HomeMy WebLinkAboutUpper Etiwanda/San Sevaine Watersheds 4
SUMMARY REPORT
UPPER ETIWANDA /SAN SEVAINE WATERSHEDS
ALTERNATIVES FOR FLOOD CONTROL AND WATER CONSERVATION
PREPARED FOR
THE ETIWANDA NORTH LAND OWNERS CONSORTIUM
THE CARYN COMPANY
July 1990
PREPARED BY
FUSCOE, WILLIAMS, LINDGREN & SHORT, INC.
11651 Sterling Avenue
Riverside, CA 92503
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Submitted By: b/30/3
erdt"d J. Bari!, P.E. -
OF C Ate'
SUMMARY REPORT
UPPER ETIWANDA/SAN SEVAINE WATERSHEDS
ALTERNATIVES FOR FLOOD CONTROL AND WATER CONSERVATION
TABLE OF CONTENTS
PAGE
PREFACE P -1
FOREWORD F -
EXECUTIVE SUMMARY E -1
SECTION 1 - INTRODUCTION
1.1 General . 1 -1
1.2 Upper Etiwanda Watershed 1 -2
1.3 Upper San Sevaine Watershed 1 -2
SECTION 2 - PROJECT ISSUES
2.1 FEMA Clearance 2 -1
2.2 Etiwanda Creek Runoff Mitigation 2 -2
2.3 Water Conservation 2 -3
2.4 Financial Plan, Use of Floodway Properties 2-4
2.5 Environmental Mitigation Plan 2 -11
SECTION 3 - PROJECT ALTERNATIVES INVESTIGATED
3.1 Etiwanda Creek Channel Facilities 3 -1
3.1.1 Existing Concrete Channel 3 -2
3.1.2 Alternative Channel Facilities 3 -2
• Rectangular Concrete Channel - Limited Velocity 3-4
• Rectangular Concrete Channel - High Velocity 3 -5
• Parabolic Armorflex Lined Channel 3-6
• Levee System 3 -7
3.2 Etiwanda Creek Debris Facilities 3 -8
• Debris Basin at Canyon Mouth 3 -10
• Debris Dam at Canyon Mouth 3 -11
• Dual Debris/Detention Dam Facility at Wilson Avenue 3 -12
• Dual Debris/Detention Facilities with a Basin at Canyon 3 -13
Mouth and Dam at Wilson Avenue
PAGE
3.3 Etiwanda North Runoff Mitigation Detention Facilities 3 -14
3.3.1 Diversion to San Sevaine Basin No. 5 3 -14
• Expand and Combine Basins 4 & 5 with Intex Parcel 3 -16
• Combine Basins 2 & 3 and Expand Basins 4 & 5 - 3 -17
without Intex Parcel
3.3.2 Etiwanda Spreading Grounds 3 -18
• All Detention North of Wilson Avenue - on Mainstem 3 -20
• All Detention North of Wilson Avenue - off Mainstem 3 -21
• All Detention South of Wilson Avenue - off Mainstem 3 -22
• Detention North and South of Wilson Avenue - 3 -23
off Mainstem
3.4 Water Conservation Facilities 3 -24
• San Sevaine Basins 3 -32
• .Etiwanda Spreading Grounds 3 -33
3.5 Project Area Map
SECTION 4 - CATEGORICAL PROJECT SOLUTIONS
4.1 SBCFCD 1983 Master Plan Solution 4 -1
4.2 Modified SBCFCD 1983 Master Plan Solution 4 -2
4.3 Environmental Levee Solution 4 -3
4.4 Composite Concrete /Armorflex Channel Solution 4-4
4.5 All Armorflex Channel Solution 4 -5
4.6 Project Solution Matrix
4.7 Schematic Plans
d
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PREFACE
Todays leaders are acutely conscious of the need to preserve and protect our environment. Earthday
1990 was a testimony to this awareness as millions of people around the world made a clear statement -
it has become socially unacceptable to harm the environment.
Master planning of communities has become a means of providing a good balance between the
environmental, social, aesthetic, quality, technical, and economic issues of today and the future, while
providing the necessary housing for our growing population. The proposed Etiwanda North development
is no exception. The land, engineering, and resource planning for Etiwanda North has made every
effort to integrate the environment with the development.
Engineering planning has studied the necessary infrastructure for water related facilities. Included are
flood control and water conservation facilities consisting of channels or levees, debris basins, detention
basins, and water percolation areas.
The engineering planning for these facilities has focused on examining the many potential solutions
relative to their environmental impact, ability to obtain necessary permits, flood protection provided,
aesthetic values, cost, and acceptability for operation and maintenance by a public agency. To that end,
this report is intended to present those solutions and the facts for independent judgement without bias.
Joe Dilorio, President
The Caryn Company
Jerry Baril, P.E.
Public Works Manager
Fuscoe, Williams, Lindgren & Short, Inc.
P -1
FOREWORD
A primary purpose of this Summary Report for the Upper Etiwanda/San Sevaine Watersheds is to
consolidate information from the various documents that have been produced over a period of several
years. These documents involve studies that have investigated numerous alternatives and resulted in
recommendations for flood control, debris control, detention for runoff mitigation and /or peak flow
reduction, and water percolation /conservation facilities.
The studies and recommendations have also involved many consultants, public and private organizations,
individuals, and steering or technical committees that have provided guidance and leadership in the
formulation of criteria and policy. FWLS wishes to acknowledge their past contributions. The following
organizations and individuals are acknowledged for their recent participation and interest:
San Bernardino County Flood Control District Consultants
Ken Miller, P.E., Director Bill Mann & Associates
John Steger, P.E., Assistant Director Bill Mann, P.E.
Kenneth D. Guidry, P.E., Chief, Water Resource Division Simons, Li & Associates
Robert Corchero, P.E., Chief, Planning Division Ruh -Ming Li, Ph.D., P.E.
Jerry Ivy, P.E., Chief, Field Operations Division Paul Clopper, P.E.
Lewis S. Neeb, P.E., Etiwanda /San Sevaine Project Manager Geoproducts Co.
Chidi Onumonu, P.E. Jim Fish, Ph.D
Mohammad Ali, P.E. Dangermond & Associates
David Griffith, P.E. Pete Dangermond
Bob Lawrence, P.E. Bobbi Lyon
Williamson & Schmid
Etiwanda North Consortium Dick Schmid, P.E.
Mark Seits, P.E.
Joe DiIorio, The Caryn Company Land/Plan/Design
Chris Pauls, The Peninsula Group Jess Harris
Mike Kerney, Landmark Land Company Anita Trevino
John Cheng, Etiwanda Heights Moore & Taber
Jeff Weber, Standard Pacific Douglas Bell, P.E.
Craig Page, Ahmanson Development Engineering- Science, Inc.
Tom Tracy, Tracy & Haigh Development Company David Hall, P.E.
Kevin Pohlson, Akins Development Golf Course Architect
Jeff Pierson, Unitex Management Corporation David Rainville
Rivertech, Inc.
City of Rancho Cucamonga Hasan Nouri, P.E.
Fuscoe, Williams, Lindgren
Russell Maguire, P.E., City Engineer & Short, Inc.
Shintu Bose, P.E., Asst. City Engineer Pat Fuscoe, P.E.
Walt Stickney, P.E. Don Lindgren, P.E.
Dan James, P.E. Ray Allard, P.E.
Miki Bratt Jerry Baril, P.E.
Lan Weber, Ph.D., P.E.
F -1
EXECUTIVE SUMMARY
UPPER ETIWANDA/SAN SEVAINE WATERSHEDS
ALTERNATIVES FOR FLOOD CONTROL AND WATER CONSERVATION
AUTHORIZATION
This Summary Report was prepared by Fuscoe, Williams, Lindgren & Short, Inc. under contract with
the Caryn Company, on behalf of the Etiwanda North Land Owners Consortium.
PURPOSE
The Etiwanda North Specific Plan and draft EIR, currently in the developmental stage, are the impetus
for this Summary Report. The purpose being to consolidate the numerous flood control, debris
catchment, runoff mitigation, and water conservation alternatives that have been proposed or analyzed
over the past 7 years to facilitate the development of Etiwanda north, and the Etiwanda /San Sevaine
Watersheds in general.
The focus of this report will be to categorize overall project solutions in general terms, as discussed
below and in Section 4, with the purpose of establishing concept choices for meeting the various agency,
environmental, and /or land development objectives. Within these project solutions, specific alternatives
are presented in terms of channel, debris, detention, and water conservation facilities. However, this
is not intended to preclude the choice of other alternatives or options.
LOCATION
The limits of the Upper Etiwanda /San Sevaine Watersheds, and location of the various flood control and
water conservation facilities are shown on the project area map following this Executive Summary. The
downstream limit of facilities considered in this report is the San Bernardino Flood Control District's
recently constructed Etiwanda /San Sevaine double or side by side flood control channels south of I -15
at Victoria Street.
E -1
The upstream limit of facilities in Etiwanda Creek is in the vicinity of the canyon mouth above the
LADWP utility corridor, where several alternative sites and types of debris catchment facilities have
been investigated. The upstream limit of facilities in San Sevaine Creek is Basin No. 1 below Wilson
Avenue (24th Street).
BACKGROUND
The County of San Bernardino, the County Flood Control District, and several engineering consultants
have been involved in the planning and construction of flood control facilities in the Etiwanda and San
Sevaine Watersheds for several years. This Summary Report, however, deals primarily with the more
recent planning efforts in conjunction with the Etiwanda North Specific Plan, the North Etiwanda Land
Owners Consortium in general, and the Consortium's Flood Control Sub - Committee.
The County of San Bernardino Flood Control District is currently on a parallel path with the Etiwanda
North Land Owners Consortium in developing a flood control channel and debris facility in the Upper
Etiwanda Watershed on Etiwanda Creek. The District's project is a rectangular concrete channel with
a debris dam at the mouth of Etiwanda Canyon. Financing would be accomplished with a Bureau of
Reclamation loan. Being a Bureau sponsored project, the primary purpose is to beneficially use runoff
water. Runoff will be conveyed to percolation basins along the creek, and stored in the Chino
Groundwater Basin until needed by users for municipal, industrial, and agricultural purposes. A Federal
Environmental Finding of No Significant Impact (FONSI) was recently issued. State environmental
clearance (CEQA) remains to be obtained. EPA clearance may be needed, and of course, FEMA
approval is needed eventually.
The Etiwanda North Land Owners are pursuing a project that would provide flood protection, including
a debris facility, runoff mitigation, and replacement /preservation of existing water percolation facilities.
The purpose of their project is to allow development to occur in the area in accordance with the
Etiwanda North Specific Plan. However, because of significant project issues, it has been necessary to
examine numerous project alternatives and solutions.
