Analysis of the Potential Implementation of a Rapid Response High Flow

Experiment

October 15,2012

Prepared By:

S. Cl:iyton Palmer

Wayne E. Cook

Craig Ellsworth

Shane Capron

Jerry \ililhite
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

TABLE OF CONTENTS

EXECUTIVE SUMMARY ................1

INTRODUCTION: THE RAPID RESPONSE HIGH FLO\ry EXPERIMENT.....................2

Background............... .........2

Store and Release HFE ......... ...............3

Rapid Response HFE.......... .................3

PARIA RrVER FLOODS. ..................5

Frequency and Magnitude of Paria River Floods ....................6

Examples of Paria River Floods ..........7

Advance Warning of Paria River Floods ...............9

Predicting Paria River Floods ............12

RAPID RESPONSE OPERATIONS OF GLEN CANYON DAM .... 16

Normal Operations of Glen Canyon Dam ......... ....................17

Unscheduled and Emergency Operations of Glen Canyon Dam.......... .....................18

Response to the Califurnia Energlt Crisis of 2000 - 2001....... ............19

Decision Process for a Rapid Response HFE......... ...............27

Scientifically Developed Triggers .....21

Stage Changes at Lees Ferry......... .....21

Effect of Up-ramp Rates ....................22

Required Ramping Rates for a Rapid Response HFE ......... ....................23

SAFETY AND OTHER CONSIDERATIONS FOR RAPID RESPONSE........................... 25

Safety Considerations Before and After 1996 ROD Flows .....................25

The Kinematic Wave Phenomenon............. ........26

Next Steps ......26

LITERATURE CIT8D.............. ......28 ï ::lllliïl:::i:T:::::ti::_Y*T::::1:::)::::::ï,

APPENDIX B _ ACTIONS TAKEN BY WESTERN DURING THE CALIFORNIA

ENERGY CRISIS ...........29
EXECUTIVE SUMMARY

r Glen Canyon Dam is currently being

aintain beaches in Marble and Grand Canyons'

d release and rapid response HFE protocols'

ediment inputs from occasional Paria River

to accumulate in the mainstem from Paria

River inputs, then during certain windows a flood may be triggered based 9" tl" sediment retained

in the mainstem. However, because most of the sediment from the Paria River is composed of silt

and clay rather than sand, a substantial portion of the l1ual sediment input from the Paria River

would rikely be transported out of the Grand canyon before a flood is initiated under the store and

release protocol.

A rapid response

sediment. The raPid resP

occurs simultaneouslY w

respon

be dep clay has been identified as an important

consid that binds sand deposits together' making

for the

me

timelY

recreational users and property owners. ' and public notices to ensure safety for

The paria River is the single largest contributor of sand, silt, and clay to the Colorado

River 

--^- ----o - - .Large sediment input events from the Paria

River soonal storms that peak in August. Notification

of an could be obtained using a

I

comD 012) rePorted that during the

months of october and November, an indicator cfs or a flow rate increase of

at least 1,500 cfs/hr at the Kanab gage,hadaglYoprobability of resulting in a flood event of at

least 1,500 cfs at the Lees Ferry gage 7 to t hours later' The assumption is that this correlation

would hold true for the more frequent and higher intensity August

well'Uprampratesof4,000cfs/hrwouldallowpowerplantcapaciF

within in. Z io 9 hour window of notification of a Paria River floo Í'

is not an electrical emergency, past experience has shown that operations at Glen Canyon Dam

could respond sarely to äut.lá paria ^River flood event. The actions taken to meet the power

needs of the 2000-2b01 Califomia energy crisis demonstrated no fundamental safety or

operational issue with operating the darã-in a fa ihion similar to what would be required to

accommodate the rapid response HFE'
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

Prior to the first test of a rapid response HFE, a standard operating agreement would need

to be developed including agreements between Western and Reclamation, an electrical utility tied

to Western's electrical system would have to agree to take the power, and a notif,rcation protocol

would have to be developed to notify persons below the dam who might be affected by the change

in operations. This paper provides a description of the timing and magnitude of floods from the

Paria River and how high flow releases from Glen Canyon Dam could be timed to occur with

Paria River floods. This paper also describes how operations at Glen Canyon Dam have been

modif,red in the past to accommodate exceptional circumstances such as the 2000-2001 California

energy crisis and how operations could be modified in the future to accommodate a rapid response

HFE protocol.

II{TRODUCTION: THE RAPID RESPONSE HIGH FLOW EXPERIMENT

A high flow experimental (HFE) protocol for Glen Canyon Dam is currently being

implemented to improve our ability to build and maintain beaches in Marble and Grand Canyons.

In December 2011, the U.S. Bureau of Reclamation (Reclamation) released an Environmental

Assessmentt (EA) that described an experiment to test an HFE protocol spanning a lO-year period

(Reclamation20ll). The objective is to improve sediment-related resource conditions below Glen

Canyon Dam. The HFE protocol will test a number of hypotheses regarding how variations in

HFE timing, magnitude, duration, and frequency affect sandbar building and sand conservation in

Marble and Grand Canyons. Authority for modifying discharges for the environmental benefit of

Grand Canyon was provided to the Secretary of Interior with presidential approval of the Grand

Canyon Protection Act (GCPA) of 1992.

Background

Based on findings from three HFEs (see summaryby Melis 20lI), two types of HFEs were

specified in the EA (Reclamation 2011). The primary experiment was the store and release

protocol which is similar to previous high flow tests, while the rapid response protocol was also

included as a test requiring further analysis before implementation. While the timing is different,

both approaches seek to utllize sediment inputs from Paria River floods; both build on knowledge

that sediment inputs are rapidly transported downstream unless they are transported to an elevation

higher than the river's fluctuating zone; andboth approaches require a peak release of about

40,000 cubic feet per second (cfs). The EA identified the specific science question relating to the

rapid response protocol as:

Research Question #4: Is sediment conservation more effective fthan the store and

release protocol] when an HFE is held in rapid response to sediment input from the Paria

River?

t Full title: Development and Implementation of a Protocol for High-Flow Experimental Releases from Glen Canyon

Dam, Arizona,207l through 2020

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Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

The following is a short description of the two HFE approaches forld in the 2011 EA

(Reclamation 201f ;.îne pulpose of this discussion is to provide an overview of similarities and

differences between the two åpproaches. Then, we will discuss the potential benefits and

operational challenges of impiernenting a rapid response HFE and provide an analysis of how this

type of HFE maYbe imPlemented.

Sediment scientists initially assumed sediment input from tributaries to the Colorado River

below Glen canyon Dam accumuiated on the river bed over multiple years (Reclamation 1995)' It

was hypothesized that these sediment deposits could then be mobilized by a high magnitude flood

which would redistribute those sediments to the shoreline - thus creating sandbars and backwater

habitats for native f,rsh. However, this theory was dismissed by Rubin et al. (2002). Their research

indicated that the mainstem Coloraclo River does not store sand and other fine sediments as

described in the EIS (Reclamation 1995). They found that most of the sand and other fine

sediment coming into the Colorado River below

Canyon in a matter of weeks to months, depe

that in order to successfully redistribute new

occur immediately following a flood event in ord

it is transported downstream.

Store and Release HFE

protocols for fall and spring store and release HFEs are described in the EA (Reclamation

20ll). The fall sediment accounting period is fro

from Oct 1 - Nov 30. The spring sediment acco

spring HFE window is from Mar 1 - Apr 30'

would monitor the input of sand from the Pa

these two accountiniperiods, a sand budget would be created (e'g', input minus export) using a

sand routing model."Ii enough sand is pre-sent, a sand model is used to test a series of high flow

events (see Table 4 in Reclamation 2011). The flood that results in the largest magnitude and

duration flood with a positive sand massîalance in Marble canyon would be implemented during

the appropriate HFE window.

