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SENT BY ~ ~17-97 ~ 15 ~ 30 ; I NDFPE7VDE7dC[: M I N I ~ 303 832 8106. # 4 The leakage estimating technique was, therefore, used as a guideline ro etirneu the Cresson Project LVSCS pumping rcquirerra:nts under various probability stx~ttarios. The resulting estimates were the basis for the present LVSCS pump specifications at the Cresson Valley Leach Facility. 'Ibe Appliration for Amendment Number 6 repored the range of flow rates thaz might be espocted fur variotu cotdidence levels, where the confidence Levels were based on the probabilities of the defxw varying in size and locadon. Using different confidence levels, the Application suggested actions thaz would be taken when the selectW confidence levels were met. If Flows were relatively high, the described objw;tive was to maintain the flow rata and aoludon levels at acceptable rates and levels (stx page 633 of Exhibit S, Volttroe I). The LVSCS was designed by CCB:V to maintain acceptable levels considering the dtickness of the LVSCS gravel, which provides storage sad transmission capabilities for Fluid, and considering the sirrspecific pumping wpabilitiea of the LVSCS. The phrase "atceptable flow rates sad solution levels" refers to the ability m maintain a minimal head oa the lower wmpvsiu liner system and to thereby avoid saturating the full thickness of LVSCS gravel; which avoids transmitting pressure from a substantial fluid column in the overlying PLS to the lower cot~osite liner system. "The estimates of rates that solutions could be anricipa[ed to orr,~r were not, 1rt themselves, a limit. Rather, they were design criteria. The LVSCS, lII its eottrcty (i.e., with ics configuration and pumps), was otu of the safeguards, and both LVSCSs are operating well and in eotttpliaace with the containrttazt criteria of CC&V's pertni[. la the context of operating a lined system, such as a land disposal trait or the Cresson Valley Ixach Faciliry, the dtcnretiral estimating technique was developed prior to use for the Crcssoa Project to assist in storage of solution within an entire mntai»tnmt system; that is, to wntrol leakage from an eatim system, to the extent technially feuible. Speciftwlly, the results of the estimating technique did not. take into account the lowernost litter system, which could resist the pressure maz could be applied and by fluid flow in the drainage system. In the case of CC&V's Cresson Valley Leach Facility, the "entire facility" is the double and triple lined system, as that system is. ultimately, monitored at or near the referenced permit boundary. The wmposite liner, of worse, underlies the LVSCS and may have no imperfections. CC&V, with the assis[ance of Golder Associates, has furthrr examined the information generated to date for LVSCS of Phase 1! for purpose of assessing the adequacy of the design sad operation of the fluid removal system- The data set is the Office's possession covering the period 02/11/97 through 04/03/97 provided the basis for CC&V's examination. These data are provided as Attachmcvt 1. The Attachrrcn[ also lists me more recent ratasurcmenrs which art not included in du computations. These recem data repeat heads and flows that are well represen[ed iu rlre data that were used. By way of explanation, the LVSCS flow rates sad the pregnant solution depths (or heads) iu that data base were used. The flow rates were cotrtpttted for the daily (24-hour) periods by apportioning the cvraulative flow quantities rewrded by CC&V a[ a single point in time to the preceding and currtnt da./s, with the apportionment hosed on the time az which the cumulative reading was rnade. The flow rates calculated from the cumulative readings were considered more accurate than the instantaneous flow rates because the flow raw fluctuates as a ratdt of the large capacity of the putups and the shallow fluid depths in the LVSGS. Ia contrast, the PLS solution head changes ]as rapidly and the instantaneous readings aprteemt levels over longer time periods. Apportionment was conducted [o better relate the flows to a calendar day tau. However, the resulting daily (24 hour) slows were compared m the daily flow compered from the instantaneous flow tau reading for quality control purposes. The correspondence hetween the two flow measuttrr~its was decried acceptable. The pregnant soludon depth in the PLS used for assrasmrnt was the arithmetic average of the daily instantaneous readings read at pregttmt pumps, Tlicre generally are three depth readouts available for averaging. From the review of a graph of the LVSCS flow (in gpm) versus pregnant solution bead (in fat). CC&V confirmed that dtC initial flow measurements, which were made with a flow meter with what tamed out [o be an undersiud rating until 2/20/97, were less than they likely should have beet[ when compared m subsequent end rmre rertnt measurements. The graph using these flow don and all others is provided as Attachment 2. The first four flow reading: made wldr the uadcraized flosvmeter were cotuldercd to Ire too low to lx accurate and, therefoic they were removed from the don base for subsequent analyses. Atnchinent 3 is the same Praph of flow versus heed with the fore points removed (i.e., "revised"). The undersized teeter initially installed was rermvad soon afro its lack of capacity was suspected. In its place, the meter used undl then az Phase [was iaatallod. This larger capacity flow