Fig. 4. Type transfer function (TTF) concentration estimates at d for Day 200 (upper panels) and Day 700 (lower panels) of the simulation period in response to a single, label-recommended application of atrazine for eastern Fresno County. All estimates were made under consideration of spatially uniform annual recharge and for a compliance depth of d = 3 m. (a) TTF Set III (one TTF for each texture). (b) TTF Set IVa (two TTFs for each texture, lower estimate). (c) TTF Set IVb (two TTFs for each texture, higher estimate). (I) Simulation Day 200. (II) Simulation Day 700.