This paper uses simple hydro-economic optimization to investigate a wide range of regional water system management options for northern Baja California, Mexico. Hydro-economic optimization models, even with parsimonious model formulations, enable investigation of promising water management portfolios for supplying water to agricultural, environmental and urban users. CALVIN, a generalized hydro-economic model, is used in a case study of Baja California. This drought-prone region faces significant challenges to supply water to agriculture and its fast growing border cities. Water management portfolios include water markets, wastewater reuse, seawater desalination and infrastructure expansions. Water markets provide the flexibility to meet future urban demands; however conveyance capacity limits their use. Wastewater reuse and conveyance expansions are economically promising. At current costs desalination is currently uneconomical for Baja California compared to other alternatives. Even simple hydro-economic models suggest ways to increase efficiency of water management in water scarce areas, and provide an economic basis for evaluating long-term water management solutions

Irrigated agriculture is the largest water user in many regions, and agricultural water use efficiency and consumption has been studied by several authors. This paper provides a framework and application of economic valuation of water for agriculture in three regions in northern Baja California, Mexico, namely Guadalupe, Maneadero and Mexicali Valleys. Positive mathematical programming (PMP), a deductive valuation technique, was the framework used for this estimation using water delivery data reported by the National Water Commission in Mexicali, production costs and cultivated area, production factors use from the Agriculture Ministry (SAGARPA); and other data from previous studies. Analysis of the results shows that marginal economic water value in Mexicali is at least 2.6 times the water price paid by farmers. Guadalupe and Maneadero with higher value agriculture, have higher marginal economic values of water than Mexicali, albeit closer to their water costs. Small shortages increase this economic value for farmers. Estimated price elasticities of irrigation water for each turn-out are inelastic for all regions and within the range of most previous studies. Policies aimed to reduce water consumption by decreasing current pumping subsidies are encouraged.

An atmospheric condition known as a ‘Santa Ana’ wind occurred from 9 to 11 February 2002. Its effect was felt over a large portion of southern California and the northern half of the Baja California Peninsula. Santa Ana winds are dry, strong northwesterly through easterly mountain downslope winds, most common in winter. Satellite data from Quickscat show two large wind jets crossing the mountains of the peninsula and extending 300 km offshore. Data from a coastal station reveal that the event lasted over 52 h with average speeds of 11 m s−1 and gusts of 25 m s−1. The southernmost jet crosses the mountains at the San Matias mountain pass and generates a cold filament off Point Colonet. Satellite imagery shows this feature lasting at least two inertial periods (Ti = 22 h) and extending 100 km offshore during the observation period. Estimates of the stationary Ekman pumping produced vertical speeds of 20 m per day, consistent in time and location with the observed structures. The ocean off Point Colonet is well known for the existence of upwelling episodes. They occur mostly in the spring or early summer when persistent winds blow towards the equator and parallel to the coast. The events described here present a different phenomenon: upwelling filaments induced by short-lived, offshore winter winds

Based on a total of 135 stable isotope analysis (δ18O, δD) carried out on surface and groundwater samples, as well as on rainwater samples between 2004 and 2011 in 5 different regions in Baja California, an isotopic evaluation of the region was established. The results showed a depletion gradient of -0.25 ‰ δ18O per 100 m rise in elevation throughout the study area. Considering an unaltered δ18O signature for the thermal springs, the recharge areas of these waters are at elevations over 1400 m outside of the present watersheds, indicating the presence of regional flow systems next to the local flow regime feeding the cold springs and wells. The Mesa de Andrade area has a completely different signature with values of -105 for δ18O and -13 for δD.

Around the world, groundwater constitutes approximately 94% of the total volume of freshwater, providing a wide range of economic and environmental services. In Baja California, Mexico, groundwater provides around 60% of the required demand and has become an essential source for agriculture, industry and domestic use. Particularly, in the Guadalupe Valley, in the municipality of Ensenada, the development of diverse activities depends on the water stored in the aquifer. Among these activities, agroindustry stands out; due to its high value, it represents a regional development factor. The objective of this research consisted of identifying potential aquifer recharge sites as tools for the planning process for regional socio-economic development. The study consisted of four fundamental parts: (1) Compilation and identification of entry data of the recharge model; (2) identification and evaluation of the sites that have a greater or lesser capacity of water recharge, using a geographic information system (GIS); (3) comparison of the model results with the piezometric data of two wells in the study area and their relationship with precipitation events; (4) finally, the development planning instruments of the study area were identified, and the relevance of the present study as a planning tool was evaluated. The results obtained showed that 16.31% and 3.64% of the area presents a high and very high recharge potential, respectively. This article is useful for the authorities and users to develop projects for aquifer recharge in the Guadalupe Valley.

