Expert in Surface Water Hydrology
Expert ID: 727492
Expert W. Expert is a hydrologist and natural resource scientist with over 18 years of professional experience in surface water hydrology and hydraulics, stormwater management, flood control, constructed wetland design, watershed analysis, erosion/sediment control, water control structure design, groundwater dynamics, soil-water characteristics, aquatic ecosystem restoration, site-development planning, vegetation management, and planting/landscape design, and wetland mitigation permitting (i.e. CWA Section 404 and Section 401). He has prepared numerous stormwater and watershed management plans, performed hydrological investigations, designed structural control treatment measures, and implemented environmental impact assessments, mitigation and monitoring programs, and associated regulatory compliance studies/reports (i.e., National Pollutant Discharge Elimination System [NPDES], California Environmental Quality Act [CEQA], National Environmental Policy Act [NEPA]).
Expert provides expertise in hydraulic and hydrologic engineering, design of stormwater collection/treatment systems, and in the application and interpretation of surface water and stormwater management modeling software. Expert has an in-depth knowledge of the following hydrologic/hydraulic modeling software: TR-55, TR-20, StormNET, HEC-1, HEC-RAS, and HEC-6, Enhanced RMA, MIKE 11 and other statistical, stochastic and deterministic programs/methods for design evaluation of hydrologic/hydraulic processes. His physical and numerical modeling experience includes drainage basin studies, design event and continuous simulation flow modeling, freshwater and tidal wetland processes, wetland water balance studies, sediment transport investigations, chemical fate and transport studies, land-use developments, stream channel design/rehabilitation and associated hydraulic studies.
Expert is recognized by the Bay Area Stormwater Management Agencies Association (BASMAA) and is included in BASMAA’s “qualified consultants” list for stormwater professional services. In addition, he provides diverse experience in regulatory negotiations, site planning, and engineering design to facilitate compliance with CWA Phase I and Phase II NPDES regulations. Expert has prepared and implemented numerous stormwater management programs and designed and retrofitted stormwater facilities/BMPs at numerous sites throughout the San Francisco Bay Area and throughout Northern California.
• McCoy Basin Long-term Management Plan, Solano County Water Agency, Fairfield, CA. The initial phase included evaluation of existing regulatory constraints and physical hydrologic/hydraulic constraints to basin operations given contributing watershed, channel, floodplain, and watershed conditions. The ongoing project includes coordination with the Regional Water Quality Control Board and the development operational procedures and management alternatives (structural and non-structural solutions) to mitigate existing and future flooding, sediment/vegetation management, and water quality concerns. Site surveys of channel and basin features and associated plans and cross-sections were developed to support hydraulic capacity modeling. Typical flow patterns, timing and volume of releases from Putah South Canal through McCoy Basin were evaluated in the interest of water quality and flow attenuation to accommodate Basin discharge during design storm events. Additional watershed research and Geographic Information System (GIS) based mapping was conducted to characterize potential future development scenarios within surrounding watershed areas to support hydrologic/hydraulic modeling efforts and third party studies. A range of potential structural and non-structural (source control) measures were examined to improve hydraulic functionality/capacity of the basin and to improve water quality of the effluent discharge including an evaluation of outlet configuration options that would provide increased hydraulic control. Potential outlet excavation options and construction of surrounding basin berms were considered to allow for controlled low flow discharge, flood bypass flows and potentially feasible increases in basin storage capacity.
