Springs Monitoring at Fort Bowie National Historic Site: 2024
Bryn Callie, Annika Munson, Cheryl McIntyre, Andy Hubbard
Edited by Tani Hubbard
Please cite this publication as:
Callie, B., A. Munson, C. McIntyre, and A. Hubbard. 2026. Springs Monitoring at Fort Bowie National Historic Site: 2024. Science Report NPS/SR—2026/446. National Park Service, Fort Collins, Colorado. https://doi.org/10.36967/2318584
Abstract
The Sonoran Desert Inventory and Monitoring Network monitors two springs each year at Fort Bowie National Historic Site, Arizona. We assess the condition of the site, measure spring discharge and wetted extent (area that contained water), collect core water quality and water chemistry data, note the wetland plants and invasive plants and animals present, and sample for environmental DNA (eDNA) to inventory springs for rare species, invasive species, and pathogens. Each spring is somewhat unique, and Arizona has not adopted water quality standards that apply across the diversity of springs in the state. Therefore, we continue to collect water quality data at the springs to form a baseline reference of natural variance. We did not detect any of our eDNA target organisms at the springs in 2024. Apache Spring has multiple orifices along a drainage, and the primary orifice is influenced by a springbox, water pipes, and a rock retaining wall. It is an important water source and was a contributing factor in the establishment of Fort Bowie at this location. The spring was wet when we visited in 2024, and the temperature sensor indicated that it was wet all year. A trail leads to this spring and visitors were present during our monitoring visit. For the first time in 2024, we noticed some drying of the riparian vegetation. There were no invasive plants or animals and no obligate or facultative wetland plants at the spring in 2024. Lower Mine Spring is not directly connected to surface water but emerges from a springbox. The park’s allocation of water from this spring is piped downhill where it supports a springbrook and small pool. A social trail from the nearby road leads to the spring. The springbrook had water during our visit, and the temperature sensor showed it was wet all year. We did not find any invasive plants or animals in 2024. Wetland plants included mule-fat and sedges.
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Background
Springs, seeps, and tinajas (discrete 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. At Fort Bowie National Historic Site, 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. We monitor two springs at Fort Bowie National Historic Site each year. 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?).
Climate change is an emerging influence on springs in the American Southwest. Possible changes include increased air temperatures, evaporation rates, and drought intensity; more frequent and extreme rainfall and heat events; and potentially reduced precipitation in the winter and spring. These changes may cause springs to experience reduced flow or even go dry, which may disrupt ecological functions, reduce species diversity, and negatively impact visitor experience.
Springs reporting is by calendar year starting in 2024. Prior to 2024, springs data were summarized by water year (WY), which ran from October through September (e.g., WY2023 started in October 2022 and went through September 2023). In 2024, springs sampling at Fort Bowie National Historic Site occurred on 27 October and 28 October. Water persistence is monitored continuously throughout the year, but in this report we only present 2024 persistence data up to the sampling visit date for each spring.
Methods
Sonoran Desert Network springs monitoring is organized into the four modules described below (see McIntyre et al. 2018 for additional details) and eDNA inventories. All data have undergone certification processes to ensure they have been verified and validated for accuracy, are complete, and are fully documented. Data used in this report are available to park staff on the NPS DataStore and can be provided upon request.
Site Characterization
This module provides context for interpreting change in the other modules. We record GPS locations, draw a site diagram, and describe the spring type (e.g., helocrene, limnocrene, rheocrene, or tinaja) and its associated vegetation in this module. Helocrene springs emerge as low-gradient wetlands, limnocrene springs emerge as pools, and rheocrene springs emerge as flowing streams. This module is completed once every five years or after significant events.
