Modified CREAMS Nutrient Model for Coastal Plain Watersheds

IN evaluating the suitability of the CREAMS model for simulating nutrient yield from Coastal Plain **flatwoods'' watersheds in South Florida, it was determined that assumptions made in developing the model were not valid for the sandy soils prevalent in this region. Conceptual changes to the model led to the development of the CREAMS-WT version which better represents the low phosphorus buffering capacity of these sandy soils. For verification, two watersheds were simulated without calibration: a beef pasture with low nutrient loading, and a dairy watershed with very high nutrient loading. Predicted annual flow-weighted concentrations of total-N and total-P compare closely with observed values for both sites, correctly reflecting the response of these extreme cases of nutrient loading. A sensitivity analysis of new and modified parameters is presented along with comments on estimating parameters.