Using Spatial and Remote Sensing Technologies to Help Interpret Results from Monitoring Studies and Support Stewardship Initiatives
In the October 2003 Atrazine Interim Reregistration Eligibility Decision (IRED), the US EPA required a statistically designed multiple season intensive monitoring program to measure atrazine concentrations in small headwater streams flowing through highly vulnerable watersheds. 40 watersheds (9-100 sq. mi.) were instrumented and monitored for at least two seasons between 2004 and 2006. Atrazine concentrations were measured at least every 4 days at all sites along with flow and weather data. Detailed GIS data were accumulated and analyzed in order to identify potential drivers of runoff in each watershed. Of these 40 potentially highly vulnerable watersheds, only 3 were determined by EPA to require continued monitoring and a watershed management program based upon the monitoring results. Two of these three streams exhibit intermittent flow during the summer. Monitoring continued after 2007 in these three as well as several adjacent watersheds using a daily auto-sampling protocol.
Hendley P., R. Joseph, C.Harbourt and P. Miller. Using Spatial and Remote Sensing Technologies to Help Interpret Results from Monitoring Studies and Support Stewardship Initiatives. Land Grant and Sea Grant National Water Conference, Washington, DC. Jan. 31-Feb. 1, 2011.
Higher Tier Modelling of Groundwater Concentrations from Pesticides Used on Rice
The Med-Rice model is used to determine Predicted Environmental Concentrations in groundwater (PECgw) for pesticides used on rice. Higher tier approaches have not been established under EU guidance to address situations when the Med-Rice model generates a PECgw greater than 0.1 ug/L. This poster compares several options for conducting higher tier modelling of PECgw by linking the RICEWQ (a pesticide fate and transport model developed to simulate the seepage, flooding conditions, overflow, and controlled releases of water associated with rice production) with several leaching and/or groundwater models including VADOFT (Vadose Zone Flow and Transport model) and HYDRUS-1D (unsaturated flow and solute transport model).