Summary of Significant Comments Received/Issues Raised on the July 3, 2001 Working Draft Bay Criteria and Tidal Water Designated Uses During the First Round of Review (July 3rd -September 3rd, 2001) Overall Score Card Tidal water designated uses: 90 comments received; 21 pages of responses Dissolved oxygen criteria: 61 comments received; 24 pages of responses Water clarity criteria:75 comments received; 29 pages of responses Chlorophyll criteria: 104 comments received; 40 pages of responses General comments: 41 comments received; 11 pages of responses Grand Total: 371 comments received; 125 pages of responses Tidal Water Designated Uses S Description of designated uses more in terms of habitats than actual human oriented uses S Definition of the use of the term "balanced indigenous population" S Delineation of the vertical boundaries between open water, deep water and deep channel S Delineation of the horizontal boundaries of where to apply open water/deep water/deep channel vs. open water/deep water vs. open water all the way to the bottom with emphasis on the southern mainstem Chesapeake Bay S Delineation of the seasonal anoxic region and how to best account for this natural occurrence (expanded given human presence in the watershed) within the context of the deep channel use S The level of detail to be included in the designated use appendix to the EPA published Bay criteria document vs. the more detailed delineations of designated use locations the states will be going out with in their draft criteria/uses adoption package S Adoption of use as subcategories under existing designated uses S How will the adopted designated uses influence the application of existing state water quality standards' criteria (e.g., salinity based criteria application) Dissolved Oxygen Criteria S Decision to drop 4 non-Chesapeake Bay species from the low dissolved oxygen effects data base used to derive the Bay specific dissolved oxygen criteria S Use of instantaneous minimum as the temporal application period for criterion values under all five sets of designated use specific criteria S More explicit documentation of uncertainties and cases where conservation assumptions were made in the criteria derivation process S Criteria attainment procedures for addressing criterion values with temporal averaging periods less than one month (4 mg/L weekly; 3.5 mg/L instantaneous minimum, etc.) S Accounting for naturally low/no oxygen conditions in determining criteria attainment S Factoring in considerations of attainability into criteria derivation S Recalculation of the EPA freshwater criteria to reflect only tidal fresh Bay resident species S Application of the larval recruitment model on a species specific basis incorporating spatial segmentation of the designated uses ------- S Extensive changes to the existing Bay monitoring program are needed to fully support determination of the dissolved oxygen criteria attainment Water Clarity Criteria S Expanded details on the methodology for determining the criteria application depth and weight given the historical photography-based depths of SAV beds from the 1930s-1960s S Concern over indirect measure of water clarity criteria S Need for further validation of PLL values generated by the algorithm with the distribution of SAV in the Bay and tidal tributaries S Proposal that the criteria be applied as guidelines on a "trial" basis S Underestimation of SAV survival depth in tidal fresh and oligohaline habitats S Overestimation of epiphytic biomass S Request for ability to derive site specific modifications of the Bay criteria based on more extensive regional/local data to refine the PLL algorithm S Changes to the monitoring program needed to address concerns about extrapolation of mid- channel data to characterize nearshore water quality conditions Chlorophyll a criteria S Lack of statistically significant difference between chlorophyll a status in the "reference condition" form that in non-reference conditions S No statement of the water quality/ecological goal that will be addressed by adopting baywide chlorophyll a criteria S No discussion of how the proposed chlorophyll a criteria will result in a significant ecological benefit that can not be achieved through the dissolved oxygen and/or water clarity criteria S Chlorophyll a criteria must be derived in a manner consistent with section 304(a) of the Clean Water Act S Need to state the water quality impairments being addressed by the chlorophyll a criteria and derive the chlorophyll a criterion values from a quantitative relationship between chlorophyll a concentration and measurements of the impairment S Showing different water quality categories have different phytoplankton characteristics and different average chlorophyll a concentrations does not demonstrate chlorophyll a is a useful predictor of these plankton characteristics S Use of the multiple lines of evidence approach in deriving/supporting derived criteria caused confusion-which role did it play S How will naturally elevated chlorophyll a concentrations in poorly flesh systems be accounted for in the determination of criteria attainment S Exactly how chlorophyll a criteria attainment will be determined given highly variable nature Implementation S Will criteria attainment be determined using monitoring data, model simulated outputs or a combination of both? ------- ------- |