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c 1_NVIRONMENT, INC. ~ ~~ ~ ~ ~ ~ ~ ~~ ~ ~ PAgE 2 JULY 22, 10Q8~ - ~, the crop to reach potential maximum growth. I then itse¢ this IWIt number as the calculated PET number for this eige, Attached are two printouts generated by the South Platte,COnsumptive Use Model. The first (Exhibit 1~ is yearly. data showing the B-C numbers from 19'79 "to 1991. These aze the years from when Suburbatt purchased the property to when,mining began. These show the baseline data used thru the $-C calculatioac to End an average Crap CU number for the mine. The IWR number is the net amount of water the c;op would use at this site. The second table (Exhibit 2) is the ACTUAL CON$UMPTIVE.USE for the time span based on 100 acres of alfalfa land in the top table and 25 acres: iri the bottom. Each monthly number was arrived at by toe following formula, (IWR"100iac)T(12 ,in/R); -This number is then used in Tables At & 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 ycenprio, were it was subtracted from the Gross,Lake Evaporation. It also shows up for the: growing season on Exhibit 1 under column labeled ER. SCENARIO ONE This scenario woyid be triggered only in the tmlikely event that Suburban's dewatering pumps failed, mining activities cease, the pit is allowed to fi11 with water and Denver Water Department does not take over the pit as a reservoir, Assuming a surface area of 100 acres f, this scenario would require 57.5 ac-ft of make-up water per year. Attached is a letter from Denver Water confirming its agreement to lease Suburban this water in the unlikely event that it was required. Tables At and Bi replace those previously submitted and.aze based on, a 100 acre lake azea, 100 acres of alfalfa; Brighton weather information, no gravel production and Denver Water Department suPPIY1n8 water needed for the TSSP. Table fit, is the recap sheet for this mine where the unit nwnbers'are multiplied by 100 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 Suburban hag yntil 2006 to be done mining. The plan is to keep.the lake area to 25 acres or less until mining ig done. This series of tables is based"Vn there being 25 acres of lake, 250,000 tons of gravel will be mined yearly and Suburban will"supply and administer water needed for the mute until mining ends. This.inclydes industrial needs, lasses with product and lake evaporation. Make up water will come from two sources. Suburban's Burlington-Wellington paired ditch shares, which will satisfy Suburban's.irrigation season water needs. In a dry year these 19 shares can provide 41.62 acre-ft. The amount of make-up water required during the irrigation season is 7.75 ar-ft.. For wintet itionths, Suburban can use part of their 7.5 shares of FRICO (Standley Lake) water (34 ac-R minimum). The amount of make-up water required during the non-irrigation season is 11.07 ac-tt. Therefore, the total needed for the entire year, if the lake is 25.0 acres, is 18.$2 ac-ft of water, The Blaney-Griddle information is from Exhibit 1 page 4, 19$9. Table D2 shows the proposed release amorous for each source under separate headings..Under each source heading, column 2 is the amtxtnt of water needed in any given ritontti: Column 1 is calculated by taking the distance from the source to the South Platte River limas 0,25% times the amount of water needed (tranapoftgiion losses). Column 3 is the sum of Column 1 and Column 2 and represents the amount of water that needs to be diverted into the ditch or creek from the