Section 1 Introduction ..................................................................... 3
1.1 Purpose...................................................................................................................... 3
1.2 Project Authority....................................................................................................... 3
1.3 Project Location ........................................................................................................ 4
1.4 Hydrologic and Hydraulic Methods.......................................................................... 4
1.5 Acknowledgments..................................................................................................... 5
1.6 Study Results ............................................................................................................ 5

Section 2 FEMA Forms .................................................................... 9
2.1 Study Documentation Abstract for FEMA submittals.............................................. 9
2.1.1 Date Study Accepted.......................................................................................... 9
2.1.2 Study Contractor ................................................................................................ 9
2.1.3 Local Technical Reviewer ................................................................................. 9
2.1.4 Reach Description.............................................................................................. 9
2.1.5 USGS Quad Sheets ............................................................................................ 9
2.1.6 Unique Conditions and Problems ...................................................................... 9
2.1.7 Coordination of Peak Discharges..................................................................... 10
2.2 FEMA Forms .......................................................................................................... 10

Section 3 Survey and Mapping Information................................. 10
3.1 Field Survey Information........................................................................................ 10
3.2 Mapping .................................................................................................................. 10

Section 4 Hydrology....................................................................... 10
4.1 Method Description ................................................................................................ 10
4.2 Parameter Estimation .............................................................................................. 11
4.2.1 Drainage Area .................................................................................................. 11
4.2.2 Watershed Work Map ...................................................................................... 11
4.2.3 Gage Data......................................................................................................... 11
4.2.4 Statistical Parameters ....................................................................................... 11
4.2.5 Precipitation ..................................................................................................... 11
4.2.6 Physical Parameters ......................................................................................... 12
4.3 Problems Encountered During the Study................................................................ 14
4.3.1 Special Problems and Solutions....................................................................... 14
4.3.2 Modeling Warning and Error Messages .......................................................... 14
4.4 Calibration............................................................................................................... 14
4.5 Final Results........................................................................................................ 14
4.5.1 Hydrologic Analysis Results........................................................................ 14
4.5.2 Verification results....................................................................................... 15

Section 5 Hydraulics ...................................................................... 16
5.1 Method Description ................................................................................................ 16
5.2 Work Study Maps ................................................................................................... 17
5.3 Parameter Estimation .............................................................................................. 18
5.3.1 Roughness Coefficients ................................................................................... 18
5.3.2 Expansion and Contraction Coefficients ......................................................... 18
5.4 Cross-Section Description ...................................................................................... 18
5.5 Modeling Consideration.......................................................................................... 18
5.5.1 Hydraulic Jump and Drop Analysis................................................................. 18
1

5.5.2. Bridges and Culverts....................................................................................... 18
5.5.3 Levees and Dikes ............................................................................................. 18
5.5.4 Island and Flow Splits...................................................................................... 19
5.5.5 Ineffective Flow Areas..................................................................................... 19
5.6 Floodway Modeling ................................................................................................ 19
5.7 Problems Encountered ............................................................................................ 19
5.7.1 Special Problems and Solutions....................................................................... 19
5.7.2 Model Warnings and Errors............................................................................. 19
5.8 Calibration............................................................................................................... 20
5.9 Final Results............................................................................................................ 20
5.9.1 Hydraulic Analysis Results.............................................................................. 20
5.9.2 Verification of Results ..................................................................................... 20

Section 6 Erosion and Sediment Transport................................. 21
Section 7 Draft FIS Report Data .................................................... 21
7.1 Summary of Discharges.......................................................................................... 21
7.2 Floodway Data ........................................................................................................ 21
7.3 Annotated Flood Insurance Rate Map .................................................................... 21
7.4 Flood Profiles.......................................................................................................... 21
Appendix A: References
Appendix B: 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 1
Exhibit 2
Attached CD
Casas Adobes TDN with supporting models and GIS data.
List of Tables
Table 4.1 Methods used for a HEC-HMS analysis
Table 4.2. Physical Parameters for Sub-Basins
Table 4.3. Physical Parameters for Reaches
Table 4.4 Summary of sub-basin discharges.
Table 4.5. Summary of 100-yr Peak Discharge Values
Table 4.8. Comparison of peak discharge with regional regression equations.
Table 7. Summary of Discharges
List of Figures
Figure 1.1 Casas Adobes Wash Watershed Map
Figure 1.2 Study Limit of the Casas Adobes Wash
Figure 1.3 Casas Adobes Wash Soil Classification
Figure 5.1 The study areas for the three FLO-2D models.

2

Section 1 Introduction
1.1 Purpose
This Technical Data notebook (TDN) has been prepared for the Casas Adobes Wash
(CSA) located in Pima County, Arizona (Figure 1.1). The objective of the TDN is to
provide discharges and floodplain limits along the CSA using better 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, Title 48, Chapter
21, Article 1, Sections 48-3601 through 3627. More specifically, A.R.S. 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 A.R.S. 3609, this ordinance provides for protection of the
public health safety and welfare by regulation of flood and erosion hazard areas to
control flood hazards and prevent repetitive loss from flood damage.
D. The flood hazard areas of Pima County are subject to periodic inundation which
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 losses are caused by the cumulative effect of obstructions in areas of
special flood hazards which increase flood 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. (Ord. 2005
FC-2 § 2 (part), 2005).

