subject: erosion repair design, sweetwater marsh unit. san ... · conducted a site inspection on 22...

19 September 2016 Mr. MaryAnn Amann Environmental Compliance Coordinator U.S. Fish and Wildlife Service 911 NE 11th Avenue Portland, Oregon 97232 Subject: Erosion Repair Design, Sweetwater Marsh Unit. San Diego Bay National Wildlife Refuge, CA Dear Ms. Amann: Star Resources Corporation (STAR) appreciates the opportunity to provide a Design Plan for the Repair of Eroding Banks to the U.S. Fish & Wildlife Service (FWS), which presents our understanding of the site, project objectives, approach and a budgetary cost estimate to complete erosion control repairs at the Sweetwater Marsh Unit of the San Diego Bay National Wildlife Refuge (NWR) in Chula Vista, California (Site). As requested, we have developed this Plan in conjunction with Geosyntec Consultants, Inc. (Geosyntec) in the evaluation of the erosion issues and the subsequent development of a design, and subsequent implementation of the chosen remedy for erosion control. The portion of the Site where erosion has been observed is located in the western portion of the Connector Marsh along the Metropolitan Transit Authority (MTA) rail lines. Should you have any questions or need additional information, please contact me by email at [email protected] or directly at (805) 431-1418. Best Regards, Star Resources Corporation

Kelly Stater Program Manager Attachment

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621 SW Morrison Street, Suite 600 Portland, Oregon 97205

PH 503.222.9518 FAX 971.271.5884

www.geosyntec.com

Geosyntec Project PNG0721

M e mo r a n d u m

Date: 09 September 2016

To: Kelly Stater – Star Resources Corp.

From: Joey Hickey – Geosyntec Consultants Sean Ragain – Geosyntec Consultants Miguel Parames – Geosyntec Consultants Michael V. Harding

Subject: Erosion Control Design Documents Sweetwater Marsh Time Critical Removal Action

This memorandum and attached design documents have been prepared based on the results of Gesoyntec’s evaluation of potential erosion control alternatives being considered as part of Time Critical Removal Action (TCRA) at the Sweetwater Marsh Unit of the San Diego Bay National Wildlife Refuge (NWR) in Chula Vista, California (Site). This memorandum and design documents were completed in partial fulfillment of the U.S. Fish and Wildlife Service (FWS) statement of work associated with Contract Award F16PX00980. A design document for the implementation of the erosion control measures is attached for your review.

1. BACKGROUND

The San Diego County Department of Health, acting as the Local Enforcement Agency (LEA), conducted a site inspection on 22 September 2015. During the inspection, the LEA observed that a soil cap installed along the western portion of the Connector Marsh was eroding resulting in the release of underlying burn ash to the adjacent marsh. The inspection also noted that since the last inspection (2014), new areas of erosion were observed. Site visits conducted by representatives from the FWS, the LEA, Star Resources Corp. (Star) and Geosyntec confirmed that approximately 325 linear feet (LF) of shoreline requires reinforcement. The LEA has required that FWS implement a corrective action for the portions of the Site in Connector Marsh that were observed to be actively eroding. A second site visit conducted by Geosyntec on August 5, 2016 identified additional areas of erosion and provided additional information to refine a previous memo detailing potential erosion control measures submitted on June 8, 2016. The following sections describe the findings of the second site visit as well recommended Best Management Practices (BMPs) for erosion and sediment control.

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Sweetwater Marsh Erosion Control Design Documents 09 September 2016 Page 2


2. SITE VISIT AUGUST 5, 2016

The second site visit was conducted during a negative (-) low tide in order to better assess the slope conditions typically below the water line. The findings during the site visit include:

· Tidal fluctuations appear to saturate the bank slopes and in some events, extend above the crest of the slopes. The repeated saturation of the bank during tidal fluctuations appears to be the cause of sloughing on steep banks. Similar observations were observed on the opposite bank from the site.

· Existing vegetation appeared to be in satisfactory condition and is recommended to be preserved throughout the site. The existing vegetation appears to be an effective erosion control measure.

· Drainage paths located on flatter portions appear to be contributing to erosion of bank. Based on the results of the second site visit, Geosyntec developed BMPs for select areas which are discussed in the following section.

3. RECOMMENDED BMP TREATMENT CATEGORIES

Based on observations during the second site visit, five required BMP treatments identified by Geosyntec are recommended as presented below:

1. Installation, Inspection and Monitoring: Installation of all BMPs must be conducted in the order specified and supervised by a qualified professional. Recommended routine inspections of all treated areas must also be conducted by a qualified professional for a period of time and at intervals specified by the LEA. All equipment entering the site shall be properly inspected to be free of any foreign plant material as required by the FWS.

