Article

Climate and Water Monitoring at Amistad National Recreation Area: Water Year 2022

Amistad National Recreation Area

A rocky shoreline and a large rippling lake under an orange and yellow sky.
Amistad Reservoir at Amistad National Recreation Area. The reservoir receives water from basins in the U.S. and Mexico, including the Rio Grande, the Pecos River, and the Devils River.

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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 Amistad National Recreation Area (Figure 1), Chihuahuan 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 problems, allowing managers to mitigate them before they become worse. At Amistad National Recreation Area, we monitor climate and groundwater, reservoir level, and springs, among other vital signs.

Surface-water and groundwater 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 the results of climate and water monitoring at Amistad National Recreation Area (Figure 1) in WY2022

Map of Amistad National Recreation Area showing 6 groundwater wells and one weather station in and around the park. Four wells and the weather station are along the reservoir, one is on the Devils River and one on the Pecos River.
Figure 1. Monitored weather station and groundwater wells at Amistad National Recreation Area.

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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 Cooperative Observer Program (NOAA COOP) weather station (Amistad Dam #410225) has been operational at Amistad National Recreation Area since 1964 (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.

Two saucer shaped clouds over a desert hill.
Lenticular clouds at Amistad National Recreation Area.

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Results for Water Year 2022

Precipitation

Annual precipitation at Amistad Dam in WY2022 was 11.82″ (30.0 cm; Figure 2), 7.61″ (19.3 cm) less than the 1991–2020 annual average. This deficit resulted from no or substantially less than average rainfall in six different months (November, January, February, March, June, and July). However, April and August received 43–46% more rainfall than the 1991–2020 monthly averages, 0.54″ (1.4 cm) and 1.16″ (2.9 cm) more, respectively. Extreme daily rainfall events (≥ 1″; 2.54 cm) occurred on 4 days, one less than the 1991–2020 average annual frequency of 5.1 days. Extreme rainfall events occurred on 01 October 2021 (1.22″; 3.1 cm), 02 May 2022 (1.13″; 2.9 cm), 16 August 2022 (1.20″; 3.0 cm), and 30 August 2022 (1.14″; 2.9 cm).

Air Temperature

The mean annual maximum temperature at Amistad Dam in WY2022 was 84.3°F (29.1°C), 3.3°F (1.8°C) above the 1991–2020 average. The mean annual minimum temperature in WY2022 was 59.7°F (15.4°C), 1.7°F (0.9°C) above the 1991–2020 average. Mean monthly maximum and minimum temperatures in WY2022 were generally warmer than average or near average for most of the year and differed by as much as 10.3°F (5.7°C; see December as an example) relative to the 1991–2020 monthly averages (Figure 2). However, cooler than average temperatures were observed in January, February, and March. Extremely hot temperatures (≥ 102°F; 38.9°C) occurred on 39 days in WY2022, nearly twice the 1991–2020 average frequency of 21.5 days. Extremely cold temperatures (≤ 35°F; 1.7°C) occurred on 30 days, 50% more than the average frequency of 20.1 days.

Climogram showing precipitation totals for water year 2022 are lower than the long-term average in all but two months. Max and min temperature averages are higher in water year 2022 than average in most months.
Figure 2. Climogram showing monthly precipitation and mean maximum and minimum air temperatures in water year (WY) 2022 and the 1991–2020 averages at Amistad Dam weather station, Amistad National Recreation Area. 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 Amistad National Recreation Area indicates that WY2022 was 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.

Figure 3. bar graph showing conditions in water years 2021 and 2022 are drier than the 1991 to 2022 average.
Figure 3. Reconnaissance drought index for Amistad Dam station in water years (WY) 1991–2022, Amistad National Recreation Area. Drought index calculations are relative to the time period selected (1990–2022). Choosing a different set of start/end points may produce different results. Data source: climateanalyzer.org.

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A large, rippling, blue lake lined by sheer rock cliffs topped by desert vegetation and a long bridge in the distance.
Amistad Reservoir

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Reservoir Level

The Amistad International Reservoir was formed by the construction of Amistad Dam between 1964 and 1969. Reservoir level is not a Chihuahuan Desert Network vital sign; however, it is included in this report because the reservoir level has implications for park resources throughout Amistad National Recreation Area, including groundwater and springs.

