Climate Impacts on the Rainfall Erosivity R in the Revised Universal Soil Loss Equation (RUSLE)

Abstract Submission: Knowing the soil loss on a construction site drives the size of the sediment pond and its maintenance frequency, and it may affect the ability of vegetation to establish prior to soil washout. In addition, excess erosion potentially adds to the cost of regrading and cleaning out of storm-water pipes to the construction project. Therefore, controlling erosion at the source through the proper selection of control practices is both legally required and good economic practice. Soil loss is often calculated using the Revised Universal Soil Loss Equation (RUSLE). It is the Rainfall Erosivity/Energy R that is impacted by climate change. R can be calculated using several methods. This project focuses on the use of the USEPA approximation to the original USDA equations because the input data to calculate R for individual storms are only the total storm depth and total storm duration. A preliminary analysis of the impact of climate change on R in Pennsylvania shows that in half of the six cities whose rainfall history was analyzed, the number of storm events increased slightly and there was a significant increase in R. In the other cities, R increased but the number of storm events per year did not increase, indicating that the change in R is driven by the increase in precipitation in the same duration, e.g., more intense storm events. This work is being extended currently to the region east of the Rocky Mountains. The results are being compared with the updated maps from other research teams who are using the traditional USDA calculation of R to determine whether the US EPA approximation is still valid.

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