Flood Control Studies

• Preparation of Hydrologic Planning Standards for City of Fairfield, California. Prepared the Hydrology and Hydraulics section of the city Planning Manual. These standards dictate the requirements and methodologies to use for submittals to the city's Planning Department for all proposed developments. Client: John Pederson, City of Fairfield Planning Dept.
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• Municipal Detention Storage Alternatives Investigation, Ukiah, California. Various underground detention storage sites on city park properties were evaluated to attenuate storm drain system peak flows at a downstream problem flooding area. A watershed model of a portion of the City of Ukiah was developed for the analysis. Client: City of Ukiah Public Works Department
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• Determination of Floodflow Patterns For Project Design, Yountville, California. Engineering investigations were undertaken for the development of the Vintage Inn resort hotel in Yountville. Repeated prior flooding, experience, both at the project site and throughout the town of Yountville, had indicated the need for a comprehensive hydrologic analysis of potential sources of, and solutions for, flooding events within and adjacent to the project area. This report provided hydrologic modeling to determine the threat of flooding across the project site, established the Q-100, Q-50 and Q-10 flows for the site and presented a drainage scheme for the proposed handling of post-project flood flows. Client: Vintage 1870
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• Alternatives Screening and Evaluation of flood control measures along Sulphur Springs Creek, Benicia, California. Synthesized flood hydrographs with various frequencies up to 100-year flood for study area using rainfall-runoff simulation model HEC-1, simulating various operating plans for upstream reservoir (Lake Herman). Calculated water surface profiles from mouth of creek at Suisun Bay through study area for various hydrograph peak flows using computer program HEC-2 simulations. Recommended flood control measures resulting from study consisted of levee heightening, channel and bridge clearing, and diversion of stream flows by overflow weir into retention basin and alternate channel system. Client: Benicia Industries
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• Storm Drain Master Plan, Lagoon Valley Project, Vacaville, California - Developed detailed hydrology and hydraulics models to evaluate pre- and post-project 100-year flood flows through Lower Lagoon Valley. Urban runoff water quality standards and flood control criteria limiting post-project flows to 90% of existing condition flow levels were to be met. Final stormwater system design involved combination of diverting flows from commercial properties to retention basins, modifications to Lagoon Valley Lake flood control operations, and the diversion of a major portion of Lagoon Drain flood flows to a conduit system parallel to the natural channel. Client: MacKay & Somps/Sammis Properties
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• Flood Control Feasibility Study along Sapphire Springs Creek, Benicia, California. Evaluated alternative flood control measures using hydraulic backwater model HEC-2 in order to provide 100-year flood protection for automobile unloading facility. Prepared preliminary designs for recommended measures including channel modifications and railroad bridge widening and heightening. Involved Corps of Engineers and Fish and Game permits, preparation of final plans and specifications and construction management. Client: Southern Pacific Transportation Company
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• Hydrologic Simulation of Urbanization, St. Helena, California - Study to evaluate watershed response to long-term urbanization and to quantify effect on stream bank erosion at Vineyard Valley Mobile Home Park. Client: Mr. Richard MacDonnel

Dam and Reservoir Projects

• Lake Orinda Dam & Spillway Investigation, Orinda, California. Evaluated the adequacy of the dam spillway in passing the California Division of Safety of Dams (DSOD) Probable Maximum Flood (PMF), a 72-hour, 20,000-year event. Numerical modeling of spillway routings under existing conditions and with various alternative spillways modifications using HEC-1 and HEC-2. Client: Orinda Country Club .
• Design of Dam and Reservoir for Residential Subdivision, Sonoma California. Prepared the engineering design and construction specifications for a multi-use reservoir, including earthfill dam, rock spillway and low-flow outlet channels. J.F. Shea Homes .
• Dam Break Inundation Map Preparation for the State Office of Emergency Services (OES), Scout Lake, Willits, California - The simulation of a complete dam failure/breach was done using Corps of Engineers Computer Program HEC-1 and OES modeling criteria. The model produced the dam breach flood hydrograph and routed it through the downstream channel, to the valley floor. A two-dimensional hydraulic backwater model was constructed using Corps of Engineers Computer Program HEC-2. The dam breach hydrograph peak flows were input to the HEC-2 model to determine and map the areas of downstream inundation. Client: Boy Scouts of America. .
• Design of Debris Basin and Flood Control Appurtenances for Residential Property, Santa Rosa, California. Design of flood control project on Matanzas Creek incorporated earthfill dam and access road, debris sorting drop inlet structure, low level outlet and emergency spillway. Client: Ms. Marlice Gardner

