Section 1 Introduction ............................................................................................. 4
1.1 Purpose ..................................................................................................................... 4
1.2 Project Authority....................................................................................................... 4
1.3 Project Location ........................................................................................................ 5
1.4 Hydrologic and Hydraulic Methods .......................................................................... 5
1.5 Acknowledgment ...................................................................................................... 6
1.6 Study Results ............................................................................................................. 6
Section 2 Local Government Abstract ...................................................................... 10
2.1 Project Contact Information ................................................................................... 10
2.2 General Information ............................................................................................... 10
2.3 Survey and Mapping Information ........................................................................... 10
2.4 Hydrology ................................................................................................................ 11
2.5 Hydraulics................................................................................................................ 11
Section 3 Survey and Mapping Information.............................................................. 11
3.1 Digital Projection Information ................................................................................ 11
3.2 Field Survey Information......................................................................................... 11
3.3 Mapping .................................................................................................................. 12
Section 4 Hydrology ............................................................................................... 12
4.1 Method Description ................................................................................................ 12
4.2 Parameter Estimation ............................................................................................. 14
4.2.1 Drainage Area Boundaries ............................................................................... 14
4.2.2 Watershed Work Maps .................................................................................... 14
4.2.3 Gage Data ......................................................................................................... 14
4.2.4 Spatial Parameters ........................................................................................... 14
4.2.5 Precipitation ..................................................................................................... 14
4.2.6 Physical Parameters ......................................................................................... 14
4.3 Issues Encountered During the Study ..................................................................... 15
4.3.1 Special Problems and Solutions ....................................................................... 15
4.3.2 Modeling Warning and Error Messages .......................................................... 15
4.4 Calibration ............................................................................................................... 15
4.5 Final Results ............................................................................................................ 15
4.5.1 Hydrologic Analysis Results.......................................................................... 15
4.5.2 Verification of results ................................................................................... 16
Section 5 Hydraulics .............................................................................................. 16
5.1 Method Description ................................................................................................ 16
5.2 Work Study Maps.................................................................................................... 17
5.3 Parameter Estimation ............................................................................................. 17
5.3.1 Roughness Coefficients .................................................................................... 17
5.3.2 Expansion and Contraction Coefficients .......................................................... 17
5.4 Cross-Section Description ....................................................................................... 17
5.5 Modeling Consideration.......................................................................................... 17
5.5.1 Hydraulic Jump and Drop Analysis................................................................... 17
5.5.2. Bridges and Culverts ....................................................................................... 17
2

5.5.3 Levees and Dikes .............................................................................................. 17
5.5.4 Non-Levee Embankments ................................................................................ 18
5.5.5 Island and Flow Splits....................................................................................... 18
5.5.5 Ineffective Flow Areas...................................................................................... 18
5.6 Floodway Modeling................................................................................................. 18
5.7 Problems Encountered ........................................................................................... 18
5.7.1 Special Problems and Solutions ....................................................................... 18
5.7.2 Model Warnings and Errors ............................................................................. 18
5.8 Calibration ............................................................................................................... 18
5.9 Final Results ............................................................................................................ 18
5.9.1 Hydraulic Analysis Results................................................................................ 18
5.9.2 Verification of Results ...................................................................................... 19
Section 6 Erosion and Sediment Transport ............................................................... 19
Section 7 Draft FIS Report Data ............................................................................... 19
7.1 Summary of Discharges .......................................................................................... 19
7.2 Floodway Data ........................................................................................................ 19
7.3 Annotated Flood Insurance Rate Map .................................................................... 19
7.4 Flood Profiles .......................................................................................................... 19
List of Tables
Table 1 Methods used for a PC-Hydro analysis ................................................................ 15
Table 2 Subbasin Characteristics ...................................................................................... 15
Table 3 Summary of the Hydrologic Analysis ................................................................... 16
Table 4 Comparison of a peak discharge .......................................................................... 16
List of Figures
Figure 1.1 Watershed Map ................................................................................................. 7
Figure 1.2 Study Limits ........................................................................................................ 8
Figure 1.3 Soil Classification................................................................................................ 9
Figure 4.1 Flow Chart of Mapping Process ....................................................................... 13
Appendix A: References
Appendix B: FEMA MT-2 Forms, General Documentation and Correspondence
Appendix C: Survey Field Notes
Appendix D: Hydrologic Analysis, Supporting Documents
Appendix E: Hydraulic Analysis, Supporting Documents
Appendix F: Erosion Analysis, Supporting Documents
Exhibit
Exhibit 1 100-yr floodplain limit for the Unnamed Wash 12

