Hydrogeologic characteristics and geospatial analysis of water-table changes in the alluvium of the lower Arkansas River Valley, southeastern Colorado, 2002, 2008, and 2015

Michael J. Holmberg

doi:10.3133/sim3378

Home/Archive/USGS

USGS · sim3378

Hydrogeologic characteristics and geospatial analysis of water-table changes in the alluvium of the lower Arkansas River Valley, southeastern Colorado, 2002, 2008, and 2015

Michael J. Holmberg

View original source ↗Read source document ↗Export metadata ↓

Abstract

The U.S. Geological Survey in cooperation with the Lower Arkansas Valley Water Conservancy District measures groundwater levels periodically in about 100 wells completed in the alluvial material of the Arkansas River Valley in Pueblo, Crowley, Otero, Bent, and Prowers Counties in southeastern Colorado, of which 95 are used for the analysis in this report. The purpose of this report is to provide information to water-resource administrators, managers, planners, and users about groundwater characteristics in the alluvium of the lower Arkansas Valley extending roughly 150 miles between Pueblo Reservoir and the Colorado-Kansas State line. This report includes three map sheets showing (1) bedrock altitude at the base of the alluvium of the lower Arkansas Valley; (2) estimated spring-to-spring and fall-to-fall changes in water-table altitude between 2002, 2008, and 2015; and (3) estimated saturated thickness in the alluvium during spring and fall of 2002, 2008, and 2015, and thickness of the alluvium in the lower Arkansas Valley. Water-level changes were analyzed by geospatial interpolation methods. Available data included all water-level measurements made between January 1, 2001, and December 31, 2015; however, only data from fall and spring of 2002, 2008, and 2015 are mapped in this report. To account for the effect of John Martin Reservoir in Bent County, Colorado, lake levels at the reservoir were assigned to points along the approximate shoreline and were included in the water-level dataset. After combining the water-level measurements and lake levels, inverse distance weighting was used to interpolate between points and calculate the altitude of the water table for fall and spring of each year for comparisons. Saturated thickness was calculated by subtracting the bedrock surface from the water-table surface. Thickness of the alluvium was calculated by subtracting the bedrock surface from land surface using a digital elevation model. In order to analyze the response of the alluvium to varying environmental and anthropogenic conditions, the percentage of area of the lower Arkansas Valley showing an absolute change of 3 feet or less was calculated for each of the six water-table altitude change maps. For fall water-table altitude change maps, the periods between 2002 and 2008, 2008 and 2015, and 2002 and 2015 showed that 86.5 percent, 85.2 percent, and 66.3 percent of the study area, respectively, showed a net change of 3 feet or less. In the spring water-table altitude change maps these periods showed a net change of 3 feet or less in 94.4 percent, 96.1 percent, and 90.2 percent of the study area, respectively. While the estimated change in water-table altitude was slightly greater and more variable in fall-to-fall comparisons, these high percentages of area with relatively small net changes indicated that, at least in comparisons of the years presented, there was not a large amount of fluctuation in the altitude of the water table. The saturated thickness in the lower Arkansas Valley was between 25 and 50 feet in 34.4 to 35.9 percent of the study area, depending on the season and year. Between 30.2 and 35.6 percent of the area showed saturated thicknesses between 0 and 25 feet. Less than 1 percent of the area showed a saturated thickness greater than 200 feet in all mapped seasons and years.

Explore related subjects

Scientific Investigations Map Report

Source-reported bounding extent: 37.93986540897977° to 38.29424797320529° latitude; -104.66125488281249° to -102.041015625° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Michael J. Holmberg. 2017-05-15. Hydrogeologic characteristics and geospatial analysis of water-table changes in the alluvium of the lower Arkansas River Valley, southeastern Colorado, 2002, 2008, and 2015. https://doi.org/10.3133/sim3378

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

Map depicting locations susceptible to landslide hazards triggered by prolonged intense rainfall, Utuado Municipio, Puerto Rico

