INTERNATIONAL BOUNDARY AND WATER COMMISSION UNITED STATES AND MEXICO

AERIAL VIEW OF ANZALDUAS DIVERSION DAM IN THE LOWER RIO GRANDE

2005

ANNUAL REPORT

INTERNATIONAL BOUNDARY AND WATER COMMISSION UNITED STATES AND MEXICO

“The jurisdiction of the Commission shall extend to the limitrophe parts of the Rio Grande (Rio Bravo) and the Colorado River, to the land boundary between the two countries, and to works located upon their common boundary, each Section of the Commission retaining jurisdiction over that part of the works located within the limits of its own country.”

Article 2, 1944 Water Treaty M E S S A G E F R O M T H E C O M M I S S I O N E R S

During 2005, the International Boundary and Water Commission, United States and Mexico (IBWC) carried out various activities related to boundary demarcation, maintenance of the channels of the interna- tional rivers, control and use of the international waters, and monitoring of the quantity and quality of these waters. These activities were under- taken in conformance with the terms of the boundary and water trea- ties agreed to by the Governments of the United States and Mexico. Ap- plication of these treaties is the responsibility of the IBWC.

During the year, U.S. President George W. Bush designated long- time Commission employee Carlos Marin as Acting Commissioner fol- lowing the resignation of Arturo Q. Duran. The Mexican Section contin- ued to operate under the leadership of longtime Commissioner Arturo Herrera Solis.

The major Commission accomplishment for the year was the resolution of Mexico's deficit in Rio Grande water deliveries to the United States. The breakthrough arrangement, based on the hard work and technical expertise of the Commission, was announced in March by U.S. Secretary of State Condoleezza Rice and her Mexican counterpart, Foreign Secretary Ernesto Derbez. The commitments announced in March were fulfilled and the Commission declared on September 30 that the deficit had been eliminated.

These and other activities are described in this report, which has been prepared in conformance with and in fulfillment of Article 24, paragraph (g), of the 1944 Water Treaty.

______Carlos Marin J. Arturo Herrera Solis Acting United States Commissioner Mexican Commissioner TABLE OF CONTENTS

I. Boundary Demarcation •Lining of the All-American Canal….. 12 •Environmental Preservation of the •Maintenance of Boundary Delta………………………………………………. 12 Demarcation Features………………….... 1 •Water Supply for the City of Tijuana, B.C. ………………………….……… 13 II. Rio Grande •Silt…………………………………………………. 13 •Resolution of the Rio Grande •Lower Colorado River Boundary Water Deficit…………………………………… 2 and Capacity Preservation Project.. 13 •Convention of 1906………………………… 2 •Aquatic Weeds………………………………. 14 •Flood Control - Upper Rio Grande, Lower Rio Grande…………………………… 3 •Operation and Maintenance of IV. Sanitation and Water Amistad Dam…………………………………… 4 Quality •Operation and Maintenance of •Sanitation at San Diego, CA– Falcon Dam……………………………………… 5 Tijuana, B.C. …………………………………. 15 •Power Generation at Amistad and •Sanitation at Calexico, CA – Falcon Dams…………………………………… 5 Mexicali, B.C.…………………………………. 16 •Maintenance of Anzalduas and •Sanitation at Nogales, AZ- Retamal Dams………………………………… 6 Nogales, Son.…………………………………. 16 •Water Conservation Projects in the •Sanitation at Naco, AZ-Naco, Son.. 17 Mexican Irrigation Districts……………. 7 •Sanitation at El Paso, TX - •Environmental Preservation of the Ciudad Juarez, Chih.……………………… 18 Rio Grande……………………………………… 7 •Sanitation at Nuevo Laredo, •Presidio, TX-Ojinaga, Chih.…………… 7 Tamps.…………………………………………… 18 •Control of Invasive Aquatic Plants… 8 ●Water Quality Monitoring……………… 18 •Operation and Maintenance of El Morillo Drain………………………………… 8 •Brownsville, TX- Matamoros, Tamps. Weir...... 9 V. Other Projects •Water Gaging and Weather •Desalinization Study for the San Observation Network………………………. 9 Diego, CA-Tijuana, B.C. Region……. 21 •Binational Rio Grande Summit………. 9 •Transboundary Aquifers………………… 21 •International Bridges………………………22 III. Colorado River •Tecate Port of Entry………………………. 22 •Projects on the Rio Grande •Water Deliveries, Operation and Floodplain………………………………………. 22 Maintenance of Morelos Dam…………. 11 •Tijuana River Flood Control Project. 22 •Operation and Maintenance of the •Nogales Flood Control Project………. 23 Wellton-Mohawk Drain…………………… 11 •Project Map...... 24 •Salinity……………………………………………. 11

2005 Annual Report

I.- BOUNDARY DEMARCATION

Maintenance of Boundary Consequently, during 2005, the Commission inspected and/or Demarcation Features performed maintenance on the boundary markers installed at 16 The Commission is re- international bridges and five land sponsible for demarcating the ports of entry. border between the United States and Mexico. This includes installing and maintaining boundary mon- The U.S. Section undertook uments and markers on the land rehabilitation of several boundary boundary between the two monuments to the west of countries and placing appropriate Nogales, AZ-Nogales, Son. Like- plaques and elements demarcating wise, inspection visits were made the boundary on international to the international monuments in bridges and at the land ports of the border zone to the west of the entry. Colorado River and maintenance was performed as necessary.

Demarcation of the international boundary Monument No. 85A on the at the the Eagle Pass, TX-Piedras Negras, international boundary. Coah. International Bridge. 2005 Annual Report

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Resolution of the Rio both governments through the exchange of diplomatic notes on Grande Water Deficit March 10, 2005.