3

Section 1 Introduction
1.1 Purpose
The objective of this Technical Data Notebook (TDN) is to provide 100-yr peak
discharges at Concentration Points (CPs) for the Unnamed Wash 12, 100-yr floodplain
boundary and erosion hazard information, using the most up-to-date topographic,
hydrologic, and hydraulic data.
This TDN was prepared in accordance with the “Instructions for Organizing and
Submitting Technical Documentation for Flood Studies” prepared by the Arizona
Department of Water Resources, Flood Mitigation Section (Arizona State Standard, SSA
1-97) and FEMA Guidelines. This is a local study and has not been submitted to FEMA.

1.2 Project Authority
The State of Arizona has delegated the responsibility to each county flood control
district to adopt floodplain regulations designed to promote the public health, safety
and general welfare of its citizenry as provided under the Arizona Revised Statutes
(ARS), Title 48, Chapter 21, Article 1, Sections 48-3601 through 3627. More specifically,
ARS 3609 directs county flood control districts to adopt floodplain regulations that:
A. Regulate all development of land, construction of residential, commercial or
industrial structures or uses of any kind which may divert, retard or obstruct flood
water and threaten public health or safety or the general welfare; and
B. Establish minimum flood protection elevations and flood damage prevention
requirements for uses, structures and facilities which are vulnerable to flood
damage; and
C. Comply with state and local land use plans and ordinances, if any. In
conformance with ARS 3609, the Pima County Floodplain Management Ordinance
2010 FC-5 (Ordinance) provides for protection of the public health, safety and
welfare by regulation of flood and erosion hazard areas to control these hazards
and prevent repetitive loss from floods.
D. The flood hazard areas of Pima County are subject to periodic inundation.
Erosion hazard areas of Pima County are subject to eventual lateral migration of
the low-flow channel of the watercourse. Inundation and/or lateral channel
migration may result in loss of life and property, create health and safety hazards,
disrupt commerce and governmental services, require extraordinary public
expenditures for flood protection and relief, and impair the tax base, all of which
adversely affect the public health, safety, and general welfare.
E. These flood and/or erosion losses are caused by the cumulative effect of
obstructive development in areas of special flood hazards which increase flood

4

heights, flow velocities, and cause flood and erosion damage. Uses that are
inadequately flood-proofed, elevated, or otherwise protected from flood damage,
also contribute to the flood loss.
The Ordinance, which is Title 16 of Pima County Code, describes the provisions for
floodplain regulation in Pima County.
This study has been prepared by the Pima County Regional Flood Control District (RFCD):
Pima County Regional Flood Control District
97 East Congress, Tucson, AZ 85701
The project was prepared by:
Akitsu Kimoto, Principal Hydrologist
Pima County Regional Flood Control District
97 East Congress, Tucson, AZ 85701

1.3 Project Location
The study was performed to provide drainage information for the Unnamed Wash 12.
The site includes Sections 24 and 25 of Township 13 South, Range 14 East, Pima County,
Arizona. The entire watershed of the Unnamed Wash 12 is in FEMA Zone X, as shown on
the current Flood Insurance Rate Map (FIRM) number 04019C-1713 and 1715L.
The study area for the Unnamed Wash 12 is Subbasins U12B, C and D (Fig.1.1). Since the
area downstream of River Road has been annexed to the City of Tucson and there is an
underground storm sewer located downstream of CP B (Fig. 1.1), this study used CP B as
downstream end of the study area. Detail of the underground sewer system is shown in
Highland Apartments (Co12-83-105) and River Center Development (Co12-85-111)
recorded in Docket 7787, Page 1194. The study watershed is 257 acre and was divided
into three sub-basins (Fig.1.2).

