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Effects of Wildfire Effects of Wildfire in the Mountainous in the Mountainous Terrain of Southeast Terrain of Southeast Arizona Arizona Empirical Formulas to Estimate from 1-Year through 10-Year Peak Discharge from Small Post-Burn Watersheds The Hyper-Effective Drainage Area Concept… The Hyper-Effective Drainage Area Concept…

Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

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Effects of Wildfire in the Mountainous Terrain of Southeast Arizona. Empirical Formulas to Estimate from 1-Year through 10-Year Peak Discharge from Small Post-Burn Watersheds. The Hyper-Effective Drainage Area Concept…. WHY. S outheast Arizona has recently been impacted by several wildfires. - PowerPoint PPT Presentation

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Page 1: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Effects of Wildfire in the Effects of Wildfire in the Mountainous Terrain of Mountainous Terrain of

Southeast ArizonaSoutheast Arizona Empirical Formulas to Estimate from

1-Year through 10-Year Peak Discharge from Small Post-Burn

Watersheds

The Hyper-Effective Drainage Area Concept…The Hyper-Effective Drainage Area Concept…

Page 2: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

SSoutheast Arizona has recently been impacted outheast Arizona has recently been impacted by several wildfires. by several wildfires.

In the desert southwest of the United States, wildfire alters the hydrologic response of watersheds greatly increasing the magnitudes and frequency of flash floods.

The NOAA National Weather Service is tasked with the issuance of flash flood warnings to save life and property.

Tools that allow the weather forecast offices to quickly access the peak flow magnitude and flood potential from burned areas is highly desirable.

WHYWHY

Hydrologic recovery to near pre-burn conditions takes 3 to 5 yearsHydrologic recovery to near pre-burn conditions takes 3 to 5 years…

Page 3: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Southeast Arizona has recently been impacted by several wildfires.

IIn the desert southwest of the United States, n the desert southwest of the United States, wildfire alters the hydrologic response of wildfire alters the hydrologic response of watersheds greatly increasing the magnitudes and watersheds greatly increasing the magnitudes and frequency of flash floods.frequency of flash floods.

The NOAA National Weather Service is tasked with the issuance of flash flood warnings to save life and property.

Tools that allow the weather forecast offices to quickly access the peak flow magnitude and flood potential from burned areas is highly desirable.

WHYWHY

Hydrologic recovery to near pre-burn conditions takes 3 to 5 yearsHydrologic recovery to near pre-burn conditions takes 3 to 5 years…

Page 4: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Southeast Arizona has recently been impacted by several wildfires.

In the desert southwest of the United States, wildfire alters the hydrologic response of watersheds greatly increasing the magnitudes and frequency of flash floods.

TThe NOAA National Weather Service is tasked he NOAA National Weather Service is tasked with the issuance of flash flood warnings to save with the issuance of flash flood warnings to save life and property. life and property.

Tools that allow the weather forecast offices to quickly access the peak flow magnitude and flood potential from burned areas is highly desirable.

WHYWHY

Hydrologic recovery to near pre-burn conditions takes 3 to 5 yearsHydrologic recovery to near pre-burn conditions takes 3 to 5 years…

Page 5: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Southeast Arizona has recently been impacted by several wildfires.

In the desert southwest of the United States, wildfire alters the hydrologic response of watersheds greatly increasing the magnitudes and frequency of flash floods.

The NOAA National Weather Service is tasked with the issuance of flash flood warnings to save life and property.

TTools that allow the weather forecast offices to ools that allow the weather forecast offices to quickly access the peak flow magnitude and flood quickly access the peak flow magnitude and flood potential from burned areas is highly desirable.potential from burned areas is highly desirable.

