how much do we have left? coming to terms with the colorado river water availability study annual...
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How Much Do We Have Left?Coming to Terms With the
Colorado River Water Availability Study
Annual Colorado Water WorkshopJuly 21, 2010
How Much Do We Have Left?Coming to Terms With the
Colorado River Water Availability Study
Annual Colorado Water WorkshopJuly 21, 2010
Ben Harding – AMEC Earth and EnvironmentalErin Wilson – Leonard Rice Engineers
Colorado Decision Support System - OverviewColorado Decision Support System - Overview
• Water Management System• Developed by CWCB and Division of Water
Resources • Goal is to provide data/tools to assist in
making informed decisions regarding historic and future use of water
1992 1993 1998 2001 future
Legi
slat
ive
Aut
horiz
atio
n
Initial CRDSS Development
(Gunnison, Yampa, Colorado, San Juan,
Dolores)
RGDSS Development
(Rio Grande)
CRDSS (Enhancements and Extension)
Maintenance & Updates,
Arkansas?
SPDSS Development
(South Platte, North Platte)
Colorado Decision Support SystemColorado Decision Support System
HydroBase
DataManagement
Interfaces
Consumptive Use Model“StateCU”
SurfaceWater Model“StateMod”
User/Operator/
Administrator Input
Results for Decision Makers
GIS Coverages
Consumptive Use Model
StateCU
Surface Water Model
StateMod
Results for
Decision Makers
Alternate Temperature
Physical and Legal Water Availability
Alternate CIR
Alternate HydrologyAlternate
Precipitation
Estimating Water AvailabilityEstimating Water Availability
Findings - TemperatureFindings - Temperature
• Map shows Average of the Five 2040 Projections
• All Five Projections show Temperature Increases
• Increases basin-wide by 3.3 to 3.7 deg F
• Lower elevations show largest increase
• Increase occurs each month of the year
Findings - TemperatureFindings - Temperature
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Tem
pe
ratu
re (D
eg
F)
Gunnison 3SW2040 Average Monthly Temperature
Historical Average
Hot and Wet Projection
Hot and Dry Projection
Warm and Dry Projection
Warm and Wet Projection
Median Projection
Average Annual Climate Projection Temperature Higher than Historical by 1.7 deg F to 5.2 deg F
Five Projection Ave = 3.5 deg F Increase
Findings - TemperatureFindings - Temperature
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Tem
per
atu
re (
Deg
F)
Delta 3E2040 Average Monthly Temperature
Historical Average
Hot and Wet Projection
Hot and Dry Projection
Warm and Dry Projection
Warm and Wet Projection
Median Projection
Average Annual Climate Projection Temperature Higher than Historical by 1.9 deg F to 5.3 deg F
Five Projection Ave = 3.7 deg F Increase
Findings - Winter Precipitation (Nov-Mar)
Findings - Winter Precipitation (Nov-Mar)
• Map shows Average of Five Projections
• Increases basin-wide by 6 to 13 percent
• Increases more in the northern part of the basin
• Increases more at higher elevations
• Shifts from snow to rain in the shoulder months
Findings - Summer Precipitation (Apr-Oct)
Findings - Summer Precipitation (Apr-Oct)
• Decreases basin-wide by 4 to 10 percent
• Wet projections show more precipitation in some summer months than dry projections
• Decreases more in the southern part of the basin
• Decreases less at higher elevations
Findings - PrecipitationFindings - Precipitation
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
1.80
2.00
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Pre
cip
itatio
n (i
nch
es)
Gunnison 3SW2040 Average Monthly Precipitation
Historical Average
Hot and Wet Projection
Hot and Dry Projection
Warm and Dry Projection
Warm and Wet Projection
Median Projection
Average Annual Climate Projection Precipitation Ranges from 9.4 to 11.5 inches (Historical = 10.6 inches)
Five Projection Average Increases by 9% in Winter and Decreases by 8% in Summer
Findings - PrecipitationFindings - Precipitation
0.00
0.20
0.40
0.60
0.80
1.00
1.20
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Pre
cip
itat
ion
(in
ches
)
Delta 3E2040 Average Monthly Precipitation
Historical Average
Hot and Wet Projection
Hot and Dry Projection
Warm and Dry Projection
Warm and Wet Projection
Median Projection
