The effects of Raising Upper Klamath Lake on Water Storage and Distribution between Upper Klamath Lake and Iron Gate Dam. A Preliminary Evaluation Prepared For Klamath Alternative Dispute Resolution Hydrology Steering Committee Prepared By Jonathan L. La Marche Klamath Alternative Dispute Resolution Hydrologist February 7, 2001 1 Summary: The effects of raising Upper Klamath Lake two feet on the distribution of water downstream of the lake were simulated using MODSIM, a water distribution-modeling program. Two different options for raising Klamath Lake were simulated along with a "no raise" option. In the first option, the increased storage space was modeled as if the dikes around the lake were raised. This was entitled the "raising dikes" option and the increase in storage space was not accompanied by an increase in lake surface area. The other option for increasing the storage space was modeled as if the dikes around the lake were breached. In this "breaching dikes" option the increase in storage space was accompanied by an increase in lake surface area. Finally, a "base case" option was simulated which entailed the current operations of the lake and project area (i.e., no raise in maximum lake elevation). For all three simulations the operations of Gerber Reservoir and Clear Lake was considered independent of project, refuge, lake, and downstream demands. ESA (Endangered Species Act) requirements for lake levels and instream flows at Iron Gate were considered. Regulation of junior users upstream of Klamath Lake and tribal claims were not considered in the simulations. This represents current regulatory conditions in the basin. Finally the operations of Upper Klamath Lake, project and refuge demands were modeled as detailed in the Bureau of Reclamation's KPOPsim model. The MODSIM model simulations demonstrated that there is only a slight difference between the "raising dikes" and "breaching dikes" option on lake levels and downstream deliveries. However, results from the "breaching dikes" option are dependent on extrapolating surface area from the existing area/capacity curve as well as the additional storage capacity being accessible for downstream use. Further topographic information regarding the "breaching dikes" option is needed to conclude this result. The model simulations illustrated that for dry years, the increase in storage space in Klamath Lake does not benefit water supply to downstream uses (instream flows, refuge and agriculture deliveries). During these dry years, inflows were insufficient to fill the additional storage space while still meeting downstream requirements. There was a very limited benefit of "carry over" storage between water years. Carry over storage occurred only after very wet years, when agricultural and refuge demands were met, such as in 1975 and 1984. For average and wet years there was a decrease in shortages to both agricultural and refuge lands over the base-case (no raise) scenario. This was accomplished by capturing more of the spring runoff with the additional storage space, while still meeting instream flow requirements at Iron Gate. Shortages to both agricultural and refuge demands were still present during average years as well as some wet years. 2 Introduction: Water rights adjudication is currently underway in the Upper Klamath Basin, located in South Central Oregon, for the settlement of water rights claimed prior to 1909. In order to facilitate negotiations between claimants, the Oregon Water Resources Department (OWRD) implemented a second independent process for the settlement of water rights, known as Alternative Dispute Resolution (ADR). To help the ADR participants understand how the different claimants and users interact, a water distribution model was developed for the Upper Klamath Basin (above Iron Gate Dam) using MODSIM software. The model simulates how different water users interact in the basin based on claimed and permitted usage, reservoir operations, and historical climatic and flow conditions. The model is a water accounting program based on the interaction of instream flows and demands in a stream network. The program automatically routes water to demands in order of their priority date and subject to streamflow and network configuration constraints. It allows for the simulation of competing demands in different regions that share a common downstream drainage point. In addition, the model can balance