3

Section 16 of the Pima County Ordinance 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:
Dave Stewart, EIT, Civil Engineering Assistant
Pima County Regional Flood Control District
97 East Congress, Tucson, AZ 85701

1.3 Project Location
The Casas Adobes (CSA) study area is located within Federal Emergency Management
Agency (FEMA) Flood Insurance Rate Map (FIRM) panels 04019C1680L, 1660L, and
1667L. The FEMA-designated “Zone A” flood-hazard area is specified for the length of
the Casas Adobes wash from upstream of the W. Sunset Rd. bridge to downstream of W.
Orange Grove Rd (Figure 1.2). A Letter of Map Revision with effective date of April 10,
2001 displayed updated topographic information along the CSA from approximately 420
feet north of Sunset Rd. to approximately 1200 ft South of Orange Grove Rd. The
objective of this TDN is to provide discharges and floodplain limits along the CSA using
updated topographic data, hydrologic modeling, and hydraulic modeling.
The detailed study reach for the Casas Adobes Wash (CSA) is from the W. River Rd.
Bridge at the downstream boundary to N. Oracle Rd at the upstream end. The CSA
enters the study reach from the northeast and a tributary to the CSA converges in Section
10 of Township 13 South, Range 13 East, Pima County, Arizona (Figure 1.2). A levee
has been constructed on the west bank of the CSA south of the confluence, and the
channel is lined immediately upstream of the Sunset Rd. Bridge to the CSA outlet at the
Rillito River (Section 15, Township, 13 South, Range 13 East).

1.4 Hydrologic and Hydraulic Methods
A hydrologic analysis was performed to determine the 100-year return period discharge
at concentration points along the CSA using the Hydrologic Engineering Center’s
Hydrologic Modeling System (HEC-HMS) and PC-HYDRO for the tributary. The
hydraulic analysis was performed to delineate floodplain limits along the study reach of
the CSA using the Hydrologic Engineering Center’s River Analysis System (HEC-RAS)

4

(USACE 2002) and FLO2D models in the upstream distributary flow areas. A box
culvert is located at the CSA crossing with W. Orange Grove Rd, and bridges are located
at W. Sunset Rd and W. River Rd. Storm drains are located at the W. Ina Rd. crossing
that have an outlet downstream of the N. Oracle Rd. crossing, where the hydraulic study
begins. The attenuation of the peak discharge from culverts and bridges was not included
in the calculation of the discharge to provide a conservative estimate.

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

1.6 Study Results
The CSA was divided into 25 sub-basins, and discharges were calculated at significant
confluences for floodplain mapping (Fig. 1.2). The estimated discharges are 1474.0 cfs
for the main reach at Las Lomitas Rd. (CP A) with an area of 1.42 mi2, a discharge of
1133.0 cfs for the tributary at La Lomitas Rd. (CP B) with an area of 0.518 mi2, a
discharge of 1987.2 cfs for the confluence with the Rillito (CP C) with an area of 2.22
mi2, a discharge of 1363.3 cfs for the main reach at La Canada Rd. (CP D) with a
drainage area of 1.06 mi2, and a discharge of 479.0 cfs for the tributary at La Canada Rd.
(CP E) with a drainage area of 0.15 mi2.

5

Figure 1.1
Watershed Map
Casas Adobe Wash

MAGEE

!
(

Discharge Point
Contour 10 ft.

Subbasin
CSAA001
CSAA002
CSAA003
CSAA004
CSAA005
CSAA006
CSAA007
CSAA008

INA

CSAA009
CSAA010

SK

CSAA011

YL
E
IN

CSAA012
CSAB001
CSAB002
CSAB003
CSAB004
CSAB005

CP E

CSAB006

!
(

CSAB007
CSAB008
CSAB009
CSAC001
CSAC002

!
( CP D

CSAC003
CSAC004

ORANGE GROVE

Aerial : 2010 Pictometry
Topo: 2008 Pima Association of Governments
Datum: NAVD 1988

ORACLE

!
(!
(

Index Map Scale 1:5,250,000

1ST

CP B CP A

LA CANADA

LA CHOLLA

Pima County Index Map

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.
Pima County Regional Flood Control District

ER

!
(

RIV

CP C

1,000

500

0

01/2011
\\gislib\rfcd\projects\imd\xavi\mxd\AKITSU\Casas_Adobe_wash\Casas_Adobe_Wash_Fig1_1.mxd

1,000 Feet

Figure 1.2
Study Limit
Casas Adobe Wash

MAGEE

ORACL
E

CSAA011

ORACL
E

MAGEE

CSAA009

(
!

Discharge Points
River

CSAA010

Subbasin Boundary
Existing FEMA Floodplain
INA

CSAA008

ZONE A

INA

ZONE AE

CSAA012
E
IN
YL
SK

CSAB008

E
IN
YL
SK

CSAA007

CSAB009

LA CANADA

ZONE X - SHADED
Aerial : 2010 Pictometry

CSAB006
CSAA005

CSAA006

CSAB007
CSAB004
CSAB005
CSAB003
ORANGE GROVE

CSAA003

(
!
CP D
CSAA004
Pima County Index Map

CSAB002

CSAA002
CSAA001
1ST

CSAB001

LA CHOLLA

Index Map Scale 1:5,250,000

!!
(
(

CSAC004

CP B CP A

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.

CSAC002

This product is subject to the Department of Transportation
Technical Services Division's Use Restriction Agreement.
Pima County Regional Flood Control District

CSAC003
RIVE
R

1,0 00

500

0

RIVER

Study Limit

(
!
CP C

ORACLE

CSAC001

01/2011
\\gislib\rfcd\projects\imd\xavi\mxd\AKITSU\Casas_Adobe\Casas_Adobe_wash_Fig1_2.mxd

1,0 00 Fe et

Figure 1.3
Soil Classification
Casas Adobe Wash
MAGEE

ORACL
E

CSAA011

Subbasin

ORACL
E

Soil Classification
CSAA009

Soil Group: A (100%), ARIZO-RIVERWASH
COMPLEX, 0 TO 3 PERCENT SLOPES

Soil Group: A (100%), RIVERWASH

CSAA010

Soil Group: A (100%), VINTON SANDY LOAM
Soil Group: A (53%) B (47%), VINTON-ANTHONY
SANDY LOAMS

Soil Group: B (100%),

CSAA008

INA

Soil Group: B (100%), ANTHONY FINE SANDY
LOAM, 0 TO 3 PERCENT SLOPES
Soil Group: B (100%), ANTHONY GRAVELLY
SANDY LOAM,1 TO 3 PERCENT SLOPES
Soil Group: B (100%), GILA LOAM, 0 TO 1
PERCENT SLOPES

