APPENDIX D Project Feasibility Report

APPENDIX D Project Feasibility Report

Laguna Canyon Creek Erosion Control and Restoration Project:

PPRROOJJEECCTT FFEEAASSIIBBIILLIITTYY RREEPPOORRTT AANNDD AALLTTEERRNNAATTIIVVEESS AANNAALLYYSSIISS Technical Memorandum Final January 2014

Prepared for:

City of Laguna Beach 505 Forest Avenue

Laguna Beach, CA 92651

Prepared by:

RBF Consulting 14725 Alton Parkway

Irvine, CA 92618

Project Feasibility Report and Alternatives Analysis

January 2014 i RBF Consulting

Suggested citation: RBF Consulting. 2014. Laguna Canyon Creek Erosion Control Project: Project Feasibility Report and Alternatives Analysis. Prepared by RBF Consulting, Irvine, California for the City of Laguna Beach.


January 2014 ii RBF Consulting

Table of Contents 1 INTRODUCTION ........................................................................................................ 1 1.1 Project Overview ............................................................................................................ 1 1.2 Study Goal and Objectives .............................................................................................. 3 2 EXISTING STUDIES ................................................................................................... 4 2.1 Initial Study and Conceptual Restoration Plan for Laguna Canyon Creek by PCR

Services Corporation, October 8, 2003 (PCR, 2003)........................................................ 4 2.2 FEMA Flood Insurance Study, Orange County, California and Incorporated Areas,

December 3, 2009 (FEMA, 2009) ................................................................................... 4 2.3 J.P. Kapp Studies ............................................................................................................ 4 3 ALTERNATIVES ANALYSIS .................................................................................... 5 3.1 Formulation of Conceptual Plans .................................................................................... 5 3.1.1 Flood Conveyance and Protection Goals ......................................................................... 5 3.1.2 Habitat Enhancement ...................................................................................................... 6 3.1.3 Initial Formulation of Plans ............................................................................................ 7 3.2 Alternatives Evaluation ................................................................................................... 9 3.2.1 Alternative 1 – Gabion Channel Lining ........................................................................... 9 3.2.2 Alternative 2 – Lowered Parking Lot and Gabion Channel Lining ................................. 14 3.2.3 Alternative 3 – Relocated Public Parking and Channel Widening .................................. 18 3.2.4 Alternative 4 – Cantilevered Parking and Gabion Channel Lining ................................. 22 3.2.5 Alternative 5 – Corps Preferred Alternative: Armorflex Lining with Restorative

Herbaceous Planting ..................................................................................................... 26 3.3 Summary and Conclusions ............................................................................................ 30


January 2014 iii RBF Consulting

Tables

Table 3-1. Laguna Canyon FEMA FIS Flow Rates ........................................................................ 6

Table 3-2. Opinion of Probable Project Cost for Alternative 1 ..................................................... 11





Table 3-7. Alternative Analysis Summary .................................................................................... 31

Figures

Figure 1-1. Vicinity Map ................................................................................................................. 2

Figure 1-2. Effective FEMA Special Flood Hazard Mapping at Project Site ................................. 3

Figure 3-1. Alternative No. 1 – Gabion Channel Lining ............................................................... 12

Figure 3-2. Alternative No. 2 – Lowered Parking Lot and Gabion Channel Lining ..................... 16

Figure 3-3. Alternative No. 3 – Relocated Public Parking and Channel Widening ...................... 20

Figure 3-4. Alternative No. 4 – Cantilevered Parking and Gabion Channel Lining ..................... 24

Figure 3-4. Alternative No. 5 – Armorflex with Restorative Herbaceous Planting ..................... 28

Appendices

Appendix A. HEC-RAS Cross Sections

Hydraulic Calculations

Alternative 5 – 30% Design Plans ........................................................................... 32

Technical Studies (Separate Reports/Letters)

Delineation of Jurisdictional Waters for the Laguna Canyon Creek Erosion Protection Project,

City of Laguna Beach, Orange County, California. RBF Consulting. April 17, 2012.


January 2014 1 RBF Consulting

1 INTRODUCTION

1.1 Project Overview

The City of Laguna Beach owns a parcel of land at 20612 Laguna Canyon Road that includes the City Animal Shelter and the Pacific Marine Mammal Center. Laguna Canyon Creek is a major stream corridor which traverses the parcel from north to south. Other improvements on the site include paved and unpaved parking lots and two bridge crossings, a temporary wooden pedestrian bridge and a permanent concrete bridge used for drive access directly to the buildings. The location of the site with the stream area highlighted is shown on the Vicinity Map, Figure 1-1. On-going erosion of the channel banks along the creek has threatened the animal shelter facility and is undermining the paved parking lot. The City has installed interim erosion control measures along the channel banks including loose and grouted riprap in an effort to protect the adjacent improvements. The creek now incorporates a variety of partially improved channel linings and sections along the property. The non-cohesive nature of the miscellaneous improvements has resulted limited flood conveyance capacity, erosion and sedimentation problems, and a highly disturbed stream corridor environment. Exotic and/or invasive species have also encroached within the channel limits. Laguna Canyon Creek has been identified as having regional significance in that it is adjacent to the Laguna Coast Wilderness Park and can provide a wildlife corridor for sensitive species to and from Aliso and Wood Canyons Regional Park (PCR, 2003). The channel predominately consists of native wetland habitat such as cattail, willow and herbaceous species. This vegetation thrives in wet environments and has restricted the conveyance capacity of the creek. Laguna Canyon Creek is also a regional flood control system, designated as Orange County Flood Control District (OCFCD) Facility No. I02. The creek has a tributary watershed area of approximately 9.2 square miles (5,890 acres) at the outlet to the Pacific Ocean. At the project site, the watershed has a tributary area of approximately 5.5 square miles (3,500 acres). Along the creek through the study reach, Laguna Canyon has a natural floodplain that generally parallels Laguna Canyon Road. The small channel section of the creek does not provide adequate flood conveyance during large storm events, and much of the canyon has been identified as a special flood hazard area (Zone AE, 100-year floodplain with base flood elevations) on the effective Federal Emergency Management Agency (FEMA) Flood Insurance Rate Maps (FIRMs). This reach also includes an adopted regulatory floodway (Figure 1-2). The City has undertaken this study in an effort to identify opportunities for long-term erosion protection for the site and opportunities for increased flood conveyance and enhancement of the stream corridor habitat.



Figure 1-1: Vicinity Map.



Figure 1-2: Effective FEMA Special Flood Hazard Mapping at Project Site.

1.2 Study Goal and Objectives

The creek has experienced significant erosion of the channel banks which has jeopardized the adjacent improvements including a parking lot, two bridge crossings, and the City Animal Shelter and Pacific Marine Mammal Center. The City has recently provided interim protection through the placement of loose riprap. While this interim measure will provide temporary erosion protection, a long-term solution is needed to address the problems at the site including, erosion control, flood capacity, and habitat restoration. The City of Laguna Beach has undertaken this study in an effort to identify opportunities for long-term erosion protection and habitat enhancement for the site. The specific objectives of the study include:

1. Compile and review previous studies completed for the watershed including conceptual restoration plans, hydrology and hydraulic studies, floodplain mapping, and others.

2. Prepare an environmental assessment of the project site to identify jurisdictional waters and complete a biological assessment.

3. Assess the hydrology and hydraulics of the creek at the project site. 4. Identify potential concepts for long-term erosion control along the creek. 5. Perform a screening analysis of the potential concepts and identify alternatives for

evaluation. 6. Prepare an alternative evaluation including the preparation of conceptual layouts and

sections, cost estimates, environmental impacts and advantages/disadvantages of each. 7. Prepare a technical memorandum and graphic exhibits to summarize the results of the

alternative evaluation.



2 EXISTING STUDIES

Numerous planning and engineering studies have been completed for the Laguna Canyon watershed over the last 10-years. The following summarizes the studies that were review as part of this alternatives analysis.

2.1 Initial Study and Conceptual Restoration Plan for Laguna Canyon Creek by PCR Services Corporation, October 8, 2003 (PCR, 2003).

This study was prepared by PCR and Aspen Environmental Services for the City to prepare an initial study and conceptual restoration plan for Laguna Canyon Creek from the El Toro Road and Highway 133 intersection south to the City Dog Park, a reach of approximately 4,000 lineal feet. The plan was prepared to develop a reasonable set of actions to restore native habitat within the existing constraints of the study reach. The assessment area was divided into seven (7) reaches. The City’s Animal Shelter and the Pacific Marine Mammal Center are located along Reach 6. The recommendations for Reach 6 generally include widening the channel and providing a stream meander. The existing vehicle bridges would be maintained, and the pedestrian bridge eliminated. The parking is proposed to be re-configured, but no details are provided for the new parking or access to the existing vehicle bridges.

2.2 FEMA Flood Insurance Study, Orange County, California and Incorporated Areas, December 3, 2009 (FEMA, 2009).

The Flood Insurance Study (FIS) for Orange County included detailed studies for Laguna Canyon. The report identified the peak discharges for storm events having a 10, 2, 1, and 0.2 percent chance of occurrence in any given year (10-, 50-, 100-, and 500-year recurrence intervals, respectively). Detailed hydraulic models were also prepared to delineate the floodplain limits and water surface profiles for each of the storm events. Digital copies of the HEC-RAS hydraulic computer models used to develop the water surface profiles have also been obtained and were used as a basis for this study.

2.3 J.P. Kapp Studies

Numerous studies have been completed by J.P. Kapp Civil Engineers regarding the stream erosion and potential flooding at the City’s animal shelter. These studies include an assessment of floodplain impacts associated with the animal shelter building expansion, as well as preliminary hydraulic analysis for various channel erosion control concepts. Field surveyed topography was prepared for J.P. Kapp and the City in February 2009 by Ware Enterprises, Inc. The topographic mapping included detailed information for the entire Animal Shelter site, and the creek adjacent to the Pacific Marine Mammal Center. The topography was used in conjunction with City’s LiDAR information to prepare the hydraulic analysis for the existing conditions and evaluated alternatives.



3 ALTERNATIVES ANALYSIS

3.1 Formulation of Conceptual Plans

The goal of the project is to identify improvements to mitigate problems resulting from erosion, increase flood conveyance along Laguna Canyon Creek adjacent to the project site, and improve habitat function and value. The primary criterion for the plan development is erosion control. The other critical factors to be considered in the screening and evaluation process include flood conveyance, habitat restoration, parking, access, and environmental criteria. The design of a successful sustainable solution must consider and balance the numerous competing interests. The factors to be considered as part of the project include: § Erosion Control – Protect existing banks and adjacent facilities from erosion and bank

failure § Flood Capacity – Increase the creek capacity to accommodate larger events and reduce

the flood hazards § Vegetation/Wildlife – Remove non-native species and restore native habitat to improve

habitat values and functions and facilitate flood conveyance § Aesthetics – Improve the channel aesthetics to appropriate levels in conjunction with

stakeholder/community values § Access / Parking – Improve or maintain current levels of staff and public access and

parking § Regulatory Permitting – Obtain regulatory approvals from the U.S. Army Corps of

Engineers, California Department of Fish and Wildlife, San Diego Regional Water Quality Control Board, and California Coastal Commission

§ California Coastal Commission – Restore the channel so that it promotes wetlands and Environmentally Sensitive Habitat as defined by the Commission

§ CEQA –By using an environmentally superior alternative, pursuant to Coastal Commission guidance, the project would be Categorically Exempt under CEQA

Potential concepts were generated with the assistance of the City of Laguna Beach, and input from previous studies and City Council meetings. Restoration ecologists with the Corps also provided guidance in spring 2013. The concepts considered a range of options, and no constraints were placed on the initial formulation of plans. The initial conceptual alternatives underwent a screening process where those alternatives that were clearly not feasible were eliminated from further consideration. For the remaining alternatives, a more detailed evaluation was prepared to make an assessment of the plan feasibility and cost.