Methods

The International Boundary and Water Commission (IBWC) has operated a water level gage at Amistad Reservoir (International Amistad Reservoir Storage Station Number 08-4508.00) since 1968 when filling began. The gage is located at the downstream end of the reservoir. Every 15 minutes, the gage collects water level data, which are available from the IBWC and the Texas Water Development Board (TWDB).

Recent Findings 

Mean reservoir level in WY2022 was 1,064.75 feet above mean sea level (ft amsl; 324.53 m amsl) with a range of 1,052.47 to 1,075.18 ft amsl (320.79–327.71 m amsl; Figure 4). For the entire year, reservoir level remained below the flood pool elevation (1,140.4 ft, 347.59 m; elevation of flood gates and emergency spillway) and the conservation pool elevation (1,117.0 ft, 340.46 m; maximum normal operating level, above which the storage is used to regulate floodwaters). Throughout the year, the reservoir ranged from 30–52% full. Daily reservoir water level in WY2022 was on average 52.25 ft (15.93 m) below the conservation pool and 27.89 ft (8.50 m) below the mean water level for 1991–2020. Reservoir level dropped below the 1991–2020 minimum during two periods: 5 April to 19 April 2022 and 27 June to 01 September 2022.

Figure 4. Line graph showing water levels in the reservoir in water year 2022 were below the flood pool and conservation pool elevations and were closer to long-term minimum average water levels.
Figure 4. Daily Amistad Reservoir water level elevation in water year (WY) 2022 with the flood and conservation pool elevations and the 1991–2020 average daily mean, maximum, and minimum levels.

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Groundwater 

Groundwater is one of the most critical natural resources of the American Southwest, providing drinking water, irrigating crops, and sustaining rivers, streams, and springs throughout the region.  

Methods

Amistad National Recreation Area groundwater is monitored using six wells in or near the recreation area (Figure 1). Each well is monitored annually by the Texas Water Development Board (TWDB) and the data are available at the TWDB Database.

Results of Water Year 2022

Well 7140201 could not be measured, possibly due to a well collapse. Groundwater levels in the remaining five monitored wells decreased between WY2020 and WY2022 (Table 1 and Figure 5); groundwater at the park was not monitored by TWDB in WY2021 due to Covid-19 disruptions to fieldwork). These decreases were consistent with a 16.35 ft (4.98 m) decrease in reservoir level when groundwater was sampled in WY2022 compared to WY2020. Groundwater levels in wells 7033302 and 7140307 are on the periphery of the reservoir and were 4.85 ft (1.48 m) and 10.08 ft (3.07 m) below the level of the reservoir, respectively. The water level in 7033508 was 161.35 ft (49.18 m), the lowest recorded water level since monitoring began in 2000 and 55.23 ft (16.83 m) below the reservoir water level. The well was not pumping during the measurement, but TWDB noted that nearby pumping may be causing this low water level. Water levels in wells 7017403 and 7122403 were both substantially higher than the reservoir level because they are up gradient of the reservoir, adjacent to the Devils River and the Pecos River, respectively.

Figure 5. Line graph showing water levels in four of the wells generally increase and decrease with reservoir elevation though one could not be sampled in 2022, and two wells are more stable and at a higher elevation than the reservoir water level.
Figure 5. Water level elevation in feet above mean sea level (ft amsl) in six groundwater monitoring wells and Amistad Reservoir at Amistad National Recreation Area, 1964–2022.

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Springs

Background

Springs, seeps, and tinajas (small 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?). Springs reporting is by water year (WY), which begins in October of the previous calendar year and goes through September of the current calendar year (e.g., WY2022 runs from October 2021 through September 2022). Springs sampling for WY2022 at Amistad National Recreation Area occurred between 12 April and 14 April 2022, except for water persistence, which is monitored continuously throughout the water year.

List of Springs

Scroll down or click on a spring below to view monitoring results.