The IBWC in 2005 marked At the end of September, the resolution of Mexico's long- Mexico completed the water standing deficit in Rio Grande water allotments to the United States in deliveries to the United States keeping with the aforementioned under the 1944 Water Treaty. The understandings. Accordingly, the treaty provides for the distribution Commission declared that the of the waters of the Rio Grande deficit had been eliminated in its between the two countries from entirety and the 1992-1997 and Fort Quitman, Texas to the Gulf of 1997-2002 cycles closed. The two Mexico. In accordance with that IBWC Commissioners formally treaty, Mexico delivers water to the acknowledged the above through United States from six of its Rio the exchange of letters. Grande tributaries in cycles of five years; water from these tributaries is allotted two-thirds to Mexico and Convention of 1906 one-third to the United States. In accordance with the Convention of 1906, the United Starting with the five-year States delivered Rio Grande water cycle that ended in 1997, Mexico to Mexico at Ciudad Juarez, had experienced a deficit in water Chihuahua — water that was re- deliveries to the United States. leased from Elephant Butte and Although some progress had been Caballo Dams in New Mexico. made in prior years to address the During 2005, Mexico received a full deficit, the issue was not resolved treaty allotment of 60,000 acre- until 2005. feet (74 mcm), diverting its water through the Acequia Madre Canal for irrigation in the Juarez Valley. At the beginning of the year, binational negotiations were held in Washington, DC and El The Commission, in coordi- Paso, TX, with the goal of reducing nation with the U.S. Bureau of or eliminating the deficit. As a Reclamation, which operates the result, the IBWC Commissioners two dams, Mexico’s National Water formulated and presented to their Commission, Elephant Butte respective governments recom- Irrigation District, and El Paso mendations on this subject, County Water Improvement agreeing that the volume of the District No. 1, held monthly deficit on October 1, 2004 was meetings to exchange information 716,670 acre-feet (af) or 884 regarding changing runoff and million cubic meters (mcm) and storage conditions in order to identifying water sources for maximize the efficiency of covering this volume. These deliveries by coordinating understandings were endorsed by among users. 2005 Annual Report

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The Commission coordi- nated the schedule for water deliveries to Mexico in 2005, operated the diversion dams in El Paso, TX-Ciudad Juarez, Chih. (American and International Dams), and measured and monitored the volumes delivered.

In February, IBWC officials joined dignitaries from other water agencies from Southern New Commission meeting to develop the Mexico and the area of El Paso, Rio Grande flood control exercise. TX-Ciudad Juarez, Chih. to mark the centennial of the U.S. Bureau of Reclamation's Rio Grande river flowed out of the low-flow Project. The Rio Grande Project channel and onto the floodplain was originally authorized to settle near International Dam. The staff conflicting interests over the monitored the situation closely and limited supply of water within the opened the gates of International Rio Grande Basin of southern Dam in order to lower the water Colorado, New Mexico, and far level. Rains also caused flooding of west Texas. As part of the project, farmland along the Rio Grande Elephant Butte and Caballo Dams downstream of Ft. Quitman, TX. were constructed to supply water Silt from arroyos that flow into the to the region's users, including river is an ongoing problem that Mexico. The project also includes contributes to reduced conveyance flood control and hydroelectric capacity and flooding. power components. Flood Control - The IBWC coordinates Lower Rio Grande closely with Reclamation to ensure that release of waters from Rio In the Lower Rio Grande, Grande Project dams fulfills the Hurricane Emily made landfall on requirements of the Convention of July 20 at a point 80 miles (129 1906. km) south of Brownsville, TX- Matamoros, Tamps., damaging villages in Mexico and generating Flood Control - high flows in the Rio Grande. Upper Rio Grande

The IBWC operates the In August, the Rio Grande Lower Rio Grande Flood Control at El Paso, TX-Ciudad Juarez, Chih. Project, which includes a system of experienced extremely high flow due to locally heavy rainfall. The 2005 Annual Report

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levees and floodways covering 180 both countries to exchange river miles (290 km) from Peñitas, information and strengthen TX-Diaz Ordaz, Tamps. to the Gulf preventive measures to address of Mexico. Emergency personnel flood emergencies in the Rio worked around the clock at Grande. Anzalduas and Retamal Dams, the Commission’s two diversion dams in the project, for several days Operation and immediately following the Maintenance of hurricane. Amistad Dam To limit downstream flows in the Rio Grande at Brownsville, Amistad Dam, located on the TX-Matamoros, Tamps., Mexico Rio Grande near Del Rio, Texas- diverted Emily-related flow at Ciudad Acuña, Coahuila, is operated Retamal Dam into its interior jointly by the two Sections of the floodway. IBWC. The dam provides water storage, flood control, and As a result of the storm, Rio hydroelectric power for both Grande flow at Roma, TX-Ciudad countries. At the end of 2005, Miguel Aleman, Tamps. peaked at joint storage was 2.77 million more than 25,000 cubic feet per acre-feet (3418 mcm) or 88% of second (cfs) (700 cubic meters capacity, similar to end-of-year per second [cms]) and flow at Rio storage in 2004. Grande City, TX-Camargo, Tamps. exceeded 20,000 cfs (560 cms). Still, flow remained within the river’s conveyance capacity. The two Sections coordinated with agencies in both countries to disseminate information and monitor flows, including inflows from Rio Grande tributaries.

As it does every year prior to hurricane season, the Com- mission in June conducted its flood control exercise at Anzalduas and Retamal Dams as well as at the Commission's two international Maintenance of a gate at Amistad reservoirs farther upstream — International Dam at Del Rio-Cd. Acuña. Falcon and Amistad Dams — with the participation of the U.S. The Commission jointly National Weather Service and operated Amistad Dam, releasing Mexico’s National Water Com- water to users in both countries for mission. Additionally, the IBWC water supply to border cities, coordinated with authorities in 2005 Annual Report irrigation, and generation of

4 II .- RIO GRANDE electricity, among other uses. The undertook the silt survey for Falcon Commission also carried out Dam. The Commission will use the required preventive maintenance information gathered in this survey and repair of the equipment, to calculate the new storage components, facilities, instru- capacity of the reservoir. ments, and structure of the dam itself. Power Generation at Amistad and The United States Section concluded the field work for the Falcon Dams Amistad Dam silt survey; this information will be reviewed by the Both countries operate Mexican Section in order to update hydroelectric power plants at calculations for the dam's storage Amistad and Falcon Dams, which capacity. generate electricity equally for both countries.

