Additional information regarding the chosen geologic framework of the Applicant's model was extracted and analyzed. The results of such supplementary analysis are presented in Figures 4-34. Each figure in this set of nine from Figure 4-34a through 4-34i is depicted in an identical format. This format consists of three east-west cross-sectional views through the model layers accompanied by a plan-view of the model domain illustrating the specific grid-cell rows through which the cross sections pass. Each of the three cross-sectional frames identify the grid-cell row number and depict the presence and thickness of individual model layers using a color code identified in the legend. Such depictions are based upon elevation values extracted from the input data sets created by the Applicant. The values supplied to individual grid cells are linearly interpolated in order to derive, in a manner similar to Figure 4-4a, a continuous shape for each model layer. In these figures, the model layers are prescribed as active when depicted as color filled. Wherever white space is depicted between layers, an inactive area exists in the model between layers, by prescription.
In a similar manner, Figures 4-35 presents the identical east-west geologic cross-sectional information extracted from the Applicant's model framework. The difference between Figure 4-34 and Figure 4-35 is that in the latter depiction the value prescribed for each grid cell has been maintained as constant across the width of that cell. The resulting castellated shape of each model layer is color filled using the identical layer designation as in Figures 4-34. Once again, the model layers are active when depicted as color filled and where white space is depicted between layers, an inactive area exists in the model between layers, by prescription.
It is useful to consider geologic cross-sectional information, as embodied in the Applicant's ground water model framework, using north-south depictions. This is done in Figures 4-36 and in Figures 4-37 which adopt a format similar to those used for Figures 4-34 and Figures 4-35. Each figure from the set of six figures from Figure 4-36a through 4-36f is depicted in an identical format. This format consists of three north-south cross-sectional views through the same model layers accompanied by a plan view of the model domain illustrating the specific grid-cell columns through which the cross sections pass. In this set of figures, elevation values supplied to individual grid cells are linearly interpolated in order to derive a continuous shape for each model layer wherever it was prescribed to exist. Figures 4-37 presents the identical information using a similar format of six figures, but in a depiction where the value prescribed for each grid cell has been maintained as constant across the width of that cell. The resulting castellated shape of each model layer is color filled using the identical layer designation as in Figures 4-36. Once again, the model layers are active when depicted as color filled and where white space is depicted between layers, an inactive area exists in the model between layers, by prescription. The significance of inactive areas, illustrated by the white spaces indicated for example in Figures 4-36d and 4-37d, chosen by the Applicant is that model layer 2 can instantaneously exchange ground water with model layer 3, by prescription, despite being separated by distances of several thousand feet.
Cross-sections through the model domain were also subjected to analysis regarding layers used in the model framework to represent certain geological formations and units. Analysis revealed that the representation of model layers in the vicinity of streams did not include certain model layers which have been chosen to appear elsewhere in the domain. Figures 4-38 and 4-39 illustrate close-up views of such features on Jefferson Creek about 1.2 miles downstream of the town of Jefferson. Figure 4-38a illustrates an east-west cross section taken through model row 27 using the linear interpolation method and Figure 4-38b illustrates the same cross section using constant thickness values within each grid cell. Similarly, Figures 4-39 present a north-south cross section through model column 32 using identical methods. The stream is connected to the aquifer in Layer 1. In cell (27,32), model layers 2 and 3 are inactive, while layers 4 and 5 are active. Significant impacts due to project pumping occur in layers 4 and 5. However, the absence of active cells in layers 2 and 3 makes the model incapable of communicating these impacts to layer 1. As a result, predicted impacts to the stream in this area is minuscule. Thus, the choice of model layering has governed the model's capability of calculating stream flows and of depletions to such flows caused by the proposed ground water pumping.
Supplementary analysis of the representation of streams in the Applicant's model framework of the South Park ground water system was also conducted. Figures 4-40 were prepared to depict the parameters subjected to such analysis. Figure 4-25g had depicted the stream bed conductance values used in the model. The stream bed conductance is equal to the area of the stream bed times the vertical hydraulic conductivity of the stream bed divided by the stream bed thickness. The area of the stream bed is equal to the length times the average width of the stream bed. Figure 4-40a depicts the prescription of lengths to stream segments within individual model grid cells within the domain. Figure 4-40b similarly depicts the prescriptions of stream widths to model grid cells. Figure 4-40c depicts the assignments of values to hydraulic conductivity of stream-bed sediments. It is of interest to note that for the majority of the streams, a value of exactly 2 feet/day was used for the vertical hydraulic conductivity of the stream. Figures 4-40d and 4-40e depict values of stream slope calculated by two different methods. The upstream difference method uses the difference between the assigned stage in the first upstream cell divided by the distance to calculate a slope, The central difference method uses the assigned stage in the first downstream cell and the first upstream cell divided by the distance, to calculate the slope for the cell in the middle. A number of cells such as the reservoir cells in the stream package are shown with no color in Figures 4-40d and 4-40e. For these cells, no slope appears in the Applicant's files even though a slope could be calculated. For the reservoir cells, the expected slope is zero. Figure 4-40f follows up by depicting the prescribed values of Manning's Coefficient representing the roughness of the stream bed in connection with stream flows. The values of these parameters were prescribed by the Applicant in the model data sets. Grid cells shown without color are again those in which a value is not listed in the Applicant's files.
The values for the slope, Manning's Coefficient and stream width are required to calculate the stage based on the surface water flow rate using the calculated stage feature in MODFLOW's Prudic Stream Package. These values appear in data files produced by the Applicant. However, in the model runs produced by the Applicant, this feature was not invoked.
Supplementary analysis of the model framework concerning the assignment of percent cover components used in calculating ET rates from irrigated lands, was also conducted. Figure 4-41a presents the prescribed values of grid-cell percentages representing irrigated-area fractions. Figure 4-41b depicts the prescribed values of irrigation efficiency in the same grid cells. Figure 4-41c depicts the percentage of native, i.e. phreatophytic, vegetation prescribed in model grid cells. These values are used to produce the percent cover for ET shown in Figure 4-32a. Where the percentage of grid cell irrigated area shown in Figure 4-41a is positive, and the irrigation efficiency shown in Figure 4-41b is also positive, the percent cover for ET is set equal to 24% of the irrigated area shown in Figure 4-41a plus the native ET area shown in Figure 4-41c. Where the percent irrigated area shown in Figure 4-41a is positive, but the irrigation efficiency shown in Figure 4-41b is zero, the percent cover for ET is set equal to the irrigated area shown in Figure 4-41a and the native ET area shown in Figure 4-41c is ignored. Where the percent irrigated area shown in Figure 4-41a is zero, the percent cover for ET is set equal to the native ET area shown in Figure 4-41c and the irrigation efficiency shown in Figure 4-41b is ignored.
The computational use of these prescribed components has led to inconsistencies and errors in the model calculation of vegetative consumptive use by ET and its predicted salvage is attributed only to effects caused by the proposed well pumping.
Supplementary analysis of the model framework regarding representation of the Applicant's storage reservoir was also conducted. Figure 4-41d depicts the reservoir evaporation rate used in the model. Reservoir evaporation is represented using the ET package and is thus treated as if it were ET from ground water. This ET rate, illustrated in Figure 4-41d, denotes the maximum ET rate at which ground water is lost when the water level is either at or above the local ground surface. Further, this prescribed rate is identical from one year to the next, irrespective of the water level and hence surface area attained by the proposed storage reservoir water, and was applied to eleven grid cells in model layer 1. The reservoir area is therefore at most 11,000,000 square feet or 252.5 acres. The reservoir evaporation is represented in the model as occurring from model layer 1.