METHODOLOGY


  • Use of RAINFLO, a hydrologic rainfall-runoff model developed by the author to emulate the U.S. Army Corps of Engineers HEC-1 standard.

  • Determination of the topology of the drainage network.

  • Conversion of the 1:50,000-scale maps of the Mexican cartography (INEGI) to the 1:24,000 scale of United States cartography (USGS).

  • Conversion of the data to the metric system.

  • Compilation of California precipitation data for return periods from 2 to 100 yr.

  • Extension of the precipitation data to return periods of 200, 500 and 1000 yr.

  • Selection of the SCS storm type I, applicable to Southern California.

  • Calculation of the maximum mean monthly levels in Morena and Barrett reservoirs.

  • Collection of cartographic data for soil type and land use in California.

  • Evaluation, using stereoscopic pairs, photographic mosaics and field visits, of the soil type and land use conditions in the Mexican portion of the basin.

  • Evaluation of the average land slope and average stream slope in the drainage network of Cottonwood Creek - Arroyo Alamar.

  • Evaluation of typical cross-sections.

  • Model runs for the 2-, 5-, 10-, 25-, 50-, 100-, 200-, 500-, and 1000-yr frequencies, using the maximum average monthly level in Morena and Barrett reservoirs.

  • Model runs for the 2-, 5-, 10-, 25-, 50-, 100-, 200-, 500-, and 1000-yr frequencies, assuming zero infiltration in the project channelization reach. This is necessary to evaluate the impact of a postulated concrete channel on the aquifer recharge.


 
Pine Valley Creek downstream of the bridge at Old Highway 80
 

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DATA MANAGEMENT
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