EROSION AND SEDIMENT YIELD PREDICTION ON FARM FIELDS

MOHAMMAD HASAN HUSSEIN, Purdue University

Abstract

An erosion/sediment yield model designed for farm fields is needed to select Best Management Practices (BMPs) to control erosion and sediment yield. Closed form relationships for detachment, sediment transport and deposition for overland flow areas and field channels were developed. The new model estimates rill and interrill erosion and deposition for concave, convex and complex slopes. The model also estimates erosion, sediment transport and deposition for natural and grassed waterways and terrace channels for restricted and unrestricted outlets. Basic relationships in the new model are similar to those in the CREAMS model. However, the new model replaces the Yalin bed load formula used in CREAMS by a simple formula fitted to the Yalin formula. Unlike CREAMS, the new model simulates each particle type independently in case of multiple particle types, reducing cost and simplifyng the simulation process. A closed form detachment relationships for channel flow were obtained using the Binomial Theorem and similar mathematical techniques. The new model was programmed in Standard Fortran and then compared with the CREAMS model. Program size and simulation cost for the new model are nearly half that for CREAMS. The new model can analyze such effects as slope shape, grass buffer strip, conservation tillage, grassed waterways and other field channels with and without outlet control. When simulating long term records, estimates of sediment yield and sediment enrichment ratio by the two models are essentially the same. However, for single storm events large differences in sediment yield values and sediment enrichment ratio may occur. More specifically, large differences in total sediment yield values may occur when flow shear stress is low or slope profile is steep. Large differences in sediment enrichment ratio may occur when the sand fraction in the soil mass is high.

Degree

Ph.D.

Subject Area

Agronomy

COinS