Stormwater System Management,
Operation and Maintenance

Grace Environmental Services, LLC,  provides comprehensive stormwater management planning, design and implementation, Clean Water Act/NPDES compliance/permitting  support, erosion and sediment control planning/design, as well as watershed management and analysis services. The GES Team routinely works with public and private sector clients to prepare Stormwater Pollution Prevention Plans (SWPPPs), stormwater management plans (SWMPs), watershed management plans and drainage/stormwater treatment infrastructure designs.

The GES Team has significant experience in stormwater management. Our team is supported by in-house engineers and other team members who work with various cities and municipalities in identifying any stormwater issues, work to correct them, provide the necessary reports, as well as other permit oversight as needed.

The GES team works with the cities/municipalities in coordinating existing stormwater programs and compliance efforts and provides support on permit compliance requirements. Our Team can also assist with the preparation of any Notice of Intent, and Annual Updates to the Watershed Management Group. The GES Team is also prepared to support any updates to an existing EWWP and Green Streets Master Plan.

Stormwater Permitting & Compliance

The GES Team has developed stormwater designs and permit applications that have supported our clients in obtaining stormwater discharge permits associated with Municipal Separate Stormwater Systems (MS4) sites. Our stormwater permitting experience has ranged from stormwater retrofits and BMP implementation to finding solutions at contaminated sites and large industrial and institutional facilities. We have effectively navigated the complex CWA and NPDES regulations to satisfy federal and state stormwater management policies as well as local ordinances.

Our water resource engineers have collaborated to address our clients’ stormwater issues during both construction and operations of their developments and facilities. The GES Team stormwater consulting, engineering, watershed analysis and associated permitting services include:

  • Civil/Site Engineering Design
  • Hydrologic and Hydraulic Modeling
  • GIS Analysis and Mapping
  • Flood Assessments
  • Drainage Studies and Design
  • Pollutant Loading and TMDL Assessments
  • Stormwater Pollution Prevention Plans (SWPPP)
  • Stormwater Management Plans
  • Erosion and Sedimentation Control Plans
  • Biotechnical Erosion Control Design
  • Stormwater Best Management Practices (BMPs)
  • Low Impact Development (LID)
  • Municipal (MS4) Stormwater Compliance
  • NPDES Stormwater Permitting and Compliance
  • Stormwater Sampling
  • Stormwater Systems and BMP Operation and Maintenance Plans
  • Site/watershed soil stabilization planning and design

Innovative Approaches to Stormwater Control

The GES Team has considerable experience evaluating and implementing Low Impact Development (LID) measures and stormwater flow-control and water quality enhancement BMPs as well as in supporting watershed stabilization efforts. We have designed and implemented numerous innovative stormwater solutions in accordance with stringent NPDES permit requirements. Many of these alternative stormwater treatment and LID designs have included water quality treatment using infiltration basins/trenches, bioretention systems, rain gardens, constructed wetlands, landscape/soil stabilization measures, proprietary units, porous pavement features, and engineered treatment systems. The GES Team has also assisted with design and evaluation of non-structural controls including ordinances and by-laws, public outreach programs, and stormwater utilities.

Stormwater/Watershed Analysis & Modeling

The GES Team has conducted dozens of comprehensive stormwater evaluations and watershed assessments. These assessments have involved project-specific stormwater analysis and modeling including:

  • Runoff Volume Calculations
  • Sizing and Design of Stormwater Conveyance and Treatment Structures
  • Dry and Wet Weather Sampling
  • Hydrologic and Hydraulic Load Modeling
  • Pollutant Loading Assessments
  • Effluent Discharge Monitoring
  • Receiving Water Sampling
  • Stormwater Monitoring and Sampling
  • Assessment of physical watershed processes such as mass wasting, soil erosion, hydrology, and channel geomorphology
  • Development of effective planning documents that can be used by foresters to guide land management decisions
  • Analysis of hillslope and channel sensitivity to resource management
  • Evaluation of road/forest management impacts on sedimentation and hydrology
  • Channel stability and sediment transport evaluations
  • Integration of long-term land/resource management planning and fish/wildlife needs
  • Analysis of cumulative watershed effects
  • Assessment of point and non-point source pollution
  • Drainage litigation expert witness services


The GES Team will develop Storm Water Pollution Prevention Plans (SWPPP), as well as perform Inspections, Sampling, Monitoring, Training and Reporting, as needed per the NPDES permit. Our Stormwater Specialists provide value-added services designed to provide the most cost-effective stormwater compliance solutions. We are specialized experts with knowledge of local, State and Federal regulations. The GES Team will expedite your SWPPP faster and more cost-effective than any civil engineering firms, and our local, state and national knowledge assures accuracy of your plans. 

Regulatory Requirements & Permit Compliance

Grace Environmental Services has an exemplary record and extensive background working with state, federal, and local regulatory authorities across the State of California. Our experience includes reviewing and providing review of State Water Resources Control Board operating permits from draft stages of the permit process through completion. The GES Team has successfully coordinated design submittal and approval of facility upgrades with both the California Division of Drinking Water and the Regional Water Quality Control Board, as well as the California Coastal Commission.

 Examples of State and Federal agencies we work with include:

  • State Water Resources Control Board
  • Division of Drinking, including:
    • San Diego
    • Los Angeles
    • San Luis Obispo
    • Fresno
  • Multiple Regional Water Quality Control Boards, including:
    • Region 3 (Central Coast)
    • Region 4 (Los Angeles)
    • Region 5F (Central Valley
  • US Environmental Protection Agency
  • Department of Fish and Game
  • California Coastal Commission
  • Air Quality Control Districts
  • Various Governing Authorities specific to project locations
With offices in throughout Southern California and the Central Coast, our stormwater team members are always local to your California project. 


Contact Us

(805) 431-6253

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