FINAL PLAT: ARROYO NORTE UNIT 4 CASE NUMB - P AND Z PACKET DISTRIBUTED AT BOARD MEETING

Report to the Board of Supervisors
Prepared by the Maricopa County Planning and Development Department
Commission Hearing Date: September 6, 2007
Board Hearing Date: September 3, 2008 (Continued from August 20 1 2008)
Case: S2006015 - Arroyo Norte Unit 4
Agenda Item: 3
Supervisor District: 3
Applicant: Hoskin Ryan Consultants
Property Owner: Pulte Homes
Request: Final Plat in the R1-7 RUPD zoning district
Existing On-Site and Adjacent Zoning:
On-site: R1-7 RUPD PAD (Z2002092)
North: R1-8 RUPD PAD / Arroyo Norte Unit 5 and R1-10 RUPD
PAD / Arroyo Norte Unit 6
East: R1-18 RUPD PAD / Arroyo Norte Units 8 - 10
South: R1-6 RUPD PAD / Anthem Unit 21-A
West: R1-7 RUPD PAD / Arroyo Norte Unit 3 (City of
Phoenix)
Proposed Use: 100-lot, 4-tract, single-family residential subdivision
Site Location: East of I-17, south of Circle Mountain Rd. (in the
Anthem area)
Site Size: Approx. 38.6 gross acres
Proposed Density: 2.59 d.u./ac.
County Island
Status: N/A
Summary of Conformance with Adopted Plans:
County Plan: The County Area Plan designates most of the site for
Large-Lot Residential (1-2 d.u./ac.) uses, but allows for
Scenic Commercial uses along the highway frontage.
The proposal is, arguably, in concert with the County

Area Plan because of allowance for increased density
for preservation of open space connections to Gavilan
Peak determined at time of Arroyo Norte's zoning
entitlement.
Municipal Plan: N/A
Support/Opposition: There is organized neighborhood opposition to the Arroyo
Norte development project, but no written opposition has
been provided specific to this Final Plat since there has
been no related public notice and none is required for a
Subdivision case with approved Zoning.
Discussion: The Preliminary Plat was first approved by the Planning & Zoning
Commission on August 11, 2005 (S2004107). It was subsequently
extended on August 3, 2006 (S2006048) and September 6, 2007
(S2007044). The current Preliminary Plat will expire on September
6, 2008. If the subject Final Plat is not recorded prior to that date,
the Preliminary Plat will expire. Further, conditional zoning approved
under case Z2002092 will also be positioned for revocation.
The applicant has complied with ARS 9-474, as amended in 1978, by
routing a copy of the final plat to , the all municipalities within three •
miles of the subject property and to all intended utility providers.
There were no objections to the request raised by any of these
entities. A Certificate of Assured Water Supply from Arizona
Department of Water Resources is also included.
All requirements of the Maricopa County Department of
Transportation, the Maricopa County Environmental Services
Department, and the Flood Control District of Maricopa County have
been met. All agencies have signed-off on the final plat; however,
issues regarding Drainage Review remain outstanding on the
associated Infrastructure Permit (B200603115).
On August 14th the applicant submitted revised improvement plans.
On August 18th the applicant was provided with Drainage Review
comments (attached). If the applicant makes a resubmittal that
adequately addresses these drainage design issues prior to the
September 3rd BOS meeting, staff will recommend approval of the
final plat.
Staff
Recommendation: Continue indefinitely
S

Planner: Robert Kuhfuss, AICP, Senior Planner
• Reviewed by: Darren V. Gerard, AICP, Deputy Director
Attachments: Case and vicinity maps (2 pages)
Final Plat (6 pages, reduced 8.5" 11")
Letter from the applicant (1 page)
ADWR Certificate of Assured Water Supply (1 page)
Drainage Review comments (3 pages) _
Enclosure: Final Plat Mylars
•
•

MARICOPA COUNTY, ARIZONA
SUPER'VISORAL DISTRICT NO. 3
REQUEST: • . .
ARROYO VISTA UNIT4
FINAL PLAT
R1-7 R.U.P.D. / PAD. ZONING DISTRICT
(39.58 ACRES) -
•
•PLANNING -141ARMOPA DEvti-ORMENt COUNTY
• PHOENIX, ARIZONA .