A store and release approach allows some flexibility in scheduling an HFE which allows

ample time to advise resource managers and the

Dam. This approach is most effective for sand-s

particles including silts, clays, and organic matte

ielease HFE could be implemented (Fittbin et al'

depends in part on the timing of the Paria River i

to be within a few months of a Paria River sediment input.

Rapid ResPonse HFE

Lucchitta and Leopold (1999) first considered the notion of a rapid response HFE by

proposinghigh 

r \ tal'

(2002) propose

ìmmediateiy fo rn

2}l},proposes to conduct a rapid response HF

Page 3
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

advantage of sediment inputs from the Paria River. Reclamation (20 I 1) identified the rapid

response HFE as a concept that should be tested as part of actions considered in that EA once

several issues could be resolved.

The store and release protocol utilizes suspended sand concentration measured in a

laboratory, sand budget models, and sand routing models to determine magnitude and duration of

HFEs to occur at some time in the future. The proposed rapid response protocol, on the other

hand, would require real-time measurements of flood events in the Paria River to trigger HFEs.

Currently, no means exist to obtain real-time measurements of sediment input from the Paria

River, and existing models for sediment input and transport are not calibrated to estimate retention

or transport of particle sizes f,tner than sand. Discharge could be used as a surrogate, but the

relationship between discharge and sediment input is less than ideal (Kimbrel 2012). Minimum

sediment input required to initiate an HFE would need to be established, and equipment capable of

providing real-time information on sediment input would need to be installed or models capable of

estimating sediment input would need to be developed to refine our ability to determine if this

minimum threshold was achieved. Once it is determined conditions to trigger an HFE are present,

information would need to be transmitted to dam operators in suff,rcient time so they can release

water from the dam to coincide with the flood input from the Paria River. The decision to

implement arapid response HFE must occur within amatter of hours. The success of the rapid

response approach requires coupling of Paria River floods and dam releases to deposit sediment at

an elevation above the high water mark for normal operations.

There are several potential positive effects on various resources downstream from Glen

Canyon Dam:

The potential to build and maintain ecologically important sandbar complexes with greater

efficiency than the storage and release approach for HFEs.

An advantage in delivering high suspended sediment concentrations downstream, which

has been shown to exert primary control on the building of sandbar complexes in previous

HFEs.

Matching rapid response HFE releases to a Paria River flood may require less water to be

released from the dam during the experiment.

More frequent high-flow events with more variability with respect to their magnitude,

frequency, and timing, which can potentially deliver a grealer amount of sediments to

sandbar complexes (Kimbrel 2012).

A greater storage and deposition of fine, cohesive sediments (silts and clays) along with

organic material that can help stabilize sandbars as well as enhance productivity in

backwater habitats.

There are, however, several issues that need to be addressed prior to testing of this approach,

including:

o It relies on the flow of the Paria River as the trigger for the HFE. The rapid response

decision framework requires short-term decisions that must be based on the progression of

floods in the Paria River. These floods are highly variable and of short duration, often24

hours or less.

Page 4
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

o The models used to develop and implement an HFE under the store and release protocol

are not capable of evaluating the retention of sediment and organic matter finer than sand'

These models could possibþ be developed with further refinement of the existing sand

budget model.

o prior to the initiation of a rapid response HFE, an appropriate warning system would need

to be developed. An effective *umitrg system will require coordination.with dam operators

and notices to anglers, boaters, rafteri and recreationists to ensure public safety'

o Average monthly-sand load from the Paria River is greatest in August and September'

Therefore, ur:ipíAresponse HFE would most often be triggered in these^months' which are

outside the HFE release windows outlined in the EA (March-April and octoberNovember).

o It is unclear how a large input from the Paria River during a time of low sediment storage

in the mainstem Colorado River would affect the results of a rapid response HFE' Further

understanding of ttre kinematic wave generated by a rapid response HFE is needed'

Reclamation (2011) intends to test a rapid

same release windows (March-April and October

ctober-November and March-April release

windows.

PARIA RIVER FLOODS

Before a rapid response HFE protocol can be fully developed, we must first investigate the

characteristics of paria River floods and evaluate the effectiveness of current monitoring systems'

h

The paria River has been the largest contributor of sand, silt, and clay to the Colorado

River below Glen Canyon Dam since sáiment inputs from the Little Colorado River began

declining in the ml¿-téSOs (Rubin et at.2002). rhe amount of sediment coming into the

Coloradó River when the Paria River is at flood

(Figures I artd2). Concentrations of fine

the confluence with the Colorado River, i

Page 5
Analysis of the Potential lmplementation of a Rapid Response High Flow Experiment October 15,2012

Effective management of these sporadic sediment inputs has been identihed as being critical for

maintaining the remaining beaches and other sediment-related habitat in Marble Canyon.

tr'igure 1. David Rankin, a resource specialist at the Glen Canyon National Recreation Area,

filming a flash flood and debris flow coming down the Paria River on August 19th,2012. This is

an example of the concentration of organic material the Paria River can contribute to the mainstem

Colorado River during a flood event. Photo by Heather Rankin, used with permission.

Frequency and Magnitude of Paria River Floods

The Paria River is ephemeral with occasional shorl-duration flood events. These shortduration floods may occur at anytime of the year, but occur most frequently during the monsoon

season from July to September (Figure 3). Heavy winter rainstorms or rain-on-snow events can

produce short-duration high flow events during the late winter and early spring as well. The

maximum recorded peak flow of the Paria River at Lees Ferry was estimated at 16,100 cfs in

1926. Annual peak flows at Lees Ferry from 2000 to 2010 averaged 2,486 cfs, and floods greater

than 2,500 cfs occurred at least once in 4 ofthose 1 1 years.

Paria River sediment inputs are primarily driven by summer and fall floods. Summer and

fall monsoonal storms are more likely to erode hillslopes in the upper basin than winter snowmelt

or rain-on-snow events and therefore carry more fine sediments than winter storms (Ptttbin et al.

2002). Most summer and fall floods are caused by intense thunderstorm activity in the uppermost

l4o/, of the basin (Topping 1997). Floods in the Paria River are generally high in intensity but

shorl in duration. Bankfull discharge in the Paria River is 3,178 cfs and occurs on average every

2.2 years (Topping I99l). Floods greater than bankfull discharge are rare and are generally short

Page 6
-l

Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

with a mean duration of 3.66 hours (Topping 1997). Floods along the length of Paria River are

typically conveyed with little modification or attenuation. Topping (1997) reported that for the

period of record (1923-present), flood peaks typically decreased by less than33o/o from

Cannonville to Lees Ferry and noted that some floods increased by as much as 300%o.

Figure 2. Turbid water carrying fine sediment (silts and clays) from the Paria River mixing with

clear water from the mainstem Colorado River at Lees Ferry. Note the recently deposited sand

visible in the middle of the river channel (March 2012).

Examples of Paria River Floods

Multiple floods per year can occur in the Paria River as illustrated in the 2010 hydrograph

measured at Lees Ferry (Figure 4). In 2010, there were four flood events on the Paria River

measuring over 1,000 cfs with peak flows in two of those events exceeding 2,500 cfs. The first

three flood events were the result of summer and early fall thunderstorms with the fourth

occurring in late December as a result of an extended rain or possibly a rain-on-snow event.

