Enhancement Plan. For the City of Mountain View, 1991-00. This project
involved extensive modeling with a tidal hydrodynamic model to design a
solution for enhancement of inner Charleston Slough, review of construction
plans, and monitoring of post-construction hydrologic conditions The modeling
included calculation of tidal flows with various culvert configurations,
calculation of bed shear stress and analysis of potential channel scour, and
modeling of potential sediment deposition in the inner slough area. The latter
was carried out using dredging data from Palo Alto Yacht Harbor to calibrate
the sediment deposition model developed by Dr. Ray Krone. The project included
participation in a number of meetings and hearings at BCDC. The project has
been constructed and is working successfully. Since 1998, Coats has been
assisting the City of Mountain View in its monitoring program at Charleston
Review of the Bolsa Chica Lowlands Restoration Project.
For the U.S. Environmental Protection Agency, San Francisco, 2000.
Eight state and federal agencies have proposed a project to create a new ocean
entrance at Bolsa Chica, in order to enhance the diked wetland and off-set
habitat loss at the Ports of Long Beach and Los Angeles. Coats assisted EPA
with its review of the EIR/EIS and related technical documents, incorporating
input from two experts in water quality and sediment transport modeling.
Peacock Lagoon Water Quality Study. For Peacock Gap Golf
Course, 2000. Hydroikos, together with Tom Burke and Robert Abbot, evaluated
water quality and circulation problems in a salt water lagoon that receives
runoff from a golf course and residential development. The team developed a
detailed water quality monitoring program for the lagoon.
Wetland Compliance and Mitigation. For the Cline Vinyard, Sonoma,
1995. The client modified drainage on a parcel adjacent to Sonoma Creek by
installing a new culvert, an action considered by regulatory agencies to be a
violation of Sec. 404 of the Clean Water Act. Coats helped find a solution to
the problem by modeling the previous, existing and mitigated conditions on the
site. The mitigated condition included culvert modifications to enhance wetland
conditions on the site.
Design Guidelines for Channels in Tidal
Wetlands. For the US Army Corps of Engineers Waterways Experiment
Station, 1994. Coats developed design guidelines and criteria for design of
tidal slough channel, using an extensive data base relating channel width,
depth and cross sectional area to tidal prism. Relationships were also
developed for channel side slope, and channel planform characteristics, such as
density, bifurcation ratio, sinuosity, etc.
EIR/EIS. For the Solano County Planning Department, 1993-1996. Coats
prepared the hydrologic components for both the Draft and Final EIR/EIS on a
project to create an 8,000 acre wetland using dredged material from San
Francisco Bay. The work included: 1) supervising the use the hydrodynamic
models DIVAST and ESTFLO to simulate tidal circulation and determine the
likelihood of channel erosion; 2) using empirical geomorphic relationships to
evaluate proposed design of main channels; and 3) evaluating potential water
quality impacts of the proposed project. Many of the mitigation measures
specified in the Draft document were incorporated into the final design.
Potrero Hills Wetland Enhancement at Hill Slough. For
the Potrero Hills Landfill Co., 1994-96, through subcontract with RMI, Inc.
Coats managed the hydrologic analysis for enhancement of a wetland at the
eastern end of Hill Slough, as mitigation for unpermitted fill. The analysis
included 1) measuring tide height in Hill Slough with a recording tide gage,
and developing a statistical relationship with San Francisco tides; 2) modeling
tidal flow through culverts; 3) developing runoff hydrographs and analyzing the
potential effects on flooding of proposed enhancement of a seasonal wetland.
Enhancement Plan for Bennett Slough, at Moss Landing
Harbor. For Moss Landing Marine Lab and State Department of Parks and
Recreation, 1990. Following the destruction of Jetty Road in the 1989
earthquake, a routing model was used to design a tidal inlet to Bennett Slough,
and to determine the height-duration relationships for various inlet
Enhancement Design for the Blohm-Porter
Marsh. For the Monterey County Planning Department, through ABA
Consultants, 1990. The project developed a detailed design to manage the
Blohm-Porter Marsh, at the head of Elkhorn Slough. The hydrologic analysis
included developing runoff hydrographs for various frequency flood events, and
routing the floods through the marsh against high tides. Design drawings and
specifications for the selected culvert alternatives were prepared by a
Chabot Creek Marsh Flood Analysis. For
the Vallejo Sanitation & Flood Control District., 1988-89. This project
analyzed the flood hazard and constraints and opportunities for reducing
flooding at Chabot Creek, near White Slough in Vallejo. The hydraulic analysis
showed that a planned flood control channel across the marsh was unnecessary,
and would not alleviate existing flood hazards. This conclusion saved the City
of Vallejo over $1 million.
