Nature Conservancy Environmental Constraints for CA

Nature Conservancy environmental constraint data for CA: click here to download shapefile

The Nature Conservancy’s mission is to protect the lands and waters on which all life depends. Purchasing land for permanent protection is not the only way to protect the natural and agricultural resources that support our communities, economies, and biodiversity. Conservation-informed planning that avoids development in pristine habitats and in areas important for water supply or flood attenuation can lead to more sustainable growth while protecting the natural resources that communities depend upon.

Conservation-informed planning can be achieved both by minimizing and avoiding impacts. To minimize impacts, run the Conservation Module within UrbanSim for each scenario to evaluate and compare indicators across scenarios for water resources, climate change mitigation, agriculture, and habitat. To avoid impacts, set development constraints using the Nature Conservancy’s recommended constraints layer. This will help you build a scenario from the start that avoids placing development in areas with important natural resources such as:

  • Wetlands

  • Floodplains

  • Riparian areas

  • Areas with high groundwater recharge potential

  • Threatened and Endangered species habitat

  • Very intact habitats

  • Protected lands (public and private)

Avoiding development in these areas will support wildlife, attenuate flood risk for downstream municipalities, and provision clean water to farmers, ranchers, and urban and rural water users.

Though not included as development constraints in this provided layer, avoiding disturbance of lands that store and sequester carbon is also recommended as an important tool for climate mitigation to meet greenhouse gas reduction goals. Similarly, avoiding urbanization in farmland is important for supporting local agriculture.

Constraint Layer Methods

All constraint datasets were filtered to a defined threshold when applicable and were merged together (See table below). Already developed areas were then removed from the constraints layer. Areas considered developed and removed were classified as Low, Medium, or High Intensity development in the National Land Cover Data Set.

Constraint data sources and thresholds

Input Data

Constraint Thresholds

Source

Developed Lands

Filtered to Low, Medium, or High Intensity Developed lands.

[1]

Intact Lands

See Conservation Module Methods documentation.
Resistance surface filtered to <=1.4.

[2]

Threatened and Endangered Habitat (T&E):
Species California Wildlife Habitat Relationships
(CWHR) Range Maps

See Conservation Module Methods documentation.
Habitat suitability weighted richness for T&E species
was filtered to top 40%.

[3]

Threatened and Endangered Habitat (T&E):
Species - Wildlife Habitat Relationships
System (WHRTYPE) - Suitability lookup

See Conservation Module Methods documentation.
Habitat suitability weighted richness for T&E species
was filtered to top 40%.

[3]

Riparian areas

Filtered to natural stream and artificial path and
buffered to 150 meters.

[4]

Groundwater Recharge Potential

Stratified by hydrologic region and filtered to top 20% of
each hydrologic region.

[5]

Wetlands

[6]

Floodplains

Filtered to 100 year floodplain

[7]

Protected lands

[8]

References