Laserfiche WebLink
chosen as 350 ft by 350 ft, the number of rows used in the model domain is 36, and the <br />number of columns used is 52. This grid cell size allows a fine-enough resolution in the <br />resulting head distribution and concentration distribution for an accurate analysis, while <br />also maintaining computing time efficiency. Using this grid size gives a Peclet number <br />less than 2, which also limits any artificial spreading (not as a result of the natural <br />system) due to numerical dispersion. <br />Boundary conditions were chosen based on water level measurements from existing wells <br />on the Salazar Ranch, parameters given in the RGDSS model and geological features. <br />The eastern boundary is a no-flow boundary, due to the mountain range located to the <br />east of San Luis. The northern boundary is a general head boundary, with a head value of <br />8,120 ft across the entire boundary. The initial head value on the northern boundary was <br />chosen to be slightly higher than the water level measured at SLM-1 so that the simulated <br />head matched closely to the measured water level at SLM-1. The westerly boundary is a <br />general head boundary with heads decreasing linearly in the southerly direction and <br />corresponding to measured water levels at the SLM-2 and SLM-3 wells. Aquifer <br />parameters in the RGDSS model do not indicate any barrier for flow across the westerly <br />boundary, and simulated head values match closely to measured water levels at the <br />monitoring wells. The southern boundary is a constant head boundary, with head values <br />beginning at 8,057 ft in the easternmost cell and decreasing in the westerly direction. <br />The constant head boundary was chosen because Culebra Creek is located to the south of <br />San Luis and was also chosen as a conservative measure of the amount of water leaving <br />the aquifer from the south end. The boundary conditions were chosen to be consistent <br />with RGDSS model features. <br />A steady-state model was initially created to better understand the dynamics of fluid flow <br />in the area of interest. The steady-state model run calculates water levels that are in <br />equilibrium with the system. This is an essential step in the modeling process because <br />the initial conditions for a transient simulation (starting at the beginning of development) <br />must be an equilibrium condition. The steady-state model was run, and the general <br />layout and results of the steady-state model are shown in Figure 1. <br />f 1?r?? -4-