upstream and downstream uses, based on priority dates, in order to meet lake or reservoir levels. The basic model inputs are 1) demands (both instream and consumptive), 2) stream flows (e.g., historical inflows to Klamath Lake), 3) and reservoir (or lake) parameters (i.e., area/capacity curves, operational curves, storage claims, etc.). In response to a request made by a Klamath Alternative Dispute Resolution member, the effects of increasing the storage space of Klamath Lake on the supply and distribution of water between Upper Klamath Lake and Iron Gate Dam was simulated using the MODSIM program. There are two proposals for increasing the storage space in Klamath Lake, which is currently at 486,800 acre-feet active capacity with a corresponding area of 77,593 acres. Both entail a two-foot increase in lake elevation either by 1) raising the existing dikes and maintaining the current shoreline and surface area or 2) breaching existing dikes and allowing the adjacent lands to flood. Option 1 would increase the active storage capacity to an estimated 657,500 acre-feet without increasing the surface area. Option 2 would increase the active storage capacity to an estimated 661,200 acre-feet while increasing the surface area. Extrapolating the existing area/capacity curve, option 2 would lead to an estimated 4000 acres of additional lake surface area over the current maximum area. Some basic background hydrologic data is as follows. The average annual inflow into the lake between 1961 and 1998 is 1,350,000 acre-feet, with a minimum inflow of 578,000 acre-feet and a maximum inflow of 2,115,000 acre-feet. The average estimated lake evaporation over the same period of record is 3.5 acre-feet/acre and the average precipitation is 13.5 inches. 3 Approach: To determine the effects of increasing the storage capacity of Klamath Lake on water distribution, three simulations were run: 1. base case — current lake operations and downstream water distribution. 2. raised dikes — water storage and distribution associated with increasing storage of Klamath Lake by two vertical feet without an associated increase in surface area (i.e., raising dikes around Klamath Lake). 3. breaching dikes — water storage and distribution associated with increasing storage of Klamath Lake by two feet with a linear extrapolation in surface area (i.e., breaching dikes around Klamath Lake). All three simulations incorporate demands for the project agricultural and refuge areas as detailed in KPOPsim (Klamath Project Operational simulations model), historical inflows to Klamath Lake, ESA (Endangered Species Act) flow requirements for Klamath River at Iron Gate (see Appendix A), and ESA lake level requirements for Upper Klamath Lake (see Appendix A). In addition, the operations of Klamath Lake simulated in MODSIM were calibrated to mimic operations as detailed in the KPOP model ("base case scenario), except on a monthly time step (see Appendix B). The operational rules in both MODSIM and KPOP are such that the following conditions are met in order: 1. Klamath Lake minimum monthly lake elevations. 2. Instream Flow Requirements at Iron Gate. 3. Irrigation Deliveries to Agricultural Lands 4. Water Deliveries to the Refuges In addition to these constraints, a flood control limit was also used to limit the maximum monthly lake level for Upper Klamath Lake. The flood limit was increased by two feet for both the "raised dikes" and "breached dikes" simulations. In all simulations, the flood control limit and minimum lake elevations defined the operational envelope in which the lake was simulated to operate (Figures 1a and 1b). Within the operational envelope, the remaining conditions (2-4 listed above) were targeted in the order described above. If instream flows at Iron Gate were not met, then deliveries to agricultural lands and the refuges were curtailed. The use of monthly hydrologic states (i.e., wet, average, dry water month types) were used to spread projected agriculture and refuge shortages over the irrigation season as opposed to lumping the total shortage into one or two months. Hydrologic states were defined through a combination of historical inflows to the lake and the simulated lake contents. 