Average Annual Climate Projection Precipitation Ranges from 6.5 to 7.8 inches (Historical = 7.4 inches)
Five Projection Average Increases by 7% in Winter and Decreases by 8.5% in Summer
Findings - Crop Irrigation Requirement
Findings - Crop Irrigation Requirement
• Map shows Average of Five Projections
• Increases basin-wide 2.6 to 6.7 in/yr for pasture grass
• Basin-wide CIR is 20% greater than historical
• Growing season increases basin-wide by 15 to 22 days
• Increases more at lower elevations
Findings - Crop Irrigation RequirementFindings - Crop Irrigation Requirement
0.00
0.20
0.40
0.60
0.80
1.00
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
/Ac
re
Gunnison 3SW2040 Average Monthly CIR (Grass Pasture)
Historical Average
Hot and Wet Projection
Hot and Dry Projection
Warm and Dry Projection
Warm and Wet Projection
Median Projection
Average Annual Climate Model CIR Ranges from 2.33 to 2.62 AF/acre, compared to Historical Average CIR = 2.22 Af/acre
Growing season is extended by 17 days
Findings - Crop Irrigation RequirementFindings - Crop Irrigation Requirement
0.00
0.20
0.40
0.60
0.80
1.00
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
/Ac
re
Delta 3E2040 Average Monthly CIR (Grass Pasture)
Historical Average
Hot and Wet Projection
Hot and Dry Projection
Warm and Dry Projection
Warm and Wet Projection
Median Projection
Average Annual Climate Projection CIR Ranges from 2.75 to 3.30 AF/acre, compared to Historical Average CIR = 2.5 AF/acre
Growing season is extended by 18 days
StateMod Model ComponentsStateMod Model Components
16
Inflow Hydrology – Natural FlowsInflow Hydrology – Natural Flows
• Historical Natural Flows Estimated by Removing the Effects of Man from Gaged Flows• Diversions• Reservoir Contents• Return Flows
• Climate Projected Natural Flows
17
Physical SystemsPhysical Systems
• Diversion Structures– Location on the River– Headgate and Canal Capacities– Return Flow Locations
• Reservoirs– Location on River or Off-Channel– Location of Carrier Ditches– Storage Volume, Outlet Capacities, Account
Size, Area/Capacity Tables
• Instream Flow Reaches– Beginning/Ending of Reach
18
Water DemandsWater Demands
• Irrigation Demands – Full Irrigation Water Requirements from
StateCU (Historical, Based on Climate Projections)
• Municipal and Industrial Demands – Current Use Levels
• Trans-basin Demands– Current Diversions
• Reservoir “Demands” – Reservoir Capacities or Operational Targets
19
Water DemandsWater Demands
• CWCB Instream Flow Demands based on Water Rights
• Reservoir and Trans-basin Bypass Requirements based on Operational Agreements
• Endangered Species Flow Demands based on Flow Targets
20
Administrative ConditionsAdministrative Conditions
• Water Rights (Direct, Storage, Instream Flow)
• Reservoir and Carrier Operations• Policies and Agreements (Such as
Minimum Bypasses, Fish Flows, etc)• Potential Colorado River Compact
Obligations NOT Included in Phase I• Conditional Rights without Current
Demands NOT included in Phase I
21
Model OperationsModel Operations
1. Based on Natural Inflow and Return Flows from Previous Time Steps
2. Identifies Most Senior Water Right3. Estimates Diversion =min (Demand,
Water Right, Headgate Capacity, Available Flow)
4. Adjusts Downstream Flows to Reflect Senior Diversions and Immediate Return Flows
5. Future Returns are Calculated6. Repeated for Next Junior Water Right
Sequence of Results: Uncompahgre River at Delta and Gunnison River Basin
Sequence of Results: Uncompahgre River at Delta and Gunnison River Basin
Natural FlowNatural Flow
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
Uncompahgre River at Delta (09149500)2040 Average Monthly Natural Flow
Range of Model Results
Historical Average
Individual Model Results
Average Annual Natural Flow Ranges f rom 204,000 to 354,000 AF
0
10000
20000
30000
40000
50000
60000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
Uncompahgre River At Delta (09149500) 2040 Average Monthly Modeled Streamflow
Range of Model Results
Historical Average
Individual Model Results
Average Annual Modeled Streamflow Ranges from 116,900 to 246,800 AF
Modeled StreamflowModeled Streamflow
0
10000
20000
30000
40000
50000
60000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