4k
E -2
PROJECT ISSUES
The development of Etiwanda North will eventually require the resolution of several major flood control
and water related issues, which are outlined below, in order to focus on an overall project solution. The
issues revolve around five basic concerns which are discussed in detail in Section 2. Fundamentally,
the question is what type of flood control system can be constructed for Etiwanda Creek that:
(1) Meets the land development objectives of the North Etiwanda Land Owners Consortium
and is approvable by the appropriate local agencies
(2) Provides 100 -year FEMA approved flood protection for proposed development in the
Etiwanda North Specific Plan area
(3) Can be reasonably permitted by the U.S. Army Corps of Engineers and California
Department of Fish & Game
(4) Provides water conservation with or without a Bureau of Reclamation loan for the
channel construction
(5) Will be accepted for ownership and maintenance by the San Bernardino County Flood
Control District
The five relative concerns or issues are:
(1) FEMA Clearance
- The 1983 SBCFCD Master Plan Standard high velocity concrete channel versus a
very wide but limited velocity concrete or armorflex channel to mitigate cavitation
problems as perceived by FEMA
(2) Peak Flow Mitigation
- Diversion of Etiwanda Creek to San Sevaine Basin No. 5 for peak flow reduction
in lieu of providing flow detention in the Etiwanda Spreading Grounds Area as a
more efficient use of existing facilities
(3) Water Conservation
- Providing water percolation beds within the San Sevaine Basins in lieu of the
A Etiwanda Spreading Grounds to allow other land uses on the site
E -3
(4) Use of Flood Control District Properties
- The District's equitable share of flood control improvement costs, relative to the sale
of surplus District right -of -way created by the improvements
- Equity considerations for excess District revenues created by the development of
Etiwanda north, relative to 0 & M costs for the flood control improvements
(5) Environmental
- Preservation /perpetuation of existing alluvial fan scrub habitat
- Protection of existing critical habitat
- Feasibility of more environmentally sensitive flood control solutions versus
conventional concrete channels
- Areas to be designated as mitigation for development on existing alluvial fan habitat
PROJECT ALTERNATIVE FACILI'T'IES INVESTIGATED
In response to various constraints and issues as noted above, it has been necessary to investigate a great
number of project alternatives for flood control, debris catchment, detention basins, and water
conservation facilities. Project alternatives are discussed in detail in Section 3. The alternatives noted
below represent project facilities considered most feasible as a result of initial studies, and recent
additions as a result of either perceived closure or non - closure of project issues. The following outlines
the project alternatives in terms of the four major facility categories and general options that were
considered:
0 Channel Facilities
- Rectangular, trapezoidal, parabolic, and composite cross sections
- Cast -in -place concrete lining
- Armorflex concrete block lining
- Limited versus unlimited channel velocities
me
- FEMA versus County Design Standards
a
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O Debris Facilities
- Debris basin versus dam
- Multiple debris basins /dams
- Dual purpose debris /detention basin or dam
- State Division of Safety of Dams jurisdictional versus non jurisdictional debris
dam/basin
- Canyon mouth versus upstream canyon locations
- Canyon mouth versus downstream location with containment levees
O Detention Facilities
- Diversion of all or a portion of Etiwanda Creek flows into San Sevaine Detention
Basins
- Single or multiple detention basin(s) in the Etiwanda Creek Spreading Grounds
north and south of Wilson Avenue
- Joint use equestrian or golf course detention facility in Etiwanda Creek Spreading
Grounds
- State Division of Safety of Dams jurisdictional versus non jurisdictional detention
basin
- Flow- through versus flow -by detention basins
- Detention basins located on versus off the Etiwanda Creek Mainstem for mitigation
of Master Plan Storm Drain flows
O Water Conservation Facilities
- San Sevaine Basins
- Etiwanda Spreading Grounds North and South of Wilson Avenue
- San Sevaine Wash
- Golf Course Ponds
- Golf course low flow meandering stream
- Etiwanda Creek armorflex channel lining versus concrete channel for percolation
of storm and low flows
- Mainstem concrete channel turnoffs for storm flow and low flow percolation
4
The advantages and disadvantages of the primary alternatives for the four major project facility
categories are presented in Section 3.
E -5
CATEGORICAL PROJECT SOLUTIONS
Any overall flood control solution that is selected for Etiwanda Creek will also involve the selection
of various alternatives under one of the following four proposed classifications of project improvements:
O Channel Facilities
O Debris Facilities
O Detention Facilities
O Water Conservation Facilities
The large number of project alternatives, solutions, and facility types led to the formulation of five
categorical project solutions which are outlined below and presented in detail in Section 4. A project
solution matrix and schematic plans are included and duplicates follow this Executive Summary. Other
project solutions could of course be formulated with a combination of the various alternatives within the
five categorical solutions. It should be noted that construction costs stated throughout this report are
° order of magnitude and do not include costs for design, right -of -way, inspection, contract administration,
mitigation, etc.
(1) SBCFCD 1983 Master Plan Solution
This solution is a conventional concrete flood control channel for Etiwanda Creek similar
to Day Creek. Design velocities exceed 70 feet per second (fps). Velocities in this high
range are known to cause cavitation, and are subject to close scrutiny by FEMA which has
a limit of 40 fps.
The following outlines the key elements of the SBCFCD 1983 Master Plan solution:
• High velocity rectangular concrete channel
• State jurisdictional debris dam at canyon mouth
• No peak runoff mitigation for the Etiwanda Watershed
de
• Peak runoff mitigation for the San Sevaine watershed in San Sevaine Basin No. 5
• Water conservation in San Sevaine Wash and Basins, and Victoria and Rich Basins
• Right -of -way requirement is 34 acres
• Construction cost is estimated to be $20.0 million
E-6
4 (2) Modified SBCFCD 1983 Master Plan Solution
4
The modified Master Plan Solution would substitute a wide, limited velocity conventional
concrete channel for Etiwanda Creek to eliminate the cavitation problem. The average
width of the modified channel would be approximately 60 feet, or about four times larger
than the approved Master Plan channel.
This solution would also include variations from the Master Plan by substituting a non -
jurisdictional debris "basin" for a state jurisdictional debris "dam" at the mouth of Etiwanda
Canyon; adding detention basins in the Etiwanda Spreading Grounds area for runoff
mitigation in the Etiwanda Watershed; and adding options for additional water conservation
capacity in San Sevaine Basins 2, 3 and 4, and the proposed detention basins in the
Etiwanda Spreading Grounds.
The following summarizes the key elements of the modified SBCFCD 1983 Master Plan
solution:
• Limited velocity rectangular concrete channel
• Non jurisdictional debris basin at canyon mouth
• Peak runoff mitigation for Etiwanda North development
• Peak runoff mitigation for the San Sevaine Watershed in Basin No. 5
• Water conservation in accordance with the 1983 Master Plan plus options for additional
capacity
• Right -of -way requirement is 51 acres
• Construction cost is estimated to be $25.0 million
(3) Environmental Levee Solution
The levee alternative has been presented as an environmental solution relative to expected
environmental mitigation requirements for development of Etiwanda North. It would
preserve approximately 215 acres of alluvial fan between Wilson Avenue and the Upper
SCE Utility Corridor. The levee solution is essentially a mitigation option in the event that
Day Creek and San Sevaine Wash are unavailable for mitigation.
E -7
This solution has the least long -term environmental impact. It provides for a parabolic
armorflex flood control channel for Etiwanda Creek downstream of Wilson Avenue.
From Wilson Avenue upstream, vegetated armorflex lined levees would be utilized to
capture and guide Etiwanda Creek runoff and debris flows down to Wilson Avenue.
The levee solution includes a dual function state jurisdictional debris dam /detention basin
on the upstream side of Wilson Avenue, and water conservation in San Sevaine Basin No.
5 with options for additional capacity in Basins 2, 3 and 4.
The following summarizes the key elements of the environmental levee solution:
• Vegetated armorflex lined levees upstream of Wilson Avenue
• Vegetated armorflex lined parabolic channel downstream of Wilson Avenue
• Dual function state jurisdictional debris dam and peak runoff mitigation facility at
Wilson Avenue for the Etiwanda Watershed
• Peak runoff mitigation for the San Sevaine Watershed in Basin No. 5
• Water conservation in San Sevaine Basin No. 5 plus options for additional capacity
• Right -of -way requirement is 230 acres
• Construction cost is estimated to be $20.0 million
(4) Composite Concrete /Armorflex Channel Solution
The composite Etiwanda Creek Channel solution provides a limited velocity concrete flood
control channel upstream of Wilson Avenue, and a vegetated parabolic armorflex channel
from Wilson Avenue downstream to the Districts existing concrete trapezoidal channel.
This solution is intended to compromise the use of armorflex in the milder downstream
slopes, and concrete in the steeper upper slopes.
This solution includes a non jurisdictional debris basin at the canyon mouth; detention for
runoff mitigation in the Etiwanda Spreading Grounds area for the Etiwanda Watershed; and
water conservation in San Sevaine Basin No. 5 with options for additional capacity in
Basins 2, 3 and 4, and the proposed detention basins in the Etiwanda Spreading Grounds.
E -8
4,
The key elements of the composite solution are summarized below:
• Limited velocity rectangular concrete channel upstream of Wilson Avenue
• Vegetated armorflex channel downstream of Wilson Avenue
• Non jurisdictional debris basin at the canyon mouth
• Peak runoff mitigation for Etiwanda North
• Peak runoff mitigation for the San Sevaine Watershed in Basin No. 5
• Water conservation in San Sevaine Basin No. 5 with options for additional capacity
• Right-of-way requirement is 56 acres
• Construction cost is estimated to be $25.0 million
(5) All Armorflex Channel Solution
This solution for Etiwanda Creek provides an all armorflex vegetated parabolic shaped
channel from the Districts existing facilities near San Sevaine Basin No. 5 to the proposed
debris basin at the canyon mouth. The armorflex channel is an environmentally acceptable
solution for flood control facilities. This alternative was selected by the Etiwanda North
Landowners Consortium Flood Control Sub - Committee as the preferred solution.
The debris facility for this solution is a non jurisdictional debris basin. Detention for
runoff mitigation in the Upper and Lower San Sevaine Watershed and the Upper Etiwanda
Watershed, would be provided entirely in the San Sevaine Basins. Water conservation
facilities would be in San Sevaine Basin No. 5 with options for additional capacity in
Basins 2, 3 and 4.
The key elements of the all armorflex solution are:
• Vegetated armorflex channel for the entire project
• Non jurisdictional debris basin at the canyon mouth
• Peak runoff mitigation in the San Sevaine Basins for the Etiwanda and San Sevaine
Watersheds
• Water conservation in San Sevaine Basin No. 5 with option for additional capacity
• Right -of -way requirement is 66 acres
• Construction cost is estimated to be $24.0 million
E -9
CONCLUSION
We believe any one of the five categorical solutions, or any combination of solutions, would work,
given the proper balancing of flood control, water conservation, environmental mitigation and financial
feasibility. It is the responsibility of those organizations involved in the completion of the Upper
Etiwanda /San Sevaine system to determine the proper balance between the factors.
We urge the use of this document as a guide to reaching consensus.
E -10
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41
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MI (4) COMPOSITE CONCRETE &
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CONSTRUCTION COST: $25,000,000 •
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21
BASIN
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OE'I BEGIN PROJECT
Ch'RE.xlnrera •land Sunnvrs
AM
SECTION 1
INTRODUCTION
1.1 General
The completion of the Upper Etiwanda /San Sevaine flood control system will require the construction
of various flood control and runoff mitigation facilities, and the preservation or relocation of water
conservation /percolation facilities. The location of these facilities, in either the Upper Etiwanda or
Upper San Sevaine Watersheds, along with the various construction and material options, have been the
focus of numerous studies, reports, and alternatives analysis. The purpose of this report is to present
and document all of the various alternatives studied in a brief summary type format, and to categorize
several overall project solutions, as outlined in Section 4.
It should be noted that mitigation of increased runoff due to development is required due to the lack of
inadequate downstream flood control facilities. This interim inadequate condition is expected to persist
for a period of five years or more within the County of San Bernardino boundary. Detention mitigation
facilities required at this time, with the exception of Jurupa and San Sevaine Basins, will not be required
according to the SBCFCD's ultimate Flood Control Master Plan.
The "Upper Etiwanda Creek and San Sevaine Creek Drainage Plans ", adopted by the City of Fontana
and San Bernardino County in September 1989, setsforth a five year project schedule for construction
of channels, debris basins, detention basins, and levees at a cost of $67,128,356. If this schedule goal
is met, all flood control deficiencies would be met down to the Riverside County line. Including, a
letter agreement between the two County Flood Control Districts limiting the 100 -year ultimate discharge
at the County line to 12,100 cfs.
However, existing flood control deficiencies in Riverside County may still be present. The presence
of these deficiencies is a concern primarily related to prolonged, smaller frequency storm flows causing
erosion of unimproved channels. Consequently, there is a concern that upstream detention facilities,
and /or diversion to achieve detention, will result in prolonged flows and aggravate the erosion problem.
This situation has been the subject of several past and ongoing meetings between the two District's and
consultants working in the area.
1 -1
1.2 Upper Etiwanda Watershed
Etiwanda North is primarily within the Upper Etiwanda Watershed. Flood control protection and
mitigation of runoff for the development of this area of Etiwanda North can be accomplished entirely
within the Etiwanda watershed. Water conservation /percolation requirements can also be achieved
within the Etiwanda Watershed, depending on the specific land development option that is ultimately
selected. However, preliminary studies by Bill Mann & Associates indicates that the current Etiwanda
Spreading Grounds capacity can be transferred to San Sevaine Basin 5. Additional capacity would be
available in Basins 2, 3 and 4 to accommodate an MWD proposal for spreading imported water.
The overall categorical project solutions discussed in Section 4 are for facilities located in the Etiwanda
Watershed, with the exception of water conservation /percolation facilities and runoff mitigation. A
number of the project alternatives for Etiwanda Creek involve solutions with potential environmental
impacts. Accordingly, it should be noted that the Environmental Protection Agency (EPA) now has
substantial and retroactive powers on flood control projects. Just recently, a permitted trapezoidal
concrete channel (California Fish & Game, U.S. Army Corps of Engineers, and Riverside County Flood
Control District) on Santa Gertrudis Creek was rejected by EPA. An armorflex lined concrete channel
was required by EPA to satisfy environmental concerns. And, this was a newly graded section located
between a newly constructed subdivision and arterial highway, with a fixed flood control right -of -way.