INA

CSAA012
E
IN
YL
SK

CSAB008

Soil Group: B (100%), GILA SANDY LOAM

CSAA007

Soil Group: B (100%), GRABE LOAM

CSAB009
E
IN
YL
SK

CSAB006
CSAA005

CSAA006

CSAB004
CSAB005
CSAB003

LA CANADA

CSAB007

Soil Group: B (100%), PINALENO-STAGECOACH
COMPLEX, 5 TO 16 PERCENT SLOPES
Soil Group: B (50%) C (50%), PALOS VERDESSAHUARITA COMPLEX, 2 TO 8 PERCENT SLOPES
Soil Group: B (82%) C (18%), PINALENO-STAGECOACHPALOS VERDES COMPLEX, 10 TO 35 PERCENT SLOPES
Soil Group: C (100%), ROUGH BROKEN LANDPALOS VERDES COMPLEX, 0 TO 60 PERCENT SLOPES
Soil Group: C (50%), D (50%)
Soil Group: C (53%) D (47%), PALOS VERDESJAYNES COMPLEX, 2 TO 8 PERCENT SLOPES

ORANGE GROVE

Aerial : 2008 Pima Association of Governments

CSAA003
CSAA004
Pima County Index Map

CSAB002

CSAA002
CSAA001
1ST

CSAB001

LA CHOLLA

CSAC004

CSAC002

Index Map Scale 1:5,250,000

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.
Pima County Regional Flood Control District

990

495

0

CSAC003

RIVER

CSAC001
E
RIV

11/2010

R

\\gislib\rfcd\projects\imd\xavi\mxd\AKITSU\Casas_Adobe\Casas_Adobe_wash_Fig1_3.mxd

990 Feet

Section 2 FEMA Forms
2.1 Study Documentation Abstract for FEMA submittals
2.1.1 Date Study Accepted: This study has not been submitted to FEMA.__
2.1.2 Study Contractor:
Planning and Development Division,
Pima County Regional Flood Control District
97 East Congress, Tucson, AZ 85701
(520) 243-1800
Prepared by Dave Stewart, EIT, Civil Engineering Assistant.

2.1.3 Local Technical Reviewer:
Planning and Development Division,
Pima County Regional Flood Control District
97 East Congress, Tucson, AZ 85701
(520) 243-1800

2.1.4 Reach Description
A segment of the CSA study reach is located within a FEMA-designated “Zone A” floodhazard area, as depicted on FIRM Map Panel Numbers 04019C1660L and 1667L
(February 8, 1999). The detailed study reach of the CSA begins immediately downstream
of N. Oracle Rd. and ends at the W. River Rd. bridge.
The study reach of the CSA is primarily a sand channel with desert brush in the channel
and in the overbanks areas.

2.1.5 USGS Quad Sheets
Not available for this study

2.1.6 Unique Conditions and Problems
None.

9

2.1.7 Coordination of Peak Discharges
The 100-year regulatory discharge rates at the concentration points along the study reach
were computed using HEC-HMS and PC-Hydro for CP B and E. The HEC-HMS
discharges assumed no base flow in the watersheds and no transmission losses within the
reaches. All reaches were modeled with HEC-RAS. The discharge rates were acceptable
per Evan Canfield, Pima County Regional Flood Control District Project manager.

2.2 FEMA Forms
This is a local study and no FEMA forms are included in this TDN.

Section 3 Survey and Mapping Information
3.1 Field Survey Information
A box culvert is located at the Casas Adobes Wash crossing at W. Orange Grove Rd, and
bridges are located at W. Sunset Rd and W. River Rd. Storm drains are located at the W.
Ina Rd. crossing that have an outlet at the N Oracle Rd. crossing. A dip crossing is
located at N. La Canada Rd.

3.2 Mapping
The topographic data was obtained using GeoRas and ArcGIS. A triangular Irregular
Network (TIN) derived from 2008 Light Detection and Ranging (LiDAR) data was used
for the analysis.
The following data was used in this TDN;
Projection = State Plane, Arizona Central Zone
Datum = NAD83 HARN
Units = International Feet
North American Vertical Datum of 1988 (NAVD, 1988)
The contour interval of the topographic map is 2 feet.

Section 4 Hydrology
4.1 Method Description
The 100-year peak discharges at CSA concentration points with drainage area greater
than 1 mi2 (CP A, C, D) were calculated using the Hydrologic Engineering Center’s

10

Hydrologic Modeling System, (HEC-HMS) version 3.1.0, and the peak discharges at
concentration points with drainages areas less than 1 mi2 (CP B and E) were found using
PC-Hydro. The HEC-HMS model parameters for rainfall, topography, soil, vegetation,
and channel characteristics were determined according to the Pima County Regional
Flood Control District Technical Policy 018 (Tech-018). Tech-018 is included in
Appendix A.
The HEC-HMS and PC-Hydro models are included in Appendix D.

4.2 Parameter Estimation
4.2.1 Drainage Area
As mentioned in 3.2, topographic data was derived from a TIN created from 2008 LiDAR
data. ArcGIS was used to delineate the sub-basins. The watershed map is shown in Figure
1.1.

4.2.2 Watershed Work Map
ArcGIS was used to determine drainage areas from 2008 LiDAR data in Figure 1.1. Subbasins were delineated for the hydrologic analysis at CP A, C, and D in HEC-HMS, and
for the hydrologic analysis at CP B and CP E in PC-Hydro.

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

4.2.4 Statistical Parameters
No statistical parameters were used in this TDN.

4.2.5 Precipitation
According to Tech-018, the design storm should be used that produces the higher
discharge between the 100-yr 3-hour SCS Type II distribution and the 100-yr 24-hr SCS
Type I distribution. The 100-yr 3-hour SCS Type II distribution was found to produce the
higher discharge on the CSA.
The NOAA Atlas 14, upper 90% confidence interval precipitation frequency estimate
values (NOAA 14 rainfall) were used to determine point 3-hour rainfall depth for the

11

CSA watershed. The point rainfall depth for the 3-hour storm was obtained, based on the
coordinates of the centroid of the watershed. Area reduction factor was applied to
watersheds larger than 1 square mile as noted in Tech-018. The 3-hour rainfall depth for
the CSA watershed is 3.17 inches. The area reduction factors are 0.946, 0.938, and 0.970
for CP A, C and D respectively.

