Advanced Hydro Engineering

2009-06-30T15:16:00.000-07:00

Bridge & Culvert Hydraulic

2009-06-29T15:15:00.000-07:00

Road 80 Widening, Tulare County, CA
Road 80 is a 15-mile length two-lane highway between the cities of Dinuba and Visalia, CA to be widened to four lanes, separated by a median. The length of three existing bridges and five irrigation crossings of the highway must be increased as part of the project. Dr. Lewandowski was the project manager for the hydraulic and scour analysis for the eight revised structures. The bridge crossing of the St. Johns River had experienced long-term degradation, as well as contraction and pier scour. The pile caps and piles below the bridge were exposed due to past scour. Bridges over Cottonwood Creek and Elbow Creek were also analyzed. A HEC-RAS model was developed for each bridge to determine the revised hydraulic and scour conditions.

Dublin Canyon Road Bridge Replacement, Pleasanton, CA
Dr. Lewandowski was project engineer for an analysis of creek impacts from the Dublin Canyon Road widening project. The project is near the confluence of two creeks and required a bridge and scour analysis. A HEC-RAS hydraulic analysis was performed for the revised bridge crossing. The widened roadway also requires a retaining wall to be constructed parallel to the edge of the creek. A scour analysis was performed to determine the retaining wall footing elevation and scour protection measures.

Bollinger Canyon Road Bridge, San Ramon, CA
Dr. Lewandowski was project manager for an analysis of the West Branch Alamo Creek crossing of Bollinger Canyon Road. The crossing had three culverts, one super-span arch and two elliptical culverts, across a wide floodplain. A HEC-RAS model was developed for a multiple opening condition in the bridge. Contraction scour was calculated using the HEC-18 methodology.

San Pablo Creek and Wildcat Creek Floodplain Assessment, San Pablo, CA
Dr. Lewandowski was project manager for this study which included the analysis of thirteen bridges or large culverts along San Pablo and Wildcat Creeks. Many of the bridge configurations in the previous HEC-2 model were updated in a new HEC-RAS model. The HEC-RAS model included modifications to reflect existing conditions that were previously modeled incorrectly or for a new replacement bridge that had been constructed since the previous model had been developed.

Golf Club Road Bridge, Pleasant Hill, CA
Dr. Lewandowski was project engineer for the hydraulic analysis of the bridge. FEMA floodplain boundaries were outside of the channel, with overland flow over the bridge approaches. A HEC-RAS model of the existing and two proposed bridge conditions was developed and used to estimate bridge soffit elevations.

First Street Bridge Replacement, King City, CA
Dr. Lewandowski was project engineer for the hydraulic analysis of the existing and replacement bridges for this three span structure. SR99 Bridge at Big Chico Creek, Chico, CA and Avenue 360 Culverts near Tulare, CA Dr. Lewandowski reviewed hydraulic calculations for these structures to verify that hydraulic conditions were correctly represented by the HEC-RAS model.

Construction Management

2009-06-29T15:14:00.000-07:00

Dr. Lewandowski has construction management experience in the following projects:

Water Pollution Control Plant Expansion, Chico, California;
Wastewater Treatment Plant Expansion, Gresham, Oregon;
Indian Creek Middle Basin Wastewater Treatment Plant Expansion, Johnson County, Kansas.

These projects included office engineering, resident engineering and contract administration support. Office engineering included contractor schedule review, equipment submittal review and correspondence during construction work.

Flood and Storm Water Drainage Analysis

2009-06-29T15:13:00.000-07:00

Ygnacio Canal Storm Water Flood Study, Walnut Creek, CA Client: CCWD
The Ygnacio Canal is a loop canal in the Contra Costa Canal system that is located in the City of Walnut Creek, CA. The majority of the five mile canal length is a trapezoidal, concrete or asphalt lined channel, with depths ranging from 1.3 to 2.5 feet, and top widths from 5 to 7 feet. Portions of the Ygnacio Canal in Walnut Creek have been impacted by off-site drainage into the canal. Off-site drainage includes runoff from areas outside the canal right-of-way that have been directed into the canal for disposal. Dr. Lewandowski performed field investigations and identified off-site drainage areas that included direct discharge of runoff from major roadways, and sheetflow from an adjacent golf course. Other areas had potential overflow into the canal right-of-way during high rainfall due to lack of conveyance or storage capacity in offsite structures.

Pajaro River Watershed Study, Pajaro River Watershed Flood Prevention Authority, CA
The Pajaro River flooded large areas of Monterey, San Benito, Santa Cruz and Santa Clara Counties during 1995 and 1998, causing extensive and costly damage. The Phase 2 study included analysis of a number of different floodplain and channel improvements, with various levels of flood reduction. The goal was to allow comparison of the costs, impacts and benefits of each improvement, and to group improvements into alternatives that could provide flood protection from 100-year events. Dr. Lewandowski assessed improvements and reviewed the groups of alternatives for reduction of existing and future 100-year flooding areas. A large floodplain area known as Soap Lake was identified as crucial to preventing increases in flood flows. In Phase 3, the Soap Lake floodplain area was modeled in HEC-GeoRAS to verify the floodplain limits that occur in storm events from 2-year to 100-year return periods. Dr. Lewandowski directed the modeling efforts and performed technical review of the modeling results. In Phase 4, he performed technical reviews of the installation of real time data transmission equipment at two proposed stream gage sites in the Upper Pajaro River watershed. He also reviewed the rating curve of the San Benito River at the Highway 156 stream flow gage.

Community Storm Water Drainage Studies, Cities of Cayucos and Nipomo in San Luis Obispo County, CA
Dr. Lewandowski provided review and analysis of existing flooding problems in the Cities of Cayucos and Nipomo, CA. Both communities had no formal drainage master plans, resulting in a number of minor flooding problems within the urban boundaries. In Cayucos, he identified locations where new installation of storm drain pipelines would allow conveyance of excess runoff to the outfall locations near the beach, instead of creating localized flooding of surface runoff. The Olde Town area of Nipomo had a number of flooding areas, caused by landowner encroachment along the creek and constricted crossings at roadway culverts. The roadway crossing culverts were assessed to determine whether County design standards for return period capacity were met. The Mesa area of Nipomo has an undulating surface, preventing development of a regional storm water system. Improvements were identified to reduce flood hazards caused by standing water in the roadways and to reduce the flood impacts to structures and residences.

Stream Management Master Plan, Zone 7 Water Agency, Alameda County, CA
Dr. Lewandowski developed technical memorandums and provided technical assistance in the analysis of flood control problems and needs for the stream management master plan. He reviewed a number of previous studies to identify needs and problem areas which needed further study. He also performed a hydraulic analysis of flooding along Arroyo de la Laguna and Arroyo Mocho using HEC-RAS.

