Browsing by Author "Baker, Anna"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Characterization of streams and rivers in the Minnesota River Basin Critical Observatory: water chemistry and biological field collections, 2013-2016
    (2017-09-06) Dolph, Christine, L.; Hansen, Amy, T.; Kemmitt, Katie, L.; Janke, Ben; Rorer, Michelle; Winikoff, Sarah; Baker, Anna; Boardman, Evelyn; Finlay, Jacques, C.; dolph008@umn.edu; Dolph, Christine, L.
    This dataset was collected to inform the Water, Sustainability and Climate Minnesota River Basin Observatory, and was supported by the National Science Foundation under Grant No. 1209402 Water, Sustainability and Climate (WSC) – Category 2, Collaborative: Climate and human dynamics as amplifiers of natural change: a framework for vulnerability assessment and mitigation planning. The dataset contains point locations, watershed areas and water quality information for 231 ditch, stream, river and wetland sites located in the Le Sueur River, Chippewa River, Cottonwood River, Cannon River, Wantonwan River and Blue Earth River basins of Minnesota. Study sites ranged in size from 1st order ditches and streams to an 8th order river. Each of these sites was sampled at least once between 2013-2016 (most sites were sampled multiple times) for one or more of the following parameters: 1) water chemistry (total dissolved nitrogen, nitrate-N, nitrite-N, ammonium-N, particulate nitrogen, soluble reactive phosphorus, total dissolved phosphorus, particulate phosphorus, total phosphorus, dissolved organic carbon, dissolved inorganic carbon, particulate carbon, chlorophyll a, total suspended solids, volatile suspended solids, delta-H-2 and delta-O-18 stable isotopes of site water, specific UV absorbance (SUVA) of site water, fluorescence index (FI) of site water); 2) stable isotopes (delta-C-13, delta-N-15, delta-H-2) of invertebrate consumers, particulate carbon and potential food sources; 3) denitrification rates and characteristics of benthic sediment in agricultural drainage ditches; and 4) stream discharge. This dataset also includes spatial data files containing study site locations and watershed areas delineated for each site.
  • Thumbnail Image
    Item
    Le Sueur River Basin Sediment Characterization - chemical and physical properties of sediments collected 2015-2018
    (2019-02-14) Baker, Anna; Finlay, Jacques; Gran, Karen; Rorer, Michelle; Belo, Tessa; Atkins, Walter; Muramoto-Mathieu, Megumi; Yetter, Kara; Katherine, Kemmitt; abaker@usgs.gov; Baker, Anna
    These data were collected in support of the development of a watershed budget for sediment-derived phosphorus for the Le Sueur River Basin. This table presents the results of analyses of sediment total phosphorus and extractable dissolved phosphorus (soluble reactive phosphorus, SRP, or dissolved orthophosphate, DOP) and other chemical and physical parameters with potential influence over the phosphorus content of these sediments. This data set consists of 97 samples collected from erosional source areas including agricultural fields and ditches, near channel features such as bluffs, streambanks, and ravines, and from sinks such as channel beds and fluvial suspended sediment.
  • Thumbnail Image
    Item
    Phosphorus-sediment interactions and their implications for watershed scale phosphorus dynamics in the Le Sueur River Basin
    (2018-08) Baker, Anna
    Phosphorus is a leading pollutant of global surface waters, and sediment is a known driver of phosphorus loading to downstream receiving waters. This master’s thesis investigates sources and dynamics of phosphorus in the Le Sueur River basin in southern Minnesota, a highly agricultural watershed whose glacial history has rendered it vulnerable to massive erosion, and which contributes disproportionately to downstream sediment and phosphorus loading. We develop a mass balance for sediment-derived phosphorus, incorporating sediment-total and dissolved phosphorus into a robust sediment budget describing sources and sinks of sediment to this system. This budget explores the extent to which agricultural top soil and upland ditch-banks, and eroding near channel features such as bluffs, stream banks, and ravines, can be implicated for phosphorus loading to this basin. Further, we explore the extent to which in-stream processing alters the fate, bioavailability, and persistence of phosphorus in this system via the incorporation of sorption experimental data into this budget. Our results show that fine (silt and clay sized) source sediment can only account for at most 24% of the total phosphorus exported from the Le Sueur River. These results suggest that sediment and phosphorus sources are largely decoupled, and that if we managed 100% of fine sediment erosion we would only reduce phosphorus loading by 24% or less. Sorption tests were used to examine the role of fine sediment as a source or sink for phosphorus. Results of these tests demonstrate that agricultural sediments donate phosphorus, while near channel sediments bind phosphorus from the water column. Incorporation of these results into our budget indicates that 2-24% of total phosphorus may be in particulate form as a result of in-stream equilibrium processes between sediment and dissolved orthophosphate in the water column. Sorption of dissolved phosphorus by sediment may depress dissolved phosphorus load by as much as 31%. These results point to the importance of understanding dissolved phosphorus source and dynamics, and to the management of both sediment and dissolved phosphorus source being critical to addressing excess phosphorus in this basin.