Introduction Landslides commonly occur in Puerto Rico during or soon after rainstorms with prolonged intense rainfall. Rainfall-triggered landslides present significant hazards to the built environment and human safety (for example, Jibson, 1986; Larsen and Torres Sanchez, 1992; Bessette-Kirton and others, 2019a). These hazards were illustrated during September 2017 (Hughes and others, 2019) when Hurricane María triggered more than 70,000 landslides across Puerto Rico (fig. 1), causing loss of life and widespread destruction (figs. 2–4). In Utuado Municipio, about 18,000 landslides were observed after Hurricane María (Hughes and others, 2019). Most intense rainfall-triggered landslides in Puerto Rico occur in soil overlying bedrock and travel downslope from where they initiate (for example, Jibson, 1986; Bessette-Kirton and others, 2019a, 2020). Hazards to human life and infrastructure can differ substantially between where landslides initiate and where they travel. At landslide initiation locations, the ground breaks up (fails) as it moves downslope, removing support for buildings, roadways, and other structures located upon the landslides (fig. 3A, B). This ground failure often causes structures to collapse and suffer severe damage or complete destruction, rendering building occupants at extreme risk. Roadways and other vital infrastructure, such as water, power, and communication lines, are often severed. During intense rainfall events, landslide initiation and movement downslope can occur in seconds to hours. Downslope from where they initiate, landslides in Puerto Rico often move very rapidly (faster than a person can walk or run) and can impact and destroy or fill structures with mud and debris (fig. 4) as well as bury roadways (fig. 3A, C). Moving landslides present extreme hazards to human safety; some fatalities during Hurricane María resulted from mud and debris that flowed through windows and doors of a home and buried occupants. Many landslides in Puerto Rico become fast-moving liquefied masses (debris flows), which are especially common in channels where they can quickly travel kilometers downstream. Multiple debris flows may occur in a channel during a single rainstorm (some channels experienced more than 50 debris flows during Hurricane María; Bessette-Kirton and others [2020] ). This hazard map separately depicts locations and the relative likelihood of where landslides may initiate, where they may move downslope, and where channelized debris flows may travel during or soon after intense rainfall like that during Hurricane María. An estimated average of 399 millimeters of rainfall fell across Utuado during September 19–21, 2017 (Ramos-Scharrón and Arima, 2019). Lower rainfall amounts, durations, and intensities also trigger landsliding in Puerto Rico, although landslides and debris flows become more numerous as rainfall intensities, durations, and cumulative amounts increase. The map does not show potential landslide locations in the karst terrain of northern Utuado (Bawiec, 1999) because Hurricane María-induced landslides were very sparse in this region (Hughes and others, 2019; Baxstrom and others, 2021a), even though rainfall amounts were similar to those in other parts of Utuado. Based on data from Hughes and others (2019), landslides were about 10 times more likely to occur outside of the karst terrane than within it, and our preliminary analyses indicated relatively low susceptibility to rainfall-induced landslide hazards within the karst. Landslide-prone soils appear to be poorly developed on the very steep slopes present in the karst region, where weathering by dissolution appears to dominate.

Puerto Rico, Utuado Municipio↗

USGS2026

Map depicting locations susceptible to landslide hazards triggered by prolonged intense rainfall, Naranjito Municipio, Puerto Rico

Introduction Landslides commonly occur in Puerto Rico during or soon after rainstorms with prolonged intense rainfall. Rainfall-triggered landslides present significant hazards to the built environment and human safety (for example, Jibson, 1986; Larsen and Torres Sanchez, 1992; Bessette-Kirton and others, 2019a). These hazards were illustrated during September 2017 (Hughes and others, 2019), when Hurricane María triggered more than 70,000 landslides across Puerto Rico (fig. 1), causing loss of life and widespread destruction (figs. 2–4). In Naranjito Municipio, about 2,000 landslides were observed after Hurricane María (Hughes and others, 2019). Most intense-rainfall-triggered landslides in Puerto Rico occur in soil overlying bedrock and travel downslope from where they initiated (for example, Jibson, 1986; Bessette-Kirton and others, 2019a; 2020). Hazards to human life and infrastructure can differ substantially between where landslides initiate and where they travel. At landslide initiation locations, the ground breaks up (fails) as it moves downslope, removing support for buildings, roadways, and other structures located upon the landslides (figs. 3B, 4A, B). This ground failure often causes structures to collapse and suffer severe damage or complete destruction, rendering building occupants at extreme risk. Roadways and other vital infrastructure, such as water, power, and communication lines are often severed. During intense rainfall events, landslide initiation and movement downslope can occur in seconds to hours. Downslope from where they initiate, landslides in Puerto Rico often move, or runout, very rapidly (faster than a person can walk or run) and can impact and destroy or fill structures with mud and debris (figs. 3A, 4A, C) as well as bury roadways (fig. 4A). Moving landslides present extreme hazards to human safety; some fatalities during Hurricane María resulted from mud and debris that flowed through windows and doors of a home and buried occupants. Many landslides in Puerto Rico become fast-moving debris flows, which are especially common in channels where they can quickly travel kilometers downstream. Multiple debris flows may occur in a channel during a single rainstorm (some channels experienced more than 50 debris flows during Hurricane María; Bessette-Kirton and others, 2020). This map separately depicts locations and the relative likelihood of where landslides may initiate, where they may move downslope, and where channelized debris flows may travel during or soon after intense rainfall like that during Hurricane María. An estimated average of 529 millimeters of rainfall fell across Naranjito during September 19–21, 2017 (Ramos-Scharrón and Arima, 2019). Lower rainfall amounts, durations, and intensities also trigger landsliding in Puerto Rico, although landslides and debris flows become more numerous as rainfall intensities, durations, and cumulative amounts increase.