San Juan Basin Surface Drainage Feasibility Planning, San Benito County Water District, CA
Dr. Lewandowski performed a review and analysis of previous hydraulic and flooding studies completed for the San Juan Basin to identify potential for developing a regional drainage system. Drainage options available with the cross-basin Highway 156 reconstruction were identified. The plan identified potential revisions to the Caltrans Highway 156 improvements that could improve drainage of both highway and local runoff. The plan also included potential projects that could be completed in the basin, with or without Highway 156 improvements, to reduce flooding in other areas. Following this preliminary assessment, the results were more widely distributed for comment and discussion. Further discussions with local agencies were performed to develop a more comprehensive understanding of drainage issues within the basin, and the potential need for funding of drainage improvements. From this work with local agencies, an action plan regarding storm water management in the San Juan Basin was developed. During the second phase, detailed field investigations were performed to identify the watershed boundary and potential sites for storm water detention basins.

Upper Penitencia Creek Floodplain Study, Santa Clara Valley Water District, CA
Dr. Lewandowski performed hydraulic analyses of a number of alternative bridge crossings and channel configurations for the King Road bridge crossing on Upper Penitencia Creek. The proposed bridge size was increased or paralleled with a box culvert to pass the 100-year flow. Downstream flow conditions included a potential widened overbank riparian area to convey the 100-year flow without flooding.

Calera Creek Floodplain Study, Santa Clara Valley Water District, CA
For Calera Creek, Dr. Lewandowski reviewed the expected water surface elevations under a number of different flow conditions to determine the channel capacity in each reach of the creek. The capacity was compared with the 100-year flow rate to determine where flooding would occur. Capacity limitations were observed near culvert crossings and at an energy dissipation drop structure.Green Valley Creek and Jameson Canyon Creek Hydrologic Studies– Cordelia, CA:Dr. Lewandowski led the hydrologic and hydraulic analysis of both creeks to determine peak flow rates expected near the Cordelia Junction along Interstate 80. He also trained staff on HEC-HMS program operation. Creek flows were calculated from a HEC-HMS model for each watershed to determine peak flow hydrographs. Rainfall patterns were based on the assumed maximum intensity rainfall rate at the middle of the storm, with stepped intensities on each side of the peak, which was different than previous hyetograph assumptions. Peak flow rates expected at the freeway crossings were compared with previous design values and actual capacity of existing culvert crossing structures.

Suisun Creek Floodplain Study near Interstate 80 – Fairfield, CA
As project manager, Dr. Lewandowski led the hydraulic analysis of the flooding that caused overtopping of Interstate 80, and developed options to prevent its reoccurrence. Peak flooding in this area is a result of local runoff and overbank flow from Suisun Creek. Creek overflows were combined with runoff developed from a HEC-HMS model for watershed to determine peak flow hydrographs. A HEC-RAS model was developed for flow overtopping the freeway, and results were integrated into the HEC-HMS model to determine upstream flooding and flood flow attenuation in the area. Modeled alternatives including a potential upstream detention area created by a proposed roadway crossing, and a grade elevation increase of I-80 to prevent overtopping.

San Pablo and Wildcat Creeks Floodplain Assessment, San Pablo, CA
FEMA had proposed revisions to the City of San Pablo’s Flood Insurance Rate Map (FIRM) that included significantly greater flooding areas compared with previous mapping. The revised boundaries included a total of 340 acres in the floodplain, with an additional 1,200 homes included in the floodplain area. As project manager, Dr. Lewandowski reviewed the Preliminary FIRM boundaries and results of the HEC-2 and HEC-RAS models for both San Pablo Creek and Wildcat Creek prepared by FEMA. He also revised the models to include reductions in Manning’s n values, recent channel improvements and bridge modifications, and an updated topographic map with 2-foot contours. After the adjustments, the floodplain developed from the revised model included only 140 acres, a reduction of 60 percent from the preliminary FIRM values. He assisted the City with their appeal of the FEMA preliminary FIRM. The revisions have been accepted by FEMA and will be included in the future map.

West Branch Alamo Creek Floodplain Study, Alameda County, CA
A floodplain study of the West Branch of Alamo Creek was performed for the Gale Ranch Development. The West Branch of Alamo Creek is a fairly small and narrow channel on a wide floodplain. The channel has emergent vegetation that has higher Manning’s n value than the drier adjacent overbank areas. The HEC-RAS computer model was used to model 2-year, 10-year, and 100-year flood flows. Comparison of existing condition flows and post-development flows were made to determine the impacts of the development on flooding and to identify potential locations for detention basins.

Collier Canyon Creek CLOMR, Livermore, CA
A storm water bypass consisting of parallel 72 inch diameter and 78 inch diameter pipelines was constructed for the Collier Canyon Creek in North Livermore. Dr. Lewandowski developed models for both the creek and the bypass pipelines for use in development of a CLOMR for the project. Channel flows were reduced by the bypass, causing the 100-year floodplain boundary to lie within the channel banks. The pipelines flows were modeled using PCSWMM, which allowed for partially full pipeline flow in the steeper sections of the parallel pipes. The natural creek channel was modeled using HEC-RAS, with flow boundary conditions developed on an iterative basis, depending on the flow rates in the bypass pipeline. Dr. Lewandowski worked directly with FEMA staff to finalize the modeling issues and resolve the CLOMR application issues.

Agua Fria Creek Relocation Analysis for Warren Avenue Grade Separation, Fremont, CA
Dr. Lewandowski was project manager for the hydraulic analysis of two large supercritical flow channels that were relocated to allow construction of a roadway undercrossing of a railroad right of way. Preliminary hydraulic calculations were performed to determine approximate slopes, channel widths, and superelevation at channel curves to prevent flooding at the 100-year flow rate. The channels were a combination of rectangular open channel and culvert flow. Transitions between the rectangular and existing trapezoidal channel and the junction of the two supercritical flows were designed to prevent formation of hydraulic jumps. A HEC-RAS model was developed to verify channel flow conditions and water surface profiles.

Mission Bay Development Flooding and Storm Drain Analysis, San Francisco, CA
Dr. Lewandowski was the project manager for hydraulic modeling of 100-year runoff and overland flows for portions of the Mission Bay project. He developed drainage scenarios and supervised the development of HEC-RAS models for sections of the development. Many of these models involved shallow flow depths in streets and limited discharge locations. Based on model results, the street designs and grades were modified to prevent water surface elevations from flooding the building footprint boundaries.