Dead Man's Canyon Spring ǀ Indian Springs Canyon Spring

Green vegetation bursts forth from a white rock wall, hiding the bottom 7 feet or so of the rock. A pool of water runs along the rock wall base below the vegetation.
Figure 6. Dead Man’s Canyon Spring at Amistad National Recreation Area, April 2022.

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WY2022 Findings at Dead Man's Canyon Spring

Dead Man’s Canyon Spring (Figure 6 above) is a hanging garden spring (a complex, multi-habitat spring that emerges along geologic contacts and seeps onto underlying walls) located in Dead Man’s Canyon, a side canyon flowing into the Pecos River. Here, water seeps from along a cliff face and drips down onto underlying walls, supporting a robust community of wetland plants clinging to the rock, and small, shallow pools are hidden behind the vegetation. Flow from the hanging garden joins flow from two other orifices inside the canyon bottom. The WY2022 visit occurred on 13 April 2022, and Dead Man’s Canyon Spring was wetted (contained water).

Site Condition

In WY2022, Dead Man’s Canyon Spring was slightly disturbed from grazing by aoudad, or Barbary sheep (Ammotragus lervia), an introduced invasive bovine from North Africa. We ranked the spring as slightly disturbed from native wildlife (digging, scat, and browse), higher than in previous years. WY2022 was the first time that the spring was rated slightly disturbed from drying, with the overall spring ecosystem noticeably drier and reduced in extent as compared to past years. No other natural or human-caused disturbances were observed at Dead Man’s Canyon Spring in WY2022.

We did not find American bullfrog (Lithobates catesbeianus), a non-native, invasive animal. As in most past years, we detected a pair of invasive plants: scattered patches of the wetland obligate giant reed (Arundo donax) and a few (≤ 5) tree tobacco (Nicotiana glauca) plants. We observed cattail (Typhaceae sp.) and maidenhair fern (Adiantum sp.), obligate wetland plants that have been consistently observed at Dead Man’s Canyon Spring since monitoring started in 2017. In WY2022, we detected sedge (Carex sp.) for the first time.

Water Quantity

We were unable to sample the site or replace sensors in WY2021, so the temperature sensors (used to estimate spring persistence) lost power well before our WY2022 visit, resulting in considerable missing data (Figure 7). In prior water years, the spring was wetted 99.7–100% of the days measured.

Area chart show the spring was consistently wet from October 2017 to July 2020. There are missing data in summer of WY2017, winter of WY2018, and from July 2020 to September of 2022.
Figure 7. Water persistence in Dead Man’s Canyon Spring, Amistad National Recreation Area.

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Discharge was estimated at 1.3 (± 0.2) L/min (0.3 ± 0.1 gal/min) in WY2022—only 10–20% of the flow observed in past years (Table 2). Conversely, wetted extent was greater, particularly springbrook length, which was five times longer than the previous longest observation (Table 3).

We attribute this somewhat strange combination—dramatically lower discharge coupled with a much larger wetted extent—to changes in the water levels in the adjacent Amistad Reservoir. The reservoir level was lower than measured in previous years, such that the springbrook had a longer distance to travel to reach the reservoir. And reduced reservoir levels likely reduced the hydraulic head of groundwater supporting the spring, leading to reduced discharge and the drying disturbance noted for the first time in WY2022.

Water Quality

Core water quality (Table 4) and water chemistry (Table 5) data were collected at the primary sampling location. Dissolved oxygen was within range of prior values, while specific conductivity and total dissolved solids were slightly higher, and pH and water temperature were lower. Alkalinity, magnesium, and sulphate were within range of prior values, while calcium was slightly lower, and chloride and potassium were higher. The values are presented in the tables below along with ranges of prior values (2017–2019).

Dead Man's Canyon Spring Data Tables

Three people sitting on bare, open ground next to a pool of water (spring emergence location) next to a narrow section of a lake in a very barren landscape.
Figure 8. Indian Springs Canyon Spring at Amistad National Recreation Area, April 2022.

