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Projects

Allterra has conducted complex remedial investigations, feasibility studies, and implemented Corrective Action Plans for hazardous material release sites throughout California. Below are a few Project Abstracts to demonstrate our expertise.

Monterey Peninsula Airport Project – Monterey, California

Groundwater Resource Planning

The Monterey Peninsula Airport (MPA) Project was part of the Monterey Peninsula Water Management District’s (MPWMD) Local Water Project Funding Program.  Allterra worked in collaboration with MPWMD and Monterey Peninsula Airport District (MPAD) to evaluate potential use of a former Groundwater Extraction and Treatment System located near the northern boundary of the MPA property.

The project had two phases:

  • Phase 1: Feasibility Investigation to determine Sustainable Groundwater System yield and identify potential users of the non-potable water supply; and
  • Phase 2: User Options Analysis where Allterra evaluated probable best uses of the water supply.

Phase 1

The first phase of the MPA Project involved preliminary system testing, aquifer property calculations, and analysis of potential well use options to help offset current demands for California American Water (Cal Am) resources in the Monterey Bay Region.

Based on our preliminary evaluation, Allterra estimated the current well network could provide approximately 34.3 million gallons of non-potable water per year with an estimated aquifer production longevity of 25.7 years (not including retrofitting existing injection wells).

Additionally, Allterra concluded there is a high level of interest and a significant future market potential for providing an alternative non-potable water source to customers looking to offset their current demand for Cal Am resources.

Allterra recommended additional analyses to determine the approximate value of water produced from the existing well system. Additionally, Allterra recommended further evaluating distribution options for this non-potable water including the design and construction of permanent conveyance pipelines to serve potential on- and off-site users.

Phase 2

Following completion of Phase 1, Allterra completed an Options Analysis to help determine best value for use of groundwater from MPAD’s groundwater system.

In our analysis, Allterra determined:

  • Water needs of potential users;
  • Estimated current market value of non-potable water;
  • Compared this type of project to other similar projects being implemented by other water agencies in the Monterey Bay area; and
  • Estimated the engineering and construction costs of a non-potable water distribution pipeline to serve potential on- and off-site users.

Based on our option analysis, Allterra estimated overall demand for non-potable water for on- and off-site user identified was an estimated 2,120,000 gallons per month and could be offset by the currently equipped three extraction wells located within the MPAD groundwater system whose combined yield is estimated to be  2,859,840 gallons per month.

The estimated market value of the MPAD’s water at the time was between approximately $0.0046 to $0.0067 per gallon.  Based on economic considerations, the best option for non-potable water use from MPA’s groundwater system appeared to be on-site users with construction of conveyance piping for distribution to onsite users.

Spartan Gas, South 4th Street – San Jose, California

UST Leak of Benzene and MTBE

Allterra was selected to investigate and remediate benzene and MTBE impacted soil and groundwater beneath an active gasoline station located in a residential neighborhood bordering San Jose State University. The Remedial Work was completed under the direction of the Santa Clara County District Attorney’s Office, Santa Clara County Department of Environmental Health, Regional Water Quality Control Board – SF Bay Region, and Santa Clara Valley Water District. Elevated levels of benzene and MTBE contamination and a large groundwater plume made the 4th Street fuel-leak case a priority for government agencies where a Court Ordered Injunction was levied with strict deadlines. Allterra had not worked on the project previously but was chosen to implement aggressive Corrective Action work scopes and meet court-imposed deadlines.

The project went as follows:

Allterra prepared a Corrective Action Plan to identify and evaluate remedial options to address contaminant source area and restrict down-gradient migration of high levels of dissolved benzene and MTBE.

We designed, permitted, and constructed a remediation system specifically for the Site and it’s groundwater and soil conditions. The system included three soil vapor extraction (SVE) wells, five groundwater extraction wells (GWE), and a dual-phase extraction (DPE) and treatment system. Key design challenges were installing the system at an active gas stations in downtown San Jose and having to utilize a series of horizontal borings beneath adjacent properties to access offsite extraction wells.

Construction and operation of the remediation system required permits from the following agencies:

  • City of San Jose Planning, Building, and Public Works Departments
  • Regional Water Quality Control Board – SF Bay Region (RWQCB)
  • Bay Area Air Quality Management District (BAAQMD), and
  • Santa Clara Valley Water District.