Agua Caliente Creek Floodplain Model, Fremont, CA
Dr. Lewandowski was project manager for this creek modeling study. A project site adjacent to Aqua Caliente Creek was planned for development, and the 100-year FEMA floodplain boundary was identified along the edge of the site. Dr. Lewandowski performed a hydraulic analysis of the existing creek using HEC-RAS to determine the approximate 100-year water surface for comparison to the finished elevations of the site. Preliminary drainage calculations for the project site were also completed to identify building pad elevations and approximate sizes of storm drains.

Home Depot EIR Hydraulics Review, Watsonville, CA
In development of the EIR for this project, Dr. Lewandowski performed review of the hydraulic calculations for drainage and water quality. He also developed a memorandum for the City recommending the value of the runoff coefficients that should be used in the project. He also wrote sections of the draft EIR and responded to public comments.

Southfront Road Trunk Storm Drain Analysis, Livermore, CA
Dr. Lewandowski was the project engineer for the analysis of a new trunk storm drain to replace the existing discharge into the Caltrans I-580 ditch and right-of-way. As-built drawings were reviewed and a SWMM model was constructed for the trunk drain to determine the required size and slope of each section of the storm drain.

Crystal Springs Reservoir Sedimentation Basin Predesign, San Francisco, CA
Dr. Lewandowski served as project engineer for the Upper Crystal Springs Reservoir sedimentation basin conceptual design. In this project, the Habitat Improvement Plan identified the previous sedimentation basin as future habitat for two endangered species. A new basin was relocated in a grassland area, and designed to collect sediments from the creeks discharging into the existing basin.

Drainage and Water Quality Studies, Los Angeles International Airport, Los Angeles, CA
These studies were completed as part of the CEQA/NEPA effort to determine impacts of the planned airport expansion. The potential for flooding created by the planned expansion was compared with the existing flooding at the airport. Dr. Lewandowski was project engineer for the drainage and water quality analyses.

San Elijo Lagoon Tidal Hydrodynamic Model, San Diego County, CA
Dr. Lewandowski has developed a hydrodynamic model for the San Elijo Lagoon, a 500-acre tidal wetland in Northern San Diego County, California. Model simulations included tidal flow movements under restoration scenarios selected to maintain natural tidal action in the lagoon. The software ESTFLO was used, and the code was reviewed and modified for model formulation. The project included delineation of wetland slough channels and heavily vegetated overbank flow areas. Vegetation resistance formulations utilized in the model were based on dissertation research. Existing field data was reviewed and implemented in the model calibration.

Storm Drain Modeling and Master Planning, Sacramento, CA
As project engineer, Dr. Lewandowski used the SWMM model to simulate storm water runoff for a 150-acre watershed comprising both open channel and conduit flows. He also char¬acterized and modeled alternatives to meet city standards for flood elevations in the street during the 10- and 100-year rainfall events.

Groundwater

2009-06-29T15:12:00.000-07:00

Oakwood Lake Groundwater Modeling Technical Review, Manteca, CA
Client: Aquatic Environments.Oakwood Lake in San Joaquin County, CA is a reclaimed sand mine pit that is proposed as a lake feature in a new development which will surround the lake. Dodson Engineers performed a technical review for the “Report of Transient Groundwater Modeling of the Oakwood Lake Area” by Condor Earth Technologies, Inc. as a quality control/quality assurance measure. The report evaluated the lake pool elevations and emergency flood control pumping needed for the proposed Oakwood Lake development. Dodson Engineers also reviewed the groundwater model developed for the surrounding area which determined groundwater movement and levels during a two year dry period, an average rainfall period, and a two year wet period the report. Rough estimates of flow using the Dupuit equation were used to verify groundwater flows into the lake. Potential stormwater impacts were also noted.

Groundwater Assessment for the Broadview Water District, Firebaugh, CA
Dr. Lewandowski assisted with the analysis of groundwater resources in the Broadview Water District for an environmental assessment of a reassignment of the District’s surface water supply contract to another agency. The project included evaluating the groundwater conditions both before and after land acquisition by the other agency. Two options were reviewed; continued farming (same as existing) and fallowing of the land. He reviewed the surface water delivery system and drainage collection system and summarized the quantity and quality of groundwater resources within the District. He also identified potential impacts of the water supply reassignment on the groundwater within the region.

Groundwater Management Plan, Stanislaus and Tuolumne Rivers Groundwater Basin Association, CA
Dr. Lewandowski assisted with development of a groundwater management plan for the Stanislaus and Tuolumne Rivers Groundwater Basin Association basin. The association comprised six members, including three cities, two irrigation districts, and the county. The plan work included review of data held by each of the members and identification of management impacts of twelve separate elements posed in current groundwater management legislation. He managed an agricultural and hydrogeology subconsultant, and provided data gathering assistance and leadership in urban groundwater management issues. The project included a public workshop for consensus building regarding groundwater management issues and options.

Groundwater Supply Assessment, City of San Diego, CA
Dr. Lewandowski was part of a four-member task force convened to identify the options for groundwater use by the City of San Diego, CA. The task force identified past, current and potential uses for each of the eight groundwater basins and formations near the City, as well as follow up steps to move the City forward in making best use of their groundwater resource as part of the overall water supply plan.

Well and Membrane Treatment System, Jordan Valley Water Conservancy District, UT
Dr. Lewandowski was project engineer for a groundwater extraction and treatment system for the Jordan Valley Water Conservancy District in Utah. The system involved the extraction of groundwater from eight to ten wells, with conveyance to membrane treatment plants for ultimate discharge into the municipal distribution system. The analysis included the sizing of distribution pipelines and selection of the location and total number of treatment plant sites. Hydraulic conditions were developed for each of the alternatives. A cost analysis included the capital and replacement costs of pipelines and treatment plants and the operating costs for power, chemicals, and membrane replacements for 50 years.

Hydraulic Analyses & Studies

2009-06-29T15:11:00.000-07:00

Contra Costa Canal Hydraulic Study, Contra Costa Water District, Concord, CA
Dr. Lewandowski performed a hydraulic study of the Contra Costa Canal to identify the current channel capacity and potential for flow constraints at channel siphons and check structures. The study included analysis of the unsteady flow in the tidally influence earth lined canal section, and the steady flow capacity in the concrete lined sections downstream of Pumping Plant 1 using HEC-RAS. Field tests were done to determine the Manning’s n value for the concrete lined sections and culverts in the earth lined sections. A post performance tool was developed to summarize the results of the modeling and to provide a graphical comparison of canal capacity with expected flow delivery rates through 2050.