The first Paria River flood occurred in the hrst part of August and was the result of widespread thunderstorm activity in the drainage. A flood on August 4th peaked at2,056 cfs and was

fãllowed by a second event on August 8th that peaked at 5,618 cfs. The August 4th flow was of

short duration with the peak flow dropping to 145 cfs the following day. The August 8th event

was of longer duration with flows of 1,694 cfs being recorded on the 9th before dropping below

100 cfs otrìh. 1Qth. Neither weather station in Cedar City, UT nor in Page, AZ recorded

precipitation on August 4th. However, on August 8th 0.90" of rain was recorded in Cedar City and

Page 7
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

0.15" of rain was recorded in Page. A third flood occurred in the f,rrst part of October which

exceeded 2,300 cfs for three days, with a peak of 3,635 cfs on October 6th. From October 5th to

7th there was widespread thunderstorm activity in the area. During this time, the weather station at

Cedar City recorded a total of 1.45" of rain and the weather station in Page recorded a total of

L67" of ruin. The fourth flood occurred in late December following what was an extended rain or

possibly a rain-on-snow event. As with the October flood, peak flows in the Paria River at Lees

Ferry were elevated for three days; peaking at 1,143 cfs on December 21st. There were four days

of consistent rain in the drainage from December 20th to the 23rd. During these four days, the

weather station at Cedar City recorded a total of 1.70" of rain while the weather station in Page

recorded 0.19" of rain.

no

- 

Number of Floods

e

C' ê 150 rfl

^0

tt

o

: 4ññ lL ruu

its

o

L

o

€

E50

2

0

$' (ä .\ó Þé {g{ )ù$ )ù\ bùq dle d $ d

Date

Figure 3. Total number of floods on record in the Paria Canyon by month (http://www.

blm. gov I az I st/en /arolrsm ain/ p ar ia/ climate. html) .

Understanding the storm patterns in the Paria River drainage may improve our

understanding and ability to predict the annual discharge patterns. For example, in 2010, fall and

winter floods were of longer duration than summer floods. However, summer floods tended to be

more intense. Storms during the fall, winter, and spring typically have a wider geographic

distribution and duration, and thereby probably produce more predictable floods than isolated

summertime thunderstorrns.

Page 8
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

6000

r Parla Rlver l-{ydrograph

50m

(t,

¡¿ 4om

o

ot

q 3ooo s

(, L

o 2om

10æ

Jan Feb Mar Apr May J.ln ¡l Aug Sep Oct Nov Dec Jan

Date

Figure 4. Hydrograph for the Paria River at the Lees Ferry gage (USGS gage #09382000) in

2010 showing the daily maximum discharge.

Advance Warning of Paria River Floods

A rapid response HFE would require Glen Canyon Dam operators to time increases in

discharge so that flood waters reach the Paria/Colorado River confluence during aParia River

sediment input. To overcome the feasibility issues identif,red by Rubin et al. (2002), dam operators

would need sufficient notice of an impending flood to release water in time to have that water

arrive at the confluence with the Paria River during a flood event. Such a notihcation system could

be developed using a combination of river gages, and possibly rain gages and weather radar.

USGS has operated three river gages on the Paria River between its headwaters near

Cannonville and its confluence with the Colorado River (Figure 5). Two of these gages, the Kanab

gage and the Lees Ferry gage, are currently in operation (Figure 6). The Kanab gage (USGS gage

# 09381800) is operated by the Utah'Water Science Center in Cedar City, UT. The Kanab gage is

located a:37"06'27 " N, -1II"54'19" W at the Highway 89 crossing which is approximately 38.8

river miles upstream of the confluence with the Colorado River. The catchment above the Kanab

gage is approximately 647 mi2. The period of record for the Kanab gage is from2002 to the

present. The Lees Ferry gage (USGS gage # 09382000) is operated by the Arizona Water Science

Center in Flagstaff, AZ.The Lees Ferry gage is located at36"52'20" N, -111o35'38" W and is

approximately 1.0 river mile upstream of the confluence. The catchment above the Lees Ferry

gage is approximately 1,410 mi2. The period of record for the Lees Ferry gage is from 1923 to the

present. Discharge data for both the Kanab gage and the Lees Ferry gage are updated at 15 minute

intervals and are available on the USGS website. The equipment for the third Paria River gage

near Cannonville (USGS gage # 09381500) is still on site, but this gage has not been in operation

Page 9
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

since 2006. The Cannonville gage has been operated intermittently by the USGS since it was

established in 1950, and is the furthest upstream gage on the Paria River (located 73.3 river miles

from the Colorado River at37.480556o N, 112.260000" W). The gage has a period of record from

1950 to 1955 and 2002to2006.

Kimbrel (2012) investigated the utility of using discharge data from two USGS gages to

predict aParia River flood reaching the Colorado River at Lees Ferry. Hydraulic data from the

Kanab (upstream) and Lees Ferry (downstream) gages on the Paria River, for the period of record

where both gages were in concurrent operation, were statistically analyzed to determine if flow

parameters at the upstream gage could be used to predict flood events of specified magnitudes

withg5Yo probability at the downstream gage. Kimbrcl (2012) noted that flood events at the Lees

Ferry gage could be determined with a certain level of probability based on flows passing the

Kanab gage. Results indicated that a flood in October and November of about 2,000 cfs or arump

rate of about 1,500 cfs per hour at the Kanab gage resulted in 95%o probability that a flood event of

at least 1,500 cfs would occur I to t hours later at the Lees Ferry gage. An analysis of all floods

occurring throughout the entire year only yielded a 45o/o chance of predicting a flow of this

magnitude atthe Kanab gage reaching the Lees Ferry gage using these parameters. Floods in the

Paria River, however, typically occur from July to September (see Figure 3), which is different

than the October to November timeframe analyzed by Kimbrel (2012). One could expect that a

similar analysis of July to September floods would yield comparable results to October to

November floods with the former occurring more frequently and possibly with greater intensity.

One important consideration Kimbrel (2012) noted in using floods from the Paria River to

implement a rapid response HFE is sediment concentration, storage, and river bed evolution in the

Paria River are not perfectly correlated with discharge. While sediment concentration can be

affected by discharge, recent flow history also signihcantly influences sediment concentration. It

currently is not possible to use instantaneous flow observations in the Paria River to determine a

sediment-based trigger for a rapid response HFE since there is no means to quickly estimate the

amount of sediment a particular Paria River flood event is being transported into the mainstem

Colorado River during a flood. Analyses for sediment concentration are currently done post-flood

in a laboratory by GCMRC scientists.

Page 10
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

Figure 5. Locations of the u.s. Geological survey (usGS) stream gages and the National

WËather Service (NWS) weather stations near the Paria River'

Figure 6. The paria River g -at 

the u.s. 89 bridge crossing (left)

nü", gug" at Lees Ferry, ,iz upstream from the colorado River (right).

and the Paria

Page I I
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

Predicting Paria River Floods

Next, we consider how these stream gages could be used with National Weather Services

(NWS) weather stations to predict a Paria River flood of sufficient magnitude to consider a rapid

response HFE. The NWS maintains a network of monitoring equipment that is designed to give

advanced warning of storms that may lead to flooding in a watershed such as the Paria River.

These networks provide information that is used for everything from forecasting an increase in

monsoonal activity across the desert southwest to instantaneous rainfall data falling in a localized

area. Some of the longer range forecasts, such as tracking weather pattems that drive the monsoon,

can be extended several weeks in advance while instantaneous data can be used to estimate

magnitude, timing, and duration of impending flood events down to the sub-watershed level.