MARICOPA COUNTY, ARIZONA
Seclion: 10 Township: OSN 02E
1. SUPERVISORAL DISTRICT NO. -3..
REQUEST:
• ARROYO VISTA UNIT 4 -
• FINAL PLAT. - •
R1-7 R.U.P.D. / PAD. ZONING DISTRICT
(39.58 ACRES) •
• MARICOPA COUNTY . 1 "= 2 500 '
- PLANNING • PHOENIX; &DEVELOPMENT- ARIZONA • -

: K 1 1 1 ;of 11 4 g : 11 i Ph lit i I i ;-1 iit wiN roof Oil iii 0 ael is .
1 • f g gis to 1 0 hi 1 I ii ii :1 b ri 1 :i ;I Ad, quo,. 4411 1 U
1 gi 111T1 1 I ilh 1 i ii ill 1 1 1 I j di 111 1111 ii i
11 ! 1 11 l'ili IA ' 1 ig 2 1 It :' 10 id 11 r I 6 pig ..... I...1 ill. g 6 .-rin , de. %VA NO .
.. 3 A h 4 Ilill 44 ! iii 44 ! !I 4 II . l'i d 3 h„,im AIR
5
V Iv !
1 10
5 3 3 5
PI
Pm Ii
251
!Mg gid 1!4 Op I pIi
104421 NI:114i 0% :AI 151
101hP POO 11 :Ng iti% le 12i ! I 110 .s "
41P1011 1141401 togli ogle WO Ohl r ir g ga II I.
iN!gi4 0,1k% suithtll If;li Ipw hot i...0 I ;04 mg • 111 tit I.. 11; .1_,
.111k. aa ma " oil ailr 1 lir I a g .1a

Lgr AltitA 'KAU
"ARROYO N9RTE - UNIT FuRRUPD Loss
=la
Si
MAW NT27W .N7I-111 MUMMAU/PULA 1•171•1111::.1111021711 ' I
ZONING CHART - PER ZONING CASE 22002092 imam MAN II r.-:-AsW=A F7A1111C-'.. IILM11 2-,"11 W71I• 117:11111AIIIIILW INLL'EA I
:Ma y LOT1 IONIT mostsus WWI 1440 NONAIIONI IN UN VI LOT IN VT INEA Lut wan 441 M. ELBE MN 147.71NI 11711111 743711 VFW NI LANK=,//
WM CO NIT I as stirat sal NB WI 01111140 WIWI KM MAW 1747.1 W =IA INT1WINIFF..11W=A1 win in_=an wilzan
amixa 1 4 I - MO P7 wilt I V VW WI1111 7:111 IEW
NA1110 NMI NI WNW TO IV NOM WNW 1110111110174 NMI INV 20 INVOL 1477,11c=1 =rim orwillEUJI 111_:.111 IWO!
ELM=.r-V. Nr.71M 11471•11111‘111W-I, _.Za
WHIMsime 1.1.1.1.111
MAI IVAN 114.Th r'.11W.M1I ., 2,14/1 VIM 4111._a1WW V4_,20 Wa:.//
NEMt 117:7111•F2Tia fi:1111t LEA
INLIIM17.71NIUEra MAE INT7WIE =AI IW"RM IN.1/1:7/ Wat -
111_1•1•77NIIIL
MEM I _44-7• W
NUM,
MUM 141:711N 111,M1111112,1W
ULAN I- 4.71M INT= III EL:20 C:LI:11
MLLI• M111117:71111117734 E NrAll
NOT A PART ELIE 114:7311
AM1110:1034114 FILM VT.'. NM L=11 W FLU ailLAI
PLEASE REFER TO THE MAW 1-4:7 VIvslmin NC= 1W4a111111:21:14
'ARROYO DEDICATION NORTP 10. 196. MAP P0.50 OF MAW(TAW MEAN friTNI OVUM I 11117111111 was nty.Lains..!,,I.AI
MCA, FOR ARROYO NORTE ELM1111111.Tral Wall r2im 111:17,11 ormi in !Zig saLL.An
DRIVE DEDICATION RIGHT INFORMATION OF NAY WWI IFETAN 114=11 111171111111111 NUINI WIDE
IVAN IFFT: II III :147a NI All 1110.12,1W
MAI N I W EEFA 111711•!!IIM I
WEI- 114=1/111=.41 111:7111114..,1•2_411
1111-1• 177.11•1111=,111 1114.1.11104:1141
MAW =11 win st L.nsi ILIA!
!LW! FEW KI-17:-,2i
1111E1•17:7.71 WFM• If =NI WTM 1•711111.4:iNICLISII NL:2- r"All
ELM •!IMt WEIN •ILLIN RISEN
MAN IVO 111111=A NIFTWI •LI1D120L!111
MUM 177/11 .. WIT11 114:::41C1-1141
MAI 1[47.-W Ersuli nEca:A
MAN MAN 114.7111111IMM 47,11111ff WITINI =rum !CUM Is Lax Ill',1141 Walla
WWI .6:111WMa 111E2:11
MtAI Ur. 2.111 Erin.,a
ML_IM Nic-,111E =1/1 WIT111 VEEN. lla-'41
Nr47N111r777
SIIEET 4
6
LEGEND
um sum min is Ism as us
Krum WM= so ORM Cr NY 47V0
• —41-- POI Mt VA UR SW Mum= WV CIF
' ORM OMER
O 0001 MIR IS NM
NOT A PANT 1 O 001 Vica
Arts A0241414D U IIO Ull ORR MEI
RR PAL 004111110 UMW
RR MC MUM 0110311
KEY MAP Mt ISOM 11111400 mew
VW WNW NW OW VW
NTS IN WENN WAFT SAM
NW SOL WWI
ON101
1111114-W
OF ste
IMAIN UN
4144 WV
emnmrMt NUSII
• um fit me No
to
-11ACVW
1111Hooldn Consullsids. asausermassos Inc.
GROSS AREA 35.36 AC. 0•4404.14140a
SHEET 2066 liraRI 1110.5104014.11010111114441.00.0 mg
AUNNWWM YeItOim 1 41410404•4411 0111110•00441 001044
FINAL PLAT MOW MORIN UNIT 4 05-0811

