Difference between revisions of "Potential watershed impacts on Elkhorn Slough"

Revision as of 13:54, 3 February 2011

Sedimentation and Contamination

A watershed-related issue examined by the ENVS 560/L Watershed Systems class at CSUMB.

Summary

The Carneros Creek Watershed that feeds into Elkhorn Slough has many important resources that benefit both humans and wildlife. Due to European settlement in and around the watershed, the natural connectivity of both fresh and salt water bodies has been disrupted. Development such as the cultivation of steep slopes for agriculture and the increase of residential structures and roads has caused major changes in water flow. In addition, human activities allow for the distribution of pollution and pathogens. Various organizations in the region as well as county, state and federal regulatory bodies continuously work to limit the damage to the watershed and the ecosystem that depends on its functions.

Location

Located just inland of Elkhorn Slough along the Central California Coast, water from the Carneros Watershed flows through Carneros Creek into the Slough. The Elkhorn Slough is located within the curve of the Monterey Bay one hundred miles south of San Francisco. The area is bounded by Watsonville to the North and Castroville to the South. Anthropogenic manipulation of the watershed has increased in recent years and is characterized by agricultural and residential development. Residential and agricultural development occurs throughout the Carneros Watershed, but sedimentation and pollution accumulates and the lower stream channels are the most impacted. The Elkhorn Slough Watershed Conservation Plan (1999), was created with intention of preserving the intact natural communities. The plan identified riparian forests in the lower Carneros Creek floodplain and upland ridges with unfragmented maritime chaparral in the Elkhorn Highlands as areas in need of protection and restoration. most of the rich farmlands are concentrated in the area called Springfield Terrace.

Resources at stake

The Elkhorn Slough is a biologically rich wetland system that provides habitat for migratory birds, rare plants species, and nursery grounds for fish. Coastal estuaries and wetlands are one of California's most threatened ecosystems. High priority resources:

• Coastal marsh: Less than twenty-five percent of California's coastal marshes remain intact. Migrant and resident birds such as the Great blue heron and snowy egret use the marsh areas as feeding and roosting habitat. A small breeding population of the endangered snowy plover was found along the shores of the marsh along with nesting pairs of Golden eagles and white-tailed kites and many other species. Studies have shown that due to anthropogenic modifications to the hydrology of the slough much of the historical marshland habitat was lost Van Dyke et al 2005.

• Freshwater wetlands and Riparian forests: The wetlands house numerous threatened and endangered species that depend on moist, cool habitats including the Santa Cruz Long-toed Salamander, California Tiger Salamander, California Red-legged frog. Functioning wetlands also provide important services to the ecosystem by acting as filters to trap sediment and contamination.
• Maritime chaparral and Coast live oak woodlands: Maritime chaparral, a unique California plant community, contains endemic plants such as Hooker's manzanita, Pajaro manzanita, Monterey ceanothus, Eastwood's goldenbush. Coast live oak is a more common plant community, but those found in association with the rare chaparral plants are considered a priority for conservation. In addition, plant communities that are associated upland of riparian forests and wetland areas may have an important role in the life history of the threatened amphibian species(Olson et al 2007).
• Water quality: increase of residential development and agricultural practices on steep slopes surrounding Elkhorn Slough have increased pathogens, chemicals, and nutrients in watershed waterways
• Stream physical structure: erosion caused by human activities has increased sedimentation and has altered or filled in natural waterways

Stakeholders

Many organizations are working to address threats to the valuable resources within the watershed and reverse the damage caused by development. These organizations include:

• Elkhorn Slough Foundation (ESF): a non profit organization concerned with the health, conservation, and management of Elkhorn Slough. ESF also provides educational opportunities (tours, interpretive literature, etc.) for the public ^[1].
• Elkhorn Slough National Estuarine Research Reserve (ESNERR)
• ALBA & Triple M Ranch: maintain sustainable farming practices on their lands and attempt to reduce erosion and pollution flow into downstream waters ^[2].
• Family and corporate farms
• Residents: Residents of Elkhorn Slough and residents of the surrounding watersheds
• County regulators
• US Fish and Wildlife Service (FWS): US FWS designated Elkhorn Slough as a Critical Habitat for the threatened California red-legged frog (Rana draytonii) ^[3] Accessed on Feb. 1, 2011.
• California Department of Fish and Game
• Audubon Society: Elkhorn Slough is listed by the National Audubon Society as a Globally Important Bird Area for migratory birds along the Pacific Flyway ^[4] Due to eutrophication of the Slough, bird food source supplies have decreased. This decrease may have a negative effect on Elkhorn bird populations.^[5]
• Local businesses:dependent on fisheries, recreation and tourism associated with the watershed Moss Landing Harbor at the mouth of the Slough

Laws, policies, & regulations

The Natural Resources Conservation Service (NRCS) Elkhorn Slough Watershed Project aids farmers in soil conservation practices to reduce erosion and subsequent sedimentation of adjacent marshlands.

Residential development is strongly discouraged due to restrictive land use regulations. The Monterey North County Land Use Plan (LUP) designated much of the western portion of the watershed to be used for "Agricultural Preservation" or "Scenic and Natural Resource Recreation." In the Carneros Creek area and the Elkhorn Highlands, land use designation restrict residential development in wetlands, chaparral and ridge tops.

