Water planning in semi-arid regions depends on climate information that resolves both seasonal timing and topographic gradients. This study evaluated 15 CMIP6 models over Zacatecas, Mexico, and produced a 1 km historical dataset for 1985–2014 by statistically refining bias-corrected daily fields from NEX-GDDP-CMIP6. Downscaling was referenced to the CHELSA climatology: temperature was refined using an elevation-informed hybrid spline approach, whereas rainfall was downscaled with geographically weighted regression (GWR) to represent orographic gradients. The resulting fields were assessed against two independent observational baselines: an automated INIFAP network (2004–2014) and a conventional CONAGUA network (1985–2014). For temperature, BCC-CSM2-MR showed the highest performance, with a Pearson correlation of R = 0.94 for both T_max and T_min. A consistent network-dependent bias pattern was identified: the downscaled models overestimated the diurnal temperature range relative to INIFAP but underestimated it relative to CONAGUA, highlighting the influence of instrumentation and observational protocols on model evaluation. For rainfall, ACCESS-ESM1-5 reproduced the seasonal cycle and dominant orographic patterns, with a correlation of R = 0.611 despite the intrinsic stochasticity of semi-arid rainfall. The resulting 1 km fields provide a spatially consistent baseline for regional applications, including stochastic weather generation and impact models in complex semi-arid regions.

Mineral scale deposits in groundwater-supplied drinking water distribution systems reduce hydraulic efficiency and increase maintenance costs. This study evaluated the effectiveness of citric acid as a descaling agent for natural scale deposits collected from the Benito Juárez and La Joya drinking water distribution systems in Zacatecas, Mexico. The samples were treated with citric acid solutions at concentrations of 1, 2, and 3 M (moles per liter) and characterized before and after treatment using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and inductively coupled plasma optical emission spectrometry (ICP-OES). In addition, statistical analyses were performed using analysis of variance (ANOVA) and Tukey’s test. The scale deposits were composed mainly of calcium carbonate and exhibited differences in their initial mineralogical composition between the two systems. Treatment with citric acid promoted the progressive dissolution of carbonate phases, resulting in mineralogical, chemical, and morphological changes. The 3 M solution produced the highest degree of mineral dissolution, whereas the 1 M and 2 M treatments showed statistically similar behavior. The results demonstrate that scale deposit removal efficiency is influenced by the initial composition of the scale deposits, providing a scientific basis for optimizing remediation strategies in drinking water distribution systems.