San Bernardino SOSEO8 Los Angeles County County

Riverside Villa County Park Reservoir

Orange

Project Orange County

Pacific Ocean H

a n d Orrange y S C a re n e ti Miles k a g o 0 8 C an Irvine ntiago Cree k 241 yo Sa n Rd Regional Legend Park

Stream Gauge Selected Streams Santiago Hills II: Cha East Orange Area 1: pm Stage 2 J a Selected Roads a n Stage 3 m A v e b n o u Water Bodies re e e R d Regional Park

County Boundary

City Boundary PCR SHII: Stage 1 Irvine Lake

SHII: Stage 2

East Orange Area 1: Stage 3 Santiago Hills II:

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s

a Stage 1

W

n o Tusttiin Footthiilllls y n a C rs te S e an P tia Can go yon Rd Figure 2-1 261 241 Santiago Hills II and East Orange Area 1: Project Location Map Tusttiin

(Roads and water bodies provided by RBF Consulting)

Feet May 2005 GeoSyntec 0 2,250 4,500 P:\GIS\Irvine\SHii\projects\May(05)\SantiagoHillsII(Fig_2-1).mxd Consultants Stage 1 Stage 2 Ultimate Conditions

Irvine Irvine Irvine Regional Regional Regional Park Park Park ntiago tia Sa Cree Santiago Cr San go C k eek reek

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a J J

a a m

m m b

b b o o r o e 1 r 1 r 1 4 e 4 e 4 e 2 e 2 e 2 R R R R S R S R S d d d

PCR PCR PCR Irvine Lake Irvine Lake Irvine Lake 61 61 1 2 2 26 R R R S S S

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s h h

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a a W W W n S n n o an o Sa o Sa y tia go Can y ntia y nti n yon Rd n go Canyon Rd n a go Canyon R a a a d C C C rs rs rs te te e e S e S et S P R P R P R 2 2 2 4 4 4 1 1 1

Feet 0 3,000 6,000

Legend Figure 2-2 Land Uses Santiago Hills II and East Orange Area 1: Major Streams Single Family Residential Park Land Use Delineations for Stage 1, Stage 2 Improved Conveyance Multi Family Residential Open Space and Ultimate Conditions Water Bodies School Future Development Irvine Regional Park Road (Water bodies, and land use delineations provided by RBF Consulting) Prepared by The Irvine Company for GeoSyntec May 2005 Consultants P:\GIS\Irvine\SHII\projects\May(05)\SantiagoHillsII(Fig_2-2).mxd Consideration by the City of Orange S

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t i a g o C a n y o n R Irvine d Santiago C Regional reek Park D 1 24 R S anyon C E t C reek on T m H C re a - F C 7 n E d ha y pm C a T C J n E a - r A T e m v B 6 e b en C o k u - C r e 9 e Black Willow e R Forest d Lacustrine North Area Tributary

PCR A Irvine Lake So T u ri th bu ta ry h s a W n o y

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2

6

1 Canyo go n R ntia d ry Sa buta ri T S s R ' E y 2 d 4 1 o o W

Lower Peters Canyon Retention Basin

Feet 0 2,250 4,500

Legend Existing Subwatershed Areas Selected Roads Area A Ephemeral Tributary Figure 2-3 Intermittent Tributary Area B Santiago Hills II and East Orange Area 1: Major Streams Area C Existing Subwatershed Areas and Natural Tributaries Improved Conveyance Area D Water Bodies Area E Lower Peters Canyon Retention Basin (Roads, water bodies, and subwatershed delineations provided by RBF Consulting) Irvine Regional Park Black Willow Forrest Lacustrine Area Prepared by The Irvine Company for GeoSyntec May 2005 Consideration by the City of Orange Consultants

P:\GIS\Irvine\SHII\projects\May(05)\SantiagoHillsII(Fig_2-3).mxd S

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t i a g o C a n y o n

R antiag d S o Cree Irvine k Regional

Park 1 24 R S yo t Can n Creek on m H C re h F a ap B n m d Drainage 4 an y A C J v a e r n e m u e b e D k o r e Drainage 5 e R d