4.2.6 Physical Parameters
The physical parameters for the sub-basins and reaches of the HEC-HMS model are
summarized in Tables 1 and 2. As mentioned in 4.1, all the methods and parameters were
determined based on Tech-018. Table 1 summarizes the method used for a HEC-HMS
analysis.
Table 4.1 Methods used for a HEC-HMS analysis

Rainfall Depth
Rainfall Distribution
Rainfall Loss
Time of Concentration
Transform
Routing

Selected Method
NOAA 14, upper 90% Confidence Interval
3-hr SCS Type II Storm
SCS Curve number
SCS Segmental Method
SCS Unit Hydrograph
Modified-Puls

The SCS Curve Number (CN) method was utilized as a rainfall loss method in the HECHMS model. The CN was determined using the Curve Number tables and Hydrologic
Soils Group maps associated with the PC Hydro User Guide (Arroyo Engineering, 2007).
The CN was not adjusted for rainfall intensity or antecedent moisture conditions. The
SCS Unit Hydrograph method was used as a transform method. Impervious cover was
determined using the 2008 PAG aerial photographs. The combination of the kinematic
wave time of concentration method and the U.S. Natural Resources Conservation Service
(NRCS) segmented Time of Concentration (Tc) calculation (USDA-NRCS, 1986) was
used to determine Tc, based on the recommendation on Tech-018. The Tc was calculated
by summing the travel time for sheet flow, shallow concentrated flow and channel flow.
The Tc for sheet flow was estimated using the kinematic wave equation. Manning’s
roughness coefficient for sheet flow was obtained using Table 3-1 in Technical Release
55, Urban Hydrology for Small Watersheds (USDA-NRCS, 1986). The detail of the Tc
calculation is included in Appendix D.

12

Table 4.2. Physical Parameters for Sub-Basins
2
Sub-basin Area (mi )
A1
0.068
A2
0.059
A3
0.085
A4
0.145
A5
0.065
A6
0.126
A7
0.101
A8
0.076
A9
0.249
A10
0.276
A11
0.126
A12
0.040
B1
0.035
B2
0.074
B3
0.056
B4
0.049
B5
0.039
B6
0.052
B7
0.111
B8
0.064
B9
0.039
C1
0.055
C2
0.080
C3
0.020
C4
0.130

CN
86.1
89.0
87.4
89.3
89.3
87.3
86.1
86.5
85.2
86.5
83.1
88.7
87.3
88.8
89.4
89.3
89.4
89.4
89.4
88.6
87.5
83.0
86.7
83.5
88.6

Initial Abstraction (in)
0.249
0.182
0.211
0.178
0.170
0.217
0.225
0.172
0.256
0.258
0.383
0.146
0.186
0.177
0.163
0.162
0.198
0.187
0.171
0.175
0.204
0.293
0.276
0.373
0.200

Imp%
22.1%
26.9%
26.3%
26.4%
30.0%
24.8%
29.5%
44.5%
24.9%
16.9%
5.0%
43.4%
35.5%
30.1%
32.0%
33.3%
16.7%
21.3%
28.5%
32.3%
28.3%
26.4%
9.4%
5.0%
22.5%

Lag time (min)
10.12
15.50
10.04
18.17
13.53
12.92
15.72
10.33
13.35
14.70
11.59
11.84
6.78
10.81
16.49
9.34
9.38
12.53
19.88
16.81
17.45
15.45
11.94
5.46
24.68

Runoff from sub-basins was routed using the Modified-Puls method. A storage discharge
table for the channel routing was developed using the cross sections and slopes in HECRAS. The number of subreaches was calculated using the following method:
L
...................eq.1
T
Vw  1.5 * Vave .........eq.2
Vave 

K

L
...................eq.3
Vw

Therefore,
T
K
...................eq.4
1.5
K
N  ..................eq.5
t
where Vave is average flow velocity, L is reach length, T is average travel time, Vw is the
wave celerity (a conversion factor of 1.5 is used for natural channels), K is hydrograph
travel time, Δt is the time interval for computations in the model, and N is the number of
steps in the routing. Eq.4 was obtained from Eq.1, 2, and 3.
13

Table 4.3. Physical Parameters for Reaches
Sub-basin Number of subreaches
RCSA001
12
RCSA002
7
RCSA003
5
RCSA004
8
RCSA005
5
RCSA006
6
RCSA007
4
RCSA008
3
RCSA009
8
RCSA010
14
RCSA011
7
RCSA012
4
RCSA013
5
RCSA014
4

4.3 Problems 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
The time interval of the rainfall data used in this study is 5 minutes, while the simulation
time interval is 1 minute. The HEC-HMS model interpolated the 5-minute time interval
of the rainfall data to 1-minute time interval.
Warnings were produced in the HEC-HMS model stating that each hyetograph gage with
5 minute interval was interpolated to a simulation time interval of 1 minute.;

4.4 Calibration
No calibration was conducted in this study.

4.5 Final Results
4.5.1 Hydrologic Analysis Results

14

The 100-year peak discharges at the concentration points along the CSA were determined
using the HEC-HMS model. The results are summarized in Tables 4 and 5.
Table 4.4 Summary of sub-basin discharges.
Sub-basin

Area (mi2)

Rainfall
Depth (in)

Runoff
Depth (in)

A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
B1
B2
B3
B4
B5
B6
B7
B8
B9
C1
C2
C3
C4

0.068
0.059
0.085
0.145
0.065
0.126
0.101
0.076
0.249
0.276
0.127
0.040
0.035
0.074
0.057
0.049
0.039
0.052
0.111
0.064
0.039
0.055
0.080
0.020
0.130

