Last updated: September 16, 2025
Article
Climate and Water Monitoring at Casa Grande Ruins National Monument: Water Year 2024
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Overview
Together, climate and hydrology shape ecosystems and the services they provide, particularly in arid and semi-arid ecosystems. Understanding changes in climate, groundwater, and surface water is key to assessing the condition of park natural resources—and often, cultural resources.
At Casa Grande Ruins National Monument (Figure 1), Sonoran Desert Inventory and Monitoring Network scientists study how ecosystems may be changing by taking measurements of key resources, or “vital signs,” year after year—much as a doctor keeps track of a patient’s vital signs. This long-term ecological monitoring provides early warning of potential resource problems, allowing managers to mitigate them before they become worse. At Casa Grande Ruins National Monument we monitor climate and groundwater, among other vital signs.
Groundwater conditions are closely related to climate conditions. Because they are better understood together, we report on climate in conjunction with groundwater. Reporting is by water year (WY), which begins in October of the previous calendar year and goes through September of the water year (e.g., WY2024 runs from October 2023 through September 2024). This web report presents the results of climate and groundwater monitoring at Casa Grande Ruins National Monument in WY2024.
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Climate and Weather
There is often confusion over the terms “weather” and “climate.” In short, weather describes instantaneous meteorological conditions (e.g., it’s currently raining or snowing, it’s a hot or frigid day). Climate reflects patterns of weather at a given place over longer periods of time (seasons to years). Climate is the primary driver of ecological processes on earth. Climate and weather information provide context for understanding the status or condition of other park resources.
Methods
A National Oceanic and Atmospheric Administration (NOAA) Cooperative Observer Program (COOP) weather station, Casa Grande 021314, has been operational at Casa Grande Ruins National Monument since 1906 (see Figure 1). This station typically provides a reliable climate dataset. However, in WY2022 the station was missing data for 40 days. As a substitute, climate analyses for this report use 30-year averages (1991–2020) and gridded surface meteorological (GRIDMET) data from the location of the station. Subsequent reports may revert to the weather stations as the data source, depending on future data quality.
GRIDMET is a spatial climate dataset at a 4 km resolution that is interpolated using weather station data, topography, and other observational and modeled land-surface data. Temperature and precipitation estimated from GRIDMET may vary from actual weather at a particular location, depending on the availability of weather station data and the difference in elevation between the location and that assigned to a grid cell. Data from both the weather stations and GRIDMET are accessible through Climate Analyzer.
Results for Water Year 2022
Precipitation
Annual precipitation at Casa Grande Ruins National Monument in WY2022 was 7.40″ (18.8 cm; Figure 2), which was 0.27″ (0.7 cm) less than the 1991–2020 annual average. Monthly precipitation in WY2022 during the monsoon season and December was higher than the 1991–2020 averages, especially in June, which received 0.69″ (1.8 cm)—nearly eight times the average rainfall. All other months received no rainfall or ≤ 41% of the 1991–2020 averages.
Air Temperature
The mean annual maximum temperature at Casa Grande Ruins National Monument in WY2022 was 88.5°F (31.4°C), 1.2°F (0.6°C) above the 1991–2020 average. The mean annual minimum temperature in WY2022 was 57.3°F (14.1°C), 1.4°F (0.8°C) above the 1991–2020 average. Mean monthly maximum and minimum temperatures in WY2022 were generally warmer than the 1991–2020 monthly averages, differing by as much as 6.8°F (3.8°C; see November as an example, Figure 2).
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Drought
Reconnaissance drought index (Tsakiris and Vangelis 2005) provides a measure of drought severity and extent relative to the long-term climate. It is based on the ratio of average precipitation to average potential evapotranspiration (the amount of water loss that would occur from evaporation and plant transpiration if the water supply was unlimited) over short periods of time (seasons to years). The reconnaissance drought index for Casa Grande Ruins National Monument indicates that WY2022 was slightly drier than the 1991–2022 average from the perspective of both precipitation and potential evapotranspiration (Figure 3).
Reference: Tsakiris G., and H. Vangelis. 2005. Establishing a drought index incorporating evapotranspiration. European Water 9: 3–11.
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Groundwater
Groundwater is one of the most critical natural resources of the American Southwest and Southern Plains. It provides drinking water, irrigates crops, and sustains rivers, streams, and springs throughout the region.
Methods
Pecos National Historical Park groundwater is monitored in two wells (Figure 1). The New Mexico Bureau of Geology and Mineral Resources began monitoring both wells in 2020. The well at the trading post (WL-0206) is monitored annually, after previously being monitored continuously and the well at the Glorieta Battlefield Trail (WL-0207) is also monitored annually. The data are available at the
Healy Collaborative Groundwater Monitoring Network.
Results
Groundwater levels in WY2024 were stable and relatively shallow (Table 1 and Figure 4). The mean depth to water at WL-0206 was 41.33 feet below ground surface (ft bgs; 12.60 m bgs), slightly higher than the previous water year. The depth to water at WL-0207 was 34.14 ft bgs (10.41 m bgs), slightly lower than the previous measurement.
Table 1. Groundwater monitoring results in water year (WY) 2024, Pecos National Historical Park (amsl = above mean sea level; bgs = below ground surface).
| State Well Number | Location | Wellhead Elevation (ft amsl) |
Mean Depth to Water (ft bgs) |
Mean Water Level Elevation (ft amsl) |
Change in Elevation from WY2023 (± ft) |
|---|---|---|---|---|---|
| WL-0206 | Trading Post | 6,833.00 | 41.33 | 6,791.67 | +0.09 |
| WL-0207 | Glorieta Battlefield Trail | 7,330.00 | 34.14 | 7,295.86 | −0.01 |
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Report Citation
Authors: Kara Raymond, Andy Hubbard, Cheryl McIntyre
Raymond, K., A. Hubbard, and C. McIntyre. 2024. Climate and Water Monitoring at Casa Grande Ruins National Monument: Water Year 2022. Sonoran Desert Network, National Park Service, Tucson, Arizona.