South Bay Aqueduct (SBA) Hydraulic Capacity Study, Zone 7 Water Agency, Alameda County, CA
Dr. Lewandowski assisted the Zone 7 Water Agency in Alameda County with a hydraulic analysis of the existing South Bay Aqueduct as part of the raw water conveyance study. This work determined the design capacity, current capacity, and necessary modifications to the aqueduct to provide adequate capacity for future additional flows. Hydraulic testing was performed on portions of the canals and piping of the SBA to determine current head loss conditions. The backwater conditions measured in each canal section were used to determine the current Manning’s n values for the canal sections. Reviewing operating records of the SBA, he determined that Manning n values of the concrete lined channel were forty percent higher than design values. He assisted in development of alternatives to increase the aqueduct capacity, including replacement and paralleling of pipelines, raising the canal lining, relining pipelines to reduce the friction factor, and increasing the operating head.

Hydraulic Analysis of the Upper Diamond Fork Project, Central Utah Water Conservancy District
Dr. Lewandowski performed hydraulic calculations and assisted with the hydraulics design report. This design-build project included a flow transition connection to an existing 660 cfs flow discharge structure; a vertical 600 foot, six foot diameter shaft discharging to an underground flow control chamber; a five mile length, 10.5 foot diameter tunnel with an access and overflow structure; and 4000 feet of 96-inch diameter pipe. Challenging hydraulic situations included side flows over weirs, a channel transition from the tunnel to a rectangular channel that created supercritical flow, and a hydraulic jump forced by a drop in channel bottom elevation at the overflow structure.

Collier Canyon Creek CLOMR, Livermore, CA
A storm water bypass consisting of parallel 72 inch diameter and 78 inch diameter pipelines was constructed for the Collier Canyon Creek in North Livermore. Dr. Lewandowski developed models for both the creek and the bypass pipelines for use in development of a CLOMR for the project. Channel flows were reduced by the bypass, causing the 100-year floodplain boundary to lie within the channel banks. The pipelines flows were modeled using PCSWMM, which allowed for partially full pipeline flow in the steeper lengths of the parallel pipes. The natural creek channel was modeled using HEC-RAS, with flow boundary conditions developed on an iterative basis, depending on the flow rates in the bypass pipeline. Dr. Lewandowski worked directly with FEMA staff to finalize the modeling issues and resolve the CLOMR application issues.

Agua Fria Creek Relocation Analysis for Warren Avenue Grade Separation, Fremont, CA
Dr. Lewandowski was project manager for the hydraulic analysis of two large supercritical flow channels that were relocated to allow construction of a roadway undercrossing of a railroad right of way. Preliminary hydraulic calculations were performed to determine approximate slopes, channel widths, and superelevation at channel curves to prevent flooding at the 100-year flow rate. The channels were a combination of rectangular open channel and culvert flow. Transitions between the rectangular and existing trapezoidal channel and the junction of the two supercritical flows were designed to prevent formation of hydraulic jumps. A HEC-RAS model was developed to verify channel flow conditions and water surface profiles.

San Pablo and Wildcat Creeks Floodplain Assessment, San Pablo, CA
FEMA had proposed revisions to the City of San Pablo’s Flood Insurance Rate Map (FIRM) that included significantly greater flooding areas compared with previous mapping. The revised boundaries included a total of 340 acres in the floodplain, with an additional 1,200 homes included in the floodplain area. As project manager, Dr. Lewandowski reviewed the Preliminary FIRM boundaries and results of the HEC-2 and HEC-RAS models for both San Pablo Creek and Wildcat Creek prepared by FEMA. He also revised the models to include reductions in Manning’s n values, recent channel improvements and bridge modifications, and an updated topographic map with 2-foot contours. After the adjustments, the floodplain developed from the revised model included only 140 acres, a reduction of 60 percent from the preliminary FIRM values. He assisted the City with their appeal of the FEMA preliminary FIRM. The revisions have been accepted by FEMA and will be included in the future map.

LAVWMA System Capacity and Storage Assessment, Dublin, CA
Dr. Lewandowski served as project engineer for an analysis of the existing system capacity for the Livermore-Amador Valley Water Management Agency (LAVWMA). This project involved development of models for the existing wastewater treatment, storage and disposal systems to identify the limiting Average Dry Weather Flow (ADWF) that can be accommodated in the existing system. Three separate models were developed to show the limitations of storage operations at the treatment plants and at the pump station. He also developed an innovative methodology to determine maximum wastewater storage needs from a combination of collection system characteristics and the rainfall intensity curves for the area.

Drainage and Water Quality Studies for Los Angeles International Airport Expansion, Los Angeles, CA
These studies were completed as part of the CEQA/NEPA effort to determine impacts of the planned airport expansion. Dr. Lewandowski was project engineer for the drainage and water quality analyses. The potential for flooding created by the planned expansion was compared with the existing flooding at the airport. Alternatives were reviewed using existing airport facilities to mitigate increases in peak storm flow and storm water pollutants.

Hydraulic Analysis of Water Storage Tank Failure, Simi Valley, CA
For the Calleguas Municipal Water District in Simi Valley, CA, Dr. Lewandowski performed hydraulic calculations related to the catastrophic release of water from a 5 MG water storage tank. Earthquake failure scenarios were reviewed, to determine the potential variation in types of failure and consequent release of water from the tank, and potential safety issues for operators in the area. Possible flow paths and flood flow routing procedures were used to determine the flow rates leaving the site, and the flooding levels in relation to the operational areas and pumping equipment. Revisions in the yard design were proposed to reduce the peak flow leaving the site.

Filter Bed Flow Distribution Hydraulic Analysis, San Francisco, CA
Dr. Lewandowski was the Project Manager for a computational fluid dynamics (CFD) analysis of the filter gullets at the Harry Tracy Water Treatment Plant in San Francisco. Non-uniform distribution of flow from the gullet between filter beds was the suspected cause of observed gravel movement in the filter beds. Baffles were proposed to provide more uniform flow distribution. Dr. Lewandowski reviewed normal filter operations and three types of backwash conditions, and identified hydraulic conditions for each case. Two types of baffles, a cross-flow baffle and a bracket baffle, were analyzed. CFD results indicated the installation of the baffle would greatly improve the uniformity of flows from the gullet.

Fish Ladder and Water Plant Intake Predesign, San Jose, CA
Dr. Lewandowski was involved in the pre-design of a fish ladder on a dam at Saratoga Creek for the San Jose Water Company. The ladder pool sizes were obtained from consultations with DFG staff, and the spillway configuration was set to allow the fish to enter the ladder from a safe pool. Since the intake for a water treatment plant was located along the side of the ladder path, fish screens were necessary to allow safe passage of fish during periods of treatment plant withdrawals.

