Model Remedies for former orchards

A cap is a barrier that prevents exposure to contaminated soil. This barrier can be hard, like asphalt, or it can be soft, like soil, grass or gravel. The cap must be maintained over time and any future property owner must be notified about maintaining the cap.

This option is generally the most cost effective.

Consolidate and cap

Contaminated soil is excavated from portions of a property and consolidated on the same property below a protective cap. Contaminated soils can be consolidated under permanent surfaces such as asphalt or buildings, or they may be placed in excavated holes or above-ground mounds covered by an engineered clean soil cap.

This is an excellent option for larger developments with space to create a consolidation area. For example, at an apartment building, you might be able to contain all the contaminated soil under the asphalt parking lot.

Mixing

For this remedy, contaminated soil is mixed with deeper, clean soil or imported clean soil. This option is not suitable for soils with high-levels of contamination. The remedy can easily fail if areas of elevated concentrations are missed, so proper sampling is important. To use this remedy there must be enough clean soil available, either on-site or imported, to successfully mix contaminated soil to concentrations below state cleanup levels. Any soil used must be sampled to ensure it's not contaminated.

After implementing a model remedy

Provide these forms to Ecology:

• Self-certification
• Subdivision certification

You can email them to FormerOrchards@ecy.wa.gov or mail them to our Central Regional Office, attention: Rhonda Luke.

It's important to let new owners know about the contamination and cleanup. Here's an example notification you can modify.