international boundary and water commissionreaches of its tributaries arroyo cocodrilo and arroyo...

INTERNATIONAL BOUNDARY AND WATER COMMISSION

“REHABILITATION OF THE ARROYO INTERNACIONALTUNNEL IN NOGALES SONORA”

Table of Contents1. Background2. Current Channel Conditions3. Actions to Address the Issue4. Diagnostic Assessment of the Encasement5. Follow-Up Actions

December 2016

1. Background

• The Arroyo Internacional tunnelbegins in Nogales, Sonora,crosses the internationalboundary under the DeConcini-Nogales I Port of Entry and flowsinto the Nogales Wash in theUnited States.

• It has a total length of 2,313 m,of which 944 m are in Mexicoand 1,369 m are in the U.S.(Grand Tunnel).

• In May 2014, IBWC coordinated a binational inspection during which it wasdiscovered that for a section of approx. 180 m upstream of the internationalboundary the floor of the tunnel had disappeared; some segments of walls had lostsupport because of the effects of scour; there is accumulation of sediment anddebris.

• A process to address the issue through the IBWC framework is initiated.

2. Current Channel Conditions

3. Actions to address the issue are undertaken through the IBWC framework:

• 2014. A series of joint inspection visits to the channel are made.

• October 31, 2014 MXIBWC sends letter to Mexicanagencies asking for participation.

• November 13, 2014. CONAGUA’s Technical ConsultingDepartment, OCNO [Northwest River Basin Organization],and MXIBWC inspect the tunnel in Mexico.

• September 30, 2015. MXIBWC meets with the Mayor ofNogales, Sonora to discuss the matter.

• October 30, 2015 Proposal to prepare a Joint TechnicalReport and an IBWC Minute.

• December 2015. The need to perform a diagnosticassessment of the channel anomalies is determined, withthe goal of identifying the measures required tostructurally and functionally rehabilitate the tunnel.

• April 2016. CONAGUA’s Technical Consulting Departmentand MXIBWC carry out a field visit to draft the Terms ofReference for the Diagnostic Assessment.

• CONAGUA provides funding to MXIBWC for them to bedeveloped.

4. “Diagnostic Assessment of the Arroyo Internacional Tunnelin Nogales, Sonora”

TIMELINE:

• July 28, 2016: Clarifications meeting and worksite visit with interested companies.

• August 11, 2016: Submission and opening of thecompanies’ technical and financial proposals.

• August 19, 2016: MXIBWC signs contract withthe Construction Group CARAMECHI to carry outthe “Diagnostic Assessment of the ArroyoInternacional Tunnel in Nogales, Sonora”.

• August 30, 2016: Project kick-off meeting withparticipation by MXIBWC, CONAGUA, MunicipalInstitute for Research and Planning (IMIPNogales), OOMAPAS, and the Mayor of Nogales,Sonora.


TIMELINE:

• November 10, 2016: Second progress reviewmeeting for the “Diagnostic Assessment of theArroyo Internacional Tunnel” Study.

• The purpose of this meeting was to present theprogress in obtaining results from theGeotechnical-Structural Assessment of theArroyo Internacional Tunnel.

• The final report will be submitted by thecompany at the beginning of January 2017.


Project Objectives:

Obtain the geometry of the Arroyo Internacional and the linedreaches of its tributaries Arroyo Cocodrilo and Arroyo S/N (Unnamed)in the study area, including the reach located in the U.S. from theboundary line to the confluence with the Nogales Wash.

Perform diagnostics on the structural stability of the “ArroyoInternacional” tunnel in the last 200 m before the border crossing.

Prepare preliminary plans with a technical-financial proposal forstructural and functional rehabilitation of the “Arroyo Internacional”tunnel in the last 200 m before the border crossing.


STUDY AREA:


THE PROJECT INCLUDES: Complete In progressScheduled for

Dec. 2016

• Measurements of the concrete thickness of the walls, ceiling and invert slabs.

• Sampling to determine the extent of the steel rebar deterioration

4. Conceptualization of the Geotechnical-Structural Model:• Preparation of an interactive geotechnical-

structural model of the various components of the tunnel (walls, slabs, foundation soil and surrounding fills).

5. Analysis of the geotechnical-structural stability:• Technical opinion of the tunnel’s stability.• Service limit tolerances.6. Preliminary plans for the proposed solution. 7. Study Final Report.

1. Collection and Analysis of Existing Data:• Geometry of the Arroyo Internacional

including the reach in the U.S. up to the confluence with the Nogales Wash.

• Regional and local geology.• Structural plans and geotechnical data for the

tunnel.2. Topographic survey: • Longitudinal profiles and cross sections of the

Arroyo Internacional and the lined reached of its tributaries Arroyo Cocodrilo and Arroyo Sin Nombre (Unnamed).

• Hydraulic-Hydrology Models/Studies3. Geotechnical-Structural Assessment of the Tunnel:• Exploration and sampling of subsoil

materials.• Inventory of deficiencies in the encasement

(tunnel conditions).


Topographic survey:


Topographic Survey

Arroyo Internacional(200 before the

international boundary)


Geotechnical-Structural Assessment



Arroyo Internacional(200 before the

international boundary)

• CONAGUA is developing the Hydrologic and HydraulicStudies/Models of the Arroyo Internacional and its tributariesbased on the information gathered by the Project Consultant,which will be finalized by the beginning of December 2016.

• The Consultant will prepare an Executive Summary of the issuesdetected as well as preliminary plans containing a technical-financial proposal for structural and functional rehabilitation ofthe tunnel.

• The Diagnostic Assessment of the Arroyo Internacional shouldbe completed before the end of 2016.

• Presentation of the Project results at the Nogales BinationalTechnical Committee (BTC) meetings in early 2017.

5. Action Items:

international boundary and water commissionreaches of its tributaries arroyo cocodrilo and arroyo...

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