HYDRO21836 - Laserfiche WebLink

Home Browse Search

ENVIRONMENT, INC. PADE 2 JULY 22, 200$ to reach potential maximum growth. I then used this IWR number as the calculated PET number for this site. Attached aze two printouts generated by the South Platte Consumptive Use Model. The first (Exhibit 1) is yearly data showing the B-C numbers for 1985 for the two crops. This represented and average year as can be seen on Exhibit 2. These show the baseline data used thru the B-C calculations to ford an average Crop CU number for the mine. The IWR number is the net amount of water the crop would use at this site. Since there were two crops the calculated IWR's had to be weighted by multiplying the IWR for the crop by the area of the crop and dividing it by the total lake area. These were then added together to get the gross BC- Consumptive use for the azea. This number is then used in Tables Al 8t A2 column 3 and represent the CU credit available for drying up the field. The precipitation data came from the Brighton Station and was adjusted and accounted for in Table B of each scenazio, were it was subtracted from the Gross Lake Evaporation. It also shows up for the growing season on Exhibit 1 under column labeled ER. The second table (Exhibit 2) is the ACTUAL CONSUMPTIVE USE for the time span based on 55.92 acres of alfalfa and grass land in the top table and 5.00 acres if grass pasture on the bottom. It was used to determine the average for a span of years. The program rounds these number to the closest whole number and aze usable for compazison purposes only. SCENARIO ONE This scenazio would be triggered only in the unlikely event that Frei's dewatering pumps failed, the pit is allowed to fill with water and Denve[ Water Department does not take over the pit as a reservoir. Assuming a surface area of 55.92 acres t, this scenario would require 37.35 ac-ft of make-up water per yeaz. Tables Ai and $1 replace those previously submitted and aze based on, a 55.92 acre lake area; of which was wvered by 41 acres of alfalfa, and 14,92 acres of grass; Brighton weather information; no gravel production and Denver Water Department supplying water needed for the TSSP. Table AI, is the recap sheet for this mine where the unit numbers are multiplied by 55.92 acres to get ac-inches. It has data from Table Bl, and from Exhibit 1. The last column of this tables shows the amount of water needed each month for makeup water. SCENARIO TWO Frei is done mining and is ready to turn the mine over to Denver Water. The plan is to keep the lake area to 5 acres or less until it iq turned ovor. This aeries of tables is based on there being 5 acres of lake, no gravel mining will take place yeazly and Frei will supply and administer water needed for the mine until Fulton Ditch delivery ends. Make up water for this period will come from Frei's Fulton ditch shazes, which will satisfy the irrigation season water needs. In a dry year these 25 shazes can provide 53.75 acre-ft. The amount of make-up water required during the irrigation season is 2.09 ac-ft. After the Fulton Ditch dries up then Denver will need [o supply the water needs. The amount of make-up water required during the non- irrigation season is 2.03 ac-ft. Therefore, the total needed for the entire year, if the lake is 5.0 acres, is 4.12 ac-ft of water. The Blaney-Griddle information is from Exhibit 1. Table C2 shows the proposed release amounts for each source under sepazate headings. Under each source heading, column 2 is the amount of water needed in any given month. Column 1 is calculated by taking the distance from the source to the South Platte River times 0.2546 times the amount of water needed (transpo~ta- tion losses). Column 3 is the sum of Column 1 and Column 2 and represents the amount of