Drainage 3 C

Drainage 6

PCR Drainage 3 Drainage 1 Irvine Lake Drainage 2

h A s a W n o y Drainage 7 n

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6 1 o Canyon iag Rd Sant

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2 4 E 1

Lower Peters Canyon Retention Basin

Feet 0 2,250 4,500

Legend Proposed Subwatershed Areas Selected Roads Area A Major Streams Area B Figure 2-4 Improved Conveyance Area C Santiago Hills II and East Orange Area 1: Water Bodies Area D Subwatershed Areas and Drainage Areas- Ultimate Conditions Drainage Boundary Area E Lower Peters Canyon Retention Basin (Roads, water bodies, and subwatershed delineations Irvine Regional Park provided by RBF Consulting)

Prepared by The Irvine Company for GeoSyntec May 2005 Consultants P:\GIS\Irvine\SHII\projects\May(05)\SantiagoHillsII(Fig_2-4).mxd Consideration by the City of Orange Weir Canyon

Fremont Blind Canyon Canyon

Black Star Canyon Handy Santiago Creek Creek

Ladd Baker Canyon Canyon

Silverado Limestone Canyon Canyon Williams Canyon Harding Canyon

Santiago Creek Watershed

Figure 2-5 Santiago Creek Watershed and Subwatersheds (Source: http://www.ocwatersheds.com/watersheds/santaana_santiago_subwatershed.asp)

Prepared by The Irvine Company for GeoSyntec May 2005 Consideration by the City of Orange Consultants ek go Cre ntia Sa Irvine 6A2 Regional Park

1 24 6A1 R S

G1

G2 J

G3 C8 6D2 C2 E 2A

F2 6D1

2B

C1 PCR B1

A1

HR1

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2 6G

6 1 S ant iago Cany on Rd

S R 2 4 1

Legend Hydrodynamic Separator System (HSS) Treatment Swale Selected Roads Major Streams Extended Detention Basin Emergent Marsh Irvine Regional Park Water Body Feet 0 625 1,250 2,500 Nutrient Source Control Areas (Fertilizer Application Reduction) Non-Impact Open Space (Tributary to Emergent Marshes) Preserved Open Space Areas Treated By: Figure 5-1 Hydrodynamic Separator System Santiago Hills II and East Orange Area 1: Extended Detention Tributary Areas to Treatment System and Locations for Treatment Control PDFs Extended Detention, Hydrodynamic Separator System Treatment Swale, Hydrodynamic Separator System (Roads, water bodies, and BMP Locations Extended Detention, Treatment Swale provided by RBF Consulting) Extended Detention, Hydrodynamic Separator System, Bioretention Prepared by The Irvine Company for GeoSyntec Extended Detention, Bioretention May 2005 Consideration by the City of Orange Consultants

P:\GIS\Irvine\SHII\projects\May(05)\SantiagoHillsII(Fig_5-1).mxd S

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6A2

2A

C 2B HAPMAN AVENUE 6A1

C2 G1

C3 C1

VS G2 -G 1

C8

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G3 6 1

4 F2 -C C4 VS

E J AM C5

BO S

R V Feet E S R

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0 375 750 S B1 S R - 2 O C 2 A 5 4 D 1 Legend B2 Hydrodynamic Separator System (HSS) Land Use C6 B3 Streams Multi Family HR1 B4 C7 6 Flow Path Park V S-C Water Body Road Catchment Boundary School Subwatershed Boundary Single Family VS-B3 VS-B4 Areas Treated with Bioretention Open Space From Extended Treatment or Conveyance Swales A2 Detention Basin VS HR1 Extended Detention Basin -A2

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Emergent Marsh S

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1

A1 Figure 5-2 Santiago Hills II and East Orange Area 1: Peters Proposed Treatment Systems for Areas Canyon Tributary to PCR Reservoir

