New Site Location and Assessment

There are three requirements for site location of a P removal structure:

1. Elevated dissolved P concentrations in runoff.  I have found that it is generally not worthwhile unless the dissolved P concentrations are > 0.25 ppm.
2.  Hydraulic connectivity.  In other words, the runoff produced at the site must have the potential to reach a surface water body; otherwise there is not really a problem.
3.  Potential to channel the runoff water into a single point for treatment.  Sometimes this is already completed for you if there is a drainage ditch, culvert, subsurface drainage outlet, etc.  Otherwise, you have to physically alter the flow so that it will converge into a single point.

The P removal structure will be constructed on a poultry farm located in Eastern OK.  The producer volunteered the site; he is an excellent cooperator and a progressive steward.  At the location, there are several poultry houses in a small 9-acre sub-watershed.  Poultry litter spillage often occurs near the entrance to the house and as a result of the connective hydrology at the site, P can potentially be transported to a nearby creek, which is located within the Illinois River Watershed.  Based on a site survey and visual observations during rainfall-runoff events, the following potential location within the site was chosen for the P removal structure:

The proposed site is located on the side of hill.  Starting in September, 2012, “grab” samples of runoff were taken during runoff events for analysis of dissolved P.  This is especially critical for the obvious reason that construction of a P removal structure is not justified if there is not sufficient runoff dissolved P!  This is why we initially refer to this site as a “potential” location because we did not know if it was a good candidate until we started taking some samples. It turned out that the dissolved P tested in the runoff samples ranged from 1 to 2 ppm.  Due to the elevated P concentrations, the site hydraulic connectivity, and the potential to channel water to a single point for treatment, this site becomes a perfect location for constructing a P removal structure!