HomeMy WebLinkAbout11 TUSTIN LEGACY RMP 01-03-05
AGENDA REPORT
Agenda Item 11
Reviewed:
City Manager -
Finance Director N/A
MEETING DATE: JANUARY 3, 2005
TO: WILLIAM A. HUSTON, CITY MANAGER
FROM: PUBLIC WORKS DEPARTMENT/ENGINEERING DIVISION
SUBJECT: APPROVAL OF THE TUSTIN lEGACY RUNOFF MANAGEMENT PLAN (RMP)
(CIP No. 5025)
SUMMARY
The Tustin legacy Runoff Management Plan (RMP) outlines a plan to provide flood protection for the
Tustin legacy Development site through identification of appropriate backbone infrastructure needed
to mitigate development runoff. This document was initiated due to a requirement of the
Environmental Impact Statement/Environmental Impact Report (EIS/EIR) for the former Marine Corps
Air Station (MCAS) Tustin and the Cooperative Agreement No. D02-119 between the City of Tustin
and the Orange County Flood Control District. The RMP is now complete and ready for approval by
the City Council.
RECOMMENDATION
It is recommended that the City Council approve the Final Tustin legacy Runoff Management Plan,
dated December 2004, and direct staff to forward notification of this approval to the Orange County
Flood Control District.
FISCAL IMPACT
None.
BACKGROUND AND DISCUSSION
The Tustin legacy RMP is intended to provide guidelines to be followed for the design and
implementation of on-site backbone storm drain systems and adjacent regional flood control channel
improvements (Barranca Channel and Peters Canyon Channel) in conjunction with development of
the Tustin legacy site. The RMP identifies existing watershed conditions, evaluates impacts of
proposed development, and recommends necessary backbone infrastructure to mitigate the
proposed development runoff. Water quality protection measures are also addressed to ensure
consistency with the City's Municipal National Pollutant Discharge Elimination System permit and the
County's Drainage Area Management Plan.
Approval of the Tustin Legacy RMP
January 3, 2005
Page 2
The RMP satisfies a portion of Cooperative Agreement No. D02-119 which specifies development
conditions and requirements for the improvement of Barranca Channel and a portion of Peters
Canyon Channel adjacent to the Tustin Legacy Development. Specifically, this agreement includes a
requirement for the development of a Runoff Management Plan/Engineering Study for the Tustin
Legacy site. The RMP also satisfies the EIS/EIR requirement for a drainage study to ensure there
will be no worsening of existing drainage conditions to storm drain facilities within and adjacent to the
project site. Implementation of appropriate interim and ultimate flood control infrastructure is also
addressed in the RMP as required in the EIS/EIR.
Attached is the Introduction (Section 1) to the RMP. The full version of the RMP is available for
review at the City Clerk's Office.
The Orange County Flood Control District received the City's final submittal of the RMP on December
22, 2004. The Flood Control District has indicated their intent to issue an approval letter for the RMP
relative to regional flood control issues. If not received by the January 3rd City Council Meeting, the
letter should be issued shortly thereafter.
Tim D. Serlet
Director of Public Works/City Engineer
Dana R. Kasdan
Engineering Services Manager
TDS: DRK: ccg: Approval of Tustin Legacy Runoff Mgmt Plan.doc
Attachments: Tustin Legacy Runoff Management Plan (RMP) -Introduction (Section 1)
Location Map
TUSTIN LEGACY
FINAL
RUNOFF MANAGEMENT PLAN
Prepared By:
~
C[JNSULTING
14725 Alton Pkwy
Irvine, CA 92618
Project Manager:
Proj.ct Eo,;o",g-ß-
Tom Ryan, . .
