Upper Lehman Wetlands Restoration

This article was originally published in The Midden – Great Basin National Park: Vol. 17, No. 2 , Winter 2017.

Map of project area for the Upper Lehman Wetlands Restoration. The black line shows the road that was removed. Blue lines indicate streams.

By Tod Williams, Chief - Resources and Planning

The Upper Lehman Campground was developed in the 1960s by the U.S. Forest Service. The area of the northern campground access road was originally a wetland complex consisting of springs, seeps, wet meadows, and a braided riparian stream system. A road was graded in, covered with several feet of road base, and then paved. To redirect water from both the road and nearby campsites, ditches were constructed to drain wet areas and channel water through five culverts. A perennial tributary was placed in a 20 meter long ditch and diverted into the main steam of Lehman Creek.

The existing conditions showed that wetland functions and values were compromised. Wetland function was eliminated or degraded, native vegetation was reduced, and hydrologic function was impacted due to the diversion of natural flow patterns. Loss of hydrologic function was by far the largest impact. Wetlands and riparian habitat are extremely limited within the park, but because of their outsized ecological footprint, are typically valued more than other ecological systems.

Recontouring streambanks after culvert removal

NPS Photo

The campground was reconstructed in 2015. Resource staff worked with the design team to eliminate the need for the northern access road. Thus the opportunity to restore the wetland complex began. A proposal was submitted to Round 15 of the Southern Nevada Public Lands Management Act as a Conservation Initiative and funded for a four-year period. The primary deliverables for the project included:

-Restore one-half mile of riparian stream habitat to proper functioning condition
-Restore eight acres of wetland habitat to proper functioning condition
-Decommission one-third mile of road and restore native ecosystems
-Monitor biological communities to document restoration success.

All wetland and riparian types showed evidence of adverse impacts due to channelization and loss of water. There are seven mapped ecological systems within the project area. Five of these will benefit from the project:

Road prior to road base removal

NPS Photo

• Wetland Type PUBFh is a palustrine system dominated by shrubs, grasses, sedges, and emergents with an unconsolidated bottom. It is a semi-permanently flooded system with surface water persisting throughout the growing season in most years. When surface water is absent, the water table is usually at or very near the land’s surface.

• Wetland Type PSSB is a palustrine system dominated by woody vegetation, (aspen, Wood’s rose, and water birch) that are small or stunted because of environmental conditions.

• Wetland Type PABFh is a palustrine system but is dominated by sedges and emergents that grow principally on or below the surface of the water for most of the growing season. It is semi-permanently flooded system with surface water persisting throughout the growing season.

• Riparian Aspen is dominated by quaking aspen with greater than 60% cover in unconsolidated sediments near permanent water. White fir may be present in the over story but the understory is dominated by wetland grasses, sedges, and forbs.

Re-contouring and base removal

NPS Photo

• Riparian Ponderosa is dominated by ponderosa pine with greater than 25% cover in unconsolidated sediments near permanent water. White fir and aspen may be present. This type is rare within the Snake Range due to heavy selective logging at the turn of the century and fire suppression resulting in low recruitment.

Wildlife: The species below depend upon wetlands and riparian stream habitat, are species of management concern, and were documented within the project area. All of the species would benefit from larger and proper functioning wetland and riparian habitats.

• Water shrew (Sorex palustris)
• Inyo shrew (Sorex tennellus)
• Ermine (Mustela erminea)
• Long-tailed weasel (Mustela frenata)
• Yellow-bellied marmot (Marmota flaviventris)
• MacGillivray’s warbler (Oporornis tolmiei)
• Yellow warbler (Dendroica petechia)

Return of hydrologic function

NPS Photo

Park resource and maintenance staffs have completed the second year of the four-year project. To date, all asphalt and road base have been removed; the site has been re-contoured; five culverts have been removed; ditches have been filled; all springs, seeps, and tributaries have been returned to their natural channels; pools were created within the three palustrine ecosystem types; 250 ponderosa pine seedlings were planted; and seed mixes were developed for each ecosystem with the initial planting occurring this fall. Additional re-vegetation efforts and invasive species control will be required during the next two years. Post-treatment biologic monitoring will continue in all areas. Of most interest, at least to the author, was watching the re-establishment of the hydrologic function. Upon removal of the asphalt, road base, and ripping out the old roadbed, water poured out of the hillside saturating the former wetlands. Springs and seeps surfaced in numerous areas along the length of the old road, reclaiming land after a fifty-year absence.