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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Hydrology and Remote Sensing Laboratory » Research » Research Project #435242

Research Project: Age-dating Stream Waters for Selected CEAP NIFA Competitive Watershed Studies using Chiral Metolachlor Ethane Sulfonic Acid (MESA)

Location: Hydrology and Remote Sensing Laboratory

Project Number: 8042-13610-029-44-I
Project Type: Interagency Reimbursable Agreement

Start Date: Aug 15, 2018
End Date: Aug 14, 2019

Objective:
Our overall objective is to characterize the MRT for agricultural watersheds across different drainage conditions (e.g., well drained, karst hydrology, ditch drained and tile drained). Specifically: 1) Implement chiral MESA measurements to “age date” stream waters at the outlets of nine NIFA watersheds in regions with significant corn/soybean production. 2) For a subset of the NIFA watersheds a nested watershed sampling design will be implemented to assess the relationship between watershed size (HUC level) and MRT. The watersheds selected for this aspect will include those in which we have strong cooperation with local researchers.

Approach:
Objective 1: Passive integrative sampling devises (POCIS samplers) will be placed at the outflow of each watershed and where possible co-located at USGS gage stations for flow measurements. Monthly, 4-week integrative samples will be recovered over the course of one year. Objective 2: Select three of the watersheds to implement a nested sampling design to study the influence of the scale of observation on MRT determinations. Depending on watershed characteristics, the design of this study could involve up to 4 scales of observation. The selection of three CEAP watersheds to be involved in this aspect of the study will depend on the degree that local support can be provided for sample collection and perhaps sample processing required for analyses.