The RHEM Web Tool

RHEM is designed to provide sound, science-based technology to model and predict runoff and erosion rates on rangelands and to assist in assessing rangeland conservation practice effects. RHEM is a newly conceptualized, process-based erosion prediction tool specific for rangeland application, based on fundamentals of infiltration, hydrology, plant science, hydraulics and erosion mechanics.

Long-term Agro-ecosystem Research Initiative

LTAR Walnut Gulch Experimental Watershed DAP GIS Layers

The USDA-ARS Southwest Watershed Research Center (SWRC) operates the Walnut Gulch Experimental Watershed (WGEW) in southeastern Arizona as an outdoor laboratory for studying semiarid rangeland hydrologic, ecosystem, climate, and erosion processes.

Since its establishment in 1953, the SWRC in Tucson, Arizona, has collected, processed, managed,…

Long-term Agro-ecosystem Research Initiative

LTAR - Meteorological Stations - Walnut Gulch Experimental Watershed

The SWRC operates the Walnut Gulch Experimental Watershed (WGEW) in southeastern Arizona as an outdoor laboratory for studying semiarid rangeland hydrologic, ecosystem, climate, and erosion processes.

WGEW is currently contributing meteorological data from 4 stations to the NAL data repository.

Long-term Agro-ecosystem Research Initiative

LTAR Walnut Gulch Experimental Watershed Lucky Hills Phenocam

A stationary camera overlooking the Lucky Hills sub-watershed in the Walnut Gulch Experimental Watershed used to track vegetation phenology (RGB and IR imagery). Images are taken every 30 minutes between 4:00am and 10:30pm local standard time.

A link to the Phenocam's network FAQ:

Long-term Agro-ecosystem Research Initiative

Walnut Gulch Experimental Watershed, Arizona (Precipitation)

An extensive precipitation database at the 149 km2 Walnut Gulch Experimental Watershed (WGEW) has been developed over the past 53 years with the first records starting in August 1953 and continuing to the present. The WGEW is a tributary of the San Pedro River, surrounds…

Long-term Agro-ecosystem Research Initiative

Walnut Gulch Experimental Watershed, Arizona (Runoff)

The Walnut Gulch Experimental Watershed (WGEW) runoff database has the longest period of record of runoff in the world for a semiarid location, with data collection beginning in 1953. Runoff occurs at Walnut Gulch primarily as a result of convective thunderstorms during the months of…

Long-term Agro-ecosystem Research Initiative

Walnut Gulch Experimental Watershed, Arizona (Meteorologic)

The Southwest Watershed Research Center (SWRC) has operated Walnut Gulch Experimental Watershed (WGEW), located in the vicinity of Tombstone, Arizona, for more than 50 years. A 17 year (1990-2006) meteorological and soil hydrology database has been established by the USDA Agricultural Research Service, SWRC. Data…

Long-term Agro-ecosystem Research Initiative

Walnut Gulch Experimental Watershed, Arizona (Sediment)

The Walnut Gulch Experimental Watershed (WGEW) sediment collection program, established in 1953, provides event-based data for semiarid rangeland erosion, sediment transport, and yield research. Sediment loads carried through the channel network on the WGEW are high, but are typical of semiarid rangelands, and are influenced…

Long-term Agro-ecosystem Research Initiative