Native Growth Protection Areas (NGPAs) and Critical Area Protection Areas (CAPAs)

What is a Protection Area?

A Native Growth Protection Area (NGPA), or Critical Area Protection Area (CAPA), is the Snohomish County Code designation for permanently protected property that contains a critical area, a critical area buffer or both. Critical areas include wetlands, lakes, streams, rivers, and geologically hazardous areas. Vegetated buffers around critical areas are important in preventing loss of the functions and values that these sensitive areas provide and to protect life and property. Development permitted under the Critical Area Ordinance prior to 2007 are referred to as Native Growth Protection Areas (NGPA), while development permitted under the Critical Area Ordinance after 2007 are Critical Area Protection Areas (CAPA). These apply to both multi-residence developments and single-lot developments.

The landowner(s) of the NGPA or CAPA, are responsible for protecting and preserving these critical areas and buffers. In most cases an NGPA/CAPA is part of a developed neighborhood or condominium building and it is the responsibility of the neighborhood homeowners or Homeowners Association (HOA) to manage and protect it, but these protections can also be found on single lot residences. In general, vegetation within the NGPA/CAPA cannot be disturbed. There are a few exceptions; contact your Snohomish County Watershed Steward for more information.

Landowner Technical Assistance

Snohomish County provides a variety of resources to help landowners and HOA’s manage their NGPA/CAPA. Surface Water Management offers a variety of technical assistance for NGPAs/CAPAs located within unincorporated areas of the county. Available resources include technical assistance, restoration guidance, educational workshops, print materials, and site visits customized to the needs of your NGPA/CAPA. All resources are designed to help improve water quality and wildlife habitat, and reduce other impacts such as flooding, erosion and pollution.

Start by contacting your Watershed Steward with your questions or to schedule a free site visit  (see "Contact Us").

Getting to  Know Your NGPA/CAPA

How Does a NGPA/CAPA Work?

Healthy and mature vegetation around critical areas provides important wildlife habitat and plays a natural and critical role in managing stormwater runoff. Some of the benefits that NGPAs/CAPAs provide include:
  • Reduced amounts of polluted stormwater runoff in our streams, lakes and wetlands
  • Improved flood capacity and reduced soil erosion
  • Habitat for fish and wildlife
  • Protection of property and public safety

Does My Neighborhood Have a NGPA/CAPA?

Your NGPA/CAPA is any land that has a stream, lake, wetland and/or a critical area buffer within it. Most NGPA/CAPA’s have signs along their perimeter. If you suspect you have an NGPA/CAPA in your neighborhood or on your property, but there are no signs, there are several documents where your NGPA/CAPA information is recorded. These documents include a development's plat map, a parcel's Critical Area Site Plan (CASP) or Official Site Plan. These documents can be searched for on the Snohomish County Auditor website. Your Watershed Steward can assist in looking up and reviewing any designated NGPA/CAPA within your plat or property.

(back to "Getting to know your NGPA/CAPA")

Is My NGPA/CAPA Healthy?

NGPA/CAPA’s typically represent a small fraction of our original natural environment and can be completely surrounded by development. Critical areas, like streams and wetlands, were once part of a vast network of natural forests and freshwater systems that covered Snohomish County. Though now a fragment of historic forests, your NGPA/CAPA can still provide highly productive and healthy habitats. Here are a few indicators of a healthy NGPA/CAPA:
  • Diverse native tree, shrub and groundcover species are present
  • Wildlife is present 
  • Decaying organic material (snags, leaf litter, fallen trees, etc.) from native trees and shrubs in the Protection Area
  • Little or no populations of invasive species 

How Can I Tell If My NGPA/CAPA Is Unhealthy?

Development, deforestation and other land uses have fragmented critical areas. Changes over time can result in an unhealthy NGPA/CAPA to the point where the area no longer functions properly for the purpose of pollutant reduction or habitat protection. Although not all are a violation of Snohomish County code, the following are indicators that your NGPA/CAPA may be unhealthy:
  • Invasive weed populations
  • Unhealthy or lack of diverse native vegetation
  • Encroachment on NGPA boundaries
  • Dumping of yard waste, garbage and/or pet waste


Can I Do to Protect My NGPA/CAPA?

If your NGPA/CAPA has any of the “symptoms” listed in the previous section, there are many options for improving its health. There are actions which you or your community can take to improve your NGPA/CAPA health and function. These include:
  • Identify and control invasive plant species 
  • Prevent yard encroachment on boundaries
  • Don’t dump garbage, pet waste or yard waste in NGPA/CAPA
  • Hire a certified arborist to assess tree health
  • Contact a Snohomish County Watershed Steward for a free site visit (see "Contact Us"
  • Create a Management Plan 
Additionally, here are easy actions you can take on your property to further protect the critical areas within your NGPA/CAPA:
  • Set up yard waste pickup to avoid adding yard waste to the NGPA/CAPA and to prevent the spread of weeds and disease 
  • Practice Natural Yard Care 
  • Avoid encroachment of your yard and landscape on the boundaries of the NGPA
  • Pick up pet waste and dispose of in the trash
  • Control invasive species on your property