4 Evaporation from and direct precipitation onto Upper Klamath Lake were also incorporated into the model. If the lake surface area increases due to higher elevation requirements, MODSIM includes the higher evaporation losses and precipitation inputs in the simulation. Thus, the model is able to simulate differences in stored and distributed water associated with an increase in surface area related to the increased storage of Klamath Lake. All simulations were run for the same time period 1961-1997, and all used the corresponding historic lake inflows, and project and refuge demands (as depicted in KPOPsim). Gerber and Clear Lake reservoir operations were not included in the simulation. Therefore, the operation of Gerber and Clear Lake reservoir for irrigation of project lands or to meet downstream flow requirements was not considered. Finally all tribal water right claims (both lake and instream) as well as enforcement of junior water rights upstream of Klamath Lake to meet downstream demands were not considered. This represents current water right enforcement in the Upper Klamath basin. 5 Operational Envelope for Klamath Lake for Base Case (no-raise) 4144 Lake Elevation (ft) 4143 4142 4141 4140 4139 4138 4137 ESA Limit SE P G A U L JU N JU Y M A A PR R M A FE B N JA D EC V N O O CT 4136 Flood Limit ESA Limit SE P G A U L JU N JU Y M A A PR R M A FE B N JA D EC N O V 4146 4145 4144 4143 4142 4141 4140 4139 4138 4137 4136 O CT Lake Elevation (ft) Operational Envelope for Klamath Lake for 2ft Increase in Lake Storage (raised or breeched dikes) Flood Limit Figures 1 and 2: Upper Klamath Lake Operational Envelope for Base-Case Scenarios (top) and Increase Storage (bottom) 6 Results/Discussion: Results from the simulations are segregated into four sections: 1) Agricultural Shortages, 2) Refuge Shortages, 3) Iron Gate Flows, and 4) Lake Levels. The results are presented both as an annual amount for each year in the simulation period and summarized for year types (wet, average, dry). The classification of year types (Table 1) was based on exceedance levels for total water year inflows into Klamath Lake (i.e., Oct-Sept). The water year type classification differs from previous ADR studies of tributaries above Klamath Lake (based on spring and summer flows) to include fall and winter flows. This new classification considers the storage capacity in Klamath Lake to capture inflows over the entire year. Results for the four sections are discussed below in each sub-section. Table 1 Wet Year Types Average Dry 1965 1963 1961 1971 1972 1974 1975 1978 1982 1983 1984 1986 1996 1997 1964 1966 1967 1969 1970 1973 1976 1980 1985 1989 1993 1995 1962 1968 1977 1979 1981 1987 1988 1990 1991 1992 1994 Agriculture Results: The results for the three simulations on annual agricultural shortages over the simulation period are shown in Figure 3. The "base case" simulation demonstrates the agriculture shortages associated with meeting the current ESA lake and instream requirements. In general terms, these annual agricultural shortages are reduced with the increased storage capacity. This is particularly true for average to wet water years, due to the additional storage capacity of Klamath Lake to capture high spring flows (a portion of these flows are normally spilled with the current lake capacity). However, for dry years (e.g., 1992), the increase storage capacity has essentially no affect on agricultural shortages (Figure 3). During dry years, the inflows into Klamath Lake are not sufficient to take advantage of the additional capacity of Klamath Lake. This is shown in the simulated lake levels for 1992 (Figure 4). The lake levels for the "base-case" and "raised dikes" options are identical in 1992. This is because instream flow requirements for Iron Gate in 1992 (Figure 5) are not being met. Since this requirement has a higher priority than filling the added capacity in Klamath Lake, no water above the minimum lake levels is being stored and the simulated "raised dikes" lake levels are identical to the base case. On the other hand, during the runoff in water year 1993, minimum flows at Iron Gate are met (Figure 5). Therefore, additional water is stored in the "raised dikes" option (Figure 4), demonstrating the benefit of the additional capacity in capturing more of the spring runoff. 