3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17
3.17

2.05
2.29
2.18
2.31
2.34
2.16
2.13
2.33
2.02
2.02
1.65
2.44
2.27
2.31
2.37
2.37
2.23
2.09
2.34
2.32
2.21
1.64
1.92
1.68
2.22

Peak
Discharge
(cfs)
175.9
136.0
231.7
307.8
163.8
304.0
217.1
218.5
556.1
584.6
248.9
110.9
113.3
205.2
129.9
147.7
111.6
123.8
225.1
142.2
80.4
91.9
178.9
51.3
216.8

Table 4.5. Summary of 100-yr Peak Discharge Values
Concentration Point
Area
(mi2)
Name
Location
CP A
Main Reach at Las Lomitas
1.42
CP B*
Tributary at Las Lomitas
0.52
CP C
At the Rillito
2.22
CP D
Main Reach at N. La Canada Rd.
1.06
CP E*
Tributary at La Canada Rd.
0.15
*Runoff volumes are not directly calculated in PC-Hydro.

100-yr Peak Discharge
(cfs)
1474.0
1133.0
1987.2
1363.3
479.0

Runoff Volume
(in)
1.99

Time of Peak
(min)
134

1.95
1.98

142
122

4.5.2 Verification results
The 100-yr peak discharge was compared with discharges estimated from the USGS
Regression Equation 13 (RRE13) (Thomas et al., 1997) (Table 4.8). The comparison
shows that the modeled 100-yr peak discharge is slightly lower than the RRE13 discharge
for CP A and CP C, possibly due to the attenuation effects along the main reach. The
modeled 100-yr discharge is higher than the RRE13 discharge at CP B, CP D, CP E
which may be attributed to the steep slopes and shorter lengths of those reaches and the
use of the more conservative PC-Hydro estimate for CP B and CP E.

15

Table 4.8. Comparison of peak discharge with regional regression equations.
Name
CP A
CP B
CP C
CP D
CP E

Concentration Point
Location
Main Reach at Las Lomitas
Tributary at Las Lomitas
At the Rillito
Main Reach at N. La Canada Rd.
Tributary at La Canada Rd.

Area
(mi2)
1.42
0.52
2.22
1.06
0.15

100-yr Peak Discharge USGS RRE13 Qp
(cfs)
(cfs)
1474.0
1581.0
1133.0
796.6
1987.2
2092.5
1363.3
1307.9
479.0
297.3

Section 5 Hydraulics
5.1 Method Description
The hydraulic modeling for the CSA wash was performed using FLO-2D, Hec-Ras,
Version 4.0 (HEC-RAS), and HEC-GeoRAS Version 4.1.1.
2008 LiDAR data was used to create a Triangular Irregular Network (TIN) for the
detailed study area of the CSA wash. The locations of the stream centerline, crosssections, and banks of the CSA wash were determined using ArcGIS and 2008 PAG
aerial photos. The physical attributes of the wash were digitized in ArcGIS using the
HEC-GeoRAS extension and then exported to HEC-RAS to create geospatially
referenced geometric data (cross sections, and reach lengths). Other parameters for the
steady-state analysis, such as Manning’s n-values, culvert data, expansion and
contraction coefficients, boundary condition, and ineffective flow areas were manually
input into HEC-RAS. The hydraulic data obtained from HEC-RAS were then imported
into HEC-GeoRAS to delineate a floodplain in the study area.
The hydraulic analysis was performed for the study area that includes an area currently
mapped as FEMA Zone A. Steady flow analysis was performed to determine 100-year
water surface elevations in the study area by using HEC-RAS. As described above,
geometric data for HEC-RAS including the stream centerline, cross-sections, river banks,
and culverts were obtained using HEC-GeoRAS. The HEC-RAS data and shape files
(contour lines, flowpath, cross section lines, concentration points, sub-basins, and
floodplain limit) from the analysis are included on the CD.
The downstream boundary condition was assumed to be critical depth for the HEC-RAS
model. Using a normal depth downstream boundary condition was found to have no
effect on results above the Sunset Rd. bridge, and therefore the critical depth boundary
condition is justified.
The reaches upstream of CP A and CP B were found to flow over bank and leave the
channel, and therefore FLO-2D was used for those areas. The reaches of the Casas
Adobes wash were split into three areas for FLO-2D models which are displayed in
Figure 5.1. The HEC-HMS hydrographs from the downstream concentration point were
16

used as the inflow at the upstream boundary of each FLO-2D model. The hydrographs
from CP A and B were entered at the top of FLO-2D Area 2, while CP D and E were
used at the top of FLO-2D Area 1, and the hydrograph for CP D was used at the top of
FLO-2D Area 3 (which results in a breakout flow path that connects to the tributary in
Area 1). A base floodplain Manning’s n value of 0.045 was used in the FLO-2D models
and then calibrated based on the roughness adjustments made by the FLO-2D software.
Houses were removed from the effective flow area by using the area reduction factors in
FLO-2D. The FLO-2D models are included in Appendix E.

Figure 5.1. The study areas for the three FLO-2D models.

5.2 Work Study Maps
The work study maps are included as Exhibits.

17

5.3 Parameter Estimation
5.3.1 Roughness Coefficients
The Manning’s n values were assigned based on USGS publications on roughness
coefficients for Southern Arizona (Phillips and Tadayon, 2006). A Manning’s n value of
0.045 was assigned for the channel and 0.055 was assigned for the overbank due to
scattered desert brush. In FLO-2D, the n values were calibrated based on the roughness
adjustment performed by the FLO-2D software.

5.3.2 Expansion and Contraction Coefficients
The channel of the Casas Adobes Wash is assumed to have gradual transitions and
default expansion and contraction coefficients of 0.3 and 0.1 were used respectively.

5.4 Cross-Section Description
HEC-RAS Cross sections were created using GeoRAS at changes in channel geometry
from the 2008 LiDAR data. The cross-section lines were drawn to be perpendicular to
flow paths in Geo-RAS and ArcGIS. Cross sections were not created for FLO-2D.

