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James W. Sewall


Environmental sciences

The Environmental Sciences group at Sewall works with government, industry and commercial clients to develop innovative solutions to managing water resources and water quality. Integrating staff across multiple disciplines, the group collaborates with our partners in academia, business, government and the nonprofit sector to conduct research, seek grant funding, and implement projects in stormwater and watershed management, water quality monitoring, and environmental assessment, planning and permitting. Our aim is to help clients adopt best practices and protocols that not only meet regulatory compliance and reduce liability and costs, but also incorporate the newest and best environmental technologies.

Stormwater Management

Pollutants and nutrients carried by stormwater--intermittant runoff that does not soak into the ground--are recognized as the leading cause of water pollution. Water quality impairments and flooding cost homeowners, business and municipalities millions of dollars in damage each year. Traditional stormwater practices that direct stormwater to streams or into constructed ponds, wetlands, or subsurface-engineered devices are expensive to install and maintain, and often don't do an adequate job of protecting water quality. In partnership with the regional experts at the University of New Hampshire Stormwater Center, Sewall engineers research, design and implement stormwater controls that cost less to install and maintain, have low environmental impact, and protect water quality to meet regulatory requirements. Our design strategies include low-impact design (LID) methods such as :

  • Reducing or eliminating impervious surfaces that generate stormwater
  • Disconnecting existing impervious surfaces from surface waters
  • Decentralizing treatment to eliminate expensive real estate for stormwater ponds
  • Designing low- or no-maintenance stormwater infiltration
  • Using porous pavement to eliminate standing surface water and ice and to reduce costs for road salt
  • Infiltrating runoff to reduce water temperatures for colwater fisheries
  • Eliminating standing water to reduce mosquito populations
  • Removing phosphorus in lake watersheds

We help our clients find creative financial solutions to funding stormwater programs, whether through securing grants or advising on the creation of a stormwater utility. Many communities across the US are addressing the challenges and costs of stormwater management through stormwater utilities, which generate funding through user fees. This is an untapped financial opportunity that is only now beginning to be pursued in New England.

Watershed Management

Sewall scientists and engineers guide clients in restoring and protecting watersheds and their related ecosystems through planning and management of water resources and their uses and in reducing the impacts of water pollution on waterways and wetlands. Staff in Environmental Sciences were instrumental in founding PEARL, an online database for Maine lakes ( and are integrally involved in the online watershed master planning process for the largest lake watershed in New Hampshire (

Site Design and Development

Site selection research, environmental assessment and wetland delineation are essential first steps to successful projects in site development, management, and restoration. Identifying site issues early in the land planning process expedites permitting, promotes low-impact site design and development, and protects valuable natural resources. To assist commercial and industrial developers, land management consultants, and owners of public and private lands, Sewall offers environmental site assessment, permitting design, and site development, management planning, and restoration solutions that integrate a broad range of services in engineering, geospatial, and natural resource consulting.

Integrated Services

Working closely with private- and public-sector interests, non-governmental agencies, and federal, state and local regulators, Sewall professional staff provide integrated services to address our clients' water resource needs:

  • Water quality chemical/biological monitoring
  • Water quality consumer confidence reports
  • Aquatic habitat assessment and mitigation
  • Vernal pool determination
  • Wetland delineation, functional assessment, restoration and mitigation
  • Total maximum daily load (TDML) modeling and reports
  • Stream crossing upgrades and fish barrier mitigation
  • Low-impact stormwater design
  • Stormwater utility planning and implementation
  • Watershed management plans; stream and habitat restoration
  • Lake water quality protection plans
  • Shoreline protection assessment and management
  • NEPA environmental assessments and impact statements
  • Forestland appraisal and inventory
  • Site selection research (significant aquifers/endangered species)
  • Phase I and Phase II environmental site assessments (ESAs)
  • Permitting for US Army Corps, USEPA, Maine DEP and LURC projects
  • Aerial photography, forest covertype and wetlands mapping
  • Soil mapping and inventories
  • GIS consulting, systems integration, and application development
  • Online databases and spatial data management solutions
  • Web services
  • Grant research, grant writing for client projects
  • Public meeting facilitation and community outreach
  • Strategic planning for projects with environmental components
  • Ecosystem services assessments (natural resource economics)
  • Climate change impact evaluation, planning or mitigation of water resources
  • Remote development "concept plans"


More Info

Climate & weather

Stormwater utilities (PDF)

Residential stormwater management (PDF)

Stormwater planning and stream crossing for municipalities (PDF)

Water/wastewater engineering

Forestry and natural resource consulting

Biomass facility resource assessment

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Scott Graham, PE
Vice President
207 478 9509

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