3.1.1 Flood Conveyance and Protection Goals

Laguna Canyon Creek is a major water course that drains a watershed area of approximately 3,500 acres (FEMA 2009) at the project site. The watershed has been studied as part of FEMAs FIS for Orange County and Incorporated Areas. This included the identification of flow rates for various return frequencies and the establishment of base flood elevations and a regulatory floodway along the creek. The project site is approximately 0.6 miles downstream of El Toro Road. Based on a review of the watershed areas, the flow rates in the FEMA FIS at approximately 400 feet downstream of El



Toro Road best represent the estimated flows at the project site. The watershed area and flow rates along the creek in the FIS are summarized in Table 3-1.

Table 3-1. Laguna Canyon FEMA FIS Flow Rates

Location Drainage Area

Peak Discharges in cubic feet per second (cfs)

Percent chance of occurrence

10% (10-Yr)

2% (50-Yr)

1% (100-Yr)

0.2% (500-Yr)

At El Toro Road 3.9 720 1,800 2,500 4,200

Approx 400’ downstream of El Toro Road 5.4 1,100 2,600 3,700 6,300

Approx 1.7 miles downstream of El Toro Road 7.3 1,200 2,900 4,100 7,000

A preliminary estimate of the existing channel capacity through the site was prepared using the HEC-RAS computer program. The model was developed using the 2009 field surveyed topography prepared by J.P. Kapp, and the City’s available LiDAR mapping. The two bridges on the site were added to the model to evaluate the creek capacity. The capacity was determined as the flow through the creek prior to the water surface elevations reaching the adjacent buildings. The building elevations were based on the 2009 topography. The results of the analysis identified an existing capacity of approximately 600 cfs. At this flow rate, ponding behind the existing drive access bridge results in water surface elevations equal to the finished floor at the Animal Shelter. 3.1.1.1 Flood Protection Goals

Flood protection goals for the project were identified in conjunction with the City. The overall goal is to increase the capacity of the project reach to match the capacity of the channel segment near the City’s dog park located just downstream of the project. Downstream of the dog park the creek is conveyed to an underground reinforced concrete box culvert (RCB). The design capacity of the RCB is 1,800 cfs. A HEC-RAS model was developed for the downstream reach near the Dog Park to identify the channel conveyance capacity. The model was based on the FEMA model that was used as a basis for the effective floodplain and regulatory floodway. The existing bridge was added to the FEMA model. The bridge geometry was based on information from plans and field visits. The results of the analysis identified a channel capacity of approximately 2,000 cfs prior to flows overtopping the channel banks. Based on these downstream constraints, the flood protection objective of the project is to increase the channel capacity through the project site to 1,800 to 2,000 cfs.

3.1.2 Habitat Enhancement

A functional biological assessment was prepared for the project site using the California Rapid Assessment Method (CRAM). The CRAM is a wetland assessment tool that has been based on the US Environmental Protection Agency’s (USEPA) Level 1-2-3 Framework for ambient



wetland monitoring and assessment.1 The overall goal of CRAM is to “Provide rapid, scientifically defensible, standardized, cost-effective assessments of the status and trends in the condition of wetlands and the performance of related policies, programs and projects throughout California.”2 CRAM is designed to cost-effectively assess the performance of wetland and riparian restoration projects, mitigation projects, and the status and trends of ambient conditions within watersheds, regions of the State, and for the State as a whole. The use of CRAM for ambient monitoring helps wetland managers and scientists quantify the relative influence of anthropogenic stress, management actions, and natural disturbance on the spatial and temporal variability in reference conditions. This information can then be used in the design, management, and assessment of projects. Specific applications of CRAM could include: § assessments of impacted wetlands to help determine appropriate mitigation measures; § preliminary assessments of wetland conditions and stressors to determine the need for

intensive monitoring; § evaluation of wetland project performance under the Coastal Zone Management Act,

Section 1600 of the California State Fish and Game Code, Sections 401 and 404 of the Clean Water Act, and local government wetland regulations; and

§ assessment of restoration or mitigation progress relative to ambient conditions, reference conditions, and expected ecological trajectories.

A CRAM analysis was prepared for the study reach shown on Figure 1-1. The analysis evaluates four (4) attributes to estimate the health of the stream corridor. The attributes are based on an evaluation of the buffer and landscape context, hydrology, physical structure, and biotic structure. The overall assessment area (AA) score for the reach was determined to be 43.75%, which is considered poor. A detailed discussion of the CRAM analysis is included in the Technical Study, Delineation of Jurisdictional Waters for the Laguna Canyon Creek Erosion Protection Project, City of Laguna Beach, Orange County, California, prepared by RBF Consulting. One of the objectives of the project is to improve the habitat value of the creek, and each of the alternatives was evaluated to consider the potential changes to the CRAM score as a result of the improvements in the Technical Study. This evaluation is summarized in the alternative analysis and will be used to identify the habitat enhancement potential for each of the alternatives.

3.1.3 Initial Formulation of Plans

During the initial plan formulation process, both structural and non-structural plans were considered. Structural plans include physical improvements to address the identified problems within the study reach. Non-structural plans include floodplain management, maintenance activities, and purchase of flood or erosion-prone areas to prevent repetitive losses. A summary of the concepts reviewed included:

Channelization. Variations of this plan include the construction of a uniform channel section through the site. The channel section would be configured as a concrete-lined trapezoidal or

1 Using CRAM to Assess Wetland Projects As an Element of Regulatory and Management Programs,

Technical Bulletin, California Wetlands Monitoring Group, October 13, 2009. 2 CRAM Users Manual, Version 5.0.2, September 2008.



rectangular section. This plan does not meet many of the project objectives and was therefore eliminated from additional consideration.

Upstream Detention Basin(s). This alternative would consider construction of one or more off-site detention basins to reduce flows to non-erosive velocities and lower base flood elevations. The design, permitting, and construction of a detention basin to eliminate erosion and flooding at the project site is a regional application that must be developed in coordination with the entire watershed. Therefore, this plan was eliminated from additional consideration.

Gabion Channel Lining. This plan would provide bank and invert protection to eliminate erosion and provide some channel widening to increase capacity. The existing drive bridge would be maintained, and a new footbridge would be installed. This concept has the ability to meet many of the project objectives and was carried forward for more detailed evaluation.

Lowered Parking Lot and Gabion Channel Lining. This plan is similar to the gabion channel lining, except that the existing public parking lot would be lowered and reconstruction to provide additional flood conveyance. This plan has the ability to meet many of the project objectives and was carried forward for more detailed evaluation.

Relocated Public Parking and Channel Widening. This plan would eliminate the existing public parking adjacent to Laguna Canyon Road and replace it at the paved parking lot near the Alternative Sleeping Location and the Dog Park. The existing parking would be re-graded to a widened channel system and planted with native vegetation. Gabion bank protection would be provided along the east bank adjacent to the Animal Shelter and Pacific Marine Mammal Center for erosion control. This concept has the ability to meet many of the project objectives and was carried forward for more detailed evaluation.

Cantilevered Parking and Gabion Channel Lining. This plan incorporates widening the existing channel with a gabion channel lining and cantilevering the parking lot over the widening channel. A reinforced concrete box culvert would be added adjacent to the existing drive access bridge to accommodate the increased channel capacity. This concept has the ability to meet many of the project objectives and was carried forward for more detailed evaluation.

Armorflex Lining with Restorative Herbaceous Planting. This plan recommended by Corps Restoration Ecologists incorporates widening the existing channel with Armorflex reinforcement mats in order to promote the conveyance of stormwater through the project site by creating increased channel capacity. The existing pedestrian bridge would be relocated next to the existing drive bridge serving the Pacific Marine Mammal Center. South of the access bridge along the eastern slope of the existing channel would be additional slope protection measures (riprap with willow cuttings) as well as bendway weirs which would direct flows back toward the thalweg of the channel. This concept has the ability to meet many of the project objectives and was carried forward for more detailed evaluation.

Installation of Porous Paving. The existing asphalt concrete parking lots would be reconstructed with porous paving (concrete pavers) to reduce runoff from the site. The installation of porous paving would reduce the runoff from the project site and improve the water quality. However, the site runoff is insignificant compared to the overall watershed runoff, and this plan would not provide any real increase in erosion control or flood protection. The concept of concrete pavers will be considered for alternatives where the asphalt concrete paving is proposed to be replaced, but is not considered a standalone project.



Channel Widening. Increase the channel width through the site based on the concept from the “Initial Study and Conceptual Restoration Plan for Laguna Canyon Creek.” The channel would be widened adjacent to Laguna Canyon Road, and the parking lots eliminated. This plan is similar to the Relocated Public Parking and Channel Widening and will be considered as part of that alternative.

Vegetation Removal and Continuous Maintenance. This plan would incorporate more frequent maintenance of the channel to remove vegetation and sediment prior to the flood season. The vegetation and sediment removal would increase the channel capacity through the site. This alternative would result in potentially more erosion through the site as a result increased channel flow velocities. The plan does not meet the primary objective as a stand-alone project. Additional and more frequent maintenance of the channel needs consideration with all alternatives.

Floodplain Retreat. Under this plan, the existing structures in the floodplain and subject to potential damage from erosion would be removed and relocated to another site. This plan is not considered as a practical alternative and was therefore eliminated from consideration.

3.2 Alternatives Evaluation

Four of the alternatives from the preliminary formulation of plans passed the initial screening assessment and are evaluated in additional detail in this section.

Alt. No. 1: Gabion Channel Lining Alt. No. 2: Lowered Parking and Gabion Channel Lining Alt. No. 3: Relocated Public Parking and Channel Widening Alt. No. 4: Cantilevered Parking and Gabion Channel Lining Alt. No. 5: Armorflex Lining with Restorative Herbaceous Planting

The alternative analysis included in this technical memorandum includes; a description of the proposed project; graphic exhibit and typical section; rough construction cost estimate; and general notes for each of the identified alternatives. The evaluation includes a discussion of the alternatives’ success in meeting the project objectives, environmental impacts, habitat enhancement potential, and possible advantages and discharges. A preliminary hydraulic analysis of each alternative was prepared to determine the hydraulic performance and assess potential channel capacity and floodplain impacts associated with the alternative. The analysis was prepared using the Army Corps of Engineers HEC-RAS River Analysis System computer program.

3.2.1 Alternative 1 – Gabion Channel Lining

3.2.1.1 Description

Alternative No. 1 includes the construction of gabion channel linings to limit erosion and increase the channel capacity. Stepped gabions would be placed on the channel banks to approximately the same height (8-feet) as the current banks. The channel would be slightly widened to have a 20-foot base width, and the invert would be graded to remove existing sediment that has been deposited. Rock filled gabions would be installed on the channel invert to provide additional erosion protection from the northern limits through the drive access bridge. The gabion bank protection would extend along the east bank adjacent to the Pacific Marine Mammal Center. No gabions would be required on the west bank downstream of the drive access bridge. Non-native



vegetation would be removed from the channel and riprap areas and replaced with native species. The existing pedestrian bridge would be removed and replaced with the longer bridge to span the new channel width. The drive access bridge will be protected in place. For this alternative, the following major improvements and/or modifications are proposed:

1. Install gabion bank protection along the entire east bank, and west bank through the City’s Animal Shelter. Widen the channel to a 20-foot base width;

2. Install gabions on the channel invert from the northern limit through the drive access bridge;

3. Replace the existing pedestrian bridge to accommodate the new channel width; and, 4. Remove non-native vegetation and replace with native materials.