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WY2022 Findings at Indian Springs Canyon Spring

Indian Springs Canyon Spring (Figure 8 above) is a rheocrene spring (a spring that emerges into one or more stream channels) in Indian Springs Canyon. The spring has a strong hydrologic connectivity to the water level of Lake Amistad. As a result, the location of the primary emergence for this spring fluctuates considerably. The spring can emerge 500 m up the canyon (at Orifice A, as it did in WY2018–WY2020), the mouth of the canyon (at Orifice G, as it did in WY2022), or one or more of the secondary orifices in between. Spring characteristics vary depending on emergence location, but due to the low gradient of the canyon, the spring typically forms standing, elongated pools or a slowly flowing stream over cobble and bedrock. The WY2022 visit occurred on 14 April 2022, and the spring was wetted (contained water) at the mouth of the canyon.

Site Condition

We rated Indian Springs Canyon Spring moderately disturbed from drying, likely reflecting the impacts of relatively low reservoir levels observed in WY2022. As in past years, we also rated the spring slightly disturbed from contemporary human use (trash within the site). The spring was slightly disturbed from livestock, consistent with our past sampling (WY2017–2021). No other natural or human-caused disturbances were observed at Indian Springs Canyon Spring in WY2022.

We did not observe American bullfrog (Lithobates catesbeianus), a non-native, invasive aquatic animal, but did detect a dense matrix of the invasive, exotic bermudagrass (Cynodon dactylon; Figure 9) around the upper springbrook of Indian Springs Canyon Spring. Although bermudagrass had been detected previously in WY2018, it was limited to just a few plants. Scattered patches of tree tobacco (Nicotiana glauca) were also detected for the first time at this spring in WY2022. As in past years, a few lilac chastetrees (Vitex agnus-castus) were observed around the springbrook. No native obligate wetland species were observed at the spring.

A drainage that is otherwise covered in white/tan dirt and rock is bordered by a dense strip of green grass.
Figure 9. Carpet of bermudagrass (Cynodon dactylon) at Indian Springs Canyon Spring, Amistad National Recreation Area, April 2022.

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Water Quantity

The dynamic nature of spring emergence at Indian Springs Canyon Spring makes monitoring persistence throughout the year challenging. A temperature sensor has been deployed at Orifice A since WY2018. This sensor indicated that the spring was wetted (contained water) at that location for 7 of 196 days (3.6%) measured in WY2022 up to our visit on 14 April 2022 (Figure 10). During this visit, the spring was wetted near the mouth of the canyon but not at Orifice A. In prior water years, the spring was wetted at Orifice A 3.8–86.7% of the days measured.

Area chart showing the spring was dry summer 2018, mostly dry between spring 2020 and spring 2022, and mostly wet in summer and fall 2019 and winter 2020. Data are missing in WY2017 and the first halves of WY2018 and WY2019.
Figure 10. Water persistence in Indian Springs Canyon Spring, Amistad National Recreation Area.

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Discharge was not estimated at the primary sampling location in WY2022 due to a lack of surface flow. Discharge data for WY2018 (estimated at 85.8 ± 6.6 L/min [22.6 ± 1.7 gal/min]) are presented in (Table 6).

Wetted extent (Table 7) was evaluated using a method for flowing water. The total brook length was 67.6 m (221.8 ft). Width and depth averaged 4.5 m (14.8 ft), and 18.2 cm (7.2 in), respectively. Overall, wetted extent was on the high end or exceeded the range of previous wetted extent measurements despite the dry nature of the overall site.

Water Quality

Core water quality and water chemistry data were taken where the spring was flowing (Orifice G, sampling location 007), close to the mouth of the canyon. In prior years, water chemistry and water quality data were measured at Orifice A (sampling location 001). Values from 2022 and prior years are presented in Table 8 and Table 9. Additional measurements at each sampling location will provide necessary context for the water quality at the site.

Indian Springs Canyon Spring Data Tables

Report Citation

Authors: Susan Singley, Kara Raymond, Andy Hubbard

Singley, S., K. Raymond, and A. Hubbard. 2024. Climate and Water Monitoring at Amistad National Recreation Area: Water Year 2022. Chihuahuan Desert Network, National Park Service, Las Cruces, New Mexico.

Past Reports

Climate and Water Monitoring at Amistad National Recreation Area: Water Year 2021

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Last updated: March 19, 2025