Accurate model simulation of range sites and improved pasture sites will be valuable for drought assessment and for environmental assessment of various management strategies. In this poster, we will describe research to develop parameters to describe growth of coastal bermudagrass, bahiagrass and several common native warm-season grasses. We will also give validation results for the ALMANAC model, simulating a diverse set of sites in Texas, using published NRCS range yields and bermudagrass and bahiagrass yields.