WHYWHY

Hydrologic recovery to near pre-burn conditions takes 3 to 5 yearsHydrologic recovery to near pre-burn conditions takes 3 to 5 years…

Page 6: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

HOWHOW Hydrologic response within the first two

years after the occurrence of wildfire of ten ten watershedswatersheds in Southeast Arizona documented:

FFrye Canyon rye Canyon (USGS gage)(USGS gage)

DDeadman Canyon eadman Canyon (private consultant)(private consultant)

MMarijilda Canyon arijilda Canyon (USGS & NWS)(USGS & NWS)

NNoon Creek oon Creek (Schaffner & Reed)(Schaffner & Reed)

WWet Canyon et Canyon (Schaffner & Reed)(Schaffner & Reed)

UUpper Campo Bonito pper Campo Bonito (USGS)(USGS)

SSabino Creek near Mount Lemmon abino Creek near Mount Lemmon (Pima Co. gage)(Pima Co. gage)

AAlder Canyon at Ventana Windmill lder Canyon at Ventana Windmill (Schaffner & Reed)(Schaffner & Reed)

MMadera Canyon adera Canyon (Schaffner & Reed)(Schaffner & Reed)

RRomero Canyonomero Canyon (AZ Geological Survey)(AZ Geological Survey)

Indirect measurement of peak flows…Indirect measurement of peak flows…

Page 7: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Santa Catalina, Santa Rita, and Pinaleno Mountains in Southeast Arizona…Santa Catalina, Santa Rita, and Pinaleno Mountains in Southeast Arizona…

Page 8: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

DATA REQUIREMENTSDATA REQUIREMENTSSpecificationsSpecifications

short-term thunderstormshort-term thunderstorm with a duration approximately equal to or greater than the time of concentration for the burned basin at outlet

return interval of rainfall equal to or less than the 10-equal to or less than the 10-year return intervalyear return interval

storm core to have moved over at least a portion of the hyper-effective drainage areahyper-effective drainage area

documented flood was “first major flush” since watershed burned

burn occurred in mountainous terrainmountainous terrain

small total basin sizesmall total basin size (less than 15 square miles)

uncontrolled basin (no dams or other hydraulic no dams or other hydraulic structuresstructures)

Flood occurred…Flood occurred…Upper Campo BonitoUpper Campo Bonito

Page 9: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

SOUTHEAST ARIZONA POST-BURN FLOOD DATABASE FOR TEN BASINS

Prepared by Mike Schaffner and William B. Reed

Watershed Basin Average Precipitation

(inches)

Storm Duration

(hours)

GeneralStorm

Motion

Time of Concentration

(hours)

Rainfall Return Interval

λ

(t-years)

Peak Flow of Flood

y for t-year

(cfs)

Pre-Burn Peak Flow of Rainfall Return

Interval

(cfs)

Frye Creek 0.40 0.5 across 0.6 < 1-year 1400 18.5

Deadman Canyon 1.00 0.5 across 0.5 3-year 5500 67.2

Marijilda Canyon 1.25 0.7 across 0.8 5-year 8470 313

Noon Creek 0.94 0.4 across 0.4 2-year 2684 19

Wet Canyon 0.8 0.7 across 0.3 1-year 1490 7.2

Upper Campo Bonito 1.51 0.5 stationary 0.3 10-year 1900 586

Sabino Creek near Mount Lemmon

1.25 1 stationary 0.6 2-year 350 119

Alder Canyon at Ventana Windmill

1.60 1 down to up 1.2 5-year 3103 1260

Madera Canyon 0.70 0.75 stationary 0.4 < 1-year 1526 224

Romero Canyon 1.60 0.5 up to down 1.1 10-year 9500 1420

Page 10: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

SOUTHEAST ARIZONA POST-BURN FLOOD DATABASE FOR TEN BASINS

Prepared by Mike Schaffner and William B. Reed

Watershed Basin Average Precipitation

(inches)

Storm Duration

(hours)

GeneralStorm

Motion

Time of Concentration

(hours)

Rainfall Return Interval

λ

(t-years)

Peak Flow of Flood

y for t-year

(cfs)

Pre-Burn Peak Flow of Rainfall Return

Interval

(cfs)

Frye Creek 0.40 0.5 across 0.6 < 1-year 1400 18.5

Deadman Canyon 1.00 0.5 across 0.5 3-year 5500 67.2

Marijilda Canyon 1.25 0.7 across 0.8 5-year 8470 313

Noon Creek 0.94 0.4 across 0.4 2-year 2684 19

Wet Canyon 0.8 0.7 across 0.3 1-year

1490(approx 250-year flood)

