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Abstract Understanding relationships between stream chemistry and watershed factors: land use/land cover, climate, and lithology are crucial to improving our knowledge of critical zone processes that influence water quality. We compiled major ion data from >100 monitoring stations collected over 60 years (1958–2018) across the Colorado River Watershed in Texas (103,000 km2). We paired this river chemistry data with complementary lithology, land use, climate, and stream discharge information. Machine learning techniques were used to produce new insights on controls of stream water chemical behavior, which were validated using traditional multivariate analyses. Studies on stream flow and chemistry in the American west and globally have shown strong relationships between major ion chemical composition, climate, and lithology which hold true for the Colorado River basin in this study. Reactive minerals, including carbonates and evaporites, dominate major ion chemistry across the upper, low‐precipitation regions of the watershed. Upstream and middle reaches of the Colorado River showed shifts from Na‐Cl‐SO4dominated water from multiple sources including dissolution of gypsum and halite in shallow groundwater, and agricultural activities, to Ca‐HCO3water types controlled by carbonate dissolution. In the lower portion of the watershed multiple analyses demonstrate that stream chemistry is more influenced by greater precipitation and the presence of silicate minerals than the middle and upstream reaches. This study demonstrates the power of applying machine learning approaches to publicly available long term water chemistry data sets to improve the understanding of watershed interactions with surficial lithology, salinity sources, and anthropogenic influences of water quality.
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The Lamprey River Hydrological Observatory: Suburbanization and changing seasonality
Abstract The Lamprey River Hydrological Observatory (LRHO) is a lowland coastal watershed in southeastern New Hampshire (USA). The LRHO offers a platform to investigate the effects of suburbanization and changing seasonality on watershed hydrology, biogeochemistry, and nutrient export to an estuarine ecosystem. The LRHO utilizes a nested‐watershed design to examine headwater stream and main‐stem river dynamics distributed across a mixed land‐use environment. Data sets from the LRHO now comprise over 20 years of weekly grab sample data as well as 7 years of high‐frequency sensor data. Collectively these data sets include measures of discharge, dissolved organic matter, nutrients, cations and anions, greenhouse gases, and other physio‐chemical properties. Here we share information on the setting and motivating questions of the LRHO and data availability.
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- Award ID(s):
- 1929148
- PAR ID:
- 10452727
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Hydrological Processes
- Volume:
- 35
- Issue:
- 4
- ISSN:
- 0885-6087
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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