Site Condition
We estimate the level of natural and anthropogenic disturbances and the level of stress on vegetation and soils at the spring on a scale of 1–4, where 1 = undisturbed, 2 = slightly disturbed, 3 = moderately disturbed, and 4 = highly disturbed. Types of natural disturbances can include flooding, drying, fire, wildlife impacts, windthrow of trees and shrubs, beaver activity, and insect infestations. Anthropogenic disturbances can include roads, off-highway vehicle trails, hiking trails, livestock and feral-animal impacts, removal of invasive non-native plants, flow modification, and other evidence of human use of the spring site. We take repeat photographs from the same location and perspective to show the spring and its landscape context. We note the presence of certain obligate wetland plant species (plant species that almost always occur only in wetlands), facultative wetland plant species (plant species that usually occur in wetlands, but also occur in other habitats), and invasive non-native crayfish and American bullfrog (Rana catesbeiana). We also record the density of invasive non-native plants using a qualitative scale (1–5 plants, scattered patches, evenly distributed patches, or a matrix). We complete the site condition module during each springs monitoring visit.
Water Quantity
We measure the persistence of surface water, amount of spring discharge, and wetted extent (area that contained water). To estimate persistence, we analyze the variance of temperature measurements taken by two logging thermometers placed at or near the orifice (spring opening). Because water mediates variation in diurnal temperatures, data from a submerged sensor will show less daily variation than data from an exposed, open-air sensor; this tells us when the spring was wet or dry. Surface discharge is measured with a timed sample of water volume. Wetted extent is a systematic measurement of the physical length (up to 100 m), width, and depth of surface water. It is assessed using a technique for either standing water (e.g., limnocrene and helocrene springs) or flowing water (e.g., rheocrene springs). We complete discharge and wetted extent measurements during each visit when possible. Water persistence measurements are continuous throughout the year.
Water Quality
We measure core water quality and water chemistry parameters. Core water quality parameters include water temperature, pH, specific conductivity (a measure of dissolved compounds and contaminants), dissolved oxygen (how much oxygen is present in the water), and total dissolved solids (an indicator of potentially undesirable compounds). Discrete measurements of these parameters are collected with a multiparameter meter. If the meter fails calibration checks, we do not present data. Water chemistry is assessed by collecting surface water samples and estimating the concentration of major ions with a photometer in the field. These parameters are collected at one or more sampling locations within a spring, but we only present data for the primary sampling location. Each perennial spring is somewhat unique, and Arizona has not adopted water quality standards that would apply across the diversity of springs described here. Ongoing, long-term data collection at each spring will improve our understanding of the natural range in water quality and water chemistry parameters for a given site. We complete the water quality module during each visit when possible. The total number of measurements value we present in the data tables is across all years and may reflect multiple measurements taken in a single year and missing values in other years for a variety of reasons.
eDNA Inventory of Rare and Invasive Species and Pathogens
We inventory rare species, invasive species, and pathogens in perennial springs using environmental DNA (eDNA) techniques. One or more 5-liter water samples are collected and filtered (using a 5 µm self-preserving mesh filter) from each spring using a Smith Root Citizen Science Pump. Samples are preserved in ethanol prior to DNA extraction and analysis by the Goldberg Lab at Washington State University.
Target Organisms for the eDNA Project
The invasive non-native American bullfrog (Rana catesbeiana) that has been previously reported at Fort Bowie National Historic Site and may still be present (Powell et al. 2006).
The pathogen chytrid fungus (Batrachochytrium dendrobatidis), a major threat to amphibians globally that is currently expanding in the American Southwest. Chytrid has not been previously detected at the park.
Ranaviruses, pathogens that can infect amphibians and produce 90–100% mortality in tadpoles and adults and can persist in affected wetlands. Ranaviruses have not been previously detected at the park.
The native Chiricahua leopard frog (Rana chiricahuensis), a federally designated threatened species with a historical range that included Fort Bowie National Historic Site. It was documented on site as recently as 2001 (Powell et al. 2006). Designated critical habitat is located south of the park in the Chiricahua Mountains.
The native lowland leopard frog (Rana yavapaiensis), a species of conservation concern that occurs in the region but has not been observed in the park (Powell et al. 2006).
The native red-spotted toad (Anaxyrus punctatus), a species previously observed at the park by Swann et al. (2001) but not during our extensive biological inventory effort in the early 2000s (Powell et al. 2006).
The native Mexican spadefoot toad (Spea multiplicate), a species previously observed at the park by Swann et al. (2001) but not during our extensive biological inventory effort in the early 2000s (Powell et al. 2006).