7.2

Upper Campo Bonito 1.51 0.5 stationary 0.3 10-year 1900 586

Sabino Creek near Mount Lemmon

1.25 1 stationary 0.6 2-year 350 119

Alder Canyon at Ventana Windmill

1.60 1 down to up 1.2 5-year 3103 1260

Madera Canyon 0.70 0.75 stationary 0.4 < 1-year 1526 224

Romero Canyon 1.60 0.5 up to down 1.1 10-year 9500 1420

Page 11: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

ADDITIONAL SELECTED BASIN VALUESPrepared by Mike Schaffner and William B. Reed

Watershed Location Modified channelrelief ratio

β

(ft/ft)

High severity burn + Moderate severity burn

α

(%)

Average basin elevation above mean sea level

Φ

(ft/1000)

Drainage Area

ψ

(sq mi)

Frye Creek Pinaleno Mountains0.19 61 8.1 4.02

Deadman Canyon Pinaleno Mountains0.22 51 7.7 4.78

Marijilda Canyon Pinaleno Mountains0.15 59 7.1 11

Noon Creek Pinaleno Mountains0.24 77 7.7 2.99

Wet Canyon Pinaleno Mountains0.26 44 8.1 1.58

Upper Campo Bonito Santa Catalina Mountains 0.07 80 5.5 1.5

Sabino Creek near Mount Lemmon

Santa Catalina Mountains 0.07 55 8.2 3.4

Alder Canyon at Ventana Windmill

Santa Catalina Mountains 0.08 35 6.1 14

Madera Canyon Santa Rita Mountains0.22 15 7.2 4

Romero Canyon Santa Catalina Mountains 0.12 34 5.7 7.25

Page 12: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

ADDITIONAL SELECTED BASIN VALUESPrepared by Mike Schaffner and William B. Reed

Watershed Location Modified channelrelief ratio

β

(ft/ft)

High severity burn + Moderate severity burn

α

(%)

Average basin elevation above mean sea level

Φ

(ft/1000)

Drainage Area

ψ

(sq mi)

Frye Creek Pinaleno Mountains0.19 61 8.1 4.02

Deadman Canyon Pinaleno Mountains0.22 51 7.7 4.78

Marijilda Canyon Pinaleno Mountains0.15 59 7.1 11

Noon Creek Pinaleno Mountains0.24 77 7.7 2.99

Wet CanyonPinalenoMountains

0.26 44 8.1 1.58

Upper Campo Bonito Santa Catalina Mountains 0.07 80 5.5 1.5

Sabino Creek near Mount Lemmon

Santa Catalina Mountains 0.07 55 8.2 3.4

Alder Canyon at Ventana Windmill

Santa Catalina Mountains 0.08 35 6.1 14

Madera Canyon Santa Rita Mountains0.22 15 7.2 4

Romero Canyon Santa Catalina Mountains 0.12 34 5.7 7.25

Page 13: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

1) calculate the basin average precipitation for events known to have caused floods from the burned basins (an attempt was made to use the first major flush after a burn) and document storm duration,

2) determine the return period of these rain events,

3) determine the peak flow of the flood event,

4) calculate the pre-burn peak flow for the corresponding return period of the precipitation event,

5) calculate the pre-burn 5-year peak flow,

6) calculate the ratio of pre-burn peak flow to post-burn peak flowratio of pre-burn peak flow to post-burn peak flow11 and

7) multiply the pre-burn 5-year peak flow for a basin (determined in step 5) by the corresponding ratio (determined in step 6).

