05_-_Geotechnical_Report_Addendum_No.1_04302015.pdf

J:\41011854 USIBWC - South Bay\017 PROJECT DELIVERABLES\Geotechnical Final Report\2015-04-30 SBIWTP Addendum 1 GeoRept (URS).doc\1-May-15\SDG

URS Group, Inc.

4225 Executive Square, Suite 1600 La Jolla, CA 92037 Tel: 858.812.9292 Fax: 858.812.9293

April 30, 2015

Ms. Lisa Ramirez U.S. International Boundary and Water Commission (USIBWC) 4171 North Mesa, Suite C100 El Paso, Texas 79902-1441

Subject: Addendum No. 1 Geotechnical Investigation Report South Bay International Wastewater Treatment Plant Improvements San Ysidro, California URS Project No. 41011854.01 USIBWC Task Order – IBM14T0013

Dear Ms. Ramirez:

URS Group, Inc. (URS) has prepared this addendum to provide an updated site plan and revise the dimensions of the proposed project features.

URS completed the geotechnical investigation for the project and prepared a report titled “Geotechnical Investigation, South Bay International Wastewater Treatment Plant Improvements, San Ysidro, California,” and dated February 13, 2015.

This addendum presents an updated Site Plan (Figure 2) based on the 90 percent project design submittal. Further, we understand the capacity of the Equalization (EQ) Tanks is 3.75 million gallons. A capacity of 3.5 million gallons was stated in Section 1.1 of our report dated February 13, 2015.

CLOSURE

This letter should be bound with our February 13, 2015 report on all future submittals.

13'

13'

26'

TP-10

TP-9

B-3

B-4

PROPOSED

SSTs

SST EFFLUENT

CHANNEL

PROPERTY LINE

DIRT ROADWAY

RELOCATED

AC ROAD

RELOCATED DIRT

ROADWAY

RELOCATED DIRT

ACCESS ROAD

SLOPE,

2:1 MAX

S S

T N

O . 1

S S

T N

O . 1

S S

T N

O . 1

AC SPILLWAY

RIP RAP

AR-25

29'

31'

51'

55'

E Q

U A

LI

ZA

TI

O

N

TA

N K

N O

. 2

E Q

U

IL

IZ

A

TI

O

N

TA

N K

N O

. 1

HSA-14

HSA-16

HSA-17

B-1

HSA-20

B-2

PROPOSED

EQ BASIN

AC

ACCESS

ROAD

WET WELL

EQ EFFLUENT PIPE

AC

ACCESS

ROAD

AR-10

EQ INFLUENT PIPE

LEGEND