Consequently, the most realistic solution may very well be that which can be successfully permitted.
1.3 Upper San Sevaine Watershed
Flood protection and runoff mitigation for the portion of Etiwanda North within the Upper San Sevaine
Watershed is being accomplished within the San Sevaine watershed. Alternatives for diversion of
Etiwanda Creek flows into San Sevaine Basin No. 5 for runoff mitigation have been investigated. The
most practical solution from a timing and approval standpoint is to provide mitigation within the Upper
Etiwanda Watershed with no diversion. The most practical solution might also include the use of San
Sevaine Basin No. 5 for water conservation /percolation, with options for additional percolation in Basins
2 and 3 and the proposed Etiwanda Detention Basin(s).
1 -2
The practicality lies in the fact that the San Sevaine Basins are a permanent solution in terms of the
Flood Control Districts ultimate master plan, whereas, the alternative location for water percolation in
the Etiwanda Spreading Grounds, in conjunction with detention basins required on an interim basis, is
not necessarily a permanent solution.
The following documents are referenced for the San Sevaine and Etiwanda Watersheds:
O SBCFCD Flood Control Master Plan, Bill Mann & Associates, 1983
O Loan Application Report, Proposed San Sevaine Creek Water Project, County of San
Bernardino, Engineering- Science, Bill Mann & Associates, April 1986 (Draft)
O Hydrologic Analysis and Modeling of the San Sevaine Creek Watershed, Bill Mann &
Associates, Hall and Foreman, Inc., January 1987 (Revised)
O San Sevaine Basin No. 5, Interim Development Drainage Mitigation Investigation, August
19, 1980
O Hydrology Study for San Sevaine Spreading Grounds, in the County of San Bernardino,
October, 1988
O San Sevaine /Etiwanda Creek Hydrology and Basin Routing, Fuscoe, Williams, Lindgren
& Short, Inc., January 1989, September 1989
O Analysis of Alternative Detention Basin Sites for Mitigation of Etiwanda North Storm
Water Runoff, The Caryn Company, Fuscoe, Williams, Lindgren & Short, Inc., November
2, 1989
O Hydraulic Study for Upper San Sevaine Creek, Fuscoe, Williams, Lindgren & Short,
Inc., January 1989 (Revised)
O City of Rancho Cucamonga, Master Plan of Drainage, BSI Consultants, Inc., February
1989
O Master Plan for Ultimate Use of North Etiwanda Properties, The Caryn Company,
Etiwanda North Land Owners Consortium, April 17, 1989
O Revised Rich Basin Plan and Debris Management Plan for Hawker - Crawford Channel,
Rivertech, Inc., September 28, 1989
O Upper Etiwanda Creek and San Sevaine Creek Area Drainage Plan, City of Fontana and
San Bernardino County Department of Transportation/Flood Control, Environmental Public
Works Agency, September 1989
O North Etiwanda Specific Plan, Issue Paper on Water Conservation and Spreading of
Imported Water, Bill Mann & Associates, 1989.
1 -3
WS
O Etiwanda North Specific Plan, Land /Plan /Design
O Project Report for San Sevaine Channel, Williamson and Schmid, April 1990
O Etiwanda North Specific Plan EIR, Michael Brandman Associates
O Etiwanda North Resource Management Plan, Vail, Speck Taylor, Inc.
±bl
1-4
SECTION 2
PROJECT ISSUES
2.1 FEMA Clearance
All proposed solutions for the channelization or containment of Etiwanda Creek 100 -year flood and
debris flows must be in accordance with FEMA regulations. The existing flood hazard has been
determined by FWLS and FEMA approval has essentially been obtained as of this date. The proposed
solution selected will have to remove the flood hazard. The process will commence with a submittal to
FEMA requesting a CLOMR (Conditional Letter of Map Revision) to remove the flood hazard
designation conditioned on a proposed solution. The next step is to submit as-built plans to FEMA with
a request for a LOMR (Letter of Map Revision).
With the issuance of a LOMR, the process is essentially complete except for FEMA's actual revision
of the FIRM (Flood Insurance Rate Map) or other official flood hazard document. Flood insurance may
be required by a conventional mortgage lender until the LOMR is issued. Premiums paid within the last
year prior to issuance of the LOMR may be reimbursed. Federally guaranteed mortgage loans will
require flood insurance until the LOMR is issued.
The issue that arises stems from the SBCFCD's request for a LOMR from FEMA for the recently
constructed Day Creek Channel. This facility is a conventional rectangular concrete channel with
maximum velocities in excess of 70 fps. Channels with velocities in excess of about 40 fps are subject
to potential damage from cavitation. FEMA has therefore inquired as to what was provided for
mitigation of the high channel velocities.
In the case of a high velocity concrete channel, the numerous construction joints in the invert and walls
are the prime initiators of directional flow changes to produce cavitation. In Etiwanda Creek, medium
size sand in the flows will cause pitting to occur and initialize cavitation. High velocity confluences,
transitions, piers, multiple box culvert walls, differential settlement /displacement at joints, invert patches,
etc. produce directional changes in flows and contribute further to cavitation problems.
In response to this issue, FWLS recommends limiting velocities to 40 fps maximum in all concrete
wit
channel alternatives where the flood hydrograph indicates the potential for cavitation. The modified
2 -1
Master Plan, environmental levee, composite concrete /armorflex, and all armorflex solutions presented
in Section 4 under "Categorical project Solutions ", would be designed in accordance with FEMA
requirements.
2.2 Etiwanda Creek Runoff Mitigation
Development in the Etiwanda Watershed will result in an increase in peak flow runoff and volume.
Because of inadequate downstream facilities, it will be necessary to mitigate the increased peak flow
rates with detention basins.
Mitigation for proposed developments in the San Sevaine Watershed is being provided by proposed
modifications by FWLS and others to the San Sevaine Basins. Additionally, the San Sevaine basins
provide peak flow reduction for the mainstem ultimate downstream flood control system. Mitigation is
an interim requirement until the ultimate mainstem system is constructed. The mainstem peak flow
reduction also contributes in meeting an agreement between the SBCFCD and the Riverside County
Flood Control District (RCFCD). The agreement states that the 100 -year combined flows of Etiwanda
and San Sevaine Creek shall not exceed 12,100 cfs at the Riverside County line.
Two basic alternatives for mitigation of runoff in the Upper Etiwanda Watershed have been investigated.
One is to provide detention facilities within the Etiwanda Spreading Grounds above and below Wilson
Avenue. There are no major issues with this proposal. The second alternative is to divert a portion of
Etiwanda Creek flows into San Sevaine Basin No. 5. This proposal raises the following issues.
RCFCD is concerned about prolonged flows, due to detention, aggravating unimproved earth channels.
Certain downstream facilities in Riverside County have as little as 2,500 cfs capacity. They are also
.4�
concerned about the timing of their improvements lagging behind upstream
improvements which will deliver storm flows more expediently. Although, the agreement deals strictly
with the ultimate maximum flow rate at the County line, the concerns outlined above have turned the
diversion question into an issue which cannot be ignored.
The proposed diversion of Etiwanda flows has also created an issue with the SBCFCD regarding the
"taking" of detention capacity away from the San Sevaine Watershed. The diversion alternative by
2 -2
.p
FWLS is based on development allowed by existing planning documents. The District is of the opinion
that density changes within the City of Fontana are very possible and would prefer to reserve detention
capacity in the San Sevaine Basins. FWLS recently performed a sensitivity analysis on this alternative
with double the density currently allowed in the City of Fontana. No major impacts on the basin
capacity were found.
2.3 Water Conservation
Current water conservation practices in the Etiwanda Spreading Grounds, which are adjacent to Etiwanda
Creek above and below Wilson Avenue, involve three modes of operation:
(1) Water replenishment in the Chino Groundwater Basin aquifer for overdrafts by water
purveyors. The Chino Basin has been adjudicated by the courts which allocated the safe
yield to be pumped between municipal, industrial, and agricultural users. The Chino Basin
Water Master, appointed by the court, manages withdrawals. If any user pumps water in
excess of their allocation, replenishment water must be purchased from MWD and
percolated into the underground basin. MWD has a turnout into the Etiwanda Spreading
Grounds, from their Rialto feeder line in Wilson Avenue, which is utilized for that
purpose.
(2) Spreading of MWD water for cyclic storage in "wet years ".
(3) Spreading of local drainage flows by the SBCFCD for water conservation.
A future practice has been proposed by both MWD and CBMWD involving the spreading of imported
water in both the Etiwanda Spreading Grounds and San Sevaine Basin No. 5 for underground storage.
This proposal is an alternative to surface storage as a means of reducing evaporation losses and other
impacts.
Preliminary studies by Bill Mann & Associates investigated the alternatives for water conservation if the
Etiwanda Spreading Grounds were developed for other uses. The study concluded that:
44
2 -3
(1) The current practice and volume of water conservation in the Etiwanda Spreading Grounds
can be transferred to San Sevaine Basin No. 5. That is, the replenishment, cyclic storage,
and spreading of local drainage flows.
(2) A future proposed practice by MWD and CBMWD for percolation and underground
storage of imported water can not be accommodated in San Sevaine Basin No. 5, in
addition to the capacity requirements proposed to be transferred from the Etiwanda
Spreading Grounds.
(3) Both current and possible future water conservation practices could be accommodated in
San Sevaine Basins 2, 3, 4 and 5. Basin No. 1 will receive debris laden flows and
therefore can not be used for percolation.
The issue in the matter of water conservation is one of jurisdictional agency approval for transferring
the percolation capacity of the Etiwanda Spreading Grounds to the San Sevaine Basins in the event that
the spreading grounds are developed for other uses. Initial contacts with the concerned agencies by Bill
Mann & Associates indicated no objections as long as the necessary recharge capacity is obtained.
2.4 Financial Plan, Use of Floodway Properties
To be acceptable and enforceable, the Financial Plan must balance:
A. An economic effective flood control solution with a solution that is environmentally
sensitive.
B. The desire to maintain floodway land as permanent open space with the property rights of
the floodway property owners.
0 Environmental and Political Concerns
Satisfying environmental and political concerns has a greater financial impact than the
engineering flood control solution itself.
To date, State and Federal agencies have indicated they want the remaining approvals for
Day, Etiwanda and San Sevaine Creeks treated as one application, with an environmental
plan covering all three Creeks, showing two of the three Creeks kept primarily as
2 -4
permanent open space, and an open space corridor left on the third. San Sevaine Wash
is the preferred open space because of the quality of its natural habitat. Day Creek,
possibly with a modification to its diversion, is the second alternative because 200 acres
of open space already exist there. If the Day Creek diversion levee should be modified,
but cannot be, then Etiwanda becomes the preferred alternative. If San Sevaine Wash is
allowed to be at least partially developed, then both Etiwanda and Day Creeks, and
probably additional land, will be required to be retained as permanent open space. One
or more of the agencies may not accept this last solution.
In contrast, the Flood Control District, as a result of processing it's Bureau of Reclamation
loan for the District's Etiwanda Creek project, has been allowed by a Federal agency to
plan open space mitigation only below 24th Street, in the Etiwanda and San Sevaine
Basins. However, the Bureau project still has to be processed by the Federal and Sate
agencies who are requiring the greater amount of open space.
Locally, the City of Rancho cucamonga's General Plan indicates a desire for some form
of open space in all three washes with a possible emphasis on day and San Sevaine. As
the controlling document, the County's General Plan shows the areas as Floodway, a form
of open space that can be changed only by the County's Board of Supervisors.
0 Technical Flood Control Solutions
The categorical flood control engineering solutions shown in Section 4 of this report
answer the technical concerns of the Federal, State and local agencies. All could keep San
Sevaine Wash as open space. Some would also keep Day Creek as open space; others
would keep Etiwanda as open space. All would cost between $20,000,000 and
$25,000,000.
0 Financial Impacts
Compared to the costs of the engineering solutions, the dollar impacts associated with the
A
resolution of the environmental and political concerns are probably around three times
greater, at $60,000,000 or more, depending upon what one assumes for land values. The
values used in this report are strictly estimates by The Caryn Company and it is assumed
that certified appraisers will establish actual values according to government regulations.