Moorpark Water Pump Station Predesign, Simi Valley, CA
In the predesign of the Moorpark Pump Station for the Calleguas Municipal Water District in Simi Valley, CA, Dr. Lewandowski developed the system head curves and pump curves for the pump station. Operational procedures included a number of different pumping scenarios to both low and high heads, with varied flow rates, and use of a pressure reducing station to reduce pump discharge head. Variable speed drives were added to the pumping units to meet the wide range of operating heads and flow rates. He also assisted in development of the pump station layout.

Pumping and Piping Studies & Designs

2009-06-29T15:10:00.000-07:00

Lockwood Siphon Rehabilitation Study, Pleasant Hill, CA Client: CCWD
The Lockwood Siphon is located along the Contra Costa Canal in Pleasant Hill, near the intersection of Pleasant Hill Road and Gregory Lane. The siphon conveys water through a low lying area near Grayson Creek. The siphon is approximately 1,800 feet in length with an inside diameter of 62 inches. The design capacity of the canal in this section is 102 cfs. Dr. Lewandowski performed a cost effectiveness evaluation for the rehabilitation of the Lockwood Siphon, comparing costs of annual lost water with cleaning and repair costs. The approximate water loss during normal flow conditions was estimated by stream gaging type measurements. The cost of the lost water over a 50 year period was compared with the potential repair costs to ensure a cost effective project. Specifications were developed for dredging of the sediments from the siphon and the repair of potential separated joints and longitudinal cracks along the siphon.

Untreated Water Pipeline Routing Study, Zone 7 Water Agency, Alameda County, CA
Dr. Lewandowski performed a routing study for the proposed In-Valley conveyance pipeline. This pipeline would be used to convey water from the Chain-of-Lakes to the vineyard areas in the southern portions of Livermore and to the SBA, freeing capacity within the South Bay Aqueduct. Altamont Water Treatment Plant Siting Study, Zone 7 Water Agency, Alameda County, CA Dr. Lewandowski was project engineer for the screening of the Altamont water treatment plant sites. The site evaluation and screening for the proposed Altamont plant included a review of engineering, operations, geotechnical, and environmental criteria for ten separate sites. By comparing issues related to each site, four were selected for further analysis and screening in the EIR process.

Multi-Purpose Pipeline Routing Study, Contra Costa Water District, CA
Dr. Lewandowski has performed a pipeline routing study which included five optional routes for a multi-purpose pipeline planned for the Contra Costa Water District. The District conveys water from the Delta to Central Contra Costa County by a canal passing through the water service area. The multi-purpose pipeline was proposed to parallel approximately twenty miles of the canal to provide additional reliability for water supply in the event of canal failure and to meet capacity needs of the district. The five potential routes included two within the canal right of way, two within surface streets, and one along the railroad right of way. Construction cost estimates for each route were developed, and an environmental assessment was performed for each route.

Moorpark Water Pump Station Predesign, Simi Valley, CA
In the predesign of the Moorpark Pump Station for the Calleguas Municipal Water District in Simi Valley, CA, Dr. Lewandowski developed the system head curves and pump curves for the pump station. Operational procedures included a number of different pumping scenarios to both low and high heads, with varied flow rates, and use of a pressure reducing station to reduce pump discharge head. Variable speed drives were added to the pumping units to meet the wide range of operating heads and flow rates. He also assisted in development of the pump station layout.

Well and Membrane Treatment System, Jordan Valley Water Conservancy District, UT
Dr. Lewandowski was project engineer for a groundwater extraction and treatment system for the Jordan Valley Water Conservancy District in Utah. The system involved the extraction of groundwater from eight to ten wells, with conveyance to membrane treatment plants for ultimate discharge into the municipal distribution system. The analysis included the sizing of distribution pipelines and selection of the location and total number of treatment plant sites. Hydraulic conditions were developed for each of the alternatives. A cost analysis included the capital and replacement costs of pipelines and treatment plants and the operating costs for power, chemicals, and membrane replacements for 50 years.

Land Disposal Facility for Wastewater Effluent, Washoe County, NV
Dr. Lewandowski was project engineer, supervising technical staff in design of pump station and wheel-move irrigation units necessary for disposal of treatment plant effluent at the CDB irrigation facility in Washoe County, Nevada. The project included an analysis of power and piping cost tradeoffs under various piping layouts.

Pipeline Protection at Creek Crossing, Alameda County, CA
Dr. Lewandowski was project engineer for the analysis of measures to protect a pipeline adjacent to a streambed in the Alameda Creek/Calaveras Creek Erosion Study. Flood flows during a peak storm event caused erosion of the backfill of a raw water pipeline constructed adjacent to the Calaveras and Alameda Creeks. Dr. Lewandowski developed and reviewed methods to protect the pipeline location and to prevent further erosion of these areas during future flood events, including stream training structures and riprap coverings.

Wastewater Treatment Plant Headworks Design, St. Peters, MO
Dr. Lewandowski performed detailed design of the headworks building at the St. Peters, Missouri wastewater treatment plant. Design included a screw-type pump station with debris removal by rotating arc bar screen and Pista-type grit removal system. He was also responsible for specification of equipment necessary for operation of the headworks.

Sediment Transport Studies

2009-06-29T15:09:00.000-07:00

South Bay Aqueduct Expansion Sediment Study Client: Zone 7 Water Agency
Dr. Lewandowski performed a study of the sediment conditions in the Bethany Reservoir and the South Bay Aqueduct (SBA), as well as potential changes in sediment conditions that may occur with the proposed Stage 3 pump expansion and Dyer Reservoir on the South Bay Aqueduct. The potential feasibility of other sediment management projects in the South Bay Aqueduct system was also reviewed, including the Dyer Reservoir and Stage 3 pumping operations to minimize sediment resuspension, management of Bethany Headlands sediment loads to reduce incoming sediment, dredging of South Bay Pumping Plant intake area to remove settled sediment and to prevent resuspension, and an underwater berm at South Bay Pumping Plant Forebay channel entrance to block sediment movements into the channel. The study was focused on the assessment of sediment related turbidity and the impact to water quality in the South Bay Aqueduct conveyance system. It was conducted to supplement environmental planning for both conceptual design and desired operating conditions at a new Altamont Water Treatment Plant. The study included analysis of the sediment size distribution along the reservoir floor based on sieve and hydrometer testing of sediment sizes, the review of flocculation testing and settleable solids testing to determine approximate deposition rates under various water salinity conditions, the tracking of turbidity spike movement and attenuation through the reservoir and the South Bay Aqueduct system, and the calculation of critical shear stress in the South Bay Pumping Plant Forebay Channel portion of the Bethany Reservoir.