Operation and Discussions regarding the Maintenance of sharing of power generation Falcon Dam between the two countries during hours of peak demand resumed The IBWC's other large during the calendar year. The storage reservoir on the Rio electric cooperatives in the United Grande is Falcon Dam, located States had asked the IBWC to upstream from Roma, TX – Ciudad review the practice whereby Mexico Miguel Aleman, Tamps. Like generated power during the evening Amistad Dam, Falcon provides hours while the United States water storage, flood control, and generated electricity during the hydroelectric power generation for morning hours. Discussions both countries. At the end of 2005, indicated that evening generation joint storage was 1.62 million acre- was much more valuable to U.S. feet (2001 mcm) or 61% of power companies as compared to capacity. power generated between the hours of midnight and noon.

During 2005, the normal program of monitoring and Internal discussions of the maintenance of the structural and IBWC led to a subsequent meeting mechanical elements of the dam in November with participation of continued. Additionally, the IBWC the State of Texas, the U.S. power conducted operational activities to cooperatives, Mexico's National release volumes of water as Water Commission, and the Federal requested by each country. Electricity Commission of Mexico. As a result of the favorable dis- cussions, the parties agreed to In accordance with IBWC

agreements, the Mexican Section 2005 Annual Report

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develop draft rules to be downstream from Anzalduas, was implemented on a trial basis during built for flood control purposes. It calendar year 2006 to alternate enables Mexico to divert to its power generation during hours of interior floodway its share of Rio peak demand between the two Grande floodwaters and limits flood countries. flows into the area of Brownsville, TX-Matamoros, Tamps.

Maintenance of At Anzalduas Dam, the Anzalduas and stoplogs were sandblasted and Retamal Dams painted, and maintenance of gates #1 and #6 of the dam was

completed, thereby complying with Both Sections of the IBWC international agreements which carried out preventive main- call for maintenance to be tenance on the Anzalduas and performed on two of the six gates Retamal International Diversion each year. Dams on the Rio Grande.

Anzalduas Dam, located near McAllen, TX-Reynosa, Tamps., At Retamal Dam, brush and allows for the diversion of the U.S. weeds were cleared from the areas share of Rio Grande floodwaters to adjacent to the dam and the the interior floodway and the access road, and the handrails, diversion of irrigation water into arms, and counterweights on the Mexico’s canal system. Retamal center floodgate were cleaned and Dam, located 38 miles (61 km) painted.

Gate #1 at Anzalduas Dam was sandblasted as part of preventive maintenance. 2005 Annual Report

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Water Conservation Environmental Projects in the Mexican Preservation of the Irrigation Districts Rio Grande

The Commission reviewed During 2005, the IBWC the 2003-2004 Report of Mexico’s supported several environmental National Water Commission on the agencies and groups in the United progress of the modernization and States and Mexico in the improved technology projects in development of pilot projects for the irrigation districts in the controlling salt cedar (tamarisk) Conchos River Basin, within the along the Rio Grande in the area of context of Minute 309, and Big Bend, TX-Maderas del Carmen, concluded that the agreements of Coah., making it possible for crews the Minute had been fully met. working on the control projects to Minute 309, a 2003 Commission carry out their activities on both agreement, provides for IBWC sides of the international review of volumes of water boundary. Control of this species is conserved through the moderni- a high priority given the elevated zation projects and conveyance of amounts of water it consumes. conserved waters to the Rio Grande. The Commission also lent

support to the coordination of the During the period between Dia del Rio activities in Laredo, TX- January and March 2005, the Nuevo Laredo, Tamps. waters saved from these projects were transferred to the Rio Grande, with a total of 39,822 Presidio, TX— acre-feet (49.12 mcm) reaching Ojinaga, Chih. the Rio Grande. From this volume of water, each country was allotted In 2005, U.S. Section its corresponding proportion in personnel started removal of the accordance with the 1944 Water concrete weir located in the Rio Treaty and Minute 309. Grande channel at the Below gaging station site, 1000 feet (305 meters) east from Alamito Creek In December 2005, the and downstream from Presidio, TX- Commission conducted a joint field Ojinaga, Chih. The weir had been visit to the Conchos River irrigation partially removed in the early districts to observe the progress on 1990s. The weir had created an works and investments corre- obstruction to flows, thus allowing sponding to the 2004-2005 sediment to be deposited upstream agricultural season. and downstream of the weir, a problem that worsened with each high flow. A sandbar had been

created where vegetation, consisting mainly of salt cedar, had established itself. The sandbar had 2005 Annual Report

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become a hazard, affecting the replacement of concrete panels in gaging station and operation of the the drain, and cleaning of the cableway across the river used for siphons. Emergency works to clean water measurement purposes. up the drain at critical points were This gaging station measures Rio also performed. In addition, Grande flows directly downstream binational meetings were held with from Presidio-Ojinaga, which the participation of the two IBWC account for inputs from the Sections and Mexico’s National Conchos River and Alamito Creek. Water Commission to follow up on the electrical repairs at the pumping station. Control of Invasive Aquatic Plants The Commission also initiated discussions to develop a Inspection visits were made project for renovation of El Morillo to the Rio Grande channel, where Drain in order to reduce the a notable increase was observed in amount of maintenance required to invasive species such as hydrilla keep the drain in good operating (Hydrilla verticillata) and water order. During the year, the United hyacinth, (Eichhornia crassipes) in States Environmental Protection the reach of the Rio Grande Agency transferred to the U.S. between Falcon Dam and Rio Section appropriated funds in the Grande City, TX-Ciudad Camargo, amount of $625,000 for design Tamps. covering approximately and construction. The project will 37.3 river miles (60 km). Studies likely include encasing the drain were performed and courses of with reinforced concrete in critical action developed to control these areas to reduce the accumulation invasive species. In addition, of sediment and other debris. binational meetings were held on Construction is expected to begin the topic. in early 2007.

