisting mostly of larger Russian-olive trees
  • 2016 – establishment of a formal collaborative, with the goal of creating a permanent financially self-sustaining PWWMC

PWWMC Contact

Shelly L. Simmons
Purgatoire Watershed Weed Management Coordinator
RiversEdge West/Spanish Peaks-Purgatoire River Conservation District/
Purgatoire Watershed Partnership

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