1.4 Hydrologic and Hydraulic Methods
A hydrologic analysis was performed to estimate regulatory discharge rates at CPs B, C
and D using PC-Hydro Version 5.4.2 (PC-Hydro). The parameters for PC-Hydro, such as
soil, vegetation, slope, flow path length and roughness were selected in accordance with
the PC-Hydro User Guide (Arroyo Engineering, 2007). The proposed regulatory
discharges are flow rates that have a 1-percent chance of being equaled or exceeded
each year (“100-year” discharge rates). A hydraulic analysis was performed to
determine a 100-yr floodplain boundary using HEC-GeoRAS, Version 10 (HEC-GeoRAS)
and HEC-RAS Version 4.1 (HEC-RAS).

5

1.5 Acknowledgment
This study relied on assistance from RFCD GIS staff, who were integral to the
development of the models and maps.

1.6 Study Results
The 100-yr discharges were calculated for the Unnamed Wash 12. Subbasin boundaries
and corresponding CPs are illustrated in Figure 1.2. Hydrologic characteristics for the
studied subbasins are presented in Table 2. Calculated discharges are summarized in
Table 3. The calculated discharges are compared with the USGS Regional Regression
Equation (Table 4). The comparison shows that the peak discharges calculated in this
study are reasonable.

6

Figure 1.1
Watershed Map
Unnamed 12 Wash
C EN T E

R

VILLAG

E

DR

TE

IT
RR

OR

Y

!
(

Discharge Point
Contour 10 ft.

Subbasin Name
U12 B
U12 C

Aerial : 2010 Pictometry

WI
LM

OT

RD

CRAYCROFT

U12 D

Pima County Index Map

CP C

!
(
!
( CP D
Index Map Scale 1:5,250,000

VISTA

O

VER D E

The information depicted on this display is the result
of digital analyses performed on a variety of databases
provided and maintained by several governmental agencies.
The accuracy of the information presented is limited to
the collective accuracy of these databases on the date
of the analysis. The Pima County Regional Flood Control
Department makes no claims regarding the accuracy of the
information depicted herein.
This product is subject to the Department of Transportation
Technical Services Division's Use Restriction Agreement.

RI

Pima County Regional Flood Control District

0 50 100

200

300

CP B

!
(
09/2012
\\gislib\rfcd\projects\imd\xavi\mxd\AKITSU\Unnamed_12\Unnamed_12_Wash_Fig1_1.mxd

400

500 Feet

Figure 1.2
Study Limit
Unnamed 12 Wash
C EN T E

R

VILLAG

E

DR

!
(

Discharge Points
River
Subbasins

Existing FEMA Floodplain
CRAYCROFT

ZONE A

U12 C
WI
LM

OT

RD

ZONE AE
ZONE X - SHADED
Aerial : 2010 Pictometry

U12 D
Pima County Index Map

CP C CP D

!
(
!
(

Index Map Scale 1:5,250,000

U12 B
VISTA

This product is subject to the Department of Transportation
Technical Services Division's Use Restriction Agreement.

RI

O

VER D E

The information depicted on this display is the result
of digital analyses performed on a variety of databases
provided and maintained by several governmental agencies.
The accuracy of the information presented is limited to
the collective accuracy of these databases on the date
of the analysis. The Pima County Regional Flood Control
Department makes no claims regarding the accuracy of the
information depicted herein.

Pima County Regional Flood Control District

0 50 100

200

300

400

500 Feet

Study Limit

!
(

CP B
09/2012
\\gislib\rfcd\projects\imd\xavi\mxd\AKITSU\Unnamed_12\Unnamed_12_wash_Watershed_Fig1_2.mxd

Figure 1.3
Soil Classification
Unnamed 12 Wash
C EN T E

R

VILLAG

E

DR

Subbasins

Soil Classification
Soil Group: B (82%) C (18%), PINALENOSTAGECOACH-PALOS VERDES COMPLEX,
10 TO 35 PERCENT SLOPES

CRAYCROFT

Aerial : 2010 Pictometry

WI
LM

OT

RD

U12 C

U12 D

Pima County Index Map

Index Map Scale 1:5,250,000

RI

O

VER D E

VISTA

U12 B

The information depicted on this display is the result
of digital analyses performed on a variety of databases
provided and maintained by several governmental agencies.
The accuracy of the information presented is limited to
the collective accuracy of these databases on the date
of the analysis. The Pima County Regional Flood Control
Department makes no claims regarding the accuracy of the
information depicted herein.
This product is subject to the Department of Transportation
Technical Services Division's Use Restriction Agreement.