Operation and Maintenance of El Morillo Drain

El Morillo Drain, located in the State of Tamaulipas, Mexico, is a binational project that conveys saline irrigation return flows to the Gulf of Mexico, thereby reducing the salinity of the Rio Grande. Consistent with the agreements in Minutes 223 and 303 of the International Boundary and Water Commission, maintenance works were carried out during the year,

2005 Annual Report including the removal of sediment, Morillo Drain Pumping Plant 8

II .- RIO GRANDE

Brownsville, TX- gaging stations on the Rio Grande, Colorado River, and tributaries. Matamoros, Tamps. Each Section is responsible for the Weir operation and maintenance of

gaging stations on the tributaries in its respective country. Most The IBWC convened stations use satellite telemetry to stakeholders from both countries provide near real-time water level to discuss the proposed data, including six stations Brownsville-Matamoros Weir installed on Mexican tributaries in project, which entails construction 2005. The Commission collects of a weir (a kind of dam) across hydrometric and weather data, the Rio Grande to enhance the which is processed and used in bi- municipal water supply for both national water accounting cities. During the meetings, computations, dam operations, concerns expressed by Mexico and real-time flood operations. regarding the potential effects of The data is compiled and published weir operation on groundwater in the annual Water Bulletins. table elevations were addressed.

Consultants for the Brownsville Public Utilities Board (PUB) made a Binational presentation based on a study they performed of groundwater table Rio Grande Summit elevations in Matamoros resulting from the operation of the weir Some 200 stakeholders project. The study concluded that from throughout the Rio Grande buildings in Matamoros would not Basin gathered in McAllen, TX- be affected by the increase in Reynosa, Tamps. on November 17- groundwater table elevation. 18, 2005 for the Binational Rio However, Mexico’s National Water Grande Summit sponsored by the Commission made a presentation IBWC. The objective of the indicating that certain low areas in Summit was to convene experts Matamoros would be negatively impacted. Mexico concluded that and water users from the basin to develop recommendations for the site proposed by the PUB consideration by the Governments would not be acceptable unless certain mitigation measures were of the United States and Mexico related to sustainable management adopted. Other sites were of the basin. Participants included considered but no decision was reached. representatives from local, state, and federal government, academics, environmental organi- Water Gaging and zations, municipal water utilities, Weather Observation farmers, and irrigation districts from both countries. Network

The Commission operated and maintained more than 60 2005 Annual Report

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The Binational Rio Grande Summit recommendations, which resulted from two days of presen- tations and discussion, focused on four broad conference themes:

• Legal and Institutional Aspects

• Binational Basin Management

• Environment and Water Quality

• Finance.

The recommendations in- cluded such things as conducting binational information sharing, supporting and funding water in- IBWC Commissioners Arturo Herrera (l) and Carlos Marin frastructure projects, and devel- at the Binational Rio Grande Summit. oping incentives to promote water conservation.

Closing session of the Binational Rio Grande Summit at Mc Allen, TX– Reynosa, Tamps. 2005 Annual Report

10 III .- COLORADO RIVER

Water Deliveries, (34 km) from the international boundary and replacement of Operation and concrete panels on the side slopes. Maintenance of Morelos Dam Salinity

In accordance with the During 2005, cooperative stipulations of the 1944 Water measures continued to improve Treaty, the United States delivered the quality of Colorado River water to Mexico a full allotment of delivered to Mexico at the Colorado River water for 2005. To Northerly International Boundary effect these deliveries, the Mexican and Southerly International Boun- Section of the Commission dary. In accordance with Minute operated the Morelos Diversion 242, the salinity of waters Dam near Yuma, Arizona - Los delivered to Mexico must be similar Algodones, Baja California, assur- to that delivered to U.S. users at ing diversion of Mexico's share of Imperial Dam; to achieve this, the water to Colorado River Irrigation Minute establishes a salinity differ- District 014. Additionally, the ential, essentially a cap on the Mexican Section continued its difference between the salinity of program of sampling for waters available to each country. suspended sediments that arrive at Morelos Dam. In accordance with the maintenance program, the To resolve discrepancies Mexican Section also carried out between U.S. and Mexican improvements such as the laboratory results for salinity levels installation of cathodic protection in water samples, meetings were on the gates of the dam and held throughout 2005 to review replacement of the emergency sampling techniques, testing generator. methodology, and the results of tests performed by both countries. The purpose of these efforts was to Operation and standardize the results from the Maintenance of the salinity analyses performed by the Wellton-Mohawk Drain two countries.

From October 2004 to The Wellton-Mohawk Drain January 2005, the system installed bypasses saline irrigation return at the Southerly International flows from the United States to Boundary (SIB) underwent testing improve the quality of Colorado and calibration to improve the River water delivered to Mexico. quality of the water delivered to Maintenance performed under Mexico at this site. Due to Minute 284 was limited in 2005 personnel and equipment issues, due to budget constraints. It this system will not be fully included clearing and vegetation operational until late 2007. removal for a length of 21 miles 2005 Annual Report

