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