Technical Review of San Benito and Pajaro River Sediment StudiesClient: RMC Water and Environment
Dr. Lewandowski performed a technical peer review of three sediment studies for the San Benito and Pajaro Rivers prepared by Philip Williams and Associates (PWA). In an assessment of the sediment transport characteristics of the Pajaro River flooding plan, the sediment dynamics of the existing condition and several alternatives were conceptually evaluated using a 2-dimensional coupled hydrodynamic and sediment transport model using MIKE-21C software. The sediment transport impact of the proposed benching concept for floodplain restoration was assessed. The simulation along a double meandering reach was performed for identification of conceptual volumes of erosion and deposition expected along other parts of the river. A second study included a simulation of a portion of the San Benito River to assess potential sediment inputs into the Pajaro River at their confluence. A HEC-6T model was used for simulation of the reach, and total the deposition or erosion characteristics of the reach segments were identified. In a third study, the use of a sediment trap on the Pajaro, constructed as a cutoff between two meanders bends was modeled using HEC-6T. Depositional problems in the main channel after the trap construction proved this sediment control strategy should not be used.

Crystal Springs Reservoir Sedimentation Basin Predesign, San Francisco, CA
Dr. Lewandowski served as project engineer for the Upper Crystal Springs Reservoir sedimentation basin conceptual design. In this project, the Habitat Improvement Plan identified the previous sedimentation basin as future habitat for two endangered species. A new basin was relocated in a grassland area, and designed to collect sediments from the creeks discharging into the existing basin.

San Francisco Bay Bridge Storm Water Sediment Study, Caltrans District 4, CA For Caltrans
Dr. Lewandowski led a review of the types and levels of contaminants measured in sediment size fractions collected in the drain inlets of the San Francisco Bay Bridge. These sediments were assumed to be typical of storm water pollutants in bridge runoff. This study included a literature review of bridge and highway sediment quality information throughout the US and Canada. The study was used to identify the types of runoff controls and the type of storm water treatment necessary for the new span of the bridge.

Assessment of Nonuniform Sediment Size Movement in StreamsClient: US Geologic Survey
Dr. Lewandowski performed flume analyses and settling analyses for the study and development of mathematical models for describing movements of nonuniform sediment sizes in stream beds. One flume analysis measured the movement of a band of sand sediment sizes along a gravel bed at different flow rates. A second flume analysis tracked the movement of gravel-sized, paint-tagged tracer particles along the gravel flume bed. Sand particle penetration of the gravel bed was estimated by experimental procedures and equipment in which settling sand is deposited into a gravel bed condition. Size fractions of all sands and gravels were measured for comparison of sizes. Probabilistic methods were researched for analysis of particle bed penetrations, and assessment of particle passage probabilities was performed.

Storm Water Quality Studies & Analyses

2009-06-29T15:08:00.000-07:00

Storm Water Lagoons Treatment Capacity Evaluation, City of Milpitas, CA
Dr. Lewandowski performed the hydraulic analyses of three storm water lagoons within the City. He reviewed the City's storm water Master Plan and their HYDRA models to determine lagoon elevations at 10- and 100-year storm events, and variations in the normal lagoon operating levels between summer and winter operations. He identified the storage volumes available at each lagoon for peak flow shaving capacity. He assisted in development of treatment capacity estimates for the lagoon, and in development of options for use of the treatment capacity by trading with out of basin development.

Assessment and Mitigation of Construction and Development Impacts to Storm Water Runoff, Ventura County, CA
Dr. Lewandowski was project engineer for pollutant loading calculations for large land developments. For the water quality modeling of a 2800-acre development, he assisted with identification of pollutant loads for existing and developed land uses, and he reviewed model results. He also reviewed various Best Management Practices for reducing pollutant loadings to pre-development levels. Pollutant loadings during construction were also considered, as well as the presence of endangered species (Red Legged Frog) at the site.

San Francisco Bay Bridge Storm Water Sediment Study, Caltrans District 4, CA
For Caltrans, Dr. Lewandowski led a review of the types and levels of contaminants measured in sediment size fractions collected in the drain inlets of the San Francisco Bay Bridge. These sediments were assumed to be typical of storm water pollutants in bridge runoff. This study included a literature review of bridge and highway sediment quality information throughout the US and Canada. The study was used to identify the types of runoff controls and the type of storm water treatment necessary for the new span of the bridge.

Drainage and Water Quality Studies for Los Angeles International Airport Expansion, Los Angeles, CA
These studies were completed as part of the CEQA/NEPA effort to determine impacts of the planned airport expansion. Dr. Lewandowski was project engineer for the drainage and water quality analyses. The potential for flooding created by the planned expansion was compared with the existing flooding at the airport. Alternatives were reviewed using existing airport facilities to mitigate increases in peak storm flow and storm water pollutants. Storm Water Discharge Quality Characterization, City of Salinas, CA For the City of Salinas, Dr. Lewandowski developed the discharge characterization of the city's stormwater runoff for the Part 2 National Pollutant Discharge Elimination System (NPDES) stormwater permit application. The CDM Watershed Management Model (WMM) was used in estimating total pollutant loading from each of the land uses within the city. Pollutant loading was determined for each of the designated watersheds within the existing city boundary.

Storm Water Pollution Prevention Plan Development, CA
Dr. Lewandowski has developed storm water pollution prevention plans (SWPPPs) for transportation facilities and wastewater treatment plants. He was responsible for development of a SWPP for an airport and a bus terminal station in Fresno, California, and a wastewater treatment plant in Antioch, California. He also assisted in the development of the Ventura County Storm Water Permit for industrial and commercial activities. He identified best management practices and helped to develop checklists for inspections of businesses with industrial and commercial activities.

Treatment Plant Hydraulic Analyses

2009-06-29T15:07:00.000-07:00

Treatment Plant Hydraulic Analysis, East Bay Municipal Utilities District, CA
Dr. Lewandowski performed hydraulic calculations for modifications to two East Bay Municipal Utilities District plants. At one plant, an increase in weir trough heights was proposed to increase plant capacity. At another plant, the filtered water manifold was checked for sufficient capacity to meet higher peak flow requirements.

Penitencia Treatment Plant Storage Hydraulic Analysis, Santa Clara Valley Water District, CA
For the Santa Clara Valley Water District’s Penitencia WTP, Dr. Lewandowski identified necessary operational procedure and reservoir level control changes resulting from revised plant piping and use of storage. The plant storage was used as a clearwell hydraulic control to set the hydraulic grade in the distribution system as well as provide for flow during filter backwash.

Harry Tracy Water Treatment Plant Flow Analysis, San Francisco, CA
Dr. Lewandowski identified the causes of unequal flow distribution between plant processes at the Harry Tracy WTP in San Francisco CA, and proposed possible modifications to balance flows at the plant.