11 III .- COLORADO RIVER

This system includes a The Mexican Section of the diversion channel to divert Yuma IBWC has expressed its disagree- Valley agricultural drainage waters ment with the plans that the into the Wellton-Mohawk Bypass United States intends to carry out Drain and a variable speed pump for this project because of installed at the Main Drain potential negative impacts in Pumping Plant to reduce the large Mexico. The Commission arranged fluctuations of flow in water meetings with technical advisers delivered to Mexico during the four from both countries in February, months of the year specified by April, June, and July 2005, in Mexico (October, November, which Mexican officials presented December, and January), thereby information about potential effects decreasing the salinity spikes. An in Mexico should the All-American improvement in the salinity of the Canal be lined. Information was water delivered at the SIB has also exchanged on possible been observed during the critical cooperative options to address the months mentioned. potential impacts of the project in Mexican territory. At year's end, discussion of these options was For 2005, the salinity ongoing. differential between Imperial Dam and Morelos Dam was 118 parts per million (ppm) according to the Mexican standards and 95 ppm Environmental according to United States Preservation of the standards, meeting the levels Delta stipulated in Minute 242. In 2005, under the Lining of the All- framework of IBWC Minute 306, “Conceptual Framework for United American Canal States-Mexico Studies for Future Recommendations Concerning the The All-American Canal, Riparian and Estuarine Ecology of located near the international the Limitrophe Section of the boundary in the United States, Colorado River and its associated conveys Colorado River water for Delta,” the Commission compiled a agricultural irrigation in the Imperial Colorado River Delta database that and Coachella Valleys of California. was posted on the websites of the Given the increasing demand for two IBWC Sections. water in the region, water managers plan to line a reach of the Additionally, nongovern- canal to prevent water loss through mental organizations (NGOs) that seepage so that this conserved are members of the Advisory water can be used in urban areas Group established by the along the California coast. The Commission pursuant to Minute preferred alternative for the lining is 306 prepared a report, “Conser- to construct a 23-mile (37-km) vation Priorities in the Colorado canal parallel to the existing one.

2005 Annual Report

12 III .- COLORADO RIVER

River Delta,” which they shared Silt with the Commission so that the conservation and environmental During 2005, weekly sedi- protection projects for the ment sampling was conducted at Colorado River Delta could be the Northerly International considered by authorities in both Boundary in the Colorado River countries. The Commission sched- immediately upstream from uled Advisory Group meetings for Morelos Dam. The U.S Bureau of the early part of 2006 to review Reclamation continued desilting the NGO document. works in the area of Imperial Dam, 18 miles (29 km) upstream of Water Supply for the Yuma, Arizona, removing approxi- mately 1.0 million cubic yards City of Tijuana, B.C. (.756 million cubic meters) of silt. This activity is scheduled to be Within the framework of completed in June 2006. IBWC Minute 310, "Emergency Delivery of Colorado River Water Because no flooding oc- for use in Tijuana, Baja California," curred in 2005 on the Gila and Bill it was agreed to provide Tijuana Williams Rivers (U.S. tributaries to with water through the Southern the Colorado River), sediment California Aqueduct System for conditions were normal at the five years starting in 2003; this Northerly International Boundary. water is allotted to Mexico in The settling basin constructed in Article 10(a) of the 1944 Water 2001 in the Colorado River Treaty. In 2005, 163 acre-feet immediately upstream of Morelos (201,470 cubic meters) of water Dam has worked according to was delivered. Under the terms of design, preventing large volumes Minute 310, Mexico compensates of silt from entering Mexico's canal affected entities in the United system in the Mexicali Valley. States for all costs associated with these deliveries. Lower Colorado River Boundary and Capacity Preservation Project

The objective of the Lower Colorado River Boundary and Capacity Preservation Project is to study and implement a channel configuration that ensures sufficient capacity to convey floodwaters through the inter- national reach of the Colorado River, preserves the international Personnel operating the Emergency Con- boundary line, and considers nection to supply water to Tijuana, B.C.

environmental aspects. 2005 Annual Report

13 III .- COLORADO RIVER

During 2005, the United Giant salvinia is a floating States Section initiated a process fern that can clog water intakes for in coordination with the U.S. irrigation, impede recreational Bureau of Reclamation and its activities, such as boating and consultant, Brown & Caldwell, to fishing, and degrade water quality review the conveyance capacity for aquatic species. required in this reach to safely pass floodwaters and to undertake Monitoring continued of the the Flood Frequency Study at aquatic weeds that pass through Morelos Dam. Once this work is the Colorado River. Together with complete, the Commission will be the United States Department of able to consider construction of Agriculture and Mexico’s Colorado works to meet the project's goals. River Irrigation District 014, the

Commission considered the need Aquatic Weeds to reinforce existing control programs for other weeds, such as During 2005, both Sections hydrilla, with the goal of applying actively participated in joint them to control giant salvinia. meetings to study the control of giant salvinia (Salvinia molesta) in the Lower Colorado River, exchanging information on the methods and actions currently being applied, and those proposed for future control of this species.

Aquatic weeds upstream from Morelos Dam. 2005 Annual Report

14 IV.- SANITATION AND WATER QUALITY

Sanitation at San To address sewage in the Tijuana River, which flows north Diego, CA–Tijuana, B.C. into the United States near the SBIWTP, the two Sections During 2005, the IBWC coordinated efforts for the timely continued to undertake activities to attention to occurrences of trans- address sanitation issues at San boundary runoff and discharge Diego, CA-Tijuana, B.C. The IBWC from the Tijuana River and its currently operates the South Bay tributaries. Corresponding mainte- International Wastewater Treat- nance was assured of Pump Station ment Plant (SBIWTP) in San Diego; CILA and the Tijuana River pilot this plant provides advanced channel. This minimized the threat primary treatment of wastewater to public health and the generated in Tijuana. environment by controlling dry- weather discharges into the United States. In accordance with Minute 311, the Commission held internal discussions and international dialogue regarding the proposed construction in Mexico of a secondary treatment plant to provide a higher level of treatment for SBIWTP effluent and to treat additional raw sewage from Tijuana.

The U.S. Section completed various requirements under federal law in the United States, including finishing environmental studies for the project and entering into negotiations with a company to provide required private partici- pation in the project.

Mexico's federal government and the State of Baja California in December 2005 completed the SBIWTP in San Diego, CA ninth of ten annual payments to the United States government through the IBWC to cover Mexico's share of costs associated with the construction of the SBIWTP. Mexico also makes quarterly payments for its share of operation and maintenance costs. 2005 Annual Report

15 IV.- SANITATION AND WATER QUALITY

Sanitation at Calexico, Sanitation at Nogales, CA - Mexicali, B.C. AZ - Nogales, Son.