Monterey County has attempted to reduce watershed erosion by enacting ordinances that require permits to be obtained for land clearing, building, and grading. ^[6] Sediments from activities that require development permits in areas of highly permeable soil must be retained on site. Ways in which sediment may be captured include tools such as infiltration basins and percolation pits. In areas of impervious surfaces sediment from the development must be spread on a non-erodible vegetated area.^[6] Government agencies have the authority to charge landowners fines if runoff is detected from agricultural fields.

Federal and State environmental laws include: Clean Water Act, Endangered Species Act, National Environmental Quality Act, California Environmental Quality Act, California Fish and Game Code, etc.

Science

The natural process of sedimentation occurs when loose particles suspended in a stream are deposited along a barrier or a bank. However, when the number of suspended particles in a waterway increases, typically due to human activity, sedimentation occurs too quickly and alters or fills the waterway.

Scientific studies conducted on the watershed effects on Elkhorn Slough have considered runoff from human activities and other alterations of the upstream land and how it relates to the following:

• California sea otter: A study conducted by Miller et al. (2002) indicated an increase in seropositive Toxoplasma. gondii occurrence in sea otters in Elkhorn Slough. T. gondii is a parasitic pathogen with two life stages. When concerning California sea otters it is transferred from the first host(typically a felid and likely a domestic cat) through waterborne fecal matter that is carried downstream to Elkhorn Slough. T. gondii affects muscle and nerve tissue and has resulted in fatal brain infections of California sea otters.

• Steelhead: The steelhead population in Elkhorn Slough has sharply declined in reacent. Sedimentation has altered the physical characteristics of steelhead habitat.

• Human health: Runoff from the watershed surrounding the slough can severely degrade the water quality and may even pose health risks to humans. E.Coli outbreaks between 2002 and 2006 in California were studied to better understand the sources and methods of transport of environmental contaminants (Cooley et al 2007).

Tools

• Denitrification and Decomposition model (DNDC) developed by a team from the University of New Hampshire and the Cooperative Institute for Coastal and Estuarine Environmental Technology (CICEET) is designed to help monitor runoff, specifically Nitrogen and Carbon.^[7]

• Solarization has been studied as a possible tool to help control non-native plants from invading the rare native plant communities. Lambrecht S, D'Amore A. 2010. Restoration note: Solarization as a technique for exotic plant control in a cool coastal region of California. Ecological Restoration (In Press).

• Vessel based LiDAR monitoring has been discussed and tried as a possible method for determining areas of erosion and accretion in Elkhorn Slough. Aerial LiDAR monitoring is the current method for detecting geomorphic changes over an area. However, a drawback to the aerial method is that is best suited for detecting vertical changes. The vessel based LiDAR monitoring is expected to provide finer and quicker detect of changes.^[8]

• Siciliano D, Wasson K, Potts DC, Olsen RC. 2008. Evaluating hyperspectral imaging of wetland vegetation as a tool for detecting estuarine nutrient enrichment. Remote Sensing of Environment 112:4020-4330.

The Elkhorn Slough Foundation has a team of researchers studying estuarine conservation biology and innovative restoration tools. Kerstin Wasson, Research Coordinator

Future research

The importance of the association between coast live oak woodlands and maritime chaparral are still largely a mystery. In addition, the complete life history of the threatened amphibian species also baffles researchers. A great study for a CWSP master's thesis may be to study the effectiveness of several restoration techniques in each of the prioritized habitats.

Disclaimer

This page may contain student work completed as part of assigned coursework. It may not be accurate. It does not necessary reflect the opinion or policy of CSUMB, its staff, or students.

References

1. ↑ About ESF http://www.elkhornslough.org/esf/index.htm
2. ↑ ALBA wetland restoration http://www.elkhornsloughctp.org/reference/subissue_detail.php?SUBISSUE_ID=48&sort=MAIN_PUB&order=ASC Accessed on Feb. 2, 2011
3. ↑ FWS http://www.fws.gov/pacific/news/2001/2001-43.htm
4. ↑ Audubon Society http://www.elkhornslough.org/conservation/why.htm Accessed on Feb. 1, 2011
5. ↑ Elkhorn Slough: Technical Report Series 2009:1 http://www.elkhornslough.org/conservation/why.htm
6. ↑ ^{6.0 6.1} Erosion Control http://www.co.monterey.ca.us/building/docs/ordinances/Erosion_Control.pdf
7. ↑ Modeling Nitrogen in Elkhorn Slough http://www.elkhornsloughctp.org/reference/subissue_detail.php?SUBISSUE_ID=8
8. ↑ Mueller C. An evaluation of vessel based LiDAR surveying as a tool for monitoring short term change in coastal wetlands http://adsabs.harvard.edu/abs/2010AGUFMOS31B1423M Accessed on Feb 3, 2011.

[1]

• Elkhorn Slough Foundation, The Nature Conservancy. 1999. Elkhorn Slough Watershed Conservation Plan.
• Elkhorn Slough Restoration Policy and Economics Report. 2010
• Monterey County Resources Management Agency
• Olson DH, Anderson PD, Frissell CA, Welsh HH, Bradford DF.2007 .Biodiversity management approaches for stream-riparian areas: perspectives for Pacific Northwest headwater forests, microclimates, and amphibians. Forest Ecology and Management. 246:81-107
• Cooley M, Carychao D, Crawford-Miksza L, Jay MT, Myers C, Rose C, Keys C, Farrar J, Mandrell RE. 2007. Incidence and tracking of Escherichia coli 0157:H7 in a major produce production region in California. PLoS ONE 2(11): e1159. doi:10.1371/journal.pone.0001159

Links

• Carneros Watershed
• Sedimentation and Contamination
• Watershed Issues on the Central Coast of California