Allterra constructed the remediation system over a 3-month period in early 2005. Construction activities included installation of subsurface water and electrical lines, wellhead conversions, equipment installation, process plumbing, and installation of electrical controls and interlocks.

The remediation system operated continuously from 2005 to 2008. During that time, Allterra was responsible for:

  • Maintaining equipment;
  • Tracking DPE system performance data for contaminant mass removal and groundwater influence analysis;
  • Collecting vapor and water stream samples from the remediation system to ensure treatment effectiveness and permit compliance for discharging treated air and groundwater;
  • Document site activities, results, and recommendations in Monthly, Quarterly, and Annual Technical Reports for submittal to the Santa Clara County Department of Environmental Health, Regional Water Quality Control Board – SF Bay Region, and Bay Area Air Quality Management District;
  • And Preparation of Reimbursement Requests, on our clients behalf, to the Division of Financial Assistance of the California State Water Resources Control Board’s UST Cleanup Fund Program.

In 2016, the 4th Street Project was issued Case Closure; no further action is required at the site. Allterra was the last Environmental Consultant on the project. Multiple consultants worked on the project previously but none successfully implemented remedial action in the challenging urban environment of Downtown San Jose.

For specific project details, check out Geotracker case files here.

San Martin Tire – San Martin, California

UST Leak of Benzene and MTBE; Groundwater Recharge/Sustainable Remediation

San Martin Tire was a fuel-leak case project we inherited from a retiring geologist.  The Site Investigation phase was nearly complete and the Santa Clara County Department of Environmental Health and Regional Water Quality Control Board – SF Bay Region wanted to see Corrective Action taken.  Allterra was recruited into the project based on our track record of successful implementation of Corrective Action work scopes.  San Martin Tire site had elevated levels of benzene in groundwater immediately adjacent to the former UST location with domestic water supply wells down gradient from the Site.

As a first step, Allterra reviewed previous reports and analyzed previous data to get a conceptual understanding of site conditions. We then tested our ideas by proposing a series of remedial pilot tests to determine the best approach to mitigate soil and groundwater contamination beneath the property.

After pilot testing and data analysis, site conditions were better understood and Allterra prepared an Interim Remedial Action Plan to mitigate contamination and set a reporting schedule to document results.

Our system design called for one dual-phase extraction (DPE) well through source area and connecting three existing soil vapor extraction wells to the system.  The DPE well targeted source area, soil immediately adjacent to the former UST location that was inaccessible during the UST removal activities.  Down-gradient of the former UST location, three existing soil vapor wells were connected to the system to reduce potential for exposure to fuel impacted soil vapor gas.  Vapor intrusion is a common exposure pathway for fuel cases and can pose threats to human health.

Contaminated soil vapor and groundwater was extracted from wells and conveyed through piping to a treatment system designed to remove fuel contaminants in both dissolved and vapor phases.  Treated air was discharged to the atmosphere under Bay Area Air Quality Management District (BAAQMD) permit.  Treated groundwater was discharged to land under Regional Water Quality Control Board – Central Coast Region (RWQCB) permit (WDR Permit).

Discharging treated groundwater to land is rare.  Typically treated groundwater is discharged to a storm drain under State NPDES permit or a sewer drain under Local POTW permit.  Allterra was forced to think outside the box and develop an alternative since there was no storm or sewer infrastructure to utilize at the Site.  We ended up obtaining a Discharge to Land Permit from the RWQCB.  The Discharge to Land permit allowed us to discharge treated groundwater to an infiltration basin we designed and installed specifically for the site and soil lithology.

To date, Allterra processed over 100,000 gallons of contaminated groundwater and reduced contamination levels to the extent practical in soil and groundwater. Treated groundwater was discharged to an infiltration basin, returning extracted groundwater to the same aquifer, recharging groundwater after remediation.

The Interim Remedial Action Plan worked; contamination was reduced to the extent practical and formal Case Closure was granted in 2015.

For specific project details, check out Geotracker case files here.

Livermore Gas and Mini-Mart – Livermore, California

UST Leak of Benzene and MTBE; Municipal Water Supply Well near Site

Allterra was selected to investigate and remediate contaminated soil and groundwater beneath an active gasoline station located in Livermore, California. Investigation and remediation work was completed under the direction of the Alameda County Department of Environmental Health and the San Francisco Bay Regional Water Quality Control Board. Elevated levels of TPHg, TPHd, benzene, and MTBE were detected in groundwater down-gradient of the Site and immediate action was required to prevent the groundwater plume from coming any closer to a municipal water supply well located down-gradient.