Approved BY:C!- Q ~
Tim Serlet, City Engin
City of Tustin
December 22, 2004
Table of Contents
SECTION 1 -INTRODUCTION............................................................................................... 1-1
1.1 DESCRIPTION OF STUDY AREA............................................................................ 1-1
1.2 BACKGROUND........................................................................................................1-1
1.3 OBJECTIVES ...........................................................................................................1-2
SECTION 2 - EXISTING WATERSHED AND FLOOD PROTECTION ASSESSMENT........... 2-1
2.1 WATERSHED DESCRIPTION......................................................"""""""""""""" 2-1
2.2 PREVIOUS STUDIES............................................................................................... 2-1
2.3 FLOODPLAIN MAPPING..........................................................................................2-2
SECTION 3 - REGULATORY REQUIREMENTS AND DESIGN CRITERIA............................ 3-1
3.1 FLOOD PROTECTION REQUIREMENTS................................................................ 3-1
3.2 HYDROLOGY AND HYDRAULIC DESIGN .............................................................. 3-1
3.3 ENVIRONMENTAL PERMITTING ............................................................................ 3-2
SECTION 4 - WATERSHED MODELING AND MASTERPLAN DEVELOPMENT .................. 4-1
4.1 PROCEDURE METHODOLOGY.............................................................................. 4-1
4.1.1 Rational Method ................................................................................................ 4-1
4.1.2 Unit Hydrograph (UH) ........................................................................................ 4-2
4.1.3 Detention Basin Routing Analysis """"""""""""""""""""""""""""""""""" 4-2
4.1.4 Storm Drain Hydraulics...................................................................................... 4-3
4.1.5 Regional Channel Hydraulics............................................................................. 4-4
4.2 EXISTING CONDITION............................................................................................4-4
4.2.1 Land Use and Soil """""""""""""""""""""""""""""""""""""""""""""'" 4-4
4.2.2 Drainage Features.............................................................................................4-4
4.2.3 Existing Condition Hydrology............................................................................. 4-6
4.3 DEVELOPED CONDITIONS """""""""""""""""""""""""""""""""""""..........4-7
4.3.1 Land Use """""""""""""""""""""""""""""""""""""""'"..........................4-7
4.3.2 Drainage Features............................................................................................. 4-9
4.3.3 Developed Condition Hydrology......................................................................... 4-9
Notes 1. Discharges do not include detention basin retention. ............................................4-11
4.3.4 Barranca Channel Drainage Area Hydrology Analysis ......................................4-11
SECTION 5 -IMPACTS OF PLANNED DEVELOPMENT....................................................... 5-1
5.1 DRAINAGE AREA COMPARISON ........................................................................... 5-1
5.2 STORM RUNOFF COMPARISON AND IMPACTS................................................... 5-1
5.3 DEVELOPED CONDITION EXCESS RUNOFF MITIGATION .................................. 5-3
SECTION 6 - REGIONAL CHANNEL IMPROVEMENTS........................................................ 6-1
6.1 IMPACTS ON EXISTING CHANNELS...................................................................... 6-1
6.2 BARRANCA CHANNEL.................................................................""""""""""""'" 6-1
6.2.1 Existing Conditions ............................................................................................6-1
6.2.2 Hydraulic Design of Channel Improvements ...................................................... 6-2
6.2.3 Recommended Channel Improvements............................................ """""""'" 6-4
6.2.4 Results """""""""""""""""""""""""""""""""""""'""""""""""""""""'" 6-5
6.3 PETERS CANYON CHANNEL ................................................................................. 6-7
6.3.1 Existing Conditions """"""""""""""""..................................................."....... 6-7
6.3.2 Hydraulic Design of Channel Improvements ...................................................... 6-8
6.3.3 Recommended Channel Improvements................................................. ...........6-14
6.3.4 Results """"""""""""""""""""""""""""""""""""""'"..............................6-15
6.4 SANTA ANA-SANTA FE CHANNEL........................................................................6-17
6.4.1 Existing Conditions """"""""""""""""""""""""""""""""""""".................6-17
6.4.2 Recommended Channel Improvements................................................ ............6-18
SECTION 7 - URBAN RUNOFF WATER QUALITY PROTECTION MEASURES ................... 7-1
7.1 EXISTING REGULATORY CONTROLS ON URBAN RUNOFF................................ 7-1
7.1.1 Pollution Prevention Measures (Non-Structural BMPs)...................................... 7-1
7.1.2 Structural Source Control BMPs ........................................................................ 7-2
7.1.3 Site Design BMPs.............................................................................................. 7-3
7.1.4 Treatment Control BMPs ................................................................................... 7-3
7.1.5 Water Quality Enforcement................................................................................ 7-4
7.2 REGULATORY CONTROLS IN CONSTRUCTION .................................................. 7-5
7.2.1 Sediment, Erosion, and Pollution Control........................................................... 7-5
7.2.2 Stomnwater Pollution Prevention Plan (SWPPP)................................................ 7-8
SECTION 8 - ESTIMATED CONSTRUCTION COSTS........................................................... 8-1
8.1 Standard Construction Elements .............................................................................. 8-1