3.2.1.2 General notes

This alternative is the least invasive and results in the fewest impacts to the site. The plan would increase the creek capacity from a flow rate of about 600 cfs to approximately 1,300 cfs. The project would not result in any impact to public or staff parking or access at the site. Environmental enhancement would be accomplished through the removal of non-native species and the replacement with native plant materials. The net area of enhancement would not be significantly increased from the current area. The change in CRAM score is anticipated to be minimal with this alternative. The overall aesthetics of the stream would be improved with the removal of existing loose and grouted riprap and the installation native plantings. 3.2.1.3 Advantages

This alternative is the second least expensive of all the alternatives. It has the smallest overall impact and would result in the least disruption during construction. It meets many of the project objectives including; erosion control, no net loss of parking, and minor enhancement to the stream habitat. 3.2.1.4 Disadvantages

This alternative has the lowest stream capacity of the alternatives carried forward for evaluation, and does not meet the minimum channel capacity objective of 1,800 cfs. It also has the least potential for environmental enhancement. It has also been expressed by the regulatory agencies in past pre-application meetings that there are concerns regarding the strength of the gabion baskets being prone to breaking down over the course of time and exposing banks to potential erosion. 3.2.1.5 Opinion of probable project cost

The total project cost for Alternative 1 is approximately $336,700. The results of the preliminary cost estimate are shown on Table 3-2.



Table 3-2. Opinion of probable project cost for Alternative 1

Line Item Description Unit Quantity Unit Cost Cost

Category Cost

1.0 Site Preparation Work $69,0001.1 Mobilization & bonding (5%) LS 1 $15,000 $15,0001.2 Clearing and grubbing LS 1 $10,000 $10,0001.3 Diversion and Control of Water LS 1 $15,000 $15,0001.4 Remove Existing Pedestrian Bridge EA 1 $4,000 $4,0001.5 Remove Grouted/Loose Riprap CY 300 $50 $15,0001.6 Erosion Control/SWPPP EA 1 $10,000 $10,0002.0 General Civil and Structural $209,1502.1 Excavation CY 520 $20 $10,4002.2 Gabion Bank Protection CY 430 $300 $129,0002.3 Reno (Gabion) Mattress CY 65 $150 $9,7502.4 Pedestrian Bridge EA 1 $60,000 $60,0003.0 Landscape and Irrigation $14,6003.1 Planting / Seeding SF 4,800 $2 $9,6003.2 Temporary Irrigation EA 1 $5,000 $5,000

$292,750$43,913

$336,700Contingencies (15%)

Total project cost

Construction cost subtotal



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3.2.2 Alternative 2 – Lowered Parking Lot and Gabion Channel Lining

3.2.2.1 Description

Alternative No. 2 includes the same improvements as Alternative No. 1, except the stepped gabions would be placed on the channel banks to approximately 8-feet on the east bank and 5-feet on the west bank. The public parking adjacent to Laguna Canyon Road would be re-graded to lower the parking lot elevation by approximately 3 feet. The paved section is proposed to be replaced with concrete pavers to reduce the site runoff and provide water quality benefits. The lowered parking lot would function as a flood overbank during moderate storm events, with flow velocities of approximately 5-7 feet per second. This would increase the overall flow capacity along the project reach. The existing drive access bridge would remain in place. Graded ramps would be provided from Laguna Canyon Road down to the lowered parking area, and from the parking area up to the existing bridge. The maximum slope of the ramps would not exceed 10%. The new pedestrian bridge would be located next to the existing drive bridge, and an access ramp provided to the pedestrian bridge in accordance with ADA requirements. New sidewalk and curb and gutter would be installed along Laguna Canyon Road in front of the Pacific Marine Mammal Center to provide additional on-street parking. Non-native vegetation removal and installation of native plantings would be similar to Alternative No. 1. For this alternative, the following major improvements and/or modifications are proposed:



3. Re-grade and lower the existing public parking area by approximately 3 feet; 4. Replace AC paving with concrete pavers; 5. Replace the existing pedestrian bridge to accommodate the new channel width; 6. Install new sidewalk and curb and gutter along Laguna Canyon Road; and, 7. Remove non-native vegetation and replace with native materials.


This alternative has a larger impact and cost compared to Alternative No. 1. The plan would increase the creek capacity from a flow rate of about 600 cfs to approximately 1,500 cfs. This increase is only 200 cfs more than Alternative No. 1. Due to the graded slopes to lower the parking area, the project will result in the loss of public parking spaces. It is anticipated that 3 paved spaces and 4 unpaved spaces would be lost as a result of the grading. Five (5) of these space are proposed to be recaptured by the installation of sidewalk and curb and gutter and on-street parking along Laguna Canyon Road. Construction of the sidewalk will need to be coordinated with the relocation of an existing Edison utility pole. For this project, it is assumed that the utility pole will be relocated by others. Environmental enhancement would be accomplished through the removal of non-native species and the replacement with native plant materials. The net area of enhancement would not be significantly increased from the current area. The change in CRAM score is anticipated to be minimal with this alternative. The overall aesthetics of the stream would be improved with the removal of existing loose and grouted riprap and the installation native plantings. 3.2.2.3 Advantages

This plan meets the project objective of erosion control. It provides additional flow capacity compared to Alternative No. 1, but does not meet the flood conveyance goals. It can provide



water quality benefits through the removal and replacement of existing AC pavement with porous pavement or concrete pavers. 3.2.2.4 Disadvantages

Alternative No. 2 provides only a minor increase in flood conveyance capacity compared to Alternative No.1, and falls short of the minimum flood conveyance objective of 1,800 cfs. It has a higher cost than Alternative No. 1 and includes a loss of parking spaces. The impact during construction is more significant and will result in a longer construction duration. 3.2.2.5 Opinion of probable project cost

The total project cost for Alternative 2 is about $522,700. The results of the preliminary cost estimate are shown on Table 3-3.



Category Cost

1.0 Site Preparation Work $89,3001.1 Mobilization & bonding (5%) LS 1 $20,000 $20,0001.2 Clearing and grubbing LS 1 $15,000 $15,0001.3 Diversion and Control of Water LS 1 $15,000 $15,0001.4 Remove Existing Pedestrian Bridge EA 1 $4,000 $4,0001.5 Remove Grouted/Loose Riprap CY 300 $50 $15,0001.6 Remove Paving SF 8,000 $1 $8,0001.7 Remove Concrete Strip CY 2 $150 $3001.6 Erosion Control/SWPPP EA 1 $12,000 $12,0002.0 General Civil and Structural $350,6502.1 Excavation CY 1,920 $20 $38,4002.2 Gabion Bank Protection CY 390 $300 $117,0002.3 Reno (Gabion) Mattress CY 65 $150 $9,7502.4 Pedestrian Bridge EA 1 $60,000 $60,0002.5 Porous Paving SF 8,000 $14 $112,0002.6 Pedestrian Access Ramp EA 1 $5,000 $5,0002.7 Concrete Sidewalk SF 1,000 $6 $6,0002.8 Concrete Curb and Gutter LF 125 $20 $2,5003.0 Landscape and Irrigation $14,6003.1 Planting / Seeding SF 4,800 $2 $9,6003.2 Temporary Irrigation EA 1 $5,000 $5,000

$454,550$68,183

$522,700Total project cost

Construction cost subtotal Contingencies (15%)






3.2.3 Alternative 3 – Relocated Public Parking and Channel Widening

3.2.3.1 Description

Alternative No. 3 generally includes the removal of the existing public parking spaces adjacent to Laguna Canyon Road, and the widening of the creek to expand into this area. This plan is similar to the concept for Reach 6 in the “Initial Study and Conceptual Restoration Plan for Laguna Canyon Creek” report (PCR, 2003). The eliminated parking is proposed to be relocated to the existing City parking lot near the Alternative Sleeping Location and the Dog Park, and through on-street parking along Laguna Canyon Road. Approximately 5 on-street parking spaces will be provided, and the existing City parking lot is proposed to be re-paved with permeable concrete pavers. The existing pedestrian bridge and drive access bridge would be removed. Vehicular access to the animal shelter and mammal center would be provided by a new access road from the existing parking lot along the east bank of the creek. The channel work includes the construction of stepped gabions to be placed on the east channel bank to an approximate height of 8-feet. The gabions would extend along the entire east bank adjacent to the City’s Animal Shelter and the Pacific Marine Mammal Center and provide space and bank protection for the new access road. No gabions would be required on the west bank through this reach. The existing parking will be removed and the area re-graded as a terraced overbank for flood conveyance and establishment of riparian vegetation. A meandering pedestrian trail is proposed to be installed through the terraced overbank area. A low-flow bridge crossing will be included along the trail to provide pedestrian access to the shelter and mammal center from Laguna Canyon Road. Non-native vegetation would be removed from the channel and replaced with native species. For this alternative, the following major improvements and/or modifications are proposed:

1. Remove existing public parking lot, pedestrian bridge, and drive access bridge; 2. Install gabion bank protection along the entire east bank; 3. Install new 12-foot wide access road from the existing City parking lot; 4. Re-grade the existing public parking lot as a terraced floodplain overbank area; 5. Install new sidewalk and curb and gutter along Laguna Canyon Road; 6. Reconstruct the existing City parking lot with permeable concrete pavers; 7. Provide signage and stripping for new parking area; 8. Install riparian vegetation in graded area; 9. Construct meandering pedestrian trail and low water crossing; and, 10. Remove non-native vegetation and replace with native materials.


This alternative has the largest impact area, but provides the greatest channel capacity and the most potential for habitat enhancement. The plan would increase the creek capacity to a flow rate of approximately up to 2,000 cfs. This alternative is in compliance with the recommendations in the Laguna Canyon Creek Conceptual Restoration Plan (PCR, 2003). Environmental enhancement would be accomplished through the removal of non-native species and the replacement with native plant materials and the development of approximately 10,000 square feet of riparian vegetation. The change in CRAM score is anticipated to be the greatest with this alternative and could be potential significant. Construction of the sidewalk will need to be coordinated with the relocation of the existing Edison utility pole. For this project, it is assumed that the utility pole will be relocated by others. 3.2.3.3 Advantages

This alternative meets the objectives for erosion control, flood conveyance, and habitat enhancement. The main advantages of this alternative are the increases in the creek capacity and



the ability to provide significant stream restoration along the project reach. Another significant benefit of this alternative is the improved parking, access, and safety associated with moving the parking to the existing City lot. Access to the parking lot would now be provided by the existing bridge at the City’s Dog Park. This bridge has better flow capacity and access from Laguna Canyon Road is greatly improved compared to the current conditions with appropriate turn outs and acceleration/deceleration lanes. The plan is also in general conformance with previous recommendations for this reach. 3.2.3.4 Disadvantages

The primary disadvantage is the loss of the existing parking lot. The parking spaces would be relocated to the existing City parking lot which could result in conflicts with other land uses. 3.2.3.5 Opinion of probable project cost

The total project cost for Alternative No. 3 is roughly $550,900. The results of the preliminary cost estimate are shown on Table 3-4.