2. Tracking Control: Installed during BMP installation to limit off-site discharge of sediment from vehicle wheels.

3. Signage: Signage is recommended to be installed at potential access locations to limit pedestrian and wheeled traffic on remediated area.

4. Preservation of Existing Vegetation: Preserve existing vegetation to limit area of disturbance. Current vegetative cover appears to be in satisfactory condition for erosion control.

5. Coir Logs: Installed along toe of steep banks to contain material from slump areas due to rising tides saturating the soil resulting in sloughing of bank over time.

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Figure 1 illustrates how these various practices are installed in combination to create an effective “Treatment Train.” Detail descriptions of BMPs discussed above are provided in Attachment 1 and select BMP Product Specification Sheets are in Attachment 2.

Figure 1. Schematic Diagram Illustrating Sediment Control BMP Installation.

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4. EROSION AND SEDIMENT CONTROL BMP INSTALLATION LOCATION FIGURES

Figures indicating the proposed locations for installation of the BMPs described in this document are presented in Attachment 3.

5. ENGINEER’S QUANTITY AND COST ESTIMATE

The Engineer’s quantity and cost estimate is presented in Attachment 4.

* * * * *

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ATTACHMENT 1

Detailed BMP Descriptions

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RECOMMENDED BMP TREATMENT CATEGORIES Sweetwater Marsh Erosion Control Design Documents

1

BMP 1. Installation, Inspection, and Monitoring

Installations, application and inspection of BMPs are recommended to be:

• Take place in the order specified (BMP 1-5). • Supervised by a Qualified SWPPP Developer (QSD) and Certified Professional in Erosion and

Sediment Control (CPESC) who is familiar with the installation and maintenance of the specified BMPs.

• In the case of coir log installation, take place at low tide. • Be routinely monitored by a Qualified SWPPP Practitioner (QSP) at an interval established by

the LEA. • Be assessed for their individual structural integrity and their performance as part of a system,

or “treatment train” during inspections. • Be documented by written comment and photos, with damaged or defective BMP removed,

renovated or replaced.

BMP 2. Tracking Control

A shaker plate-type tracking control device shall be placed at the entrance to the construction area prior to any construction taking place on the Site. The device shall be routinely inspected and maintained during active construction to ensure that mud and debris are not tracked off-Site by vehicles or workers. A back-up system comprised of hand equipment (i.e., brooms, brushes, etc.) or a street sweeper shall be in place and maintained during the life of the construction project.

An example of a tracking control shaker plate.

BMP 3: Signage to Limit Access

It is recommended that signage be posted at the northern and southern access points to the Site delineating the remediation area in order to limit pedestrian and wheeled access.

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DETAILED BMP DESCRIPTIONS Sweetwater Marsh Erosion Control Design Documents

2

BMP 4: Preservation of Existing Vegetation

It is suggested that all existing vegetation be protected – e.g., neither cut nor removed - and that any BMPs at the Site be installed with an effort limiting vegetation disturbance.

Example of Existing Vegetation.

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DETAILED BMP DESCRIPTIONS Sweetwater Marsh Erosion Control Design Documents

3

BMP 5: Coir Fiber Logs

Coir fiber logs are recommended for installation at the toe of the west Connector Channel slopes on the flat area exposed at low tide. The coir logs should be constructed of 100% coconut fiber – including the netting – and have the following nominal dimensions:

Diameter Length Density Weight Netting Stake Height

Stake Spacing*

12-, 16-, and 20- inches 10 feet 9 lbs/ ft3 12.4 lbs/ft 2” x 2” 3 feet 2.5 feet

*Stakes should be 2” x 2” x 3’ untreated wood or willow (if approved) installed on each side of coir logs and lashed together across the top of the log with heavy rope or twine

Example of Installation of Coir Fiber Log for Bank Protection.

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ATTACHMENT 2

BMP Product Specification Sheets

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Coir Log Installation

STEP 1: Clear the installation area of any debris, trees, rocks or large obstructions. Logs are

designed to come in contact with the soil, so any stumps or potential obstructions should be

removed.

STEP 2: Dig a small trench in the location where the coir logs need to be placed.

STEP 3: Place the logs in the trench and backfill with soil so that the logs are tightly packed

against the slope. Adjacent logs should be positioned so that the ends fit tightly against each

other. Ends should be joined/secured together with coir twine or other suitable ties.

STEP 4: Stake/anchor the logs into position. Logs should be anchored according to site

requirements or specifications. Typical anchoring can be seen below:

Coir Log Installation Guide

Below you find the typical installation for the coconut coir log. Installation requirements and methods

may vary depending on the specifications of your location.