RIVER

Pima County Regional Flood Control District

0

50 100

200

300

09/2012
\\gislib\rfcd\projects\imd\xavi\mxd\AKITSU\Unnamed_12\Unnamed_12_wash_Fig1_3.mxd

400

500 Feet

Section 2 Local Government Abstract
2.1 Project Contact Information
Contact Information:
Akitsu Kimoto
Pima County Regional Flood Control District
97 E. Congress, Tucson, AZ 85705
Akitsu.Kimoto@pima.gov
Local Technical Reviewer:
Terry Hendricks
Pima County Regional Flood Control District
97E Congress, Tucson, AZ 85705
Terry.Hendricks@pima.gov
Date Study Submitted: _________________________
Date Study Approved: __________________________
2.2 General Information
Community: Pima County Regional Flood Control
County: Pima County
River or Stream Name: Unnamed Wash 12
Reach Description: Wash in Catalina Foothills
Study Type: Hydrology and Hydraulics study of a Riverine System
Purpose of the Study: To provide regulatory discharges and map floodplain boundaries
Summary of Hydrology and Hydraulic Methods:
Brief Summary Description of the Study Results:
Acknowledgements:

2.3 Survey and Mapping Information
Digital Projection Information: NAD 1983 HARN State Plane Arizona Central
USGS Quad Sheets if available:
Mapping for Hydrologic Study: LiDAR based on 2008 flight used to derive 2-ft contour
interval maps using ArcGIS 10.0, PAG 2011 orthophotos
Mapping for Hydraulic Study: LiDAR based on 2008 flight used to derive a DEM (5-ft cell
size) for use with HEC-GeoRAS, PAG 2011 orthophotos

10

2.4 Hydrology
Model or Method Used: PC-Hydro Version 5.4.2
Storm Duration: Based on 1-hr Rainfall Depth
Hydrograph Type: NA
Frequencies Determined: 100 yr
List of Gages used in Frequency Analysis or Calibration: None
Rainfall Amounts and Reference: NOAA 14 Upper 90% Confidence Interval
Unique Conditions and Problems: None
Coordination of Q’s: Comparison with a USGS Regression Equation
2.5 Hydraulics
Model or Method Used: HEC-GeoRAS, Version 10 (HEC-GeoRAS) and HEC-RAS Version
4.1 (HEC-RAS)
Regime: Modeled as subcritical
Frequencies for which Profiles were computed: 100 yr
Method of Floodway Calculation: Floodway Not Determined in this Study
Unique Conditions and Problems: None
2.6 Erosion, Sediment Transport and Geomorphic Analysis
Summary of Method: NA
Issues Encountered During Study: NA
Summary of Findings: NA
2.7 Additional Study Information
None

Section 3 Survey and Mapping Information
3.1 Digital Projection Information
The data below are included in this TDN (see “GIS” folder)
Projection: State Plane, Arizona Central Zone
Horizontal Datum: NAD 83 HARN
Vertical Datum: NAVD 88
Units: International Feet
Aerial Photo: PAG 2011 Orthophotos
Contour: 2 feet interval
Topographic Data: 5-ft DEM
3.2 Field Survey Information
A survey was not necessary for this study.

11

3.3 Mapping
A Digital Elevation Model (DEM) derived from 2008 Light Detection and Ranging (LiDAR)
data was used for the HEC-RAS analysis. The contour interval of the topographic map is
2 feet.
Following data are included in this TDN (see “GIS” folder):
Aerial Photo: PAG 2011 Orthophotos
Contour: 2 feet interval
Topographic Data: 5-ft DEM