Category Cost

1.0 Site Preparation Work $117,3001.1 Mobilization & bonding (5%) LS 1 $15,000 $15,0001.2 Clearing and grubbing LS 1 $20,000 $20,0001.3 Diversion and Control of Water LS 1 $15,000 $15,0001.4 Remove Existing Pedestrian Bridge EA 1 $4,000 $4,0001.5 Remove Existing Drive Bridge EA 1 $20,000 $20,0001.7 Remove Grouted/Loose Riprap CY 300 $50 $15,0001.7 Remove Paving SF 16,000 $1 $16,0001.8 Remove Concrete Strip CY 2 $150 $3001.9 Erosion Control/SWPPP EA 1 $12,000 $12,0002.0 General Civil and Structural $306,7602.1 Excavation CY 2,600 $20 $52,0002.2 Gabion Bank Protection CY 300 $300 $90,0002.3 Access Road w/Porous Paving SF 2,100 $14 $29,4002.4 Repave w/Porous Paving SF 8,000 $14 $112,0002.5 Concrete Sidewalk SF 2,160 $6 $12,9602.6 Concrete Curb and Gutter LF 270 $20 $5,4002.7 Pedestrian Trail and Low Water Xing EA 1 $5,000 $5,0003.0 Landscape and Irrigation $55,0003.1 Planting / Seeding SF 20,000 $2 $40,0003.2 Temporary Irrigation EA 1 $15,000 $15,000

$479,060$71,859








3.2.4 Alternative 4 – Cantilevered Parking and Gabion Channel Lining

3.2.4.1 Description

Alternative No. 4 generally includes the same improvements as Alternative No. 1, except the channel would be widened an additional 15-feet to a 35-foot base width, and the parking lot would be cantilevered over the widened channel area. This would increase the overall flow capacity along the project reach. The existing drive access bridge would remain in place, and a reinforced concrete box culvert would be added adjacent to the bridge to convey flows from the creek widening. Some re-grading of the stream downstream of the drive access bridge is required where the RCB culvert is installed. A new pedestrian bridge would be constructed at the location of the current bridge to span the wider creek. Non-native vegetation removal and installation of native plantings would be similar to Alternative No. 1. The re-graded area of the channel downstream of the drive access bridge would be planted with native vegetation. For this alternative, the following major improvements and/or modifications are proposed:



3. Construct a reinforced concrete 15-foot wide deck span over the widening creek; 4. Construct a double barrel 7’ x 7’ reinforced concrete box culvert at the drive access

bridge; 5. Replace the existing pedestrian bridge to accommodate the new channel width; and, 6. Remove non-native vegetation and replace with native materials.


This alternative has the largest cost as a result of the cantilevered parking deck. The plan would increase the creek capacity to a flow rate of over 2,000 cfs, which exceeds the flood conveyance objective. The project will not result in the loss of public parking spaces by cantilevering the parking over the widened channel. Environmental enhancement would be accomplished through the removal of non-native species and the replacement with native plant materials. The net area of enhancement would not be significantly increased from the current area, and could potentially be reduced due to the cantilevered parking over the channel section. The change in CRAM score is anticipated to be minimal with this alternative. The overall aesthetics of the stream would be improved with the removal of existing loose and grouted riprap and the installation native plantings. 3.2.4.3 Advantages

This plan meets the objective of erosion control and exceeds the minimum flood conveyance goal of 1,800 cfs. The plan would also maintain parking and access similar to the current conditions. 3.2.4.4 Disadvantages

Alternative No. 4 has the highest cost of all the alternatives. Environmental enhancement potential is lower than other less expensive alternatives due to potential shading and topographic conditions.



3.2.4.5 Opinion of probable project cost

The total project cost for Alternative 4 is approximately $714,200. The detailed results of the preliminary cost estimate are shown on Table 3-5.



Category Cost

1.0 Site Preparation Work $103,3001.1 Mobilization & bonding (5%) LS 1 $40,000 $40,0001.2 Clearing and grubbing LS 1 $15,000 $15,0001.3 Diversion and Control of Water LS 1 $15,000 $15,0001.4 Remove Existing Pedestrian Bridge EA 1 $4,000 $4,0001.5 Remove Grouted/Loose Riprap CY 300 $50 $15,0001.6 Remove Paving SF 2,000 $1 $2,0001.7 Remove Concrete Strip CY 2 $150 $3001.6 Erosion Control/SWPPP EA 1 $12,000 $12,0002.0 General Civil and Structural $503,1502.1 Excavation CY 1,120 $20.00 $22,4002.2 Gabion Bank Protection CY 430 $300 $129,0002.3 Reno (Gabion) Mattress CY 65 $150 $9,7502.4 Pedestrian Bridge EA 1 $60,000 $60,0002.5 Dbl 7' x 7' RCB LF 20 $1,600 $32,0002.5 Concrete Parking Deck SF 2,000 $125 $250,0003.0 Landscape and Irrigation $14,6003.1 Planting / Seeding SF 4,800 $2 $9,6003.2 Temporary Irrigation EA 1 $5,000 $5,000

$621,050$93,158








3.2.5 Alternative 5 – Corps Preferred Alternative: Armorflex Lining with Restorative Herbaceous Planting

3.2.5.1 Description

Alternative 5 includes the construction of Armorflex reinforcement mats on the channel side slopes in order to limit erosion and increase channel capacity. This alternative was designed by RBF in concert with Corps restoration ecologist, Dave Derrick. The existing drive access bridge would remain in place and a poured-in-place concrete transition structure added to the existing RCB to convey flows from the creek widening. A new pedestrian bridge would be constructed immediately adjacent to the access road which currently serves the Pacific Marine Mammal Center. Some re-grading of the stream downstream of the drive access bridge is proposed to enhance downstream vegetation. Non-native vegetation removal and the introduction of herbaceous native plantings are proposed both upstream and downstream of the access bridge. The toe of the eastern slope adjacent to the Pacific Marine Mammal Center will incorporate riprap protection (covered with earthen fill) bioengineered with willow cuttings for further support. In addition, bendway weirs are proposed at this location to direct flows away from the slope and toward the thalweg of the channel. A few larger tree species are also proposed for the top of slope upstream of the access bridge. The re-graded area of the channel downstream of the drive access bridge would be planted with native vegetation. For this alternative, the following major improvements and/or modifications are proposed:

1. Install Armorflex reinforcement bank protection along the west and east banks immediately north of the access bridge and new pedestrian bridge; 2. Remove and replace the existing pedestrian bridge to be adjacent to the existing access

bridge; 3. Install riprap protection with willow cuttings at the toe of the eastern slope south of the

Pacific Marine Mammal Center; 4. Install bendway weirs at the toe of the riprap protection to direct flows away from slope

and toward thalweg of the channel; 5. Streambank recontouring with understory planting south of the access bridge on the west

slope; 6. Remove non-native vegetation and replace with native materials (i.e. herbaceous plants

and some larger canopy tree species). 3.2.5.2 General notes

The plan would increase the creek capacity to a flow rate of 915 cfs, which partially meets the flood conveyance objective. Environmental enhancement would be accomplished through the removal of non-native species and the replacement with native plant materials. The net area of enhancement would not be significantly increased from the current area; although streambank recontouring south of the access bridge along the west slope would offer the ability of incorporate topographic complexity thereby increasing plant species diversity. The change in CRAM score is anticipated to increase given the proposed physical and biological constraints of the project site. It is expected that this alternative would enhance CRAM attribute scores for Hydrology (i.e. Hydroperiod or Channel Stability), Physical Structure (structural path richness and topographic complexity), and Biotic Structure (Horizontal Intersection and Zonation). The overall aesthetics of the stream would be improved with the removal of existing loose and grouted riprap and the installation native plantings.



3.2.5.3 Advantages

This alternative is the least expensive of all the alternatives. This plan meets the objective of erosion control. Recontouring the streambank south of the access bridge directs flows away from the slope and towards the thalweg of the channel. In addition, restoration planting with native species would also be accommodated with the project design. 3.2.5.4 Disadvantages

Alternative No. 5 does not fully meet the flood protection goals. 3.2.5.5 Opinion of probable project cost

The total project cost for Alternative 5 is approximately $289,300. The detailed results of the preliminary cost estimate are shown on Table 3-6.



Category Cost

1.0 Site Preparation Work $70,4001.1 Mobilization & bonding (5%) LS 1 $15,000 $15,0001.2 Clearing and grubbing LS 1 $15,000 $15,0001.3 Diversion and Control of Water LS 1 $15,000 $15,0001.4 Remove Existing Pedestrian Bridge EA 1 $4,000 $4,0001.5 Remove Grouted/Loose Riprap CY 300 $25 $7,5001.6 Remove Paving SF 1,600 $1 $1,6001.7 Remove Concrete Strip CY 2 $150 $3001.6 Erosion Control/SWPPP EA 1 $12,000 $12,0002.0 General Civil and Structural $166,5902.1 Excavation CY 590 $20 $11,8002.2 Armorflex Reinforcement Mats SF 1,920 $20 $38,4002.3 Toe Riprap CY 70 $75 $5,2502.4 Bendway Weirs EA 3 $400 $1,2002.5 Retaining Wall SF 610 $50 $30,5002.6 Transition Structure EA 1 $15,000 $15,0002.7 Pedestrian Bridge EA 1 $60,000 $60,0002.8 Paving Replacement SF 1,480 $3 $4,440

3.0 Landscape and Irrigation $14,6003.1 Planting / Seeding SF 4,800 $2 $9,6003.2 Temporary Irrigation SF 1 $5,000 $5,000

$251,590$37,739



PROTECT EXISTING TREES(WHERE POSSIBLE)

ARTICULATING CONCRETEBLOCK (ACB) MATTRESS

EXISTINGPARKING LOT

BUILDING

PLANTED TERRACE

TREEWELL

SYCAMORE TREES(AT INTERVALS)

8’EXISTINGSURFACE

3’ CONCRETERETAINING WALL

ANCHOR4’

Modified Alternative No. 1c

TALL HERBACEOUSHERBACEOUSSPECIES

EXISTING PARKING LOT(PROTECT IN PLACE)

EXISTING TREES(PROTECT IN PLACE)

ACB BANKS

ANIMALSHELTER PACIFIC MARINE

MAMMAL CENTER

LAGUNA CREEK

PARKING LOT NEARALTERNATIVE

SLEEPING LOCATION

RELOCATE EXISTINGPEDESTRIAN BRIDGE

RIPRAP TOE PROTECTIONWITH CUTTINGS

ACCESS BRIDGE(PROTECT IN PLACE)

NATIVE PLANTING

STREAM BANK RECONTOURING AREAWITH PLANTING

BENDWAYWEIRS (3)

PLANTED TERRACE

CONCRETERETAINING WALL

LAGUNA CANYON CREEK EROSION CONTROL PROJECT

Alternative No. 5 Armorflex Liningwith Restorative Herbaceous Planting

20’

