Article

Climate and Water Monitoring at Gila Cliff Dwellings National Monument: Water Year 2022

A streaking orange sunset over silhouetted mountains.
Gila Wilderness

NPS/E. SCHNAUBELT

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 Gila Cliff Dwellings National Monument (Figure 1), Sonoran Desert 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 problems, allowing managers to mitigate them before they become worse. At Gila Cliff Dwellings National Monument, we monitor climate and springs, among other vital signs.

Surface-water conditions are closely related to climate conditions. Because they are better understood together, we report on climate in conjunction with water resources. 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., WY2022 runs from October 2021 through September 2022).

This article reports on results of climate and water monitoring done at Gila Cliff Dwellings National Monument in WY2022.

Map showing the park, situated along the Gila River, with the weather station about 3.5 miles downstream from the park boundary.
Figure 1. Monitored weather station near Gila Cliff Dwellings National Monument.

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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

Gila Cliff Dwellings National Monument has had a nearby National Oceanic and Atmospheric Administration (NOAA) Cooperative Observer Program (COOP) weather station since 1957 (Station 293530; see Figure 1). This station provides a reliable, long-term climate dataset used for analyses in this climate and water report. Data from this station are accessible through Climate Analyzer.

Results for Water Year 2022

Precipitation

Annual precipitation at Gila Cliff Dwellings National Monument in WY2022 was 18.35″ (46.6 cm; Figure 2), 3.18″ (8.1 cm) more than the 1991–2020 annual average. Monthly precipitation was below average for the entire year, except during the monsoon season. Early monsoon rains totaled 4.11″ (June), over six times the 1991–2020 June average. July and August received one and a half and twice their average rainfall, respectively. Extreme daily rainfall events (> 1″ or 2.54 cm) occurred on 4 days, twice the average annual frequency of 1.9 days. Extreme rainfall events occurred on 27 June 2022 (1.53″ or 3.8 cm); 10 July 2022 (1.41″ or 3.6 cm); 20 August 2022 (2.05″ or 5.2 cm); and 27 August 2022 (1.05″ or 2.7 cm).

Air Temperature

Mean annual maximum and minimum temperatures in WY2022 were similar to the 1991–2020 annual averages. The mean annual maximum air temperature at Gila Cliff Dwellings National Monument was 74.4°F (23.6°C), 0.9°F (0.5°C) warmer than the 1991–2020 average. The mean annual minimum air temperature in WY2022 was 34.1°F (1.2°C), 0.7°F (0.4°C) warmer than average. Mean monthly maximum and minimum temperatures in WY2022 varied up to 6.0°F (3.3°C) relative to the 1991–2020 monthly average temperatures (Figure 2). On 20 days in WY2022, we recorded extremely hot temperatures (> 93°F, 33.9°C), the same as the 1991–2020 average annual frequency (20.3 days). Extremely cold temperatures (< 12°F, −11.1°C) occurred on 23 days, more than the average annual frequency of 14.7 days.

Climogram plotting monthly precipitation of 2022 compared to the 1991-2020 average, as well as the monthly maximum and minimum temperatures of 2022 compared to the past average.
Figure 2. Climogram showing monthly precipitation and mean maximum and minimum temperature, water year 2022 and the 1991–2020 averages at Gila Cliff Dwellings National Monument. Data source: climateanalyzer.org.

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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 Gila Cliff Dwellings National Monument indicates that WY2022 was wetter than the 1991–2022 annual 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 the reconnaissance drought index for all but two years since 1991, showing relatively low values for recent years.
Figure 3. Reconnaissance drought index for Gila Cliff Dwellings National Monument, water years 1991–2022.  Data source: climateanalyzer.org. Drought index calculations are relative to the time period selected (1990–2022). Choosing a different set of start/end points may produce different results.

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Springs

Background

Springs, seeps, and tinajas (pools in a rock basin or impoundments in bedrock) are small, relatively rare biodiversity hotspots in arid lands. They are the primary connection between groundwater and surface water and are important water sources for plants and animals. For springs, the most important questions we ask are about persistence (How long was there water in the spring?) and water quantity (How much water was in the spring?).

A small pool and stream in a rocky channel.
Figure 4. Cliff Dweller Canyon Spring at Gila Cliff Dwellings National Monument, June 2022.

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Recent Findings at Cliff Dweller Canyon Spring

Cliff Dweller Canyon Spring is a rheochrene spring (emerges as a flowing stream) emanating from the base of a large overhanging cliff (Figure 4). When characterized on 22 June 2022, the spring was comprised of a series of small (15–30 cm diameter) pools in the streambed with cold, clear water supporting abundant aquatic insects. Lower Cliff Dweller Canyon Spring (a spring that is not monitored regularly but also emerges from the rhyolite cliff-face) also contained water. It supported a springbrook of more than 0.5 km, though the springbrook did not extend to the Gila River (West Fork) during that dry season. We suspect that Cliff Dweller Canyon and Lower Cliff Dweller Canyon springs are linked into one spring complex, although, unlike Cliff Dweller Spring, Lower Cliff Dweller Spring is often seasonally dry (per observations by monument staff and volunteers).

Site Condition

As in past years, we did not observe disturbance from natural or anthropogenic sources at Cliff Dweller Canyon Spring. We also did not detect crayfish or bullfrogs (non-native, invasive aquatic animals), nor did we observe any non-native plants. The obligate wetland forb monkeyflower (Mimulus sp.) was first observed at Cliff Dweller Spring in 2022, growing in dense linear patches along the springbrook.

