LAGUNA DE SANTA ROSA

The 'Laguna de Santa Rosa' is a fourteen mile (22.5 km) long wetland complex that drains a 254-square mile (658-square kilometer) watershed encompassing most of the Santa Rosa Plain in Sonoma County, California, USA.

Contents

Description

History

Geology

Hydrology and water quality

Ecology

Stewardship & Land Management

See also

References

External links

Description

The Laguna, whose principal tributary streams rise on the southern slopes of the Sonoma and Mayacamas Mountains,^[1] is the largest tributary of the Russian River. The sinuous watercourse is a significant floodplain during the heavy winter rains, capable of storing over 80,000 acre feet (99,000,000 m³) of stormwater.
Beyond its hydrological significance, the Laguna is Sonoma County's richest area of wildlife habitat, and the most biologically diverse part of the county, having been called a "national treasure" for its ecological wealth.^[2] A number of rare and endangered species occur in the Laguna, including federally listed threatened and endangered anadromous salmonid species and three endangered plants that are endemic here. From about 1870 to 1990 water quality and biota deteriorated in the Laguna, due to intensification of urban development^[3] and associated agricultural encroachment into the floodplain. In the 1990s the trend began to reverse, but the watercourse is still listed as Impaired under the federal Clean Water Act for sediment, nitrogen, phosphorus, temperature, mercury, and dissolved oxygen, rendering it the most impaired water body on the North Coast of California.^[4] Notwithstanding the large historical reduction in resource extent, the Laguna de Santa Rosa is presently the second largest freshwater wetland in Northern California and still habitat to over 200 species of birds, threatened and endangered salmonid species, bald and golden eagle, osprey, mountain lion, river otter, coyote, bobcat, mink and gray fox.
While the Laguna has been heavily impacted by human activities in its watershed over the past century, in recent years a movement has grown to preserve and restore it both for ecological functions such as habitat values and flood control capacity, and for outdoor recreation, education and research. The nonprofit Laguna de Santa Rosa Foundation, founded in 1989, has professionalized and expanded the scope of its programs since 2002, spearheading efforts to protect, restore, and create opportunities for the public to enjoy and learn in the Laguna.

History

Archaeological data illustrates that the western banks of the Laguna had several small villages of Coast Miwok peoples, while the eastern part of the watershed had both Coast Miwok as well as Pomo habitation. The ancient Laguna of 2000 BC supported these tribes with abundant fish, fowl and tule reeds for manufacturing homes and canoes.^[5] In 1833, the original Mexican land grant occurred that involved lands of the Laguna watershed. In the year 1870, the railroad arrived with associated channelizations and intensification of agricultural uses. By the 1960s, encroachment of the vast eastern plain was almost complete, and the previously rich run of 1.6 million anadromous fish had virtually collapsed.
Historically the Laguna had been the receiving waters for untreated (and later treated) sewage from the city of Santa Rosa; however, the city gradually became a partner in Laguna restoration by improving the treatment of wastewater and eventually minimizing discharge through tertiary wastewater irrigation reuse for hay farming. By 1989 over 92 percent of the Laguna's historic riparian habitat had been lost, and its water quality had reached critically poor levels.
In that year the Laguna de Santa Rosa Foundation was formed to mobilize public and private resources for preservation and restoration of this natural area. The Foundation has developed education programs, implemented a number of hydrological and ecological restoration projects, and published ''Enhancing and Caring for the Laguna'', a restoration and management plan for the Laguna watershed, in 2006. Primarily funded by the California Coastal Conservancy and developed with participation by hundreds of Laguna stakeholder organizations and individuals, the plan serves as a framework for improvement of the Laguna's ecological functions and development of trail access.

Geology

As recently as the Miocene period, this entire region was submerged below the Pacific Ocean. Around 12 million years ago, processes of uplift and volcanic action formed the Mayacamas and Sonoma Mountains to the east and established the main geomorphic features of the present day landscape. Millions of years of stream erosion carving these mountains led to the rich soils of the Santa Rosa Plain and the Laguna de Santa Rosa drainage that meandered on the vast plain. The western hills are much less pronounced in elevation, and contribute far less to the drainage area of the basin.
Soil types within the Laguna are quite complex and vary by reach. Many of the soils of the immediate Laguna area are classified as Clear Lake clay; these soils are associated with regions of poor drainage, and are underlain by alluvium and sedimentary rock.^[6] The surface of these soils is typically dark gray, and soils acidity ranges from slight to medium for the first 39 inches (100 cm) of depth; underlying this upper soil layer is a moderately alkaline dark gray clay. Deeper, typically below 46 inches (117 cm), is a gray and light brownish gray moderately alkaline clay. Wright loams are also present within the Laguna. The slope of the drainage basin is typically zero to two percent.

