Urbanization and Forest Change
This indicator describes changes in land use that include loss of forest land, as well as increase in urbanization and accompanying impervious surface cover. Patterns of land use and land cover are one of the driving forces behind overall ecosystem health.

How does this affect me?

Changes in land use from a natural forested or vegetated state to urbanized areas can lead to considerable changes in local conditions over time. These changes include:

Heat Island Effect

Buildings and impervious surfaces such as pavement are non-reflective and absorb heat. This raises the near-surface air temperature which in turn increases the cost associated with cooling.

Flooding and Increased Rate, or Velocity of Polluted Runoff

Polluted runoff moves quickly across impervious surfaces into the nearest freshwater stream, rather than absorbing into soils, wetlands and other natural landscapes. Rapid stormwater increases the velocity of streams, making them wider, wilder and stripping away valuable fish habitat. This fish/salmon habitat includes the small ripples, rocks and uneven bottom surfaces that fish eggs need to grow. Eliminating these spaces reduces the number of fish that survive to adulthood, which reduces sport fishing revenues, commercial fishing revenues and food for Orcas, a major tourism attraction. Increased velocity also increases flooding, resulting in damage to homes and other forms of personal property.

Toxic and Persistent Chemicals in Freshwater Systems

Increases in impervious surfaces increase the amount of chemicals, oils and other residues which end up in the human food chain. They can also lead to impaired freshwater quality that is cleaned up at considerable taxpayer expense. Many of these chemicals attach themselves to the stream bottom (sediment) and to the fatty tissue of fish and other animals. Persistent bioaccumulative and toxic chemicals (PBTs) build up with each successive eater in the food chain. In most cases, we are seeing contamination that lasts for over 30 years even if the chemical has stopped being used. Polychlorinated biphenyls, or PCBs, as well as flame retardants (polybrominated diphenyl ethers, or PBDEs) are some examples.

Pathogens and Bacteria in Freshwater Systems

Increases in impervious surfaces also increase the amount of bacteria and pathogens associated with the fecal waste from wild and domestic animals as well as humans. Some of these can cause illness in humans from swimming and eating from a contaminated freshwater stream. If serious enough, giardia, hepatitis or other illnesses can occur.

Reduction in the Quantity of Water

Impervious surfaces interrupt the natural cycle in which drinking water is replenished, or put back into underground aquifer and groundwater systems. This leads to decreases in the amount of water available for human use such as drinking, livestock watering, irrigation, manufacturing and recreation. Stripping streams of shading vegetation also increases water temperature, affecting fish health and reproduction.

Splitting (Fragmentation) of Wildlife Habitat

Spread out development patterns disrupt wildlife habitat by breaking it into small pieces that do not support protection from predators, reproduction, taking care of offspring and food sources. This in turn decreases biodiversity which contains the services referenced above. Since Washington State is fifth in the nation for wildlife viewing revenues, losing wildlife habitat translates into potential revenue loss for rural communities. The same holds for true for BC whose nature based tourism industry generates $2 billion each year.

Loss of Farms and Forestlands

Farms and forests are economically and environmentally productive land types, indelibly tied to our local and regional cultural heritage. Farms provide a stunning visual landscape, revenue, employment and more localized food distribution systems. Smaller farm and forestry operations represent multi-generational traditions, many artisan in nature, which provide both a sense of place as well as niche marketing opportunities. The loss of these land types means lost economic productive capacity, wildlife habitat (which itself is a revenue source) and increased infrastructure costs. Larger forestlands provide intact landscapes that can maintain habitat continuity.³

Urbanization as a Source of Shellfish Degradation

The coastline has become an increasingly attractive place to live, with 85 percent of the 12-county Puget Sound population living within 10 miles or 16 kilometers of the shores of Puget Sound.⁴ Increased urbanization has accentuated impacts in coastal shellfish harvest because the growing areas are just meters from the developed land. Stormwater runoff reaching these areas does not receive any pretreatment before entering the estuaries. Notably, this runoff contains fecal coliform (warm-blooded animal waste) that shellfish accumulate. Advanced studies from North and South Carolina indicate that shellfish growing areas can be affected when as little as five percent of the watershed is developed.⁵

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