Riparian rehabilitation along the Colorado River in Glen 

Canyon National Recreation Area, Arizona 

Kelly Burke, Lawrence Stevens, Lonnie Pilkington, Tim Stephenson, Gibney Siemion

Grand Canyon Wildlands Council and NPS Glen Canyon NRA

A presentation to the TWG, 25-26 June 2018

Kel y B r e Law ence Steve s, Lonn·e Pi ngton, 1 Stephe so , 1ibney s·e . 

on 

G and Cai yo Wi dla ds Co nc I and PS Glen Canyo A 

A presen a ion o he TWG 25-26 June 20 8 
Rehabilitation Setting in 

Glen Canyon

Reduced flood frequency and sediment transport, no recruitment of 

native tree willow Salix gooddingii; beaver herbivory.

Ecological stabilization of the riparian zone allowed colonization of lower 

riparian zone by non-native tamarisk (Tamarix spp.).

Reduced flow fluctuations since 1991 allowed increased plant cover in 

lower riparian zone. 

Tamarisk leaf beetle (Chrysomelidae: Diorhabda elongata) causing 

mortality and rapid ecosystem change; restoration of Salix gooddingii

and other native phreatophytes needed to provide corridor habitat for 

wildlife in the recreation area. 

Potential for northern leopard frog translocation to enhanced/

constructed frog habitat.
Conceptual Plan for Riparian 

Rehabilitation Projects

Accessible pilot site: Lees Ferry, assess tamarisk removal and reestablishment of native vegetation. Heavy equipment and use of Lees Ferry 

irrigation system.

Untreated site: Paria Beach tamarisk stand, long-term monitoring control 

(until alteration by tamarisk beetle).

First stage remote site: Hidden Slough, apply Lees Ferry findings, boat 

accessible every 2-3 days, nearby camping, chainsaw removal and gravity 

irrigation, emphasize Goodding’s willow recovery.

Second stage remote sites: Hidden Slough plus Leopard Frog Marsh, 

riparian revegetation and leopard frog habitat rehabilitation. Construct frog 

ponds and monitor for habitat suitability and stability.

Expanded monitoring sites: Paria Beach plus Lees Ferry, Hidden Slough, LF 

Marsh.

Share findings with other riparian rehabilitation programs - Grand Canyon. 
Rehabilitation Project Sites


Lees Ferry site after 9 yrs.
Hidden Slough-view prior to tamarisk 

cutting, fall 2008

Zion National Park 

Fire Crew Burn Photos

(March 2009)
Irrigation Piping (Sept 2009)
Seeding (four-wing saltbush, April 2009 

and February 2010) 

Site maintenance: 

boat with pump, tank refill 

pipe, cutting tamarisk 

shoots
Hidden Slough - Summer 2014
Results

Populus fremontii, Salix gooddingii and S. exigua, Acer negundo, and

Baccharis emoryi required depth to water table of <2 m. 

Beaver fencing is essential, some success with sandy paint applied prior to 

HFEs to prevent herbivory above caging. 

Mean rate of tamarisk manual removal at HS was 0.003 ha/hr (2 weeks large 

field crew). Cut stumps were treated with Garlon, retreated and in following 

years re-sprouts hand cut. 

Gravity-driven irrigation proved most effective at HS. 

Phreatophyte pole planting is more efficient at remote sites. 

Rehabilitation sites require growing season maintenance 2-3 times/week. 

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Results continued...

Lees Ferry, native vegetation cover increased to >80 percent within 3 yr, and 

riparian tree height exceeds 10 m after 10 yr. Hidden Slough plantings 

survivorship ave. 82% (2014)

Avian diversity and herpetofaunal density at Lees Ferry exceeded that in the 

pretreatment tamarisk stand and at control PB within 2 yrs.

Small mammal assemblage at Lees Ferry remains a monoculture of 

Peromyscus eremicus, lower diversity than at PB and LFM. LFM supports 

the only known population of western harvest mouse (Rheithrodontomys 

megalotis) remaining along the Colorado River below Glen Canyon Dam. 

Muskrat, raccoon, and possible badger tracks observed, and Woodhouse’s 

toad (and juveniles)

Rehabilitation of riparian vegetation can be rapid and effective, but not all 

ecosystem components recover at equal rates. Rehabilitation is farming.

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Future opportunities...

Proposed next stage: Paria Beach riparian rehabilitation.

Future remote sites: implement priority sites identified in NPS Glen Canyon 

reach. Complete a corridor of native riparian habitat.