Hamilton Street Bridge Site

Facility Site ID: 84461527 Cleanup Site ID: 3509

Multi-Family Residential Development Planned

One benefit of redevelopment will be reducing unauthorized access to the site, as evidenced by this hole cut in the security fencing
One benefit of redevelopment will be reducing unauthorized access to the site, as evidenced by this hole cut in the security fencing
We held a public comment period September 28 - October 27, 2020, for a Cleanup Action Plan (CAP) amendmentProspective Purchaser Consent Decree, and Scope of Work and Schedule for a multi-family residential development Sagamore Spokane, LLC is planning on a portion of the site.

The CAP amendment explains how the development will enhance the cleanup actions already in place, prevent contaminants from leaving the site during construction, and protect occupants of the new buildings. The Scope of Work and Schedule details engineering, construction, and operations and monitoring reporting requirements, and the schedule for completing these milestones.

Ecology held a public meeting October 14, 2020, (view the presentation), and we responded to two sets of comments. The draft documents were finalized with minor modifications to the CAP amendment to ensure new pilings don't adversely affect groundwater.

Site Background

Capped portion of the site, looking northeast
Capped portion of the site, looking northeast
The site is along the Spokane River under the Hamilton Street James E. Keefe Bridge. The site is made up of two adjacent properties, which housed the Spokane Manufactured Gas Plant and American Tar Company. We combined these two properties impacted by the business operations into the Hamilton Street Bridge site.

The Spokane Manufactured Gas Plant produced coal gas and carbureted water gas between approximately 1905 and 1948. The facility was used for mixing, storing, and distributing a propane-air system from 1948 to about 1956. In 1956, the company changed its name to Spokane Natural Gas Company and distributed natural gas from the facility. In 1958, Washington Water Power Company, now Avista Corporation, merged with the Spokane Natural Gas Company. Natural gas continued to be dispensed from the site until about 1963 when Richard Brown leased the property. In 1978, he purchased it, and in 1982 it was deeded to Spokane River Properties, of which he is a general partner.

The parties responsible for cleanup are Avista Corporation, BNSF Railway Company (BNSF), and Spokane River Properties, Limited.

Contamination

Monitoring wells and capped portion of the site, looking east
Monitoring wells and capped portion of the site, looking east
Contaminants in soil included volatile organic hydrocarbons (VOCs) and semivolatile organic hydrocarbons (sVOCs), polycyclic aromatic hydrocarbons (PAHs), and metals.

Groundwater samples taken from points surrounding the soil-contaminated area detected relatively few of these materials. Contaminants that were found leaching into the groundwater are undergoing biodegradation and attenuation through physical, chemical, and biological processes. 

Investigations show that the Spokane River is not being adversely impacted by the site.

Cleanup

Riverbank stabilization, looking east
Riverbank stabilization, looking east
From 1997 to 2006, the parties responsible for cleanup completed several cleanup actions. A compacted gravel surface serves as a cap that blocks human exposure pathways (ingestion, contact) to contaminated soils.
 
A restrictive covenant prohibits activities that might result in the release of contaminants. They also serve to ensure the long-term integrity of the cap over contaminated soil and the two building foundations that remain as caps over contamination.

When restrictive covenants are used, Ecology visits the site at least every five years. In 2010, Ecology completed the first periodic review and determined that the remedy was still protective of human health and the environment. The surface appears in acceptable condition, with no signs of excavation or other disturbance of the capped areas. No repair, maintenance, or further actions have been required. 

In 2015, Ecology completed the second periodic review and concluded that the cleanup actions completed at the site are protective of human health and the environment. Soil cleanup levels have not been met; however, the cleanup action does comply with standards, since the long-term integrity of the containment system is ensured, and the requirements for containment technologies have been met.

Total arsenic and dissolved arsenic were reported above cleanup levels during the March 2015 sampling event. Other recent sampling events have shown concentrations of arsenic, mercury, cyanide, and PAHs that exceed state standards. Fluctuations of contaminants above state standards, particularly in wells adjacent to the Spokane River, should be further evaluated to determine if they are impacting the Spokane River.

For more information, see the Technical Reports section of the document repository.

Site use restrictions called institutional controls are in effect

Institutional controls can be fences, signs, or restrictions on how the property is used. For instance, an institutional control may prohibit installing drinking water wells or disturbing a protective cap that isolates contamination. These restrictions keep the contamination contained and keep people from being exposed to the contamination. The controls are usually listed in environmental covenants recorded with the county.

Periodic reviews are required when institutional controls are required at a site. Ecology conducts reviews to make sure the controls remain effective and the cleanup still protects human health and the environment. We conduct periodic reviews about every five years.