Uncompahgre River At Delta (09149500) 2040 Average Monthly Water Available to Meet Future Demands
Range of Model Results
Historical Average
Individual Model Results
Average Annual Water Available to Meet Future Demands Ranges from 100,500 to 242,400 AF
Water AvailabilityWater Availability
Water AvailabilityWater Availability
0
50000
100000
150000
200000
250000
300000
Average 2 Driest Years 5 Driest Years 10 Driest Years
AF
/Ye
ar
Uncompahgre River At Delta (09149500) 2040 Water Available to Meet Future Demands
Range of Model Results
Historical Average
Individual Model Results
0
20000
40000
60000
80000
100000
120000
140000
160000
180000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
Gunnison River Basin-Wide 2040 Average Monthly Modeled Consumptive Use
Range of Model Results
Historical Average
Individual Model Results
Average Annual Consumptive UseRanges from 630,000 to 660,000 AF
Modeled Consumptive UseModeled Consumptive Use
50000
55000
60000
65000
70000
75000
80000
85000
90000
AF
Ridgway Reservoir 2040 Modeled Storage Content
Individual Model Results
Historical
Modeled Reservoir StorageModeled Reservoir Storage
50000
55000
60000
65000
70000
75000
80000
85000
90000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
Ridgway Reservoir 2040 Average Monthly Modeled Storage
Range of Model Results
Historical Average
Individual Model Results
Modeled Reservoir StorageModeled Reservoir Storage
Result Summary: West-Slope BasinsResult Summary: West-Slope Basins
Water AvailabilityWater Availability
0
100000
200000
300000
400000
500000
600000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
Yampa River Near Maybell (09251000) 2040 Average Monthly Water Available to Meet Future Demands
Historical Average
Hot and Wet Projection
Hot and Dry Projection
Warm and Dry Projection
Warm and Wet Projection
Median Projection
Average Annual Water Available to Meet Future Demands Ranges from 925,000 to 1,321,500 AF
0
10000
20000
30000
40000
50000
60000
70000
80000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
Yampa River Basin-Wide 2040 Average Monthly Modeled Consumptive Use
Range of Model Results
Historical Average
Individual Model Results
Average Annual Consumptive UseRanges from 269,000 to 279,000 AF
Modeled Consumptive UseModeled Consumptive Use
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
AF
YamColo Reservoir 2040 Modeled Storage Content
Individual Model Results
Historical
Modeled Reservoir StorageModeled Reservoir Storage
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
YamColo Reservoir 2040 Average Monthly Modeled Storage
Range of Model Results
Historical Average
Individual Model Results
Modeled Reservoir StorageModeled Reservoir Storage
0
5000
10000
15000
20000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
Colorado River Near Grand Lake (09011000) 2040 Average Monthly Water Available to Meet Future Demands
Historical Average
Hot and Wet Projection
Hot and Dry Projection
Warm and Dry Projection
Warm and Wet Projection
Median Projection
Average Annual Water Available to Meet Future Demands Ranges from 3,500 to 23,200 AF
Water AvailabilityWater Availability
Water AvailabilityWater Availability
0
200000
400000
600000
800000
1000000
1200000
1400000
1600000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
Colorado River Near Colorado-Utah State Line (09163500) 2040 Average Monthly Water Available to Meet Future Demands
Historical Average
Hot and Wet Projection
Hot and Dry Projection
Warm and Dry Projection
Warm and Wet Projection
Median Projection
Average Annual Water Available to Meet Future Demands Ranges from 3,052,100 to 4,986,500 AF
0
50000
100000
150000
200000
250000
300000
350000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
Colorado River Basin-Wide2040 Average Monthly Modeled Consumptive Use
Range of Model Results
Historical Average
Individual Model Results
Average Annual Consumptive UseRanges from 1,196,000 to 1,251,000 AF
Modeled Consumptive UseModeled Consumptive Use
0
5000
10000
15000
20000
25000
30000
35000
40000
AF
Vega Reservoir 2040 Modeled Storage Content
Individual Model Results
Historical
Modeled Reservoir StorageModeled Reservoir Storage
0
5000
10000
15000