8.2 Unit Construction Costs ............................................................................................ 8-1
8.3 Preliminary Estimate of Construction Costs .............................................................. 8-3
SECTION 9 - IMPLEMENTATION AND FACILITY PHASING ................................................ 9-1
9.1 IMPLEMENTATION MEASURES............................................................................. 9-1
9.2 PHASED CONSTRUCTION ........................,............................................................ 9-1
9.3 DEVELOPMENT OF FINAL DRAINAGE DESIGN REQUIREMENTS AND
GUIDELINES .............................................................................................,........................ 9-3
9.3.1 Minimum Submittal Requirements ..................................................................... 9-3
9.3.2 Final Design Requirements................................................................................ 9-3
9.3.3 Local Drainage Facilities.................................................................................... 9-5
9.3.4 Design Standards .............................................................................................. 9-6
SECTION 10 - REFERENCES ..............................................................................................10-1
Tables
Table No. 3.1 - Proposed Flood Control Facility Design Criteria Guidelines ........................... 3-2
Table No. 3.2 - Environmental Permit Summary .................................................................... 3-3
Table No. 4.1 - Existing Condition Rational Method Hydrology Peak Discharges to Regional
Facilities..................................................................................................................................4-6
Table No. 4.2 - Summary of Specific Plan Land Uses ............................................................4-7
Table No. 4.3 - Developed Condition Rational Method Hydrology Peak Discharges to Regional
Facilities (Unmitigated Condition)...........................................................................................4-11
Table No. 4.4 - Barranca Channel100-year Expected Value Discharge Summary ...............4-13
Table No. 5.1 -100-Year Stomn Runoff Comparisons ............................................................5-1
Table No. 5.2 - Peak Flow Mitigation for Areas Tributary to Barranca Channel...................... 5-4
Table No. 6.1 - Barranca Channel (Facility No. F09) Design Discharges ............................... 6-3
Table No. 6.2 - Manning's Roughness Coefficients for Barranca Channel............................. 6-3
Table No. 6.3 - Barranca Channel (Facility No. F09) Discharge Comparison ......................... 6-6
Table No. 6.4 - Summary of Proposed Barranca Channel Hydraulics """""""""""""""""" 6-6
Table No. 6.6 - Manning's Roughness Coefficients for Peters Canyon Channel ...................6-10
Table No. 6.7 - Existing Peters Canyon Channel Bridge Configurations................................6-11
Table No. 6.8 - Comparison of Existing and Project Hydraulics for Peters Canyon Channel.6-15
Table No. 6.9 - Summary of Proposed Peters Canyon Channel Hydraulics ..........................6-16
Table No. 6.10 - Summary of Proposed Peters Canyon Channel Hydraulics ........................6-16
Table No. 8.1 - Summary of Construction Unit Costs .............................................................8-2
Table No. 8.2 - Summary for Drainage Construction Costs.................................................... 8-3
Table No. 8.3 - Total Construction Cost by Watershed Area .................................................. 8-4
List of Figures
Figure 1.1 - Regional Vicinity Map
Figure 1.2 - Site Vicinity
Figure 2.1 - Flood Zone Map
Figure 4.1 - Watershed Boundary Map
Figure 4.2 - Land Use Map
Figure 4.3 - Proposed Storm Drain System
Figure 6.1 - Peters Canyon Channel Grade Line Change from Survey Data
Figure 9.1 - Master Development Footprint
List of Exhibits
Exhibit A - Onsite Existing Conditions Hydrology Map
Exhibit B - Onsite Developed Conditions Hydrology Map
Exhibit C - Barranca Channel Plan & Profile Sheets
Exhibit D - Peters Canyon Plan & Profile Sheets
Exhibit E - Barranca Channel Watershed, Existing Condition Hydrology Map
Exhibit F - Barranca Channel Watershed, Deveioped Condition Hydrology Map
Exhibit G - Barranca Channel Watershed, Developed Condition Complex Hydrology Map
iii
Tustin Legacy
Final Runoff Management Plan
Issue Date: 22-Dec-2004
SECTION 1 - INTRODUCTION
The purpose of the report is to document existing watershed conditions and outline a plan to
mitigate development runoff through appropriate backbone infrastructure to afford flood
protection for the Tustin Legacy Development site. This runoff management plan (RMP)
identifies the recommended backbone infrastructure to intercept and convey both regional and
local storm water runoff from the Tustin Legacy Development site. The recommendations are
based on the most current infomnation for the project watershed, including approved land uses
and preliminary engineering studies within the development area.
1.1
DESCRIPTION OF STUDY AREA
The proposed development area is located within the cities of Tustin and Irvine, Orange County.
The portion located within the City of Tustin is the Tustin Legacy Development. An approximate
94-acre portion of proposed development area bounded by Barranca Parkway, to the south,
Peters Canyon Wash, to the west, Harvard Avenue, to the east, and just north of Wamer
Avenue, to the north, is located within the City of Irvine. For the purpose of this RMP, both
developments will be referred to from this point as Tustin Legacy Development. The boundaries
of the Tustin Legacy site are shown on Figure 1.1 and Figure 1.2. The Tustin Legacy project
site is tributary to two sub-watersheds: the Barranca Channel watershed and the Peters Canyon
Channel watershed. Both of these sub-watershed are tributary to the San Diego Creek
watershed. The Peters Canyon Channel watershed drains a tributary area of approximately 46
square miles, and extends a total distance of 8 miles from the headwaters in the Santa Ana
Mountain foothills to the junction with San Diego Creek. Peters Canyon Channel runs
southwest through the eastern portion of the Tustin Legacy site.