Equally important as the magnitude of the dollars is the question of who pays and who
2 -5
collects the dollars. At one extreme, the floodway property owners would not be allowed
to develop their properties and would be denied any compensation for keeping the
properties in open space. This probably is not legal. Another extreme would allow the
owners to develop all of their property and not provide any open space. This probably
is not environmentally acceptable. A third extreme would be for one or more entities to
come up with $60,000,000 to compensate the landowners and preserve all the land as open
space. This probably is not economically feasible.
O A Balanced Approach
A balanced approach might be to establish land values for all the affected parcels, allow
development on the less sensitive parcels and pay to acquire the development rights on the
more sensitive parcels. The cost of acquisition would be added to the costs of any other
environmental mitigation and the total costs spread equitably among all landowners,
including the Flood Control District, both within Etiwanda North and throughout at least
the remaining Etiwanda and San Sevaine watersheds.
O Balanced Approach Master Plan
The San Bernardino County Flood Control District is both the lead agency and the largest
landowner in Etiwanda North so the Master Plan tends to revolve around the District's
properties. The District, the County, City and Consortium have been developing the
Master Plan for the District's properties. A draft plan was submitted April 17, 1989 for
discussion. An update of that plan is presented here. The plan is designed to keep the San
Sevaine and Day Washes, at least above Wilson, as permanent open space. Low and very
low density residential development and the schools and parks required by that development
would be allowed outside the Day Creek Levee, inside the Levee if and when Wilson
extends across the Wash, and along Etiwanda Creek as part of a public golf course and
open space corridor design.
A similar plan could be developed leaving Etiwanda Creek as open space and allowing a
golf course development in Day Creek Wash. However, a similar plan could not be
developed for San Sevaine Wash because there isn't enough space there to fit a golf
course. The plan presented here is to be analyzed as a concept of a balanced approach,
not as a specific proposal.
2-6
O Concept
- An integrated financial plan for both improvement and operations
- Possibly three phases of implementation (see Map following this section)
1. Upper Etiwanda -San Sevaine area
2. The golf course area
3. The Day Creek area
- The first phase can be included in the current Etiwanda North Specific Plan, the later
two phases can be amendments to the Specific Plan
0 Phase 1 - The Upper Etiwanda -San Sevaine Area
- Specific revisions and additions to the Districts 1983 Flood Control Master Plan have
been proposed in response to intensified environmental scrutiny:
(1) Relocation of the proposed Etiwanda debris dam for preservation of more
natural creek habitat
(2) The use of an environmentally superior channel in lieu of a conventional
rectangular concrete channel
(3) Provisions for a possible wildlife corridor along the length of Etiwanda
Channel
(4) Establishment of a wetlands area at the south end of the channel
(5) Development of San Sevaine Basins as an extension of the wildlife
corridors
(6) The preservation of San Sevaine Wash between the basins and the national
forest
(7) The purchase of 210 acres of District easements in San Sevaine Wash and
Etiwanda Spreading Grounds to preclude development.
- Sixty acres of projected "surplus" District properties would be designated for low
density residential development
0 Phase 2 - The Possible Golf Course Area
- The improvement of Etiwanda Creek could make available some 424 acres of District
property for permanent open space and /or development. The Master Plan proposes:
(1) A possible 18 hole golf course on 226 acres
(2) Low density residential development on 72 acres
2 -7
- Golf course would fulfill a known recreational need and enhance the wildlife corridor
- Residential development would pay for the cost of developing the golf course
- The District would derive revenue from the golf course operation
O Phase 3 - The Day Creek Spreading Grounds Area
- West of Day Creek to Milliken and north of Banyan, there is an additional 787 acres
of District property not needed for flood control purposes, excluding the 200 acres
already set aside as open space mitigation for the construction of Day Creek. Also
in this area, generally between Day Creek and the Day Creek Levee is where the
proposed Rock Crusher and quarrying operation is scheduled to be located. The plan
proposes that the area above Banyan ultimately be designated as permanent open
space rehabilitated and renamed "Chaffey Regional Park" to reflect the Rancho
Cucamonga General Plan. Should it be ultimately decided to extend Wilson across
Day Creek Wash, then the 120 acres in the Wash south of Wilson, north of Banyan
would be used for very low density residential development. The area south and west
of the Day Creek Levee would be designated for a 40 acre High School site and 215
acres of low and very low residential development. The timing of this Phase would
be influenced by the settlement of the Rock Crusher litigation against the County.
O Financial Plan - Capital Sources and Expenditures
- Revenue from fees, taxes and the sale of parcels of land should offset the cost of
acquisition of other properties, the environmental enhancements to flood control
facilities, the provision of enhanced open space for community environmental
purposes and the construction of recreational areas such as parks and a golf course
and still leave the majority of the sales proceeds available for other uses. Accounting
of the phase -by -phase capital expenditures and land sales revenues is as follows,
assuming the flood control facilities themselves (dams, channels and basins) will be
provided by private developers at no cost to the District. Please note that all land
values, acreages and uses are only Caryn Company estimates, for comparative
purposes only.
2 -8
PHASE 1: (RAW LAND SALES)
Sale of 20 acres for development into 40 residential units $ 1,600,000
Sale of 40.86 acres for development into 163 residential units 5,720,000
Sale of 40 acres for school /park use 1,300,000
Purchase of 210 acres of land for permanent open space (5,300,000)
Land purchase reimbursement from fees and taxes 5.300.000
Surplus from Phase I $ 8,620,000
PHASE 2: (TENTATIVE MAP SALES)
Sale of 72 acres for development into 210 residential units along
a golf course $ 17,850,000
Construction of a golf course 4,750,000
Environmental mitigation to flood control improvements (1) 9.477.000
Surplus from Phase 2 3.623.000
Cumulative Surplus $ 12,243,000
PHASE 3: (TENTATIVE MAP SALES)
Sale of 215 acres in the Day Creek Spreading Grounds for development
into 430 residential units $ 27,950,000
Sale of 40 acres for High School site 2,000,000
Sale of approximately 400 acres as open space (2) 10,000,000
Contribution to the construction of Chaffey Regional Nature Park (3) 3,250.000
Surplus from Phase 3 36.700.000
Cumulative Surplus $ 48,943,000
Total: All income from Land Sales to District $ 61,720,000
Total: All Capital Expenditures by District 22.777.000
Total: Available for Other Uses for District $ 48,943,000
(1) Assumes District would be directly responsible for some environmental
mitigation, and /or required to pay a like amount as its proportionate share
of the watershed drainage fees.
(2) Of the 400 acres, approximately 120 acres between Banyan and Wilson
Avenues could be developed as very low density residential, probably at
a higher residential land value.
(3) This cost could include the cost of modifying the Day Creek Levee or
acquiring clear title to the Rock Crusher property.
•
2 -9
0 Financial Plan - Operating Income and Expenses
- None of the environmental improvements should cause ongoing expense to the
District. The very nature of the natural open space desired by the State Fish and
Game and U.S. Fish and Wildlife Service is such that it should thrive in this area
without artificial irrigation or intensive maintenance. The golf course is an asset that
can be leased to an operator on terms such that the District receives a share of the
ffi net operating income, with no liability for operating expenses. The only ongoing cost
to the District will be the normal annual maintenance of the actual flood control
facilities. FWLS estimates that this will cost an average of $250,000 per year once
all facilities are completed.
- The District will receive ongoing revenues from several sources. First, it will
receive a 4.60 percent of the base property tax revenues from those properties already
zoned for residential use. Second, the District will receive additional revenues from
the base property taxes generated by those units to be built on the District's surplus
properties. Finally, the District will receive income from the golf course lease.
- Revenue and Expense Recap for District:
ONGOING REVENUES AT BUILDOUT:
Base tax revenues from properties in ENSP (5080 du)(1) $ 1,000,000
Base tax revenues from homes on District's property (640 du)(2) 100,000
Revenues from golf course operations 200.000
Total Ongoing Revenues $ 1,300,000
ONGOING EXPENSES AT BUILDOUT:
Annual maintenance of flood control facilities $ 250,000
Contingency 250,000
Total Ongoing Expenses $ 500,000
NET FUNDS AVAILABLE FOR OTHER USES $1,000,000
_ (1) Includes the 203 District units in Phase 1.
(2) Includes District's Phase 2 and 3. Could be approximately 240 du higher
if District property between Banyan and Wilson is developed.
2 -10
O Consensus Building
1. Agree on the approximate amount, type and location of properties to be used for open
space mitigation.
2. Agree upon land uses for all floodway properties, ignoring open space mitigation
requirement.
3. Appraise all properties on a residual land value basis, accounting for the cost of area -
wide and site specific improvements plus any effect on value caused by current
zoning.
4. Establish value of properties to be used for mitigation, spread costs of acquiring
mitigation property over all property in watershed area.
5. Establish a CFD for a financial mechanism that allows for funds to be raised early
in development of Etiwanda North. Funds to be used for land acquisition,
environmental mitigation and technical flood control solution.
2.5 Environmental Mitigation Plan
A draft EIR has been prepared by Michael Brandman Associates for the Etiwanda North Specific Plan.
The reader is referred to this document for a detailed analysis. The two most critical environmental
issues affecting construction of flood control facilities are:
(1) Preservation /perpetuation of existing alluvial fan scrub habitat, and therefore the areas to
be designated as permanent open space
(2) Environmentally designed flood control solutions versus conventional concrete channels
The related political and economic issues with the greatest potential impact are the cost extent and
location of the areas to be preserved as open space. The preferred areas for mitigation are Day Creek
Wash (with a modified diversion levee) and San Sevaine Wash (as is). If these site(s) are not preserved,
Etiwanda Creek and adjacent land would likely be the alternative mitigation area. In turn, this would
have a major impact on the flood control facilities to be provided for Etiwanda Creek upstream of
Wilson Avenue, requiring that a levee system be used in lieu of any channel system. In contrast, the
Flood Control District has received a Finding of Non - Substantial Impact (FONSI) from the Federal
Government on the Districts Bureau of Reclamation application to build the Upper Etiwanda system.
The FONSI accepted substantially less mitigation as preserved open space than the State Department of
Fish and Game and the Federal Agencies of Fish and Wildlife, and the Corps of Engineers have
indicated would be required. If the District can have the FONSI accepted by these other agencies, then
hundreds of more acres of the District properties will be more clearly developable.
2 -11
As with the Financial Plan, the major question is "how much of the Districts properties should be
preserved as open space, at what cost, and who should pay ?"
2 -12
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SECTION 3
PROJECT ALTERNATIVES INVESTIGATED
3.1 Etiwanda Creek Channel Facilities
The Alternatives Analysis for Etiwanda Creek was initialized with the listing of all potential channel
cross sections and lining materials. The list was narrowed to feasible solutions and presented in the
Etiwanda Creek Drainage Corridor Design Concept Report in June of 1989. The following outlines the
initial alternative considerations and the outcome:
ALTERNATIVE REMARKS
1. Grassed lined channel Rejected as a hydraulically unstable erodible section due
to steep slopes
2. Combination low flow rectangular Rejected as a hydraulically unstable erodible section
concrete channel and grassed due to steep slopes
overflow section
3. Combination low flow rectangular Rejected for design velocity and cost considerations
concrete channel and armorflex
overflow section
4. Limited velocity rectangular channel Rejected as not feasible due to very short interval
with sloping apron grade reduction between drops, extreme width, cost and aesthetics
energy dissipators, in lieu of a
wide limited velocity channel
5. Trapezoidal concrete channel Rejected for design velocity hydraulic considerations
6. Armorflex lined channel with sloping Accepted for final evaluation. Rejected later as not
apron grade reducers required per factor of safety design calculations
7. Trapezoidal armorflex lined channel Accepted for final evaluation. Selected later for
restricted width locations only per factor of safety
design methodology
8. Rectangular concrete channel with Accepted for final evaluation
no velocity limitation
9. Wide rectangular concrete channel Accepted for final evaluation
with limited velocity
10. Parabolic armorflex lined channel Accepted for final evaluation
3 -1
The alternatives discussed in this section include modification of the existing channel reach from Victoria
Street upstream to San Sevaine Basin No. 5, and a proposed levee system above Wilson Avenue. All
proposed new facilities are discussed relative to upstream or downstream of Wilson Avenue. This
division point addresses both hydraulic and environmental considerations.
