FAQ
Questions on Hamilton project Mar 08
What are wetlands and why are they important?
What kinds of plants and animals live in the wetlands?
What are dredged materials and why are they being used?
Who are the project’s main supporters?
What can I do to help protect the functions and values of wetlands in the U.S.?
How will the restored wetlands benefit the environment?
How will the restored wetlands benefit the community?
How do wetlands affect the local climate?
How can wetlands affect global warming?
Are there any disadvantages to restoring the wetlands?
Why are you restoring the wetlands now?
Who is paying for the restoration?
Are there any risks to using dredged materials?
Is there any contamination left over from the Hamilton Army Airfield?

Q: What are wetlands and why are they important?
A: A wetland is a lowland area, such as a marsh or swamp, that is typically found under a wide range of “wet” conditions. At least some of the time, a portion of the wetlands’ soil is saturated by water, resulting in the maintenance of moist soil.
Wetlands are known as transition zones where the flow of water, the cycling of nutrients and the energy of the sun meet to produce a unique ecosystem characterized by moist soil and lush vegetation. They are often referred to as “nurseries of life” because they provide habitat for many of the area’s vibrant and endangered species as well as other migratory animals that may pass through the land over time.
The Hamilton Wetlands Restoration Project site is mostly composed of intertidal wetlands, or emergent marsh habitat and mudflats that are exposed during low tides. Subtidal wetlands, aquatic habitats that are never exposed during low tide and grassland communities, also makeup the Hamilton Wetlands Restoration Project site.
Restoration of these tidal wetlands provides a rare opportunity to offset historic habitat losses. Through the ongoing and current restoration project, many acres of tidal marsh, seasonal wetlands, transitional and upland habitat will be restored to its natural state, reestablishing important ecological functions in the San Francisco Bay Estuary.
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Q: What kinds of plants and animals live in the wetlands?
A: The Hamilton Wetlands Restoration Project site includes two main types of habitats for its plants and animals: subtidal and intertidal habitats. Subtidal habitats are never exposed during low tide, and intertidal habitats are emergent marsh habitat and mudflats that are exposed during low tides.
Species that occupy the subtidal aquatic habitats of the project site include all different types of plankton, or small plant and animal organisms that float or drift in groups in fresh and salt water. Various plankton at the Hamilton Wetlands Project site include different algae, floating plants, corals, sea anemones and jellyfish. Fish such as longfin smelt, northern anchovy and speckled sanddab as well as worms and clams can also be found at the site or in the sandy, muddy bottom of the Bay. Additionally, many different species of waterfowl and diving birds use the subtidal aquatic habitats for feeding areas.
The intertidal mudflats at the Hamilton Wetlands Restoration Project site are highly productive and support large populations of worms, crustaceans and mollusks. When exposed or covered by shallow water, the mudflats provide important foraging grounds for migrant and wintering shorebirds, wading birds and gulls. The coastal salt marsh lands of the intertidal aquatic habitats are dominated by cordgrass and pickleweed. This vegetation provides direct cover for adult fish such as longfin smelt, chinook salmon and steelhead to spawn. The coastal salt marsh lands also provide nesting, foraging and escape cover for various songbirds and wading birds.
The table below offers some additional information regarding special status species observed at the project site.
Common and Latin Name |
Status |
Habitat |
California clapper rail
(Rallus longirostris obsoletus) |
State and federal endangered |
Cordgrass marsh, tidal sloughs |
California black rail
(Laterallus jamicensis coturniculus) |
State threatened |
Pickleweed marsh and grasses at edge of marsh |
San Pablo song sparrow
(Melospiza melodia sammuelis) |
State species of special concern |
Tidal marsh |
Salt marsh common yellowthroat
(Geothlypis trichas sinuosa) |
State species of special concern |
Salt marsh and fresh water emergent marsh |
Northern harrier
(Circus cyaneus) |
State species of special concern |
Marshes and grasslands for foraging |
Short-eared owl
(Asio flammeus) |
State species of special concern |
Marshes and grasslands for foraging |
Burrowing owl
(Spermophilus beecheyi) |
State species of special concern |
Grassland with ground squirrel burrows |
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Q: What are dredged materials and why are they being used?