The Barranca Channel watershed extends approximately 4.5 miles and drains a tributary area
of 2.2 square miles. It extends from the Edinger Avenue/SR-55 interchange south to the
confluence with San Diego Creek. The Barranca Channel flows along the southerly border of
the proposed Tustin Legacy project site.
The proposed development will consist of single-family residences, condominiums, commercial
development, a golf course, and educational land uses.
1.2
BACKGROUND
The Tustin Legacy Development site is located on a former Marine Corps Air Station that was
selected for closure in 1991. The site was originally constructed by the Navy to serve as a Navy
lighter-than-air (L T A) base to support the World War II efforts. In 1949 the L T A was
decommissioned as an active facility. In 1951, the base was reactivated as the MCAS to
support the Korean War efforts. A large portion of the MCAS was annexed to the City of Tustin
in 1976, with approximately 94 acres of the MCAS within the City of Irvine.
Pursuant to The Defense Base Cleanup and Realignment Act of 1990, the federal government
decided to close the Marine Corp Air Station in 1991. After the announcement of the closure in
1991, in 1992 the City of Tustin was designated by the Department of Defense as the lead
redevelopment authority (LRA) for reuse planning and the City immediately initiated work on
RBF Consulting
1-1
Tustin Legacy
Final Runoff Management Plan
Issue Date: 22-Dec-2004
planning for reuse of MCAS using funding sources from the City, Marine Corps and Department
of Defense Office of Economic Adjustment Resources.
The MCAS Tustin Reuse Plan developed, in accordance with the Base Closure Law, was
adopted by the City Council of the City of Tustin on October 17, 1996 and amended in
September 1998. On January 16, 2001, a final joint Environmental Impact
Statement/Environmental Impact Report (final EIS/EIR) for the disposal and reuse of MCAS
Tustin as well as the Mitigation Monitoring and Reporting Program for the final EIS/EIR were
adopted by the City. In March 2001, a Record of Decision was issued by the Department of the
Navy and appears in the final EIS/EIR Reuse Plan. On February 3, 2003 the city approved and
adopted the MCAS Tustin Specific Plan by ordinance 1257 setting forth the zoning and
entitlement framework for future development of Tustin Legacy site within the City of Tustin.
The Specific Plan conforms to and implements the Reuse Plan as well as the Tustin General
Plan. Development within the City of Irvine will require separate zoning entitlements within that
jurisdiction.
In March of 2003, the City of Tustin entered into a Cooperative Agreement with the Orange
County Flood Control District (OCFCD) and County of Orange for the improvement of regional
drainage facilities through the Tustin Legacy site. The Cooperative Agreement, 002-119,
identified conditions for the development of the site, and the improvement of the Barranca
Channel and a portion of Peters Canyon Channel that transverses the Tustin Legacy
development. Specifically, this agreement includes a requirement for the development of a
Runoff Management Plan/Engineering Study for the Tustin Legacy site. The City and the
County of Orange have subsequently approved Amendment No.1 to Joint Cooperative
Agreement D02-119. The amendment includes provisions for the construction of additional
improvements to the Peters Canyon Channel, and milestones to the implementation of the
channel improvements.
1.3
OBJECTIVES
This Runoff Management Plan for the Tustin Legacy development site was prepared to:
Provide guidelines to be followed for the design and implementation of flood control
improvements for the site development.
Describe existing regulatory controls for urban runoff for new development.
The RMP is to adhere to the requirements outlined in the Cooperative Agreement D02-119 and
Amendment No.1, between the City of Tustin, the Orange County Flood Control District and the
County of Orange and the requirements set forth in the MCAS Reuse FEIR/FEIS. The purpose
of the Cooperative Agreement was to establish the temns and conditions, under which the
regional fiood control channel improvements identified in the FEIS/FEIR for the disposal and
reuse of MCAS Tustin, will be scheduled, engineered, financed, constructed, operated and
maintained.
RBF Consulting
1-2
ø Master Developer Boundary
WATERSHED BOUNDARIES
- Tributary to Peters Canyon Wash
- Tributary to Barranca Channel
~ I ~,:,:~~~::e
TUSTIN MCAS ROMP
Master Development Footprint
Figure 9.1