A Corrective Action Plan was prepared by Allterra to identify and evaluate alternatives to remediate the contaminant source area and restrict down-gradient migration of high levels of TPHg, TPHd, benzene, and MTBE.

In order to implement the most effective remedial approach, Allterra performed remedial pilot testing using three on-site extraction wells as extraction points. Pilot scale remedial activities varied from SVE focused to more GWE focused as remedial performance data was gathered. Although significant contaminant mass removal was achieved through dual-phase extraction remedial activities, large fluctuations in local groundwater elevations made continuous system option unfeasible.  Another approach was needed given the regional fluctuation in groundwater elevation.

After pilot testing, we elected to use an in-situ treatment approach where oxygen-releasing compounds are injected in source areas.  Oxygen releasing compounds are intended to oxidize fuel compounds and introduce oxygen into the subsurface so natural processes, like bio degradation, can further reduce contaminant levels.

Allterra developed a remedial work-scope involving the pressure injection of two chemical oxidizing products designed to vigorously attack petroleum hydrocarbons in place. The area with the highest concentrations of petroleum constituents was laterally and vertically delineated by the collection of 65 soil samples and compilation of over 12 years of groundwater analytical data. Once the target area was defined in depth, width, and length, Allterra personnel supervised the mixing and injection of the oxidizing agents.

Since in-situ remedial work was completed, petroleum constituents in groundwater have exhibited substantial decreasing trends. The groundwater plume has significantly been reduced and MTBE has been reduced by 94% in the well with the highest historic concentration.

Given the success of Remedial Action, the project was issued Case Closure by Alameda County and SF Regional Water Quality Control Boards in 2016.

Allterra’s active approach to addressing contamination at it’s source translated into case closure and another successful example project.

For specific project details, check out Geotracker case files here.

Spartan Station – East Taylor Street, San Jose, California

Pay For Performance Program; UST release of Benzene and MTBE

Spartan Gas was another highly impacted site with MTBE and little progress on cleanup.  Allterra was brought in to implement Remedial Action immediately.

Again, Remedial Work was completed under the direction of the Santa Clara County District Attorney’s Office, Santa Clara County Department of Environmental Health (SCCDEH), Regional Water Quality Control Board – SF Bay Region, and Santa Clara Valley Water District. Elevated levels of benzene and MTBE contamination and a large groundwater plume made this case another priority for government agencies where a Court Ordered Injunction was levied with strict deadlines.

Allterra had not worked on the project previously but was chosen to implement aggressive remedial action work scopes, meet court-imposed deadlines, and complete all work under the SWRCB’s UST Cleanup Fund’s “Pay For Performance” Program, where payments were made upon achievement of contamination reduction milestones.

Allterra designed, permitted, built, and operated a dual-phase extraction system without receiving payment until it successfully operated and actively reduced contamination.

After 2 years, Allterra’s DPE system reduced contamination substantially; triggering the 100% completion cleanup milestone of the “Pay For Performance” Project.

Allterra is 1 of only 5 companies in California to complete a PFP Project.  444 was our second PFP project completed.

California’s pilot PFP program was part of the SWRCB’s UST Cleanup Fund and was  intended to revolutionize the environmental consulting field. Rather than pay consulting companies on a Time & Materials (T&M) basis for remediation work, the State decided that paying for results would be a better system. The PFP Program did just that by setting cleanup goals that had to be reached in order for the consulting company to be paid. There were 35 PFP projects implemented throughout California; only 5 achieved the 100% Completion Milestone (Allterra was responsible for 2).

During system operation, Allterra maintained equipment, collected vapor and water samples to ensure permit compliance, tracked system performance data, and prepared Monthly, Quarterly, and Annual reports for submittal to the SCCDEH, City Wastewater Control, and SF Bay Area Air Quality Management District (BAAQMD). Operation data was tracked and evaluated to immediately identify system inefficiencies and continuously optimize system performance.

After remediation, Allterra completed Tier 2 Risk Based Closure Analysis (RBCA) to evaluate the potential for residual contamination to impact the health of future on-site workers and down-gradient residents. The risk assessment involved evaluations of trends in hydrocarbon contamination in soil, soil vapor, and groundwater, comparisons with Tier 1 and 2 levels established by the RWQCB, and analysis of institutional and engineering controls implemented by a neighboring residential housing development.

