Climate and Water Monitoring at Pecos National Historical Park: Water Year 2022

Pecos River, Pecos National Historical Park, New Mexico.

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Overview

Together, climate and hydrology shape ecosystems and the services they provide, particularly in arid and semi-arid ecosystems and across the Southern Plains (Woodhouse and Overpeck 1998). Understanding changes in climate, groundwater, and surface water is key to assessing the condition of park natural resources—and often, cultural resources.

At Pecos National Historical Park (Figure 1), Southern Plains 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 Pecos National Historical Park, 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 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 groundwater monitoring at Pecos National Historical Park in WY2022.

Reference: Woodhouse, C. A., and J. T. Overpeck. 1998. 2000 years of drought variability in the central United States. Bulletin of the American Meteorological Society 79(12): 2693–2714. https://doi.org/10.1175/1520-0477(1998)079%3C2693:YODVIT%3E2.0.CO;2.

Figure 1. Weather station and groundwater wells at Pecos National Historical Park.

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Mission church, built in 1717, at Pecos National Historical Park.

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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 (Pecos National Monument #296676) has been operational at Pecos National Historical Park since 1916 (see Figure 1). This station typically provides a reliable climate dataset. However, in WY2022 the station was missing data for 107 days. As a substitute, climate analyses in this report use 30-year averages (1991–2020) and gridded surface meteorological (GRIDMET) data from the location of the station. Subsequent reports may revert to the weather stations as the data source depending on future data quality.

GRIDMET is a spatial climate dataset at a 4-km resolution that is interpolated using weather station data, topography, and other observational and modeled land-surface data. Temperature and precipitation estimated from GRIDMET may vary from actual weather at a particular location depending on the availability of weather station data and the difference in elevation between the location of interest and that assigned to a grid cell. Data from both weather stations and GRIDMET are accessible through Climate Analyzer.

Results for Water Year 2022

Precipitation

Annual precipitation at Pecos National Historical Park in WY2022 was 17.65″ (44.8 cm; Figure 2), 1.56″ (4.0 cm) more than the 1991–2020 annual average. October, November, April, and May were very dry, while rainfall in winter (December–March) and early monsoon season (June–August) was greater than the 1991–2020 annual average. June 2022 precipitation, at 3.87″ (9.8 cm), was over three times the 1991–2020 monthly average of 1.18″ (3.0 cm).

Air Temperature

The mean annual maximum temperature in WY2022 was 66.8°F (19.3°C), 1.0°F (0.6°C) above the 1991–2020 average. The mean annual minimum temperature in WY2022 was 34.6°F (1.4°C), 0.3°F (0.2°C) above the 1991–2020 average. Mean monthly maximum and minimum temperatures in WY2022 differed by as much as 8.1°F (4.5°C; see February as an example) from the 1991–2020 monthly averages (Figure 2).

Figure 2. Climogram showing monthly precipitation and mean maximum and minimum air temperatures in water year 2022 (WY2022) and the 1991–2020 means at Pecos National Historical Park. Data source: GRIDMET via 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 Pecos National Historical Park indicates that WY2022 was slightly wetter 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. Reconnaissance drought index for Pecos National Historical Park, water years 1991–2022. 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: GRIDMET via climateanalyzer.org.

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Grassland at Pecos National Historical Park.

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Groundwater 

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

Methods

Pecos National Historical Park groundwater is monitored in two wells (Figure 1). The New Mexico Bureau of Geology and Mineral Resources began monitoring both wells in 2020. The well at the trading post (WL-0206) is monitored continuously and the well at the Glorieta Battlefield Trail (WL-0207) is monitored annually. The data are available at the Healy Collaborative Groundwater Monitoring Network.

Recent Findings 

Groundwater levels in WY2022 were stable and relatively shallow (Table 1 and Figure 4). The average depth to water at WL-0206 was 41.68 ft below ground surface (bgs; 12.70 m bgs); however, this includes measurements recorded when the well was pumping or recently pumped. Pumping can cause temporary decreases in water level of up to 20 ft. Therefore, the WL-0206 static water level was likely a little higher than was measured on this date. No water level measurement was collected at WL-0207 in WY2022; however, a measurement was made shortly after the start of WY2023 and is included here. Water level in WL-0207 was slightly higher than the previous two measurements.

Table 1. Groundwater Monitoring Results (click on this tab to view table)

Table 1. Groundwater monitoring results in water year 2022 (WY2022), Pecos National Historical Park (amsl = above mean sea level; bgs = below ground surface).

*WL-0207 measurement collected in water year 2023: October 6, 2023.

State Well Number	Location	Wellhead Elevation (ft amsl)	Mean Depth to Water (ft bgs)	Mean Water Level Elevation (ft amsl)	Change in Elevation from WY2021 (± ft)
WL-0206	Trading post	6833.00	41.68	6,791.32	−0.34
WL-0207	Glorieta Battlefield Trail	7330.00	33.84*	7,296.16	0.25

Figure 4. Depth to water in ft below ground surface (bgs) at two groundwater monitoring wells in water years 2020–2022, Pecos National Historical Park. White circles indicate manual measurements collected when the well was being pumped or was recently pumped.

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Past Reports

Water Year 2021 Climate and Weather Monitoring at Pecos National Historical Park.

Article created by the Southern Plains Inventory and Monitoring Network.

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