The NWS operates local weather stations at Bryce Canyon Airport near Cannonville,

Kanab Municipal Airport, and Page Municipal Airport (Figure 5). These weather stations record

hourly weather datathat include precipitation, temperature, barometric pressure, and wind

direction and speed. The NV/S also maintains a long-term weather data set for Cedar City, UT and

Page, AZ. Cedar City also provides regional weather radar, severe thunderstorm and flashflood

warnings, storm and 1-hour precipitation totals along with weather dafa on a 5-minute interval.

These data arc all available on NWS websites and could be used to evaluate the potential for a

Paria River flood event (see Appendix A).

The first warning issued by the NWS is a severe storm warning, which would apply to both

summer and winter storm events. The NWS then monitors storm total and 1-hour precipitation

totals, both of which are available online for the weather stations identif,red in Figure 5. If models

indicate that precipitation levels are sufficient to produce a flood, the NWS issues a flood or a

flash flood waming depending on the severity of the precipitation event. This would alert resource

managers of a potentialParia River flood in the immediate future. If the NWS issues a flood or a

flash flood warning, resource managers could then start monitoring weather radar, storm total, and

1-hour precipitation totals on the NWS website and the streamflow gage dafa on the USGS

website for indications of a flood in the Paria River.

A review of several recent storms shows that a flood coming from a storm centered high in

the drainage (i.e. above the Kanab gage) typically takes 6-10 hours to travel from the Kanab gage

to the Lees Ferry gage. Figure 7a illustrates a summer flood occurring on August 4,2010 on the

Paria River showing atravel time of approximately 6:45 hours between the Kanab gage (dark blue

solid line) and the Lees Ferry gage (light blue dotted line). This is within the range of the I to 9

hour time lag from when a flood is registered at the Kanab gage to when it reaches the Lees Ferry

gage reported by Kimbrel (2012).

The rate at which these floods progress downstream is likely variable depending on the

amount of water being delivered downstream with larger floods arriving downstream in a shofier

amount of time. Where the flood originates may also influence one's ability to predict its travel

time between gages. A flood originating below the Kanab gage may appear to have traveled

unusually fast downstream to the Lees Ferry gage. Figure 7b illustrates a flood with an apparcnt

travel time of approximately 4:45 hours between the Kanab and Lees Ferry gages. This could be a

situation where a portion of the flood originated below the Kanab gage and had less distance to

travel before reaching the Lees Ferry gage. Although the Kanab gage appears to be a good

Page 12
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

indicator of floods originating in the upper reaches of the basin, some floods likely originate from

below the Kanab gage and are probably only partially observable with the cuffent gaging system.

This could lead to a flood reaching the Lees Ferry gage before it was expected based on

observations at the Kanab gage alone.

In addition to identifying timing differences in floods based on where summer and fall

thunderstorms are centered, there may also be timing differences between floods generated by

thunderstorm events vs. floods generated by rain-on-snow events. Thunderstorms often create

flash floods that are high in intensity yet short in duration. Rain-on-snow events can also create

floods, but these floods are not generated as quickly and will typically last longer than floods

generated by thunderstorms. Figure 8 is an illustration of a winter flood event recorded in 2005

when the Cannonville gage was in operation. This flood took approximately 6:15 hours to travel

from the Cannonville gage (solid blue line) to the Kanab gage (dotted blue line) and

approximately l4:15 hours to go from the Kanab gage to the Lees Ferry gage (dashed blue line).

Also, note that the leading edge of all three hydrographs are not as sharp as those seen in a

summertime flash flood and that there is a decrease in peak flows at the Lees Ferry gage (the gage

furthest from the rain-on-snow event) and an attenuation in flow between upstream and

downstream sites.

Increasing the number and distribution of stream gages in the Paria River drainage could

increase the reliability and response time of using upstream flows to predict the timing and

magnitude of a flood at Lees Ferry. For example, Figure 8 shows a flood coming down the Paria

River when the Cannonville gage was in operation. The flood travel time between the Cannonville

gage and the Kanab gage appears to be approximately 6:15 hours. Incorporatingdata from the

Cannonville gagewith data from the Kanab gage could have increased the early warning of this

flood to approximately 14:15 hours before it reached Lees Ferry. However, using gages further

from Lees Ferry may also increase the probability of floods that produce a false positive trigger for

a rapid response HFE. The flood event portrayed in Figure 9, for example, shows a flood event at

the Cannonville gage where most of the input apparently occurred high in the drainage. By the

time the flood reached both the Kanab gage and the Lees Ferry gage, flows had attenuated enough

to produce what ended up being only a modest flood at Lees Ferry. This is in contrast to the flood

event portrayed in Figure 8 where the flood peak at Lees Ferry reached about 50% of the flood

peak recorded at the Cannonville and Kanab gages. Figure 10 shows a similar example of what

appears to be a false positive flood at the Kanab gage also resulting in only a modest flood at Lees

Ferry. The installation of additional gages in the Paria River basin could help reduce the

possibility of a false positive flood triggering an HFE or increase the detection probability of

floods that occur below the Kanab gage. For example, the installation of a gage on Buckskin

Wash, possibly at House Rock Valley road, may help identify floods coming from the Buckskin

'Wash drainage and into Paria River below the Kanab gage. These examples demonstrate the

importance of developing adequate triggering protocols and possibly the need for incorporaling

additional data sensing capability to the rapid response HFE protocol than solely relying on a

reading at Kanab gage to predict a flood event at Lees Ferry.

I

Page 13
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

4m0

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Figure 7. A summer flood occuring on August 4,2010 at the Kanab gage on the Paria River

(USGS gage # 09381800) with a travel time of approximarely 6:45 hours to the Lees Ferry gage

(USGS gage # 09382000) at the Colorado River (top panel, a), and a fall flood on October 5-6,

2010 with aTravel time of approximately 4:45 hours to the Lees Ferry gage (bottom panel, b).

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Page 14
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

09382000). Figure shows both flood travel time between the Cannonville gage and the Kanab gage

(4: 15 hours) utrd b.t*""tr the Kanab gage (USGS gage # 093 8 1800) and the Lees Ferry gage

itO'OO hours) and is an example of a large flood occurring high in the drainage that attenuates to

Figure 8. A winter flood occurring on the Paria River on January 10-12,2005 recorded in

..f,rr.n"" from the Cannonville gage (USGS gage# 09381500) to the Lees Ferry gage (USGS gage

+ O-q¡SZOOO). Figure shows flood travel time between the Cannonville gage and the Kanab gage

(6: I 5 hours) und b.t*..tr the Kanab gage (USGS gage # 093 8 1 800) and the Lees Ferry gage

(14:15 hours).

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Figure 9. A flood occurring on the Paria River on August 20-21, 2004 being recorded in sequence

from the Cannonville gug"lUSCS gage # 093 8 1500) to the Lees Ferry gage (USGS gage #

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Page l5
Analysis of the Potential Implementation of a Rapid Response High Flow Experimenl October 15,2012

o.sfoff

Time

Figure 10. A high intensity, short-duration flood occurring on August 16-17,2008 at the Kanab

gage on the Paria River (USGS gage # 093 8 1 800) that had attenuated to only a modest flood by the

time it reached the Lees Ferry gage (USGS gage # 09382000) at the Colorado River.

RAPID RESPONSE OPERATIONS OF GLEN CANYON DAM

Previous sections of this document addressed the practicability of predicting flood events

and presumably,large sediment inputs from the Paria River. The next step is to assess the

feasibility of manipulating Glen Canyon Dam operations to implement arapid response HFE

coincident with Paria River floods. In particular, we need to know how quickly water releases

from Glen Canyon Dam can be increased from normal operations to flood releases. While a rapid

response HFE is not an electrical emergency, the information provided below shows that

operational changes can be quickly and safely implemented at Glen Canyon Dam to respond to a

Paria River flood event.