3.1.1 Existing Concrete Channel
Etiwanda Creek and San Sevaine Creek channels are older existing improved concrete channels in the
reach from Victoria Street upstream to San Sevaine Basin No. 5. From Victoria Street downstream,
both channels were recently improved to Foothill Boulevard. In both reaches the channels are separate,
but share a common center wall or berm. At Foothill the channels will ultimately combine, but
currently the flows split at Foothill.
The old concrete channels are irregular shaped sections. The basic shape is trapezoidal with the outer
walls sloping at 1.5H:1V. The common center portion is either a vertical wall or a sloping wall at
1.5H:1 V with a 5' separation berm. The irregular shape facilitates channel narrowing at road crossings.
} This system was designed using pre -1986 hydrologic data. Under current criteria and data, Etiwanda
Creek has a limited capacity of about 2,800 cubic feet per second (cfs) with freeboard allowances. With
zero freeboard, the capacity is 6,300 cfs. San Sevaine Channel has a capacity of 5, 200 cfs with
freeboard allowances, and 12,000 cfs with zero freeboard.
Final design flows for both existing Etiwanda and San Sevaine Channels have not been determined.
That determination is pending the selection of an alternative for detention mitigation. San Sevaine
Channel will most likely be adequate. However, Etiwanda Channel will most likely be inadequate.
Accordingly, this reach has been included in all of the categorical project solutions outlined in Section
4. The expansion of existing Etiwanda channel will be accomplished by converting the sloping outside
wall to a vertical wall at the extreme edge. Widening beyond that point would interfere with an existing
sewer line.
3.1.2 Alternative Facilities
The reach of Etiwanda Creek downstream of Wilson Avenue has an average slope of 3.5% in
comparison to 6% upstream. Accordingly, the hydraulic constraints are considerably less. However,
3 -2
4
the most hydraulically efficient rectangular concrete section in the lower reach would still have potential
cavitating velocities greater than 40 feet per second (fps). A parabolic armorflex section would have
essentially the same approximate design velocity of 20 fps upstream and
downstream of Wilson Avenue. The steeper slope results in a wider cross section to maintain the
current maximum design limitation of 20 fps for armorflex, which also maximizes the energy dissipation
provided by the built -in high flow resistance of armorflex. Above Wilson Avenue, the most
hydraulically efficient rectangular concrete section would have potential cavitating velocities in the 70
fps range. A levee system alternative upstream of Wilson Avenue is presented as one example of an
environmental solution. The function of the levees is to capture flood and debris flows discharging at
the mouth of Etiwanda Canyon, and guide the flows to Wilson Avenue. A debris basin could be located
at the canyon mouth, just upstream or downstream of Wilson, or on both sides of Wilson. A basin
located downstream of Wilson Avenue would require a clear span bridge to pass debris under the
roadway.
The levee system could be armored with rock or armorflex and bid as alternates. The lower portion
just upstream of Wilson Avenue would be combined with the dual debris /detention basin if located at
this site. For discussion purposes, the levee system comparisons below are for either armoring alternate,
and relative to a concrete or armorflex channel downstream of Wilson Avenue.
The following outlines the advantages and disadvantages identified by FWLS for the Etiwanda Creek
Channel alternatives:
4
9
9
3 -3
RECTANGULAR CONCRETE CHANNEL - LIMITED VELOCITY
UPSTREAM OR DOWNSTREAM OF WILSON AVENUE
ADVANTAGES
• Meets FEMA requirements • Hydraulic model studies not required
• Generally conforms with SBCFCD 1983 • Conventional hydraulic design
Master Plan
• SBCFCD will accept for operations and
• SBCFCD FONSI obtained for 1983 Master maintenance
Plan Facility is applicable
• Lower maintenance costs than a high velocity
channel
DISADVANTAGES
• Higher initial cost than high • Susceptible to graffiti
velocity channel
• Requires a 20 foot wide access road
• Not viewed as an environmental and chain link fence on each side of
solution, so it is more difficult channel
to obtain environmental permits
• Very difficult to integrate with a
• Aesthetically unpleasing golf course
• Maximum right -of -way take of channel • Can not be used to satisfy 300'
alternatives minimum width wildlife corridor
• Susceptible to earthquake damage
3 -4
7
RECTANGULAR CONCRETE CHANNEL - HIGH VELOCITY
` UPSTREAM OR DOWNSTREAM OF WILSON AVENUE
ADVANTAGES
• Lower initial construction cost • Conventional hydraulic design
• Conforms with SBCFCD 1983 Master Plan • SBCFCD will accept for operations and
maintenance
• Minimizes right -of -way requirements • SBCFCD has obtained a FONSI for this
type of facility
DISADVANTAGES
• FEMA clearance may be difficult to obtain • Susceptible to graffiti
due to high cavitational velocities
• Higher maintenance or replacement costs
• May require hydraulic model studies to repair potential cavitational damage
• Aesthetically unpleasing • Requires a 20 foot wide access road and
chain link fence on each side of channel
• Not viewed as an environmental
solution, so it is more difficult • Difficult to integrate with a golf course
to obtain environmental permits
• Can not be used to satisfy 300'
• Susceptible to earthquake damage minimum width wildlife corridor
3 -5
PARABOLIC ARMORFLEX LINED CHANNEL
UPSTREAM OR DOWNSTREAM OF WILSON AVENUE
ADVANTAGES
• Accepted as an environmental • Chain link fencing could be safely
flood control solution eliminated due to low edge velocities
• Water percolation through armorflex • Ease in obtaining environmental permits
lining provides water conservation
• Facility could be maintained by the
• Aesthetically pleasing with grassed surface District or jointly as an integral part
of a golf course
• Easily integrated with golf course
• Equal in initial cost to a wide limited
• Graffiti proof velocity concrete channel
• Lower maintenance costs than high • Armorflex channels can be integrated with
velocity concrete channel a wildlife corridor to satisfy 300' minimum
width requirement
• Virtually unsusceptible to earthquake
damage • Minimizes development mitigation
requirements
• Rodent proof relative to rip -rap • Allows planting of small trees in channel
lined channels or levees
DISADVANTAGES
• Higher initial cost than high velocity • Operation and maintenance by the District
concrete channel is an issue
• Right -of -way width greater than high • No operational track record for armorflex
velocity concrete channel without in this area
wildlife corridor
3 -6
LEVEE SYSTEM UPSTREAM OF WILSON AVENUE
ADVANTAGES
• Accepted as an environmental solution • Allows flexibility for future uses of
the area for homes and /or golf courses if
• Lease initial construction cost of not permanently set aside for mitigation
all alternatives
• Allows flexibility for agreements for future
• Preserves existing alluvial fan mitigation trade offs in other areas
habitat
• A vegetated armorflex levee would look
• Preserves alluvial fan process if natural and allow the flexibility for
combined with a debris basin just re -using the lining for a future channel
upstream of Wilson Avenue system
DISADVANTAGES
• Levees could be aesthetically • Cost of a rock levee system would in
unpleasing, especially in essence be a throw away if area use changes
conjunction with a debris basin in the future
at Wilson Avenue
• Potentially uses SBCFCD property for
• Rock levees attract rodents mitigation
• Maximum right -of -way take of all • Eliminates development in this area at this
alternatives time, or may in perpetuity, if used for
development mitigation purposes
a
3 -7
3.2 Etiwanda Creek Debris Facilities
The alternatives analysis for a debris facility were initiated by geotechnical and critical habitat
constraints, relative to the SBCFCD 1983 Master Plan debris dam and site location. Other alternatives
investigated later were in response to land use planning, additional environmental issues, and access
considerations for the areas east and west of Etiwanda Creek adjacent to the basin site. The following
outlines the various alternatives investigated and the outcome:
ALTERNATIVE REMARKS
(1) Debris basins or dams in the canyons Rejected for costs, effectiveness, potential
above the mouth in national forest. environmental impacts, location in the Cleveland
National Forest, and access difficulties.
(2) Debris dam approximately 2,700' Rejected for the following reasons:
north of the LADWP utility corridor. This dam, site No. 3 per the Etiwanda Design
Concept Report, would be more than 100' in
height, be located in an active seismic
area, require state approval, and have severe
access difficulties.
(3) Debris basin approximately 1,600' Rejected for land planning access reasons and
north of the LADWP utility corridor. impact on habitat along westerly side of
Etiwanda Canyon. This site was designated No. 2
in the Etiwanda Design Concept Report.
(4) Debris dam or basin at canyon mouth Accepted for final evaluation. This site was
just above LADWP utility corridor. designated No. 1 in the Etiwanda Design
Concept Report.
(5) Dual debris /detention facilities at Accepted for final evaluation.
canyon mouth site no. 1.
(6) Dual debris /detention facilities at Accepted for final evaluation.
Wilson Avenue.
(7) Dual debris /detention facilities at Accepted for final evaluation.
canyon mouth site No. 1 and Wilson
Avenue.
3 -8
As stated earlier, initial constraints affecting the type and location of a debris catchment facility were
geotechnical and critical habitat related. The geotechnical constraint was seismic which has since been
magnified by the recent Upland earthquake. Preservation of alluvial fan habitat has also intensified as
an environmental issue since initial evaluations. An updated geotechnical report was also completed in
March 1990. Ground water was identified in the report as a design constraint for a debris basin
constructed below existing ground level. However, recommendations were presented for mitigating this
problem. The geotechnical investigation also located an active strand of the Cucamonga fault near the
basin outlet tower. Relocation of the tower as shown on the preliminary design plans has been
recommended as mitigation.
It should also be noted that the volume of debris originally estimated to be generated from Etiwanda
Canyon was 400,000 cubic yards. The SBCFCD now estimates this volume, including 20%
contingency, to be nearly 700,000 cubic yards. This large volume made it necessary to carefully re-
orient the basin to avoid a major impact on the nearby critical habitat.
The following outlines the advantages and disadvantages for the alternatives selected for final evaluation:
3 -9
DEBRIS BASIN AT CANYON MOUTH
ADVANTAGES
• A basin below ground, in lieu of a dam • Basin concept places the debris
above ground, mitigates seismic constraints catchment essentially out of sight
• A basin is safe against catastrophic failures • Basin excavation can be utilized for
development grading and construction
• A high velocity spillway is not required. rock materials
The downstream channel serves as a basin
outlet and channel inlet • A basin, in lieu of a dam, does not
fall within the jurisdiction of the State
• Annual maintenance and safety administrative Division of Dam Safety
costs are less for a basin than a state
jurisdictional dam facility • Allows development or preservation of
downstream areas
• Basin depth may result in year around low • Basin concept decreases the design and
flows from the basin drain pipe to approval time
support downstream plant life in
a meandering golf course stream or • Location of basin at canyon mouth provides
natural state factor of safety for deposition of debris
downstream to Wilson Avenue if that area
is not developed
DISADVANTAGES
• A basin at the canyon mouth would eliminate • Requires a high outlet tower
the natural alluvial fan process, if the
area below is not developed • Requires a deep, long outlet drain
• Total area requirements are greater than • Inlet area is steep and requires armored
a dam erosion protection
• Basin concept will require longer construction • Environmental agencies appear to favor
time location of facility at Wilson Avenue
3 -10
DEBRIS DAM AT CANYON MOUTH
ADVANTAGES
• Dam is in conformance with SBCFCD 1983 • Total land area requirement is less than
Master Plan a basin
♦ Allows development or preservation • SBCFCD FONSI for Bureau project on
of downstream areas Etiwanda Creek is for a dam facility
• Dam outlet tower is shorter and simpler • Dam outlet drain is shorter and shallower
than a basin tower than a basin drain
DISADVANTAGES
• Seismic constraints are difficult and • Dam will fall within the jurisdiction
costly to mitigate because of active of the State Division of Dam Safety
faults located directly at dam site
• A dam poses a threat of sudden failure
• Dam concept will increase design and
approval time • Annual maintenance and safety
administrative costs are greater for a
• Dam is aesthetically less pleasing than dam than a basin
a basin
3 -11
DUAL DEBRIS/DETENTION DAM FACILITY AT WILSON AVENUE
ADVANTAGES
• Preserves alluvial fan process and • Dual use facility at one location requires
existing habitat above Wilson Avenue less land area
in conjunction with a levee system
• Viewed as an environmentally acceptable
solution
DISADVANTAGES
• Eliminates development option upstream • Dual facility is very large and high
of Wilson Avenue and can be aesthetically unpleasing
• Dual facility will be a State
jurisdictional dam • A dam at Wilson Avenue poses a
threat of sudden failure
• Dam concept will increase design
and approval time • Combining a debris and detention basin
is less desireable than separate
• Annual maintenance and safety facilities for operation and
administration costs are maintenance
greater for a dam than a basin
•
1
3 -12
DUAL DEBRIS/DETENTION FACILITIES WITH
A BASIN AT CANYON MOUTH AND DAM AT WILSON AVENUE
ADVANTAGES
• Provides options for both preserving • Two facility concept provides more
alluvial fan habitat, and future frequent flows to the alluvial fan than
land utilization above Wilson Avenue one at the canyon mouth which is
via expanding the upper basin and environmentally more acceptable
eliminating the lower dam
• Two smaller facilities would have less
• Two facility concept could reduce dam visual impact at Wilson Avenue than
at Wilson Avenue to State Division of one large basin or dam at that location
Dam Safety non jurisdictional status
DISADVANTAGES
• Two facilities would be more costly • Combining a debris and detention
than one basin is less desireable than separate
facilities for operation and maintenance
• Requires more land area than the
one facility concept • A dam at Wilson Avenue poses a threat
of sudden failure
• Annual maintenance is more costly
for two facilities than for one • Annual maintenance and safety
administration costs are greater
• Dam at Wilson Avenue will increase for a dam than a basin
design and approval time
• Would eliminate development upstream
of Wilson Avenue at this time
4
9
3 -13
3.3 Etiwanda North Runoff Mitigation Detention Facilities
The storm water detention facilities discussed in this section are for the proposed development areas in
the Etiwanda North Specific Plan, within the Upper Etiwanda Creek watershed. Mitigation of proposed
development in other portion of the Specific Plan area are being provided in the Day Creek and San
Sevaine Creek systems by prior agreements and plans.
