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Glen Canyon Dam Technical Work Group 

Agenda Item Information 

October 29, 2014

Agenda Item 

Update ̶ Colorado River Annual Operating Plan and Drought Contingency Planning 

Presenter 

Katrina Grantz, Hydraulic Engineer, Bureau of Reclamation, Upper Colorado Region 

Previous Action Taken 

N/A 

Relevant Science 

N/A 

Background Information 

The presentation is intended to provide information to TWG members on the Colorado River 2015 

Annual Operating Plan (AOP) and Reclamation’s drought contingency planning activities in the 

Upper Colorado River Basin. 

The Annual Operation Plan (AOP) for the Colorado River reports on both the past operations of 

the Colorado River Reservoir for the completed year as well as projected operations and releases 

from these reservoirs for the current (i.e., upcoming year). The purpose of the AOP is to illustrate 

the potential range of reservoir operations that might be expected in the upcoming water year and 

reflects operational rules, guidelines and decisions that have been put into place for the Colorado 

River reservoirs, including the 2007 Interim Guidelines. The AOP document is prepared by 

Reclamation, in consultation with representatives of the Governors of the seven Colorado River 

Basin States, Indian Tribes, Upper Colorado River Commission, appropriate Federal agencies, and 

others interested in Colorado River operations. Further Information and a draft version of the 2015 

AOP can be found at: http://www.usbr.gov/uc/water/rsvrs/ops/aop/index.html. 

Entities that rely on the Colorado River are concerned with the ongoing drought, declining 

reservoirs, the potential for loss of hydroelectric generation at Lake Powell, and the potential for the 

first ever shortages in the Lower Basin. In the Colorado River Basin (Basin), 2000 to 2014 was the 

driest 15–year period in over 100 years of record keeping. During that time, water storage in the 

major reservoirs in the Basin declined from nearly full to about half of capacity. Within the Upper 

Basin, if current drought conditions persist, recent analyses show a small chance that Lake Powell 

water elevations could be low enough within the next decade that Glen Canyon Dam could lose the 

ability to generate power, which could result in the loss of funding operations for Colorado River 

Storage Project (CRSP) reservoirs and significant environmental programs in the Upper Basin and in 

the Grand Canyon and could upset the stability and reliability of power supplies on the Western 

Grid. Confronted with these possibilities, Reclamation has been working with Basin stakeholders to 

establish potential contingency options that are consistent with the Law of the River and other 

existing laws. Elements of these contingency options include: (1) expanding weather modification to 

increase supplies for the Colorado River system; (2) coordination of CRSP reservoir operations to 

better maintain power pool at Glen Canyon Dam; and (3) Upper Basin demand management to 

allow more water to reach Lake Powell. 
2015 Colorado River Annu

Operating Plan 

Drought Contingency Plann

Technical Work Group Meeting

October 29, 2014
Update: Colorado River 

Annual Operating Plan

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Colorado River Annual Operatin

• Report of Colorado River hydrology and reservoir 

for past year and projections for the upcoming yea

• Purpose: Illustrate range of reservoir operations th

be expected in the upcoming water year 

• Reflects operational rules, guidelines and decision

have been put into place for the Colorado River re

• AOP document is prepared by Reclamation, in co

with representatives of the Basin States, Indian TrUpper Colorado River Commission, appropriate Fagencies, and other Basin stakeholders. Typically consultation meetings.

• 2015 AOP currently in final stages of developmen

transmittal to Secretary of Interior in upcoming wehttp://www.usbr.gov/uc/water/rsvrs/ops/aop/index.

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Reservoir Operations

Water Years 2014 and 201
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http://www.usbr.gov/uc/water/notice/Graphs/Upper_Colorado.html

Snowpack peaked at 111%

on April 8, 2014

Upper Basin Hydrology
Basin Storage

As of 

10/21/2014

51%

65%

71%

88%

91%

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Reservoir

WY 201

Inflow 

(KAF)

Fontenelle 1,424 

Flaming Gorge 1,689 

Blue Mesa 1,145 

Navajo 696 

Powell 10,381 

Water Year 2

Observed Unregula

Upper Basin Storage

1 1981-2010 period

http://www.usbr.gov/uc/water/basin/tc_cr.html
1,219.6 

Lake Powell Lake Mead 3,700 24.322 maf

Not to Scale

9.5 maf 

17.0 maf

1,1451,075

3,6483,575

2.5 

maf

1.9 

maf Dead Storage Dead Storage

0.0 maf 895 3,370 0.0 maf

1,105 

5.9 maf 3,525 1,025 6.0 

1,081.33 feet

10.1 maf in storage

39% of capacity

3,605.53 feet

12.3 maf in storage

51% of capacity

End of Water Year 2014 Conditio

7.48 maf

Observed Unregulated Inflow into Powell1 = 10.38 maf (96% of 

1 Percent of average inflow is based on the 30-year period 

of record from 1981-2010 . 7
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Observed Water Year 2014: 10.38 maf (96%)
Lake Powell Operational Tier 

Determinations (2007 Interim Guide

• August 24-Month Study projection of January 1 e

establishes the Lake Powell operating Tiers for thupcoming year

• If in Upper Elevation Balancing, April 24-Month S

projection of Sept 30th elevation / storage could s

Powell operations to balancing or equalization foremainder of water year

• Reservoir operating plans are continually update

throughout the water year as hydrologic and opeconditions change.