7 Effects of Klamath Lake Storage Modifications on Project Agriculture Deliveries given ESA constraints 450000 400000 350000 Ag Shortages 300000 250000 200000 150000 100000 50000 Increased Storage by Raising Dikes Increased Storage by Breaching Dikes 1997 1995 1993 1991 1989 1987 1985 1983 1981 1979 1977 1975 1973 1971 1969 1967 1965 1963 1961 0 Base Case (No Raise) Figure 3: Agricultural Shortages with and without Klamath Lake Modifications Simulated Klamath Lake Levels for Base Case and Raising Klamath Lake 2ft 4146 4145 Lake Levels 4144 4143 4142 4141 4140 Base Case 4 1993 10 1993 4 1992 10 1992 4139 Straight Raise (2ft) Figure 4: Simulated Klamath Lake Levels for Dry and Average years with and without Increase Lake Capacity 8 450000 400000 Flows at Iron Gate (ac-ft) 350000 300000 250000 200000 150000 100000 50000 no raise raised dikes 10 1994 4 1993 10 1993 4 1992 10 1992 0 min flow at Iron Gate Figure 5: Simulated instream flows at Iron Gate for Dry (1992) and Average (1993) water years. There is only a limited benefit due to carry over storage between years. For example 1986 was a wet year with slight shortages to agriculture deliveries under the "raised dikes" simulation (Figure 3). The following year, 1987, was dry. However, the shortages associated with the increased storage option are almost equal to the base case. This demonstrates the limited capacity of the lake to carry-over water from wet years to drier ones. Only if all downstream demands and ESA requirements are met (e.g., 1984), is there a carry over benefit for the following year (e.g., 1985). There is only a slight difference in agricultural shortages between the raising Klamath Lake by breaching or raising dikes simulations for any year type (Figure 6a, b & c). This difference is due to the increase in surface area and corresponding evaporation associated with breaching dikes, which is offset by a small increase in storage capacity as well as the increased lake surface area to capture precipitation. However, the difference between the two increase storage options is very small and most likely within the model uncertainty. Differences between the two scenarios may be greater if the surface area increase associated with the "breaching dikes" option is greater than estimated. Figures 6a through 6c show that for wet type years, the increase storage capacity reduces agriculture shortages by roughly 60,000 acre feet on average over the no-raise simulation. For average type years the shortages are reduced by roughly 75,000 acre feet on average with the increase storage. However, as previously stated, during dry years there is essentially no benefit by increasing the capacity of Klamath Lake. 9 Comparison of Agriculture Shortages with Klamath Lake Modifications for Wet Years and ESA constraints 250000 Ag Shortages (ac-ft) 200000 150000 100000 50000 0 Increase in Storage by Breaching Dikes Increase in Storage by Raising Dikes Base Case Simulation Figure 6a Mean Agriculture Shortages Associated with Klamath Lake Storage Modifications and ESA Constraints for Wet Years. Comparison of Agriculture Shortages with Klamath Lake Modifications for Average Years and ESA constraints 250000 Ag Shortages (ac-ft) 200000 150000 100000 50000 0 Increase in Storage by Breaching Dikes Increase in Storage by Raising Dikes Base Case Simulation Figure 6b Mean Agriculture Shortages Associated with Klamath Lake Storage Modifications and ESA Constraints for Average Years. 10 Comparison of Agriculture Shortages with Klamath Lake Modifications for Dry Years and ESA constraints 350000 300000 Ag Shortages (ac-ft) 250000 200000 150000 100000 50000 0 Increase in Storage by Breaching Dikes Increase in Storage by Raising Dikes Base Case Simulation Figure 6c: Mean Agriculture Shortages Associated with Klamath Lake Storage Modifications and ESA Constraints for Dry (bottom) Years. Refuge Results: The results for the three simulations on annual refuge shortages (Figure 7) over the simulation period are similar to those for the agriculture shortages. Shortages to the refuge are significantly reduced or eliminated for wet and average years, while there is little benefit of the added storage capacity for dry years (Figure 8a, 8b, and 8c). Again, this trend is due to the additional storage capacity of Klamath Lake to capture spring flows, which may have been spilled during average and wet years under the current lake capacity. However, for dry years (e.g., 1977), the increase storage capacity has essentially no effect to reduce the refuge shortages, because inflows do not fill the additional capacity. 