5.5 Modeling Consideration
5.5.1 Hydraulic Jump and Drop Analysis
No hydraulic jump or drop was shown in the analysis of this study.

5.5.2. Bridges and Culverts
The Sunset Rd. bridge was modeled at the downstream end of the study area using the
“As-built” plans for the Casas Adobes wash levee at Riverside Crossing (Environmental
Engineering Consultants, Inc. 12/18/98) included in Appendix C. The bridge at Sunset
Rd. consists of four 12’ x 8’ cells.

5.5.3 Levees and Dikes
The Riverside Crossings Levee is located on the west bank of the CSA wash from
immediately upstream of W. Sunset Rd. up to Las Lomitas Rd and was accredited by
FEMA on July 24, 2009 (Appendix B). The 2008 LiDAR data were used for the levee

18

features in HEC-RAS cross sections. “As-built” plans for the CSA levee (12/18/98) are
included in Appendix C.

5.5.4 Island and Flow Splits
FLO-2D was used for the reaches of the Casas Adobes wash where significant flow splits
and breakouts were found.

5.5.5 Ineffective Flow Areas
Ineffective flow areas were defined in HECRAS for areas of cross sections that were not
hydraulically connected until the water surface elevation exceeded a topographic feature.
Ineffective flow areas were set as permanent for large areas not connected to the channel
that would otherwise cause instability in the model when the water surface elevation
exceeded the ineffective flow elevation.

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
The FEMA guidelines state that it is required to run hydraulic models for the subcritical
flow condition. Since areas of the CSA wash have steep slopes and a lined channel, the
flow regime of the CSA is expected to exhibit critical flow at some locations. The HECRAS modeling produced some warnings stating “During the standard step iterations,
when the assumed water surface was set equal to critical depth, the calculated water
surface came back below critical depth. This indicates that there is not a valid subcritical
answer.” The program defaulted to critical depth at several HEC-RAS cross-sections
along the lower reach of the CSA. Most of the warnings force a critical solution which is
reasonable for these steep watercourses. A summary of errors is available in Appendix E.

19

The warnings stating that “The energy equation could not be balanced within the
specified number of iterations. The program used critical depth for the water surface and
continued on with the calculations”, “The energy loss was greater than 1.0 ft (0.3 m)
between the current and previous cross section. This may indicate the need for additional
cross sections”, and “The conveyance ratio (upstream conveyance divided by
downstream conveyance) is less than 0.7 or greater than 1.4. This may indicate the need
for additional cross sections” are produced at some locations in the Casas Adobes
HECRAS study reach. These warning messages were expected due to the steep slopes of
the CSA wash. All the warning messages in the HEC-RAS modeling are included in
Appendix E.

5.8 Calibration
The FLO-2D models for the Casas Adobes wash were calibrated for roughness to
improve model stability and speed. The TIME.OUT and ROUGH.OUT files were
reviewed and the cells causing increases in time steps were replaced with the higher
roughness values.

5.9 Final Results
5.9.1 Hydraulic Analysis Results
The Casas Adobes wash 100-yr floodplain is shown in Exhibit 1, Sheets 1 through 3.
The HEC-RAS model of the CSA is included in Appendix E.
The lower reach of the CSA (from CP A and B down to CP C) is considered a confined
wash at some locations and additional floodplain restrictions may apply. The ratio of the
average width of the 100-yr floodplain to the 25-yr floodplain was found to be 1.22 for
the lowest reach (lower than the 1.25 criterion), and at some locations the overbanks are
higher than 1.5 times the 100-yr flow depth. The CSA is not considered a confined wash
in the reaches above CP A and B.

5.9.2 Verification of Results
The floodplain limit obtained by this study was compared to the current FEMA
floodplain limit. The proposed floodplain approximately follows the existing floodplain
limit; however, this study extends further north and covers both the tributary as well as
the main reach. The results within in the current FEMA floodplain suggest that the
proposed floodplain limit is reasonable based on the new topographic data of the Casas
Adobes Wash.

20

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

Section 7 Draft FIS Report Data
7.1 Summary of Discharges
Table 7. Summary of Discharges
Name
CP A
CP B
CP C
CP D
CP E

Concentration Point
Location
Main Reach at Las Lomitas
Tributary at Las Lomitas
At the Rillito
Main Reach at N. La Canada Rd.
Tributary at La Canada Rd.