The Nogales International Substantial progress was Wastewater Treatment Plant made during the year on the (NIWTP), located in Rio Rico, AZ, Mexicali II sanitation project, a was constructed in 1972 within the wastewater collection and treat- framework of IBWC Minute 227 to ment project being constructed by treat wastewater from the Cities of CESPM, the public services utility of Nogales, AZ and Nogales, Son. A Mexicali, B.C. As part of this subsequent agreement, Minute project, the Las Arenitas 276, provided for the expansion of wastewater treatment plant is the NIWTP and allotted to Mexico a expected to begin operations in late treatment capacity at the plant of 2006. 9.9 million gallons per day (434 liters per second). Construction of Mexicali II marks the culmination of many years of work by entities in both During the year ending in countries, including significant early September 2005, the NIWTP leadership by the IBWC. The lack treated 5327.1 million gallons of adequate sanitation infrastruc- (20,165,543.6 cubic meters), with ture in Mexicali has contributed to 63% of the flow from Mexico and contamination of the New River, 37% from the United States. which flows north into the United Mexico paid the costs associated States at Calexico, CA. with treatment of Mexican sewage, including treatment for volumes in In 2005, the monthly excess of the capacity assigned to sanitation inspection visits of the Mexico in Minute 276. In October, a New River continued. Coordinated binational meeting was held to by IBWC, the visits include the address the different aspects of participation of various agencies managing flows in excess of from the United States and Mexico. Mexico’s allotment at the NIWTP. These field visits are conducted for

the purpose of observing the water During the year, work quality conditions of the river and continued on installation of the its tributaries, the existence of un- Supervisory Control and Data controlled wastewater discharges, Acquisition System (SCADA) at the and the sanitation conditions in NIWTP to reduce electrical con- these water bodies and adjacent sumption at the plant and provide areas. plant operators with more control

and better information about the

plant’s performance. Additionally, a contract was issued to remove

sludge from the NIWTP lagoons.

2005 Annual Report

16 IV.- SANITATION AND WATER QUALITY

Four Binational Work Group the City of Nogales, Arizona to meetings were held in 2005 on the overhaul the NIWTP. The main subject of pretreatment for the purpose of the upgrade is to bring Nogales Sister Cities. Pretreat- the plant into compliance with ment refers to the effort to control water quality laws applicable in the the discharge of contaminants into United States. the sewer system -- contaminants that can disrupt the treatment Additionally, a consultant process at the NIWTP. The goal of submitted a report in March on the the meetings was to study possible International Outfall Interceptor cooperative actions for handling (IOI), the 9-mile (14-km) long this issue. pipe that conveys sewage from the international boundary to the In addition, throughout the NIWTP. The report recommended year the IBWC coordinated pipeline rehabilitation to repair delivery to the Nogales, Sonora structural damage and eliminate utility of calcium hypochlorite to infiltration. Implementation of the disinfect the surface water in the IOI rehabilitation is contingent Nogales Wash. upon the availability of funding.

In August a sewer pipe in Sanitation at Naco, AZ - Nogales, Sonora ruptured, sending Naco, Son. millions of gallons of raw sewage into Nogales Wash. Officials on both sides of the border chlori- In 2005 the IBWC nated the flows for disinfection conducted quarterly joint inspec- and the USIBWC put into operation tions of the lagoon wastewater the pumping plant in the wash, treatment system in Naco, Son. which diverted some of the flow for with the objective of observing the treatment at the NIWTP. current conditions of the east side lagoons and the pumping plant that conveys wastewater to the That same month, a sulfuric west side lagoons. In accordance acid spill affected the Santa Cruz with IBWC recommendations, the River, prompting activation of the local utility took measures to Nogales Sister City Emergency protect the lagoons against erosion Response and Preparedness Plan. that was being caused by wave The spill occurred in Mexico after a action. train with tanker cars of sulfuric acid derailed near the river. The IBWC offered support to local The local utility also emergency managers who took replaced the pumps at the sewage steps to protect the public and lift station that had been drinking water. rehabilitated by the U.S. Section in 2000. The new pumps should be In December, the North easier to maintain, improving American Development Bank performance of the wastewater approved a $59 million grant to collection system. 2005 Annual Report

17 IV.- SANITATION AND WATER QUALITY

Sanitation at dollars, out of which the United States contributed $400,000.00. El Paso, TX – Moreover, personnel from both

Ciudad Juarez, Chih. Sections continued to conduct weekly joint inspections of the In response to concerns NLIWTP and prepare associated expressed by residents on both reports. sides of the border about odors emanating from the Ciudad Juarez Water Quality North Wastewater Treatment Plant, the IBWC facilitated bi- Monitoring national meetings to follow up on odor control activities. Binational As part of the Joint visits were also carried out to sites Memorandum, “Recommendation where effluent from the two of an Initial International Program Ciudad Juarez Wastewater Treat- for Observation of the Quality of ment Plants is discharged into the International Waters of the United Rio Grande. States and Mexico,” dated July 5, 1977, the IBWC has been collecting water quality information Follow-up was also per- to assess and address water formed regarding the proposed quality along the border where the Anapra Wastewater Treatment United States and Mexico share Project in Ciudad Juarez. Binational transboundary water resources. meetings and visits to the proposed plant construction site were conducted. In the international reach of the Rio Grande basin, the IBWC Sanitation at Nuevo routinely compiles and exchanges water quality information along the Laredo, Tamps. major urban areas such as El Paso, TX-Ciudad Juarez, Chih.; Del Rio, The Nuevo Laredo Inter- TX-Ciudad Acuña, Coah.; Eagle national Wastewater Treatment Pass, TX - Piedras Negras, Coah.; Plant (NLIWTP) is a binational Roma, TX - Ciudad Miguel Aleman, project constructed in the 1990s Tamps.; Hidalgo, TX - Reynosa, within the framework of the IBWC Tamps.; and Brownsville, TX- to address Rio Grande water quality Matamoros, Tamps. The data concerns in the area of Laredo, TX- indicate that fecal coliform bacteria Nuevo Laredo, Tamps. In accor- are a water quality concern dance with the agreements in downstream of some urban areas Minute 297, the IBWC reached along the international reach of the consensus on the United States Rio Grande. share of the operations and maintenance (O&M) costs for the sanitation system in Nuevo Laredo. The total O&M costs presented for 2005 were $2,537,353.28 U.S. 2005 Annual Report