The native aquatic northern Mexican garter snake (Thamnophis eques megalops), a federally designated threatened species that has not been previously observed in the park (Powell et al. 2006). Designated critical habitat is found well south of the park at San Bernardino National Wildlife Refuge.
The native tiger salamander (Ambystoma tigrinum), an aquatic predator facing the decline of wetland habitat that has not been previously detected at the park but would be expected to occur there (Powell et al. 2006).
The native jaguar (Panthera onca), a federally designated endangered species that was historically found in Fort Bowie National Historic Site. The park lies within the designated critical habitat for jaguar recovery.
Results
Apache Spring
Apache Spring (Figures 1 and 2) is a rheocrene spring (a spring that emerges into one or more stream channels) in upper Siphon Canyon. Apache Spring consists of multiple orifices occurring along a drainage, with the primary orifice influenced by a springbox and rock retaining wall. These orifices support a springbrook and a variety of riparian trees, shrubs, and herbaceous plants. Apache Spring is an important water source for the area and was a contributing factor in the establishment of Fort Bowie at this location. Apache Spring was visited on 28 October 2024, and it contained water. The spring was last characterized during the April 2022 visit. Spring site characterizations occur every five years.
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Site Condition
Consistent with previous years, we rated Apache Spring as moderately disturbed by hiking trails as the main trail leads directly to the spring and there were visitors at the site. The spring is highly disturbed by flow modification from the rock retaining wall, springbox, and water-diverting pipes (Figure 3). We rated the site as slightly disturbed by wildlife with animal tracks around the springbrook. In past years, we noted evidence of grazing and digging as well as the presence of tracks and scat. Lastly, for the first time in 2024, we rated the spring as slightly disturbed by drying based on the sparseness of riparian vegetation. No other natural or human-caused disturbances were observed at Apache Spring in 2024.
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As in past years, we did not observe any invasive non-native crayfish, American bullfrog (Rana catesbeiana), invasive non-native plants, or obligate/facultative wetland plants at Apache Spring in 2024.
eDNA Inventory of Rare Species, Invasive Species, and Pathogens
One water sample was collected and filtered (5 µm mesh) at Apache Spring during the October 2024 visit. None of our target organisms were detected.
Water Quantity
Sensors are deployed and data are downloaded during our annual visit; the dates of these visits are indicated by black diamonds in the persistence graph (Figure 4). The temperature sensor indicated that Apache Spring was wetted (contained water) for all 302 days (100%) measured up to the October 2024 visit. In prior years, the spring was similarly wetted 100% of the days measured across entire years.
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In 2024, the estimated volumetric discharge was 4.6 ± 1.1 L/min (1.2 ± 0.3 gal/min), which was lower than the range of previous measurements at Apache Spring (Table 1). Wetted extent was evaluated using a method for flowing water. In 2024, the total springbrook length was 48.6 m (159.4 ft). Width and depth averaged 47.1 cm (18.5 in) and 1.2 cm (0.5 in), respectively. All three wetted extent measurements were below the measured ranges from previous sampling years (Table 2).
| Sampling Location |
2024 Mean (Range of Prior Means) |
Prior Years Measured (# of Visits with Measurements) |
|---|---|---|
| 002 | 4.6 ± 1.1 (6.4–16.9) | 2017–2023 (7) |
| Measurement | 2024 Value (Range of Prior Values/Means) |
Prior Years Measured (# of Visits with Measurements) |
|---|---|---|
| Width (cm) | 47.1 ± 45.2 (58.8–93.3) | 2017–2023 (6) |
| Depth (cm) | 1.2 ± 1.0 (1.2–2.2) | 2017–2023 (6) |
| Length (m) | 48.6 (50.4–91.0) | 2017–2023 (6) |
Water Quality
Core water quality (Table 3) and water chemistry (Table 4) data were collected at two sampling locations in Apache Spring in 2024. At the primary sampling location, all core water quality and water chemistry parameters were within the ranges observed in prior years except temperature, which was slightly higher than previously recorded.