Flood Zone Studies

• Floodplain  and Floodway Impacts Determined for Condominium Project, Broaddus Creek, Willits, California. Detailed HEC-RAS hydraulic model of Mendocino County creek channel, its overbanks and numerous bridges was developed for analysis of the project's impacts, in conformance with FEMA and local floodplain regulations and as part of an application for a FEMA Letter of Map Revision (LOMR). Client: Dorn Construction, Redwood Valley, CA .
• FEMA Flood Insurance Restudy, Contra Costa County California - Meeting the requirements of the National Flood Insurance Program, 28 streams, covering approximately 57 stream miles, were studied to determine flood hazard areas and actuarial flood hazard rate zones. Extensive use of the Corps of Engineers computer program HEC-2 was employed in this effort to reevaluate flood zones where either significant watershed or channel conditions have changed or detailed studies have not been conducted. Client: FEMA .
• Preparation of Letters of Map Revision (LOMRs), Vallejo, California - A complete review and update of watershed meteorology, hydrology and stream and storm drain system hydraulics was conducted in order to remap the 100- and 500-year floodplains on three city watersheds. Derivation and routing of the base floods was done with computer model HEC-1, and plotting and mapping of floodplain backwaters was done with program HEC-2 and other hydraulic storm drain system models. Client: Vallejo Sanitation and Flood Control District .
• Preparation of Watershed Flood Map, Crazy Creek, Lake County, California. Complete determination of 10-year through 100-year flood flows and associated floodplain mapping was developed, using HEC-HMS hydrologic and HEC-RAS hydraulic models, for the Crazy Creek watershed in southern Lake County, California, as part of the preliminary investigations conducted for a residential development. Client: Brookfield Homes, Danville, CA .
• Determination of Floodplain Impacts and Preparation of CLOMR-F Request, Ukiah, Mendocino County, California. FEMA's original HEC-2 model was imported into a HEC-RAS computer model and updated to determine the impacts of a proposed residential development on the Russian River floodplain. A Conditional Letter of Map Revision Based on Fill (CLOMR-F) request was prepared and submitted to FEMA. Client: Pinnacle Homes, Santa Rosa, CA

Hydraulic Design

• Evaluation of Combined Sanitary/Storm Sewer System Capacity, UPRR yard development, Sacramento, California. A portion of the City of Sacramento's combined sanitary/storm sewer system was analyzed using the US EPA's Storm Water Management Model (SWMM) computer program. The existing capacity of the system was determined, and various means of routing drainage from the planned development project to the existing system were analyzed. A storm drainage master plan, incorporating on-site detention storage, was developed to adhere to strict cfs per acre maximum outflow requirements for the site, and so as to not create adverse effects anywhere in the downstream system. Client: Morton & Pitalo, Inc. and City of Sacramento .
• Landfill Expansion Hydrology and Hydraulics, Sunshine Canyon Landfill, Los Angeles, California - In particular, the conceptual design of the sediment basin, its inlet and outlet pipes and energy dissipation structures, and the sizing of all v-ditches and piping to convey runoff from the fill slopes to the sediment basin was developed. All drainage improvements were designed to handle the 100-year design discharge utilizing U.S. Army Corps of Engineers computer programs HEC-1, to estimate storm water runoff hydrographs, and HEC-2, to determine culvert sizing and inlet configurations. Client: Purcell, Rhoades & Associates .
• Hydraulic Analysis of Flood Control Alternatives for the Northgate Project, Vallejo, California. Alternative plans included the design of various reaches of channel along Rindler and Blue Rock Springs Creek and the diversion of flood flows to underground conduit systems, through the Solano County Fairgrounds, to the confluence with Lake Chabot. System was modeled using computer programs HEC-1 and HEC-2. Client: Bissell & Karn .
• Feasibility and Alternatives Screening Study for Redwood Shores Lagoon Stormwater Discharge Facilities - Evaluated the adequacy of the lagoon discharge facilities for maintaining maximum water surface levels in the event of 100-year runoff/tidal conditions. Conducted an analysis of the hydraulic efficiency of the existing outlet works based on field gathered outflow and tidal data. Developed a hydraulic computer model to simulate the operation of various outlet facility layouts during the occurrence of coincidental low frequency rainfall-runoff events and high tidal cycles. Client: Redwood City .
• Hydraulic Analysis and Creek Design of a three-quarter mile reach of Rindler Creek in connection with the Northgate Development Project, Vallejo, California. The project involved the relocation of the Creek to a partially above- and partially below-ground drainage system and necessitated the design of several energy dissipation and drop structures to manage the alternating super- and sub-critical flow conditions of the creek. Client: Bissell & Karn .
• Design of Residential Storm Drain System in Accordance With Strict No Adverse-Impact Ordinances, Corvallis, Oregon. Drainage system employed on-site storage and pervious asphalt areas as means of mitigation for any environmental impacts on the watershed. Client: Mr. Mikel Bryan