18 IV.- SANITATION AND WATER QUALITY

Along the New River, which the sister cities of Nogales, AZ - flows from Mexicali, Baja California Nogales, Son., monthly data on north through Calexico, California the quality of the influent and before emptying into the Salton effluent from the Nogales Sea, water quality is monitored for International Wastewater Treat- several parameters in accordance ment Plant (NIWTP) in Arizona was with Minute 264. During 2005, the compiled, exchanged, and distrib- level of dissolved oxygen was not uted to the pertinent authorities. in compliance with the Minute 264 At the NIWTP, effluent that standard. These low levels of exceeds the U.S. permit limits for dissolved oxygen may lead to fish Ammonia-nitrogen and turbidity is kills and create anoxic conditions an ongoing concern. The U.S. leading to loss of aquatic Section has been working with its communities and nuisance partners to improve the level of conditions such as increased odor treatment to meet U.S. permit from organic decomposition. requirements for surface water and Impacts to water quality and comply with the State of Arizona habitat affect this reach and groundwater protection permit concerns have been raised by the limits. local communities regarding the levels of bacteria that could In addition, information is potentially be a health concern to compiled daily on the quality of people who come into contact with water flowing through the Nogales the waters of the New River. Wash, an urban stream that flows from Nogales, Son. into the United States. Significant improvement in The IBWC also collects and the levels of fecal coliform in the exchanges water quality data on Nogales Wash were realized during infrastructure projects along the 2005 due to chlorination of flows in border that affect water quality. the Wash carried out by the State Data is reviewed to determine of Sonora water utility (COAPAES). compliance with the established permit limits for each particular wastewater treatment plant. For

Water quality sampling on Lower Rio Grande tributaries. 2005 Annual Report

19 IV.- SANITATION AND WATER QUALITY

In the San Diego, CA- In the El Paso, TX-Ciudad Tijuana, B.C. region, monthly Juarez, Chih. area, monthly data is water quality data on the Pacific provided to the United States on Ocean at Imperial Beach, CA and the quality of the influent and the Tijuana, B.C. beaches was effluent from the Ciudad Juarez compiled, exchanged, and distrib- North and South Wastewater uted to the pertinent authorities. Treatment Plants that drain into The program includes monitoring Mexico’s irrigation canal system. related to the South Bay Ocean Sampling points within the canal Outfall -- the pipeline that include monitoring stations above discharges effluent from the and below the treatment plants at Commission's South Bay Inter- Km 135 Discharge Drain, El national Wastewater Treatment Guayuco, and Fort Quitman. The Plant (SBIWTP) in San Diego at a canal empties into the Rio Grande point 3.5 miles (5.6 km) offshore below Fort Quitman, Texas. in the Pacific Ocean. The IBWC Likewise, data from El Paso’s South Bay Ocean Monitoring wastewater treatment plants Program includes over 35 stations (WWTP) (Roberto Bustamante along the shore and offshore to WWTP, Haskell R. Street WWTP, monitor water quality and aquatic Northwest WWTP, and the Fred

communities. At the international Hervey Water Reclamation Plant) boundary in the Pacific Ocean, high are provided to Mexico for review.

bacterial concentrations have led to beach closures in the San Diego In Nuevo Laredo, Tamps., region. IBWC Minute 279 establishes water quality standards for the Nuevo Data on the influent and Laredo International Wastewater effluent from the SBIWTP and the Treatment Plant (NLIWTP). The San Antonio de los Buenos NLIWTP meets the standards for Wastewater Treatment Plant in effluent quality on a regular basis; Tijuana were also compiled and it discharges into the Rio Grande exchanged for each month in below the two sister cities of 2005. Laredo, TX-Nuevo Laredo, Tamps.

Effluent from the Nuevo Laredo Inter- national Wastewater Treatment Plant is monitored. 2005 Annual Report

20 V.- OTHER PROJECTS

Desalinization Study Transboundary for the San Diego, CA- Aquifers Tijuana, B.C. Region In the area of ground- In the framework of IBWC water, the IBWC exchanged and Minute 301, support was provided distributed data from wells in the to local authorities for international Yuma Valley and San Luis Rio coordination of the "Feasibility Colorado. Information was Study for the Development of Joint presented on the aquifer in the Seawater Desalinization Oppor- area of the Imperial Valley-Mexicali tunities for the San Diego-Tijuana Valley that would be impacted by Region," which was completed in the lining of the All-American March 2005 and distributed to the Canal. Quarterly drilling was done participating authorities in the in water table sample wells in the United States and Mexico. The area of Amistad Dam. study considered financing options and legal and institutional aspects.

The San Diego County Water Authority (SDCWA) contracted with P.B. Water to develop the study.