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Lake Powell & Lake Mead Operational Ta

Operational Tiers for Water/Calendar Year 2015 determined with the August 2014 

10

3,596.62 ft

Jan 1,2015 

projection 

J
Lake Powell Operational Scenarios

Based on October 2014 24-Month Study Inflow Scenarios

Powell Inflow 

Scenario

WY 2015

Release Projection

Probable 

Minimum

Upper Elevation Balancing Tier 

w/ Projected April shift to Balancing

9.0 maf release

Most 

Probable

Upper Elevation Balancing Tier 

w/ Projected April shift to Balancing

9.0 maf release

Probable 

Maximum

Upper Elevation Balancing Tier 

w/ Projected April shift to Equalization

12.1 maf release

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Powell release = 8.23 maf 

PowellSep30 < 3,575 ft

Release controlled by balancing 

contents up to 9.0 maf 

MeadSep30 <= 1,075 ft and 

PowellSep30 >= 3,575 ft

Release controlled by 

2015 Equalization Level 

of 3,649 ft - 20 ft (3,629)

(Mead below 1,105 ft) 

Release controlled by 

MeadSep30 elevation at 1105 

PowellSep30 elevation between 

3,629 ft and 3,649 ft. 

Relea

Powel

equalizat

Res

to p
Reclamation 

Upper Basin Drought Contingency Planning
Colorado River Drought

• Inflow into Lake Powell has been below averag

the past 15 years (2000-2014) 

• The period from 2000-2014 was the driest 15-y

period in over 100 years of historical record

• Tree-ring reconstructions show more severe d

have occurred over the past 1200 years (e.g., in the mid 1100s)

• However, based on the paleo-record, less than 

year periods were drier than the period from 22014

• Not unusual to have a few years of above ave

inflow during longer-term droughts (e.g., 1950s

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State of the System (Water Years 1999-201

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Percent of Traces with Event or System Conditio

Results from October 2014 CRSS1,2,3 (values in percent)

Event or System Condition 2015 2016 201

Upper

Basin –

Lake 

Powell

Equalization Tier 8 23 25 

Equalization – annual release > 8.23 maf 8 23 25 Equalization – annual release = 8.23 maf 0 0 0

Upper Elevation Balancing Tier (Powell < Eq level and ≥ 3,575 ft) 92 59 55 

Upper Elevation Balancing – annual release > 8.23 maf 49 47 43 

Upper Elevation Balancing – annual release = 8.23 maf 43 10 11 

Upper Elevation Balancing – annual release < 8.23 maf 0 2 1

Mid-Elevation Release Tier (Powell < 3,575 and ≥ 3,525 ft) 0 18 18 

Mid-Elevation Release – annual release = 8.23 maf 0 0 0

Mid-Elevation Release – annual release = 7.48 maf 0 18 18 

Lower Elevation Balancing Tier (Powell ≤ 3,525 ft) 0 0 2Powell below Minimum Power Pool (Powell ≤ 3,490 ft) 0 0 0

Lower

Basin –

Lake 

Mead

Shortage Condition – any amount (Mead 

≤ 1,075 ft) 0 25 53 

Shortage – 1st level (Mead 

≤ 1,075 and 

≥ 1,050) 0 25 40 

Shortage – 2nd level (Mead < 1,050 and 

≥ 1,025) 0 0 13 

Shortage – 3rd level (Mead < 1,025) 0 0 0 

Surplus Condition – any amount (Mead 

≥ 1,145 ft) 0 0 6 

Surplus – Flood Control 0 0 0

Normal or ICS Surplus Condition 100 75 41 

1 Reservoir initial conditions based on the most probable October 24-month Study projected levels for December 31, 2014.2 Hydrologic inflow traces based on resampling of the observed natural flow 

record from 1906-2010.

3 Percentages shown may not be representative of the full range of future 16 possibilities that could occur with different modeling assumptions.
Upper Basin Drought Planning

• Concern regarding ongoing drought, decli

reservoirs and the possibility of loss of hydroelectric generation at Lake Powell

• Reclamation working with Upper Basin Sta

other stakeholders to develop an Upper BContingency Plan 

• A primary objective in the Upper Basin is t

preserve power production at Glen Canyo

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UB Drought Contingency Plann

• Ongoing coordination with Colorado Riv

stakeholders

• Upper Basin planning considerations

1. Weather modification (cloud seeding)2. Upper Basin voluntary demand manageme3. Upper Basin Reservoirs extended operatio

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Extended Reservoir Operations

• An extension of the operation of the CRS

reservoirs above Lake Powell to release into Lake Powell during critically low per

• Stay within existing RODs and BOs• Evaluating taking “action” (moving water 

UB reservoirs) when Powell is forecastebelow critical elevation thresholds

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Reclamation Drought Contingen

Modeling Approach

• Evaluating CRSP Extended Operations wh

Powell forecasted to be below 3,525’ 

– Also evaluated 3,490’ in previous model runs; 

results indicate that could be too late for action

• Evaluating demand management scenario

Upper and Lower Basins

• Testing operational implementation strateg

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Reclamation modeling prelimina

results

• Reclamation modeling to date has produced very 

results to Basin States’ previous modeling results

• Extended Operations of CRSP reservoirs can sig

reduce risk of Powell dropping below minimum p

• Additional efforts (demand management in Uppe

Lower basin) may further improve ability to improconditions at Lake Powell

• Additional modeling is necessary 

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Summary

• Fortunate to start the drought in 2000 wit

full system conditions

• A wide range of future outcomes is possi

through 2020, including an “extended dro

• Putting water back into the system, throu

range of options, improves system resiliehelps to avoid critical reservoir elevations

• It is important to develop a Upper Basin 

Contingency Plan for the small, but real, possibility of reaching critical elevations aPowell
Questions?

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