Four water samples were collected and filtered (0.45 µm mesh) from the springbrook and pools at Cliff Dweller Canyon Spring on 22 June 2022 to analyze eDNA. None of our target organisms were detected. Data collection for this eDNA inventory continues at this site, and additional information will be provided in a future, more detailed report.

Water Quantity

The WY2022 visit occurred on 22 June 2022, and the spring contained water. Temperature sensors indicated that Cliff Dweller Canyon Spring was ‘wetted’ for all 265 days (100% of days) measured up to the WY2022 visit (Figure 5). In prior water years, the spring was wetted 100% of the days measured.

Water persistence graph for Cliff Dweller Canyon Spring showing the spring has been wet since October 2017.
Figure 5. Water persistence in Cliff Dweller Canyon Spring, Gila Cliff Dwellings National Monument.

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Discharge was estimated at 7.6 (± 0.3) L/min (2 ± 0.1 gal/min) in WY2022. This was on the lower end of the range of previous discharge measurements at Cliff Dweller Canyon Spring (Table 1).

Wetted extent was evaluated using a method for flowing water. The total brook length was 200–500 m (656–1,640 ft). Width and depth averaged 55.1 cm (21.7 in), and 2.5 cm (1 in), respectively, within the first 100 m—on the lower end of the range observed in past years (Table 2).

Water Quality

Core water quality (Table 3) and water chemistry (Table 4) data were collected at the primary sampling location. The values were generally within the range recorded in prior years, with a few notable exceptions: (1) chloride was almost triple the amount previously observed (Table 4), although still relatively low as compared to many other springs in the region (e.g., Dripping Springs at Organ Pipe Cactus National Monument), and (2) water temperature was about 1.5°C warmer than previously observed (Table 3). Both increased water temperature and chloride may be due to evaporation and reduced water quantity as compared with previous years.

Cliff Dweller Canyon Spring Data Tables

A series of pools and lush green vegetation in a canyon bottom with a measuring tape and clipboard near the largest pool.
Figure 6. Hubbard’s Bog at Gila Cliff Dwellings National Monument, June 2022.

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Recent Findings at Hubbard's Bog

Hubbard’s Bog is a rheochrene spring (emerges as a flowing stream) located in a narrow, north-facing canyon on the south side of the Gila River (West Fork). When characterized during the 23 June 2022 visit, the orifice occurred as a seep at the base of a bedrock outcrop, supporting small willow trees and other riparian plants (Figure 6). About 14 m downstream of the orifice, the first of four open pools emerged, with shallow mucky surface water and thick sedges connecting the pools. The top two pools were shallow and mucky, and contained dense grasses, sedges, and small willow and locust trees. The bottom two pools were bathtub sized, with lots of open water encircled by riparian plants. Aquatic insects were abundant throughout the site. As with Cliff Dweller Canyon Spring, a series of seeps and orifices lower in the canyon suggest a complex of springs, though the lower section appears to be seasonally dry. Descriptions and other characteristics of springs are updated every five years.

Site Condition

Consistent with past years (2017–2021), we rated Hubbard’s Bog as “slightly disturbed” in WY2022 due to the continuing impacts of the 2011 Miller Fire on adjacent tree canopies. Also as in the past, the site was rated “undisturbed” for other natural and human-caused disturbances. We did not observe crayfish or bullfrogs (non-native, invasive aquatic animals), nor did we detect any non-native plants at Hubbard’s Bog in WY2022.

We observed several obligate wetland plant genera that have been present in past years: rushes (Juncaceae sp.), spikerush (Eleocharis sp.), monkeyflower (Mimulus sp.), and willow trees (Salix sp.).

Four water samples were collected and filtered (0.45 µm mesh) from the springbrook and pools at Hubbard’s Bog Spring on 23 June 2022 for eDNA analysis. None of our target organisms were detected. Data collection for this eDNA inventory continues at this site, and additional information will be provided in a future, more detailed report.

Water Quantity

Temperature sensors indicated that Hubbard’s Bog was "wetted" (contained water) for 266 of 266 days (100% of days) measured up to the WY2022 visit (Figure 7). In prior water years, the spring was also wetted 100% of the days measured.

Water persistence graph for Hubbard’s Bog showing the spring being wet in all data collected.
Figure 7. Water persistence in Hubbard’s Bog, Gila Cliff Dwellings National Monument.

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As in past years, discharge could not be measured in WY2022 as there was no discernable surface flow. Wetted extent was evaluated using a method for flowing water at Hubbard’s Bog in WY2022. The total brook length was 44 m (144 ft). Width and depth averaged 34.9 cm (13.7 in), and 5.6 cm (2.2 in), respectively, within the first 100 m—comparable with measures in past years (2017–2020; Table 5).

Water Quality

Core water quality and water chemistry data were collected at the primary sampling location, although the latter had to be collected with a syringe due to the shallow nature of the pool, which may have influenced those results. We will likely move the primary sampling location to one of the larger pools in future years to avoid this issue. Water-quality values were comparable with past years (Table 6), although specific conductivity and total dissolved solids were lower than previously observed (2017–2021). Perhaps due to collecting water chemistry samples with the syringe, the water chemistry values of Hubbard’s Bog were considerably different than in prior years, with alkalinity and calcium substantially lower and potassium and sulfate substantially higher than observed in past years (Table 7). As in the past, chloride and magnesium remained below the detection level of the instrument.

Hubbard's Bog Data Tables

Past Findings

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    Gila Cliff Dwellings National Monument

    Last updated: May 30, 2024