Springs Monitoring at Chiricahua National Monument: 2024

Elora Ormand, Elizabeth Schnaubelt, Cheryl McIntyre, Andy Hubbard

Edited by Tani Hubbard

Please cite this publication as:

Ormand, E., E. Schnaubelt, C. McIntyre, and A. Hubbard. 2026. Springs Monitoring at Chiricahua National Monument: 2024. Science Report NPS/SR—2026/445. National Park Service, Fort Collins, Colorado. https://doi.org/10.36967/2318578

Abstract

The Sonoran Desert Inventory and Monitoring Network monitors three springs each year at Chiricahua National Monument, Arizona. We assess the condition of the spring, 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 any of the three springs in 2024. Water was present at Garfield Spring in 2024, but the channel was not visibly flowing when we visited, so we were unable to measure discharge. We noted drying at the spring for the first time since monitoring began, but the temperature sensor indicated that the spring never completely dried up during the year. Sedges were growing at the site and no invasive plants or animals were detected. Shake Spring is modified by a springbox and iron pipe installed to direct the flow of water. The temperature sensor showed the spring had water all year. The spring is close to hiking trails and a main park road. A few common mullein plants (invasive species) are growing in the drainage and have been observed in other years. Wetland plants at the site included horsetail, monkeyflower, sedges, sycamore, and willow. Silver Spur Spring begins in a stagnant pool and continues with intermittent water in a series of large pools. In 2024, we detected evidence of a past fire around the spring, but riparian vegetation was unaffected. There was trash and vegetation trampling in and around the spring. The temperature sensor showed the spring had water all year. We first detected common mullein in 2022 and several of these plants were present in 2024. Wetland plants included horsetail, sedges, and sycamore.

A forested hillside in the mountains filled with hoodoos, tall spires of eroded rock that look like towers of stacked rocks.
Chiricahua National Monument, Arizona.

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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 Chiricahua National Monument, 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 three springs at Chiricahua National Monument 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 Chiricahua National Monument occurred on 26 October and 27 October. Water persistence is monitored continuously throughout the year using in-situ sensors, 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 Species, 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 is suspected but not confirmed to currently occur within Chiricahua National Monument (Powell et al. 2008).

  • The pathogen chytrid fungus (Batrachochytrium dendrobatidis), a major threat to amphibians globally that is currently expanding in the American Southwest but has not been previously detected in 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 the park (Powell et al. 2008). Designated critical habitat is located east of the park.

  • The native lowland leopard frog (Rana yavapaiensis), a species of conservation concern that occurs in the region but has not been observed within the park (Powell et al. 2008).

  • The native red-spotted toad (Anaxyrus punctatus), a species previously observed at the monument in the late 1990s (Prival and Schwalbe 2000) but not detected by our systematic biological inventory (Powell et al. 2008).

  • The native Mexican spadefoot toad (Spea multiplicate), a species previously observed at the monument (Powell et al. 2008).

  • The native aquatic northern Mexican garter snake (Thamnophis eques megalops), a federally designated threatened species that has previously been observed within the park (Powell et al. 2008). Designated critical habitat is found south of the Chiricahua Mountains.

  • The native jaguar (Panthera onca), a federally designated endangered species that was historically found within the park. The park lies within the designated critical habitat for jaguar recovery.

  • The native tiger salamander (Ambystoma tigrinum), an aquatic predator facing the decline of wetland habitat that has historically been detected within the park.

Results

Garfield Spring

Garfield Spring (Figures 1 and 2) is a rheocrene spring (a spring that emerges into one or more stream channels). The spring forms a small, rocky pool beneath an overhanging rock, stabilized by roots. The water is clear but shallow, with a silty bottom. Grassy plants surround the pool. The 2024 visit occurred on 26 October 2024, and the spring contained water. The channel had water but was not visibly flowing.

Figure 1. A small pool of water surrounded by long, green grass, thick roots, and rocks.
Figure 1. Garfield Spring at Chiricahua National Monument, October 2024. Water emerges from a small rocky pool at the spring’s orifice.

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Figure 2. A forest of evergreen pine, juniper, and oak trees surround the spring site. No water is visible, but riparian bunch grasses are clustered nearby.
Figure 2. Garfield Spring at Chiricahua National Monument, October 2024.

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Site Condition

As in past years, Garfield Spring was slightly disturbed by hiking trails, with a social/game trail leading to the water. For the first time, we rated the spring as slightly disturbed by drying because there was no flowing water and there were few wetland plants present (Figure 3). We found bear and coyote scat at the spring and saw deer when we visited the site. No other natural or human-caused disturbances were observed at Garfield Spring in 2024.