LAGUNA CANYON ROAD






3.3 Summary and Conclusions

An assessment of the preliminary alternatives in relation to the project goals and environmental impacts was prepared to systematically evaluate the alternatives. The primary goal of the project is erosion control, with increased flood conveyance and habitat restoration as major objectives. Additional objectives include; parking and access, channel aesthetics, and minimizing environmental impacts. Each of the five alternatives meets the project goal of providing erosion protection. A comparison of the alternatives including estimated cost and ability to meet the other objectives are summarized in Table 3-7. The preferred alternative preliminary 30% design included determining how much capacity could be achieved while not impacting the existing parking lot, and adjacent buildings and walkways. The preliminary design consists of a section varying base width from 12 to 15 foot wide and a total depth of 5 feet. The east bank of the channel will be lined with Armorflex with a 3 foot toe down and a 1.5:1 slope. The west bank of the channel will be lined with Armorflex and will include both a 1.5:1 slope and planting terrace with a 4.5 foot high retaining wall adjacent to the existing parking lot. The existing pedestrian bridge will be relocated adjacent to the existing RCB and will be approximately 5’ wide spanning approximately 31 feet. A 10 foot long transition structure will be constructed underneath the relocated pedestrian bridge and will convey flows from the creek widening underneath the drive access bridge. Recontouring of the creek will begin approximately 27 feet downstream of the bridge along the west bank and will widen the top bank from 18 feet to 55 feet at the southern limits of the project. The east bank will re-graded and a riprap toe and bendway weirs added to protect the bank from erosion. The supporting hydraulic design is included in Appendix A. Exhibit 1 in Appendix A displays the HEC-RAS cross section station numbers and their corresponding construction stations used to perform the hydraulic analysis. The improved channel can convey 915 cfs with velocities ranging from 5 feet per second to 9 feet per second around the existing RCB. Depth of flow in the creek ranges from 5.3 to 6.3 feet. Lower depths of flow are seen in the recontouring area south of the bridge where the creek will be widened. Flow through the channel was limited to 915 cfs due to the water surface elevation and elevation of the Laguna Beach Animal Shelter. About 10 feet south of the existing pedestrian bridge, the water surface elevation matched that of the front entrance into the animal shelter. Armorflex minimum slope requirements, existing improvements, and channel geometry prevent the channel from being widened further, upstream of the access bridge, thus limiting the maximum amount of flow through the channel. During low flow conditions, sediment will deposit between the bendway weirs, slowly directing flow back towards the thalweg of the creek. This will further protect the east bank and the Pacific Marine Mammal Center.

Laguna Canyon Creek Erosion Control Project Alternatives Analysis at the Animal Shelter


Table 3-7. Alternatives Analysis Summary

Alt No Description

Estimated Cost

Channel Capacity

Jurisdictional Impacts

Parking Compariso

n Enhancement

Potential Notes Gabion Channel Lining

1 § Gabion bank protection § Reno mattress on invert § Replace pedestrian bridge § Protect exist. parking and drive bridge

$336,700 1,300 cfs § 0.05 acres (ACOE) § 0.09 acres (CDFG) § 0.09 acres (CCC)

No change + 0.1 acres Δ CRAM = Minimal increase

§ Does not meet flood conveyance goal

§ Minimum enhancement potential

§ Lowest cost Lowered Parking Lot and Gabion Channel Lining

2 § Gabion bank protection § Reno mattress on invert § Lower public parking area § Install porous paving § Replace pedestrian bridge

$522,700 1,500 cfs § 0.05 acres (ACOE) § 0.12 acres (CDFG) § 0.12 acres (CCC)

Net Loss: 2 spaces

+ 0.1 acres Δ CRAM = Minimal increase

§ Does not meet flood conveyance goal

§ Loss of parking § Provides water quality

benefits Relocated Public Parking and Channel Widening

3 § Gabion bank protection-east bank § Remove public parking area § Remove ped. and drive bridge § Replace public parking at Dog Park lot § Install new access road § Extend Laguna Canyon Road sidewalk and

curb & gutter

$550,900 Up to 2,000 cfs

§ 0.05 acres (ACOE) § 0.13 acres (CDFG) § 0.08 acres (CCC)

Potential increase with off-street parking area and on-street parking

+ 0.5 acres Δ CRAM = potential significant increase

§ Meets flood conveyance goals

§ Greatest potential for restoration

Cantilevered Parking and Gabion Channel Lining 4 § Gabion bank protection

§ Reno mattress on invert § Cantilever public parking area § Install RCB culvert at drive bridge § Replace pedestrian bridge

$714,200 Over 2,000 cfs

§ 0.05 acres (ACOE) § 0.09 acres (CDFG) § 0.13 acres (CCC)

No change


§ Exceeds flood conveyance goals

§ Highest cost § Low potential

restoration ACOE Preferred Alternative: Armorflex Lining with Restorative Planting

5 § Armorflex Reinforced Mats § Install RCB culvert at drive bridge § Relocation of pedestrian bridge to be

adjacent to the access bridge § Restoration Planting § Bendway weirs to support channel

stability § Riprap protection and willow cuttings

915 cfs § 0.05 acres (ACOE) § 0.09 acres (CDFG) § 0.13 acres (CCC)

No change


§ Partially addresses flood conveyance goals

§ Good potential for restoration

§ Corps Preferred Alternative



APPENDIX A

HEC-RAS Cross Sections Hydraulic Calculations

Alternative 5 – 30% Design Plans

A CompanyBaker

HEC-RAS Version 4.1.0 Jan 2010

U.S. Army Corps of Engineers

Hydrologic Engineering Center

609 Second Street

Davis, California

X X XXXXXX XXXX XXXX XX XXXX

X X X X X X X X X X

X X X X X X X X X

XXXXXXX XXXX X XXX XXXX XXXXXX XXXX

X X X X X X X X X

X X X X X X X X X X

X X XXXXXX XXXX X X X X XXXXX

PROJECT DATA

Project Title: 8392-LC-HEC

Project File : 8392-LC-HEC.prj

Run Date and Time: 1/21/2014 1:10:02 PM

Project in English units

PLAN DATA

Plan Title: Plan 10

Plan File : h:\pdata\10108392\Calcs\Strmwater\Hydraulics\HEC-RAS\8392-LC-HEC.p10

Geometry Title: 8392-LC-PH2-ALT1

Geometry File : h:\pdata\10108392\Calcs\Strmwater\Hydraulics\HEC-RAS\8392-LC-HEC.g10

Flow Title : 8392-HEC-EX-SITE

Flow File : h:\pdata\10108392\Calcs\Strmwater\Hydraulics\HEC-RAS\8392-LC-HEC.f02

Plan Summary Information:

Number of: Cross Sections = 19 Multiple Openings = 0

Culverts = 0 Inline Structures = 0

Bridges = 1 Lateral Structures = 0

Computational Information

Water surface calculation tolerance = 0.01

Critical depth calculation tolerance = 0.01

Maximum number of iterations = 20

Maximum difference tolerance = 0.3

Flow tolerance factor = 0.001

Computation Options

Critical depth computed only where necessary

Conveyance Calculation Method: At breaks in n values only

Friction Slope Method: Average Conveyance

Computational Flow Regime: Mixed Flow

FLOW DATA

Flow Title: 8392-HEC-EX-SITE

Flow File : h:\pdata\10108392\Calcs\Strmwater\Hydraulics\HEC-RAS\8392-LC-HEC.f02

Flow Data (cfs)

River Reach RS 50-YR 500 1000 1500 2000

900 925 915

Laguna Canyon Reach1 1104 2538.7 500 1000 1500 2000

900 925 915

Boundary Conditions

River Reach Profile Upstream Downstream

Laguna Canyon Reach1 50-YR Normal S = 0.005 Normal S = 0.005

Laguna Canyon Reach1 500 Normal S = 0.005 Normal S = 0.005




GEOMETRY DATA

Geometry Title: 8392-LC-PH2-ALT1

Geometry File : h:\pdata\10108392\Calcs\Strmwater\Hydraulics\HEC-RAS\8392-LC-HEC.g10

CROSS SECTION

RIVER: Laguna Canyon

REACH: Reach1 RS: 1104

INPUT

Description:

Date: 01/22/2014 File name: Copy of 8392-LC-HEC.out Page 1

Station Elevation Data num= 75

Sta Elev Sta Elev Sta Elev Sta Elev Sta Elev

0 190 2.72 189.67 3.78 189.62 4.19 189.6 4.83 189.57

5.82 189.51 15.54 188.69 17.91 188.58 22.55 188.31 27.74 188

30.71 187.63 35.35 187.03 42.32 186.74 44.87 186.51 48.8 186.34

49.82 186.27 53.64 186.11 55.93 186 58.47 185.84 59.26 185.75

64.31 185.34 69.27 184.88 71.1 184.62 72.1 184.47 73.93 184.27

75.27 184.15 77.65 184.01 77.78 184 77.93 184 79.79 184

81.11 183.78 81.27 183.75 81.49 183.69 82 182 92 177

96.5 177 103 180 110 185 114 185.28 117.89 186

118.72 186 120.8 186.16 123.67 186.37 132.03 186.8 135.73 187.05

142.12 187.54 145.18 187.7 147.6 188 151.34 188.29 155.06 188.45

165.96 189.05 172.21 189.36 181.5 189.58 190.7 190 200.48 190

200.93 190.06 203.58 190.4 215.82 192 225.27 193.72 226.78 194

228.48 194.33 231.24 194.89 236.79 196 239.76 196.3 252.88 197.32

253.79 197.4 254.95 197.5 258.61 197.81 258.99 197.83 260.84 198

265.79 198.55 267.38 198.72 270.55 199.06 274.9 199.54 279.14 200

Manning's n Values num= 3

Sta n Val Sta n Val Sta n Val

0 .03 81.27 .05 120.8 .03

Bank Sta: Left Right Lengths: Left Channel Right Coeff Contr. Expan.

81.27 120.8 47.69 48.97 52.11 .1 .3

CROSS SECTION OUTPUT Profile #50-YR

E.G. Elev (ft) 188.19 Element Left OB Channel Right OB

Vel Head (ft) 1.67 Wt. n-Val. 0.030 0.050 0.030

W.S. Elev (ft) 186.52 Reach Len. (ft) 47.69 48.97 52.11

Crit W.S. (ft) 186.52 Flow Area (sq ft) 44.12 205.91 0.92

E.G. Slope (ft/ft) 0.016901 Area (sq ft) 44.12 205.91 0.92

Q Total (cfs) 2538.70 Flow (cfs) 321.84 2215.10 1.77

Top Width (ft) 81.69 Top Width (ft) 36.46 39.53 5.70

Vel Total (ft/s) 10.12 Avg. Vel. (ft/s) 7.29 10.76 1.91

Max Chl Dpth (ft) 9.52 Hydr. Depth (ft) 1.21 5.21 0.16

Conv. Total (cfs) 19527.6 Conv. (cfs) 2475.6 17038.5 13.6

Length Wtd. (ft) 48.82 Wetted Per. (ft) 36.59 44.32 5.71

Min Ch El (ft) 177.00 Shear (lb/sq ft) 1.27 4.90 0.17

Alpha 1.05 Stream Power (lb/ft s) 279.14 0.00 0.00

Frctn Loss (ft) 0.57 Cum Volume (acre-ft) 1.42 3.51 0.28

C & E Loss (ft) 0.20 Cum SA (acres) 0.69 0.58 0.34

Warning: The energy equation could not be balanced within the specified number of iterations. The program used critical depth

for the water surface and continued on with the calculations.

Warning: The velocity head has changed by more than 0.5 ft (0.15 m). This may indicate the need for additional cross sections.

Warning: The energy loss was greater than 1.0 ft (0.3 m). between the current and previous cross section. This may indicate the

need for additional cross sections.

Warning: During the standard step iterations, when the assumed water surface was set equal to critical depth, the calculated

water surface came back below critical depth. This indicates that there is not a valid subcritical answer. The program

defaulted to critical depth.

