23194-GEOTECH-MEMO-2024-8-83
Convergent Energy and Power
7 Times Square I Suite 3504 I New York, NY 10036
M: 360.941.4134
convergentep.com
From: Scott Riegel <scottr@esnw.com>
Sent: Thursday, August 8, 2024 7:17 AM
To: Brandon Summers <bsummers@convergentep.com>
Cc: John Neer <johnn@esnw.com>
Subject: Re: PSE Site Work ES-9923/9924
Hi Brandon,
We completed fieldwork on both Rochester and Yelm sites and are proceeding with lab testing and report
preparation. Below is a quick summary of conditions encountered at each site.
ES-9923 Rochester, WA
Soil conditions were explored at 8 locations. Soils consisted of topsoil about 6 - 10 inches thick that
transitioned to recessional outwash sand and gravel layers. Maximum depth was controlled largely by caving
of the cohesionless soils to a depth of 10 feet below existing grade and no groundwater was observed. Soils
are suitable for conventional foundations. Infiltration testing was completed within the undisturbed outwash
soils and we measured rates of 134.7 iph (constant) and 129 iph (falling) at the first location and at the second
location, we measured rates of 58.7 iph (constant) and 50.5 iph (falling). These are unfactored rates and a
preliminary design infiltration rate of 20 in/hr may be used for screening purposes.
ES-9924 Yelm, WA
Soil conditions were explored at 8 locations. Soils consisted of topsoil about 6 - 10 inches thick that transitioned to recessional
outwash sand and gravel layers. Maximum depth was controlled largely by caving of the cohesionless soils to a depth of eight feet
below existing grade and no groundwater was observed. Soils are suitable for conventional foundations. Infiltration testing was
completed within the undisturbed outwash soils and measured rates of 194.3 iph (constant) and 257.2 iph (falling) at
the first location and we measured rates of 71.6 iph (constant) and 60.9 iph (falling) at the second
location. These are unfactored rates and a preliminary design infiltration rate of 24 in/hr may be used for
screening purposes.
Hope this helps and let us know if you need additional information from the design team while we work on
the reports.
Thank you,
Scott Riegel, L.G., L.E.G.
Associate Principal Geologist
Earth Solutions NW, LLC
Puget Sound/Western WA: 15365 NE 90th St, Ste 100 • Redmond, WA 98052 • P (425) 449-4704
Tri-Cities/Eastern WA: 3130 Varney Ln, Ste 105 • Pasco, WA 99301 • P (509) 905-0275
scottr@esnw.com • C (206) 793-9044
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