Figure 3. In one image, a faint social trail is visible through trees leading to the spring, and in the other image the spring depression looks mostly dry, with damp dirt and sticks filling in the depression.
Figure 3. Examples of disturbance at Garfield Spring in 2024. Left: social/game trail at site. Right: orifice with minimal water that does not appear to be flowing.

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As in past years, we did not observe invasive non-native crayfish or American bullfrog (Rana catesbeiana), or any invasive non-native plants at Garfield Spring in 2024. We observed one obligate/facultative wetland plant species: sedge (Carex sp., previously observed in 2018–2023).

eDNA Inventory of Rare Species, Invasive Species, and Pathogens

One water sample was collected and filtered from Garfield Spring on 26 October 2024. None of our target organisms, including chytrid fungus and ranavirus, were detected on the filter.

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 Garfield Spring was wetted (contained water) for 300 of 300 days (100%) measured up to the 2024 visit. In prior years, the spring was wetted 99.5–100% of the days measured across entire years.

Figure 4. Area chart showing the spring contained water from January 2017 through the 2024 visit date, except for a very short periods in 2017 and 2020 when data were missing.
Figure 4. Water persistence through 26 October 2024 in Garfield Spring, Chiricahua National Monument. White areas indicate dates before sensors were first deployed or after the 2024 visit. Black diamonds indicate sensor deployment dates.

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Discharge was not measured in 2024 because of a lack of flowing surface water at the site. Past data are summarized in Table 1. Wetted extent was evaluated using a method for flowing water. The total springbrook length was 28.8 m (94.5 ft). In the past, springbrook lengths ranged from 24.9–37.5 m (81.7–123.0 ft). In 2024, width and depth of the springbrook averaged 27.8 cm (10.9 in) and 0.7 cm (0.3 in), respectively. In 2024, the average width was slightly narrower than in prior years, and the average depth and total length were within the range of previous measurements (Table 2).

Table 1. Discharge data (L/min; mean ± SD) for Garfield Spring in 2024 and a range of means from prior years. c.n.s. = could not sample.
Sampling
Location		 2024 Mean
(Range of Prior Means)		 Prior Years Measured
(# of Visits with Measurements)
002 c.n.s. (0.2–0.6) 2017–2022 (5)

Table 2. Length and average (± SD) width and depth of Garfield Spring (measured within the first 100 m of springbrook length) in 2024 and ranges of length values and width and depth means from prior years.
Measurement 2024 Value
(Range of Prior Values/Means)		 Prior Years Measured
(# of Visits with Measurements)
Width (cm) 27.8 ± 16.0 (28.1–47.9) 2017–2023 (6)
Depth (cm) 0.7 ± 0.5 (0.3–0.9) 2017–2023 (6)
Length (m) 28.8 (24.9–37.5) 2017–2023 (6)

Water Quality

Core water quality (Table 3) and water chemistry (Table 4) data were collected at the primary sampling location. The values for dissolved oxygen, pH, and temperature were within the ranges recorded in prior years, while specific conductivity and total dissolved solids were both greater in 2024 than in previous years. All water chemistry values were within the ranges recorded in previous years, except sulphate, which was higher in 2024.

Table 3. Core water quality data for Garfield Spring in 2024 and a range of values from prior years.
Sampling Location Parameter 2024 Value
(Range of Prior Values)		 Prior Years Measured
(# of Measurements)
001 Dissolved oxygen (mg/L) 5.10 (2.67–5.51) 2017–2023 (7)
001 pH 7.09 (6.82–7.88) 2017–2023 (7)
001 Specific conductivity (µS/cm) 192.3 (182.2–188.1) 2017–2023 (7)
001 Temperature (°C) 15.4 (11.9–15.9) 2017–2023 (8)
001 Total dissolved solids (mg/L) 125.0 (118.0–122.2) 2017–2023 (7)

Table 4. Water chemistry data (mg/L) for Garfield Spring in 2024 and a range of values from prior years. b.d.l. = below detection limit.
Sampling Location Parameter 2024 Value
(Range of Prior Values)		 Prior Years Measured
(# of Measurements)
001 Alkalinity (CaCO3) 70 (45–80) 2017–2023 (7)
001 Calcium (Ca) 16 (12–20) 2017–2023 (7)
001 Chloride (Cl) 10 (2–22) 2017–2023 (7)
001 Magnesium (Mg) 1 (b.d.l.–11) 2017–2023 (7)
001 Potassium (K) 2.2 (1.4–2.4) 2017–2023 (7)
001 Sulphate (SO4) 5 (0–4) 2017–2023 (7)

Shake Spring

Shake Spring (Figures 5 and 6) is a rheocrene spring (a spring that emerges into one or more stream channels) that originates about 20 m upstream of a concrete springbox as a shallow pool at the base of a large boulder. The water meanders around boulders and over a bed of leaves, detritus, and algae. Near the springbox, two large rocks form a bottleneck that channels water into a larger pool created by a small man-made dam. The sides of the channel range from 30-degree slopes of soil and rock to steep bedrock walls. The 2024 visit occurred on 27 October, and the spring contained water.

