Surface flow off agricultural and urban areas contains elevated concentrations of inorganic and organic chemicals compared to subsurface soil waters. Due to weather conditions during the fall of 2008, record snowfall in December of 2008, and a recent blizzard event (March 2009), the National Weather Service is predicting that the water level of the Red River of the North (RR) in the cities of Fargo, ND and Moorhead, MN may reach 12.5 m above the river bottom, which would surpass the current record of 12.2 m set on 7 April 1897. The major flood level for Fargo is 9.1 m. Therefore, the purpose of this RAPID proposal is to quantify the effects of agricultural and urban runoff on water and soil quality upstream and downstream of a major urban area of North Dakota (Cities of Fargo) and Minnesota (City of Moorhead), which are located along the banks of the Red River of the North. The urgency for this grant is due to the fact that the RR water levels have only just started to increase in depth and the predicted maximum flood stage will be reached in late March, 2009. This event is being classified as a 500 yr flood with the predicted hydrograph showing flooding for only 20 to 30 d. This research will test two hypotheses: 1) that flooding-water quality will be impacted by the movement of this water through a large, urban environment; and 2) that post-flooding sediment deposited onto riparian and urban landscapes will have elevated chemical concentrations compared to the underlying soil. Hypothesis 1 will be evaluated by taking water samples upstream and downstream of the major population centers of Fargo-Moorhead and samples will be analyzed for 17â-estradiol (E2) and estrone (E1), total Hg, total gasoline hydrocarbons, total diesel hydrocarbons, nitrate, ammonium, phosphate, pH, electrical conductivity, sulfate, chloride, and total suspended solids. Hypothesis 2 will be evaluated by sampling three low lying areas that were flooded for more than 14 d, which will include a natural riparian area, a community garden or a public park, and an urban lawn. Deposited mass sediment will be determined and the sediment and underlying soil will be quantified for 17â-estradiol (E2) and estrone (E1), total Hg, total gasoline hydrocarbons, total diesel hydrocarbons, nitrate, ammonium, phosphate, pH, electrical conductivity, sulfate, and chloride.
The intellectual merit of the proposed research includes an expansion of the knowledge of how flooding-waters from and through both rural landscapes and urban centers influence both water and sediment quality. This work will increase our understanding of how flooding-water quality is impacted as it travels through an urban center of the northern Great Plains and also how the deposited sediment impacts soil quality. Many of the low lying areas within Fargo-Moorhead are used for parks, community gardens, and lawns and providing information about the quality of the post-flood sediment is important to scientific and public communities.
Floods are naturally occurring, but the origin of the flooding waters can influence water quality and the quality of soil in low lying areas. The broader impacts of the proposed research include a better understanding of the impact that major floods have on large, urban communities with respect to water quality and the quality of the deposited sediment. Training of a graduate student and disseminating the findings of this research to both public and scientific communities via presentations and published articles will be a primary focus of this research. Local and state officials will be particularly interested in the findings of this work.