Initially, mitigation for Upper Etiwanda was proposed to be provided by diversion of Etiwanda Creek
flows into San Sevaine Basin No. 5. Various percentages of diversion were investigated. The minimal
diversion studies accommodated only that amount required for Etiwanda North. The maximal amount
studied was 100% which was investigated relative to reduction in downstream channel facilities.
Subsequent to the initial mitigation proposal, issues were raised by the RCFCD and the SBCFCD
relative to diversion of Etiwanda Creek flows as discussed in Section 2.2. Consequently, alternatives
for mitigation in the Etiwanda Spreading Grounds were investigated. Later, dual debris /detention
facilities were investigated which was presented in Section 3.2.
3.3.1 Diversion to San Sevaine Basin No. 5
FWLS prepared a San Sevaine Basin Study in 1989 dealing with the Etiwanda Creek diversion concept
for mitigation. Two primary design schemes were investigated. One scheme considered multiple basins
(2 thru 5), and the other with one enlarged Basin 5 combined with Basin 4 (4/5). The one basin
alternative was recommended and the study was submitted to the SBCFCD for their review and
comment.
Based on the hydrology input and Basin 4/5 configuration presented in the September 1989 report, the
100 -year floods from San Sevaine and Hawker Crawford drainage areas and a partial diversion flow
(approximately 2500 cfs) from Etiwanda Creek were routed through the proposed basin. The capability
of the proposed Basin 4/5 to mitigate runoff increase within the San Sevaine, Hawker Crawford, and
Etiwanda Watersheds was confirmed. The county had limited comments on the September 1989 report.
FWLS performed a sensitivity analysis and found no major effect on the conclusion. A sensitivity
analysis on the potential changes on the Basin 4/5 capacity due to Rich Basin modifications was also
performed and no major impacts on the previous conclusions were found. A sensitivity analysis on the
3 -14
potential changes on the Basin 4/5 capacity due to double development density within the City of Fontana
was also performed and no major impacts on the previous conclusions were found. That is, the
proposed Basin 4/5 configuration could still mitigate North Etiwanda. In the event of runoff mitigation
of San Sevaine and Hawker Crawford Watersheds only, Basin 4/5 can be reduced by excluding the
Unitex area. Basin 5 alone (per Engineering Science design) can not handle the flow and meet the
downstream flood control requirements.
The following outlines the advantages and disadvantages of single and multiple basin schemes. The
comparisons are relative to the option of utilizing the 6 acre Intex parcel located adjacent to Basin 4.
The Intex parcel is required to provide the necessary mitigation capacity with the one basin option:
Af
3 -15
EXPAND AND COMBINE BASINS 4 & 5 - WITH INTEX PARCEL
(ONE BASIN CONCEPT)
ADVANTAGES
• Least construction cost alternative by • One basin concept eliminates the
increment of approximately $4,000,000, need for a state jurisdictional
excluding acquisition cost of 6 acre Intex dam created by the Wardman Bullock
parcel Road crossing between Basins 3 and
4 for the multiple basin concept
• Design and approval process time will be
shortened with a non jurisdictional
Wardman Bullock roadway crossing
DISADVANTAGES
• Diversion of Etiwanda Creek flows into • It may not be possible to
San Sevaine Basin 5 has been objected obtain a permit from the SBCFCD
to by both the SBCFCD and the RCFCD to do this work because of the
relative to reserve detention diversion issue
capacity and downstream channel
deficiencies
3 -16
COMBINE BASINS 2 & 3 AND EXPAND BASIN 4 & 5 - WITHOUT INTEX PARCEL
(MULTIPLE BASIN CONCEPT)
ADVANTAGES
• Allows development to occur on Intex • Provides greater detention capacity
6 acre parcel than one basin concept
• Requires emergency spillway and • Provides detention capacity in
overcrossing bridge on dam formed excess of requirements for Etiwanda
by Wardman Bullock Road crossing North that can be used for reserve
of basins, which would provide a capacity for the San Sevaine Watershed
factor of protection against debris
flows overtopping the roadway
DISADVANTAGES
• Multiple basin concept creates a • Design and approval time is longer
state jurisdictional dam formed by for a state jurisdictional dam
the Wardman Bullock Road crossing
of the basins
• Construction costs is greatest of • Complicates the proposed
all alternatives by an increment of realignment of Hawker Crawford
about $5,600,000, excluding acquisition Channel along I -15 during interim
cost of Intex 6 acre parcel, over the phase. Would require a 700' long
least cost alternative box culvert under Cherry Avenue
and Intex parcel to carry debris,
which SBCFCD would likely not
accept for maintenance
3 -17
3.3.2 Etiwanda Spreading Grounds
As stated earlier, the use of Etiwanda Spreading Grounds for runoff mitigation facilities was investigated
in response to the RCFCD and the SBCFCD concerns expressed over diversion of Etiwanda Creek flows
into San Sevaine Basin No. 5.
The original investigation for the use of the Etiwanda Spreading Grounds area for detention focused on
a series of non jurisdictional flow - through basins and one flow - through basin. Both facilities were
located in the Etiwanda Spreading Grounds on the north side of Wilson Avenue. The estimated
construction cost of both alternatives was approximately $5,000,000, excluding land acquisition costs.
However, the basins would be located on SBCFCD land and /or easement. Costs being equal, the one
basin state jurisdictional alternative facility was rejected for further consideration.
Subsequent to the above alternatives analysis, a study was initiated to investigate the use of detention
basins off of the mainstem. The concept is to provide detention at the outlets of the City of Rancho
Cucamonga Master Plan Storm Drains to be constructed in conjunction with the proposed land
developments. In accordance with the Master Plan, the Upper Etiwanda interceptor channel will capture
flows from the area above the channel which is to remain undeveloped. Virtually all developed areas
requiring detention mitigation will drain to Etiwanda Creek via the City Master Plan Drains.
Accordingly, all detention mitigation can be accomplished off of the mainstem.
Four Master Plan Drains are identified. Line XIV -3 enters Etiwanda Creek at the LADWP /SCE
corridor one mile north of Wilson Avenue. Line XIV -8g discharges into the creek at the lower SCE
corridor one half mile north of Wilson Avenue. Construction plans for this line are currently being
processed by developers to the west. Line XIV -9f is located in Wilson Avenue. Construction plans for
this line are also being processed by developers to the west. Both of the above storm drain lines being
processed include detention basins at their outlets in the Etiwanda Spreading Grounds. Either basin may
not be compatible with future development options.
The fourth Master Plan Line is XIV -23 located one half mile south of Wilson Avenue. Detention
mitigation required for this line would be accommodated in the alternative detention basins located
north and /or south of Wilson Avenue. This storm drain line would therefor discharge directly into the
proposed Etiwanda Channel.
3 -18
The alternatives analysis for detention facilities included more than twenty five basins either in series
or single. Joint use with a golf course was investigated and found feasible north of Wilson Ave. In all
cases, the basins are located north and /or south of Wilson Avenue within the Etiwanda Spreading
Grounds. The following outlines the advantages and disadvantages of the potential solutions:
igf 3 -19
ALL DETENTION NORTH OF WILSON AVENUE - ON MAINSTEM
NON - JURISDICTIONAL BASINS IN SERIES
ADVANTAGES
• A non jurisdictional facility requires • Basins in series are non jurisdictional
less time to design, obtain approval, whereas one basin only would result in
and construct a jurisdictional dam
• Not easily integrated with a golf course • Minimizes maximum height of
in comparison to a single basin visible slopes in comparison to
a single basin
DISADVANTAGES
• Operations and maintenance costs would be • Less aesthetic than one facility
greater than for a one basin facility because of numerous spillways required
for seven basins in series to obtain
• Basins in series less desireable than a required storage capacity
single basin from an 0 & M standpoint
• Could eliminate or delay use of
District lands for development relative
to the diversion concept
4
3 -20
ALL DETENTION NORTH OF WILSON AVENUE - OFF MAINSTEM
NON - JURISDICTIONAL BASINS - SINGLE OR IN SERIES
ADVANTAGES
• System can be designed as one non- • System can be designed as non-
jurisdictional basin compatible with jurisdictional basins in series
joint use as a golf course to minimize right -of -way take
• Requires less right -of -way than basins • Provides maximum flexibility for
both north and south of Wilson Avenue design and land use
• Detention facilities off mainstem facilitates
design for non jurisdictional basins
DISADVANTAGES
• Could eliminate or delay use of • Basins in series less desireable
District lands for development than a single basin from an 0 & M
relative to diversion concept standpoint
• Joint use concept for flood and • May not be considered a regional
recreation purposes would be new to facility for acceptance by the
the SBCFCD or City if accepted District for 0 & M
for 0 & M
11
3 -21
ALL DETENTION SOUTH OF WILSON AVENUE - OFF MAINSTEM
NON - JURISDICTIONAL BASINS - SINGLE OR IN SERIES
ADVANTAGES
• System can be designed as a non- • System can be designed for joint
jurisdictional single basin or a use with an equestrian center
series of basins
• Detention facilities off mainstem
• Provides flexibility for design facilitate design for non-
.
and land use jurisdictional basins
DISADVANTAGES
• Could eliminate or delay use of District • May not be considered a regional
properties for development relative facility for acceptance by the
to diversion concept District for 0 & M
• Joint use concept for flood and • Basins in series less desireable
recreation purposes would be new than a single basin from an 0 & M
to the SBCFCD or City if accepted standpoint
for O & M
3 -22
DETENTION NORTH AND SOUTH OF WILSON AVENUE - OFF MAINSTEM
NON - JURISDICTIONAL BASINS - SINGLE OR IN SERIES
ADVANTAGES
• System can be designed as a non- • Grading impact is lessened at
jurisdictional single basin or a each site by smaller basin
series of basins storage requirements
• Provides flexibility for design • Basin(s) south of Wilson can be
and land use designed for joint use with an
equestrian center
• Detention facilities off mainstem
facilitate design for non jurisdictional
basins
DISADVANTAGES
• Could eliminate or delay use of District • May not be considered a regional
properties for development relative to facility for acceptance by the
diversion concept District for 0 & M
• Joint use concept for flood and • Requires more land area than a
recreation purposes would be new to basin(s) at one site
the SBCFCD or City if accepted for
0 & M • Basins in series less desireable
than a single basin from an 0 & M
standpoint
3 -23
3.4 Water Conservation Facilities
The development of Etiwanda North has the potential of utilizing the existing Etiwanda Creek Spreading
Grounds located to the north and south of Wilson Avenue. The land use options on the north side could
be either golf course or residential. Land use options on the south side could be an equestrian center
or remain in its present use.
Replacement of the Etiwanda Spreading Grounds, in the event that this water conservation facility is
displaced by development, is a necessity for several important reasons. Those reasons include current
and future uses, legal considerations, and water conservation as environmental and social issues.