A: Dredged materials are sediments at the bottom of harbors and other waterways that are suctioned up by large machinery. Several hundred million cubic yards of sediment must be dredged from different U.S. ports, harbors and waterways each year in order to maintain and improve the nation’s navigation system for commercial, national defense and recreational purposes. In a typical year, the U.S. Army Corps of Engineers must dredge about seven million cubic yards of sediment to maintain safe navigation in and around the San Francisco Bay. In order to effectively manage these large amounts of dredged sediment, the San Francisco Bay Long Term Management Strategy for Dredging was established as the “Regional Dredging Team” for the San Francisco area. The LTMS ensures that the dredged materials are being used in mutually beneficial situations, according to the national dredging policy set forth by the federal government.
Historically speaking, dredged materials have been used to both restore existing wetlands and establish new ones. Together, the LTMS, has determined that the usage of dredged materials in the restoration of the Hamilton Wetlands benefits both the source of the dredged sediments, the Port of Oakland, as well as the wetland site. Financially, the process of dredging benefits the public by speeding up the project by at least four years and saving the project more than $25 million in costs.
To learn more about the LTMS or to view the 2001 LTMS Management Plan, click here.
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Q: Who are the project’s main supporters?
A: The Hamilton Wetlands Restoration Project is a joint venture between the U.S. Army Corps of Engineers, the State Coastal Conservancy and the San Francisco Bay Conservation and Development Commission. Additionally, the project enjoys broad support from various environmental groups, labor and maritime interests, as well as from local government. This includes: the City of Novato, the County of Marin, the San Francisco Bay Joint Venture, The Bay Institute, Ducks Unlimited, Save SF Bay Association, the National Audubon Society, the U.S. Fish and Wildlife Service, the Nation Marine Fisheries Service and the U.S. Geological Survey.
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Q: What can I do to help protect the functions and values of wetlands in the U.S.?
A: The United States loses about 60,000 acres of wetlands each year. And, although the Environmental Protection Agency is working with other government agencies and organizations including the U.S. Army Corps of Engineers to reverse this trend, there are many things that private residents can do to help. Here are a few simple guidelines to follow if you’d like to help prevent wetland loss or degradation:
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Invest in wetlands by buying duck stamps. Proceeds from these $15 migratory bird hunting stamps support wetland acquisition and restoration. The stamps are available at the U.S. Fish and Wildlife Service’s Web site, http://www.fws.gov/duckstamps.
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When developing your landscaping plan, keep wetlands in mind. Plant native grasses or forested buffer strips along wetlands on your property to protect water quality.
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Support your local watershed association the nearest to the Hamilton Wetlands Restoration Project is the North Bay Watershed Association. You can visit the organization’s Web site at http://www.nbwatershed.org.
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Plan a wetland program or invite a wetland expert to speak at your school, club, youth group or professional organization. You can request that someone from the Hamilton Wetlands Restoration Project team make a presentation at your next event by contacting Maria Or at Maria.Or@spd02.usace.army.mil.
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Q: How will the restored wetlands benefit the environment?
A: Wetlands provide numerous ecological services that benefit the environment. Some of these services include:
Re-creating native wildlife habitats Critical habitat destruction is a major issue in preserving species and preventing their endangerment. Restoring wetlands reestablishes the native habitats that are crucial to preserving wildlife and endangered species like the California Clapper Rail and the Salt Marsh Harvest Mouse.
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Water purification Wetlands are extremely effective at absorbing nutrients, contaminants, and pollutants, as well as controlling soil erosion, before runoff enters our rivers, lakes and streams.
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Soil replenishment and erosion control Areas covered by plants, rather than pavement, absorb the energy from rainfall and stabilize the existing soil in its place. The plants, small animals and microscopic organisms also replenish and enrich the existing soil.
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Fish propagation and repopulation Small and deeper pools of water are an integral part of wetland habitats. By restoring these pools, fish and its food sources naturally replenish and repopulate areas that once were barren.
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Maintenance of natural cycles Wetlands promote the maintenance of several biological cycles, including the hydrologic, oxygen and nitrogen cycles, by absorbing and storing water and replenishing oxygen into the atmosphere through photosynthesis. Wetlands also prevent the buildup of harmful compounds of nitrogen, like ammonium.
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Pest management Wetlands contain a wide variety of insect predators, which significantly contributes to the control of pests.
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Q: How will the restored wetlands benefit the community?