Hydrology and water quality

The Laguna de Santa Rosa is a principal tributary of the Russian River; largest among the many tributaries of the Laguna are Mark West Creek, Santa Rosa Creek, Copeland Creek, Hinebaugh Creek, Five Creek, Washoe Creek and Blucher Creek. The Laguna consists of a winding ribbon of flow in the dry summer season and a massive floodplain that resembles a series of lakes in the winter storm season. There are numerous vernal pools on the floodplain that extend for miles to the east, which support many rare and endangered species.
With regard to water quality, the Laguna de Santa Rosa is listed as Impaired under the federal Clean Water Act for sediment, nitrogen, phosphorus, temperature, mercury, and dissolved oxygen, its six such listings being the most of any water body on the North Coast of California.

Ecology

The Laguna de Santa Rosa is a complex of habitat types including freshwater riparian forest and floodplains, seasonal wetlands and vernal pools, upland valley oak savanna and freshwater tule marsh. A number of rare and endangered species are found in the Laguna, such as the California Tiger Salamander ''(Ambystoma californiense)'', California freshwater shrimp ''(Syncaris pacifica)'' and Sebastopol meadowfoam ''(Limnanthes vinculans)''. As an element of the Pacific Flyway, the Laguna is home to a large variety of avifauna including Clapper Rail, Canada Goose ''(Branta canadensis)'', Turkey Vulture ''(Cathartes aura)'', Black-necked Stilt ''(Himantopus mexicanus)'', Burrowing Owl ''(Athene cunicularia)'', Great Egret ''(Casmerodius albus)'', Great Blue Heron ''(Ardea herodias)'' and American Kestrel ''(Falco sparverius)''. More than 200 species of birds are known to reside in or feed and rest in the Laguna in the course of migration. Salmonid species listed as threatened or endangered species are known to travel through the Laguna to spawn in its tributaries, including steelhead trout ''(Oncorhynchus mykiss)'' and coho salmon ''(Oncorhynchus kisutch)''.

Stewardship & Land Management

Much of the Laguna's most important habitat is in private hands, and multiple public agencies regulate various aspects of the Laguna's water, lands and natural resources. At the federal level, the U.S. Army Corps of Engineers has played a role in analysis of water quality, especially related to sediment issues, and the National Marine Fisheries Service of the National Oceanographic and Atmospheric Administration regulates critical habitat and recovery efforts for threatened and endangered salmonid species. The state of California, through its Department of Fish and Game, has ownership involvement as well as an enforcement role in species protection, while the North Coast Regional Water Quality Control Board is responsible for regulating water quality in the Laguna. Locally, the Sonoma County Water Agency manages areas of the Laguna for flood control, and the City of Santa Rosa's Subregional wastewater System's main plant is located in the Laguna floodplain and owns and manages adjacent lands for storage and agricultural reuse of treated wastewater as well as for habitat values. The City of Sebastopol also owns lands in the Laguna which it manages as public parkland. In the private sector, the Laguna de Santa Rosa Foundation plays an active role in planning, public education, restoration, research and implementation of education programs in the Laguna.

See also

★ Santa Rosa Creek

★ Coho salmon

References

1. ''Santa Rosa Quadrangle'', Fifteen minute series, USGS Quadrangle Map, U.S. Government Printing Office, Washington, D.C. (1958)
2. Gina Covina, ''New Life for the Laguna: Santa Rosa's Wetlands not Going to Waste'', Bay Nature, October-December, 2005
3. ''Laguna de Santa Rosa Drainage Project'' [lengthy description, history, land use and natural resources of the Laguna de Santa Rosa], Sebastopol Times, Sebastopol, Ca., May 15, 1915
4. State of California regulatory compliance status for Laguna de Santa Rosa
5. Laguna de Santa Rosa Foundation library archives, Laguna Foundation, PO Box 7886, Santa Rosa, CA 95407 (2006)
6. ''Soil Survey, Sonoma County, California'', U.S. Department of Agriculture, Soil Conservation Service, Government Printing Office, Washington D.C., May 1972

External links

★ Laguna de Santa Rosa Foundation official site

★ Community Clean Water Institute Laguna de Santa Rosa water quality monitoring