In response to those concerns, Bill Mann & Associates prepared an "Issue Paper on Water Conservation
and Spreading of Imported Water ". The paper analyzes and reviews alternatives to the use of Etiwanda
Creek Spreading Grounds totally or in part for spreading both local drainage flows for water
conservation, and imported water for groundwater replenishment. The following outlines and
paraphrases the report:
0 General
The spreading grounds north and south of Wilson Avenue are presently used for spreading of
local drainage flows by the Flood Control District. The spreading grounds on the north are also
being used for spreading of imported water and recharging the groundwater table by the Chino
•
Basin Municipal Water District (CBMWD). In addition, the proposed Bureau of Reclamation
Project (San Sevaine Water Project) includes the use of the spreading grounds for spreading of
local drainage flows for water conservation purposes.
This paper discusses the following items:
1. Bureau of Reclamation Project and alternative for replacing the loss of water spreading
capability in the Etiwanda Spreading Grounds.
4,
2. The proposed use of the Etiwanda Spreading Grounds for spreading imported water by
MWD.
3 -24
3. The existing and future uses of the Etiwanda Spreading Grounds by CBMWD for spreading
imported water.
4. Alternatives for spreading local drainage flow and storm flow by the Flood Control District
if the Etiwanda Spreading Grounds are partially or totally occupied by the golf course.
0 Bureau of Reclamation Project
1. Proposed Water Conservation in Etiwanda Spreading Grounds
The proposed Bureau of Reclamation (BOR) Project designates the use of the Etiwanda
Spreading Grounds and San Sevaine Basin No. 5 for water conservation.
The proposed storage indicated in the BOR Report (October, 1987) indicates 2,350 acre -feet of
storage in Basin No. 5 and 59 acre -feet of storage in the Etiwanda Spreading Grounds. The
proposed recharge capacity in Basin No. 5 was 234 acre - feet /day (117 cfs) and the proposed
recharge capacity in the Etiwanda Spreading Grounds is 42 acre - feet /day (21 cfs).
Based on the "annual conservable runoff" analysis provided for the BOR Report, a 117 acre-
feet /day recharge capacity in the Etiwanda Spreading Grounds is necessary. The recharge
capacity estimate is based on annual average rainfall, a 30 days /year "wet" basin, and a 2
feet /day sustained recharge rate.
Due to the necessary 117 acre - feet /day recharge capacity in the Etiwanda Creek drainage area
and the 42 acre - feet /day recharge capacity proposed in the Etiwanda Creek Spreading Grounds,
the BOR Project proposes to direct low flows from the Etiwanda Creek Channel to Basin No.
5 for storage and recharge by a 48 -inch pipe turnout. In accordance with the BOR Project,
approximately 75 acre - feet /day of the necessary recharge capacity will be transferred to Basin
No. 5 for recharge.
The original "dead storage" in the San Sevaine Basin No. 5 proposed under the BOR Project
was approximately 300 acre -feet. The dead storage was to be used for water conservation
purposes. Due to the need for interim drainage detention by the proposed developments in the
3 -25
San Sevaine Creek watershed, the dead storage for increased drainage detention was increased
to 645 acre -feet, or 736 acre -feet under the ultimate basin plan.
The total acre - feet /day recharge capacity necessary on the estimated "average annual conservable
runoff" for both the Etiwanda and San Sevaine Creek watershed areas is approximately 338 acre -
feet /day, based on a 2 feet /day recharge rate and a 30 -day "wet" basin per year. Although the
approximately 60 acres of basin bottom in proposed Basin No. 5 will not percolate the estimated
4.
average annual runoff from both the San Sevaine and Etiwanda Creek watersheds in the 30-
day period, the water can be stored in the basin until percolation occurs beyond the 30-day
period.
The BOR Project Report proposes a 6 -acre "wet" spreading area in the Etiwanda Creek
Spreading Grounds above Summit Avenue and 8 acres of "wet" spreading area below Summit
Avenue. Based on the proposed 14 acres and a 3 feet /day recharge rate, the estimated recharge
capacity is 42 acre - feet /day.
2. Possible Additional Water Conservation in San Sevaine Basin No. 5
For purposes of spreading local drainage and storm flows for water conservation purposes
only, all or a portion of the estimated recharge capacity necessary to percolate the "average
annual runoff' can be transferred to San Sevaine Basin No. 5. The use of Basin No. 5
will satisfy the major needs for the proposed BOR Project and the spreading of local storm
flow by the Flood Control District.
Based on the theoretical analysis provided for the BOR Project, the Etiwanda and San
Sevaine watershed area above San Sevaine Basin No. 5 will provide an estimated 12,500
acre - feet /year of "average annual conservable runoff". If it is assumed all the runoff will
be percolated in Basin No. 5, and a 3 feet /day recharge rate is used, then it will take
approximately 70 days to percolate the runoff (12,500 AF - 60 AC x 3 FT /D).
The above analysis does not take into consideration the needs of MWD or CBMWD to
spread imported water.
3 -26
It is assumed the spreading of local storm flow will occur in the October to March period
and the spreading of imported water will take place in the April to October period,
although some overlapping can and does occur.
The proposed use of the Etiwanda Spreading Grounds by MWD and CBMWD for
spreading imported water is discussed below.
3. Use of Meandering Stream(s) or Ponds in a Potential
Golf Course or Development for Water Spreading
This analysis is based on a potential meandering low flow stream along a golf course with
2 to 4 acres of ponding area above Wilson Avenue.
If a stream 10 feet in width and 9,500 feet long is assumed, along with 4 acres of ponds,
then, theoretically, approximately 360 acre -feet of local drainage flows can be recharged
over a 30 -day period. If it is assumed only 5 feet of the 10 -foot wide stream is wet at all
times, then the recharge reduces to approximately 300 acre -feet over a 30-day period.
If 8 acres ( "wet" bottom area) of water conservation ponds are provided in the existing
Etiwanda Spreading Grounds south of Wilson Avenue then approximately 480 acre -feet of
water can be recharged over a 30 -day period during the wet months (November thru
March).
If the 8 acres are used for spreading imported water during the 7 -month (210 days) from
April thru October, then approximately 3,360 acre - feet /year can be spread. If 10 acres
of spreading ponds are provided, the recharge capacity increases to 4,200 acre - feet /year.
If the spreading of imported water can be extended to 270 days (9 months), the recharge
capacity will increase to approximately 5,400 acre - feet /year (10 AC x 2 FT /D x 270 days
= 5,400 AF/YR).
0 Use of Etiwanda Spreading Grounds by CBMWD
A turnout into the Etiwanda Spreading Grounds was constructed by MWD from its Rialto Feeder
located on Wilson Avenue. The turnout was constructed on a trial basis as a demonstration project
for the future Conjunctive Use Program.
3 -27
CBMWD (Chino Basin Watermaster) has been using the turnout for spreading both "replenishment"
water and "cyclic storage" water. During the water year ended June 30, 1987, CBMWD spread
approximately 1,850 acre -feet of replenishment water and approximately 3,020 acre -free of cyclic
storage water during the months September thru March.
The total 4,870 acre -feet spread during the year ended June 30, 1987, occurred over a 7 -month
period (210 days ±) for an average recharge of approximately 23 acre - feet /day.
According to Don Peters, the Watermaster Administrator, the existing Etiwanda Creek Spreading
Grounds has a recharge capacity of approximately 40 acre - feet /day.
The possibility of transferring the water spreading activity to San Sevaine Basin No. 5 was discussed
with Don Peters. He advised the Watermaster would not object to the use of Basin No. 5 as a
replacement area as long as the basin had the necessary recharge capacity. CBMWD presently
spreads water in the Etiwanda Spreading Grounds under an agreement with the Flood Control
District.
There is a turnout from the MWD Feeder in the San Sevaine Spreading Grounds above Summit
Avenue (24th Street). Water from this turnout can be conveyed to Basin No. 5 and /or Basin Nos.
2 thru 4. There is a 48 -inch turnout proposed from the Etiwanda Channel into Basin No. 5. The
existing turnout flows into the Etiwanda Spreading Grounds can be extended to basin No. 5 by
utilizing the future Etiwanda Channel and the proposed 48 -inch pipe into Basin No. 5.
Based on a 30 -acre basin bottom use in Basin No. 5 (50% of 60 acres using a wet and dry cycle)
and a 2 feet /day recharge rate over a 7 -month period (210 days), approximately 12,600 acre -
feet /year can be spread in Basin No. 5. During years of normal or less than normal rainfall, it may
be possible to extend the use of the basin for spreading imported water beyond the 7 -month (210
days) period (April thru October).
la
4d1 Although the present use of the Etiwanda Spreading Grounds by CBMWD can be transferred to
Basin No. 5, a conflict and /or a lack of capacity may arise due to the potential use of Basin No. 5
by MWD.
3 -28
The proposed use of the San Sevaine Basins (Nos. 2 thru 5) by MWD is discussed below. Due
to the possible use of Basin No. 5 by both MWD and CBMWD, the retention of some water
spreading capacity in the Etiwanda Spreading Grounds is recommended.
CBMWD does not have a set spreading capacity need per year. The water spreading need is based
on the need to spread replenishment water for various water users in Chino Basin and for spreading
desired cyclic storage water.
Rather than assume all water spreading by MWD will occur in Basin No. 5, it may be necessary
to use Basin Nos. 2 and 4 for MWD use for spreading imported water also.
O Future Use of Etiwanda Spreading Grounds by MWD
The proposed use by MWD for spreading imported water in the Etiwanda Spreading Grounds
and San Sevaine Basin is based on the following reports:
"Chino Basin Groundwater Storage Program,
Appendix- Project A ", by CDM, Inc., dated March, 1983
"Draft Environmental Impact Report, Chino Basin
Groundwater Storage Program ", by MWD dated June, 1988
A letter was written to the Developer Consortium on February 14, 1989, indicating the
possibility of MWD using Basin No. 5 for spreading imported water.
According to the above referenced EIR, MWD proposes to spread 6,900 acre - feet /year in the
Etiwanda Spreading Grounds. Additionally, MWD proposes to spread 6,200 acre - feet /year in
the San Sevaine Basins. If Basin No. 5 is used for the total water spreading activity by MWD,
then a total of 13,100 acre - feet /year would be spread in Basin No. 5 by MWD.
Based on a 30 -acre "wet" basin bottom (50% of 60 acres on a wet -dry cycle) and a 2 foot /day
recharge rate over a 7 -month period (210 days), the theoretical recharge capacity is 12,600 acre-
feet/year, which is slightly less than the 13,100 acre - feet /year proposed by MWD as indicated
above. Additionally, some compensation has to be made for disking and scarifying the basin
and other operational factors that may limit the optimum spreading operation.
3 -29
If a 9 -month (270 days) period for spreading imported water is assumed, as proposed by MWD,
the potential recharge capacity in Basin No. 5 would increase to approximately 16,200 acre -
feet /year (30 AC x 2 FT /D x 270 days = 16,200 AF /YR).
It may be necessary to use San Sevaine Basins (Nos. 2 thru 4) in addition to Basin No. 5 for
MWD spreading of imported water.
O Summary
1. The additional "water conservation" storage available in San Sevaine Basin No. 5 would
offset the loss of the Etiwanda Spreading Grounds as far as the BOR Project is concerned.
However, both MWD and CBMWD propose to use the Etiwanda Spreading Grounds to
spread imported water.
2. MWD proposes to spread 6,900 acre - feet /year in the Etiwanda Spreading Grounds and
6,200 acre - feet /year in the San Sevaine Basins, for a total of 13,100 acre - feet /year.
Based on a 50% basin bottom use, Basin No. 5 can theoretically handle approximately
12,600 acre - feet /year during a 210 -day (7 months) period.
3. CBMWD is presently using the Etiwanda Spreading Grounds for spreading cyclical storage
water and replenishment water for recharge purposes. CBMWD spread approximately
4,870 acre -feet in the 1987 water year, at an average of 23 acre - feet /day.
If a 25 acre - feet /day recharge capacity is maintained in the Etiwanda Creek area, then a
"wet" bottom area of 13 acres at a minimum will be necessary. It will require 20 acres
of "wet" bottom area to maintain the existing 40 acre - feet /day presently available in the
Etiwanda Spreading Grounds.
If a constant use of Basin No. 5 by MWD to spread 13,100 acre - feet /year is assumed,
there will be no available recharge capacity in Basin No. 5 for CBMWD.
4. It is possible to design San Sevaine Basins (Nos. 2 thru 4) for spreading of imported
water.
