Data on the hydrologic properties of aquifers are frequently not available or are spatially limited; additionally, their determination through aquifer tests is often logistically complicated and economically expensive. This study aimed to estimate aquifer properties by analyzing the water level response for the effects of barometric pressure and earth tide. Harmonic analysis of the time series of water level and barometric pressure recorded in three boreholes in the Mexicali aquifer provided reasonable values of porosity, specific storage, transmissivity, and compressibility of the rock materials that constitute the alluvial aquifer. The representative values of porosity (14–20%), specific storage (1.74–6.23 × 10⁻⁶ m^–1), transmissivity (8.57–8.66 × 10⁻⁷ m²·s^–1), and compressibility (3.90–8.21 × 10⁻¹⁰ Pa^–1) were obtained. These values were consistent with the sediment types identified in the proximity of the wells analyzed. The results of this study show that the analysis of water level response to natural phenomena is a low-cost tool that provides reasonable estimates of aquifer properties. This advantage is particularly relevant in the study of aquifers where the available hydrological information is insufficient.

Located in northwest Baja California, Mexico, the Guadalupe River Basin is situated in a semiarid region where periods of drought pose serious economic, social and environmental concerns. The study area has highly variable climate, with mean annual precipitation ranging from less than 12 mm to over 750 mm a year across the basin, and with most of the annual precipitation occurring during the autumn and winter seasons. To quantify the frequency and severity of meteorological droughts at the local (watershed) scale, this study investigates seasonal and annual precipitation data from 34 sites in northwest Baja California. Along with the analysis of precipitation climatology and interannual variability, El Niño/Southern Oscillation (ENSO) and related Pacific Ocean sea surface temperature (SST) patterns are shown to be potential predictors of seasonal precipitation. Analysis of precipitation variability at seasonal and annual time scales is performed using the standardized precipitation index (SPI) methodology, and annual, seasonal, and ENSO‐conditioned precipitation frequency analyses are executed using the regional L‐moment algorithm. The SPI and regional rainfall drought frequency estimates developed in this study may be useful for monitoring meteorological droughts and could serve as critical components of a comprehensive drought management plan. Furthermore, the methods applied in this study may be transferred to other semi‐arid locations to mitigate drought risk and, potentially, impacts of drier conditions in the 21st century. Copyright © 2011 Royal Meteorological Society

The demand for groundwater resources in arid and semi-arid regions has increased due to their progressive use in agriculture, industry and domestic activities. Among the difficulties and uncertainties that arise when managing groundwater resources is the calculation of groundwater withdrawals (GWW). The objective of this research work is to review the existing literature on the methods developed to estimate GWW by providing a summary of the advances, limitations and opportunities that the different methods developed on this topic could offer by identifying, categorizing and synthesizing the studies with a focus on developing a systematic guide so that researchers and practitioners conducting GWW studies can be informed of the most popular techniques, and the authors’ experiences in recent years. Therefore, a literature search was conducted in the EEE, Google Scholar, SCOPUS, SpringerLink, ScienceDirect, Taylor & Francis Group and Wiley-Blackwell databases, using the following keywords: Groundwater AND (Withdrawal OR Pumping OR Abstraction) AND (Prediction OR Estimation). Thirty-four journal articles published between 1970 and 2021 were chosen based on the selection criteria, characteristics and capabilities of the approaches used for evaluation in GWW extraction. We concluded that the different methods for groundwater pumping estimation that have been reviewed in this work have advantages and disadvantages in their application. Direct approaches are very old and are still working uncertainty in their application is presented with possible human errors or in the measurement system. On the other hand, indirect methods have evolved along with technological advances, which have brought significant improvements and accuracy to these approaches.