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Page 16
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

Normal Operations of Glen Canyon Dam

Annual release targets from Glen Canyon Dam are determined by storage conditions at

Lake Powell, expected runoff, and criteria regarding water deliveries to the Lower Basin. Monthly

release targets are developed by dividing the annual release volume into monthly targets while

respecting peak-power months. These targets are adjusted as the forecast for Lake Powell inflows

are updated.

Schedules for Glen Canyon Dam releases are prepared daily by Western's Energy

Management and Marketing Office (EMMO) in Montrose, CO andare prepared one day in

advance of their operation. Scheduled Glen Canyon Dam releases are made in concert with

Reclamation's monthly release volumes determined by forecasted inflow and reservoir storage

conditions. Daily and hourly release targets are restrained by operating criteria (Table 1), as

specif,red by the 1996 Record of Decision (ROD; Department of Interior 1996) for the 1995 EIS

(Reclamation 1995).

Table 1. Glen Canyon Dam Operating Criteria.

OPERATION RELEASE

Minimum allowable release: Daytime (7am-7pm): 8,000 cfs

Nighttime (7pm-7am): 5,000 cfs

Allowable daily flow fluctuation (cfsl24h): 5,000 cfs for monthly releases <600,000 af

6,000 cfs for monthly releases between

600,000 af and 800,000 af

8,000 for monthly releases >800,000 af

Ramp rates: Upramp: 4,000 cfs/hr

Downramp: 1,500 cfs/hr

Maximum allowable release: 25,000 cfs

A release schedule for Glen Canyon Dam (and the other Salt Lake City Integrated Projects;

SLC/IP) is first prepared by Western's CRSP MC Management and Technical Services division

within the constraints of these criteria and using atarget water volume provided by Reclamation.

Western divides the monthly target into daily increments. Western, using the GT Max model,

develops an hourly schedule for the typical weekday as well as independent Saturday and Sunday

schedules for the entire month.

This schedule is provided to the EMMO division for the development of an electronic preschedule. Using the GT Max data, plus additional information, the EMMO develops the monthly

final pre-schedule and enters it into the Phoenix Supervisory Control and Data Acquisition

Page 17
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

(SCADA) system. The SCADA system is an electronic Industrial Control System (ICS); a

computer software program that monitors and controls electrical processes. Westem transfers

electrical power information for Glen Canyon Dam from its SCADA system electronically to

Reclamation's SCADA system which tracks and controls the operation of Glen Canyon Dam. The

two systems are in constant communication and monitor power system performance on a second

to second basis. Under normal operations, releases from Glen Canyon Dam are adjusted every four

seconds throughout the course of the day according to the power system regulation needs of the

grid and other factors. Instantaneous release fluctuations from Glen Canyon Dam have been

constrained to +40 megawatts (MW) and can occur without notice. Depending on the elevation of

Lake Powell, this usually equates to changes of approximately +1,000 cfs.

Unscheduled and Emergency Operations of Glen Canyon Dam

Operations at Glen Canyon Dam can be called on at a moment's notice to respond to

electrical outages and other power-related emergencies. Glen Canyon Dam is typically called on

several times a month to respond to emergency electrical situations to help maintain the integrity

of the Westem Interconnect power grid. Western and Reclamation are required to operate Glen

Canyon Dam to meet Western Electricity Coordinating Council (WECC) and North American

Electric Reliability Corporation (NERC) operating criteria by maintaining electrical reserves that

can be called on in case of an outage or emergency. Electrical reserves are generating capacity that

sit idle until a situation arises where they are needed. Electrical reserves can be activated

instantaneously and when these reserves are called on, releases from Glen Canyon Dam increase

in order to generate this additional power. Glen Canyon Dam typically carries 120 MW of reserves

which equates to about 3,000 cfs of releases in order to activate.

On occasion, Glen Canyon Dam has also been called on to generate emergency power in

excess of its reserve allocation to meet WECC and NERC obligations. Losing a major

transmission line or generating unit on the interconnecting system may cause a system emergency

by changing the frequency of the power system due to a mismatch between generators and the

load resulting in high or low voltage readings in the transmission system and lead to customer

outages. These disturbances can last up to a few hours and can result in release changes ofup to

5,000 cfs if Glen Canyon Dam is called on to help regulate the grid.

Western belongs to two reserve-sharing groups, the Rocky Mountain Reserve Group

(RMRG) and the Southwest Reserve Sharing Group (SRSG). If a reserve group member were to

have a power generation facility go down, the other reserve group members would each increase

their generation by a pre-determined amount to replace the missing generation. In the case of using

generation at Glen Canyon Dam, the CRSP MC would increase generation at the powerplant by

their proportional share of the group response. The power supplier that lost the generation has up

to t hour and 59 minutes (RMRG) or t hour (SRSG) to replace the lost generation. Glen Canyon

Dam could be called on to respond to emergencies in both Reserve Sharing Groups at the same

time.

When an emergency occurs within SRSG, information concerning the emergency is

processed by Western's Phoenix off,rce. When an emergency occurs within RMRG, information

conceming the emergency is processed by Western's Phoenix, AZ and Montrose, CO offices.

When an emergency notification is received, computer software evaluates the emergency and the

Page 18
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

Automatic Response System (ARS) terminal allocates the necessary responses to the individual

members of the RMRG and,/or SRSG units. Western's Phoenix ofhce contacts Western's Montrose

off,rce to confirm which hydropower facility will respond to the emergency. Emergency changes in

generation at Glen Canyon Dam is initiated by Western's Phoenix office in conjunction with

Reclamation and documentation for each emergency is provided by Western to Reclamation's

Control Center atPage, AZ.The 1997 Operating Agreement between Reclamation and'Western

conceming Glen Canyon Dam Operating Criteria further describes operational responses during

emergencies. These revised Operating Criteria were signed by the Secretary of the Interior on

February 24,l99l in compliance with the Grand Canyon Protection Act of 1992 (Section 1804 of

Public Law 102-575).

Response to the California Energ)¡ Crisis of 2000 - 2001

The operational response at Glen Canyon Dam to the California energy crisis of 2000-2001

demonstrated that operations at the dam can be adjusted to meet a specified need associated with

the facility. The response also demonstrated that these adjustments can occur rapidly with actions

being taken within minutes of the first notif,rcation that an operational change is needed. The

actions taken to meet the power needs of the California Independent System Operators (ISOs) also

showed there is no fundamental safety or operational issue with operating the dam in a manner

outlined above for a rapid response HFE, and that under certain circumstances, discharge patterns

outside of the 1996 ROD guidelines can be implemented to meet a warranted need associated with

the facility.

Generally, power plant operators and control area dispatchers have little or no warning that

an emergency is about to happen. However, in the example outlined below, operators and

dispatchers usually had an hour or more of notice that a problem was occurring and had more time

to take preventative actions. This example demonstrates that operational changes at Glen Canyon

Dam, similar to what is required to accommodate a rapid response HFE, have already been

successfully implemented in the past.

In the fall of 2000, the California ISOs determined that the electrical energy available in

the Southem California Area was insufficient to meet the peak needs of its customers. The

California ISOs identified that criteria established in response to a Presidential directive were met

for a Stage III power emergency, including evidence that no additional power supplies were

available. This directive mandated that federal power generation facilities, like Glen Canyon Dam,

take all possible measures to maximize power importation into Califomia under those

circumstances. Western coordinated with the Califomia ISOs to provide emergency peaking

assistance on seven occasions between September 2000 and May 2001 to maintain stability in the

power system servicing Southern California.