Water Supply Investigations

• Meteorologic/Hydraulic Investigation of Sacramento River Delta island/reservoir, San Joaquin County, California - Conceptual design for the spillway and appurtenances to convert Bouldin Island to a fresh water supply reservoir. Stormwater runoff to the reservoir was estimated using U.S. Army Corps of Engineer's computer program HEC-1, Flood Hydrograph Package. The HEC-1 computer model was set up to simulate a 4,500 year, 96-hour storm using the Station Angle Method of determining precipitation depths from the records of a surrounding rain gage network. The investigation developed a spillway sizing based upon California Division of Safety of Dams (DSOD) criteria for the spillway's ability to pass the DSOD designated design flood. Client: Delta Wetlands, Inc. .
• Drought Study, Vineburg, California - Hydrologic and geologic evaluation to calculate the 50-year drought for southern Sonoma Valley and determine its effect on a surface water reservoir's ability to remain at minimum pool elevation. The effects of the 50-year drought on nearby pumping rates and natural recharge of aquifer to determine resulting effects on the water table were evaluated. Client: Mr. Ron Groskopf .
• Water Supply Feasibility Study, The Geysers, California - Conducted feasibility and preliminary project screening studies for dam and reservoir and instream extraction facility water projects on Big Sulphur Creek in Sonoma County, California. Analysis involved hydrologic simulation of watershed and simulated operations of alternative projects using computer model HEC-1. Project construction is now complete. Client: Northern California Power Agency .
• Meteorologic and Stream Gage Station Installation, Monterey County, California - Two meteorologic stations and three stream gages were sited and installed as part of an evaluation of the water resources for the 20,000 acre Rancho San Carlos. The meteorologic stations were designed to gather rainfall and evaporation data and the stream gage stations were placed on two creeks so as to keep a continuous record of flows for a planned 5-year period. The wide range of flows occurring on the two streams and the need for a great deal of accuracy in measurement during low flow condition required the design of combination v-notch/rectangular weirs on the streams. Ultrasonic flow sensors with custom stream flow rating curves programmed into the flow recorders were used to gather and store the data and keep a continuous record of flow volumes. Client: Rancho San Carlos

Storm Water Quality

• NPDES Construction Permit Notebook Preparation. The Notebook was prepared for a major land developer for application to all development construction projects in northern California, emphasizing erosion and sediment control measures. It contains a boiler plate Construction Permit Storm Water Pollution Prevention Plan (SWPPP), with all of the standard verbiage contained within the plan, and choices of standard Best Management Practices (BMP's) to select from, as appropriate, for each project. The Notebook has appendices with example pollutant constituent lists, pollution control procedures, water quality monitoring methods and Best Management Practices (BMPs) from which to choose for filling in blank sections. It also contains example completed Construction Permit packages and detailed instructions for developing a site specific SWPPP from the materials contained in the Notebook. Client: Shapell Industries of Northern California .
• Hydrologic Review of Proposed Hard Rock Mining Operation, Mendocino County, California. The potential impacts of the project to storm water quality and quantity were considered in this review and a series of preventative measures to minimize both erosion potential and turbidity/pollution of runoff from the project area were developed. These measures consist of both structural and non-structural standard Best Management Practices, or BMP's, for storm water quality protection, as recognized under the state's NPDES Storm Water Quality Program. This evaluation provided much of the analysis necessary for the preparation and implementation of a Storm Water Pollution Prevention Plan (SWPPP) and Monitoring Program, as required by the state Water Resources Control Board, for compliance with the state's General Industrial Storm Water Quality Permit for mining operations. Client: Shuster Sand and Gravel .
• Storm Water Quality Impacts Report, Vasona Junction Park & Ride lot, Los Gatos, California. A hydrologic review of the potential impacts of the proposed Park & Ride Lot on the surface water resources of the Santa Clara Valley and San Francisco Bay. The potential impacts to storm water quality and quantity were considered in this review and a series of preventative measures to minimize both erosion potential and turbidity/pollution of runoff from the project area to Los Gatos Creek were developed. These measures consist of both structural and non-structural standard Best Management Practices, or BMP's, for storm water quality protection, as recognized under the state's NPDES Storm Water Quality Program. Client: Santa Clara County Transportation Agency .
• NPDES Storm Water Quality Compliance, California State Prison, Solano - Prepared Storm Water Pollution Prevention Plan (SWPPP) and Monitoring Program for the prison and its numerous inmate vocational industrial facilities. A plan of action and all required documentation to put the facility into compliance with the State's Storm Water General Permit for Industrial Activities was developed and implemented. Client: California Dept. of Corrections .
• Preparation of SWPPP for the Construction of a Residential Development, Ukiah, Mendocino County, California. The development of both construction phase and permanent project BMPs was made a part of the Storm Water Pollution Prevention Plan (SWPPP) submittal to the state RWQCB. Client: Pinnacle Homes, Santa Rosa, CA.

