EPA Comments on Draft Mid-Yakima River Basin Bacteria TMDL
1. Executive Summary
On p. xv, please revise the statement that "interested parties should consider complying with the irrigation season allocations first" so that it is clear to the reader thi...↓
2. Impairments Addressed by the TMDL
Table 5 lists the impaired waterbodies covered by this bacteria TMDL and states they are extracted from the most recent 303(d) list EPA approved, which EPA refers to as the "2012 list" while Ecology refers to it in this TMDL as the "2014 list." Under EPA's TMDL regulations, these impaired waterbodies must be associated with a Load Allocation. Load allocations are provided in the Draft TMDL's Tables 46-48. However, the following waterbodies listed in Table 5 are not found in those Allocation Tables:
74270 (Drainage Improvement District #24),
74271 (Drainage Improvement District #40),
74276 (Unnamed Ditch � Trib. to Moxee Drain),
45081 (Drainage Improvement District #48), and
45313 (Trib. to Moxee Drain)
Please revise the Load Allocation tables to include these five additional impaired waterbodies, so the bacteria TMDL is clear that LAs have been developed for each of the Table 5 impaired waterbodies that will, when implemented, result in attainment of WQS for bacteria.
3. Seasonal Variation and Load Allocations
On page 81 the bacteria load is described as being the greatest during the months of May through November and the dates for the irrigation season are described as April 15 � October 15. Pages 73-74 discuss that the greatest bacteria pollution occurs during May through October and also that the three tributaries were found to have excessive bacteria concentrations throughout the entire year. In addition, on page 85, the irrigation return stream flows are noted to occur April through October. Please be clear in the TMDL which specific dates apply to the Load Allocations assigned to each of the sub-basins and explain if the irrigation season months and days may vary for each sub-watershed. It will be important for interested stakeholders and the public to understand the temporal extent of impairments, load allocations, and the seasonal variation in load allocations.
4. Point Source Waste Load Allocations
Table 45 lists all the permitted facilities and their Waste Load Allocations. However, a large dairy mentioned in the analysis of potential point sources (page 10) is not listed in the table with their permit number. Please add an explanation that it is covered by a general permit for Confined Animal Feeding Operations for dairies that is administered by the Washington Department of Agriculture that requires dairies to meet the applicable water quality standard, and that Washington Department of Agriculture is responsible for ensuring compliance with the permit.
5. Margin of Safety
We encourage Ecology to review the list of factors supporting an implicit Margin of Safety and include only those factors which are most significant in that rationale.
Minor comments:
p. 73 � Please revise the sentence to read, "In fact, more than 60% of human infectious diseases, are caused by pathogens, such as E. coli. (Karesh et al., 2012)" We note that E. coli itself is not a disease.
p. 79, p. 88 and p. 89 � The TMDL is described as a "10-year TMDL" and this concept is not explained anywhere that we can find, nor is a reference cited (i.e., if this concept relates to a standard Ecology policy or implementation timeline for the TMDL). As written, it might be misinterpreted as a date on which the TMDL is no longer valid.
↓
