watervulnerability

Ouachita National Forest Watershed Vulnerability Assessment, Southern Region (R8)
FOREST CONTEXT
The Ouachita National Forest covers over 1.7 million acres in western Arkansas and eastern Oklahoma,
and is located within the Southern Region (R8) of the USFS. The forest is primarily composed of
shortleaf pine and hardwoods and is largely within the Ouachita Mountain Ecoregion with some
ownership in the Arkansas Valley and Mid Coastal Plains - Western Ecoregion. The Ouachita Mountains
form the backbone of the forest with an east-west orientation. Weather patterns for the Ouachita
Mountains in Arkansas and Oklahoma are characterized by a temperate climate due to its location in the
center of the North American continent. Air masses that move across the national forest generally
originate from the Eastern Pacific Ocean, Western United States, the Gulf of Mexico, and Canada. The
sources of moisture for the region are the Pacific Ocean and the Gulf of Mexico. Because of the general
circulation characteristics of the atmosphere, weather systems generally move from west to east across the
Ouachita Mountains (USDA Forest Service, 1999). Mean annual precipitation ranges from 39.4 inches
per year (Fort Smith, AR) in the northwestern area of the forest to 55.5 inches per year (Hot Springs, AR)
in the southeastern areas of the forest. Corresponding surface runoff values range from 14 to 22 inches per
year.
PARTNERS
The forest was fortunate in that a subwatershed
analysis was recently completed with the Travel
Management Project. In addition, the climate
change study included consultations with Bill
Elliot (Rocky Mountain Research Station), Dan
Marion (Southern Research Station), and Steve
McNulty (Southern Research Station). Data for
climate scenarios was taken from the TNC
Climate Wizard website
(http://www.climatewizard.org/).
227 Assessing the Vulnerability of Watersheds to Climate Change