To obtain emergency power assistance, the ISOs were directed to first contact Westem's

CRSP office in Montrose, CO to request assistance in meeting a defined short-term energy supply

need. 'Western required that each emergency power delivery have an individual contract with a

declaration that no other power was available to meet those needs and that those needs were a true

emergency. The ISOs would notify Western that assistance may be necessary within a24-hov

period, but the timing and duration of assistance were often not specified. When the need for

additional energy became apparent, 'Western notified Reclamation to immediately begin increasing

Page 19
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

releases at Glen Canyon Dam sufficient to control the potential brown-out conditions. This service

has been offered to all electric utilities within the region under the same criteria.

An example of how releases from Glen Canyon Dam were altered to accommodate power

generation needs during the California energy crisis is illustrated in Figure 1 1. This f,rgure

illustrates how daily fluctuation and upramp rate restrictions imposed by the 1996 ROD were

suspended in order to meet porwer generation needs by showing the scheduled release (dashed line)

and the actual releases (solid line) from the dam on May 7-8,2001. Note that both power requests

were received in the late afternoon when power needs typically increase and then were canceled in

late evening when the demand for power decreased. Reclamation was allowed to increase flows

higher than the 5,000 to 8,000 cfs maximum daily fluctuation and faster than the 4,000 cfs/hr

maximum upramp rate since these emergencies were deemed Stage III electrical emergencies.

Daily fluctuations to meet emergency power generation were on occasion as high as 14,650

cfs/day and were made with upramp rates as high as 8,280 cfs/hr. Peak daily releases during

emergency releases remained below the maximum 25,000 cfs guideline, and operators at Glen

Canyon Dam followed the 1,500 cfs/hr guideline for downramping rates. A detailed day-by-day

description of the actions taken by Western to assist the California ISOs to meet the power needs

of their customers during the Califomia energy crisis of 2000-2001 can be found in Appendix B.

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Figure 11. The scheduled release (solid line) and the actual releases (dashed line) from

Glen Canyon Dam on 7-8 May 2001 to meet two Stage III power emergency requests from

the Califomia Independent System Operators.

Page 20
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

Decision Process for a Rapid Response HFE

The decision process for a rapid response HFE would need to be implemented within a

matter of hours of the flrrst indication of aParia River flood. Information indicating an increase in

dam release was being considered would need to be transmitted quickly to Westem's dispatch

center (Energy Management and Marketing Ofhce) and to operators at Glen Canyon Dam.

Prior to the hrst test of a rapid response HFE, the following would need to be developed:

o A standard operating procedure (SOP) would have to be prepared that would be followed

by Western and Reclamation operators.

o An interagency agreement between Western and Reclamation regarding the SOP referred

to above would need to be signed.

o An agreement with one or more electrical utilities to take the electrical energy produced by

arapidresponse HFE would need to be developed.

Scientifically Developed Triggers

The establishment of a clear set of scientifically based triggering criteria for the

implementation of arapid response HFE is critical to the success of the protocol. The 2002El^

(Reclamati on 2002) identified a flow of at least 2,500 cß from the Paria River is necessary to

provide the minimum sediment input to consider implementing an HFE. If this criterion had been

in place in 2010, three rapid response HFEs could have been implemented. To trigger a rapid

response HFE, additional criteria such as rate of increasing flow, magnitude of peak flow, and

duration of flood at one or more upstream gages could be used (Figure 12). Other data such as

additional streamgage data, weather radar, storm total, and 1-hour precipitation totals could also be

used to further refine HFE triggering criteria.

Stage Changes at Lees Ferry

Present operations result in daily fluctuations in river stage as more or less water is

released for power production. During normal operations, (e.g., in an 800,000 AF month such as

August), the daily stage change at Lees Ferry is about 1.9 ft. This is due to the daily fluctuation

between the nighttime flow of 8,600 cfs and the daytime flow of 16,800 cfs. The maximum rate at

which the river stage changes at Lees Ferry is approximately 1 .3 ftlhr and is limited by the current

upramp rate of 4,000 cfs/hr. The potential stage change during arapid response HFE would vary

depending on whether it is initiated during nighttime or daytime flows. For example, arapid

response HFE in August would increase the stage at Lees Ferry by 4.I ft if initiated during

nighttime flows (8,600 cfs to 31,000 cfs), but would increase by only 2.2 ft if initiated during

daytime flows (16,800 cfs to 31,000 cfs).

Page 2l
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

LaOTlme(hrrl

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Figure 12. A conceptual diagram presented by Kimbrel (2012) for screening an indicator flood

for potential rapid response HFE. Triggers identified to begin releases at Glen Canyon Dam to

match an indicator flood at the Kanab gage include reaching a minimum discharge and

exceeding a specified 1-hour ramp rate. Triggers to continue HFE releases at Glen Canyon Dam

include a resultant flood of a certain minimum discharge reaching Lees Ferry within a certain

flood window.

Effect of Up-ramp Rates

Ramping rates at Glen Canyon Dam can affect the rate of increasing or decreasing flow at

Lees Ferry and at sites utilized for recreation (Figure 13). A review of operations at Glen Canyon

Dam using awater routing model showed that flows at Lees Ferry do not appear to increase at the

same rate as at Glen Canyon Dam. For example, when the powerplant utilized upramp rates of

7,000 cfs/hr during the first week of July 1991, the maximum resultant flow increase at Lees Ferry

was only 4,500 cfs/hr. 'When 

upramp rates were increased to 10,750 cfs/hr during operations in

August 1986, the maximum resultant flow increase at Lees Ferry only increased to 4,700 cfs/hr

(USGS sage#09382000).

The CRFSS Graphical Users Interfaces (Korman et al.2004) was used to model flow

responses at Lees Ferry to ramping rates at Glen Canyon Dam ranging from 4,000 to 26,000 cfs/hr

with flows starting at a base flow of 5,000 cfs and continuing to the maximum powerplant

capacity of 31,000 cfs (Figure 13). The model indicated ramp rates from 4,000 to 9,000 cfs/hr

have a near linear, but not a 1:1 relationship with the flow rate at Lees Ferry. For ramp rates

between 9,000 and 11,000 cfs/hr, there appears to be little change in the rate of increasing flow at

Lees Ferry. In order to minimize impacts to resources below the dam while allowing maximum

flow rate increases at Lees Ferry, the CRFSS model indicated that ramp rates for a rapid response

HFE should be limited to no more than 9,000 cfs/hr.

Page 22
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

m00

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tr'igure 13. Modeled flow responses at Lees Ferry to ramping rates at Glen Canyon Dam ranging

from 4,000 to 26,000 cfs/hr. Modeled flows started at a base flow of 5,000 cfs and continuing with

the specified ramp rate to the maximum powerplant capacily of 31,000 cfs.

Required Ramping Rates for a Rapid Response HFE

The Colorado River Flow, Stage and Sediment (CRFSS) Graphical Users Interfaces

(Korman et at.2004) model was also used to determine which ramp rates would allow powerplant

capacity flows to reach Lees Ferry within the 7 to t hour window identified by Kimbrel (2012) of

an impending Paria River flood. Flows at Lees Ferry were modeled with ramp rates from Glen

Canyon Dam of 4,000; 5,000; and 6,000 cfs/hr at a dally minimum release of 8,800 cfs and a dally

maximum of 16,800 cfs. These releases were chosen to simulate a typical August release schedule

when aPariaRiver flood is most likely to occur. The typical monthly release for August under

MLFF in a minimum release year is approximately 800,000 AF and the targeted operations have

daily minimum flows of 8,800 cfs and daily maximum flows of 16,800 cfs. The model suggested

that when the release began at the daily maximum of 16,800 cfs, flows at Lees Ferry would reach

99o/o of the peak powerplant capacity flow within 7 hours at all three test ramp rates (Figure l4a).

