Error propagation and uncertainty in predicting nonpoint-source nitrate contamination in groundwater

• Main Author: ZiZi Angelica Searles
• Other Authors: Jason J. Gurdak, Leonard Sklar, Don Hodge
• Format: Master Thesis
• Language: English
• Published: San Francisco State University 2014
• Subjects: North Atlantic
• Online Access: http://hdl.handle.net/10211.3/132828

Nitrate (NO3-) is a regulated chemical that often comes from nonpoint sources (NPS) and threatens human health in concentrations above 10 mg/L as Nitrogen (N). To protect groundwater quality from NPS NO3- contamination, resource managers need to understand the source, transport, and attenuation factors that control NO3" in groundwater and have tools that predict its occurrence and extent at the aquifer scale. Groundwater vulnerability models and maps are promising tools that incorporate knowledge of controlling factors and can be used to make predictions of NO3- impacted groundwater. To improve the utility and accuracy of such tools, this research will quantify the sources and propagation of errors in recently (2012) developed vulnerability models and maps for the Basin and Range (BR), Central Valley (CV), Coastal Lowlands (CL), and North Atlantic Coastal Plain (NACP) Principal Aquifers (PA) of the United States. The errors identified will be propagated through the PA vulnerability models using Latin Hypercube Sampling (LHS) and the resulting uncertainty in model predictions will be illustrated.