11 Effects of Klamath Lake Storage Modifications on Refuge Deliveries given ESA constraints 30000 Refuge Shortages 25000 20000 15000 10000 5000 Increased Storage by Raising Dikes Increased Storage by Breaching Dikes 1995 1993 1991 1989 1987 1985 1983 1981 1979 1977 1975 1973 1971 1969 1967 1965 1963 1961 0 Base Case (No Raise) Figure 7: Refuge Shortages with and without Klamath Lake Modifications Comparison of Refuge Shortages with Klamath Lake Modifications and ESA constraints for Wet Years 12000 10000 Shortages (ac-ft) 8000 6000 4000 2000 0 Increase in Storage by Breaching Dikes Increase in Storage by Raising Dikes Base Case Simulation Figure 8a: Mean Refuge Shortages Associated with Klamath Lake Storage Modifications and ESA Constraints for Wet Years. 12 Comparison of Refuge Shortages with Klamath Lake Modifications and ESA constraints for Average Years 25000 Shortages (ac-ft) 20000 15000 10000 5000 0 Increase in Storage by Breaching Dikes Increase in Storage by Raising Dikes Base Case Simulation Comparison of Refuge Shortages with Klamath Lake Modifications for Dry Years 25000 Shortages (ac-ft) 20000 15000 10000 5000 0 Increase in Storage by Breaching Dikes Increase in Storage by Raising Dikes Base Case Simulation Figure 8b & 8c: Mean Agriculture Shortages Associated with Klamath Lake Storage Modifications and ESA Constraints for Average (Top) and Dry (Bottom) Years. 13 Iron Gate Flows: The results for annual flows at Iron Gate are generally the reverse of those for the agriculture and refuge shortages (Figure 9). For wet years the increased storage simulations decrease annual flows at Iron Gate compared to the base case. However, the annual discharge at Iron Gate is still well above the minimum annual flow (the sum of the minimum monthly flows to meet ESA requirements). This is because no additional inflows are stored in Klamath Lake above the ESA requirement, unless the instream ESA requirements at Iron Gate are met. For dry years there is essentially no difference in flows at Iron Gate associated with the increase storage (Figure 10a, 10b, 10c). Again this is due to the lack of inflows to be stored during dry years (Figure 4). As previously mentioned, this also translates to no additional water stored to meet agriculture and refuge demands during dry years. Effects of Klamath Lake Modifications on Iron Gate Flows given ESA constraints 2750000 Annual Iron Gate Flows (ac-ft) 2550000 2350000 2150000 1950000 1750000 1550000 1350000 1150000 950000 Increased Storage by Raising Dikes Base Case (No Raise) 1997 1995 1993 1991 1989 1987 1985 1983 1981 1979 1977 1975 1973 1971 1969 1967 1965 1963 1961 750000 Increased Storage by Breaching Dikes Minimum Annual Flow at Iron Gate Figure 9: Annual Discharge at Iron Gate with and without Klamath Lake Modifications 14 Comparison of Iron Gate Flows with Klamath Lake Storage Modifications and ESA constraints for Wet Years 2400000 2200000 Discharge (ac-ft) 2000000 1800000 1600000 1400000 1200000 1000000 Increase in Storage by Breaching Dikes Increase in Storage by Raising Dikes Base Case Simulation Comparison of Iron Gate Flows with Klamath Lake Storage Modifications and ESA constraints during Average Years 1800000 1700000 Discharge (ac-ft) 1600000 1500000 1400000 1300000 1200000 1100000 1000000 Increase in Storage by Breaching Dikes Increase in Storage by Raising Dikes Base Case Simulation Figure 10a & 10b: Mean Annual Discharge at Iron Gate Associated with Klamath Lake Storage Modifications and ESA Constraints for Wet (Top) and Average (Bottom) Years. 15 Comparison of Iron Gate Flows with Klamath Lake Storage Modifications and ESA constraints during Dry Years 1250000 Discharge (ac-ft) 1200000 1150000 1100000 1050000 1000000 Increase in Storage by Breaching Dikes Increase in Storage by Raising Dikes Base Case Simulation Figure 10c: Mean Annual Discharge at Iron Gate Associated with Klamath Lake Storage Modifications and ESA Constraints for Dry Years. Lake Levels: The results for lake levels support the results for the other categories discussed above. For dry year types, there is very little difference in lake levels between the base case and increased storage simulations (Figure 11a). During these dry years there is simply not enough inflows to Klamath Lake to fill the lake to capacity while meeting downstream needs. Thus the benefit of additional storage space during dry years to capture spring runoff for later use during the summer is very small to non-existent. For an average year, the difference in lake elevations (Figure 11b) demonstrates the increase capacity to capture spring runoff for benefit during the summer (Figure 12). This is shown to a greater extent for wet years (Figure 11c). 