Section 4 Hydrology
4.1 Method Description
Hydrologic analysis was performed using PC-Hydro Version 5.4.3 (PC-Hydro). The PCHydro uses a semi-empirical method, which is similar to the Rational Formula. The
method is unique to Pima County. Pima County has been using the Pima County
Hydrology Procedures (PC-Hydro method) for over 30 years for a floodplain
management. The PC-Hydro method has been accepted by FEMA for prediction of 100yr peak discharges in Pima County (i.e. Friendly Village LOMR, Case # 08-09-0473P). The
PC-Hydro method produces conservative discharge on smaller watersheds and PC-Hydro
is the accepted method for watersheds less than one square mile in Pima County
Regional Flood Control District Technical Policy 018 (Tech-018, Appendix A). The PCHydro model requires the parameters regarding rainfall, topography, soil, and
vegetation to determine peak discharge. Those parameters were determined following
the PC-Hydro User Guide (Arroyo Engineering, 2007). The PC-Hydro output is included in
Appendix D.

12

Figure 4.1 Flow Chart of Mapping Process
Topographic Data Preparation using ArcGIS with TIN
or DEM

Hydrologic Analysis using PC-Hydro

Geometric Data Preparation using
ArcMap and HEC-GeoRAS
(stream network, stream centerlines,
cross sections, river banks, culverts,
and/or blocked obstruction)

Hydraulic Analysis using HEC-RAS
(Manually input the following data; Manning’s n-values,
culvert data, expansion and contraction coefficients,
normal depth boundary condition, ineffective flow areas,
adjustment of reach length if necessary)

Floodplain Delineation using HECGeoRAS

13

4.2 Parameter Estimation
4.2.1 Drainage Area Boundaries
The Unnamed Wash 12 watershed is located in FEMA Zone X. The downstream limit of
the study area is CP B (Fig.1.1). The study watershed is 257 acre and was divided into
three sub-basins (Fig.1.2).

4.2.2 Watershed Work Maps
A watershed work map is included in Exhibit 1. The work map includes subbasin
boundaries, concentration points, flow center lines and cross sections with station
numbers and water surface elevations. Soil group boundaries are shown for the
drainage area in Figure 1.3. Concentration points were named using the Prefix U12 for
the Unnamed Wash 12 followed by a letter assigned to each concentration point.

4.2.3 Gage Data
No gage data were used in this TDN.

4.2.4 Spatial Parameters
No spatial parameters were used in this TDN.

4.2.5 Precipitation
The NOAA 14 Atlas 90% upper confidence rainfall data was used. Rainfall depth was
selected from the NOAA 14 Upper 90% rainfall data used in PC Hydro. No area reduction
factor was applied.

4.2.6 Physical Parameters
The methods used in this study are summarized in Table 1. The PC-Hydro model
calculates runoff coefficients using an adjusted Curve Number (CN) method, which has
been developed based on the results of the USDA-ARS research. This procedure
assumes that high intensity, short duration storms result in raindrop impacts causing the
surface of soils to seal up, resulting in reducing infiltration (Caliche Effect). The CN in the
PC-Hydro model increases with increasing rainfall depth and intensity. The detail of the
method is described in PC-Hydro User Guide (Arroyo Engineering, 2007).

14

Table 1 Methods used for a PC-Hydro analysis

Rainfall Depth
Rainfall Loss
Time of Concentration

Selected Method
NOAA 14, upper 90% Confidence Interval
Adjusted SCS Curve number
Pima County Hydrology Procedure

Table 2 Watershed Characteristics
CP Name
CP B
CP C
CP D

Area
(Acre)
139
86
32

Impervious Area
(%)
13
10
10

Vegetation Cover
(%)
30
30
30

Weighted Runoff
Coefficient
0.6
0.6
0.6

4.3 Issues Encountered During the Study
4.3.1 Special Problems and Solutions
There were no problems with the hydrologic modeling.

4.3.2 Modeling Warning and Error Messages
None

4.4 Calibration
No calibration was conducted in this study.

4.5 Final Results
4.5.1 Hydrologic Analysis Results
The 100-year peak discharge at CPs B, C and D was determined using the PC-Hydro. The
result is summarized Table 3.

15

Table 3 Summary of the Hydrologic Analysis
CP Name

CP B
CP C
CP D

Location

~1300 ft north of
River Rd.
~500 ft north of
Verde Vista Dr.
~500 ft north of
Verde Vista Dr.

