FEASIBILITY OF PUMPING TO PROVIDE WATER
FOR TECATE RIVER PARK

Proposal

Victor M. Ponce

June 4, 2004


BACKGROUND

The Comisión Estatal de Servicios Publicos de Tecate (CESPTE) is considering pumping a certain amount of water a distance of about 9 km. The objective is to provide surface and groundwater for the Tecate River Park (Río Parque de Tecate). The proposed pumping scheme will lift the flow from the water treatment plant, at elevation 495 m, to the Cerro de la Nopalera, at elevation 590 m, for a total head recovery of 95 m. From this point, it will be conveyed by gravity to the vicinity of Puente San José, the upstream point of the project.

The minimum amount of water currently being considered is 40 L/s, although there is a potential to increase the flow to 200 L/s, depending on future water availability and policy.

There is a need to establish the feasibility of this pumping scheme considering water availability in space and time, start-up and maintenance costs, perceived and assured benefits, and impact of the pumping scheme on the surface water, groundwater, and vegetation resources of the proposed river park.

PROBLEM STATEMENT

The Tecate River immediately downstream of San Jose Bridge is about 10 m wide. Further downstream, at El Descanso, it is about 60 m wide. Studies are required to determine the impact of varying amounts of pumped flow, from 40 to 200 L/s, on the hydrology, hydraulics, and vegetational resources of the study reach at El Descanso.

Specific questions to be addressed by the research are the following:

  1. What is the fate of the pumped flow once it is discharged at Puente San Jose? How fast will it infiltrate? How deep will it infiltrate?

  2. Will it benefit surface water? To what extent?

  3. Will it benefit groundwater? To what extent?

  4. Will it foster the establishment of hydrophytic and hygrophytic vegetation in the low-flow channel?

  5. Will it foster the establishment of riparian vegetation along the channel banks?

  6. To what longitudinal extent, downstream of Puente San Jose, will amounts varying from 40 L/s to 200 L/s of pumped flow will impact the water flow and vegetational resources in the proposed river park?

  7. What other discharge points could be considered in lieu of Puente San Jose?

PROPOSED STUDIES

To accomplish the objectives, the following focused studies are proposed:

  1. Hydrology

    • Determine temporal, seasonal, annual, and spatial variability of pumped flow quantity.

    • Determine suitable flow increments for study.

  2. Hydraulics

    • Evaluate infiltration velocities of channel bed, by means of grainsize analysis of selected channel bed samples, complemented with ground truth with field measurements of hydraulic conductivity.

    • Calculate initial flow depth in the low-flow channel.

    • Route pumped flow quantity through channel reach, considering channel transmission losses, to determine extent of channel infiltration.

    • Determine fate of infiltrated water, either to remain in the vadose zone or to reach the water table.

  3. Vegetation Science

    • Appraise native and introduced vegetation types in the low-flow and high-flow channels of proposed Tecate River Park downstream of Puente San Jose.

    • Evaluate extent to which imported surface and groundwater, in the specified amounts, will foster the permanence of different types of channel and riparian vegetation.

METHODOLOGY

To following methodologies are considered:

  1. Hydrology

    • Evaluate water availability, in consultation with CESPTE staff, in the 5-, 10- and 20-yr planning horizons.

    • Establish five flow increments, ranging from minimum to maximum, based on water availability study.

  2. Hydraulics

    • Sample channel bed in a minimum of ten (10) locations.

    • Perform grainsize analysis of channel-bed samples to determine sand size: coarse, medium, or fine [a minimum of ten (10) tests].

    • Perform field tests to determine hydraulic conductivity [a minimum of three (3) tests].

    • Establish typical cross-sections in study reach by field surveys [a minimum of ten (10) cross sections].

    • Use hydraulic principles to determine flow depth for design flows, based on typical cross sections.

    • Use channel routing model to route the flows through the study reach, considering abstraction by channel transmission losses.

    • Determine resulting surface flow hydrographs in the study reach.

    • Evaluate mean depth to the water table and its seasonal variation.

    • Evaluate infiltrated flow amounts and their fate.

    • Evaluate surface water-groundwater-vegetation interaction to determine impact of scheme on park vegetation.