A: Restored wetlands offer many social and economic benefits to the local community. Wetlands provide an area of scenic and natural beauty that many enjoy for recreational purposes. They are also able to reduce property damage from flooding by absorbing the energy from severe weather conditions.
It has been estimated by biologists that just one acre of wetlands provides over $100,000 per year in services. For example, the natural water purification function provides the local community with a no-cost water treatment plant. Also, there are many very expensive projects being implemented throughout the nation to reintroduce fish populations for sport and commercial fishing interests. The fish propagation capacity of a wetland achieves this at minimal cost.
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Q: How do wetlands affect the local climate?
A: Because plants absorb the radiation from the sun and release water vapor through their respiration process, wetlands naturally maintain an even climate by keeping the surrounding area cool in the warm months and moderate in the cooler months.
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Q: How can wetlands affect global warming?
A: We have heard a lot recently about global warming and the dangers of rising levels of carbon dioxide in the atmosphere. Wetlands play a significant function in reducing levels of carbon dioxide by absorbing it from the atmosphere and serving as a “sink,” or storage area, for carbon in the soil.
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Q: Are there any disadvantages to restoring the wetlands?
A: Some nearby residents or visitors to wetlands have noticed an unpleasant odor. This is a byproduct of the naturally-occurring water purification and nutrient absorption process. However, the social, economic and environmental benefits of wetlands far outweigh any disadvantages.
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Q: Why are you restoring the wetlands now?
A: In 1994, the Hamilton Airfield Base was officially closed under the Base Realignment and Closure Act, often known as BRAC. As part of the base closure process and under federal environmental law, [Comprehensive Environmental Response, Compensation and Liability Act, or CERCLA] the U.S. Army is responsible for the remediation (cleanup) of their former base to protect human health and the environment and restore it to natural conditions.
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Q: Who is paying for the restoration?
A: The Hamilton Wetlands Restoration Project is funded by the State of California, the State Coastal Conservancy and the federal government.
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Q: Are there any risks to using dredged materials?
A: All dredged sediment will be extensively tested prior to the placement at the site for contaminants at levels that would be harmful to any wetland species or humans. Once tested, the materials will be pumped to the project site through a pipe from barges docked approximately five miles away, offshore of China Camp. The entire filling process for the Hamilton Wetlands will take approximately six years to complete.
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Q: Is there any contamination left over from the Hamilton Army Airfield?
A: In 2001, the Army undertook several cleanup actions and investigations to meet its obligations under the Comprehensive Environmental Response, Compensation and Liability Act before the property could be transferred the State Coastal Conservancy During these investigations, several contaminants left over from when the base was a functioning airfield were found. These contaminants include petroleum, heavy metals, polychlorinated biphenyls (PCBs) and pesticides. The Army also identified the presence of low levels of dichlorodiphenyltrichloroethane, commonly known as DDT, a potent pesticide, which has been shown to significantly impact birds and is now illegal in the U.S. The plan to cleanup the remaining sites of contamination is underway and the plan is detailed in the Remedial Action Plan. Cleanup is funded by the Department of Defense’s Base Realignment and Closure (BRAC) program at no-cost to the Hamilton Wetland Restoration project.
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Hamilton Wetlands Project Questions: March 2008
- Why bulldozing ALL night long? (Why not restrict this noisy part of the process to 0700 – 2000 or other “reasonable timeframe?)
Response: The most cost effective and efficient operation of the offloader requires that material be delivered to the site 24 hours a day, and spreading the material out away from the discharge end of the pipeline is required. However, in order to be good neighbors, we will endeavor to restrict the noise to a reasonable timeframe. The contractor is currently reviewing the noise levels and we will be changing the current construction techniques so as not to create a disturbance at night. No heavy equipment will operate between the hours 10:00 PM and 7:00 AM.
- Do the lights need to be on all night? (waste of energy / sleep… these bright lights go right through our blinds and keep us up at night)
Response: The lights are for the safety of the personnel working out on the job. We are also looking at our construction techniques with a view towards mitigating the impacts to housing areas.
- Will the lights be moved southward (closer to Bayside housing area) as the project progresses?
Response: Yes, however we anticipate that the activities closer to the housing area will not be of long duration. We will also endeavor to take all reasonable means to conclude the activities in that area as soon as possible.
- How much dredge material (how high?) will end up on the airstrip?
Response: The amount of material placed on the airstrip will vary from one end to the other, but will range from a few feet to as much as 5 feet above the current runway elevation. The highest elevation in the seasonal wetland will be about 5 feet below the NHP Levee.