Stream Dia. of Log Anchor Height Anchor Spacing Flow

Large Stream 20” 4’ minimum Every 2’ Heavy Flow

Large Stream 16” 3’ minimum Every 2.5’ Moderate Flow

Medium Stream 12” 30” minimum Every 3’ Moderate Flow

Medium Stream 12” 30” minimum Every 3.5’ Low Flow

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ATTACHMENT 3

Erosion and Sediment Control BMP Installation Location Figures

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t

Site MapErosion Control Plan

Sweetwater MarshSan Diego, California

Sheet1

San Diego August 2016

100 0 10050 Feet

NotesNotes

Legend"S Tracking Controls

Coir Log

Project Boundary

Project Location

Signage

Vicinity Map

t

Tracking Controls

Connector Marsh

Swee

twate

r Rive

r

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Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP, swisstopo, and the GIS UserCommunity

t

Erosion Control PlanSegment A


Sheet2


20 0 2010 Feet

NotesNotes

LegendCoir Log

Connector Marsh

Preserve ExistingVegetation

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t

Erosion Control PlanSegment B


Sheet3


20 0 2010 Feet

NotesNotes

LegendCoir Log

Connector Marsh


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t

Erosion Control PlanSegment C


Sheet4


20 0 2010 Feet

NotesNotes

LegendCoir Log

Connector Marsh


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t

Erosion Control PlanSegment D


Sheet5


20 0 2010 Feet

NotesNotes

LegendCoir Log

Connector Marsh


Signage

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ATTACHMENT 4

Engineer’s Quantity and Cost Estimate

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ENGINEERS COST ESTIMATE

Activity Unit Amount Unit Cost Extended Cost Assumptions/ Estimate Source

Preparation of project plans ls 1 $10,000 $10,000Preparation of Removal Action Work Plan, Health and Safety Plan and other required plans.

Consultant Oversight day 5 $1,500 $7,500 Assumes 5 days oversight Lodging and meals day 5 $204 $1,020 Federal Per Diem rate.

Field vehicle and equipment day 5 $200 $1,000 Vehicle ($125); misc. tools ($75)

20" x 10' Coconut Coir Logs (677.76 LF/10 = 68 logs 8 1.5 = 102 logs) ea 102 $152.00 $15,50016" x 10' Coconut Coir Logs (677.76 LF/10 = 68 logs 8 1.5 = 102 logs) ea 102 $100.00 $10,20012" x 10' Coconut Coir Logs (677.76 LF/10 = 68 logs 8 1.5 = 102 logs) ea 102 $60.00 $6,100

2" x 2" x 48" Wooden Stakes (recommended 48" on phone) ea 2,712 $1.32 $3,600Coir Twine (677.76*5=3388.8LF, 500 LF per roll) roll 7 $31.00 $200

Rumble Plates ls 1 $1,500 $1,500

Mobilization/Demobilization ls 1 $2,500 $2,500 Materials. Labor and Equipment to the SiteInstallation of Coir Logs and rumble plates day 4 $3,800 $15,200 5 man crew

Lodging and meals day 4 $1,020 $4,080 Federal Per Diem rate.Field vehicle and equipment day 8 $200 $1,600 Vehicle ($125); misc. tools ($75)

Project management and administration ls 1 $7,200 $7,200 Assumes approximately 8% of the estimated project costs without contingency.

Reporting ls 1 $10,000 $10,000 Conservative estimate.Subtotal $97,200

10% Contingency $9,700Additional contractor costs associated with prevailing wage $2,600 Assumes 11% of subcontractor labor costs

Total Estimated Costs $109,500

20" x 10' Coconut Coir Logs Additional 20% ea 1 $152 $15216" x 10' Coconut Coir Logs Additional 20% ea 1 $100 $10012" x 10' Coconut Coir Logs Additional 20% yr 1 $60 $60

Total Estimated Costs (per 10 foot section) $300 Does not include installation fees

MOB/DEMOB to Replace COIR Logs day 1 $1,200 $1,200 First day onlyLabor to replace COIR logs (3 sizes) 10 feet 1 $744 $744 labor

1 $0Total Estimated Costs (per 10 foot section) $1,944

Notes and Assumptions:ls = lump sumsy = square yardea = eachyr = year

EPA - Environmental Protection AgencyCost assumes access to MTS and SDGE areas will be arranged by FWS prior to commencement of field activities.

Operations and Maintenance Visit

Project Design

Field Activities - Consultant

Equipment and Supplies

Additional Coir Logs (per 10' Section for 48-inch Height)

Reporting and Project Management - Consultant

Field Activities - Construction Contractor

STAR RESOURCES CORPORATION AND GEOSYNTEC Page 1 of 1

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