FEIS - Tahoe Regional Planning Agency
FEIS - Tahoe Regional Planning Agency
FEIS - Tahoe Regional Planning Agency
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RESPONSE TO COMMENTS ON THE DEIS<br />
B o u l d e r B a y C o m m u n i t y E n h a n c e m e n t P r o g r a m P r o j e c t E I S<br />
ROWs as described in responses to comments 337a and 337b) contribution to runoff<br />
that enters Caltrans drainage systems down gradient to effectively 0 cfs for the<br />
20yr/1hr design storm. Alternatives C and D reduce contributions from the project<br />
area to effectively 0 cfs for the 100yr/1hr storm. Runoff from portions of NDOT<br />
ROWs that are not within the project area could continue to contribute to "pass<br />
through discharge" and enter Caltrans systems, however, but is outside the scope of<br />
the Project. The comment that NDOT agreed to coordinate with the Project to<br />
address interstate flow concerns during the December 5, 2008 meeting is noted.<br />
Comment 337-d: Comment Summary - The existing 18-inch drainage pipe east of Stateline is<br />
inadequate, and NDOT and Boulder Bay agreed (12/08) that it should be replaced by<br />
a larger pipe to accommodate 100-year storm runoff from the entire tributary area<br />
and not just Boulder Bay.<br />
The comment that the existing capped 18-inch pipe under SR 28 would not<br />
accommodate the anticipated 100yr/1hr discharge from the tributary watershed under<br />
existing conditions is noted and is correct. The commenter fails to recognize the<br />
effective removal of this runoff volume under Alternatives C and D, however, which<br />
could negate the need to replace the existing 18-inch pipe. Under Alternatives A, B<br />
and E, only the 20yr/1hr storm volume would be captured and removed from the total<br />
runoff volume and the replacement of the existing pipe could be necessary.<br />
Comment 337-e: Comment Summary - Collection and infiltration of impervious surface runoff does<br />
not fully address the total tributary runoff that contributes to highway drainage.<br />
The stormwater drainage systems are designed to capture, convey and infiltrate<br />
runoff from total contributing areas, including impervious and pervious areas within<br />
the project area and Washoe and NDOT roadways and ROWs included in the project<br />
area and a portion of those up gradient from the project area that contribute runoff to<br />
the project area. See Tables 4.3-5 through 4.3-12 for summaries of total contributing<br />
pervious areas and DEIS Appendix G for the detailed contributing areas. Table 1 is<br />
added in Appendix AB that provides a summary impervious areas/land coverage in<br />
combination with the LID strategies and the associated effective coverage reductions<br />
incorporated into Alternatives C and D, including green roofs, pervious pavers and<br />
bioretention for stormwater filtration systems.<br />
Comment 337-f: Comment Summary - Page 4.3-1 and 2: Project is located in a smaller watershed<br />
than "East Stateline Point watershed tributary area." Provide the actual size of this<br />
smaller watershed and quantify in DEIS.<br />
The East Stateline Watershed is a TRPA priority watershed and is discussed in the<br />
existing conditions because the DEIS is a TRPA decision document. The smaller<br />
subwatershed discussed in the comment was delineated by DRI for the Brockway<br />
Project Area Stormwater Runoff and Characterization Study (Hayvaert et al. 2008)<br />
and Lumos and Associates delineated the contributing watershed areas for the<br />
Boulder Bay project area during the planning and design of the stormwater treatment<br />
systems for the Project. The "brockway" subwatershed is approximately 167.3 acres<br />
as delineated by DRI. Note that this subwatershed area included only half (8.6<br />
acres) of the Boulder Bay project area. Given that the total project area is 16.26<br />
acres, the project area comprises less that 10% of this subwatershed.<br />
Comment 337-g: Comment Summary - Impervious surface runoff may be insignificant compared to<br />
total watershed runoff as discussed in NOP comment letter (8/8/08). Total runoff<br />
may impact highway drainage systems, not just impervious runoff.<br />
SEPTEMBER 8 , 2010 HAUGE BRUECK ASSOCIATES PAGE 8- 153