Area
(acre)

Time of
Rainfall
Intensity Concentration
(min)
at Tc
(in/hr)

Q100 (cfs)

139

7.12

13.3

621

86

8.15

10.0

428

32

9.74

6.1

198

4.5.2 Verification of results
The estimated peak discharge at CP A was also compared with the peak discharge
obtained from USGS Regression Equation 13 (Thomas et al., 1997) (Table 4). The
comparison showed that the PC-Hydro-derived peak discharge is 12.5% higher than the
one derived from the Regression Equation.
Table 4 Comparison of a peak discharge
CP Name
CP B
CP C
CP D

Location
~1300 ft north of River Rd.
~500 ft north of Verde Vista Dr.
~500 ft north of Verde Vista Dr.

Area (sq
mile)
0.22
0.13
0.05

Q100 PCHydro(cfs)
621
428
198

Q100
RRE
(cfs)
411
276
113

RRE: USGS Regression Equation 13

Section 5 Hydraulics
5.1 Method Description
Steady flow analysis with HEC-RAS, Version 4.1 was performed to delineate a 100-year
floodplain of the Unnamed Wash 12. Normal depth was used as a downstream
boundary condition. Parameters for the hydraulic analysis were selected following the
District Tech Policy 019.
The physical attributes of the wash were digitized in ArcGIS using the HEC-GeoRAS
extension and exported to HEC-RAS to create geospatially referenced geometric data
(cross section, reach profile). Other parameters for the steady-state analysis, such as
Manning’s n-values, expansion and contraction coefficients, boundary condition, and
ineffective flow areas were manually input into HEC-RAS. Normal-depth with a slope of
0.022 was assumed for the downstream boundary condition. The hydraulic data

16

obtained from HEC-RAS were imported into HEC-GeoRAS to delineate a floodplain
boundary for the Unnamed Wash 12.

5.2 Work Study Maps
A work study map is shown in Exhibit 1. This study mapped a floodplain upstream of CP
B.

5.3 Parameter Estimation
5.3.1 Roughness Coefficients
Manning’s n values were determined by a combination of a site visit and 2008 PAG
aerial photo. There are many reaches that are wide with several flow paths. Rather than
assign a channel and overbank Manning’s n, an average n for the whole cross-section of
0.045 was assigned.

5.3.2 Expansion and Contraction Coefficients
The expansion coefficient of 0.30 and contraction coefficient of 0.10 were used for the
entire study reach. The expansion coefficient of 0.5 and contraction coefficient of 0.3
were used for the cross sections immediately upstream or downstream of culverts.

5.4 Cross-Section Description
A 2-foot interval contour map was used to select the location of cross sections. Crosssection locations were determined primarily based on the channel topography. The
cross-section lines were drawn to be perpendicular to flow paths in HEC-GeoRAS. The
locations of cross sections and channels used for this study are shown in Exhibit 1.

5.5 Modeling Consideration
5.5.1 Hydraulic Jump and Drop Analysis
No hydraulic, drop analyses or adjustment of the floodplain was conducted in this study.

5.5.2. Bridges and Culverts
None.

5.5.3 Levees and Dikes
There are no levees or dikes located within the study limit.

17

5.5.4 Non-Levee Embankments
None.

5.5.5 Island and Flow Splits
There were no islands or flow splits modeled.

5.5.5 Ineffective Flow Areas
In general these ineffective flow areas were disconnected overbank areas that would
not convey flow to the next downstream cross-section or immediately upstream or
downstream of culverts. Contraction rate of 1:1 and expansion rate of 1:3 were used to
determine ineffective areas immediately upstream and downstream of road crossings.

5.6 Floodway Modeling
No floodway modeling was performed in this study.

5.7 Problems Encountered
5.7.1 Special Problems and Solutions
There are no special problems in the study limit.

5.7.2 Model Warnings and Errors
No errors occurred. The following warning messages occurred:
Divided flow
Energy loss greater than 1.0
Energy equation could not be balanced and defaulted to critical.
Cross-section extended vertically.
Multiple critical depths calculated.
Conveyance ratio is less than 0.7 or greater than 1.4.