Steps for Calculating 5-Year Steps for Calculating 5-Year Post-Burn FlowsPost-Burn Flows

1 This ratio is calculated by dividing the result of step 3 by the result of step 4 and is basin specific…This ratio is calculated by dividing the result of step 3 by the result of step 4 and is basin specific…

Page 14: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

PRE-BURN AND POST-BURN 2-YEAR, 5-YEAR, AND 10-YEAR PEAK FLOWS

Prepared by William B. Reed

Watershed Location Pre-burn 2-year peak discharge

(cfs)

Post-burn 2-year discharge

y for 2-year

(cfs)

Pre-burn 5-year peak discharge

(cfs)

Post-burn 5-year discharge

y for 5-year

(cfs)

Pre-burn 10-year peak discharge

(cfs)

Post-burn 10-year discharge

y for 10-year

(cfs)

Frye Creek Pinaleno Mountains

26 1968 116 8778 254 19228

Deadman Canyon Pinaleno Mountains

31 2514 137 11213 300 24540

Marijilda Canyon Pinaleno Mountains

70 1897 313 8470 686 18522

Noon Creek Pinaleno Mountains

19 2685 86 12149 188 26564[1]

Wet Canyon Pinaleno Mountains

10.2 2110 45.5 9416 100 20690[2]

Upper Campo Bonito

Santa Catalina Mountains 156 499 376 1219 585 1872

Sabino Creek near Mount Lemmon

Santa Catalina Mountains 119 350 278 818 431 1293

Alder Canyon at Ventana Windmill

Santa Catalina Mountains 523 1308 1260 3103 1990 4975

Madera Canyon Santa Rita Mountains 271 1843 657 4476 1030 7017

Romero Canyon Santa Catalina Mountains

372 2492 902 6035 1420 9515

[1] Above Crippen and Bue (1977) value of 23,700.[2] Above Crippen and Bue (1977) value of 13,500.

These y values are referred to as target These y values are referred to as target values.values.

Page 15: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

PRE-BURN AND POST-BURN 2-YEAR, 5-YEAR, AND 10-YEAR PEAK FLOWS

Prepared by William B. Reed

Watershed Location Pre-burn 2-year peak discharge

(cfs)

Post-burn 2-year discharge

y for 2-year

(cfs)

Pre-burn 5-year peak discharge

(cfs)

Post-burn 5-year discharge

y for 5-year

(cfs)

Pre-burn 10-year peak discharge

(cfs)

Post-burn 10-year discharge

y for 10-year

(cfs)

Frye Creek Pinaleno Mountains

26 1968 116 8778 254 19228

Deadman Canyon Pinaleno Mountains

31 2514 137 11213 300 24540

Marijilda Canyon Pinaleno Mountains

70 1897 313 8470 686 18522

Noon Creek Pinaleno Mountains

19 2685 86 12149 188 26564[1]

Wet Canyon Pinaleno Mountains 10.2

2110(approx 500-year

flood)45.5 9416 100 20690[2]

Upper Campo Bonito

Santa Catalina Mountains 156 499 376 1219 585 1872

Sabino Creek near Mount Lemmon

Santa Catalina Mountains 119 350 278 818 431 1293

Alder Canyon at Ventana Windmill

Santa Catalina Mountains 523 1308 1260 3103 1990 4975

Madera Canyon Santa Rita Mountains 271 1843 657 4476 1030 7017

Romero Canyon Santa Catalina Mountains

372 2492 902 6035 1420 9515

[1] Above Crippen and Bue (1977) value of 23,700.[2] Above Crippen and Bue (1977) value of 13,500.

Page 16: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Basin ResponseRatio for 5-Year Events (Post-Burn vs Pre-Burn Flow)

2.5 2.9 3.26.7 6.8

27.1

75.781.8

141.3

206.9

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0

200.0

220.0

Alder Sabino Campo Bonito Romero Madera Marijilda Frye Deadman Noon Wet

Santa Catalina and Santa Rita Mountains Pinaleno Mountains

Post-Burn Response up to 207 times greater than Pre-Burn…Post-Burn Response up to 207 times greater than Pre-Burn…

Prepared by William B. Reed

Page 17: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

MULTIVATIATE RUNOFF MULTIVATIATE RUNOFF INDEXINDEX (mvi)(mvi)

Variables:

Hyper-Effective Drainage Area (determined from burn severity)

Average Basin Elevation

Objective Southeast Arizona Specific — Modified Channel Relief Ratio

Return Interval of the Forecasted Rainfall Event

Basin and storm properties chosen after several tries…Basin and storm properties chosen after several tries…