!! ii
a
a
- U.
111
II
glgUICISEKINGLOMIRI =NEM. EDIVIt
azatataaasaa
^
WM ICU
1119171
ammo ammr*
=WWII
2101111 MEM
I/X211 0011121 NAL mama
Ole

WONTED
-e- latmecomme•iensamir suve •miumnua gns ow Marra an mem
MMAIMAZIMITVAI COPA inalar MMI . 10 sus tar rarrvil ammit
1 0 Welt AM MA PIAI M UI =I URI
12/ IIII UV VuMUM= GI OVA MEI ROM
Al ,.0 WM_ IMMO "ff urs unti e 11/111Uallal
INA AMA AVAillIVAAV
MATCEI SORT 3
VI
munn 1211.
illoskIn•RyanConsultants Inn.
SETTAPETTFOX SEBUM 2 FOR 11211magirr In BMW f GROSS AREA 33.36 AC. PINAAAAS Nisymni,g,
ZONNICBART MAMA DATA FORCURVE DATA YORLINIDATA sum 4 OF 6 NAPA MAN I 041n1111 I M.111110111A•
/SUM UOIMMOIMINWPOOMMOMWMINICOMMINNWILOMMO4L

1
MATCH SHOT 4
jIl
LEGEND
WM CRIER Rue Al NIRO au --
—•— SR ORM VI *AIM PIM= PM NOMA CP MAJ
is WO ut MR sauvrtam moo; noi - V str ova at
ORM OM=
0 MIMI FON MR
CAI ORM PACO
IA 0 UR OM CUM NAIR
Mt tau aim= maw
RI ROLM MIT KAMM
NMI RPM MINIM MINI
WS MOM NG OPEN PACK
MCA MOM COPT IRMO
PRO ROW MVO
---- KUPER IJK
OPPT-Cf-IP 1.1M
---- SHflSHI(P EMI
KUM UP ON MGT FOR Igr/415' NIALPPA-
NA avA PITS GOND.OaiAla
MIPT SRN LIM MARPR
WTI • IMO RAM Illieskla•lim Comae, Ino.
NO RIGHT-OF-WAY DISTURBANCE SHALL OTHER OCCUR THAN THAT MINN ASSOCIATED AREAS SHOWN WITH ON IMPROVEIENTS INS SHEET THAT WITHIN NAVE THE BEEN PUBLIC I GROSS AREA 3536 AC. promimedt soft amp
DESIGNATED AS NAOS EASEMENT AND Man EASEMENT SHEETS 0P6 ImoloOMPRIROMPPemilmorAmA.
,714/737-7.
FINAL PLAT MOTO NORTE UNIT 4 05-C41

iiiiiiIHiiiuiiiiiiiuuiiuiiiisfluiiuiiiiulliniIi
21-1-EDEEEEEMEED 11711711111111111111111111111011111M4
iiii - r lablhadbib "- hhhIiiii IflhIkl
:EEEMEE,EEEEEEEEEEEEE:
Pi

