Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/15/2004
Publication Date: 11/15/2004
Citation: McCarty, G.W., Angier, J. 2004. Temporal variance of stream nitrate flux in a first-order stream under base flow conditions [abstract]. American Society of Agronomy. Paper No. 5808. 2004 CDROM.
Technical Abstract: Non-point source pollution of surface waters is difficult to control with some pollutants, such as nitrate, being delivered primarily through groundwater. Riparian buffer ecosystems have the potential to remove contaminants from groundwater and to reduce movement of nitrate into surface water. Many riparian zone models assume uniform groundwater flow through such ecosystems leading to effective removal of groundwater nitrate. However, in a small first-order stream in the mid-Atlantic coastal plain, baseflow generation was highly variable. Specific areas of the stream consistently received greater amounts of high nitrate groundwater than others. Areas with the floodplain responsible for most of the nitrate exported from the watershed are termed critical areas. Over a five year period of monitoring, about 50% of the total exported nitrate originated from less than 10% of the total riparian ecosystem. Total annual stream nitrate loads were 5 times greater during a high precipitation year than in dry years. Allocation of resources to address non-point pollution should focus improving mitigation function of critical areas with riparian ecosystems.