Status of water-level altitudes and long-term and short-term water-level changes in the Chicot and Evangeline (undifferentiated) and Jasper aquifers, greater Houston area, Texas, 2022

Abstract

For an overview of USGS information products, including maps, imagery, and publications, visit https://store.usgs.gov/.

Status of water-level altitudes and long-term and short-term water-level changes in the Chicot and Evangeline (undifferentiated) and Jasper aquifers, greater Houston area, Texas, 2023

“…To depict the upper and lower bounds of the data on each map, the water-level-altitude increment for the first bin and for the last bin for a given map extends to the lowest and highest estimated water-levelaltitude value, respectively. The shaded grids are published in a companion data release (Ramage, 2023b). The water-levelaltitude grids are approximate, regional-scale depictions of the water-level altitudes in the Chicot and Evangeline (undifferentiated) and Jasper aquifers.…”

“…If the computed variance at any given grid cell is less than or equal to the overall mean variance for each respective gridded surface for the current year and historical year, the data are deemed valid for inclusion in the mapped area depicting water-level change (Ramage and others, 2022). The datasets of water-level-change values (difference between 2023 and historical year water-level-altitude values) are available in Ramage (2023b); the grids and their associated variance distribution maps that were produced from the water-level data collected from the network of wells (along with a description of the processes by which these datasets were produced) are included in Ramage (2023a, b).…”

“…A much smaller proportion of the wells were excluded when constructing the water-level-altitude maps because they were not consistent with water-level altitudes obtained from nearby wells screened in the same aquifer for one of the following reasons: (1) the water level measured in the well in question differed appreciably from the water levels measured in wells in the surrounding area and was deemed to be erroneous or (2) water had been withdrawn recently from the well in question, temporarily lowering its static water-level altitude. A companion data release by Ramage (2023b) identifies the water-level measurements that were used to construct the maps of water-level altitudes and water-level changes for each aquifer. Of the 638 wells in the study area where waterlevel measurements were collected or 10-year median values were computed, 613 are screened in the Chicot, Chicot and Evangeline, Evangeline, or Jasper aquifers; of these 613 wells, the well depths were 250 ft or less in 36 wells.…”

“…Water-level-measurement data from 479 wells (Ramage, 2023b) were used to depict the 2023 water-level altitudes for the Chicot and Evangeline aquifers (undifferentiated) (fig. 4).…”