• .. • • • 1::?-"Y . • . .• )1
Hos.kin Ryan Uansultahts
• * • "rteafIV414glieerIng stoisti;hr • -
..• February 7, 2005
Board of Supervisors
Maricopa County Planning & Development
501 N.44111 Street. -
Suite 206
Phoenix, AZ 85008
•
•
•- RE: Arroyo Vista •
Gentleman: .
-• We are designing a residential Subdivision named Arroyd Vista located on .
• roughly 157 acres at Circle Mountain Road and Gavilan Peak Parkway ; acated
within tvlaricopa County. . .
-
The owner of this property is Pulte Homes Corporation, located at 15111 N. Pima
Na., ScottSdale, AZ 85260,
•
The engineeron this project is Hoskin Ryan "Consuttants, Inc., 201 W. Indian
•School Rd„ phoenix, AZ 85013 - .- •. • .
: - • -
.•• • Letters Fiave been addressed to cities within three . miles of the plat Letters have
been enclosed in Submittal package. • • •• : . -• . . • . .• .
. . -. .
If you need any additional information or have any questions, please feel free to
-. - contact meat 602-252e8384. .
- Thank you-
-
. Ted A`. Luther,
• . Sr Project Manager
-11./dk . •
RECO MAY 1 V.
00 6015-
, . S2 011603115
-
. 201 West . Indian . . : School Road, Phoenix. AZ 850114203 I Office: (60) 252.8384 I Fax: 002) 252.8385 1 vim - ,hoskinrya .- atom
. Land Planning „ I .Hydrology I Land Development L Civil infrastructure I Surveying j Construction Services [ Graphic Services

„.
• STATE OF ARIZONA -
- DEPARTMENT OF WATER RESOURCES .
5I •1/4 SUPPLY
This is to certify that
It *Michigan
bas met the — AILS. §§ 45-576 and the appli and...
By powers of the Arizona Department of by the
State of Arii.o Is the conditions contained in the ations,
• of Assured Water
" County, Phoeinz
•
Siifficient water of - will be continuously available demand of
--the referenced ei one hundred years. The referee 11 '1 of •
• 291 lots as desca lilt .1 plat on file with the D II
water &nand of Per year. The subdivision will be • I' .
Project water and water leased from the Ak-Chin
Americ' tan Water Company.
• 111 invalid as to any entity not •I1,
• be assigned pursuant to A.A.C.
Number; -
ARIZONA DE ARMEE:NT OF WATER RESOURCES
••
1111
44til, , At if if
•
REVISE
„ . -
MAY x9.417_008 •
1 0 I
. • • M.00.80:1115

Maricopa County
Planning & Development Department
William Haas, P.E.
Planning &Development
501 North 446 Street, Suite 200 Date: August 18, 2008
Phoenix, Arizona 85008
Phone: (602) 372-4114
Fax: (602) 506-8762 Memo To: Darren Gerard, Deputy Director, Department of Planning 8z.
email www.maricopa address: goy/planning Development
WilliamHaas@mail maricopasmv
Attn: Robert Kuhfuss, AICP, Senior Planner, Project Management Division
From: William Haas, Drainage Engineering Supervisor, Planning and
Development
Subject: B200603115, Arroyo Norte Improvement Plans
The plans and reports submitted 8/14/08 for permit # B200603115 have been
reviewed and the following comments require resolution. Please note that all
comments are typical only due to the compressed timeframe for the review. The
engineer must evaluate all comments as they pertain to other portions of the design
not specifically mentioned in this review. The associated Final Plat, S2006015, was
not submitted concurrent with this latest review and is not recommended for approval
by the Board of Supervisors.
Drainage Report
1. As noted in the previous review comments, the design of bleed-off systems
should conform to standard 6.10.10 of the County standards manual. This
section identifies that "the maximum bleed-off rate should typically not
exceed 1 cfs." The engineer has identified an average rate of 1.5 cfs for basin
B west + B central and 2.26 cfs for basin A. Correct the design to meet the
standard.
2. The outfall of retention basin in Tract C (B central) is listed a 1905.84. The
contours show the existing grade as greater than 1910. How can this be
physically installed without grading into the restricted NAOS area? Verify and
correct the design.
3. The adjacent water surface elevation for Tract C is 1911+, as shown on the
plans. Placing a bleed-off pipe at this location has the effect of bring off-site
storm water into the basin through the pipe. Correct the design.
4. As previously requested, it is required that the engineer provide a discussion
on modeling analysis and parameter selection. The calculation of the bleed-off
rate uses the orifice equation without providing any discussion. Several
discrepancies are noted in the modeling.
a. The flow coefficient is selected as 0.6. This is applicable for smooth
edged openings. However, for rough-edged opening, as might be cut
by a contractor in the field using a torch or other means, 0.4 is