| Sampling Location | Parameter | 2024 Value (Range of Prior Values) |
Prior Years Measured (# of Measurements) |
|---|---|---|---|
| 001 | Dissolved oxygen (mg/L) | 6.07 (5.00–6.75) | 2017–2023 (7) |
| 001 | pH | 7.36 (7.28–7.60) | 2017–2023 (7) |
| 001 | Specific conductivity (µS/cm) | 573 (545–624) | 2017–2023 (7) |
| 001 | Temperature (°C) | 18.7 (15.2–18.2) | 2017–2023 (8) |
| 001 | Total dissolved solids (mg/L) | 372 (355–403) | 2017–2023 (7) |
| Sampling Location | Parameter | 2024 Value (Range of Prior Values) |
Prior Years Measured (# of Measurements) |
|---|---|---|---|
| 001 | Alkalinity (CaCO3) | 245 (35–275) | 2017–2023 (7) |
| 001 | Calcium (Ca) | 80 (56–105) | 2017–2023 (7) |
| 001 | Chloride (Cl) | 16 (0–52) | 2017–2023 (7) |
| 001 | Magnesium (Mg) | 5 (5–19) | 2017–2023 (7) |
| 001 | Potassium (K) | 1.2 (0.5–2.3) | 2017–2023 (7) |
| 001 | Sulphate (SO4) | 46 (29–50) | 2017–2023 (7) |
Lower Mine Spring
Lower Mine Spring (Figures 5 and 6) is a cave spring that is not directly connected to surface water but emerges from a springbox where its flow is divided between Fort Bowie National Historic Site and an adjacent landowner with water rights. The park’s water allocation is piped 10 m downhill from the springbox where it supports a springbrook and a small, shallow pool. Lower Mine Spring supports a dense canopy of shrubs and herbaceous vegetation and was last characterized in 2022. Spring systems are recharacterized every five years. The 2024 visit to Lower Mine Spring occurred on 27 October, and the spring contained water.
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Site Condition
Similar to our 2022 and 2023 site visits, we rated Lower Mine Spring as slightly disturbed by roads and hiking trails; there is a paved road located approximately 10–20 m from the spring and a social trail leading from the road to the site (Figure 7). The site is highly disturbed by flow modification because of the springbox and piping. In 2024, there was slight disturbance by wildlife with deer tracks along the springbrook; in past years, we observed evidence of javelina and deer use at the site, including scat, tracks, and wallows. No other natural or human-caused disturbances were observed at Lower Mine Spring in 2024.
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As in past years, we did not observe invasive non-native crayfish or American bullfrog (Rana catesbeiana) at Lower Mine Spring in 2024, and we did not observe any non-native invasive plants. Consistent with previous years, we observed two species of obligate or facultative wetland plants: mule-fat (Baccharis salicifolia, a facultative wetland shrub species), and sedge (Carex sp., an obligate wetland rush plant).
eDNA Inventory of Rare Species, Invasive Species, and Pathogens
One water sample was collected and filtered (5 µm mesh) at Lower Mine Spring during the October 2024 visit. None of our target organisms were detected.
Water Quantity
Sensors are deployed and data are downloaded during our annual visit; the dates of these visits are indicated by black diamonds in the persistence graph (Figure 8). The temperature sensor indicated that Lower Mine Spring was wetted (contained water) for all 301 days (100%) measured up to the 2024 visit. In prior years, the spring was similarly wetted 100% of the days measured across entire years.
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In 2024, the estimated volumetric discharge of Lower Mine Spring was 6.7 ± 0.9 L/min (1.8 ± 0.21 gal/min), which was lower than all previous measurements (Table 5). Wetted extent was evaluated using a method for flowing water. In 2024, the total springbrook length was 22.5 m (73.8 ft). In past years, brook lengths ranged from 12.1 to 52.1 m (39.7 to 171.0 ft). In 2024, width and depth along the springbrook averaged 66.6 cm (26.2 in) and 2.2 cm (0.9 in), respectively. All three wetted extent measurements were within the ranges of previous values (Table 6).
