Salinity yield modeling of the Upper Colorado River Basin using 30-meter resolution soil maps and random forests

Water Resources Research
By: , and 

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Abstract

Salinity loading in the Upper Colorado River Basin (UCRB) costs local economies upwards of $300 million US dollars annually. Salinity source models have generally included coarse spatial data to represent non‐agriculture sources. We developed new predictive soil property and cover maps at 30 m resolution to improve source representation in salinity modeling. Salinity loading erosion risk indices were also created based on soil properties, remotely sensed bare ground exposure, and topographic factors to examine potential surface soil erosion drivers. These new maps and data from previous SPARROW models were related to recently updated records of salinity at 309 stream gauges in the UCRB using random forest regressions. Resulting salinity yield predictions indicate more diffuse salinity sources, with slightly higher yields in more arid portions of the UCRB, and less overall load coming from irrigated agricultural sources. Model simulations still indicate irrigation to be the major human source of salinity (661,000 Mg, or 12%), but also suggest that 75,000 Mg (1.4%) of annual salinity in the UCRB is coming from areas with excessive exposed bare ground in high elevation mountain areas. Model inputs allow for field scale screening of locations that could be targeted for salinity control projects. Results confirm recent studies indicating limited surface erosional influence on salinity loading in UCRB surface waters, but impacts of monsoonal runoff events are still not fully understood, particularly in drylands. The study highlights the utility of new predictive soil maps and machine learning for environmental modeling.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Salinity yield modeling of the Upper Colorado River Basin using 30-meter resolution soil maps and random forests
Series title Water Resources Research
DOI 10.1029/2018WR024054
Volume 55
Issue 6
Year Published 2019
Language English
Publisher American Geophysical Union
Contributing office(s) California Water Science Center, Utah Water Science Center, Southwest Biological Science Center
Description 20 p.
First page 4954
Last page 4973
Country United States
State Arizona, Colorado, New Mexico, Utah, Wyoming
Other Geospatial Upper Colorado River Basin