Noon CreekNoon Creek

Page 18: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

hyper-effective drainage areahyper-effective drainage area

is the area of the high severity burn plus the area of the moderate severity burn (variable in square miles)

the remaining drainage area is not used in the

calculations

therefore, the results of the post-burn envelope curve and a pre-burn equation should be

compared and the higher result used

If in doubt, compare results with standard equations…If in doubt, compare results with standard equations…

Page 19: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

modified channel relief ratiomodified channel relief ratio

is the average slope of the basin along the first order channel measured from 1,250 feet (381 meters) below

the ridge to the basin outlet --- (variable in feet/feet)

Excludes reach without channels ~ Includes reach at outlet…Excludes reach without channels ~ Includes reach at outlet…

Marijilda CanyonMarijilda Canyon

Page 20: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

The empirical equations use a multivariate runoff index defined as mvi = dcba )1000( (1)

where mvi = multivariate runoff index = high severity burn + moderate severity burn as a fraction of total watershed (square

miles/square miles); = total drainage area (square miles); = modified channel relief ratio (feet/feet); = average basin elevation above mean sea level (thousands of feet); = recurrence interval of rainfall (t-years); and

a, b, c, and d are respective exponents.

mvi = dcba )1000(

two types of equationstwo types of equations Fixed Flow Return Interval

Rainfall Return Interval a Variable and Flow Return Interval Not Assigned

mvimvi

Alpha Psi Beta Phi Lambda

Each equation has a slightly different multivariate runoff index form: multivariate runoff index for 2-year events (mvi1) =

91.156.136.0)1000( ;

multivariate runoff index for 5-year events (mvi2) =28.1254.0)1000( ;

multivariate runoff index for 10-year events (mvi3) =88.023.265.0)1000( ;

multivariate runoff index for 1 to 10 year events (mvi4) =63.07.276.156.0)1000( ;

alternative multivariate runoff index for 1 to 10 year events (mvi5) =05.122.191.149.0)1000( ;

and modified target values multivariate runoff index (mvi6) =

80.091.195.148.0)1000( .

Page 21: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Fixed Flow Return IntervalFixed Flow Return Interval

– Post-Burn 2-Year Flood (97%)*

– Post-Burn 5-Year Flood (67%)Post-Burn 5-Year Flood (67%)*

– Post-Burn 10-Year Flood (41%)*

Hydrologic recovery to near pre-burn conditions takes 3 to 5 yearsHydrologic recovery to near pre-burn conditions takes 3 to 5 years…

*Chance of one or more events in 5 yearsChance of one or more events in 5 years

Page 22: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

An Empirical 2-year Post-Burn Runoff Equation for Southeast Arizona Watersheds

y = 1011.3x0.9981

R2 = 0.9238

y = 1713.7x0.6775

0

500

1000

1500

2000

2500

3000

3500

4000

0 0.5 1 1.5 2 2.5 3 3.5

Multivariate Runoff Index

pea

k flo

w (c

fs)

Envelope Curve

Best Fit Equation

Prepared by William B. Reed

Ten data points (2-year target values)…Ten data points (2-year target values)…

Page 23: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Ten data points (5-year target values)…Ten data points (5-year target values)…

Prepared by William B. Reed

y = 4113.6x0.653

y = 1993.4x 1.0035

R2 = 0.9747

0

2000

4000

6000

8000

10000

12000

14000

16000

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5

Multivariate Runoff Index

Envelope Curve

Pea

k F

low

(cf

s)

2nd year

Best Fit Equation

R2adj = 0.96

Cross Validation Standard Error = 1757 cfsCross Validation Adjusted Correlation Coefficient = 0.90

Cross Validation R 2adj = 0.81

predictive equation: peak flow = 1993 times multivariate runoff index

An Empirical 5-Year Post-Burn Runoff Equation for Southeast Arizona Watersheds

Page 24: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

An Empirical 10-Year Post-Burn Runoff Equation for Southeast Arizona Watersheds

y = 2451.1x1.0013

R2 = 0.9711

y = 5186.3x0.7588

0

5000

10000

15000

20000

25000

30000

35000

40000

0 2 4 6 8 10 12 14

Multivariate Runoff Index

Pea

k F

low

(cf

s)

