Laserfiche WebLink
<br />OQQon <br /> <br />" <br /> <br />2. CREST case. - Projected depletion schedule plus the CREST Program and <br />a basinwide operational program. The CREST Program ran from 1986 to 1990, <br />generating 340,000 acre-feet annually. The operational program started <br />immediately in 1991, with an average 1.43 million acre-feet per year <br />generated. No additional Upper Basin depletions were scheduled. <br /> <br />3. WQIP case. - Projected depletion schedule with all of the presently <br />envisioned USBR and USDA Water Quality Improvement Project units coming on <br />line at the reported schedule, except where duplications have appeared <br />between USBR and USDA projects. Crystal Geyser, Colorado River Indian <br />Reservation, LaVerkin Springs, Lower Virgin River, and the second phase of <br />Lower Gunnison Basin and Uinta Basin units were not included in the <br />projected implementation schedule. <br /> <br />4. CREST and WQIP case. - All of the above. <br /> <br />The hydrology that was used was the 1906 through 1978 virgin flow data base, <br />with an average 15 million acre-feet at Lee Ferry and a total basin yield <br />of 16.2 million acre-feet. <br /> <br />Figure 9 shows that without any salinity control projects in place under <br />median hydrology conditions, the average salinity at Imperial Dam would <br />exceed the numeric criteria by 1989, and continue to rise until approxi- <br />mately 2020, at which point the average would stabilize around 1100 mg/L. <br />The second curve shows that under the CREST case the salinity would still <br />exceed the TDS numeric criteria by 1990 and would increase uniformly to over <br />1000 mg/L by 2020. The third curve shows that under the WQIP case, the <br />average river salinity would approach the numeric criteria by 1995, and <br />fluctuate around that level until 2015, at which time it would rise to a new <br />equilibrium point of about 900 to 910. The fourth curve displays the com- <br />bined effect of the CREST and the operational program and the WQIP case <br />programs, which, if all delivered 100 percent of their potential, would serve <br />to keep the average salinity at Imperial below 820 mg/L out to the year 2020. <br />If the salinity concentration levels were maintained at the 820 mg/L level, <br />the projected increases in damages in the lower basin would not occur 75 percent <br />of the time, resulting in a reduction of damages in the United States. <br /> <br />Figure 10 shows the high probabilities of exceeding the TDS numeric criteria <br />standards without WQIP case in the 3 years of 1990, 2000, and 2010 time <br />frames. Figure 11 shows that even with the full WQIP in place and no snow- <br />pack enhancement, there is a 40 percent probability of exceeding the TDS <br />numeric criteria standard in 1990, and a 52 percent probability of exceeding <br />the TDS numeric criteria standard in 2000 and 2010. Figure 12 shows approxi- <br />matelya 25 percent probability of exceeding the TDS numeric criteria standard <br />in 2000 and 2010 with WQIP and basin-wide snowpack enhancement program in <br />place. <br /> <br />Thus, as we move into the next 30 years of development of the basin's <br />resources, there is a 25 percent probability that we will exceed the salinity <br />numeric criteria of 879 mg/L at Imperial Dam on any given year, under the <br />most optimistic projections for the CREST and WQIP case. Any lower program <br />accomplishment will increase the probability of exceeding the TDS numeric <br />criteri a. <br /> <br />14 <br />