Elsie Gridley Mitigation Bank

The Elsie Gridley Mitigation Bank is the largest vernal pool mitigation bank in the State of California. It was established to provide offsite mitigation opportunities for vernal pool grassland and riparian habitats and several associated rare, threatened, and endangered species.

Wetland Resources, LLC received bank approval in 2006, and it has been amended twice. Three phases of vernal pool restoration were implemented, and a fourth and final vernal pool restoration phase is in planning. Wetland Resources, LLC hired RES to conduct the bank’s ecological monitoring, design, and implementation of future phases, compliance reporting, and credit sales.

The 1,815-acre Gridley Bank is located in rural Solano County, California, south of the City of Dixon and adjacent to the Solano Land Trust’s Jepson Prairie Preserve.

Numerous wetlands and vernal pools were preserved or restored within the property, along with habitat for special-status species, including California tiger salamander, vernal pool tadpole shrimp, vernal pool fairy shrimp, vernal pool conservancy shrimp, Swainson’s hawk, Delta green ground, Boggs Lake hedge hyssop, and others.

Key Bank Metrics

• 100 acres of Army Corps Section 404 mitigation credits currently constructed
• Additional 130 acres of Army Corps Section 404 mitigation credits in the design/planning phase
• Largest CTS conservation bank with over 1,500 acres of CTS upland and aquatic credits
• Riparian and linear stream credits, vernal pool crustaceans, burrowing owl, and Swainson’s hawk credits

Available Credit Types

Download service area maps and KMZ files below:

• Burrowing owl: Service area map | KMZ
• California tiger salamander: Service area map | KMZ
• Freshwater emergent marsh: Service area map | KMZ
• Seasonal wetland (404): Service area map | KMZ
• Swainson’s hawk: Service area map | KMZ
• Vernal pool conservancy, fairy, and tadpole shrimp: Service area map | KMZ
• Vernal pool (404): Service area map | KMZ

Tim DeGraff, RES VP and GM for West Region, led a tour in June 2023 at the request of several California regulators, accompanied by Elsie Gridley landowners Mike Gridley and Ben Winslow.

The site tour of Elsie Gridley was at the request of the Department of Water Resources (DWR), who also invited California Department of Fish and Wildlife (CDFW). A total of about 20 regulators walked the site, with Tim and others from RES providing an overview of the habitats and our site management activities.

The tour included walking through Elsie Gridley’s mixed habitats, with frequent stops where regulators could ask questions and get a deeper briefing.

The tour continued through Elsie Gridley’s mixed habitats.

The tour group gets a briefing from Tim and an opportunity to ask questions.

The 2023 superbloom season at Elsie Gridley was very dramatic. As this vernal pool dried, you could see concentric rings of various flower species around the vernal pools.

As spring progresses, another common flower to see blooming at Elsie Gridley is the Rosy Douglas’ Meadowfoam. This white flower with a red center dominates vernally wet meadows and vernal pool edges.

Broad leaf filaree (Erodium botrys) can also be found growing amongst the sea of butter n’ eggs at Elsie Gridley.

Rosy Douglas’ Meadowfoam (Limnanthes douglasii subsp. rosea) (large white flowers), yellow carpet (Blennosperma nanum) (light yellow), broad leaf filaree (Erodium botrys), butter n’ eggs (Triphysaria eriantha) (red-yellow flowers), stalked popcornflower (Plagiobothrys stipitatus var. micranthus) (very small white flower), all in bloom at Elsie Gridley.

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