- Will the entire enclosed area north & east of Bayside be filled-in, or will the little “seasonal wetlands pond” (northeast corner) be preserved?
Response: Yes, it will be filled in and reshape as a “Seasonal wetland area”.
- Where will the Pacheco Creek/storm drain/rain runoff go? (It used to drain along reservoir hill and into the “seasonal wetlands pond”, but the drain piping was sealed a few months back)
Response: The drain at the northwest corner of the site that was closed off so that dredging process water would not flow out of the Hamilton Army Airfield. This pipe did not convey water from Pacheco Creek, but only from a small area around Landfill 26. Army BRAC is currently working on a plan to install a pump station to convey this water onto the Hamilton Army Airfield.
- How long until dredge fill material is down to Bayside pump station exit point? (this is right behind my house).
Response: Dredge fill will probably be in that area in about a month. We shouldn’t be placing there for any longer than one month. We will continue to adjust our construction techniques to try and mitigate any disturbance.
- How long to fill in the entire area north of the hangars?
Response: This is variable, however if we are able to work at the most efficient and expeditious rate, we anticipate that it will take about 2-3 months.
- When will area just east (south of the midline east-west levee) of the hangars be filled in?
Response: This placement timeline is not confirmed to date, however should the Oakland project receive adequate funds in the next fiscal year, it is estimated to be around Dec 08-Jan 09 timeframe.
- What is plan for the southern area “tidal wetlands” and where will the south end storm drains dump into bay?
Response: The southern area will be seasonal wetlands. Water from the existing storm water pumps will flow through a channel in the seasonal wetland and out to the bay through the tidal wetland.
- When will entire wetlands area be filled in?
Response: The current best estimate for project completion is around 2015 at which time we will breach the Marsh plain levee and will monitor our success for about 13 years to 2028.
- Will the antenna field area that was excavated be filled in with dredge material?
Response: Yes. We don’t have the date yet.
- Does dredge piping run all the way from Oakland Channel dredge?
Response: No, the dredged material in the Oakland Harbor is picked up and loaded into scows/barges and towed to a location 5 miles off shore at Hamilton. From there it is offloaded using a converted hydraulic dredge (the offloader) and a series of pumps to get the material on site.
- Does the giant booster pump run all the time? (how much HP?)
Response: No, only when there is a Scow/Barge being offloaded. This operation rate varies depending on traffic at Oakland, material type being dredged, and multiple other variables. The time running is usually between 6-16 hours/day. The land booster pump that I think you are referring to is a 3500HP pump, which can pump at a rate of 21,000 gallons per minute. However it is usually operating at 17,000 GPM.
- When can we go out on the southern perimeter levee to get to Las Gallinas Trail (that heads south towards the Las Gallinas Valley Sanitary District reclamation ponds…. Great for walking the dog, cycling, etc)?
Response: Because of both operational and safety concerns, we don’t have a firm schedule for this at this time.
- Will there be trails on the levee that borders the bay (for bicycling/bird watching, etc)?
Response: The Bay front levee at Hamilton will be non-existent when the project is complete. There will be no public access to that area as it will be endangered species habitat. Our trail will terminate in a viewing platform 700 feet away from the outboard marsh. The existing informal access to the bay front levee to the south will still exist once the levee work is complete. Check the Hamilton website for update of public access, http://www.hamiltonwetlands.org/index.php and other links.
- Does the Army Corps of Engineers work with Rails-to-Trails Conservancy?
(or Marin Bicycle Coalition) on trail plans?
Response: No, we aren't near any Railroad easement. We coordinated only with local residents and the Bay Trail Coalition.
- When/Where will the Bay Area Trail continue north into Bell Marin Keys?
Response: At this time no final decision has been made. Pursuant to the NEPA/ CEQA process we are studying several options. These include the junction of Pacheco Pond and the N-1 levee.
- Can elevated Hawk nesting boxes be installed at the end of the project?
Response: We plan to coordinate with the Bay Institute on a variety of volunteer projects for Hamilton residents and others to participate in. While at this point we have not explored the possibility of installing hawk nesting boxes on the project, we shall consider that as an option. We have however, already considered owl, bat and swallow boxes as potential ideas. They would make a fun project. We plan to place these in areas deemed appropriate by the FWS.
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