5.8 Calibration
The model was not calibrated in this study.

5.9 Final Results
5.9.1 Hydraulic Analysis Results
The HEC-RAS model is included in Appendix E.
18

5.9.2 Verification of Results
The proposed floodplain limit tends to follow the existing floodplain limit. The results
suggest that the proposed floodplain limit is reasonable based on the topography.

Section 6 Erosion and Sediment Transport
No erosion or sediment transport analysis was conducted in this study.

Section 7 Draft FIS Report Data
7.1 Summary of Discharges
Peak discharges at CPs B, C and D were used for the hydraulic analysis in this study. The
estimated regulatory discharge rates are summarized in Table 3.

7.2 Floodway Data
Not applicable.

7.3 Annotated Flood Insurance Rate Map
Not applicable.

7.4 Flood Profiles
Flood profiles are included in the HEC-RAS model in Appendix E.

19

60
26

2650

50

26

26

Exhibit 1.1
Watershed Map
Unnamed 12 Wash

60

U
V
U
V
U
V
U
V
U
U
V V
V
UU
V
U
V
U
V
U
V
U
V
V
U
U
V
U
V
U
V
U
V
U
V
U
V
26 1 7

26 1

00
26

25 6 2

17 5

27
00

0
266

26
10
2576

74

2610

81

79

Aerial : 2011 Picometry Tucson
Topo: 2008 Pima Association of Governments
Datum: NAVD 1988

3

V
U

83

6

2520

Proposed 100-yr Floodplain

57

25

2570

2570

1119

0

2554
2554

262

2590

2600

2640

2580

Contours 10ft

506

46 4

V
U
90 0

7

7

25 3 6

25

34

57

69

0

U
V
V
U
V
U
V
U
1

261

2550

2680
259

V
U
V
U
U
V

24

V
U

2510

Contours 2ft

00
27

2580

2670

0

2690

267

0

68

65

2560

2650

8

25 7

25

25

7

64 3
59 9

4

47 6

10

01

14 2

25

50

25

5

14

2660

7

U
V
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V

15

25 9

25 9 5

40 0

25

9

6

25

1194

66

U
V
V
U

62

2

V
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22 8

25 3

25 3 3

25 3 2

25 2

Cross Section

2544

25 4

2533

1

0

25 3

253

39 5

V
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35 7

U
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19 5

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0

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68

25

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2

U
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CP B U
V
!
( 20 U

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2650

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25
0
53

25 2 8
2527

Discharge Point

2554

2554

747

29

2562

34

2554

950

25

9

28

80

25

2554

1008

8

68

!
(

00

2573

25 5 9

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2554

1076

54

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2630

2590

13 63

25 7 4

2555

1161

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3

76

CP C CP D
!
(!
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2556

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819

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U
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20 9

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26

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249

30

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424

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2650

2570 2580

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25

573

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5

18 5

2690

26 0

9

2582

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517

26 0

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765

U
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U
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U
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U
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86

2579

2

9

87

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89 5

0
57

25 8

25

7

944

29

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0

4

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U
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12 6

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U
V
U
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91

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26

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26 0

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U
U
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U
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U
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U
U
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U
V
U
V
U
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U
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U
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20 69

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26 2 6

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5

25

25

0

4
25

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25

2540

2570

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20

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25

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2590

Pima County Index Map
2520

25

2530

2510

2500

2510

2540

249

E RI V E

R RD

2530

25
10

0

2520

2540

20

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2530

25

25

25

20

2520

2520

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90

Index Map Scale 1:1,500,000

10

24

7
24

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0
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2460

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0
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2500

0
251

00

2490

2460

2480
80

24

24
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24

2460

2490

2470

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The information depicted on this display is the result
of digital analyses performed on a variety of databases
provided and maintained by several governmental agencies.
The accuracy of the information presented is limited to
the collective accuracy of these databases on the date
of the analysis. The Pima County Department of
Transportation Technical Services Division makes no
claims regarding the accuracy of the information depicted
herein.
This product is subject to the Department of Transportation
Technical Services Division's Disclaimer and Use Restrictions.

