Corridor-Level Environmental Site Assessment - City of Port Orchard

MOSQUITO FLEET TRAIL PROJECT • Port Orchard, Washington
General Corridor-Specific Contamination
The Corridor is located in a commercial and residential area. There is the potential to encounter
contamination in the soil and groundwater due to the use of petroleum hydrocarbons and/or dry
cleaning solvents from past use of these materials in the area.
The western portion of the Corridor was filled between 1965 and 1980 based on the geologic map,
Sanborn maps and aerial photographs. The source of the fill is unknown and may contain
contaminated soils.
We understand several houses on the east end of the Corridor will be directly impacted by
construction activities in the Corridor. The Kitsap County Assessors website indicates the
residences were built between the 1910s and 1950s with heating systems listed as forced air.
Heating oil storage tanks can be associated with residences and commercial structures of this age
and type of heating. We understand the houses will not be demolished but that minor grading and
sidewalk construction is planned for the Corridor in this area. Managing potential contamination
associated with heating oil tanks will likely be the responsibility of the City of Port Orchard.
Blackjack Creek crosses the central portion of the Corridor. The Creek receives stormwater from
areas that contain undeveloped, residential and commercial properties. There is the potential for
low concentrations of contaminants to be present in stormwater runoff.
Contamination from heating oil tanks and stormwater runoff are all considered low environmental
concerns with respect to the project.
CONCLUSIONS AND RECOMMENDATIONS
Six properties were identified as environmental sites of concern. ROW acquisition is planned
where the proposed alignment is located adjacent to an existing City of Port Orchard ROW. The City
of Port Orchard plans to acquire easements where the proposed alignment is not located adjacent
to existing ROW. Risks of encountering contamination were evaluated based on readily available
information and this report does not constitute a Phase I ESA per ASTM International (ASTM) 1527-
05. Four low-risk sites, two moderate-risk sites and no high-risk sites were identified during our
study. A brief description of each site is outlined in Table 1. The locations of the sites are shown in
Figures 3 through 7.
Our recommendations for further action to mitigate potential impacts are as follows:
■ ROW acquisition is planned as part of the project within Sites 1 and 6. A Phase I ESA per ASTM
Standard E 1527-05 on Sites 1 and 6 prior to ROW acquisition is recommended. A Phase II
ESA including subsurface investigation may be recommended based on the findings of the
Phase I ESA.
■ Contaminated media, hazardous wastes and/or USTs encountered during construction
activities should be managed in accordance with environmental regulations. The bid
documents should require the earthwork contractor and other personnel that could potentially
contact contaminated materials comply with training requirements for handling contaminated
May 23, 2011 | Page 7
File No. 12309-009-00