Naranjito Municipio, Puerto Rico↗

USGS2026

Map depicting locations susceptible to landslide hazards triggered by prolonged intense rainfall, Lares Municipio, Puerto Rico

Introduction Landslides commonly occur in Puerto Rico during or soon after rainstorms with prolonged intense rainfall. Rainfall-triggered landslides present significant hazards to the built environment and human safety (for example, Jibson, 1986; Larsen and Torres Sanchez, 1992; Bessette-Kirton and others, 2019a). These hazards were illustrated during September 2017 (Hughes and others, 2019), when Hurricane María triggered more than 70,000 landslides across Puerto Rico (fig. 1), causing loss of life and widespread destruction (figs. 2 and 3). In Lares Municipio, about 3,500 landslides were observed after Hurricane María (Hughes and others, 2019). Most intense-rainfall-triggered landslides in Puerto Rico occur in soil overlying bedrock and travel downslope from where they initiated (for example, Jibson, 1986; Bessette-Kirton and others, 2019a; 2020). Hazards to human life and infrastructure can differ substantially between where landslides initiate and where they travel. At landslide initiation locations, the ground breaks up (fails) as it moves downslope, removing support for buildings, roadways, and other structures located upon the landslides (figs. 2, 3A, B). This ground failure often causes structures to collapse and suffer severe damage or complete destruction, rendering building occupants at extreme risk. Roadways and other vital infrastructure, such as water, power, and communication lines are often severed. During intense rainfall events, landslide initiation and movement downslope can occur in seconds to hours. Downslope from where they initiate, landslides in Puerto Rico often move, or runout, very rapidly (faster than a person can walk or run) and can impact and destroy or fill structures with mud and debris (figs. 3A, C) as well as bury roadways (fig. 3A). Moving landslides present extreme hazards to human safety; some fatalities during Hurricane María resulted from mud and debris that flowed through windows and doors of a home and buried occupants. Many landslides in Puerto Rico become fast-moving debris flows, which are especially common in channels where they can quickly travel kilometers downstream. Multiple debris flows may occur in a channel during a single rainstorm (some channels experienced more than 50 debris flows during Hurricane María; Bessette-Kirton and others, 2020). This map separately depicts locations and the relative likelihood of where landslides may initiate, where they may move downslope, and where channelized debris flows may travel during or soon after intense rainfall like that during Hurricane María. An estimated average of 256 millimeters of rainfall fell across Lares during September 19–21, 2017 (Ramos-Scharrón and Arima, 2019). Lower rainfall amounts, durations, and intensities also trigger landsliding in Puerto Rico, although landslides and debris flows become more numerous as rainfall intensities, durations, and cumulative amounts increase. The map does not show potential landslide locations in the karst terrain of northern Lares (Bawiec, 1999) because Hurricane María-induced landslides were very sparse in this region (Hughes and others, 2019; Baxstrom and others, 2021a), even though rainfall amounts were similar to those in other parts of Lares. Based on data from Hughes and others (2019), landslides were about ten times more likely to occur outside of the karst terrane than within it, and our preliminary analyses indicate relatively low susceptibility to rainfall-induced landslide hazards within the karst. Landslide-prone soils appear to be poorly developed on the very steep slopes present in the karst region, where weathering by dissolution appears to dominate.

Lares Municipio, Puerto Rico↗