Figure 5. A tall concrete spring box sits inside a narrow springbrook surrounded by large boulders. Narrow pools of water are shown at the base of the boulders and on either side of the stream channel.
Figure 5. Shake Spring at Chiricahua National Monument, October 2024. An old spring box modifies its flow. The main orifice can be seen in the background as a shallow pool of clear water surrounded by large boulders.

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Figure 6. A couple of water pools in a very rocky channel lined by some bunches of green grass and trees. A scientist is sitting in the channel collecting data.
Figure 6. Shake Spring at Chiricahua National Monument, October 2024. The springbrook forms a series of connected pools that flow through a rocky channel.

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Site Condition

The spring was slightly disturbed by wildlife with deer tracks surrounding the spring. We also rated the site as slightly disturbed by windthrow because several trees and branches had fallen around the springbrook—this is usual for the area, and this spring has even been rated moderately disturbed by windthrow in the past. The spring was moderately disturbed by flow modification because there is a springbox and an iron pipe installed to direct flow (Figure 7). A main park road passes by about 15 m from the spring. No other natural or human-caused disturbances were observed at Shake Spring in 2024.

Figure 7. A plant with large green leaves arranged like petals of a flower growing low to the ground in one picture and a paved road along a thick forest with a rectangular concrete structure set not far into the forest.
Figure 7. Examples of disturbance at Shake Spring in 2024. Left: invasive mullein (Verbascum thapsus). Right: paved road about 15 m from spring, and the concrete springbox is visible on the right side of the image.

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As in past years, we did not observe invasive non-native crayfish or American bullfrog (Rana catesbeiana) at Shake Spring in 2024. We observed one invasive non-native plant species at the spring: 1–5 common mullein plants (Verbascum thapsus, 1–5 plants previously observed in 2019–2022).

We observed five species of obligate/facultative wetland plants at Shake Spring in 2024: horsetail (Equisetum sp., a forb previously observed in 2017–2023); monkeyflower (Mimulus sp., a forb previously observed in 2017–2022); at least one species of sedge (Carex sp., previously observed in 2018–2023); sycamore (Platanus sp., a tree previously observed in 2017–2023); and willow (Salix sp., a tree/shrub previously observed in 2018–2023).

eDNA Inventory of Rare Species, Invasive Species, and Pathogens

One water sample was collected and filtered from Shake Spring on 27 October 2024. None of our target organisms, including chytrid fungus and ranavirus, were detected on the filter.

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 Shake Spring was wetted (contained water) for 301 of 301 days (100%) measured up to the 2024 visit. In prior years, the spring was wetted 100% of the days measured across entire years.

Figure 8. Area chart showing the spring was wet continuously from spring 2017 through the 2024 visit except for a period from April 2021 through fall 2022 when the data were missing.
Figure 8. Water persistence through 27 October 2024 in Shake Spring, Chiricahua National Monument. White areas indicate dates before sensors were first deployed or after the 2024 visit. Black diamonds indicate sensor deployment dates.

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Discharge was not measured in 2024 at the primary sampling location. It was mistakenly measured at a different location, but we will resume discharge measurements at the primary sampling location in 2025. Past data are summarized in Table 5. Wetted extent was evaluated using a method for flowing water. The total springbrook length was 99.0 m (324.8 ft). In the past, springbrook lengths ranged from 30.9 m (101.4 ft) to an estimated length between 100 and 200 m (328–656 ft). In 2024, width and depth along the springbrook averaged 110.8 cm (43.6 in) and 2.1 cm (0.8 in), respectively. The average springbrook width was greater and depth was shallower than previously recorded (Table 6).

