The Cesium-137 Method for Measuring Erosion: Case Study in a Close Arid Basin

Abstract

Fallout ¹³⁷Cs was used to study erosion in a 1-ha closed arid basin created by a railroad embankment in the Mojave Desert. A literature review discovered a web site that gives the start date of Nevada Test Site fallout for any county in the U.S. Calculations showed that the peak ¹³⁷Cs concentration in sediment deposits occurred in 1966 when accumulations in soil were greatest, not in 1963 as is commonly assumed. ¹³⁷Cs calculations using some unverified assumptions yielded soil erosion of 10,000 kg over 46 years, compared to an estimated volume of 15,000 kg of reservoir sediments. The highest erosion rates occurred in the disturbed borrow pit and on steep channel side slopes, while desert pavement areas had deposition. Two main difficulties with ¹³⁷Cs erosion estimates are relating point measurements to larger areas and converting ¹³⁷Cs loss to soil loss.