Sediment and Nutrient Trap Efficiency of a Small Flood-Detention Reservoir1
- D. L. Rausch and
- J. D. Schreiber2
Significant amounts of sediment and nutrients are removed from storm runoff by small flood-detention reservoirs such as Callahan Reservoir in central Missouri, which stores 1 cm of runoff from its 1,460-ha drainage area. The purpose of this study was to compare the trap efficiencies of sediment and nutrients and determine which factors affect them. During a 3-year study, this reservoir trapped an average of 85% of the incoming sediment, 77% of the total sediment phosphorus (P), and 37% of the inorganic nitrogen (N). Sediment leaving the reservoir was clay and contained about 23% of the inflowing total sediment P. Sediment and P trap efficiencies (TE) for individual storms were related to concentrations of sediment and P (solution and sediment) in runoff, respectively.
Average TE of total solution P (35%) was slightly lower than the TE of NO3-N (40%). Annual TE of ortho-P ranged from 8 to 64% and averaged 43%.
Dissolved organic and hydrolyzable P yields were greater in outflow than in inflow. These increases, which were <1% of the total P budget, may have been due to biological activity in the reservoir.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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