public static float GetFWater(ISpecies species, float pressurehead) { if (pressurehead < 0 || pressurehead > species.H4()) return 0; else if (pressurehead > species.H3()) return 1 - ((pressurehead - species.H3()) / (species.H4() - species.H3())); else if (pressurehead < species.H2()) return pressurehead / species.H2(); else return 1; }