Nutrient Criteria Stakeholders Meeting
June 20, 2006
USGS Environmental Research Center
Columbia, MO

In Attendance: Bob Bacon, ERC; Dorris Bender, City of Independence; Robert Brundage, Newman, Comley, and Ruth; Cindy Distefano, MDC; Peter Goode, Washington University; Ted Heisel, Washington University; Dan Obrecht, UMC; Mark Osborn, MDNR; Caitlyn Peel, HBA of St Louis; Mark Seip, HDR, Kansas City; Tony Thorpe, LMVP/UMC; John Waitman, City of Springfield; Gary Welker, EPA Region VII; Bob Williamson, City of Kansas City

Drinking Water Reservoirs: Tony distributed a handout with graphs that displayed mean total phosphorus and mean chlorophyll concentrations in Plains region lakes as a function of mean depth, as well as mean total phosphorus and mean chlorophyll concentrations as a function of flushing index. Points in the graphs that represented lakes used as drinking water sources were darkened. The distribution of the darkened points was roughly equivalent to the total distribution of points within the graphs. There were many points indicating drinking water lakes with high concentrations of phosphorus and particularly chlorophyll.

Tony’s conclusion from this was that drinking water reservoirs probably should not be treated differently from other reservoirs in terms of regulation of their nutrient loading. Dan expressed doubt that impairment of drinking water can be clearly defined by numerical nutrient criteria. Mark suggested that risk of impairment can be linked to nutrient loading. Gary argued that it has been established that there is increased risk to drinking water supplies associated with higher chlorophyll levels in the source water. Mark said he would consult with DNR’s drinking water program to see if there have been issues raised concerning those particular lakes identified as having higher chlorophyll levels.

Criteria Matrix and Rationale: Mark distributed the latest draft of the criteria matrix and the rationale. There were few changes from previous drafts. The 10 μg/L chlorophyll threshold was shifted from the action to the advisory column, and a 20 μg/L limit was placed in the action column. The listing of classified lakes in the ecoregional and flushing rate categories had been made more substantially complete.

There was some discussion of how trophic status would be managed for lakes in the Ozark region. Mark explained that the goal was to protect the lower trophic status (oligotrophic and mesotrophic) for those lakes that are known to be in that condition and protect all lakes in the region from hyper-eutrophy. Dan suggested that the rationale for that approach could be simplified. Rather than back calculating off of Carlson’s Trophic State Index, Jones 1993 publication could be cited to identify the threshold values. Input from people acquainted with the region, particularly fisheries biologists from MDC, is desired, and Cindy has been making some inquiries. Comments on some of the lakes have already been sent out to the group.

Benchmarks for development of rule: The deadline for sending a proposed rule to the Clean Water Commission has been extended to December 13, 2006. In order to complete the project for lakes and reservoirs by then the group identified the following tasks which need to be accomplished (not necessarily in this order):

• Fiscal notes, regulatory impact report.
• Literature search to support the rationale. (Cindy, Dan, and Terry volunteered.)
• Accounting for spatial variation in large lakes, Table Rock in particular.
• Decide how to regulate lakes in the Big River Region. Some appear to be more wetland than lake.
• Implementation procedures.
• Identification of desired trophic status for Ozark streams. Resolve conflicting targets for aquatic life support and whole body contact.
• Compile questions to address designated uses of lakes.
• Completion of matrix and drafting of rule.
• Collection of data from other sources beside Jones et al. e.g. Army Corps of Engineers. (Cindy volunteered.)

Next meeting: July 18, 1:00, Elm St Conference Center, Jefferson City