2490

0

5
24

2450
24

40

2440

2430

25

4

24 4

4

26
10

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15 7

10

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3

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1
26 3 0

22 51

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40

6

23 13

18 0

25

26 3

35
34

2690

N CRAYCROFT RD

24 0

26

10

2640

91

26

27

24

800

243

0

2430

400

040
24

800 Feet

Pima County Regional Flood Control
97 East Congress Street - 3rd Floor
Tucson. Arizona 85701-1207
(520)243-1800 - FAX (520)243-1821
http://www.rfcd.pima.gov

08/2012

gislib\rfcd\projects\imd\xavi\mdx\AKITSU\Unnamed_12\48x36_Unnamed_12_wash_watershed_exh1.mxd

Appendix A: References
A.1 Data collection summary.
Include a list of previous studies, other applicable studies, published and unpublished
historical
flood information, and research contacts.
A.2 Referenced documents.
Arizona Department of Water Resources, Flood Mitigation Section
“Requirements for Flood Study Technical Documentation” SS1-97, November 1997
Arroyo Engineering. 2007. PC-Hydro User Guide. Pima County Regional Flood Control
District
Eychaner, J.H., 1984. Estimation of magnitude and frequency of floods in Pima County,
Arizona, with comparisons of alternative methods: U.S. Geological Survey WaterResources Investigations Report 84-4142, 69 p.
Haan, C.T., Barfield, B.J., Hayes, J.C. 1994. Design Hydrology and Sedimentology for
Small Catchments, Academic Press.
National Weather Service. 1984. Depth-Area Ratios in the Semi-Arid Southwest
United States, NOAA Technical Memorandum NWS Hydro-40
NOAA, 2006. NOAA Atlas 14, Precipitation Frequency Atlas for the United States:
Volume 1 - Version 4.0 The Semiarid Southwest. National Weather Service,
Hydrometeorological Design Studies Center. Available on the internet at:
http://hdsc.nws.noaa.gov/ hdsc/pfds/sa/az_pfds.html
Phillips, J., and S. Tadayon. 2006. Selection of Manning’s roughness coefficient for
natural and constructed vegetated and non-vegetated channels, and vegetation
maintenance plan guidelines for vegetated channels in central Arizona: U.S. Geological
Survey Scientific Investigations Report 2006–5108, 41 p.
Thomas, B.E., H.W. Hjalmarson, and S.D. Waltemeyer. 1997. Methods for Estimating
Magnitude and Frequency of Floods in the Southwestern United States. USGS Water
Supply Paper 2433. 195 p.
U.S. Army Corps of Engineers (COE). 1998. HEC-1 Flood Hydrograph Package, Users
Manual, CPD-1A, Hydraulic Engineering Center, Davis, CA.
U.S. Army Corps of Engineers (COE). 2001. HEC-RAS, River Analysis System,
Hydraulic Reference Manual, CPD-69, Hydraulic Engineering Center, Davis, CA.

U.S. Army Corps of Engineers (COE). 2006. HEC-HMS, Hydrologic Modeling System
User’s Manual, (v. 3.1.0) CPD-74A, Hydraulic Engineering Center, Davis, CA.
U.S. Department of Agriculture Natural Resources Conservation Service (NRCS), 1986.
Urban Hydrology for Small Watersheds, Technical Release 55. Washington, DC.

Appendix B: General Documentation & Correspondence
B.1 Special Problem Reports.
B.2 Contact (telephone) reports.
Provide copies of correspondence documenting notification of the client and the methods
of addressing any special problems described in Sections 4.4.1, 5.5 and 6.5.
B.3 Meeting minutes or reports.
B.4 General Correspondence.
B.5 Contract Documents.
Provide a copy of the contract Scope of Work, not financial documents.

Appendix C: Survey Field Notes
C.1 Survey field notes for aerial mapping control.
C.2 Survey field notes for hydrologic modeling.
C.3 Survey field notes for hydraulic modeling.

Appendix D: Hydrologic Analysis Supporting
Documentation
(models, spreadsheets and supporting information is provided digitally in the TDN disk)

Appendix E: Hydraulic Analysis and As-Built Drawings
for Hydraulic Structures
(models, spreadsheets and supporting information is provided digitally in the TDN disk)

Appendix F: Erosion and Sediment Transport Analysis
Supporting Documentation
None