Area
(mi2)
1.42
0.52
2.22
1.06
0.15

100-yr Peak Discharge
(cfs)
1474.0
1133.0
1987.2
1363.3
479.0

7.2 Floodway Data
Not applicable.

7.3 Annotated Flood Insurance Rate Map
Not applicable.

7.4 Flood Profiles
Flood profiles are included in Appendix E.

21

2350

23

70
SEE SHEET 2 OF 3

236

40

Exhibit 1
100-year Floodplain
with cross sections
Casas Adobes Wash
Sheet 1 of 3

0
239

5

2360

23

2370

0
23
8

G

2360

M
N

50

O

23

AN

PO

55

5

2350

23

236

2340

EL
O

2340

A
N
O
R

235
0

U
TI
B
E

ESCONDIDO

LL
A
C

R
O
23
7

0

N

MONTEBELLA

U

35

!
(

0
23
3

FOUNTAINS

232

2320

CasasAdobes BFE Contours 1ft

5

2310

C
232

L
AL

E

CasasAdobes BFE Contours 5ft

O
KIN

Cross Sections

0

23

0

23
2

2300

2305

L
CA

10

L

I BU
T
E

R

ON

Study Area

!
(

381
6

Shallow Flooding Zone

0

CP A

Casas Adobes FLO2D Floodplain BFE FlowDepth

2300

3620

2296
.291

229
6

LAS LOMITAS

=>0.200

.874

LA CANADA

2295
.235

3478

2292
.566

3413

229
1

U
V
V
U
V
U
V
U
V
U
V
U
V
U
V
U
V
U
V
U
VU
U
V
3329

2290.082

2289.499

3265

Aerial : 2010 Landiscor Aerial Imagery
2287.365

3100

E
ORACLE JAYN

2978

0
227

2861

2824

2765

2717

2608

2506

2270.547

2284.204
2282.936

E

V

2280.318

2276.982

Topo: 2008 Pima Association of Governments
Datum: NAVD 1988

2275.994

2271.853

227
0

2270.132

2393

L
A
A
IST

2285.203

S STATION

2661

U
V
SUNSET
V
U

A
SH

2286.184

3037

2270

=>2.000

2287.996

3175

0

=>1.000

2310

0

48

2330

0
23

.806

231
0

2270

2290.9

=>0.500

GRANDE

0
0

V
U

2
23

0

3725

2300

0
23

0
23
22
9

U
V
V
U
V
U
V
U
V
U

!
(

CP B

2305

0
230

2300

Casas Adobe 100-yr Floodplain

3534

7
22

River

LAS LOMITAS

15

23

2280

Contour10ft

2325

2310

2320

0

2310

LA CHOLLA

5
23
235
0

2315

2320

2320

2320

2320

2320

RUDASILL
2330

23

30

2350

0

PLACITA C

0

2
23

Discharge Points
2008 Contour 2ft

2335

232

RUDASILL

HICO

23
3

0

B
TI

2330

A
IT

23

2340

2325

C

0

234
0

2345

A

CORONA

PANORAMA

0
236

PL

234

2330

2330

45

50

23

23

FOUNTAIN PLAZA

2335

A
VI

IG
T
LA

O
SUNSET

44
6.1
226

E

KLAMATH

COACHWHIP

HOPBUSH

LA CANADA

PAINTBRUSH

Index Map Scale 1:1,500,000

WHISPERING HILLS

POMONA

ORACLE JAYNES STATION

MESQUITE B
AF

ER
RIV

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.

HUDSON

HUDSON

This product is subject to the Department of Transportation
Technical Services Division's Disclaimer and Use Restrictions.
Pima County Regional Flood Control District

0

100 200

NEOSHO

RIV
ER
ROLLER COASTER

ER
RIV

T
GEN

RO
LE B

OK

SUNRIVER

HANSEN

!
(

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FLINT
ALDER GROVE

L
R
E
T
WA

CP C

Pima County Index Map

KEVY

2260.992

O S Q UE

LA CHOLLA

1310

OK

POMONA

V
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AN

2264.24

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1510

K EN N

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170

WILLOW THICKET

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BRAMBLE BROOK

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2
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67
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LV
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2268.356

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

10/2011

gislib\rfcd\projects\imd\xavi\mdx\AKITSU\Casa_Adobe\Casas_Adobes _Exhibit_1_s1of3.mxd

400
Feet

Exhibit 1
100-year Floodplain
with cross sections
Casas Adobes Wash
Sheet 2 of 3

MAXIMILIAN

BA

R

AR

GIACONDA

PENNY

M
O

AI

KH

PALOMA

KH

AI
BA

CASPIAN

CASPIAN

R

!
(
CHULA VISTA

KENANNA

2465

247

PALER

MIDDLETON

5

2455

2450

24

70

2465

River
70

2440

24

Study Area

70

2450

2430

S
LO

OS
L
I
F

2465

ME

2445

2410

2465

Shallow Flooding Zone
24

2460

RA N

SESA

CP E

Casas Adobe 100-yr Floodplain

2430

HAR

!
(

2460

0

2455

243

2435

MONTENEGRO

65

LA
CO
NI

LA CANADA

N
SA

2435

0
24
0

SAN IGNACIO

2420

2415

LA CANADA

2400

LEONARDO DA VINCI

2420

2400
0
23
8

CAMINO DE COROZAL

2360

2390
23

SAHARA PALMS

80

VIA CABALLO

This product is subject to the Department of Transportation
Technical Services Division's Disclaimer and Use Restrictions.
Pima County Regional Flood Control District

IA

75

SAFARI

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.

