Developer outlines sewer, stormwater plan for Hermanson Preserve; staff stresses permitting needs

Sewer and stormwater infrastructure were a recurring technical topic during the June 25 hearing on Hermanson Preserve (SUB 25‑02).

Senior planner Dan Handel said serving the site with sanitary sewer is a primary obstacle because existing city lines are too shallow to serve the whole property, so the applicant proposes a new public sewer line paired with the Greenway/Deer Run roadway and an offline connection that would be brought from a pump station near Mill Creek Meadows. Handel noted substantial permitting and cost implications for crossing the riparian corridor.

Applicant representative Jamie Venakthimal described alternatives considered and said the chosen alignment is the least impactful. Venakthimal also described a stormwater detention pond designed to detain and treat runoff for the subdivision and to reroute an existing self‑storage facility’s pipe into the new pond rather than allowing direct discharge to the creek. ‘‘Our proposed storm drain outlet is actually downstream of the pond,’’ the applicant said, noting emergency overflows can interact but the outlet location reduces direct impacts to Hermanson Pond.

Commissioners asked whether the sewer work would disrupt existing service; the applicant said the new line is an offline system and the existing 32‑ft deep main would not be removed, though construction crossings and temporary activity are expected. The approved conditions require the applicant to coordinate permitting (DSL, DEQ, Army Corps) and to implement design measures that mitigate wetland impacts and protect water quality before discharge.