| Sampling Location |
2024 Mean (Range of Prior Means) |
Prior Years Measured (# of Visits with Measurements) |
|---|---|---|
| 002 | 6.7 ± 0.9 (8.5–16.5) | 2017–2022 (5) |
| Measurement | 2024 Value (Range of Prior Values/Means) |
Prior Years Measured (# of Visits with Measurements) |
|---|---|---|
| Width (cm) | 66.6 ± 35.9 (38.0–85.8) | 2017–2022 (5) |
| Depth (cm) | 2.2 ± 2.2 (0.7–2.9) | 2017–2022 (5) |
| Length (m) | 22.5 (12.1–52.1) | 2017–2022 (5) |
Water Quality
Core water quality (Table 7) and water chemistry (Table 8) data were collected at the primary sampling location in Lower Mine Spring in 2024. Dissolved oxygen and total dissolved solids values were slightly higher than the ranges recorded in previous years. Specific conductivity, temperature, and pH levels were all found to be within the ranges previously recorded, with specific conductivity and temperature being at the higher ends of their respective ranges. Calcium and chloride levels were within the ranges recorded in previous years. Alkalinity, magnesium, and potassium levels were below and sulphate levels were above previous ranges.
| Sampling Location | Parameter | 2024 Value (Range of Prior Values) |
Prior Years Measured (# of Measurements) |
|---|---|---|---|
| 001 | Dissolved oxygen (mg/L) | 6.56 (5.38–6.35) | 2017–2023 (9) |
| 001 | pH | 7.23 (7.20–7.40) | 2017–2023 (9) |
| 001 | Specific conductivity (µS/cm) | 555.0 (533.4–557.0) | 2017–2023 (9) |
| 001 | Temperature (°C) | 19.4 (17.8–19.4) | 2017–2023 (10) |
| 001 | Total dissolved solids (mg/L) | 361.0 (346.4–360.0) | 2017–2023 (9) |
| Sampling Location | Parameter | 2024 Value (Range of Prior Values) |
Prior Years Measured (# of Measurements) |
|---|---|---|---|
| 001 | Alkalinity (CaCO3) | 215 (235–260) | 2017–2023 (7) |
| 001 | Calcium (Ca) | 74 (b.d.l.–95) | 2017–2023 (7) |
| 001 | Chloride (Cl) | 18 (1–39) | 2017–2023 (7) |
| 001 | Magnesium (Mg) | 8 (9–22) | 2017–2023 (7) |
| 001 | Potassium (K) | 2.1 (2.2–3.2) | 2017–2023 (7) |
| 001 | Sulphate (SO4) | 54 (24–51) | 2017–2023 (7) |
Past Reports
Previous annual reports can be found at the following links:
Literature Cited
McIntyre, C., K. Gallo, E. Gwilliam, J.A. Hubbard, J. Christian, K. Bonebrake, G. Goodrum, M. Podolinsky, L. Palacios, et al. 2018. Springs, seeps, and tinajas monitoring protocol: Chihuahuan and Sonoran Desert Networks. Natural Resource Report. NPS/CHDN/NRR—2018/1796. National Park Service. Fort Collins, Colorado. https://irma.nps.gov/DataStore/Reference/Profile/2257245
Powell, B.F., C.A. Schmidt, W.L. Halvorson, and P. Anning. 2006. Vascular plant and vertebrate inventory of Fort Bowie National Historic Site. U.S. Geological Survey Open-File Report 2005-1167. USGS Southwest Biological Science Center, Sonoran Desert Research Station, University of Arizona, Tucson, Arizona. https://irma.nps.gov/DataStore/Reference/Profile/2174395
Swann, D.E., M.J. Goode, and C.R. Schwalbe. 2001. Inventory and recommendations for long-term monitoring of reptiles and amphibians at Fort Bowie National Historic Site, Arizona. Final Report to National Park Service Southern Arizona Group Office. School of Renewable Natural Resources, University of Arizona and USGS Sonoran Desert Field Station, Tucson, Arizona.
Author Information
Bryn Callie 1
Annika Munson 1
Cheryl McIntyre
1 
https://orcid.org/0000-0001-7554-7586
Andy Hubbard 1 https://orcid.org/0000-0002-4223-7730
Edited by Tani Hubbard 2
https://orcid.org/0009-0009-8777-4773
1
Sonoran Desert Inventory and Monitoring Network
12661 E. Broadway Blvd.
Tucson, Arizona
2
Northern Rockies Conservation Cooperative and National Park
Service
12661 E. Broadway Blvd.
Tucson, Arizona
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