Pulgas Dechloramination System Hydraulic Analysis, San Francisco, CA
Dr. Lewandowski performed the system hydraulic calculations and hydraulic profile for the dechloramination system constructed at the Pulgas Pumping Station. The dechloramination system is a 2,000 ft length, 10 ft diameter pipeline designed to provide sufficient contact time for dechloramination before discharge of the water into Crystal Springs Reservoir. Minimal head loss was required at the control structures necessary to maintain full pipe flow in the system. Hydraulic analyses were also performed for the outlet channel to determine potential improvements necessary to prevent overtopping of the channel during peak flows.

Filter Bed Flow Distribution Hydraulic Analysis, San Francisco, CA
Dr. Lewandowski was the Project Manager for a computational fluid dynamics (CFD) analysis of the filter gullets at the Harry Tracy Water Treatment Plant in San Francisco. Non-uniform distribution of flow from the gullet between filter beds was the suspected cause of observed gravel movement in the filter beds. Baffles were proposed to provide more uniform flow distribution. Dr. Lewandowski reviewed normal filter operations and three types of backwash conditions, and identified hydraulic conditions for each case. Two types of baffles, a cross-flow baffle and a bracket baffle, were analyzed. CFD results indicated the installation of the baffle would greatly improve the uniformity of flows from the gullet.

Plant Capacity Study, Union Sanitary District, Union City, CA
Dr. Lewandowski was project engineer for a wastewater treatment plant capacity study for the Union Sanitary District in Union City, California. In this study, he developed operational procedures to test the maximum hydraulic capacity of the plant under conditions where peak daily flows were only approximately half of the peak design flows. He also assisted in process capacity test development and review of test results. The study has found that the plant has a greater physical capacity than designed, and has allowed the efficiency of individual process units in the plant to be greatly increased by changes in operation.

Treatment Plant Water Distribution System Improvements, San Jose, CA
As project engineer for a water distribution system modeling project, Dr. Lewandowski led the modeling effort for a 14 mgd supply, cooling and irrigation water distribution system at the San Jose water pollution control plant, San Jose, California. A field test was formulated and performed to provide system calibration information. Alternative methods to provide water service for a new treatment plant process were identified and modeled.

Wastewater Sampling and Waste Loading Assessment, Sacramento CA
Dr. Lewandowski reviewed industrial wastewater flows created by an alcohol processing plant operation and instituted a program to sample and measure appropriate waste streams. He critically reviewed and compiled wastewater sampling data for a mass balance of the waste loading within the plant. He also developed options for waste handling and treatment of oily process streams within the plant.

Operation and Maintenance Manual, Brentwood, CA
Dr. Lewandowski has written a plant operation and maintenance manual for operation of the headworks building, the chemical feed system, the secondary process, the plant water system, and the effluent discharge for the wastewater treatment plant expansion at Brentwood, CA.

Operation and Maintenance Manual, Harrisonville, MO
Dr. Lewandowski has written a manual for operation of the Complete Mix Activated Sludge (CMAS) treatment process used in the wastewater treatment plant expansion at Harrisonville, Missouri. He also wrote an operations and maintenance manual for equipment installed during the plant expansion.

Operation and Maintenance Manual, LAVWMA Pumping Station, Dublin, CA
Dr. Lewandowski has written a manual for operation of the LAVWMA Pumping Station and secondary storage basin at Dublin, CA. The pumping station was upgraded with additional capacity and influent control provision. An emergency overflow was also constructed with the pumping station upgrade.

Water System Master Planning

2009-06-29T15:06:00.000-07:00

Martinez Water Master Plan Update – Martinez, CA
Dr. Lewandowski was project manager for a Water Master Plan update for the City. The City’s raw water supply, water treatment capabilities, and treated water distribution system were assessed to ensure that projected water demands can be delivered through year 2020. The City’s distribution system includes eleven reservoirs and six pumping stations serving four pressures zones. Four additional hydropneumatic systems serve areas outside the pressure zones. Operating criteria were developed using City water system standards and proposed state requirements. Current and future water demands were estimated and allocated using land use designations from the General Plan. Historical peaking factors were calculated and design values selected. The Water Treatment Plant capacity, pumping station capacity, and reservoir use for each pressure zone were analyzed and compared against demand requirements to determine appropriate sizes for additional pumping and storage needs. The impact of the City’s peak water demand conditions on the water distribution system was determined by modeling. Transmission capacity and storage needs were identified and increased as necessary. Distribution system and pumping modification were identified to provide added redundancy. The update provided recommended improvements and estimated costs for capital improvement projects required for an adequate and reliable water supply.

Winters Water Distribution Master Plan – Winters, CA
Dr. Lewandowski assisted with technical review and development of distribution system improvements for the City of Winters master plan. The City currently draws groundwater for their supply. Fire hydrant testing was set up to determine pipe C values for calibration. Improvements necessary to provide maximum day plus fire flow conditions required both pipeline improvements and additional wells. Additional well studies were proposed to verify well operating conditions.

Burlingame Water Distribution Master Plan – Burlingame, CA
Dr. Lewandowski assisted with technical review and development of distribution system improvements for the City of Burlingame master plan. The planning approach involved altering the system inflow from the SFPUC from a constant pressure condition to a constant flow condition. Potential locations for additional required storage were identified and modeled. A reduction in the number of service zone and the simplification of system operation was proposed. The analysis included extended period simulation to determine the amount of turnover in the storage tanks.

Zone 7 Water Distribution Master Plan, Alameda County, CA
For the Zone 7 Water Agency, Dr. Lewandowski was project engineer on the distribution system hydraulic analysis and master planning of the various water supply alternatives. The distribution system analysis used the Zone 7 H2Onet model to determine pipeline sizing for the fourteen alternatives considered. System operations with varying groundwater and treatment plant supply capacities were modeled.

Water Distribution Master Plan, Mount Prospect, IL
In Mount Prospect, the city planned to remove its single elevated storage from service and needed to determine the operational changes required in the system. Dr. Lewandowski simulated maximum day, maximum hour, and storage replenishment flow conditions under anticipated future demands. He also determined locations and cost of necessary improvements to maintain adequate system operation at future demand conditions.

Water Distribution Master Plan, Coon Rapids, MN
At Coon Rapids, the improvements identified to meet future demands included raising the city's existing elevated storage tank. Dr. Lewandowski simulated maximum day, maximum hour, and storage replenishment flow conditions under anticipated future demands. He also determined locations and cost of necessary improvements to maintain adequate system operation at future demand conditions.