Envelope Curve

Best Fit Equation

Prepared by William B. Reed

Ten data points (10-year target values)…Ten data points (10-year target values)…

Page 25: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Fixed Flow Return IntervalFixed Flow Return IntervalConcernsConcerns

– Developed by Assuming T-Year of Developed by Assuming T-Year of Rainfall was equal to T-Year of FlowRainfall was equal to T-Year of Flow

– Same Basin Specific Ratio Used for Same Basin Specific Ratio Used for 2-Year, 5-Year, and 10-Year Flow 2-Year, 5-Year, and 10-Year Flow Return IntervalsReturn Intervals

Not bad assumptions given the properties of the data setNot bad assumptions given the properties of the data set…

Page 26: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Flow Return Interval Not Flow Return Interval Not AssignedAssigned

Rainfall Return Interval a Variable…Rainfall Return Interval a Variable…

Page 27: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Post-Burn Peak Flow

y = 5213.9x1.0002

R2 = 0.9528

y = 19083x1.038

0

5000

10000

15000

20000

25000

30000

35000

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Multivariate Runoff Index

Pea

k F

low

(cf

s)

Envelope Curve

Best Fit Equation

Prepared by William B. Reed

Ten data points where Best Fit Curve is independent of target values….Ten data points where Best Fit Curve is independent of target values….

Envelope Curve Defined to be Envelope Curve Defined to be

Above Target Values Assuming T-Above Target Values Assuming T-

Year of Flow is Equal to T-Year of Year of Flow is Equal to T-Year of

Rainfall.Rainfall.

??

Page 28: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Post-Burn Peak Flows

y = 255.08x

R2 = 0.9462

y = 471.71x0.9531

0

5000

10000

15000

20000

25000

30000

35000

40000

0 10 20 30 40 50 60 70 80 90 100

Multivariate Runoff Index

Pea

k F

low

(cf

s)

Envelope Curve

Best Fit Equation

Prepared by William B. Reed

40 data points includes 30 target values…40 data points includes 30 target values…

Looks better but is it?Looks better but is it?

This Envelope Curve is Equation 10.This Envelope Curve is Equation 10.

Page 29: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

QuestionQuestion

Duration of storm equal to or greater than time of concentration…Duration of storm equal to or greater than time of concentration…

Can T-Year Equation and Return Can T-Year Equation and Return Interval Equations be Unified?Interval Equations be Unified?

Page 30: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Paradigm ShiftParadigm Shift

– Target Values EvaluatedTarget Values Evaluated

– Results Consistent with ExpectationsResults Consistent with Expectations

– Modified Values UsedModified Values Used

Assuming t-year best fit equation is correct…Assuming t-year best fit equation is correct…

Page 31: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

tQ = post-burn runoff for the t-year return intervals between 1 and 10 years (cfs)

Modified Target Values Envelope CurveModified Target Values Envelope Curve

2-year unique target values were increased by 22%, 2-year unique target values were increased by 22%,

5-year values were unchanged,5-year values were unchanged, and and

10-year unique target values were decreased by 38%.10-year unique target values were decreased by 38%.

Preliminary ResultsPreliminary Results

(mvi6) =80.091.195.148.0)1000(

tQ 83.06 )(2983 mvi

Page 32: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Prepared by William B. Reed

34 data points includes 24 modified target values…34 data points includes 24 modified target values…

This Envelope Curve is Equation 12.This Envelope Curve is Equation 12.