Concord Naval Weapons
Station. Analysis of contaminant transport and site hydrology at Naval
Weapons Station Concord, 1986-1991. This analysis was a part of the Remedial
Investigation and Feasibility Study for cleanup of heavy metal contamination in
tidal and freshwater wetlands. The investigation formed the basis for a
successful lawsuit brought by the Navy to recover damages from parties
responsible for the contamination. It also formed the basis for the remediation
and monitoring plan. Coats testified in Federal Court as an expert witness for
Dept. of Justice.
Evaluation of J-Pond Detention Facilities in
Coyote Hills Marsh. For the Alameda County Flood Control District,
1993. Detention storage was modeled in a freshwater marsh system that receives
runoff from residential portions of Fremont, Ca. The ponds included the DUST
marsh, a demonstration marsh designed to remove pollutants from urban runoff.
Cuixmala Water Resources Investigation. For the
Goldsmith Foundation, 1994. The Cuixmala Biosphere Reserve in Jalisco, Mexico,
was threatened by a proposed resort/condominium complex. Coats worked with a
team of ecologists from the National Autonomous University (UNAM) and the firm
of LSA to analyze the impacts of the proposed development. He assessed the
available water resources at the site; this included pumping tests on existing
wells, streamflow measurements and analysis of existing water resources and
Enhancement Plan for the Azevedo Marshes, at
Elkhorn Slough. For the Nature Conservancy, and the California State
Coastal Conservancy, 1992-93. With funding from the Port of Santa Cruz
Mitigation Fund, Coats developed a detailed conceptual plan for implementation
of the wetland enhancement plan developed previously by ABA Consultants. The
work involved detailed topographic mapping and use of pond routing model to
compare enhancement alternatives.
Restoration. For Hayward Area Recreation & Parks District, 1986.
Using a pond routing model, Coats designed the culvert and circulation system
for abandoned salt ponds that had been isolated from tidal action by action of
an adjacent land owner.
Hamilton Army Airfield Wetland
Restoration. For the California State Coastal Conservancy, 1993. Coats
reviewed the numerous planning documents for closure and realignment of
Hamilton Army Airfield, and prepared a detailed scope of work for wetland
creation on the landing strip parcel. The scope focused on the use of dredged
material to raise the elevation of the site in order to create a tidal salt
Wetland Mitigation for Widening of Highway 37 at Vallejo.
For Caltrans, 1993-1995. Coats analyzed hydrologic conditions and
developed detailed conceptual plans for the wetland creation at the Guadalcanal
Village site (formerly a part of Mare Island Naval Shipyard) and White Slough.
The project included installing and operating two recording tide gages (on the
Base, and at the project site), and using the data to calculate local tidal
datums, and to model the deposition of sediment in the restored marsh. The work
also included analysis of the feasibility of creating a new wetland near the
mouth of Chabot Creek, and modeling of tidal circulation in White Slough.
Highway 237 Wetland Mitigation. For the Santa Clara
Valley Traffic Authority, 1992. This project included: 1) screening potential
sites to find one suitable for the mitigation project; 2) working with the
biology consultants to develop objectives for the project; 2) measuring local
tide heights at two locations in Guadalupe Slough; 3) developing alternatives,
and analyzing them using a hydraulic model and measured tidal inputs; 4)
developing grading plans and excavation estimates; and 5) designing and
implementing a monitoring program for hydrologic aspects of the project. The
project was constructed in 1992 and opened to tidal action. Preliminary results
show that it is heavily used by migratory birds and has rapidly developed a
cover of wetland vegetation.
Huntington Beach Wetland
Restoration Plan (Talbert Marsh). For the Huntington Beach Wetlands
Conservancy, 1986-87. Coats, in cooperation with Wetlands Research Associates
and biologist Barbara Massey, developed a detailed enhancement plan for a
17-acre degraded formerly-tidal wetland at the mouth of the Talbert Channel.
Hydraulic modeling included use of the 1-d estuary model MARSHFLO. Restoration
of the site to tidal action and creation of a new sand dune were part of the
required mitigation for widening of the Pacific Coast Highway. The Plan was
presented in a public meeting at Huntington Beach in Nov. 1986, and accepted by
all of the agencies involved.
Jurisdictional Determinations and
Compliance Review. For the U.S. EPA Office of Wetlands Enforcement and
Compliance, 1991. Coats assisted EPA in its determination of the line of
"Ordinary High Water", and reviewed remediation plans, on several rivers in
California and Arizona.
Kennedy Park Wetland Enhancement
Plan. For the City of Napa Department of Parks and Recreation, 1989.
Coats, together with Wetlands Research Associates, developed a plan for
restoration and enhancement of wetlands and ponds along the Napa River.
