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OPTIMAL WELL LOCATOR (OWL): A SCREENING TOOL FOR EVALUATING LOCATIONS OF MONITORING WELLS: USER'S GUIDE VERSION 1.2
Citation:
Srinivasan, P., D. F. Pope, AND E. STRIZ. OPTIMAL WELL LOCATOR (OWL): A SCREENING TOOL FOR EVALUATING LOCATIONS OF MONITORING WELLS: USER'S GUIDE VERSION 1.2. U.S. Environmental Protection Agency, Washington, DC, 600/C-04/017, 2004.
Impact/Purpose:
screening tool to evaluate and optimize the placement of wells in long term monitoring networks at small sites
Description:
The Optimal Well Locator ( OWL) program was designed and developed by USEPA to be a screening tool to evaluate and optimize the placement of wells in long term monitoring networks at small sites. The first objective of the OWL program is to allow the user to visualize the change in ground water flow direction and magnitude at a site over time. OWL uses typically available site data including routine ground water level measurements and well locations in a regression algorithm to produce a linear plane approximation of the ground water flow field. This approximation is then used to produce an individual linear contour map of the ground water potential for each measurement event date. By viewing the variation in the ground water flow direction and magnitude over time in these simple maps, users will be able to see and develop a greater understanding of the dynamic nature of ground water flow at their site. The second objective of the program is to allow the user to visualize the influence of the changes in ground water flow over time on plume migration at the site. OWL uses minimal contaminant plume characterization data in a simple contaminant migration algorithm to forecast the potential plume migration path for each approximate ground water flow field using a constant source and time period. OWL provides a separate plume concentration map for each ground water flow field to demonstrate to users how variations in ground water flow magnitude and direction can impact the movement of contaminants over the site. In addition, OWL combines all of the predicted plume migration paths into a composite plume concentration map. This map shows users the forecasted locations where the plume is likely to be present at their site. The third and final objective of OWL is to allow the user to use this information to assess the location of existing wells and to better position future wells. OWL performs this task by producing a map which combines the composite plume concentrations with a simple measure of monitoring well coverage into a Well Optimal Location Factor (WOLF). The WOLF map has two purposes. First, it will enable users to identify locations where the plume concentration is predicted to be high and the well density to be low. Such a spot would be an optimal location for a new well. Second, if plume concentration is forecast to be low and well density is high in an area, it will alert users that it may be possible to eliminate redundant existing wells. Unlike most modeling programs, OWL is specifically designed for users who have minimal ground water and contaminant modeling experience. Site managers can use OWL as a screening tool to evaluate their site monitoring well networks and potentially reduce monitoring costs by optimizing well performance.