CROSS SECTION OUTPUT Profile #1500


Vel Head (ft) 1.25 Wt. n-Val. 0.030 0.050


Crit W.S. (ft) 184.10 Flow Area (sq ft) 12.12 158.26

E.G. Slope (ft/ft) 0.013212 Area (sq ft) 12.12 158.26

Q Total (cfs) 1500.00 Flow (cfs) 58.37 1441.63

Top Width (ft) 47.12 Top Width (ft) 15.49 31.63

Vel Total (ft/s) 8.80 Avg. Vel. (ft/s) 4.82 9.11

Max Chl Dpth (ft) 8.20 Hydr. Depth (ft) 0.78 5.00

Conv. Total (cfs) 13049.7 Conv. (cfs) 507.8 12542.0

Length Wtd. (ft) 48.88 Wetted Per. (ft) 15.57 36.35

Min Ch El (ft) 177.00 Shear (lb/sq ft) 0.64 3.59


















Frctn Loss (ft) 0.67 Cum Volume (acre-ft) 0.07 1.98

C & E Loss (ft) 0.11 Cum SA (acres) 0.19 0.52


Warning: The conveyance ratio (upstream conveyance divided by downstream conveyance) is less than 0.7 or greater than 1.4.

This may indicate the need for additional cross sections.

CROSS SECTION




INPUT

Description:



0 188.19 .18 188 1 187.94 1.8 187.81 5.25 187.4

7.99 187.07 8.94 186.96 8.97 186.95 9.19 186.92 13.99 186

15.5 186 19.88 185.91 23.15 185.85 24.19 185.82 27.09 185.73

37.34 185.45 41.32 185.42 53.63 185.2 58.53 185.14 63.51 185.05

68.97 184.92 80.81 184.72 84.53 184.6 87.34 184.5 96.06 184.13

97.72 184.06 98.27 184.05 99.8 184 102.16 184 103.63 184

109.12 184 112.76 184 136.09 183 137.51 182 138.72 181

139.89 180 141.09 179 142.31 178 147.72 176.42 153.69 178

155.14 179 156.51 180 157.73 181 158.77 182 160 183

162.01 184 166.68 184 168.81 184.1 175.67 184.43 187.25 184.94

197.64 185.42 211.07 186 214.7 186.28 214.75 186.28 238.4 188

247.87 188.63 251.1 188.83 258.57 189.3 269.58 190 280.33 191.79

281.47 192 283.27 192.3 290.03 193.41 293.62 194 297.08 194.63



0 .03 136.09 .05 162.01 .03


136.09 162.01 9.67 11.98 14.81 .1 .3

Blocked Obstructions num= 1

Sta L Sta R Elev

2.85 79.62187.6824











































Vel Head (ft) 1.87 Wt. n-Val. 0.050


Crit W.S. (ft) 182.38 Flow Area (sq ft) 83.28

E.G. Slope (ft/ft) 0.028656 Area (sq ft) 83.28

Q Total (cfs) 915.00 Flow (cfs) 915.00

Top Width (ft) 22.27 Top Width (ft) 22.27

Vel Total (ft/s) 10.99 Avg. Vel. (ft/s) 10.99

Max Chl Dpth (ft) 5.96 Hydr. Depth (ft) 3.74

Conv. Total (cfs) 5405.2 Conv. (cfs) 5405.2

Length Wtd. (ft) 11.98 Wetted Per. (ft) 25.80

Min Ch El (ft) 176.42 Shear (lb/sq ft) 5.77











CROSS SECTION


REACH: Reach1 RS: 1043_00

INPUT

Description: EX STA. 1043 = PH2-ALT1 STA. 1000.00



0 188.19 .18 188 1 187.94 1.8 187.81 5.25 187.4

7.99 187.07 8.94 186.96 8.97 186.95 9.19 186.92 13.99 186

15.5 186 19.88 185.91 23.15 185.85 24.19 185.82 27.09 185.73

37.34 185.45 41.32 185.42 73.96 185.42 98.46 184 132.73 183

134.57 183 136.39 183 138.29 182 140.04 181 141.86 180

143.18 179 144.42 178 148.27 176.29 155.27 176.29 158.27 178.29

163.27 178.29 163.27 182.79 204.34 185 219.61 186 232.47 187

259.86 188 280.84 188 281.02 188 288.66 190 296.17 191.79

297.31 192 299.11 192.3 305.87 193.41 309.46 194 312.92 194.63



0 .03 136.39 .05 163.27 .03


136.39 163.27 7.44 7.44 7.44 .1 .3


Sta L Sta R Elev Sta L Sta R Elev

131.38 134.57 187.682 2.85 73.96 187.682

















Warning: Divided flow computed for this cross-section.




Note: Hydraulic jump has occurred between this cross section and the previous upstream section.




















Note: Program found supercritical flow starting at this cross section.






