DERWA Recycled Water System Analysis, CA
As project engineer for the DERWA model updates, Dr. Lewandowski made a thorough review of the numerical model used for the distribution of recycled water. He has assisted in modeling of update simulations which include moving the storage tanks and creating a looped system. He has also identified where the existing model peaking factors may have underestimated the amount of storage needed for the system. Model simulations included review of the potential to downsize transmission pipelines by providing additional storage in the system.

Wastewater Master Planning

2009-06-29T15:05:00.000-07:00

Technical Review of Plant Capacity Management Alternative StudyClient: Central Marin Sanitation Agency
Dr. Lewandowski performed a technical review of the flow model relating wastewater plant inflows to rainfall amounts. He also reviewed the treatment plant hydraulic calculations and the proposed assessment of peak flow capacity in the process units. He directed modeling efforts to determine potential causes of the discrepancies between measured peak plant inflows and calculated peak inflows. By varying C values for force mains in the pumping and force main model, calculated flow values similar to the peak measured flows were obtained. The C values corresponding to the measured plant flows were researched and found to be similar to those measured in normal operating conditions for force mains.

Master Planning Model Selection, City of Roseville, CA
Dr. Lewandowski assisted with assessment of collection system modeling needs for the City. The City staff was interviewed regarding modeling needs and data availability. Software evaluations were made for three different models, and vendor demonstrations were performed for each. A compilation of data requirements and recommended next steps for master planning were developed for the City.

Collection System Master Plan and Overflow Analysis, City of Benicia, CA
Dr. Lewandowski was project engineer for the master planning analysis of sanitary sewer overflows that occurred in the City of Benicia during peak rainfall events. Using SWMM modeling results for the collection system, he assisted in development of conveyance, storage and treatment options for prevention of overflows. By using a combination of parallel trunk sewers, pump station improvements, and treatment in existing storage basins, a cost effective alternative was developed.

Wastewater Master Planning, City of San Jose, CA
Dr. Lewandowski assisted in technical review and quality control/quality assurance for the City’s downtown area sewer master plan.

Collection System Master Planning, City of Winters, CA
Dr. Lewandowski performed quality control/quality assurance and technical reviews for the City of Winters collection system master plan. He also assisted with assessment and allocation of wastewater flows.

Trunk Sewer Master Planning, City of Hillsborough, CA
Dr. Lewandowski created a spreadsheet model for the City of Hillsborough, California to quickly estimate changes in trunk sewer size which were possible under various collection system restoration scenarios.

LAVWMA System Capacity and Storage Assessment, Dublin, CA
Dr. Lewandowski served as project engineer for an analysis of the existing sys¬tem capacity for the Livermore-Amador Valley Water Management Agency (LAVWMA). This project involved development of models for the existing wastewater treatment, storage and disposal systems to identify the limiting Aver¬age Dry Weather Flow (ADWF) that can be accommodated in the existing system. Three separate models were developed to show the limitations of storage operations at the treatment plants and at the pump station. He also developed an innova¬tive methodology to determine maximum wastewater storage needs from a combination of collec¬tion system characteristics and the rainfall intensity curves for the area.

Water Resources Studies

2009-06-29T15:04:00.000-07:00

Urban Water Management Plan Update Client: City of Martinez
Dr. Lewandowski is preparing the Urban Water Management Plan Update for the City of Martinez. The plan update includes historical water use and future water use projections, as well as an assessment of current demand management and conservation measures. Future water supply during drought periods is also estimated, with identification of proposed measures to be implemented as part of the water shortage contingency plan.

Alameda Creek Watershed Salinity Sources Study Client: DERWA
Dr. Lewandowski performed a study of salt sources in the Alameda Creek Watershed. He completed a review of the background information regarding salt loading from the DERWA project and developed a technical memorandum describing salt management issues within the Alameda Creek Watershed. The study included a review of the groundwater and salt transport model of the area, and a description of the sources of salt and their relative magnitude. The current and proposed management practices for salt control in the basin were reviewed and summarized. Feasibility Study for Membrane Bioreactor Facility Water SupplyClient: DERWAUnder current contracted water supplies, DERWA is expecting a future shortfall in recycled water supply during the maximum month or maximum day as early as 2010. To alleviate this shortage, a number of water supply alternatives are being investigated. Dr. Lewandowski analyzed the potential costs and conditions for development of a satellite wastewater treatment plant in the Dougherty Valley to produce recycled water for distribution to DERWA customers. The proposed satellite treatment plant was a Membrane Bioreactor (MBR) facility, which uses membrane filtering to produce a high quality effluent within an extremely small plant footprint. Plant wastes would be returned to the trunk sewer currently conveying Dougherty Valley wastewater to the Central Contra Costa Sanitary District (CCCSD). Construction and operation cost estimates were performed for comparison with other DERWA recycled water supply alternatives.

CALFED Assistance to DWR, Sacramento, CA
Dr. Lewandowski was part of a team that assisted CALFED with a review of a possible decision making process to reach consensus on alternatives for the future water supply. He held one-on-one meetings with some of the stakeholders to ascertain issues that were most critical to the stakeholder. He performed an extensive review of the types of hydrodynamic and water quality modeling performed for the planning process and the individual models that were used in the water supply planning process. He then developed an overview of the modeling process, including its assumptions and limitations, to be included as part of the summary to the stakeholders.

Water Supply Master Plan, City of San Diego, CA
Dr. Lewandowski provided technical expertise to the City of San Diego staff in support of the city's water supply strategic plan. Included in this work was a review of local and regional water supply issues such as water demands, supply, and reliability. He assisted in the development and evaluation of local water supply options including purchase and treatment of water, conservation, reclamation, groundwater, reservoir utilization, and desalination. Using this information, he helped to develop presentations for a series of stakeholder workshops utilized to determine a preferred action plan for the city's water supply.

Watershed Sanitary Survey of Lake Merced, San Francisco, CA
Dr. Lewandowski was also project engineer for a Watershed Sanitary Survey for Lake Merced in San Francisco, CA. The lake has a greatly reduced watershed and is fed primarily by groundwater. It is surrounded by urban uses including a golf course and a shooting range. He was primarily responsible for review of water quality issues, including potential sources of contaminants. He reviewed the sanitary and storm sewers surrounding the lake to identify potential areas where overflows of these sewers could introduce contaminants to the lake.

Watershed Sanitary Survey of Modesto Reservoir, Modesto, CA
He was responsible for developing a watershed sanitary survey for the Modesto Reservoir. This former irrigation supply reservoir was to be a new source of drinking water for the City of Modesto, California. The survey was necessary to determine both the character and potential sources of contamination within the watershed. The watershed area encompassed more than 1,500 square miles and included four individual reservoirs and part of Yosemite National Park. The survey was complicated by the impacts of recreational use on the Modesto Reservoir. In addition, a sampling program was devised to monitor reservoir water quality.