recommended. Why is 0.6 selected? The engineer has not provided any
construction specifications on the plans that would dictate a smooth-
edged opening. Discuss and justify the parameter selection in
conformance with the design.
b. The average headwater depth for basin A is given as 1.13 feet for a 9
inch orifice opening. This can be assumed to be half the basin depth of
3 feet minus the opening height (2.25/2 = 1.125 feet). However, for
free flowing outlet conditions, as should be the design, the headwater
depth is measured from the center of the orifice opening. Correct the
modeling.
c. The analysis utilizes an average flow rate calculated at the average
depth. However, the orifice equation is exponential and not linear. The
average flow rate will not occur at the average depth. The County
standards manual in section 6.10.10 dictate the use of the Modified
Puls storage routing method (as utilized by Hec-1) to facilitate design
to address this specific issue. Correct the modeling.
5. The HEC-1 model identifies that retention in basin 6 is based upon mass
grading and not the 100-year 2-hour requirement. As the mass grading is not
currently approved this is inappropriate. There are no restrictions upon this
basin that would require that the excess volume be maintained. Either place
such restrictions through plat notes or revise the modeling to reflect regulatory
required storage.
6. The }{EC-1 developed conditions model appear to have basin B identified as
basins 1 and 2 in the provided DEI map (figure 3). The model identifies that a
25 foot weir is assumed while a 30 foot weir is designed. Correct this
discrepancy and the modeling.
7. The report identifies that wash A has a existing condition flow of 2,523 cfs
and post development flow rate of 2,159 cfs. The models identify that the
flow rate is 2,528 at C7A5c and 2,519 at C75Ac8. These rates are shown on
figures 3 and 4. Correct these, and all other, typographical errors.
8. Table 6 shows the drainage area for Basin B as 30.02 ac which equals 0.469
sq. mi. Basins 7A5h1 and 7A5h2 have a combined area of .0413 sq. mi or
26.43 ac. Additionally the volume modeled does not match the volume
provided as shown in table 6 or appendix B. Explain why this modeling does
not reflect the design.
9. As previously noted, the HEC-1 analysis used to evaluate the pre and post
construction hydrology for the site utilizes a minimum time step of 5 minutes
for calculations. For the most of the identified routings, this is longer than is
appropriate for the physical length of the route at the identified velocities. This
artificially attenuates the peak flow at the end of the route. In conjunction with
the proposed bleed of system, this may represent an adverse impact to down
stream properties in violation of the Drainage Regulation. The engineer's
response in the August 13 HRC memo is not accurate. Any time that a routing
time, as represented by the NSTPS and TMIN, models a time greater than

•
what is physically present, it artificially moves the hydrograph. As previously
requested, revise the modeling to accurately reflect and model the watercourse
geometry.
10. As noted in previous reviews, the Froude number for artificial channels should
be maintained below 0.86. Wash A is not in conformance with this standard at
several sections. The engineer's response in the August 13 HRC memo is not
accurate nor is the analysis mentioned provided in this report.
a. Reducing the Froude number in some sections is not a justification for
increasing it at other sections.
b. Based on modeling performed by County staff utilizing the IIRC
modeling provided; when additional conveyance is added, the model
does calculate the Froude number as stated by the engineer. However,
the warnings generated by the model indicate that the model is not
properly resolving the equations and defaulting to a base parameter.
When additional cross sections are added, as recommended by the
HEC-RAS user's manual, the equation is properly resolved and the
channel hydraulic characteristics meet County standards. Therefore, a
reduction in the encroachment limit on wash A is warranted. Verify
and revise the design accordingly.
Sincerely,
William Haas, P.E.