3 -30
If 20 acres of Basins (Nos. 2 thru 4) are used for spreading water, the recharge capacity
will be approximately 4,200 acre - feet /year based on a 50% bottom use and a 2l0 -day
period. If a 270 -day period is assumed, the recharge capacity is 5,400 acre - feet /year.
5. It is possible to "piggy - back "some imported water on local flow storage in Basin No. 5
due to the proposed storage volume (736 acre -feet) that will be available. The reverse is
true for local drainage flows. However, storing water for future percolation increases
evaporation losses.
The following outlines the advantages and disadvantages identified by FWLS for water conservation
facilities located in the San Sevaine Spreading Grounds or the San Sevaine Basins:
4
4
4
3 -31
4.
SAN SEVAINE BASINS
ADVANTAGES
• Provides flexibility for development of • Provides flexibility for
the North Etiwanda Spreading Grounds for development of the South Etiwanda
residential or recreational uses while Spreading Grounds for a joint use
incorporating water conservation within detention basin /equestrian center or
land use constraints a single debris basin
• San Sevaine Basin location for operation • San Sevaine Basin location and
of water percolation beds versus elevation will likely minimize
Etiwanda Spreading Grounds minimizes water losses due to wind generated
visual and operational impacts on evaporization in comparison to the
residential area Etiwanda Spreading Grounds location
DISADVANTAGES
• Elimination or reduction of the Etiwanda • Combining storm water detention
Spreading Grounds will involve a and conservation operations in
more complex design and approval San Sevaine Basins is less desireable
process than individual facilities from an
0 & M standpoint
• The District's BOR Project includes
water conservation in both San Sevaine • Overall reduction in potential water
Basin 5 and Etiwanda Spreading Grounds spreading capabilities
3 -32
ETIWANDA SPREADING GROUNDS
NORTH AND OR SOUTH OF WILSON AVENUE
ADVANTAGES
• Perpetuates existing conditions which • Maximizes potential water spreading
minimizes public agency processing and capabilities in the area
approvals required
• In conformance with the Districts BOR
Project
DISADVANTAGES
• Removes and /or reduces flexibility for • Eliminates potential District revenue
land development and recreational uses from sale of property, golf course
in the existing spreading grounds lease, and /or property taxes
3 -33
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SECTION 4
CATEGORICAL PROJECT SOLUTIONS
4.1 SBCFCD 1983 Master Plan Solution
In 1983, the San Bernardino County Flood Control District adopted a Master Plan for construction of
the Day and San Sevaine Creek Channel systems. The plan was prepared by Bill Mann & Associates
and included Day Creek Channel, Spreading Grounds, and Debris Dam; Wineville Basin; and Lower
Etiwanda Creek Channel in the Day Creek system. The San Sevaine Creek system included San Sevaine
Creek Channel and Debris Dam, Jurupa Basin, San Sevaine Basins Expansion, and Etiwanda Basins.
The Master Plan facilities for Day Creek Channel, (from Wineville Basin upstream) Debris Dam, and
Spreading Grounds have been constructed. Master Plan facility construction in the San Sevaine Creek
Channel system was recently completed on the segment between Foothill Boulevard and Victoria Street.
The September 1989 Fee Ordinance, adopted by the City's of Rancho Cucamonga, Fontana and the
County of San Bernardino, estimated the cost of the San Sevaine Creek Channel system to be
$46,088,407. This cost does not include Etiwanda Channel between I -15 and San Sevaine Basin 5,
which was not included in the 1983 Master Plan Facility Solution. The Etiwanda Creek Channel (from
I -15 to debris basin) and debris dam portion is indicated to cost $10,502,408. FWLS estimated the cost
of this portion in December 1989 to be $20,000,000. This includes additional costs for expanding
existing Etiwanda Creek, from Victoria Street to San Sevaine Basin 5, a non jurisdictional debris basin
in lieu of a dam, a bridge at future Wilson and Summit Avenue, and a diversion system to San Sevaine
Basin No. 5:
0 Channel Facilities
- High velocity rectangular concrete channel from San Sevaine Basin No. 5 area to
debris dam.
0 Debris Facilities
- State jurisdictional debris dam on upstream side of LADWP utility corridor.
4 -1
rn
O Detention Facilities
- San Sevaine Basin No. 5 for runoff mitigation in Upper and Lower San Sevaine
Watershed, and permanent peak flow reduction for downstream facilities.
0 Water Conservation Facilities
- Etiwanda Spreading Grounds, San Sevaine Basins 1 -5, San Sevaine Wash Spreading
Grounds, Victoria Basin, and Rich Basin.
4.2 Modified SBCFCD 1983 Master Plan
Since the adoption of the 1983 Master Plan, a number of changes or factors in our environment have
come into play. Accordingly, modifications to the 1983 Master Plan have been proposed along with
other alternatives for project solutions. The factors behind the modifications and actions taken are
generally:
O SBCFCD 1986 Hydrology Data and Methodology
O "Etiwanda North Specific Plan" for development in the Upper Etiwanda /San Sevaine Watersheds
O Runoff mitigation requirements
O FEMA regulations /criteria for Day Creek
O EPA legislation with more direct involvement
O Alluvial fan habitat value
O The use of armorflex for channel lining in California
The modified Master Plan solution outlined below is essentially the substitution of a limited velocity
concrete channel for a high velocity concrete channel, and the substitution of a debris "basin" for a
debris "dam ". And, the addition of runoff mitigation for the Upper Etiwanda Watershed. The
estimated cost of the channel and debris facilities is $25,000,000 in comparison to $20,000,000 for the
1983 Master Plan as updated by FWLS.
0 Channel Facilities
- Modified existing trapezoidal concrete channel from Victoria Street to San Sevaine
Basin No. 5 area.
- Limited velocity rectangular concrete channel from San Sevaine Basin No. 5 area to
debris basin.
4 -2
O Debris Facilities
- Non jurisdictional debris basin on upstream side of LADWP utility corridor.
O Detention Facilities
- San Sevaine Basin No. 5 for runoff mitigation for Upper and Lower San Sevaine
Watershed, and permanent peak flow reduction for downstream facilities.
- Detention basin in Lower and /or Upper Etiwanda Spreading Grounds at Wilson Avenue
for runoff mitigation in Upper Etiwanda Watershed for City of Rancho Cucamonga
Master Plan Storm Drains XIV -3, XIV -8g, XIV -9f, and XIV -23.
O Water Conservation Facilities
- San Sevaine Basin No. 5 with options for additional capacity in San Sevaine Basins
2, 3 & 4; and the proposed detention basins located in the Etiwanda Spreading
Grounds.
4.3 Environmental Levee Solution
The environmental levee solution provides a vegetated armorflex lined levee system to capture and
guide Etiwanda Creek runoff and debris flows down to Wilson Avenue. Essentially this solution
preserves the existing SBCFCD right -of -way area upstream of Wilson Avenue, and the alluvial fan
scrub habitat within that area. This solution also includes a dual function debris /detention facility at
Wilson Avenue which is considered by certain parties to be necessary for preservation of the alluvial fan
habitat. That is, with a debris basin located at the mouth of the canyon, the natural cycle of water and
debris flows would be interrupted. This, in effect, could result in the eventual loss of the habitat. The
reader is referred to the Draft EIR for the Etiwanda North Specific Plan for more detail on this matter.
q
The reach downstream of Wilson Avenue would be a vegetated parabolic armorflex channel in this
solution. The estimated cost of the channel, levees, and dual debris /detention facility is $20,000,000.
O Channel Facilities
- Modified existing trapezoidal concrete channel from Victoria Street to San Sevaine
Basin No. 5 area.
- Parabolic armorflex channel from San Sevaine Basin No. 5 area to Wilson Avenue.
4 -3
- Vegetated concrete armorflex lined levees from Wilson Avenue to the LADWP utility
corridor.
O Debris Facilities
- Jurisdictional dual function debris dam /detention basin on the upstream side of Wilson
Avenue.
O Detention Facilities
- San Sevaine Basin No. 5 for runoff mitigation for Upper and Lower San Sevaine
Watershed, and permanent peak flow reduction for downstream facilities.
- Dual function state jurisdictional debris dam /detention basin on the upstream side of
Wilson Avenue.
O Water Conservation Facilities
- San Sevaine Basin No. 5 with options for additional capacity in San Sevaine Basins
2, 3 & 4.
4.4 Composite Concrete /Armorflex Channel Solution
The composite concrete and armorflex channel solution is intended to address the District's apparent
uncertainty over the use of armorflex channel lining on steeper grades. Accordingly, this solution
proposes armorflex downstream of Wilson Avenue where the average design slope is approximately
3.5 %. Upstream of Wilson Avenue, this solution includes a limited velocity concrete channel where this
average design slope is approximately 6 %.
It should be noted that the Proposed Factor of Safety Design Methodology, by Simons, Li & Associates
and referenced herein, takes into account the design slope, and slope is not a limiting design factor. The
related limiting factor is the design velocity which cannot exceed the experimental value of
approximately 20 feet per second (fps). The armorflex sections were sized accordingly and resulted in
average velocities of 18.3 fps below and 18.6 fps above Wilson Avenue respectively. In light of this
data, the District's uncertainty over the use of armorflex on steeper slopes appears to be unwarranted.
44 4-4
vs
The reach upstream of Wilson Avenue in this solution would be a limited velocity concrete channel
from Wilson Avenue upstream to a debris basin at the canyon mouth area. The estimated cost of the
channel and debris facilities is $25,000,000.
O Channel Facilities
- Modified existing trapezoidal concrete channel from Victoria Street to San Sevaine
Basin No. 5 area.
- Vegetated parabolic concrete armorflex channel from San Sevaine Basin No. 5 area to
Wilson Avenue.
- Limited velocity rectangular concrete channel from Wilson Avenue to a debris basin on
the upstream side of LADWP utility corridor.
O Debris Facilities
- Non jurisdictional debris basin on upstream side of LADWP utility corridor.
O Detention Facilities
- San Sevaine Basin No. 5 for runoff mitigation in Upper and Lower San Sevaine
Watershed, and permanent peak flow reduction for downstream facilities.
- Detention basin in Lower and /or Upper Etiwanda Spreading Grounds at Wilson Avenue,
for runoff mitigation in Upper Etiwanda Watershed for City of Rancho Cucamonga
Master Plan Storm Drains XIV -3, XIV -89, XIV -9f, and XIV -23.
O Water Conservation Facilities
- San Sevaine Basin No. 5 with options for additional capacity in San Sevaine Basins
2, 3 & 4; and the proposed detention basins located in the Etiwanda Spreading
Grounds.
4.5 All Armorflex Channel Solution
The all armorflex solution is a slightly modified version of the North Etiwanda Land Owners
Consortium's Flood Control Sub - Committee preferred alternative. The modification is simply a change
in the cross section of Etiwanda Creek below Wilson Avenue from a trapezoidal to a parabolic shape.
This section provides a higher design factor of safety and was recommended by Simons, Li &
Associates. This solution includes a short reach of concrete channel in the furthest downstream reach.
4 -5
1
The reach from Wilson Avenue to a debris basin at the canyon mouth remains as a parabolic armorflex
Lined channel.
As outlined below, the detention facility for runoff mitigation in the Etiwanda Watershed involves the
diversion of Etiwanda Creek flows into an expanded San Sevaine Basin No. 5. This solution results in
an incremental construction cost savings of approximately $4,000,000 over the next least
expensive alternative. However, the adjacent Intex 6 acre commercially zoned parcel would need to be
acquired or a land exchange consummated.
The estimated construction cost of the channel and debris facilities for this solution is $24,000,000.
O Channel Facilities
- Modified existing trapezoidal concrete channel from Victoria Street to San Sevaine
Basin No. 5 area.
- Vegetated parabolic concrete armorflex channel from San Sevaine Basin No. 5 area to
debris basin.
O Debris Facilities
- Non jurisdictional debris basin on upstream side of LADWP utility corridor.
O Detention Facilities
- San Sevaine Basin No. 5 for runoff mitigation in Upper and Lower San Sevaine
Watershed, and permanent peak flow reduction for downstream facilities.
- Diversion of Etiwanda Creek flows into an expanded San Sevaine Basin No. 5 for
runoff mitigation in Upper Etiwanda Watershed. Basin expansion includes the
acquisition or land swap for adjacent Intex 6 acre site.
O Water Conservation Facilities
- San Sevaine Basin No. 5 with options for additional capacity in San Sevaine Basins
2,3and4.
.4
4-6
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