192_-_2021-8-31_Gerard_NavarraFrom:ggn
To:Lori Barlow
Subject:Painted Hills PRD
Date:Tuesday, August 31, 2021 4:31:43 PM[EXTERNAL] This email originated outside the City of Spokane Valley. Always use caution when openingattachments or clicking links.
Hello Lori:
Below are comments in response to the DEIS for the proposed Painted Hills development adjacent
to Thorpe Road:
· Almost without exception, the common scenario for flooding around the golf course
property is high run-off over frozen subgrade. That implies that the proposed idealized
design is based on a circumstance that will rarely occur, ie proper bio-filtration before
injection into the aquifer. The most likely flood scenario managing mechanism for the
proposed system will be to dump large quantities of untreated water into the aquifer via the
over flow drains. This will be combined with a substantially increased pavement area when
project build-out is complete. A proper design must include substantial storage capacity to
provide a reasonable likelihood that the overflow mechanism will not be triggered.
Alternate 2A obviously does not accomplish that end. It is not clear that even 2B would
achieve this goal, since volume comparisons (current storage versus proposed) are not
indicated in the DEIS. Underground pipe storage should also be considered in the
developed areas to provide sufficient storage to avoid unfiltered injection and
contamination of the aquifer and local water wells. A phased build out would also be
prudent to verify the adequacy of the proposed system and leave options open for
additional storage to supplement the system in place of designated housing lots if it proves
deficient.
· The DEIS does not provide any grading plans with which to make comparisons of the
proposed versus existing adjacent property grades. In the likely event that clogging and icing
occurs in the overflow drains, what adjacent properties will be immediately affected and to
what degree? What are the proposed elevations of the new lots as compared to residential
units immediately adjacent to the PRD.
· A fund should be available to immediately put into place enhancements or repairs to the
flood control system should they prove inadequate. Flooding could occur before the HOA
payments have built to a sufficient level to provide more than minor maintenance.
· The presentation on the impact of truck traffic is inadequate. Firstly, truck traffic does
substantially more damage to road surfaces than automobile traffic, even though typically
making up only about 5% of ADT; therefore, downplaying it as 1% of ADT is intentionally
misleading. Truck induced damage to roadways is especially bad during thawing periods.
Secondly, transporting 30 CY of material requires the use of truck and trailer. If the more
likely scenario of single trucks are used, the average number of trucks entering the site
jumps to more than 40 per day or one every 11 minutes. That will be a wearingly high
intensity when considered over 4 years. These numbers will be even worse on “non-
average” days. The pavement damage is undeniable when considering over 25,000 truck
and trailer trips or 50,000 single truck trips. The developer must be held responsible for
some of these costs when issuing the grading permit, as opposed to the taxpayer. Here
again, alternative 2A appears unreasonable.
Thank you,
Gerard G. Navarra, P.E.
Spokane Valley, WA 99016
509-951-1405