A two-dimensional algorithm for underground water flow simulation was modified and adapted to the geohydrologic conditions of the Guadalupe valley located in the state of Baja California in northern México. In order to solve the numerical model using the balance equation, the central finite differences with spatial and temporal constant increments method were used. Such model considers a heterogeneous and transient unconfined aquifer. Modeling and calibration processes are presented using the data of water table levels provided by the water level data loggers installed in a monitoring network and precipitation data from climatic stations of both seasons: 2009-2010 and 2010-2011. It was possible to locate, correlate and model specific rainfall-recharge events with the aim of obtaining an estimation of how these events are directly reflected on the water table level of the aquifer and how it reacts against simulated extraordinary events.

In order to recognize the soil and geomorphologic characteristics of the northeastern part of Valle de Guadalupe, Baja California, and its implications on the runoff volumes in the region, 59 soil samples were collected from the first 5 cm of the soil layer, taking into account the surface relief, soil classification and vegetation cover of each sampling point. Soil moisture content and textural analyses were carried out in the laboratory for each sample. Three raster images were used to complement field data: an Ikonos image, an Aster Image and the Instituto Nacional de Estadística Geografía e Informática digital geologic map I11D82. The Ikonos image was used to calculate the normalized differential vegetation index, the Aster image to evaluate the field slope, and the digital map to obtain geologic information for the study area. Following the runoff curve number method, a computational algorithm was developed (for Ermapper 6.4 software), by using the three raster images and the field data. The algorithm was employed to study the surface runoff potential in the Serranía Matcuatai and to evaluate its runoff volume contributions to Valle de Guadalupe. The mean annual runoff volume contribution was estimated in 258,000 ± 123,000 m³. It was also found that 88% of the study area surface has a runoff potential and only 12% is favorable to infiltration.

The amount of sediment drained into the Pacific coast due to the orographic system of northem Baja California was estimated by indirect methods. Langbein and Schumm’s (1958) equation was used to relate the erosive action of the rain and the protective action of the vegetation. Statistics on pluvial precipitation for 1950 to 1983 of 21 stations of the Secretaria de Agricultura y Recursos Hidráulicos were used. Furthermore, topographical data of 44 charts of the Instituto Nacional de Estadística, Geografía e Informática (INEGI), corresponding to the northem area of Baja California, were digitized on a PRIME 750 computer and processed with a program (TOPOGRAFIC) developed at the Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE). Two drainage basins were identified as maximum potential sources of sediment: the Tijuana River basin (S = 809649.88 tons/year) and the Guadalupe River basin (S = 834889.13 tons/year). According to the model, these are not maximum values. Higher values can be expected with greater rainfall and we thereforeconsider this area to be one of high geological risk.

The amount of groundwater recharge by channel infiltration is estimated for El Barbon basin, in Baja California, Mexico. The basin’s lower portion includes the valleys of Ojos Negros and Real del Castillo Viejo, which are crossed by several ephemeral washes, including the mainstem El Barbon Wash. A distributed catchment model with the capability for nonlinear channel routing and channel abstraction is used to calculate groundwater recharge by channel infiltration for storm events of 2-, 5-, 10-, 25-, 50-, and 100-yr return period. The results confirm that event channel infiltration can be a substantial component of the vertical recharge. q 1999 Elsevier Science B.V. All rights reserved.

The amount of groundwater recharge by channel infiltration is estimated for El Barbon basin, in Baja California, Mexico. The basin’s lower portion includes the valleys of Ojos Negros and Real del Castillo Viejo, which are crossed by several ephemeral washes, including the mainstem El Barbon Wash. A distributed catchment model with the capability for nonlinear channel routing and channel abstraction is used to calculate groundwater recharge by channel infiltration for storm events of 2-, 5-, 10-, 25-, 50-, and 100-yr return period. The results confirm that event channel infiltration can be a substantial component of the vertical recharge. q 1999 Elsevier Science B.V. All rights reserved.