Preliminary ResultsPreliminary Results

Modified Post-Burn Target Values Equations

y = 1447.9x

R2 = 0.9284

y = 2983.3x0.8306

0

5000

10000

15000

20000

25000

30000

35000

40000

0 2 4 6 8 10 12 14

Multivariate Runoff Index

Pea

k F

low

(cf

s)

Envelope Curve

Best Fit Equation

Page 33: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Comparison of Equations 10 and 12 (34 data points)

0

5000

10000

15000

20000

25000

30000

35000

40000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

Equation 10

Equation 12

Return interval increasingReturn interval increasing

Preliminary ResultsPreliminary Results

Page 34: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Ratios for Pinaleno Mountains

0

100

200

300

400

500

600

0 2 4 6 8 10 12

Return Interval

Rat

io

Deadman

Frye

Marijilda

Noon

Wet

Power (Marijilda)

Power (Frye)

Power (Deadman)

Power (Noon)

Power (Wet)

Ratios are basin specific but follow essentially the same trend.

Preliminary ResultsPreliminary Results

Page 35: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Ratios for Santa Catalina and Santa Rita Mountains

0

5

10

15

20

25

30

0 2 4 6 8 10 12

Return Interval

Rat

io

Alder

Campo Bonito

Madera

Romero

Sabino

Power (Alder)

Power (Sabino)

Power (Campo Bonito)

Power (Romero)

Power (Madera)

Ratios are basin specific but follow essentially the same trend.

Preliminary ResultsPreliminary Results

Page 36: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

ConclusionsConclusions TThe use of Hyper-Effective Drainage Area Concept has been demonstrated.he use of Hyper-Effective Drainage Area Concept has been demonstrated.

TTwo types of equations for Post-Burn Flows have been developed:wo types of equations for Post-Burn Flows have been developed:Fixed Flow Return Interval (2-Year, 5-Year, and 10-Year Equations) Rainfall Return Interval a Variable and Flow Return Interval Not Assigned.

TThese equations provide similar results.hese equations provide similar results.

Use of modified target values recommended…Use of modified target values recommended…

Page 37: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

AcknowledgmentsAcknowledgments

• Chris Smith, Dan Evans, and Saeid Tadayon of the U.S. Geological Survey

• Barry Scott of Arizona Division of Emergency Management • Robert Lefevre of U.S. Forest Service

• Ann Youberg of the Arizona Geological Survey

• Mike Schaffner, Ed Clark, Kevin Werner and Erik Pytlak of NOAA National Weather Service

Madera CanyonMadera Canyon

Page 38: Effects of Wildfire in the Mountainous Terrain of Southeast Arizona

Selected ReferencesSelected References

• Crippen, J. and C. Bue, 1977. Maximum Flood flows in the Conterminous United States. USGS Water Supply Paper 1887.

• Reed, W. and M. Schaffner, 2007. Effects of Wildfire in the Mountainous Terrain of Southeast Arizona: An Empirical Formula to Estimate 5-Year Peak Discharge from Small Post-Burn Watersheds. NOAA Technical Memorandum NWS WR-279. Available online: http://www.wrh.noaa.gov/wrh/techMemos/TM-279.pdf.

• Reed, W. and M. Schaffner, in review. Effects of Wildfire in the Mountainous Terrain of Southeast Arizona: Empirical Formulas to Estimate from 1-Year through 10-Year Peak Discharge from Small Post-Burn Watersheds.

• Schaffner, M. and W. Reed, 2005a. Effects of Wildfire in the Mountainous Terrain of Southeast Arizona: Post-Burn Hydrologic Response of Nine Watersheds. NOAA National Weather Service Western Region Technical Attachment 05-01. Available online: http://www.wrh.noaa.gov/wrh/05TAs/ta0501.pdf.

• Schaffner, M. and W. Reed, 2005b. Evaluation of Post-Burn Hydrologic Recovery of a Small Mountainous Watershed: Upper Campo Bonito Wash in Southern Arizona. NOAA National Weather Service Western Region Technical Attachment 05-06. Available online: http://www.wrh.noaa.gov/wrh/05TAs/ta0506.pdf.

• Thomas, B., et. al., 1997. Methods for Estimating Magnitude and Frequency of Floods in the Southwestern United States. USGS Water-Supply Paper 2433. Available online: http://pubs.er.usgs.gov/pubs/wsp/wsp2433#viewdoc.

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Basin Conditions

River Forecasts

Water Supply

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