In the end, reductions in contamination and elimination of exposure pathways resulted in Case Closure in 2015.

For specific project details, check out Geotracker case files here.

Former Beach City Gas – Santa Cruz, California

UST release of MTBE; Remediation and Site Redevelopment

Allterra was selected to oversee the removal of three 10,000-gallon gasoline underground storage tanks (USTs) during redevelopment of a former gasoline fueling station located at 1104 Ocean Street in Santa Cruz, California (Site). Elevated levels of petroleum constituents including total petroleum hydrocarbons as gasoline (TPHg) and MTBE were detected in soil and groundwater during UST removal activities.

Allterra oversaw all aspects of UST, dispenser, product piping, and impacted soil removal and disposal.  Shallow groundwater conditions on-site even required Allterra to extract groundwater from the UST excavation for treatment and eventual discharge under permit. Allterra removed fuel impacted soil and groundwater as part of the UST removal work scope. Additional corrective action work during UST removals was a key component to our plan to clean the site up.

Allterra also completed investigation and remediation work at the site once UST removal work was completed.  The groundwater plume was not fully delineated and a Corrective Action Plan to further reduce contamination was required by Santa Cruz County and Regional Water Quality Control Board.

Allterra prepared a groundwater investigation to fully define the groundwater plume and completed a Corrective Action Plan (CAP) for the site.

For corrective action, Allterra designed and built a groundwater extraction and treatment system (GWETS) that included four extraction wells that removed impacted groundwater from areas beneath the Site. Groundwater was treated using two granular activated carbon (GAC) vessels prior to discharge to the sanitary sewer under City of Santa Cruz permit.

During system operation, Allterra maintained equipment, collected water effluent samples to ensure permit compliance, tracked system performance data, and prepared quarterly reports for submittal to the SCCDEH and RWQCB.

The GWETS system was effective in removing TPHg and MTBE from the subsurface beneath and down gradient of the Site and current dissolved contaminate levels do not warrant further corrective action.

Allterra prepared a low-risk case closure evaluation for the Site to address any human health concern the State or County may have. The low-risk evaluation consisted of a review of historical investigative and corrective action work completed at the Site, a summary of current environmental conditions, and a low-risk screening using criteria established in the State Resources Control Board (SWRCB) resolutions and past Water Quality Orders (WQOs).

In the end, reductions in contamination and elimination of exposure pathways resulted in Case Closure in 2015.

For specific project details, check out Geotracker case files here.

Heating Oil Tank – Scotts Valley, California

In-situ Remediation of Soil; Limited access

Allterra investigated and remediated hydrocarbon-impacted soil and ground- water for a residential property located at 255 Northridge Drive in Scotts Valley, California (Site). An underground storage tank (UST) containing heating-oil was previously removed from the Site and petroleum impacted soil was found beneath the UST. Subsequent investigations revealed that impacted groundwater also existed below the UST.

The UST was located in a narrow area adjacent to the existing house at the toe of a steep hillside and presented numerous challenges to investigative and remedial efforts. Site investigation activities around the source area were carefully planned and facilitated using limited access drilling equipment.

Investigation and remediation work was completed under the direction of the Santa Cruz County Department of Environmental Health (SCCDEH) and the San Francisco Bay Regional Water Quality Control Board (RWQCB).

Allterra designed a site investigation work scope to fully delineate the lateral and vertical extent of petroleum impacted soil, soil gas, and groundwater in the immediate vicinity of the former heating-oil UST. Earth materials discovered via subsurface exploration consisted of heterogeneous alluvial soils mantling sandstone bedrock at relatively shallow depths. Groundwater was only encountered in three soil borings and suggested a continuous saturated zone did not exist below the site and groundwater only occurred in localized perched zones.

Understanding the hydro-geologic framework of the Site was essential since groundwater contamination was the primary concern of the State and County oversight agencies given shallow groundwater flow was the most probable mechanism of lateral contaminate transport from the source area. Structural analysis indicated that the soil bedrock contact was an irregular erosional surface with numerous hollows that collected groundwater intermittently throughout the year. Allterra concluded:

  •   Perched groundwater zones were not connected to regional groundwater and potential for contaminate migration off-site was low; and
  •   Soil, soil gas, and groundwater was adequately characterized and delineated horizontally and vertically to define a “target zone.”

