South Bay Salt Pond Interim Stewardship Plan


Client: Cargill Salt Division
Location: San Mateo, Santa Clara, and Alameda Counties

Primary Responsibilities:

  • Tidal Hydraulics Analysis to allow tidal flow and to control salinity

Cargill Salt proposed a land transfer of part of the salt evaporation pond system to the National Wildlife Service. As part of the transfer, the evaporation ponds were operated to maintain the existing open water conditions in the ponds on an interim basis until the Service had established long-term plans for the preferred land uses and pond operations. Schaaf & Wheeler was responsible for tidal hydraulics analyses of the individual pond systems. The objective of the hydraulic analyses was to identify operational measures that allowed tidal flows through the pond systems to maintain the existing open water and to control salinity levels in the ponds. The hydraulic analyses evaluated the inlet and outlet facilities, transfers between ponds, and design water levels within the pond systems.

Santa Clara County Drainage Manual

Client: County of Santa Clara

Schaaf & Wheeler prepared a storm drainage manual for the Santa Clara County Department of Public Works, a complete revision of the 1966 edition. The manual provided methodologies to evaluate the impact of development on storm drainage infrastructure and to enable drainage facilities design to accommodate planned growth and redevelopment. Schaaf & Wheeler analyzed new precipitation statistics to prepare rainfall intensity-duration-frequency curves, proposed hydrologic procedures to be used in planning and design, and new drainage standards and details. Some examples of topics covered by the manual include:
- General Drainage Policies
- Flow Estimation Methodologies
- Hydrograph Development and Routing
- Hydraulic Analysis and Design
- Storage Facilities, Retention and Detention
NPDES Permitting
- Other Stormwater Management Regulations.

Schaaf & Wheeler also led workshops for Santa Clara County constituents who have responsibility for stormwater management to review and discuss the methodologies recommended in the manual.

Coyote Valley Hydrology and Water Supply Evaluation

Client: City of San Jose

The Coyote Valley is currently a rural swath of land between the cities of San José to the north and Morgan Hill to the south. The area is within the sphere of influence of the City of San José and the City has developed the Coyote Valley Specific Plan (CVSP) per the San José General Plan land use designations. The Specific Plan calls for a total of at least 26,400 residential units and 55,000 new jobs to be developed in Coyote Valley. Schaaf & Wheeler conducted hydrologic analyses of the Coyote Valley, in support of the Coyote Valley Specific Plan's Composite Core Plan. Specifically, firm engineers examined potential hydrologic impacts at the confluence of Fisher Creek and Coyote Creek. Starting with the effective HEC-1 models, corrected effective models were built to reflect changes within the watershed since the effective FIS was first published in 1982. From the corrected existing conditions model, Schaaf & Wheeler created a post-CVSP conditions model to evaluate changes in runoff due to the proposed land use plan and flood control infrastructure. Schaaf & Wheeler also recommended alignment and conceptual design principles for the restoration of Fisher Creek within the CVSP area. Schaaf & Wheeler also prepared a water supply evaluation for Coyote Valley. California Senate Bill 610 (SB610) provisions require detailed information regarding water availability be provided to city and county decision-makers prior to approval of specified large-development projects. Schaaf & Wheeler evaluated the water supply assessments prepared by multiple water retailers in the CVSP area, and working with both the City and Santa Clara Valley Water District, evaluated alternatives and recommended a water supply plan of action to deliver reliable water resources to the build-out CVSP area during normal and drought conditions.

Hydrology and Hydraulics Study of the El Charro Specific Plan

Client: City of Livermore

The El Charro Specific Plan Area, a portion of northwest Livermore considered for development, is subject to flooding from the Arroyo Las Positas and the Arroyo Mocho. The City is concerned that reduction in floodplain storage, due to development, could result in increased peak discharges downstream on the Arroyo de la Laguna.

Schaaf & Wheeler was brought in to establish a baseline, or existing condition, that would help determine possible downstream effects from development in the El Charro Area. Schaaf & Wheeler analyzed the existing conditions hydrology as well as the hydrological effects of three proposed roadway alignments and several design alternatives. Firm engineers also analyzed stormwater runoff and flooding using the effective Zone 7, FEMA-accepted HEC-1 hydrology model, modified to provide greater detail in the El Charro Region.

Results showed that any increased flow may result in increased flooding and erosion downstream of Bernal Avenue. Schaaf & Wheeler detailed these findings and explored a number of flood control alternatives in a report to the City.

Dam Break Analyses and Inundation Mapping


Client: South Feather Water and Power Agency
Location: Little Grass Valley, Sly Creek, and Lost Creek Dams in Butte and Plumas Counties

Under the Federal Energy Regulatory Commissionís (FERC) dam safety program, Emergency Action Plans (EAPs) are required to be reviewed and reissued every five years for dams with high and significant hazard ratings. One component of the 2015 reissuance of the EAPs for the three subject dams (Little Grass Valley Dam, Sly Creek Dam, and Lost Creek Dam) is a revision of the inundation maps that were initially developed in 1990. These dam break inundation studies modeled the catastrophic failure of Little Grass Valley Dam, Sly Creek Dam, and Lost Creek Dam. Dam failure inundation maps were developed to map the resulting flood from dam failure.

Trash Capture Plan


Client: City of Mountain View
Location: Mountain View, CA

Schaaf & Wheeler completed a trash capture feasibility plan to assist the City in complying with the Regional Municipal Permit Section C.10 Full Trash Capture for the 2017 70% reduction goal. The study was built off of the 2014 Long Term Trash Reduction Plan and analyzed the Cityís existing storm drainage system and trash capture efforts to determine the most feasible alternatives for meeting the 70% trash reduction goal. The plan reviewed the Cityís Trash Management Areas for installation of trash inlet filters, in-line devices and end of pipe full capture devices. Cost estimates, hydraulic impacts and estimates of trash capture volumes were determined for each of the 12 full capture device alternatives studied. Conceptual level drawings were created for each alternative. The final Feasibility Study will be used by the City to meet their C.10 trash capture requirements.

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