Analysis included use of a numerical computer model to analyze alternative
culvert and grading designs. The project has been implemented, and is a
Laguna Canyon Lakes Enhancement Plan. For
Laguna Greenbelt and the California State Coastal Conservancy, with Wetlands
Research Associates, 1992. Coats developed the hydrologic elements of the
enhancement plan. Work included analysis of flood control alternatives and
developing detailed conceptual plans for water quality control, especially for
nutrients and sediment.
Leslie vs. United States. For
the U.S. Army Corps of Engineers, 1989. Coats analyzed the hydrologic
conditions of the Coyote Tract, at Newark, in relation to a dispute involving
wetland jurisdiction. The analysis included measuring tide heights on and near
the site, modeling the ponding of water in a seasonal wetland and investigating
conditions of capillary rise in soil near the water table. The work also
included preparing and giving testimony in Federal Court.
Enhancement Plan for Roberts Landing at San Leandro. For the City
of San Leandro and Citation Homes, Inc., 1990-94. Coats developed a detailed
conceptual plan for enhancement of a 300-acre wetland complex, including muted
tidal and fully tidal areas. The alternatives analysis included use of two
different hydraulic models, calculation of bed shear stress and tide
height-duration relationships. Construction was carried out in summer 1994;
biological and hydrologic monitoring of the site indicates that the project has
been highly successful.
San Rafael Canal Mitigation.
For the U.S. Army Corps of Engineers, 1994.Coats supervised the development and
analysis of alternatives for modifying the hydrology of two sites adjacent to
San Rafael Canal, as part of the mitigation package for the Army Corps of
Engineers flood protection project at San Rafael. The analysis includes
modeling tidal flow using a numerical model, and expressing the results in
terms of the percent of time that a given elevation is inundated. Alternatives
analyzed include installation of adjustable tide gates, and the use of
self-closing tide gates that will allow normal flow most of the time, but close
during extreme high tides to provide flood protection.
Management Plan for the Springtown Alkali Sink. For the
California Department of Fish and Game, 1988. The Springtown Alkali Sink is
habitat for the Endangered plant Cordylanthus palmatus. In collaboration with
two ecologists, Coats studied the hydrology and soil chemistry of the alkali
sink, and developed a management plan for the area. The plan included
designation of management zones, with conceptual development prescriptions for
Management Plan for Tahoe Yellow Cress. For
the California State Lands Commission, 1990-92. Coats developed and wrote a
management plan for the endangered plant Rorippa subumbellata, which is
confined to the sandy shores of Lake Tahoe. He analyzed the hydrologic and soil
factors related to the plant's distribution, and incorporated input from
biology subconsultants on the plant's distribution and habitat requirements.
Mowry Slough Wetland Jurisdictional Determination. For
the California State Lands Commission and State Attorney General's Office.
1993. Coats analyzed the hydrologic conditions and geomorphic history of a
diked subsided wetland adjacent to Mowry Slough, in Fremont. Basis of the
analysis was a detailed geomorphic map of an undisturbed tidal wetland at
Newark Slough. This included cross-section surveys, tidal measurements, and (in
collaboration with Ray Krone), 14C dating of plant remains in marsh sediments
in order to establish the sediment deposition rate. The results were used in
the development of design guidelines for tidal slough channels as well as in
negotiating a settlement with the owner of the Mowry Slough tract.
Union City Marsh Enhancement Plan. For the East Bay Regional
Parks District, 1993. The Union City Marsh is located on the southwest shore of
San Francisco Bay, just north of the Alameda Creek Flood Control Channel (also
known as the A-Line Channel). The area has been diked from tidal action for
many years. Levee construction was probably carried out in phases; remnant
levees run parallel to the channels in the marsh in some areas. Dramatic
changes in the local shoreline have occurred, but the location of interior
channels in the marsh has not changed much since the 1800's. For the project,
Coats supervised the hydrologic analysis to evaluate tidal circulation for
selected marsh enhancement alternatives, and to evaluate storage in the marsh
during storm events. Modeling included use of HEC-1, ESTFLO (a 1-dimensional
gradually varied flow model) and a pond routing model.
Slough Enhancement Plan. For the City of Vallejo, through WESCO, 1990.
Coats analyzed the hydrology of White Slough in relation to tidal flooding and
storm runoff, using a pond routing model. The model results were used to
analyze alternative culvert configurations for enhancing tidal circulation in
the inner slough, while at the same time taking account of flood management
constraints. The final report recommended (among other things) replacing the
existing four damaged culverts with eight new culverts.
consulting for BCDC. For the San Francisco Bay Conservation and
Development Commission, 1981-1996. Coats provided on-call services to BCDC for
13 years, on a wide variety of problems concerning tidal wetlands around San
Francisco Bay. Problems have included jurisdictional questions, and review of
proposed mitigation and enhancement projects.