(Roads, water bodies, grading plan and BMP locations provided by RBF Consulting)

Mary 2005 GeoSyntec P:\GIS\Irvine\SHii\projects\May(05)\SantiagoHillsII(Fig_5-2).mxd Consultants Plan View

Max Elevation of Extended Detention Pool

Forebay

Inflow Vegetated Low Flow Channel

Outflow

Maintenance Access Rd

Profile

Influent Pipe

WQ Elevation Riser Pipe

Forebay

Figure 5-3 Conceptual Illustration of an Extended Detention Basin (Adapted from CA BMP Handbook, 2003)

GeoSyntec May 2005 Consultants Plan View

Diversion Weir High Flows Over Weir Weir Box

Inlet Outlet

Separation Screen

Profile High Flow Bypass

Inlet Outlet

Separation Screen

Figure 5-4 Conceptual Illustration of a Typical Hydrodynamic Separator System (schematic by CDS Technologies) GeoSyntec May 2005 Consultants Plan View

Energy Dissipater Inlet Side Slope: 4H :1V or less

Outlet Roadway

Check dam Bottom Slope: 2- 6% if bottom slope exceeds 4% Flow Spreader

Profile 6” Min Topsoil Roadway Grass height exceeds water quality design flow by 2”

Flood Flow Depth Water Quality Depth

6” Freeboard 1 Shoulder 4

Swale Vegetation: Small plants, tall grasses and shrubs Swale Width (recommended 3ft,channel divider if >10ft)

Figure 5-5 Conceptual Illustration of a Treatment Swale (Adapted from CA BMP Handbook, 2003) GeoSyntec May 2005 Consultants Plan View

Parking Lot Sheet Flow

Curb Stops

Stone Diaphragm Grass Filter Strip

Optional Sand Layer

Outlet

Gravel Curtain Drain Overflow Underdrain Collection System

Profile

Curb Stop Stone Diaphragm Gravel Curtain Drain

Optional Sand Filter Layer

Underdrain

Figure 5-6 Conceptual Illustration of a Bioretention Facility (Adapted from CA BMP Handbook, 2003) GeoSyntec May 2005 Consultants

Portland, Oregon Chino, California

Chino, California Chino, California

Figure 5-7 Examples of Bioretention Facilities

GeoSyntec May 2005 Consultants

533

532

531

530

529

528 water surface elevation (ft) elevation surface water

527

526

525 1/1/2002 3/6/2002 5/9/2002 7/12/2002 9/14/2002 11/17/2002 1/20/2003 3/25/2003 5/28/2003 7/31/2003 10/3/2003

Existing Condition Project condition

Figure 7-1 Peters Canyon Reservoir Modeled Water Surface Elevation Source: Flow Science (8/30/04)

GeoSyntec May 2005 Consultants eek Cr 6A go 6A2 tia an S

1 24 6A1 R S

G1 6A2 G1 G2 G2 J

G3 F2 6A1 G3 E 6D2 C8 2A E 6D2 2A C5 C2 C4 C7 C3 C6 6D1

C1 2B J SWALE B4 S2 A2 B1 S2 6D1 PCR B1 2B

A1 S1

A1

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n B3 o y HR1 n a C

s r e t e 6G P

HR1

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1 San tiago Cany on Rd

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Feet 0 625 1,250 2,500

Legend Soil Texture Hydrodynamic Separator System Clay Treatment Swale Clay Loam Gravely Loam Figure C-1 Major Streams Loam Santiago Hills II and East Orange Area 1: Improved Conveyance Loamy Sand Soil Texture Map Selected Roads Outcrop Water Body Sand (Roads, water bodies, and BMP Locations Sandy Loam provided by RBF Consulting) Extended Detention Basin Silt Loam Emergent Marsh A1 Catchment Boundary Prepared by The Irvine Company for GeoSyntec May 2005 Consideration by the City of Orange Consultants

P:\GIS\Irvine\SHII\projects\May(05)\SantiagoHillsII(Fig_C-1).mxd