•  Environmental Site Assessments
•  Brownfields Redevelopment
•  RCRA/CERCLA/UST Investigations and Remediation
•  Aquifer Analysis/Groundwater Modeling
•  Construction Dewatering and Stormwater Discharge Permits/Stormwater Management Plans
•  Groundwater Monitoring
•  Wetlands Hydrology

Environmental Site Assessments

The transfer of property ownership also includes the transfer of any and all environmental liabilities associated with the property.  By performing a Phase I Environmental Assessment (ESA) the prospective owner can qualify for the “Innocent Landowner Defense” under the Comprehensive Environmental Response, Compensation, and Liability Act more commonly known as CERCLA.  DG&A has performed Phase I ESAs for commercial real estate interests, governmental entities and industrial concerns.  All ESAs are performed in compliance with ASTM 1527 requirements, as well as the US EPA “All Appropriate Inquiry” regulations.    DG&A Will Minimize Environmental Liability Associated with Redevelopment

In some cases the Phase I ESA will find “recognized environmental conditions” on or associated with the property resulting in the need for a Phase II ESA which involves intrusive investigation and sampling of environmental media.   DG&A has pioneered the use of cost effective field techniques such as direct push drilling technology and chemical field screening methods to reduce both the cost and turnaround time of chemical analyses.

RCRA/CERCLA/UST Investigations and Remediation

DG&A can investigate and remediate non-compliance issues and/or releases of hazardous substances under all environmental regulatory programs.  Active facilities are regulated under the RCRA regulations while non-active facilities and orphaned sites are typically regulated by CERCLA.  Underground storage tank facilities can often present hidden liabilities from leaking tanks.  DG&A has extensive experience and expertise in site characterization of soils, groundwater and soil vapors resulting from release of hazardous compounds to the subsurface.  Remediation or corrective action may include soil excavation, in-situ soil treatment, groundwater pump and treat or in-situ treatment technologies which will vary depending on the contaminant.

Colorado UST Consultantant Registration #5632

Aquifer Analysis/Groundwater Modeling  Return to Top of Page

Cost Effective Data Collection Programs using State-of–the-Art Techniques and Equipment

The understanding of aquifer parameters is critical to any construction below the groundwater table or remediation of contaminated groundwater.  To evaluate the volume, rate and direction of groundwater flow DG&A provides aquifer analysis services including pump testing, slug testing and groundwater monitoring.  Data can be used to develop numerical groundwater models enabling evaluation of simulated stress on the system such as drainage, dewatering and other pumping scenarios.  Models can be used to predict the impact on the groundwater flow regime resulting from modifications to the natural groundwater flow conditions.  DG&A has developed groundwater models on entire groundwater basins for large mountain developments and has also modeled small drainage and dewatering scenarios.

 

Construction Dewatering and Stormwater Discharge Permits/Stormwater Management Plans

DG&A has the experience and expertise to efficiently prepare permit applications under the Clean Water Act including construction dewatering discharge permits and stormwater discharge permits.  Stormwater Management Plans (SWMPs) are also required to support the construction stormwater permit.  The SWMP includes a description of the BMPs or Best Management Practices to control erosion and sedimentation and to prevent spills of fuels and other materials on the construction site that may impact water quality. Best Management Practices Improve Stormwater Quality from Construction Sites

BMPs include diversion ditches and berms, water quality detention ponds, erosion control features such as silt fencing, hay bales and erosion control matting.  DG&A also provides inspection services for the construction stormwater discharge required by the permits. Expert Stormwater Management Planning Will Eliminate Penalties under the Clean Water Act

Groundwater Monitoring  Return to Top of Page

Whether its baseline monitoring of groundwater levels, monitoring to evaluate the progress of remediation or monitoring for natural attenuation of contaminants DG&A has the capability to develop and implement groundwater monitoring plans for all situations.  With over 25 years of experience in sampling groundwater DG&A uses the latest technology, equipment and fully qualified laboratories producing defensible data of the highest quality.  All sampling procedures and protocols follow the current state and federal agency guidance.  Data can be stored and retrieved in one of several electronic data bases available depending on the customer’s needs and compatibility.

High Quality Monitoring Programs using the Latest Technology Provides Defensible Data

Wetlands Hydrology

Best Management Practices Improve Stormwater Quality from Construction Sites

DG&A has extensive experience in the investigation, characterization, and modeling of alpine wetlands groundwater hydrology in alpine environments.  The understanding of the natural groundwater flow regime is critical to the long term protection of alpine fen wetlands nourished by groundwater flow.  Development in mountainous areas with wetlands often requires studies to evaluate if wetlands will be impacted by changes in the natural groundwater flow.  DG&A has developed large numerical computer models of groundwater basins with extensive wetland complexes to assess the impact of development on flow to wetlands.  Mitigation scenarios were also modeled to simulate the reintroduction of diverted groundwater flows back to the affected wetlands.  These studies are typically performed in support of US Army Corps of Engineers 404 Wetland Permit requirements.

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