Article

Climate and Groundwater Monitoring at Coronado National Memorial: Water Year 2024

Dry grasses, cactus, and a few live and dead trees on a desert hillside above a desert valley with mountains in the distance.
Coronado National Memorial

NPS

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 Coronado National Memorial (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 Coronado National Memorial, 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 Coronado National Memorial in WY2024.

Map of Coronado National Memorial showing one weather station and two groundwater wells near headquarters and four groundwater wells on the southeastern part of the park.
Figure 1. Monitored weather station and groundwater wells at Coronado National Memorial.

NPS

Climate and Weather

There is often confusion over the terms “weather” and “climate.” Weather describes short-term meteorological conditions (e.g., it’s currently raining or snowing, it’s a hot or frigid day), and 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 Cooperative Observer Program (NOAA COOP) weather station (Coronado Natl. Mon. HQ #022140) has been operational at Coronado National Memorial since 1960 (Figure 1). This station provides a reliable, long-term climate dataset for analyses in this climate and water report. Data from this station are accessible through Climate Analyzer.

Sunlight peeking through dark storm clouds over a barren mountain surrounded by desert hills covered in dry grasses and green shrubs.
Montezuma Peak at Coronado National Memorial

NPS/KATY HOOPER

Results

Precipitation

Highlight: Precipitation was lower than normal as a strong start to the monsoon season rapidly dwindled.

Annual precipitation at Coronado National Memorial in WY2024 was 19.47″ (49.5 cm), 1.28″ (3.3 cm) less than the 1991–2020 annual average. Monthly precipitation totals for October–December in WY2024 were drier than the 1991–2020 averages (Figure 2). January–April monthly precipitation totals were wetter than or similar to the averages. May was completely dry. The monsoon started strong in June with nearly three times its average rainfall and then tapered off relative to the monthly averages through September, which received a tenth of its average. Extreme daily rainfall events (≥ 1.00″; 2.54 cm) occurred on 3 days, less than the average annual frequency of 4.5 days. Extreme rainfall events occurred on 01 April 2024 (1.02″; 2.6 cm), 16 July 2024 (1.04″; 2.6 cm), and 30 July 2024 (1.08″; 2.7 cm).

Air Temperature

Highlight: Warmer than average temperatures with more extremely hot summer days.

The mean annual maximum temperature at Coronado National Memorial in WY2024 was 76.2°F (24.6°C), 1.2°F (0.7°C) above the 1991–2020 average. The mean annual minimum temperature in WY2024 was 49.5°F (9.7°C), 2.0°F (1.1°C) above the 1991–2020 average. Mean monthly maximum and minimum temperatures in WY2024 differed by as much as 5.5°F (3.1°C; see December as an example) relative to the 1991–2020 monthly averages (Figure 2). Mean monthly maximum temperatures were above the averages in all months except January, March, and April. Mean monthly minimum temperatures were above average in every month except March. Extremely hot temperatures (≥ 94.0°F; 34.4°C) occurred on 33 days in WY2024, nine more than the average frequency of 23.5 days. Extremely cold temperatures (≤ 26°F; −3.3°C) occurred on 10 days, nine less than the average frequency of 18.5 days.

Climogram: WY2024 max and min temperature averages were higher than for 1991–2020 in most months. Precipitation totals in January, February, April, and June are greater than averages, similar to average in March and July and less than average other months
Figure 2. Climogram showing monthly precipitation and mean maximum and minimum air temperatures in water year (WY) 2024 and the 1991–2020 averages at Coronado National Memorial. Data source: climateanalyzer.org.

NPS

Drought

Highlight: Drought conditions continued.

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 Coronado National Memorial indicates WY2024 was drier than the 1991–2024 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.

Bar graph showing water years 2023 and 2024 were drier than average.
Figure 3. Reconnaissance drought index at Coronado National Memorial, water years (WY) 1991–2024. Drought index calculations are relative to the time period selected (1990–2024). Choosing a different set of start/end points may produce different results. N/A = insufficient data to generate reliable estimates. Data source: climateanalyzer.org.

NPS

Very tall agave flowering stalks sticking out from a landscape of thick yellow flowers in front of desert mountains.
Coronado National Memorial

NPS

Groundwater 

Groundwater is one of the most critical natural resources of the American Southwest. It provides drinking water, irrigates crops, and sustains rivers, streams, and springs throughout the region.

Methods

At Coronado National Memorial, groundwater is monitored using six wells (Figure 1). The Sonoran Desert Network currently monitors five wells: two using automated methods (ACA-3 and Border) and three using manual methods quarterly (WSW-2, Headquarters, and X-2). The US Geological Survey (USGS) monitors the sixth well, Baumkirchner #3, using automated methods. USGS data for Baumkirchner #3 is available at USGS 312044110141901.

Results

Highlight: Generally, there were slight declines in groundwater depth with variance between wells.

Groundwater monitoring results for WY2024 are summarized in Table 1. Well water levels are shown in Figures 4, 5, and 6 and grouped by depth to water rather than geographic proximity or wellhead elevation.

  • Mean water level elevations at the Headquarters, Baumkirchner #3, X2, WSW-2, and Border wells in WY2024 were lower than in WY2023 (Table 1; Figures 4 and 5). Water elevation in ACA3 in WY2024 was slightly higher than in the previous water year.

  • Water level in the Headquarters well is highly variable. Lower water levels in WY2024 are likely a response to fewer and smaller runoff events in Montezuma Canyon Wash (Figure 4).

  • Water level in Baumkirchner #3 is relatively stable but exhibits seasonal fluctuations and appears to be slightly decreasing since WY2010 (Figure 4).

  • Water level in X2 well has exhibited low variability over the monitoring record, likely because of the alignment of the aquifer’s geologic formation. However, the four manual measurements in WY2024 were the lowest of the monitoring record (Figure 5).

  • WSW-2 is the park’s water supply, and pumping can cause nearly 120 ft of drawdown. WSW-2 static water level has no apparent upward or downward trend (Figure 5).

  • Fluctuations in the ACA3 water level appear to follow those in WSW-2. This may indicate that both aquifers are responding to the same recharge events, although the response at ACA3 is delayed. While the mean water elevation in WY2024 was higher than the previous year, there does appear to be an overall decreasing trend. (Figure 5).

  • Water level in the Border well has demonstrated a consistent decline throughout the recent monitoring period. Results in WY2024 are the lowest in the monitoring record. (Figure 6).

Line graph showing water levels for one well exhibit a lot of variability, and the other well shows more stable and less variable water levels.
Figure 4. Depth to water in feet below ground surface (ft bgs) at Headquarters and Baumkirchner #3 groundwater monitoring wells at Coronado National Memorial, water years (WY) 1998–2024. White diamonds indicate the well was dry.

NPS

Line graph showing one well exhibits stable water levels, and the other two wells show more variability.
Figure 5. Depth to water in feet below ground surface (ft bgs) at X2, WSW-2, and ACA3 groundwater monitoring wells at Coronado National Memorial, water years (WY) 1998–2024. White diamonds indicate manual measurements collected when the well was being pumped or had recently been pumped.

NPS

Graph showing declining water levels in the monitored well over the entire monitoring period.
Figure 6. Depth to water in feet below ground surface (ft bgs) at the Border groundwater monitoring well at Coronado National Memorial, water years (WY) 2014–2024.

NPS

Report Citation

Author: Kara Raymond

Raymond, K. 2025. Climate and Groundwater Monitoring at Coronado National Memorial: Water Year 2024. Sonoran Desert Network, National Park Service, Tucson, Arizona.

Tags

Coronado National Memorial

Last updated: November 25, 2025