0

100 200

E

70

LL

23

65

CA

23

DE

LM

ED

2370

0
23
7

EL
O

CALLE TIBURON

55

2360

G

Index Map Scale 1:1,500,000

0

AN

VIA TIERRA

VIA RANCHERO

MONTEBELLA

IS

5

MONTEBELLA

23

0

CALLE KINO

23
50

235
0

OA
S

A

236

50

2330

2440
2440

2395

23
9

2380

A
MONTEBELL

2380
2370

2360
0

90

9
23

23
5

M AL AG A

238

2360

2350

VIA HACIEND

5

90

2360

Pima County Index Map

0

23

2360
23

23

45

0
24

5

2370

0

CORONA

23

0
237

235
0

CA

2370

7
23

2350

2450

S

24
1

ANTAS

2400

PLACIT
A DE S

0
239

0

ST
A
VI
A
LL
O
H
C

00

RAN

PLACITA

PLACITA DE ZACATAL

23

2340

SEE SHEET 3 OF 3

5

238

60
2360 23

2335

239

2385

2350

2345

2340

60

0

24

240

95

BA R

ALINADA

2375

40

50

0

23

CITA

RRE O N
MINO DE TO

HOSPITAL

23

24

2425

0
24

24

65

PLACITA
PLA

0

2350
235
0

0

CP D

CARAVAN

2370

2355

5
23

!
(

APPIAN

SAN MIGUEL

2390

PLACITA DE OCAMPO

236
0

5
23

0

ORANGE GROVE

CA

60
3
2

25

2370

2380

23

2360

Datum: NAVD 1988

SANTO DOMINGO

2410

2400

2360

Topo: 2008 Pima Association of Governments

30

24

75

ORANGE GROVE

MEDICAL

45

2425

5

90

0

Aerial : 2010 Landiscor Aerial Imagery

SAN LUCAS
85

7
23

244

45

2400

23

24

0

23

C

AL
TO
S

SANTO DOMINGO

23

VISTA LEJOS

NA

LU

S

10

240

2410

238

C

O
R
O

0

2435

LO
S

AS

24

2420

2380

23
8

AN

2440

2430

24

0
240

2410

=>1.000
=>2.000

24

LA

40

EL

35

EB

24

NT

2455

0
242

=>0.500

2460

2450

MO

45

0

24

L

LOS ALTOS

24

1
24

2440

2420

AH

Casas Adobes FLO2D Floodplain BFE FlowDepth
=>0.200

2425

2440

AM

Cross Sections

24

C

CasasAdobes BFE Contours 5ft

60

2470

MO

24

2465

POMONA

IM

CasasAdobes BFE Contours 1ft

5

GI

SS

ED

245

MA

M

2445

CA

TARANTULA RANCH

2470

AH

Contour10ft

DESERT HARBOR

2465

SIM

2008 Contour 2ft

2475

CHULA VISTA

CAS

Discharge Points

SEE SHEET 1 OF 3

PANORAMA

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

10/2011

gislib\rfcd\projects\imd\xavi\mdx\AKITSU\Casa_Adobe\Casas_Adobes _Exhibit_1_s2of3.mxd

400
Feet

VILLAGE

NORTHERN

OPUNTA

YUCCA VIA

VIA PISA

SIENA

ANTONIETTA

INA

INA

VI

FIRENZE

VIA PONTE

PAMPA

INA

MONTECATINA

VIA ASSISI

LA OESTA

PASEO DEL NORTE

OLD INA

Exhibit 1
100-year Floodplain
with cross sections
Casas Adobes Wash
Sheet 3 of 3
!
(

Discharge Points

A

2008 Contour 2ft

NE

VE
A
ZI

Contour10ft

GIACONDA

CasasAdobes BFE Contours 1ft
ALPIA

CasasAdobes BFE Contours 5ft
2530

2525

GIACONDA

2500

=>0.200

24

E CAL

2470

TA

24

E

50

CA S

CL
ORA

LOS ARBOLES

2455

LE L
OM I

60

EUCALYPTUS

Datum: NAVD 1988

CAL

24

AB AZ A

S
2460

Topo: 2008 Pima Association of Governments

CASAS ADOBES

CO RT

LE
ORAC

75

ANDREA DORIA

Aerial : 2010 Landiscor Aerial Imagery

2470

2460

65

=>2.000

FLORENCE

2470

2460

I CO L A

24

=>1.000

UNNAMED

NANINI

2470

95

70

70

2465

=>0.500

POMELO

24
24

N
TO
R
U

2490

2485

5
2480

2465

GE G

2505

2485

90

85

247

LOS ALTOS

45

LE
ORAC

SANTO DOMINGO

WHITE ACACIA

Pima County Index Map
GREER

LILLIAN

SCHUMAN

MARIA

2460

RO V

E
2505

MARIA

2500

2480

24

24

2480

2465

SAN N
2450

ORA
N

250

5

VISTA
PLACITA CHULA VISTA

85

2465

2515

Shallow Flooding Zone
Casas Adobes FLO2D Floodplain BFE FlowDepth

2450
24

Casas Adobe 100-yr Floodplain

2510

B

24

SAN LU

Study Area

2505

70

2465

0

2515

2510

2495

2490

24

2475

2470

2465

24

252

River

CHULA VISTA

2480

MIDDLETON

20

15

2495

25

25

2505

2510

SEE SHEET 2 OF 3

PALOMA

Cross Sections

VISTA GRANDE

ROSE

TRE

AS

UR

E

Index Map Scale 1:1,500,000

BARCELONA
E

This product is subject to the Department of Transportation
Technical Services Division's Disclaimer and Use Restrictions.
Pima County Regional Flood Control District

RE
E

RUSHWOOD

UNNAMED

YUCCA

0

100 200

BARCELONA

ARABIAN
ZAMA

SPARKL

SAFARI

POMELO

MINARET

HA
SA

OASIS

E

AGIDIR

WINDEMERE

MIRAG

ME

ET

M
PA
L
RA

SALO

NG

SAHARA PALMS

OR
A

UNNAMED

S

CARAVAN

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.

ORANGE GROVE

WILLOWBROOK

DESERT PALMS

ORANGE GROVE

MARAKESH

SAN IGNACIO

SAN MIGUEL

RUSHWOOD

MILLBROOK

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

10/2011

gislib\rfcd\projects\imd\xavi\mdx\AKITSU\Casa_Adobe\Casas_Adobes _Exhibit_1_s3of3.mxd

400
Feet

A.1 Data Collection Summary
Aldridge, B. and J. Garrett. 1973. Roughness Coefficients for Stream Channels in
Arizona. US Department of the Interior Geological Survey. Tucson, AZ.
Arizona Department of Water Resources, Flood Mitigation Section
“Requirements for Flood Study Technical Documentation” SS1-97, November 1997
National Weather Service. 1984. Depth-Area Ratios in the Semi-Arid Southwest
United States, NOAA Technical Memorandum NWS Hydro-40
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.
Phillips, J., and T. Ingersoll. 1998. Verification of Roughness Coefficients for Selected
Natural and Constructed Stream Channels in Arizona. U.S. Geological Survey
Professional Paper 1584.
Pima County Regional Flood Control District
“Pima County Mapguide Map”, 2008
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). 2003. Geospatial Hydrologic Modeling Extension
HEC-GeoHMS, (v 1.1) CPD-77, 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.

A 2. Referenced Documents
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.
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. Department of Agriculture Natural Resources Conservation Service (NRCS), 1986.
Urban Hydrology for Small Watersheds, Technical Release 55. Washington, DC.

Appendix B General Documentation and
Correspondence

Appendix C: Survey Field Notes

Appendix D: Hydrology
Supporting documentation is included as digital data on the CD.

Appendix E: Hydraulics
Supporting documentation is included as digital data on the CD.

Appendix F: Erosion and Sediment Transport Analysis
Supporting Documentation
None