After screening several remedial strategies, Allterra chose an in-situ remedial alternative involving the injection of oxidizing compounds into the subsurface to chemically attack petroleum hydrocarbons in place. Aquifer testing of soils in the “target zone” indicated that soils were too impermeable to facilitate the standard method of pressure injection of the remedial solution. Consequently, Allterra designed and built a passive injection system that utilized a network of seven temporary injection wells to gravity feed the remedial solution into the target zone.

The injection wells were screened at alternating depth intervals to ensure complete coverage throughout the vadose and phreatic zones. Following the application of the oxidizing solution, the injection wells were sealed using a cement made using an oxygen releasing compound that would act as a “polishing agent”, further reducing subsurface concentrations of petroleum hydrocarbons over time by enhancing natural biodegradation.

In the end, reductions in contamination and evidence the aquifer was disconnected and presented no exposure pathway enabled the site to be closed in 2015.

For specific project details, check out Geotracker case files here.

Jayleaf – Hollister, California

Compliance with Waste Discharge Requirements (WDR)

Allterra designed and implemented a data collection, monitoring and reporting program for Jayleaf Specialties’ (Jayleaf), a vegetable processing facility in Hollister, California. Site work was performed to comply with Waste Discharge Requirements (WDRs) outlined in the Central Coast Regional Water Quality Control Board’s (RWQCB) General Order No. R3-2004-0066.

On behalf of the client, Allterra negotiated a phased approach to comply with WDR requirements the RWQCB as requiring. Negotiating a compliance schedule and work scope was key to finding the most cost effective approach. Following initial data collection, further review of RWQCB General Order R3-2004-0066, and further discussions with the RWQCB, Allterra realized Jayleaf may qualify to transfer out of the General Order by accurately characterizing their facility’s operation.

To characterize Jayleaf’s operation and alleviate RWQCB concern, Allterra worked with Jayleaf to characterize the facility and prepare a report to the RWQCB.  Allterra sampled water entering the facility from a supply well, sampled effluent wastewater discharged to a disposal field, and installed a cold water totalizer to track water discharges. Data was used to determine total nitrogen and BOD loading rates in the disposal field, the main concern of the RWQCB.

To further address RWQCB concerns, Allterra suggested Jayleaf reduce overall chemical usage during vegetable processing operations to lower contaminant concentrations in effluent wastewater.

Site work and data collected was compiled into a report provided to the RWQCB. The report included a detailed summary of site conditions and observations, data collection and tracking, groundwater and wastewater sampling results, and conclusions and recommendations.

The report ultimately supported Jayleaf’s request to transfer out of the General Order they were enrolled in.  After collecting data and working with the Regional Board Jayleaf’s facility was re-categorized as a smaller facility and ongoing self-monitoring was sufficient to demonstrate groundwater was not being degraded.

Loch Lomand – Santa Cruz, California

Western Pond Turtle Habitat Conservation Planning

Allterra conducted a one-year study on the Western Pond Turtle (Actinemys marmorata) population at Newell Creek Reservoir (NCR) in Santa Cruz County. The purpose of the study was to develop a better understanding of the Actinemys population by examining habitat use and identifying potential threats to long-term viability.  The information we obtained was essential to the Habitat Conservation Plan developed by the City of Santa Cruz to apply for an Endangered Species Act Section 10 permit.

Capture and handling of turtles was conducted in accordance with our Scientific Collecting Permits issued by the California Department of Fish and Game.  We captured turtles in hoop traps and affixed small radio transmitters to adult Actinemys. Using radio telemetry, we monitored turtle activity for up to one year. We also surveyed woodland adjacent to the reservoir to identify the extent of potential  nesting habitat.

Geospatial data collected at turtle locations were analyzed in a GIS framework.  We calculated home ranges and movement statistics for each radio tagged turtle.  Spatial data were plotted on geo-referenced aerial photos of the study area to examine seasonal habitat use by turtles.  For comparative purposes, we performed a Habitat Suitability Analysis using California Wildlife Habitat Relationship criteria and available habitat information to assess the extent of reproductive habitat available to Actinemys.

Findings of this work were compiled into a final report provided to the Water Department of the City of Santa Cruz.  We provided an evaluation of the threats facing the Actinemys population at NCR and outlined several simple habitat modifications likely to bolster population levels in the future.  Additionally, we furnished a report to the Redwood Sciences Laboratory, a group commissioned by the California Department of Fish and Game to develop a conservation strategy for Actinemys in California.

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