Environmental Reviews

• Hydrologic Impact Evaluation for Brookmeadow Development EIR, Santa Rosa, California - The 210-acre, 515-residence development project includes both on-site and off-site drainage courses. Erosion, flooding, and water quality issues were addressed and mitigation measures involving bank protection, easement acquisition, alternate subdrain systems, and channel maintenance were recommended. Client: Harding Lawson/EIP Associates .
• Use Attainability Study, Santa Cruz River, Pima County, Arizona. Conducted inventory to characterize hydrology, water quality, geomorphology, and sediment scour and deposition of Santa Cruz River in Pima County following EPA requirements. Client: Pima County Wastewater Management District .
• Tundra Surface Water Sampling Program, North Slope, Alaska - Developed sampling program and managed field crew gathering surface water and soil and vegetation samples from tundra surrounding drill pads in Kuparuk, Alaska. Analyzed samples for metals and aromatics to evaluate extent of bio-accumulation halo around gravel pads. Client: ARCO, Alaska .
• Water Balance Analyses for the Chateau Fresno Landfill Facility, Fresno County, California - The analyses were conducted to comply with the CRWQCB Tentative Waste Discharge Requirements for the site. The intent of the investigation was to predict quantities of runoff, drainage and leachate generation from the landfill under both interim and final cover profile scenarios. Two distinct modeling methodologies were employed for the evaluation of the water balance: a tabular method developed by C.W. Thornthwaite in the soil and water conservation field, and the Hydrologic Evaluation of Landfill Performance (HELP) computer model, developed by the EPA. Client: Purcell, Rhoades & Associates .
• RCRA Facility Assessments (RFAs) of industrial facilities located within EPA Region VI - Conducted under the RCRA Corrective Action Authority. RFAs identify and evaluate information on releases at RCRA facilities and potential for releases to all media from facility solid waste management units (SWMUs). RFAs are based on State and Federal Agency file information for each facility and are followed up by a Visual Site Inspection conducted by RFA preparer. Preliminary determinations regarding releases of concern and need for further actions and interim measures at facility are presented in RFA reports. Client: A.T. Kearney

Wetlands Studies

• Wetlands Determination, Ox Mountain Landfill, San Mateo County, California - Performed hydrologic and hydraulic modeling of stream courses for determination of extent of wetland habitat under Corps of Engineers definition. Project involved expansion of San Mateo County Landfill into two adjacent canyons and determination of affected riparian habitat for purpose of California Department of Fish and Game and U.S. Army Corps of Engineers permits. Client: Browning Ferris Industries and Washburn and Kemp .
• Hydraulic Analysis of Wetlands, Tri-Cities Landfill, Fremont, California - Evaluated the hydraulic effects of stormwater conveyance facilities on adjacent wetland areas. Modeled rainfall-runoff events of various return frequency and routed flows through conveyance and detention systems to estimate extent and duration of pre- and post-project inundation. Client: Waste Management Industries .
• Hydraulic Impact Analysis for Proposed Wetlands Area, Redwood Creek, Redwood City California - Hydraulic investigation of the possible effects of a wetlands creation mitigation project on the storm water conveyance capabilities of Redwood Creek and the operation of a pump station on that creek. Backwater and tidal influences were modeled to indicate any significant impacts on inundation frequencies and durations. Client: WESCO, Inc.

Sediment Studies

• Sediment Placement Site Feasibility Study, Cogswell Reservoir, Angeles National Forest, California - Evaluated technical, economic, and environmental aspects of various means of sediment removal from flood control reservoir. Alternatives involved removal of 10-million cubic yards of deposited sediment using slurry lines, trucking, and conveyor belts. Client: Los Angeles County Department of Public Works .
• Sediment Yield Evaluation for Marston Ranch Development, Hercules, California - Conducted baseline study on Pinole Creek watershed. Measured creek flows and took sediment samples to quantify effects of watershed development on flow regime and sediment load. Client: Broadmoor/Lusk Homes

Arid Lands

• Low-Level Radioactive Waste (LLRW) Siting Study, Riverside, San Bernardino and Inyo Counties, California - Conducted preliminary screening of hydrologic and meteorologic data in arid areas of state to determine possible flood hazard areas to exclude from project consideration. Determined maximum water surface elevations resulting from severe storm events, up to the possible maximum storm. Characterized flood potential of wash systems within each of 3 most feasible sites, and recommended hydraulically superior locations within each site. Client: U.S. Ecology .
• Groundwater Recharge Study for the Mojave Generating Station, Laughlin, Nevada - Performed climatologic and hydrologic investigations in conjunction with hydrogeologic assessments to evaluate potential for recharge of flood flows into desert alluvium. Simulated probable maximum precipitation (PMP) event and 100-year flood. Client: Southern California Edison