20000
25000
30000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
Vega Reservoir 2040 Average Monthly Modeled Storage
Range of Model Results
Historical Average
Individual Model Results
Modeled Reservoir StorageModeled Reservoir Storage
0
100000
200000
300000
400000
500000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
Gunnison River Near Grand Junction (09152500) 2040 Average Monthly Water Available to Meet Future Demands
Historical Average
Hot and Wet Projection
Hot and Dry Projection
Warm and Dry Projection
Warm and Wet Projection
Median Projection
Average Annual Water Available to Meet Future Demands Ranges from 637,200 to 1,586,000 AF
Water AvailabilityWater Availability
0
20000
40000
60000
80000
100000
120000
140000
160000
180000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
Animas River Near Cedar Hill (09363500)2040 Average Monthly Water Available to Meet Future Demands
Range of Model Results
Historical Average
Individual Model Results
Average Annual Water Available to Meet Future Demands Ranges from 146,300 to 456,900 AF
41 PRELIMINARY RESULTS – UNDER REVIEW Colorado River Water Availability Study – Phase I
Water AvailabilityWater Availability
0
20000
40000
60000
80000
100000
120000
140000
160000
180000
200000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
San Juan River Basin-Wide 2040 Average Monthly Modeled Consumptive Use
Range of Model Results
Historical Average
Individual Model Results
Average Annual Consumptive UseRanges from 454,000 to 649,000 AF
42 PRELIMINARY RESULTS – UNDER REVIEW Colorado River Water Availability Study – Phase I
Modeled Consumptive UseModeled Consumptive Use
0
50000
100000
150000
200000
250000
300000
350000
400000
AF
McPhee Reservoir 2040 Modeled Storage Content
Individual Model Results
Historical
43 PRELIMINARY RESULTS – UNDER REVIEW Colorado River Water Availability Study – Phase I
Modeled Reservoir StorageModeled Reservoir Storage
0
50000
100000
150000
200000
250000
300000
350000
400000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
AF
Mcphee Reservoir 2040 Average Monthly Modeled Storage
Range of Model Results
Historical Average
Individual Model Results
44 PRELIMINARY RESULTS – UNDER REVIEW Colorado River Water Availability Study – Phase I
Modeled Reservoir StorageModeled Reservoir Storage
Result Summary – Natural FlowResult Summary – Natural Flow
45 PRELIMINARY RESULTS – UNDER REVIEW Colorado River Water Availability Study – Phase I
• Annual flow increases in some possible futures and decreases in others
• Annual flow generally increases in parts of the Yampa River basin and at higher elevation watersheds
• Annual flow generally decreases in southwestern watersheds and at lower elevations
• Shifts toward earlier peak runoff
• Flow decreases in late summer and early fall
Result Summary – Modeled StreamflowResult Summary – Modeled Streamflow
46 PRELIMINARY RESULTS – UNDER REVIEW Colorado River Water Availability Study – Phase I
• Annual modeled streamflow decreases basin-wide, except in the Yampa River basin, and higher elevation locations in the Upper Colorado River basin
• Modeled Flow increases in April and May and decreases in later summer and fall months
Result Summary – Water Available toMeet Future Demands
Result Summary – Water Available toMeet Future Demands
47 PRELIMINARY RESULTS – UNDER REVIEW Colorado River Water Availability Study – Phase I
• Higher elevations generally have less annual flow available to meet future demands, as a percent of modeled streamflow
• Available flow generally increases in April and May, corresponding to the shift in natural flow hydrographs
Result Summary – Modeled Consumptive UseResult Summary – Modeled Consumptive Use
48 PRELIMINARY RESULTS – UNDER REVIEW Colorado River Water Availability Study – Phase I
• Increases in Yampa, White, Upper Colorado, and Gunnison basins by 4 to 18 %
• Decreases in the San Juan and Dolores basins by 8 %
Result Summary – Use of ReservoirsResult Summary – Use of Reservoirs
49 PRELIMINARY RESULTS – UNDER REVIEW Colorado River Water Availability Study – Phase I
• Reservoirs show increased use
• Pool levels fluctuate more than historical
• Shifts in Runoff Increases the Value and Need for Storage