    Sampling of the channel bed will be made with grab samples, to a depth of 30 cm. Samples will be properly labeled and shipped to the SDSU Geotechnical Laboratory for moisture content and grainsize analysis. Results of the lab tests will be compared with the grainsize analysis performed by Rhoda Arkos Ingenieria, S.C. as part of the "Estudio Hidrológico del Río Tecate".

    Field tests to determine hydraulic conductivity will be made following standard procedures established by the Agricultural Research Service. The two-concentric-cylinder method will be used. Field testing equipment for hydraulic conductivity will be manufactured locally in Tecate.

    Typical cross sections will be chosen based on available maps, and measured with survey tape.

    Flow depths will be determined using hydraulic principles of flow in open channels. Channel routing methodologies will be used to route flows through study reach. Channel abstractions at the appropriate hydraulic conductivity rate will be an intrinsic part of the channel routing computation. Infiltrated flow amounts will be evaluated by subtraction from source flows.

    Depth to water table will be measured at a minimum of five (5) locations using an auger sampler.

    Surface-groundwater-vegetation interaction will be evaluated by assessing the changes in moisture content with and without pumping the source flows. These changes in moisture content will be related to the shape of the cross section, the existence of riparian and other vegetation, and their natural requirements for moisture.

    The location where CESPTE is discharging treated water at the bottom of Cerro de la Nopalera will be examined for its hydrology and vegetation relations.

  3. Vegetation Science

    • Characterize, through field surveys and local experience, the native and introduced vegetation in the study reach.

    • Survey the quality of the vegetational communities PRIOR to the establishment of the pumping scheme.

    • Evaluate surface water-groundwater-vegetation interaction to determine impact of scheme on park vegetation.

    • Assess the quality of the vegetational communities AFTER the establishment of the pumping scheme.

RESEARCH TEAM

The research team is comprised of the following persons:

  • Dr. Victor M. Ponce, principal investigator, professor of civil and environmental engineering, San Diego State University. Dr. Ponce will coordinate the project and participate in the execution of the work. He will be responsible for coordination with Mexican counterparts and local officials. He will be responsible for executing the hydrologic modeling and the analysis thereof.

  • Ana Elena Espinoza, Director, Centro de Estudios Urbanos Sociales y Sustentables (CEUSS), Tijuana, Baja California. Ms. Espinoza will be responsible for providing the urban planning and field expertise on Tecate Creek required to carry out the project effectively and in a timely manner. She will assist Dr. Ponce and his staff with field data, field work, vegetation surveys, and coordination with local officials.

  • Flor Perez, research assistant, San Diego State University Foundation. Ms. Perez will be responsible for the field and laboratory work. Ms. Perez is an engineering student from IPN-ESIME (Culhuacán-Mexico), on a research assignment at SDSU.

TIMETABLE AND DELIVERABLES

The timetable for this project is four months. A detailed schedule follows:

  • First month (June 2004): Data collection, field sampling, and field tests.

  • Second month (July 2004): Data analysis and modeling.

  • Third month (September 2004): Project documentation.
The report will include specific recommendations for optimal locations of treated water discharge, flow rates, seasonal variations, and riparian vegetation establishment and enhancement.

The deliverables include the following:

  1. A web-based report with full documentation of background, objectives, methodologies, analysis, results, conclusions, and recommendations.

  2. A hard-copy report (grayscale) with full documentation of background, objectives, methodologies, analysis, results, conclusions, and recommendations.

  3. An electronic version of the report in CD-ROM.

  4. A summary report (in English and Spanish) to the funding agency documenting in layperson's terms the conclusions and recommendations of the study.

BUDGET

The estimated budget follows.

Personnel
V. M. Ponce (1 month) 10,429
F. Perez (200 hr @ $15/hr) 3000
Fringe benefits (Ponce @22%, Perez @25%) 3044
Total Personnel 16,473
Travel
Mileage (200 mi × $0.375 × 10 trips) 750
Per diem ($46/day × 10 days × 2 ppl) 920
Total Travel 1670
Supplies
Office supplies 279
Field and laboratory tests 1200
Total Supplies 1479
Contractors
Ana Elena Espinoza 3000
Total Contractors 3000

Total Direct Costs 22,622