Quantifying nutrient load reduction practices and export at field and landscape scales

Jul 2023


The Iowa Geological Survey (IGS) will conduct several concurrent projects during the 2023-2024 reporting period focused on quantifying nutrient load reduction practices and nutrient export at field and landscape scales across Iowa.


Overall, the concurrent field and desktop projects conducted by IGS researchers aim to advance efforts to better quantify nutrient reductions at field and landscape scales across Iowa.


  1. A new saturated waterway practice will be designed, installed and monitored at a farm site in eastern Iowa.
    1. A new grass waterway tile system will be installed to direct a portion of drainage water into drainageway sediments for nitrate load reduction.
    2. At two other field sites in eastern Iowa, IGS will characterize pre-BMP conditions and monitor new saturated buffer installations. At one site, monitoring will focus on quantifying multiple systems installed along a single stream reach. At the other site, monitoring will be conducted to assess installation of a saturated buffer downgradient of surface inlets.
  2. Along with field projects, IGS will conduct desktop analyses on two aspects of nutrient export occurring at the Iowa landscape scale.
    1. In one study, IGS will quantify the speciation of N (nitrate, organic nitrogen, and ammonium) and P (particulate phosphorus and orthophosphate) loads at approximately 60 locations within the state’s ambient monitoring network. Spatial and temporal patterns of nutrient speciation will be evaluated.
    2. In a second desktop study, IGS will quantify the impact of Iowa’s large flood-control reservoirs (Red Rock, Saylorville, and Coralville) on riverine N and P loads. Mass balance results will be used to evaluate opportunities to increase nutrient loss occurring in large reservoirs.
  3. In addition to IGS-led field projects, IGS scientists will provide geological services to other INRC-supported research as requested, including for monitoring well installations, geophysics and groundwater monitoring.