16 Comparison of Simulated Lake Levels with Klamath Lake Modifications and ESA constraints for Dry Years 4143.0 Lake Elevation (ft) 4142.0 4141.0 4140.0 4139.0 4138.0 4137.0 OCT NOV Base Case Simulation DEC JAN FEB MAR APR MAY Increase in Storage by Raising Dikes JUN JUL AUG SEP Increase in Storage by Breaching Dikes Comparison of Simulated Lake Levels with Klamath Lake Modifications and ESA constraints for Average Years 4144.0 4143.0 Lake Elevation (ft) 4142.0 4141.0 4140.0 4139.0 4138.0 4137.0 4136.0 OCT NOV Base Case Simulation DEC JAN FEB MAR APR Increase in Storage by Raising Dikes MAY JUN JUL AUG SEP Increase in Storage by Breaching Dikes Figure 11a & b: Simulated Mean Lake Levels Associated with Klamath Lake Storage Modifications and ESA Constraints for Dry (Top) and Average (Bottom) Years 17 Comparison of Simulated Lake Levels with Klamath Lake Modifications and ESA constraints for Wet Years 4146.0 4145.0 Lake Elevation (ft) 4144.0 4143.0 4142.0 4141.0 4140.0 4139.0 4138.0 4137.0 OCT NOV Base Case Simulation DEC JAN FEB MAR APR MAY Increase in Storage by Raising Dikes JUN JUL AUG SEP Increase in Storage by Breaching Dikes Figure 11c: Simulated Mean Lake Levels Associated with Klamath Lake Storage Modifications and ESA Constraints for Wet Years Simulated Klamath Lake Levels for Base Case and the Raise Dikes Options 4145 4144 Lake Levels 4143 4142 4141 4140 10 1970 4 1970 4139 Base Case "raise dikes" Figure 12: Example of increase lake capacity capturing additional runoff over current capacity (base case). 18 Conclusion: The MODSIM simulations demonstrate that there is a negligible benefit to the supply and distribution of water from increased storage space in Klamath Lake during dry years. The additional storage is not filled due to low inflows into Klamath Lake and downstream requirements. However, there is some benefit for the added storage to meet downstream needs during wet and average years, when inflows to Klamath Lake are more significant. This is accomplished while still meeting ESA flows at Iron Gate. On the other hand, agriculture and refuge deliveries are curtailed during average years even with the increase in storage, although to a lesser extent than with current available storage (i.e., the base case scenario). There is some benefit from carryover storage for any year following a very wet water years (e.g., 1976 following 1975). However, for the majority of years, when agriculture and refuge shortages are present, there is no carry over storage benefit. The simulated difference between raising or breaching dikes on the supply and distribution of water between Klamath Lake and Iron Gate Dam is minimal. However, additional information regarding the increase in surface area, capacity, and any inactive storage space associated with the "breaching dikes" option might change this result. 19 Appendix A 1999 BOP for Klamath Lake Levels and Instream Flows at Iron Gate (i.e., ESA Requirements) Month October November December January February March April May June July August September Minimum Flow at Iron Gate (cfs) 1476 1688 2082 2421 3008 3073 3307 3056 2249 1714 1346 1395 20 Minimum Lake Level (ft) 4139.34 4139.66 4140.00 4141.01 4141.74 4142.32 4142.60 4142.60 4141.93 4139.00 4139.00 4139.00 APPENDIX B MODSIM/KPOP COMPARISON FOR BASE CASE (NO-RAISE) SCENARIO 4143.5 4143 4142.5 Lake Levels (ft) 4142 4141.5 4141 4140.5 4140 4139.5 MODSIM Lake Levels 4 1995 10 1995 4 1994 10 1994 4 1993 10 1993 4 1992 10 1992 4 1991 10 1991 4139 KPOP Lake Levels 90000 80000 70000 50000 40000 30000 20000 10000 MODSIMs 21 KPOP 4 1995 10 1995 4 1994 10 1994 4 1993 10 1993 4 1992 10 1992 4 1991 0 10 1991 Ag Shortages (ac-ft) 60000 MODSIM 22 KPOP 4 1995 10 1995 4 1994 10 1994 4 1993 10 1993 4 1992 10 1992 4 1991 10 1991 Flows at Iron Gate (ac-ft) 450000 400000 350000 300000 250000 200000 150000 100000 50000 0 MODSIMs 23 KPOP 70000 60000 50000 40000 30000 20000 10000 0 4 1974 10 1974 4 1973 10 1973 4 1972 10 1972 4 1971 10 1971 4 1975 80000 4 1975 90000 10 1975 KPOP Lake Levels 10 1975 4 1974 MODSIM Lake Levels 10 1974 4 1973 10 1973 4 1972 10 1972 4 1971 10 1971 Ag Shortages Lake Levels 4144 4143.5 4143 4142.5 4142 4141.5 4141 4140.5 4140 4139.5 4139 MODSIM 24 KPOP 4 1975 10 1975 4 1974 10 1974 4 1973 10 1973 4 1972 10 1972 4 1971 10 1971 Flows at Iron Gate 700000 600000 500000 400000 300000 200000 100000 0