Table 5. Discharge data (L/min; mean ± SD) for Shake Spring in 2024 and a range of means from prior years. c.n.s. = could not sample.
Sampling Location 2024 Mean
(Range of Prior Means)		 Prior Years Measured
(# of Visits with Measurements)
001 c.n.s. (5.7–12.8) 2017–2021 (4)

Table 6. Length and average (± SD) width and depth of Shake Spring (measured within the first 100 m of springbrook length) in 2024 and ranges of length values and width and depth means from prior years.
Measurement 2024 Value
(Range of Prior Values/Means)		 Prior Years Measured
(# of Visits with Measurements)
Width (cm) 110.8 ± 119.4 (56.1–100.5) 2017–2023 (6)
Depth (cm) 2.1 ± 3.0 (2.5–8.5) 2017–2023 (6)
Length (m) 99.0 (30.9–98.6) 2017–2023 (6)

Water Quality

Core water quality (Table 7) and water chemistry (Table 8) data were collected at the primary sampling location. In 2024, dissolved oxygen was lower than in past years, while values for pH, specific conductivity, temperature, and total dissolved solids were within previously recorded ranges. Water chemistry values were all within the ranges recorded in prior years.

Table 7. Core water quality data for Shake Spring in 2024 and a range of values from prior years.
Sampling Location Parameter 2024 Value
(Range of Prior Values)		 Prior Years Measured
(# of Measurements)
001 Dissolved oxygen (mg/L) 4.36 (5.98–6.82) 2017–2023 (7)
001 pH 7.21 (7.12–7.61) 2017–2023 (7)
001 Specific conductivity (µS/cm) 403.7 (336.5–420.5) 2017–2023 (7)
001 Temperature (°C) 14.5 (10.6–15.7) 2017–2023 (8)
001 Total dissolved solids (mg/L) 262 (219–273) 2017–2023 (7)

Table 8. Water chemistry data (mg/L) for Shake Spring in 2024 and a range of values from prior years. b.d.l. = below detection limit.
Sampling Location Parameter 2024 Value
(Range of Prior Values)		 Prior Years Measured
(# of Measurements)
001 Alkalinity (CaCO3) 180 (135–185) 2017–2023 (7)
001 Calcium (Ca) 54 (42–58) 2017–2023 (7)
001 Chloride (Cl) 29 (5–56) 2017–2023 (7)
001 Magnesium (Mg) 1 (b.d.l.–13) 2017–2023 (7)
001 Potassium (K) 1.8 (0.8–2.0) 2017–2023 (7)
001 Sulphate (SO4) 18 (2–38) 2017–2023 (7)

Silver Spur Spring

Silver Spur Spring (Figures 9 and 10) is a rheocrene spring (a spring that emerges into one or more stream channels). Water begins at a stagnant pool in cobble and gravel substrate. The channel continues with intermittent water in a series of large pools. A secondary orifice is present downstream but lacks surface flow to connect it with the main channel. The water is generally cool and clear with algae present in the largest pools. The 2024 visit occurred on 26 October 2024, and the spring contained water.

Figure 9. Pools of water sit in a narrow channel surrounded by piles of large rocks and dirt. The channel is lined by grass bunches and trees.
Figure 9. Silver Spur Spring at Chiricahua National Monument, October 2024. The springbrook includes a series of larger pools connected by a narrow trickle of water.

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Figure 10. A dry stream channel filled with boulders and lined with thick trees and scattered green grass clumps.
Figure 10. Silver Spur Spring at Chiricahua National Monument, October 2024. The dry channel upstream of the orifice has large rocks and a canopy of sycamore trees.

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Site Condition

Silver Spur Spring was slightly disturbed by contemporary human use with trash around the site. We rated the spring slightly disturbed by fire based on charred bark nearby (though the riparian vegetation was unaffected by the fire) and windthrow because there were many downed trees across the site (Figure 11). The spring was moderately disturbed by hiking trails based on trampling of riparian vegetation on the periphery of the spring and a trail nearby. Wildlife burrows and scat were noted and there were deer at the site. No other natural or human-caused disturbances were observed at Silver Spur Spring in 2024.

Figure 11. Left image shows a couple of black charred trees from a past fire that are surrounded by recovered green vegetation and small trees with a few large trees. Right image shows a fallen tree lying across a stream channel surrounded by forest.
Figure 11. Examples of disturbance at Silver Spur Spring in 2024. Left: charred trees from a past fire. Right: fallen logs across the springbrook from windthrow.

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As in past years, we did not observe invasive non-native crayfish or American bullfrog (Rana catesbeiana) at Silver Spur Spring in 2024. We observed one invasive non-native plant species at the spring: 1–5 common mullein plants (Verbascum thapsus, 1–5 plants previously observed in 2022).