Environmental Covenant

County Recording #: 6839202
County Recording Date: 7/24/2019

Covenant Restrictions

  • Control Stormwater
  • Ongoing Maintenance of Remedy
  • Prevent the Reuse or Relocation of Site Soil
  • Prohibit New Building Construction
  • Prohibit Soil Disturbance
  • Restrict All Ground Water Extraction/Well Installation
  • Restrict Domestic Ground Water Extraction/Well Installation
  • Restrict Land Use

Media Restrictions

  • Groundwater
  • Soil

Environmental Covenant

County Recording #: N/A
County Recording Date: 9/9/2004

Covenant Restrictions

  • Control Stormwater
  • No on-Site storage of chemicals.
  • Prevent the Reuse or Relocation of Site Soil
  • Prohibit New Building Construction
  • Prohibit Soil Disturbance
  • Restrict All Ground Water Extraction/Well Installation
  • Restrict Domestic Ground Water Extraction/Well Installation
  • Restrict Land Use

Media Restrictions

  • Groundwater
  • Soil

Environmental Covenant

County Recording #: N/A
County Recording Date: 1/29/2003

Covenant Restrictions

  • Control Stormwater
  • No on-Site storage of chemicals
  • Prevent the Reuse or Relocation of Site Soil
  • Prohibit New Building Construction
  • Prohibit Soil Disturbance
  • Restrict All Ground Water Extraction/Well Installation
  • Restrict Domestic Ground Water Extraction/Well Installation
  • Restrict Land Use

Media Restrictions

  • Groundwater
  • Soil
Legal 8
Document Title Document Date Document Type
Prospective Purchaser Consent Decree for Sagamore: Hamilton Street Bridge Site 1/5/2021 Consent Decree
Memorandum of Understanding re. City Project Work on the Site 6/14/2016 Interlocal/Interagency Agreement; Memorandum of Agreement or Understanding
Adverse Impact from City Construction Work 5/29/2014 Interlocal/Interagency Agreement; Memorandum of Agreement or Understanding
Restrictive Covenant 9/9/2004 Environmental Covenant; Alternative Mechanism
Hamilton Street Bridge EO Remedial Action 7/13/2004 Enforcement Order
Hamilton Street Bridge EO Remedial Action 7/13/2004 Enforcement Order
Hamilton Street Bridge - Consent Decree 9/12/2002 Consent Decree
Hamilton Street Bridge AO Remedial Action Avista Corporation BNSF Railway Co. 3/7/2000 Agreed Order
Public Information 7
State Environmental Policy Act 1
Document Title Document Date Document Type
Hamilton Street Bridge SEPA Determination of Non-Significance (DNS) 12/1/2002 SEPA Documents
Technical Reports 24
Document Title Document Date Document Type
Engineering Design Report: Hamilton Street Bridge/Sagamore development 4/26/2022 Engineering Design Report
Approval of Cleanup Action Implementation, Addendum 1, Engineering design Report 6/1/2021 Site Specific Administrative Document - other (Administrative correspondence)
Scope of Work and Schedule: Hamilton St. Bridge CAP Amendment 1/5/2021 Scope Of Work
Cleanup Action Plan Amendment: Sagamore Development Hamilton Street Bridge Site 1/5/2021 Cleanup Action Plan
2nd semi-annual groundwater report, 2019 12/10/2019 Groundwater Monitoring Report
2019 Annual Site Inspection Report 11/22/2019 Site Specific Technical Document - other
Restrictive Covenant for Spokane City Parcel No. 9/5/2019 Site Specific Administrative Document - other (Administrative correspondence)
Request to enter into a Prospective Purchaser Consent decree 8/15/2019 Site Specific Administrative Document - other (Administrative correspondence)
1st Semi-annual Compliance Groundwater Monitoring Rpt. 2019 6/5/2019 Groundwater Monitoring Report
2018 Annual Operations & Maintenance Site Inspection: Hamilton Street Bridge 1/3/2019 Performance/Confirmational Monitoring Plan or Report
Groundwater Compliance Sampling: Chlorine and Sulfide Screening 6/26/2018 Site Specific Technical Document - other
Letter to the City of Spokane: MLK Jr. Phase 2B Stormwater plan 2/12/2018 Site Specific Administrative Document - other (Administrative correspondence)
Semi-annual GW Monitoring Report 2nd Event 2017 12/19/2017 Groundwater Monitoring Report
Change of Ecology Site Coordinator 9/14/2017 Site Specific Administrative Document - other (Administrative correspondence)
Semi-annual GW Monitoring Report, 1st Event 2017 7/31/2017 Groundwater Monitoring Report
Second Periodic Review: Hamilton Street Bridge 12/3/2015 Periodic Review (5 Year)
Periodic Review: Hamilton Street Bridge 8/27/2010 Periodic Review (5 Year)
Cleanup Action Completion Report 2/2/2006 Final Cleanup Action Report
Operation and Maintenance Plan 1/8/2004 Operation and Maintenance Plan
Engineering Design Report 9/28/2003 Engineering Design Report
Institutional Control Plan 5/29/2003 Site Specific Administrative Document - other (Administrative correspondence)
Compliance Monitoring Plan 5/28/2003 Performance/Confirmational Monitoring Plan or Report
Final Cleanup Action Plan 8/10/2001 Cleanup Action Plan
HAMILTON STREET BRIDGE SITE Site Hazard Assessment 8/1/1998 Site Hazard Assessment Report
There may be more documents related to this site. To obtain documents not available electronically, you will need to make a public records request.

Places to see print documents

  • Eastern Regional Office
    N 4601 Monroe St
    Spokane, 99205-1265
    Please schedule an appointment to view print documents at this location.

Contaminants 2

Contaminant Type
Soil
Groundwater
Surface Water
Air
Sediment
Bedrock
Non-Halogenated Organics - Polycyclic Aromatic Hydrocarbons RA RA
Metals - Arsenic C
S
Suspected
C
Confirmed Above Cleanup Levels
B
Below Cleanup Levels
RA
Remediated-Above
RB
Remediated-Below
R
Remediated
This contaminant list was based on our best information at the time it was entered. It may not reflect current conditions at the site.