If the release began at the daily minimum of 8,800 cfs, flows at Lees Ferry reached 88o/o,96%o and

99|o of the powerplant capacity, within 7 hours of release at Glen Canyon Dam with 4,000; 5,000

and 6,000 cfs/hr ramp rates, respectively (Figure lab). By t hours after beginning the ramp up at

Glen Canyon Dam, flows at Lees Ferry would reach 99o/o of powerplant capacity for all three

ramp rates regardless of whether the release began at the daily maximum or minimum. The rapid

response HFE proposed by Western in September 2010 suggested upramp rates of 4,000 cfs/hr as

specified in the 1996 ROD (Reclamation 1996).

Page 23
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

Þ.t (,(!

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Figure 14. Modeled flows at Lees Ferry in response to Glen Canyon Dam upramp rates of 4,000;

5,000; and 6,000 cfs/hr from a base flow of (a) 8,800 cfs and (b) 16,800 cfs to powerplant capacity

(31,000 cfs) showing powerplant capacity flows reach Lees Ferry within the 7 to t hour time

window of notification for an impendingParia River flood identified by Kimbrel (2012). These

Page 24
-_--_ll

Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

values were selected because they are the most likely daytime and nighttime minimum releases for

the month of August.

SAFETY AND OTHER CONSIDERATIONS FOR RAPID RESPONISE

A rapid response HFE would time dam releases to coincide with substantial Paria River

floods in order to utilize inputs before they are transported downstream into Lake Mead. Thus, the

decision to implement this type of HFE would have to be done quickly with established protocols

to ensure safety to recreational users, to protect private property, and to ensure that the power

system is not adversely affected. Prior to the initiation of a rapid response HFE, an appropriate

warning system would need to be developed. An effective warning system will require

coordination with dam operators and notices to anglers, boaters, rafters, and recreationists to

ensure public safety.

Safety Considerations Before and After 1996 ROD Flows

Operations before implementation of the 1996 ROD included little consideration for safety

issues for river users. Operations included unconstrained changes in flow rates that often ranged

within a day from about 1,000 cfs to near the maximum powerplant capacity of 33,000 cfs.

Generally, flow fluctuations peaked twice each day to follow electrical demand. Unrestricted

ramping rates allowed Glen Canyon Dam to follow power loads in the CRSP Power Area.

Changes in river stage at Lees Ferry initially ranged up to 5 ftlday and often exceeded 6 ftlday by

the early 1970's. In the mid-1970's, minimum flows were increased from 1,000 cß to 3,000 cfs

during the summer months (Memorial Day to Labor Day) to accommodate the National Park

Service and river running organizations. This modification to minimum flows was one of the first

accommodations to improve passage through downstream rapids that were previously impassable

at low flows.

With the implementation of the 1996 ROD, daily changes in river stage have been reduced

to less than2.5 ftlday. However, during the2000-2001 California energy crisis mentioned

previously, flow fluctuations were increased to as high as 5.8 ftlday with a peak rate of stage

change of 2.6 ftlhr. To accommodate these changes from normal operations, the downstream

recreational community in the Grand Canyon was notified by Western, Reclamation, and the

National Park Service of the higher flows and faster ramping rates. During each of the seven

periods of assistance, Reclamation's regional office was notified of pending flow changes by

Western's office in Montrose, CO. Reclamation then contacted the river users' community by

phone at the onset of each event. To the extent possible, commercial float trips in the canyon were

also notified by river guide representatives via satellite phone. The National Park Service likewise

notified people camping in Glen Canyon of the potential for impending changes in flow and stage

by dispatching a Park Service boat from Lees Ferry (Jeff English, personal communication). These

actions were deemed sufficient to satisfy downstream safety concerns resulting from these

operational changes.

Page 25
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment

The Kinematic Wave Phenomenon

October 15,2012

One concern with the implementation of either HFE protocol is the potential for creating

large kinematic waves that increase the erosion of existing sediment in the canyon. A kinematic

wave is generated by the force of gravity on the water flowing down the canyon following an

increase in flow. This is problematic because the kinematic wave travels downstream faster than

the actual water producing the flood; up to twice as fast depending on river morphology. For

example, if a rapid response HFE release from Glen Canyon Dam of 3 1,000 cfs is timed to arrive

at Lees Ferry (river mile 0) at the exact same time a flood emerges from the Paria River, a

kinematic wave will be pushed out in front of the sediment-laden flood waters as the flood

progresses downstream. This kinematic wave would reach the Little Colorado River (river mile

6L.7) approximately 7.9 hours before the arrival of sediment-laden water from the Paria River (J.

Schmitt, pers. comm.). The increase in stage and velocity associated with the kinematic wave has

the potential to increase the erosion of existing sediment in the canyon until the arrival of the

sediment-laden flood waters.

The effects of the kinematic wave could possibly be mitigated by allowing the sedimentladen flood waters from aParia River flood to travel downstream sufhciently so the wave does not

erode existing sediment in a targeted reach of the canyon without there being new sediment

present in the water column to replace it. A potential advantage of the rapid response HFE is that

its timing could be timed so the resultant kinematic wave arrives in a targeted reach of the river

shortly after the arrival of the first sediment-laden flood waters from the Paria River thereby

reducing the net loss of sediment from that reach of the river. This alternative strategy would

require further modeling to better understand how a rapid response HFE transports fine and course

sediment present in the water column and how to time an HFE to avoid a kinematic wave moving

through a critical reach of the river under clear-water conditions. Additional study of kinematic

waves is needed to better identify the impacts they have on existing sediment and whether this is

an issue that needs to be mitigated by altemative flow scenarios.

Next Steps

This paper is intended to provide information to stakeholders in the Glen Canyon Dam

Adaptive Management Group on the feasibility of conducting a rapid response HFE in concert

with a flood from the Paria River. The scope of this paper was limited to an analysis of whether

one could anticipate floods from the Paria River with reasonable certainty and determine if

operators at Glen Canyon Dam could increase releases in a timely manner to match that flood

when it reached the Colorado River. This paper also describes past changes to normal operations

at Glen Canyon Dam to accommodate such things as emergency releases and how power and

safety issues were dealt with during those situations. In summary, this paper:

Identif,res the Paria River as the single largest contributor of sand, silt, and clay to the

Colorado River below Glen Canyon Dam with large sediment input events occurring

during summer and fall monsoonal storms which peak in August;

Outlines how notification of an impending flood in the Paria River can be obtained using a

combination of upstream river gages, rain gages, and weather radar to predict a flood of a

certain magnitude reaching the Colorado River;

Page 26
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

o Identifîes that monitoring upstream river gages allows enough warning (7 to t hours) to

allow operators at Glen Canyon Dam to match powerplant capacity flows with a flood

from the Paria River at Lees Ferry using ROD upramp rates (4,000 cfs/hr); and

o Provides examples of past events that demonstrate operations at Glen Canyon Dam can

respond to a change from normal operations to something like araptd response HFE

without creating any fundamental safety or operational issues.