CROSS SECTION



INPUT




0 188.19 .18 188 1 187.94 1.8 187.81 5.25 187.4

7.99 187.07 8.94 186.96 8.97 186.95 9.19 186.92 13.99 186

15.5 186 19.88 185.91 23.15 185.85 24.19 185.82 27.09 185.73

37.34 185.45 41.32 185.42 73.96 185.42 118.32 184 132.01 183

133.85 183 134.93 183 135.05 181.26 142.55 176.26 154.55 176.26

157.55 178.26 162.55 178.26 162.55 182.76 164.89 184 209.94 185

223.45 186 236.2 187 261.22 188 282.2 188 282.37 188

290.01 190 300.76 191.79 301.9 192 303.7 192.3 310.46 193.41

314.05 194 317.51 194.63



0 .03 134.93 .05 162.55 .03


134.93 162.55 24.48 23.02 22.01 .1 .3



130.66 133.85 187.682 2.85 73.96 187.682



























































CROSS SECTION



INPUT




0 186.7 4.95 186 8.69 185.86 13.45 185.74 33.73 185.15

44.29 184.73 50.55 184.54 54.19 184.45 55.01 184.43 67.39 184.04

67.47 184.04 67.72 184.03 70.04 184 76.71 184 78.18 184

83.24 183.89 95.47 183.77 96.49 183.75 103.27 183.6 104.99 183.48

106.1 183.44 107.53 183.38 109.42 183.31 123.48 183.3 133.08 183.5

145.4 183.5 148.96 181.16 156.48 176.16 168.5 176.16 171.51 178.16

176.52 178.16 176.52 182.66 182.93 183.75 184.29 184 190.18 184

217.2 184.82 225.85 184.93 228.5 185.04 248.93 186 256.63 186.49

280.48 188 298.08 188 301.46 188 301.64 188 307.78 189.59

309.28 190 310.62 190.34 310.93 190.41 311.13 190.45 313.42 190.97

316.75 191.75 317.93 192 321.29 192.65 327.48 194 332.9 194.6

334.84 194.81



0 .03 145.4 .05 176.52 .03


145.4 176.52 16.6 16.32 16.12 .1 .3



133.08 145.4 187 0 103.27 186.701










































Crit W.S. (ft) Flow Area (sq ft) 140.27













CROSS SECTION



INPUT




0 190 .01 190 4.21 190 7.57 188.98 8.48 189.08

9.07 189.12 9.57 188.98 9.67 188.95 9.86 188.89 10.54 188.74

10.78 188.66 11.03 188.56 11.86 188.45 12.04 188.4 12.2 188.38

12.34 188.36 13.25 188.29 13.77 188 17.72 187.44 25.71 186.39

29.35 186 35.82 185.67 44.46 185.29 47.03 185.24 54.75 184.95

89.57 184.11 90.78 184.07 92.57 184 92.93 184 93.45 184

102.72 184 133.62 183.36 142.32 183.27 145.49 183.21 149.49 183

178.75 182 183.6 182 184.17 181.08 191.69 176.08 203.73 176.08

206.74 178.08 211.76 178.08 211.76 182.58 217.02 183.19 218.06 183.22

218.44 183.27 218.73 183.3 218.95 183.33 219.1 183.35 224.28 183.52

224.47 183.54 224.68 183.56 224.9 183.58 225.09 183.6 237.7 183.98

237.71 183.98 237.75 183.99 237.77 183.99 237.82 183.99 237.84 183.99

237.85 183.99 237.99 184 238.04 184 238.23 184 252.63 184.19

255.28 184.3 260.47 184.52 273.4 184.99 279.56 185.27 294.12 186

299.16 186.31 306.94 186.79 326.52 188 332.16 188 341.04 188

343.93 188 344.62 188 347.63 188.96 350.9 190 353.62 190.72

358.45 192 362.78 192.87 368.42 194 370.71 194.46 378.44 196

380.84 196 390.53 197.08 392.61 197.47 395.62 198 398.68 198.79

402.94 200



0 .03 183.6 .05 211.76 .03


183.6 211.76 9.82 9.73 10.94 .1 .3


Sta L Sta R Elev

21.99 104.62 190






































Crit W.S. (ft) Flow Area (sq ft) 1.75 137.88













CROSS SECTION



INPUT




0 190 .01 190 4.21 190 7.57 188.98 8.48 189.08

9.07 189.12 9.57 188.98 9.67 188.95 9.86 188.89 10.54 188.74

10.78 188.66 11.03 188.56 11.86 188.45 12.04 188.4 12.2 188.38

12.34 188.36 13.25 188.29 13.77 188 17.72 187.44 25.71 186.39

29.35 186 35.82 185.67 44.46 185.29 47.03 185.24 54.75 184.95

89.57 184.11 90.78 184.07 92.57 184 92.93 184 93.45 184

101.58 184 133.62 183.36 142.32 183.27 143.48 183 173.01 182

178.66 182 183.82 181.04 191.32 176.04 203.32 176.04 206.32 178.04

211.32 178.04 211.32 182.54 217.02 183.19 218.06 183.22 218.44 183.27

218.73 183.3 218.95 183.33 219.1 183.35 224.28 183.52 224.47 183.54

224.68 183.56 224.9 183.58 225.09 183.6 237.7 183.98 237.71 183.98

237.75 183.99 237.77 183.99 237.82 183.99 237.84 183.99 237.85 183.99

237.99 184 238.04 184 238.23 184 252.63 184.19 255.28 184.3

260.47 184.52 273.4 184.99 279.56 185.27 294.12 186 299.16 186.31

306.94 186.79 326.52 188 332.16 188 341.04 188 343.93 188

344.62 188 347.63 188.96 350.9 190 353.62 190.72 358.45 192

362.78 192.87 368.42 194 370.71 194.46 378.44 196 380.84 196

390.53 197.08 392.61 197.47 395.62 198 398.68 198.79 402.94 200



0 .03 178.66 .05 211.32 .03


178.66 211.32 21.71 21.7 21.98 .1 .3


Sta L Sta R Elev

21.99 100.73 190





Crit W.S. (ft) Flow Area (sq ft) 153.48 233.76 64.35













































CROSS SECTION



INPUT




0 190 .59 189.66 3.31 188 4.07 187.66 7.02 186

19.67 184.58 24.07 184 24.24 184 27.52 184 32.05 184

40.36 184 43.16 184 63.59 184 72.57 183.41 76.84 183.37

79.58 183 89.06 183.14 90.22 183.12 91.86 183.08 99.62 182.89

104.24 182.8 110.28 182.41 113.36 182.62 131.39 182.27 138.58 182.12

139.34 182.11 147.63 182 159.3 182 162.69 181 163.81 180.94

171.31 175.94 186.31 175.94 189.31 177.94 194.31 177.94 194.31 182.44

198.55 182.77 206.1 183.09 210.19 183.27 212.71 183.38 232.9 184

255.4 184.91 271.51 185.44 283.6 186 293.25 186.56 297.6 186.77

324.26 188 329.94 188 336.17 189.83 336.74 190 338.46 190.4

342.45 191.35 345.2 192 353.72 193.55 356.86 194 363.51 195.24

367.03 196 367.25 196 369.84 196.29 370.47 196.35 374.32 196.75

376.09 196.94 383.39 197.61 384.87 197.76 385.68 197.83 387.61 198

394.7 199.15 398.72 199.81 399.89 200



0 .03 159.3 .05 194.31 .03


159.3 194.31 10.41 8.81 7.37 .1 .3


Sta L Sta R Elev

110.28 140.66 190























































CROSS SECTION



INPUT




0 190 .59 189.66 3.5 188 4.07 187.66 6.9 186

19.67 184.58 24.07 184 24.24 184 27.52 184 32.05 184

40.36 184 44.78 184 48.59 184 59.37 183.54 62.32 183.51

67.77 183.47 72.57 183.41 76.84 183.37 89.06 183.14 90.22 183.12

91.86 183.08 99.62 182.89 104.24 182.8 113.36 182.62 131.39 182.27

138.58 182.12 139.34 182.11 145.08 182 147.69 181.5 148.48 181.54

153.81 180.9 161.33 175.9 176.38 175.9 179.39 177.9 184.41 177.9

184.41 182.4 198.55 182.77 206.1 183.09 210.19 183.27 212.71 183.38

227.82 184 229.51 184 230.37 184 230.74 184.01 255.4 184.91

271.51 185.44 283.6 186 293.25 186.56 297.6 186.77 324.26 188

329.94 188 336.17 189.83 336.74 190 338.46 190.4 342.45 191.35

345.2 192 353.72 193.55 356.86 194 363.51 195.24 367.03 196

367.25 196 369.84 196.29 370.47 196.35 374.32 196.75 376.09 196.94

383.39 197.61 384.87 197.76 385.68 197.83 387.61 198 394.7 199.15

398.72 199.81 399.89 200



0 .03 147.69 .05 184.41 .03


147.69 184.41 23.27 24.6 26.03 .1 .3


Sta L Sta R Elev

66.14 140.34 190


















































CROSS SECTION




INPUT




0 190 8.3 189 10.08 188 11.9 187 13.65 186

18.43 185 41.51 182.6 99.04 182.6 104.39 182 115.62 182.63

124.36 182.63 139.38 182.63 139.53 182 140.05 182 142.94 181.3

145.86 181.3 148.59 181 149.29 180.79 156.79 175.79 171.79 175.79

174.79 177.79 179.79 177.79 179.79 182.29 197.19 183 237.43 184

260.68 185 276.45 186 301.26 187 335.71 188 342.29 190

349.54 192 362.99 194 376.63 196 391.59 198 412.89 200



0 .03 145.86 .05 179.79 .03


145.86 179.79 13.79 10.22 6.16 .1 .3



41.51 99.04 190 115.62 124.36 190

























































CROSS SECTION




INPUT




0 190 .03 189.98 3.77 188 5.56 187.06 7.55 186

8.46 185.47 11.22 184 17.27 183.34 18.38 183.3 24.51 182.69

27.19 182.63 30.99 182.57 39.96 182.4 47.74 182.09 59.34 182.01

59.36 182.01 60.2 182 70.06 182 71.33 182 78.18 181.87

79.11 181.84 91.88 181.74 93.22 181.68 94.56 181.63 95.63 181.58

103.06 182.09 112.6 181.93 115.08 182 127.12 181.86 128.05 180.74

135.56 175.74 150.6 175.74 153.62 177.74 158.65 177.74 158.65 182.24

170.56 182.42 181.43 182.87 187.7 183.1 193.28 183.33 196.43 183.45

211.27 183.95 211.61 183.97 211.86 183.98 211.97 183.98 212.03 183.98

212.51 184 236.5 184.76 246.52 185.07 270.76 186 299.57 187.29

314.15 188 319.27 189.56 320.73 190 326.9 191.72 327.98 192

334.91 193.03 341.44 194 347.18 194.83 355.07 196 369.01 197.87

369.51 197.93 370.03 198 370.1 198 371.72 198 374.04 198

374.75 198 376.94 198 377.21 198 379.02 198 379.07 198

379.39 198 379.41 198 379.67 198 379.69 198 380.45 198.1

381.35 198.19 382.45 198.39 383.37 198.52 386.39 199.08 391.31 200

391.32 200 391.33 200 391.34 200



0 .03 127.12 .05 158.65 .03


127.12 158.65 10.27 6.74 2.08 .1 .3



15.65 47.59 190 105.99 117.15 190

























































CROSS SECTION



INPUT




0 190 7.14 188 8.59 187 10.63 186 12.57 185

14.71 184 31.34 182 60.79 181 62.47 180.91 65 180.81

67.46 180.83 84 181 111.68 182 115.55 182 123.13 181.75

124.71 180.71 132.21 175.71 147.21 175.71 150.21 177.71 155.21 177.71

155.21 182.21 174.64 183 208.93 184 232.92 184.76 242.94 185.07

267.18 186 295.99 187.29 310.57 188 315.69 189.56 317.15 190

323.32 191.72 324.4 192 331.33 193.03 337.86 194 343.6 194.83

351.49 196 365.43 197.87 365.93 197.93 366.45 198 366.52 198

368.14 198 370.46 198 371.17 198 373.36 198 373.63 198

375.44 198 375.49 198 375.81 198 375.83 198 376.09 198

376.11 198 376.87 198.1 377.77 198.19 378.87 198.39 379.79 198.52

382.81 199.08 387.73 200 387.74 200 387.75 200 387.76 200



0 .03 123.13 .05 155.21 .03


123.13 155.21 10.31 10 12.81 .1 .3





















































CROSS SECTION



INPUT





0 190 6.33 188 8.39 187 10.44 186 12.43 185

14.54 184 18.71 183 30.85 182 66.53 181 75.7 180.65

78.14 180.55 80.64 180.58 95.51 181 122.48 182 126.73 181

126.73 175.67 146.73 175.67 146.73 182.5 177.43 183 207.15 184

231.14 184.76 241.16 185.07 265.4 186 294.21 187.29 308.79 188

313.91 189.56 315.37 190 321.54 191.72 322.62 192 329.55 193.03

336.08 194 341.82 194.83 349.71 196 363.65 197.87 364.15 197.93

364.67 198 364.74 198 366.36 198 368.68 198 369.39 198

371.58 198 371.85 198 373.66 198 373.71 198 374.03 198

374.05 198 374.31 198 374.33 198 375.09 198.1 375.99 198.19

377.09 198.39 378.01 198.52 381.03 199.08 385.95 200 385.96 200

385.97 200 385.98 200



0 .03 122.48 .05 146.73 .03


122.48 146.73 12 12 12 .1 .3























































BRIDGE



INPUT

Description: Animal Hospital Bridge

Distance from Upstream XS = .2

Deck/Roadway Width = 11.67


Weir Coefficient = 2.6

Upstream Deck/Roadway Coordinates

num= 5

Sta Hi Cord Lo Cord Sta Hi Cord Lo Cord Sta Hi Cord Lo Cord

122.48 182 170 123.04 182.44 170 126.73 182.51 181.18

146.73 182.87 181.54 150.59 182.84 170

Upstream Bridge Cross Section Data



0 190 6.33 188 8.39 187 10.44 186 12.43 185

14.54 184 18.71 183 30.85 182 66.53 181 75.7 180.65

78.14 180.55 80.64 180.58 95.51 181 122.48 182 126.73 181

126.73 175.67 146.73 175.67 146.73 182.5 177.43 183 207.15 184

231.14 184.76 241.16 185.07 265.4 186 294.21 187.29 308.79 188

313.91 189.56 315.37 190 321.54 191.72 322.62 192 329.55 193.03

336.08 194 341.82 194.83 349.71 196 363.65 197.87 364.15 197.93

364.67 198 364.74 198 366.36 198 368.68 198 369.39 198

371.58 198 371.85 198 373.66 198 373.71 198 374.03 198

374.05 198 374.31 198 374.33 198 375.09 198.1 375.99 198.19

377.09 198.39 378.01 198.52 381.03 199.08 385.95 200 385.96 200

385.97 200 385.98 200



0 .03 122.48 .05 146.73 .03

Bank Sta: Left Right Coeff Contr. Expan.

122.48 146.73 .1 .3

Downstream Deck/Roadway Coordinates

num= 4

Sta Hi Cord Lo Cord Sta Hi Cord Lo Cord Sta Hi Cord Lo Cord

122.75 182.41 170 126.73 182.52 181.19 146.73 182.88 181.55

150.57 182.85 170

Downstream Bridge Cross Section Data



0 190 4.87 188 7.03 187 11.77 186 13.85 185

15.85 184 22.17 183 30.25 182 73.81 181 94.23 180.22

97.6 180.09 100.08 180 100.52 180 101.17 180.12 109.64 181

126.73 181.55 126.73 175.62 146.73 175.62 146.73 182.3 156.53 182

181.86 183 211.11 184 232.78 185 248.95 186 274.64 187

308.11 188 314.71 190 321.98 192 335.43 194 349.06 196

364.03 198 385.33 200



0 .03 126.73 .05 146.73 .03

Bank Sta: Left Right Coeff Contr. Expan.

126.73 146.73 .1 .3

Upstream Embankment side slope = 0 horiz. to 1.0 vertical

Downstream Embankment side slope = 0 horiz. to 1.0 vertical

Maximum allowable submergence for weir flow = .98

Elevation at which weir flow begins =

Energy head used in spillway design =

Spillway height used in design =

Weir crest shape = Broad Crested

Number of Bridge Coefficient Sets = 1

Low Flow Methods and Data

Energy

Selected Low Flow Methods = Highest Energy Answer

High Flow Method

Energy Only

Additional Bridge Parameters

Add Friction component to Momentum

Do not add Weight component to Momentum

Class B flow critical depth computations use critical depth

inside the bridge at the upstream end

Criteria to check for pressure flow = Upstream energy grade line

CROSS SECTION



INPUT




0 190 4.87 188 7.03 187 11.77 186 13.85 185

15.85 184 22.17 183 30.25 182 73.81 181 94.23 180.22

97.6 180.09 100.08 180 100.52 180 101.17 180.12 109.64 181

126.73 181.55 126.73 175.62 146.73 175.62 146.73 182.3 156.53 182

181.86 183 211.11 184 232.78 185 248.95 186 274.64 187

308.11 188 314.71 190 321.98 192 335.43 194 349.06 196

364.03 198 385.33 200



0 .03 126.73 .05 146.73 .03



126.73 146.73 24 19.82 25.55 .1 .3




















































CROSS SECTION



INPUT

Description:



0 190 3.02 188.9 5.36 188 9.06 186.53 10.36 186

13.58 184.69 15.27 184 17.86 182.95 19.82 182.15 20.18 182

75.97 180.83 85.68 180.64 113.35 180.11 115.06 180.07 115.49 180.06

117.85 180 123.14 179 125.37 178 127.52 177 127.77 175.53

137.82 175.53 147.86 175.53 148.13 177 149.18 178 150.24 179

151.12 180 152.15 181 154.19 182 156 182 159.93 181.94

160.21 182 164.78 182.16 169.69 182.34 177.15 182.61 193.18 183.11

199.66 183.33 207.27 183.58 208.45 183.62 209.57 183.65 221.45 184

222.5 184 234.19 184.47 255.74 185.4 268.63 186 285.73 186.89

308.56 188 313.43 189.51 314.99 190 318.1 190.92 320.7 191.74

321.55 192 331.58 193.23 336.62 193.85 337.85 194 350.4 195.87

351.2 196 352.9 196.19 355.15 196.45 368.84 198 382.51 199.3

386.35 199.66 389.97 200



0 .03 115.06 .05 164.78 .03


115.06 164.78 20.46 20.18 20.03 .1 .3


















































CROSS SECTION



INPUT

Description:



0 190 2.09 189.04 4.51 188 6.71 187.09 9.34 186

12.44 184.71 14.16 184 17.71 182.53 18.99 182 19.03 182

19.08 182 19.15 182 52.98 181.29 80.2 180.72 111.45 180.06

114.43 180 116.08 180 118.1 179 120.11 178 122.13 177

124.14 176 125.26 175.44 135.33 175.44 145.42 175.44 146.93 176

148.02 177 149.02 177 151.55 178 153.98 179 157.69 180

160.94 181 163.61 182 193.27 182.97 209.48 183.44 210.65 183.48

228.13 184 262.86 185.62 271.08 186 274.7 186.19 285.6 186.79

307.24 188 308.2 188 312.78 188.93 318.8 190 320.82 190

321 190.05 321.15 190.09 324.15 190.75 325.69 190.94 327.54 191.43

328.44 191.54 330.46 192 331.26 192.14 331.39 192.19 331.52 192.24

334.27 192.62 334.49 192.72 335.04 193.03 336.78 194 337.35 194.07

337.41 194.09 339.45 194.34 339.76 194.39 341.21 194.55 342.23 194.64

342.62 194.71 343.37 194.77 344.37 194.77 344.85 194.91 345.59 194.93

345.84 195 346.19 195.07 347.11 195.11 347.52 195.18 347.97 195.27

348.48 195.37 349.28 195.42 349.7 195.54 350.04 195.62 350.24 195.67

350.55 195.69 350.6 195.69 350.99 195.66 351.2 195.66 351.94 195.6

352.06 195.59 352.15 195.59 352.22 195.59 353.26 195.5 353.31 195.49

353.36 195.49 353.4 195.49 354.27 195.44 354.3 195.44 355.05 195.42

355.12 195.43 355.21 195.45 355.89 195.47 356.92 195.58 357.02 195.6

358.68 195.87 358.7 195.88 358.97 196 359.34 196 361.37 196.27

362.15 196.48 363.97 196.81 366.21 197.53 366.7 197.65 366.91 197.7

367.67 198 367.69 198 371.66 198.3 373.17 198.41 375.06 198.55

376.71 198.67 378.14 198.78 385.29 199.29 394.51 200 394.6 200

394.72 200 395.21 200



0 .03 111.45 .05 163.61 .03


111.45 163.61 36.48 100.46 36.67 .1 .3


















































CROSS SECTION



INPUT

Description:



0 190 2.09 189.04 4.51 188 6.71 187.09 9.34 186

12.44 184.71 14.16 184 17.71 182.53 18.99 182 19.03 182

19.08 182 19.15 182 52.98 181.29 80.2 180.72 110.88 180.37

115.3 180.27 115.86 180 117.86 179 119.86 178 121.87 177

123.87 176 125.32 175.27 135.33 175.27 145.35 175.27 147.35 176

149.36 177 159.37 177 161.38 178 163.38 179 165.38 180

167.39 181 169.39 182 193.27 182.97 209.48 183.44 210.65 183.48

228.13 184 262.86 185.62 271.08 186 274.7 186.19 285.6 186.79

307.24 188 308.2 188 312.78 188.93 318.8 190 320.82 190

321 190.05 321.15 190.09 324.15 190.75 325.69 190.94 327.54 191.43

328.44 191.54 330.46 192 331.26 192.14 331.39 192.19 331.52 192.24

334.27 192.62 334.49 192.72 335.04 193.03 336.78 194 337.35 194.07

337.41 194.09 339.45 194.34 339.76 194.39 341.21 194.55 342.23 194.64

342.62 194.71 343.37 194.77 344.37 194.77 344.85 194.91 345.59 194.93

345.84 195 346.19 195.07 347.11 195.11 347.52 195.18 347.97 195.27

348.48 195.37 349.28 195.42 349.7 195.54 350.04 195.62 350.24 195.67

350.55 195.69 350.6 195.69 350.99 195.66 351.2 195.66 351.94 195.6

352.06 195.59 352.15 195.59 352.22 195.59 353.26 195.5 353.31 195.49

353.36 195.49 353.4 195.49 354.27 195.44 354.3 195.44 355.05 195.42

355.12 195.43 355.21 195.45 355.89 195.47 356.92 195.58 357.02 195.6

358.68 195.87 358.7 195.88 358.97 196 359.34 196 361.37 196.27

362.15 196.48 363.97 196.81 366.21 197.53 366.7 197.65 366.91 197.7

367.67 198 367.69 198 371.66 198.3 373.17 198.41 375.06 198.55

376.71 198.67 378.14 198.78 385.29 199.29 394.51 200 394.6 200

394.72 200 395.21 200



0 .03 115.3 .05 169.39 .03


115.3 169.39 66.03 100.46 68.96 .1 .3


















































CROSS SECTION



INPUT

Description:



0 190 4.56 189 5.26 188.85 8.28 188 11.69 187.13

16.08 186 16.43 185.94 18.14 185.67 25.64 184.47 26.66 184.3

29.04 184 34.59 183.08 35.09 183.02 37.9 182.65 39.49 182.42

41.95 182 43.4 182 44.75 182 45.8 182 48.88 182

54.3 182 55.49 182 63.64 182 82.82 180.64 86.6 180.14

87.42 180.12 88.04 180.1 89.1 180 91.31 180 91.61 180

94.57 180 98.45 180 103.78 180 109.64 180 112.42 180

115.28 180 115.72 180 117.28 180 119.08 180 119.33 180

120.51 180 121.98 180 132.79 180 134.79 179 136.79 178

138.79 177 140.79 176 142.79 175 150.79 175 160.79 175

162.79 176 164.79 177 192.08 177 194.79 178 196.29 179

198.29 180 202.3 181 206.25 182 212.87 183 215.33 183.5

218.47 184 227.44 184 230.03 184 230.2 184 234.12 184

243.8 184 245.37 184 246.66 184 254.66 184 271.4 184

287.98 184 291.66 184 302.78 184 303.96 184 304.23 184

305.18 184.35 309.54 186 309.71 186.07 314.64 188 318.4 189.51

319.64 190 321.51 190.74 324.68 192 332.69 193.52 335.24 194

340.04 194.42 357.45 196 357.62 196 358.58 196 372.39 197.74

374.47 198 378.35 198.78 384.48 200



0 .03 119.33 .05 215.33 .03


119.33 215.33 47.87 46.97 47.69 .1 .3






















































CROSS SECTION



INPUT

Description:



0 190 3.07 188.68 4.66 188 4.96 187.85 8.55 186

14.51 185.61 18.29 185.47 41.22 184 48.25 184 53.77 184

56.68 184 59.07 184 79.51 184 80.73 184 88.39 184

88.86 184 89.12 184 101.52 184 103.34 184 121 184

130 177.7 144 174.8 164 176 192 180 192.19 180.21

199.35 182 200.01 182.03 211 182.61 240.94 183.49 259.51 184

269.12 184 272.76 184 278.91 184 287.39 184 288.03 184.21

293.4 186 293.55 186.05 294.52 186.37 299.4 188 301.53 188.73

305.35 190 305.62 190 305.85 190 306.74 190 319.49 191.14

324.59 192 331.54 193.71 332.74 194 334.94 194.52 341.97 196

343.36 196.22 345.8 196.61 351.67 197.53 354.63 198 359.24 199.25

361.86 200



0 .03 121 .05 200.01 .03


121 200.01 714.4 707.33 716.09 .1 .3




W.S. Elev (ft) 182.81 Reach Len. (ft)









Length Wtd. (ft) Wetted Per. (ft) 79.85 17.76



Frctn Loss (ft) Cum Volume (acre-ft)

C & E Loss (ft) Cum SA (acres)












Length Wtd. (ft) Wetted Per. (ft) 73.18
















Length Wtd. (ft) Wetted Per. (ft) 66.69





SUMMARY OF MANNING'S N VALUES

River:Laguna Canyon

Reach River Sta. n1 n2 n3

Reach1 1104 .03 .05 .03

Reach1 1055 .03 .05 .03

Reach1 1043_00 .03 .05 .03

Reach1 1036_07 .03 .05 .03

Reach1 1013_30 .03 .05 .03

Reach1 997_47 .03 .05 .03

Reach1 987_57 .03 .05 .03

Reach1 966_78 .03 .05 .03

Reach1 957_87 .03 .05 .03

Reach1 931_112 .03 .05 .03

Reach1 922_122 .03 .05 .03

Reach1 916_129 .03 .05 .03

Reach1 906_139 .03 .05 .03

Reach1 900 Bridge

Reach1 894_151 .03 .05 .03

Reach1 875 .03 .05 .03

Reach1 855 .03 .05 .03

Reach1 819_227 .03 .05 .03

Reach1 754 .03 .05 .03

Reach1 707 .03 .05 .03

SUMMARY OF REACH LENGTHS

River: Laguna Canyon

Reach River Sta. Left Channel Right

Reach1 1104 47.69 48.97 52.11

Reach1 1055 9.67 11.98 14.81

Reach1 1043_00 7.44 7.44 7.44

Reach1 1036_07 24.48 23.02 22.01

Reach1 1013_30 16.6 16.32 16.12

Reach1 997_47 9.82 9.73 10.94

Reach1 987_57 21.71 21.7 21.98

Reach1 966_78 10.41 8.81 7.37

Reach1 957_87 23.27 24.6 26.03

Reach1 931_112 13.79 10.22 6.16

Reach1 922_122 10.27 6.74 2.08

Reach1 916_129 10.31 10 12.81

Reach1 906_139 12 12 12

Reach1 900 Bridge

Reach1 894_151 24 19.82 25.55


Reach1 875 20.46 20.18 20.03

Reach1 855 36.48 100.46 36.67

Reach1 819_227 66.03 100.46 68.96

Reach1 754 47.87 46.97 47.69

Reach1 707 714.4 707.33 716.09

SUMMARY OF CONTRACTION AND EXPANSION COEFFICIENTS

River: Laguna Canyon

Reach River Sta. Contr. Expan.

Reach1 1104 .1 .3

Reach1 1055 .1 .3

Reach1 1043_00 .1 .3

Reach1 1036_07 .1 .3

Reach1 1013_30 .1 .3

Reach1 997_47 .1 .3

Reach1 987_57 .1 .3

Reach1 966_78 .1 .3

Reach1 957_87 .1 .3

Reach1 931_112 .1 .3

Reach1 922_122 .1 .3

Reach1 916_129 .1 .3

Reach1 906_139 .1 .3

Reach1 900 Bridge

Reach1 894_151 .1 .3

Reach1 875 .1 .3

Reach1 855 .1 .3

Reach1 819_227 .1 .3

Reach1 754 .1 .3

Reach1 707 .1 .3


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Documents

APPENDIX D Project Feasibility Report