• Rainbow over Half Dome


    National Park California

Hydrology, Biology, Geology Workshop


The recording of the Hydrology, Biology, Geology Workshop has been temporarily removed from yose.webex.com. We are working to increase our storage capacity and will reload the recording as soon as we have more room.

The "Giant Staircase," which includes Vernal and Nevada Falls, is one of the finest examples of stair-step morphology in the U.S.A.

The "Giant Staircase," which includes Vernal and Nevada Falls, is one of the finest examples of stair-step morphology in the U.S.A.

This workshop will focus on the biologic, hydrologic and geologic outstandingly remarkable values (ORVs) of the Merced Wild and Scenic River. Park geologist Greg Stock will provide an overview of the hydrologic,biologic,and geologic ORVs. Restoration Ecologist, Sue Beatty will present a brief management history as it affects the hydrology, geology and ecology of the Merced River. They will identify the major issues that have arisen due to past and present uses. To examine specific issues pertaining to free flow of the river the park hydrologist Jim Roche will discuss removal of large, woody debris, accelerated riverbank erosion, and the disrupted connectivity between the river and floodplain. Additionally, park botanist Lisa Acree will identify impacts and stressors to meadows including social trails, ditches and invasive species and will discuss potential management actions and ecological restoration.

Date: April 22, 2011
Time: 1-4 PM
Location: Yosemite Lodge, Garden Terrace

Agenda [623 kb PDF]
Presenter Bios. [78 kb PDF]
Comment Form [99 kb PDF]

Presentations given at the workshop:

  1. Presentation 1 [2.1 MB PDF]: Introduction
  2. Presentation 2 [3.1 MB PDF]: Overview of the Merced Wild and Scenic River's Geological Hydrological and Biological Outstandingly Remarkable Values (ORVs)
  3. Presentation 3 [6.9 MB PDF]: History of Use and Management within the Merced River Corridor.
  4. Presentation 4 [3.4 MB PDF]: River Issues in Yosemite Valley: large wood management, bridges, and loss of riparian vegetation
  5. Presentation 5 [3 MB PDF]: The Meadows of Yosemite Valley: Impacts and Stressors

Did You Know?

Sierra Sweet Bay

In Wawona and downstream, the South Fork Merced River provides habitat for a rare plant, the Sierra sweet bay (Myrica hartwegii). This special status shrub is found in only five Sierra Nevada counties. In Yosemite, it occurs exclusively on sand bars and river banks along the South Fork Merced River downstream from Wawona and on Big Creek.