2021-8-31_Spokane_CountyChad W. Coles, P.E. – Director / County Engineer
1026 West Broadway Avenue Spokane, WA 99260-0170
Phone: (509) 477-3600 Fax: (509) 477-7655 TDD: (509) 477-7133
www.spokanecounty.org
Lori Barlow, AICP, Senior Planner
City of Spokane Valley 10210 East Sprague Avenue, Spokane Valley, WA 99206
Dear Ms. Barlow,
Spokane County Public Works submits the following comments relative to Floodplain and Stormwater issues for the EIS for the proposed Painted Hills PRD:
1.Off-Site Proposal: We are concerned with the overall lack of detail and clarity on offsite
proposal in Spokane County and with addressing of the associated impacts. Suggest
maps/plans specifically to address the offsite areas. Also, the Biological Report and
Cultural Resource Survey do not appear to address off site project area at all.
2.CLOMR and Permitting Process: Spokane County requests that the CLOMR and
CLOMR-F package include all floodplain modifications, both in the City and the County.
Before County would sign off on the CLOMR application, we perform a detailed review
and accept project plans sets, engineering/geotech reports addressing infiltration and
floodplain hydraulic engineering, and a detailed Operation and Maintenance manual.
Spokane County Public Works will not approve or issue floodplain permits for work in
County until FEMA approves the CLOMR and CLOMR-F for the entire project and CSV
has approved the development. It’s not clear if this is proposed, but there needs to be an
alternative to infiltration testing beyond full scale construction of all the proposed
drywells in the Triangle Pond.
3.Triangle Pond /Gustin Ditch– Need to address use of Spokane County’s existing drainage
easement and current property owners needs for the Triangle Pond. This will require
project proponent to negotiate an agreement to purchase or obtain easement and
compensation for both. Also proposed plans cannot encumber County plans for
extension of 40th Ave. around the Triangle pond. Note as well that these need to be
addressed with letters of intent from property owners at a minimum before the County
can sign off the Community Acknowledgement for the CLOMR application.
4. Risk Analysis- This table needs more detail on potential failure impacts. A map to
address potential flooding would be helpful. This is critical for the Operations and
Maintenance manual and future maintenance efforts to insure potential failures and their
impacts are minimized.
5.Factors of Safety: Please clarify factor of safety for design flows in the stormwater
systems, both on and off site. We see different flow capacity for pipes and system in
different parts of the report and not sure its addressed at all for the off-site facilities.
Suggest a table of facilities with design flows and factors of safety.
August 31,2021
Chad W. Coles, P.E. – Director / County Engineer
1026 West Broadway Avenue Spokane, WA 99260-0170
Phone: (509) 477-3600 Fax: (509) 477-7655 TDD: (509) 477-7133
www.spokanecounty.org
6. HOA Maintenance: Spokane County has continuing concern with HOA being responsible
for maintenance, due to the uncertainty of their long term existence and capability to do
the critical work needed with this complex of a stormwater/flood control facilities. Need
stronger guarantee of ongoing maintenance for entire system, including facilities in
Spokane County. Note also, a proposed detailed Operations and Maintenance Manual for
the entire system and proposed implementation/organization plan will need to be
submitted before the County will sign the Community Acknowledgment for the CLOMR.
Thank you for the opportunity to comment. Sincerely,
Marianne Barrentine, PE, CFM Water & Environmental Program Manager