Water table sample wells at Amistad Reservoir 2005 Annual Report

21 V.- OTHER PROJECTS

International Bridges • Improvements to the plaza on Water Street in Laredo,

TX. In 2005, the Commission approved the conceptual plan to • Santa Ursula Connector replace the Tornillo, TX-Guadalupe, Project to connect Santa Chih. International Bridge, known Ursula Road to Water Street as the Fabens Bridge, construction on the Rio Grande floodplain of which is proposed 1900 feet in Laredo, TX. (594 m) upstream from the • Construction of an overpass current bridge over the Rio above the Rio Grande levee Grande. Similarly, support was in Reynosa, Tamps. for the given in the form of data and field road known as the activities for development of Libramiento Oriente. preliminary projects for the following proposed international • Remodeling and expansion of bridges: Laredo, TX-Nuevo Laredo, the Reynosa, Tamps. Tamps. No. V; the second Del Rio, Customs Office as part of the TX-Ciudad Acuña, Coah. Aduana Modelo project. International Bridge; and the • Phase III construction and Westrail International Railroad renovation of Las Tortugas Bridge in Brownsville, TX- Park in Ciudad Juarez, Chih. Matamoros, Tamps. • Construction of a roadway in Eagle Pass, TX, part of which is located in the Rio Grande Tecate Port of Entry floodplain. • Construction of the Nuevo During 2005, the port of Laredo, Tamps. Municipal entry at Tecate, CA-Tecate, B.C. Storm Drainage Collectors, was renovated. Due to construc- including construction of the tion of the new port's northbound following stormwater collec- entry gates, an auxiliary boundary tion drains that discharge into marker was removed. In its place, the Rio Grande: 15 de brass caps were installed on either Septiembre (North and side of the new northbound gate. South), Campeche, Indepen- dencia, Riva Palacio, and

Canal Concordia.

Projects on the Rio Tijuana River Flood Grande Floodplain Control Project

In 2005, the Commission The telemetry system reviewed and approved the installed by the IBWC in the following projects within the Tijuana River basin and at the floodplain of the Rio Grande: Abelardo L. Rodriguez Dam was active and operational throughout 2005 Annual Report

22 V.- OTHER PROJECTS the year, demonstrating its Mexico. The IBWC would coordinate effectiveness during the rainy international efforts for the season. This system enables the installation of the system in Mexico water elevation and rainfall at and for financial transactions from Rodriguez Dam to be measured in the USACE to Mexico for the near real time, providing timely and operational costs of the system in reliable data. Rodriguez Dam is a Mexico. Funding is not expected for small Mexican reservoir in the a number of years. Tijuana River that plays a key role in the flood control system for To advance this effort, the Tijuana and downstream interests Nogales Wash Flood Control Study, in San Diego. It is part of the developed under the framework of binational Tijuana River Flood the Commission, was revised and Control Project, which includes a distributed to interested authorities. concrete-lined river channel and The purpose of the study was: levees. The IBWC looked at the possibility of installing a new 1) to identify the nature of remote station at Matanuco Arroyo, the current flood problem in downstream from the Abelardo L. Nogales, Sonora; Rodriguez Dam, in order to accurately measure releases and 2) to develop measures that leakage from the dam but the might potentially reduce the threat project has not yet been of flooding; and implemented. 3) to analyze and compare alternatives to reduce potential Nogales Flood Control flood damage. Project

The IBWC maintained formal communication with relevant authorities regarding the proposed installation of the Nogales Flood Warning System (NFWS). The NFWS would consist of rain and stream flow gages located at key areas in the Nogales Wash basin in Nogales, AZ-Nogales, Son. Funding for purchase and installation of all gaging and communication equip- ment would be from the United States Army Corps of Engineers (USACE), the agency responsible for most federal flood control projects in the United States. The Maintenance of the Nogales Wash USACE would also fund normal in Sonora. operational costs for this system in 2005 Annual Report

23 2005 PROJECT MAP

Projects of the International Boundary and Water Commission Included in the 2005 Annual Repo1

C A L I F ORN I A ARIZONA

e LOS ANGElES

OfDIO

FIHOENtX

COOUOG£ DA.W C f t A ,...... T ..

L()RO$....

.. S 0 N 0 R A 0 . "

C H I H 1. San Diego- Tijuana SanllaUon - Saneamiento de Tijuana- San Diego 2. Tijuana River Flood Control - Control de Avenidas en el RTo 'Njuona 3. Water Supply for lhe City of Tijuana - Abast.ecimicnlo de Agua para la Ciudad de Tijuana 4. Tecate Port or Entry - Puerto de Entrada de Tecate 5. Calexico-Mexicali Sa nitation - Sanea.mienlo de Mexicali-Calexico 6. All- American Canal - Canal Todo Americana 7. Colorado River Della - Della del Rio Colorado 8 . Colorado River Water Deliveries, Morelos Dam, Wellton-Mohawk Drain, Salinity - Entregas de Agua del Rfo Colorado, Presa Morelos, Dren Wellton- Mohawk, Salinidad 9. Nogales Sanil alion, Nogales Flood Control Project - Sanearnienlo de Nogales, Control de Avenidas en Nogales 10. Naco Se.nilalloo - Saneamienlo de Naco 11. Convention or 1906, Upper Rio Grande Flood Control, SanitaUon e.l El Paso- Cd. Juarez - Convencl6n de 1906, Control de Avenidas en el Alto Rio Bravo, Saneamienlo de Cd. Juarez-El Paso 12. Presidio, TX- Ojinaga, Chih. - Ojmaga, Chih.-Presidio, TX 13. Waler Conservation Projecls - Proyeclos de Ahorro de Agua "\ 14. Environmental Preservation of lhe Rio Grande - Preservaci6n Arnbiental del Rio Bravo /~ 15. Amlslad Dam - Presa La Amistad 16. Nuevo Laredo Sanitation - Saneamiento de Nuevo Laredo 17. F'alcon Dam - Presa F'alc6n 18. Aqualic Weeds - Maleza Acu6lica 19. Anzalduas Darn - Prese. AnzaldO..as 20. Relamal Dam - Presa Retamal 21. El Morillo Dram - Oren El Mortllo 22. Brownsvi.Lie- Malamoros Weir - Represa Matemoros- Brownsville - Lower Rio Grande Flood Control - Control de Avenidas en cl Bajo RTo Bravo 2005 Annual Report

24 MAPA DE PROYECTOS 2005

1 I Proyectos de Ia Comisi6n lnternacional de Umites y Aguas lncluidos en el lnforme Anual 2005

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/ NUEVO LEON J \. ...,v- " '-./ WONl[RII:(Y., SAN ~u.. ~ ,f

r D U R A N G 0 / I ') /\ 2005 Annual Report

25