We observed three species of obligate/facultative wetland plants in 2024: horsetail (Equisetum sp., a forb previously observed in 2017–2023); sedge (Carex sp., previously observed in 2017–2023); and sycamore (Platanus sp., a tree previously observed in 2018–2023).

eDNA Inventory of Rare Species, Invasive Species, and Pathogens

One water sample was collected and filtered from Silver Spur Spring on 26 October 2024. None of our target organisms, including chytrid fungus and ranavirus, were detected on the filter.

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 12). The temperature sensor indicated that Silver Spur Spring was wetted (contained water) for 300 of 300 days (100%) measured up to the 2024 visit. In prior years, the spring was wetted 76.2–100% of the days measured across entire years.

Figure 12. Area chart showing the spring contained water except for short parts of 2021, 2022, and 2023, when the spring was intermittently dry and the first quarter of 2017 because of missing data.
Figure 12. Water persistence through 26 October 2024 in Silver Spur Spring, Chiricahua National Monument. White areas indicate dates before sensors were first deployed or after the 2024 visit. Black diamonds indicate sensor deployment dates.

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Discharge was not measured in 2024 at the primary sampling location; we have not been able to get discharge data since 2019. Past data are summarized in Table 9. Wetted extent was evaluated using a method for flowing water. The total springbrook length was 79.5 m (260.8 ft). In the past, springbrook lengths ranged from 63.1 to 79.9 m (207.0 to 262.1 ft). In 2024, width and depth along the springbrook averaged 133.1 cm (52.4 in) and 4.1 cm (1.6 in), respectively. The average springbrook length, width, and depth in 2024 were all within the ranges recorded in prior years (Table 10).

Table 9. Discharge data (L/min; mean ± SD) for Silver Spur Spring in 2024 and a range of means from prior years. c.n.s. = could not sample.
Sampling Location 2024 Mean
(Range of Prior Means)		 Prior Years Measured
(# of Visits with Measurements)
001 c.n.s. (0.05–2.70) 2018–2019 (2)

Table 10. Length and average (± SD) width and depth of Silver Spur Spring (measured within the first 100 m of springbrook length) in 2024 and a range of length values and width and depth means from prior years.
Measurement 2024 Value
(Range of Prior Values/Means)		 Prior Years Measured
(# of Visits with Measurements)
Width (cm) 133.1 ± 72.0 (100.3–144.5) 2017–2023 (6)
Depth (cm) 4.1 ± 3.6 (2.3–9.4) 2017–2023 (6)
Length (m) 79.5 (63.1–79.9) 2017–2023 (6)

Water Quality

Core water quality (Table 11) and water chemistry (Table 12) data were collected at the primary sampling location. In 2024, dissolved oxygen, pH, specific conductivity, temperature, and total dissolved solids were all within the ranges recorded in prior years. Values for alkalinity, chloride, magnesium, and potassium were within the ranges recorded in prior years, while calcium and sulphate values were lower than previous measurements.

Table 11. Core water quality data for Silver Spur Spring in 2024 and a range of values from prior years.
Sampling Location Parameter 2024 Value
(Range of Prior Values)		 Prior Years Measured
(# of Measurements)
001 Dissolved oxygen (mg/L) 2.02 (1.70–7.88) 2017–2023 (7)
001 pH 7.04 (6.58–7.33) 2017–2023 (7)
001 Specific conductivity (µS/cm) 290.7 (284.7–333.7) 2017–2023 (7)
001 Temperature (°C) 18.9 (14.4–19.0) 2017–2023 (8)
001 Total dissolved solids (mg/L) 189 (185–217) 2017–2023 (7)

Table 12. Water chemistry data (mg/L) for Silver Spur Spring in 2024 and a range of values from prior years.
Sampling Location Parameter 2024 Value
(Range of Prior Values)		 Prior Years Measured
(# of Measurements)
001 Alkalinity (CaCO3) 80 (75–150) 2017–2023 (7)
001 Calcium (Ca) 4 (16–40) 2017–2023 (7)
001 Chloride (Cl) 12 (1–15) 2017–2023 (7)
001 Magnesium (Mg) 5 (1–9) 2017–2023 (7)
001 Potassium (K) 1.0 (0.6–2.4) 2017–2023 (7)
001 Sulphate (SO4) 0 (1–52) 2017–2023 (7)

Literature Cited

Author Information

Elora Ormand 1

Elizabeth Schnaubelt 1

Cheryl McIntyre 1 ORCID ID Logo https://orcid.org/0000-0001-7554-7586

Andy Hubbard 1 ORCID ID Logo https://orcid.org/0000-0002-4223-7730

Edited by Tani Hubbard 2 ORCID ID Logo https://orcid.org/0009-0009-8777-4773

1 National Park Service
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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