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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 />

Water Quality BMPs and BMP Maintenance<br />

Impact HYDRO-3 (page 4.3-36 through 4.2-47) details the proposed stormwater treatment<br />

systems for Alternatives A, B, C, D and E. Alternatives A, B and E will capture, convey and<br />

infiltrate the 20yr/1hr storm total runoff volume, while Alternatives C and D will capture, convey<br />

and infiltrate up to the 100yr/1hr storm total runoff volume. For Alternatives C and D, the<br />

stormwater treatment system schematic is illustrated in Figures 4.3-1, 4.3-2 and 4.3-3. For<br />

Alternatives A, B and E, the stormwater treatment system is described on pages 4.3-36 and 4.2-<br />

37. Design Plans for the BMP Retrofit for Existing Conditions (Alternatives A, B and E) was<br />

first submitted to TRPA in August 2007 and referenced in the DEIS as Appendix P. These design<br />

plans were updated and resubmitted based on comments and questions received during the DEIS<br />

comment period and are provided as supplemental information for DEIS Appendix P in Appendix<br />

AB. Under all Alternatives, runoff from the TRPA 20yr/1hr design storm (i.e. the current<br />

regulatory requirement) will not leave the project area untreated or enter into NDOT ROWs.<br />

Under Alternatives C and D, runoff volumes from up to the 100yr/1hr storm event will not leave<br />

the project area untreated or enter into NDOT ROWs except possibly under very extreme<br />

antecedent soil moisture conditions.<br />

Long-term performance of any stormwater treatment system is reliant on the operations and<br />

maintenance of the system. The loss of efficiency over time will be minimized through proper<br />

operations and maintenance as determined in the inspection, operations and maintenance plan<br />

required for permitting of the selected Alternative. The supplemental analysis does consider the<br />

loss of gallery efficiency due to antecedent moisture in the system. The Inspection, Maintenance<br />

and Monitoring Plan is a standard practice of the Project (added as SP-10 in Chapter 6). The Plan<br />

will be developed for the selected Alternative through an RFP Process that includes a third party<br />

agreement between TRPA, Boulder Bay and a consultant. This detailed plan will be based on<br />

Chapter 6 of the EIS but can be tailored to the outcome of the Governing Board hearings that will<br />

decide the final design of the Project, if approved.<br />

Because some of the facilities are subsurface, access points are built into the linear treatment<br />

system for maintenance and monitoring. The costs associated with maintenance and monitoring<br />

will be determined during project permitting because these costs are directly related to the<br />

selected Alternative. Subsurface infiltration galleries and other Low Impact Development (LID)<br />

strategies including pervious pavers and rain water harvesting are in regular use at Lake <strong>Tahoe</strong><br />

and have recently been installed in a number of public works projects including but not limited to:<br />

Lake <strong>Tahoe</strong> Unified School District (High School), City of South Lake <strong>Tahoe</strong> (Lakeview<br />

Commons), State of California (Department of General Services - <strong>Tahoe</strong> Base Center), and Placer<br />

County DPW (<strong>Tahoe</strong> City Transit Center). Although Boulder Bay will be required to properly<br />

maintain stormwater treatment systems as a condition of project permitting, the DEIS<br />

recommends mitigation measure HYDRO-1 to assure that stormwater treatment systems are<br />

operated and maintained to be effective in meeting TRPA discharge standards. The post project<br />

monitoring program will be finalized in accordance with the permitting conditions for the<br />

selected Alternative and will most likely include some level of stormwater monitoring in addition<br />

to BMP and stormwater treatment system inspections.<br />

Master Response 2 – Traffic Baseline<br />

Comment Summary – The traffic baseline used for the analysis does not accurately reflect current<br />

conditions or future vehicle miles traveled. The actual existing traffic counts should be used instead of a<br />

theoretical assumption of traffic levels when the existing facility is operating at full capacity.<br />

PAGE 8- 16 HAUGE BRUECK ASSOCIATES SEPTEMBER 8 , 2010

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