We recognize that there are several critical items that need to be determined or developed before a

rapid response HFE can be implemented. These include:

o A determination if additional NEPA compliance is needed to:

o Implement arapidresponse HFE outside the October-November HFE window

identified in the HFE EA,

o Identify how Reclamation will provide the tribes with a 30-day notice of an

impending HFE if its timing is dependent on a stochastic variable such as a flood in

the Paria River,

o The development of a science plan to:

o Compare the effects of a rapid response HFE with the effects of a store and release

HFE,

o Determine effects on downstream resources (i.e. humpback chub, sediment, trout,

foodbase), and

o Determine the effects of kinematic waves on downstream sediment resources and if

there is a'way to adjust the timing of the HFE release from Glen Canyon Dam to

mitigate any negative effect.

o Identify triggers (flow-based or sediment-based) that would be used to initiate an HFE

release from Glen Canyon Dam,

o Develop a real-time monitoring method for sediment inputs from the Paria River that could

be used to determine when to end an HFE,

o Develop a safety plan to notify downstream users (anglers, campers, river rutìners, science

community) of an impending HFE,

o Develop an agreement between Western and Reclamation that outlines standard operating

procedures to be followed during a rapid response HFE, and

o Identify an electrical utility tied to Western's electrical system that will agree to take the

power generated during the HFE.

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Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

LITERATURE CITED

Kimbrel, 5.2012. Determining large flood events on the Paria River for a rapid response

alternative high flow experiment. U.S. Department of the Interior, Bureau of Reclamation,

Technical Service Center Denver, Colorado. Technical Report No. SRH-2012-08. 25 pgs.

Korman, J., J. Buszowski, S. W'iele, T. Randle, T. Melis, D. Topping.2004. Colorado River Flow,

Stage and Sediment Model, Version 2.02.http.llwww.mountainsoft.net/index.html. Accessed

on2l15l12.

Lucchitta L, L.B. Leopold. 1999. Floods and sandbars in the Grand Canyon. GSA Today 9(4):l-7.

Melis, T. S., ed. 201I. Effects of three high-flow experiments on the Colorado River ecosystem

downstream from Glen Canyon Dam, Arizona: U.S. Geological Survey Circular 1366,147 p.

Reclamation. 1995. Operation of Glen Canyon Dam-Final Environmental Impact Statement,

Colorado River Storage Project, Coconino County, Arizona: Salt Lake City, Utah, Bureau of

Reclamation, Upper Colorado Regional Office, 337 p., accessed November 18,2010, at

htþ://www.usbr.gov/uclllbrarylenvdocs/eis/gclpdfs/Cov-con/cov-con.pdf.

Reclamation.1996. Final environmental assessment and finding of no signif,tcant impact, Glen

Canyon Dam beach/habitat-building test flow, spring 1996. Bureau of Reclamation, Salt Lake

City, Utah.

Reclamation.2002. Final environmental assessment and f,rnding of no significant impact,

proposed experimental releases from Glen Canyon Dam and removal of non-native fish, 2003-

2006. Bureau of Reclamation, Salt Lake City, Utah.

Reclamation. 2011. Environmental Assessment-Development and Implementation of a Protocol

for High-Flow Experimental Releases from Glen Canyon Dam, Arizona,2Ol1 through2020.

Bureau of Reclamation, Upper Colorado Region, December 30.

Rubin, D. M., D. J. Topping, J. C. Schmidt, J.HazeI, M. Kaplinski, and T. S. Melis. 2002.

Recent sediment studies refute Glen Canyon Dam hypothesis. Transactions American

Geophysical Union 83 (25):27 7 -27 8.

Topping, D.J. 1991. Physics of flow, sediment transport, hydraulic geometry and channel

geomorphic adjustment during flash floods in an ephemeral river, the Paria River, Utah and

Ãrrzona, Ph.D. thesis, 406 pp., Univ. of Wash., Seattle,'Washington.

Page 28
Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

APPENDIX A _ NATIONAL \ryEATHER SERVICE WEATHER STATION

WEBSITES

Cedar City, UT:

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&zmy:l

Bryce Canyon, UT:

I I 5.5&maxlon:1 08.5&minlat:36. 96&m

mx:1&zm]¡:1

yon+National+P ark%2 C+Utah

Page, AZ:

Kanab, UT:

APPENDIX B _ ACTIONS TAKEI{ BY WESTERN DURING THE

CALIF'ORNIA ENERGY CRISIS

The following is a day-by-day description of actions taken by'Western to assist the Califomia

ISOs to meet the power needs of their customers during the California energy crisis of 2000-2001.

September 18. 2000: Power demands in Califomia exceeded the available power supplied

by the ISOs including all requests for power outside the immediate control area. As a

result, Western increased electrical generation at Glen Canyon Dam from 325 MW to 655

MW. Releases from Glen Canyon Dam increased from 8,190 cfs to 15,780 cfs (+7,590 cfs)

over the space of one hour to meet this generation need. The magnitude of increased

generation from Glen Canyon Dam was only limited by available transmission capacity

into California. The duration of this emergency release was about four hours, after which

releases were reduced by the 1,500 cfs/hour downramp rate.

Februar)¡ 15.2001: The Glen Canyon Dam Powerplant responded to another Stage III

power emergency in California. Releases from the dam increased 5,320 cfs between 1200

and 1300 hours to meet the generation demand for the emergency. Releases of

approximately 20,000 cfs were made throughout the afternoon as emergency assistance

continued. Late in the afternoon (approximately 1900 hours), a 1,500 cfs/hr downramp was

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Analysis of the Potential Implementation of a Rapid Response High Flow Experiment October 15,2012

initiated and maintained until pre-scheduled releases of 8,500 cfs were reached in the early

morning hours of February 16,2001. The 19,950 cfs release was about 5,000 cfs above the

pre-scheduled peak release for the day and approximately 11,550 cfs above the daily

minimum.

March 19-20. 2001: The Glen Canyon Dam Powerplant increased generation by about 300

MW above its scheduled power output in response to another Stage III power emergency.

On 19 March, the response occurred at 1100 hours and lasted until 1900 hours. Releases

from Glen Canyon Dam increased 6,690 cfs between 1000 and 1200 hours and peaked at

approximately 21,000 cß between 1800 and 2000 hours. Peak flows were 7,590 cfs over

the scheduled maximum daily release of 13,500 cfs and 13,870 cfs over the daily minimum

flow. On 20 March, the response occurred at 1500 hours and lasted until 1900 hours.

Releases from Glen Canyon Dam increased 6,720 cfs between 1400 and 1500 hours and

peaked at approximately 20,000 cfs between 1800 and 2000 hours. Peak flows were 6,700

cfs over the pre-scheduled maximum daily release of 13,500 cfs and 12,130 cfs over the

daily minimum flow.

Mav 7-8. 2001: The Glen Canyon Dam Powerplant delivered 5,284 MWH into California

in response to another Stage III power emergency. Water released with this delivery totaled

approximately 11,163 AF. The maximum power delivery to California occurred on May 7

from 1600 to 1900 hours at 350 MW. Peak releases from the dam during this time were

20,830 cfs which was 8,930 cfs above the scheduled release of I 1,900 cfs. Ramping rates

between 1500 and 1600 hours were approximately 8,280 cfs/hr which was above the 4,000

cfs/hr maximum ramping specified by the 1996 ROD. The peak flow was 14,650 cfs above

the daily minimum flow which also exceed the maximum daily fluctuation rate limit of

6,000 cfs set by the 1996 ROD. The additional energy delivered was paid back by the

California ISOs by allowing for the reduction of on-peak generation at Glen Canyon Dam

by approximately 100 MW (approximately 2,400 cfs) from pre-scheduled generation

between May 14 andMay 17.

May 31.2001: The Glen Canyon Dam Powerplant responded to its last Stage III power

emergency. Generation was increased by about 135 MW above the pre-scheduled level for

the day. This response occurred at about 1400 hours with an upramping rate of 3,020 cß/hr

and continued until 1800 hours. Peak releases reached 16,050 cfs which was 3,350 cfs over

the prescheduled maximum daily release.

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