• Las Positas Community College Facilities Master Plan Development, Chabot-Las Positas Community College District. Provided civil engineering design services to the Chabot-Las Positas Community College District as part of their proposed Las Positas College Facilities Master Plan Development for stormwater management and associated drainage improvements. Activities include the critical path items (technical studies and engineering services) needed to support the detailed engineering design and the preparation of improvement plans for proposed drainage improvements and associated tasks required by local, state, and federal regulatory agencies. The work included review of previous HEC-RAS modeling studies to support development of design options for new stormwater management facilities required to satisfy Alameda County hydromodification and stormwater quality treatment standard requirements for new development using the Bay Area Hydrology Model (BAHM). Following modeling, a detailed Hydrology and Drainage Study was developed to support the conceptual design. Consensus on revisions to the proposed conceptual design was reached and 75% civil design and grading plans were prepared for the facilities, including connection to the existing storm drain system, design around existing utilities, re-run of the BAHM model, and finalization of the Hydrology and Drainage Study. STORMCAD modeling software was also utilized to determine the extent to which the hydraulic grade line would be impacted to avoid potential flooding impacts. By modeling in this fashion, the effect of rerouting flows in the existing campus storm drain system through the planned stormwater treatment and flow duration control facilities could be accounted for in the facility design.
• Feasibility Assessment for Managing Stormwater Loads in San Francisco Bay, Clean Estuary Program. A literature review was conducted to determine the current state of knowledge on stormwater pollutant loads and the types, load reduction benefits, costs, and feasibility of best management practices (BMPs) for addressing stormwater problems in the Bay Area. An inventory of Bay Area BMPs was performed using the National Stormwater BMP Database structure as a template for data collection. BMPs were categorized as site design, source control, or treatment and the focus was on post-development structural source and treatment control measures. Examples of BMPs inventoried includes: street sweeping, porous pavers, eco-roofs, detention and retention basins, constructed wetlands, and vegetated swales. Vendor supplied BMPs such as underground vaults, hydrodynamic screens, and catch basin inserts also were inventoried. The resulting database includes information on catchment characteristics, design criteria, costs, effectiveness and operation and maintenance experience and issues. A computational matrix was developed to evaluate and compare the key pollutant loads and BMP performance parameters at the watershed scale. The information developed in the project was input to the matrix to calculate contaminant loads reduced or avoided. The parameters were varied through their respective range of probable values to quantify the range of uncertainty in the pollutant load reduction results. The proposed approach allows the CEP to recalculate load reductions when new or more refined information becomes available and will facilitate future refinement of BMP strategies to optimize contaminant load reduction.
• Computer Aided Solute Transport Modeling of Aquatic Diquat Applications to Determine Setback Distance and Time for Treated Water Use, Syngenta Crop Protection Inc. Developed and performed a series of finite element network modeling studies to simulate the fate and transport of the herbicide diquat dibromide (Diquat) for two agricultural scenarios. Using the RMA-GEN, RMA-10, RMA-11 and RMA-PLT applications from the Resource Modeling Associates’ (RMA) Enhanced RMA modeling suite, a series of computer aided hydrodynamic and chemical fate and transport simulations were conducted to estimate concentrations of Diquat for two environmental scenarios: a generalized uniform canal setting and a lake/reservoir setting. The objective was to model a range of Diquat application rates directly on each water body in order to determine holding time and setback distances required for the applied herbicide concentration to reach acceptable background levels for either drinking water or irrigation water intakes. The work resulted in the preparation of a technical memorandum containing a summary of the modeling approach, model inputs, graphical concentration profiles, detailed output concentration values, holding times, setback distances, and summary data visualizations.
• Groundwater Mounding Evaluation and Litigation Support for the Malzacher Ranch Property, Santa Paula, California. Provided groundwater evaluation and litigation support services for the Malzacher Ranch Property in Santa Paula, California. The City of Santa Paula produced an Environmental Impact Report (EIR) for the proposed construction of a wastewater treatment plant in several lots immediately adjacent to the Malzacher property. However, the City’s EIR did not adequately consider the impact of the proposed operation on the Malzacher property. LFR provided professional technical services to determine potential impacts to groundwater underlying the Malzacher property from the planned construction and operation of proposed percolation ponds immediately adjacent and upgradient to the Malzacher’s water supply well. The evaluation included modeling of water application rates, soil infiltration and groundwater mounding potential at the property as well as an evaluation of potential groundwater quality impacts.