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Marc Leisenring

Hydropower Licensing and Compliance

2026-09-23T13:26:26-06:00April 15th, 2026|Tags: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |

To help clients achieve stringent water quality goals, Geosyntec provides rigorous assessment and modeling services to assess the sources and factors that affect the delivery of critical pollutants across watersheds. Through our comprehensive studies and analyses, we provide technically defensible tools and approaches that can be used in the development of Total Maximum Daily Load (TMDL) calculations and watershed protection plans. In addition, we frequently turn to Use Attainability Analyses to examine site-specific water quality criteria that affect attainability goals under natural, human-caused, and economic conditions. Our hydrodynamic and water-quality models integrate inputs from point and nonpoint sources to support our engineers and scientists as they study impacts on water quality in receiving water. These models allow us to understand the assimilative capacities of a given body of water, propose best management practices that can affect pollutant impacts, and predict the time required for a system to recover after being altered. Using watershed studies, water quality monitoring, and hydrological and hydrodynamic modeling, we also can assess compliance with local, state, and federal water quality standards. Using all this information, we are better able to evaluate the magnitude, frequency, and duration of impacts of a wide variety of pollutant sources. Our practitioners offer extensive experience with geographic information system applications for spatial analysis, planimetric and thematic mapping, and data representation. We employ watershed models including the Watershed Characterization System (WCS), Better Assessment Science Integrating Point and Nonpoint Sources (BASINS), and the Watershed Assessment Model (WAMView). We also employ the Water Quality Analysis Simulation Program (WASP), the Environmental Fluid Dynamics Code (EFDC), and the Stream Water Quality Model (QUAL2K) for hydrodynamic and water-quality models. Our practitioners are at the forefront of policy analyses, regulatory compliance, and technology applications that promote sustainable water resources management and ecosystem restoration. We have extensive experience helping local governments develop and negotiate long-term control plans for combined sewer overflows, National Pollutant Discharge Elimination System (NPDES) permits, and consent orders. We also comment on Clean Water Act issues at the state and national level, including the development of new recreational use criteria for water bodies across the county and for the U.S. Environmental Protection Agency's new framework for integrated planning for wastewater and stormwater.

Geosyntec Practitioners Contribute to Washington Stormwater Conference

2026-04-09T09:56:00-06:00February 25th, 2026|Tags: , , , , , |

Marc Leisenring, Amy Smith, Ariel Mosbrucker, Christian Nilsen, Adam Tycaster, and Tom Wanzek will speak and moderate at the Managing Stormwater in Washington Conference.

Geosyntec to Contribute to EWRI O&M Stormwater Conference

2026-03-15T10:24:44-06:00March 15th, 2024|Tags: , , , , , |

Geosyntec practitioners will present five presentations at the Environmental & Water Resources Institute (EWRI) of the American Society of Civil Engineering (ASCE) Operation & Maintenance (O&M) of Stormwater Systems Conference. The conference will take place April 7 through 10, 2024, at the AT&T Hotel and Conference Center at the University of Texas at Austin in Austin, Texas. We are also sponsoring the event at the silver level.

Geosyntec Discusses the Latest in Industrial Stormwater Treatment

2026-03-15T10:24:21-06:00June 13th, 2023|Tags: |

Geosyntec staff will present at the 2023 Managing Stormwater in Oregon conference in Salem, Oregon, on June 14, 2023. Geosyntec’s moderators and panelists include Marc Leisenring, PE (Portland), Joey Hickey, PE (Portland), Ariel Mosbrucker, PE (Portland), Jack Lisin (Portland), and Christian Nilsen, PE, PMP (Seattle).

Geosyntec Announces the Appointment of 23 New Senior Principals

2026-03-15T10:24:15-06:00April 10th, 2023|Tags: , , , , , , , , , , , , , , , , , , , , , , |

The Geosyntec Family of Companies is pleased to announce the promotion of 23 individuals to the position of Senior Principal. Each of these new Senior Principals has made significant contributions to delivering outstanding projects to first-class clients, developing strong relationships with those clients, building our practices, leveraging their own expertise and experience of their colleagues, recruiting outstanding staff, and working collaboratively with their co-workers.

Geosyntec to Make Significant Contribution to the 2022 Managing Stormwater in Washington Conference

2026-03-15T10:23:29-06:00March 16th, 2022|Tags: , , , , |

Geosyntec practitioners will attend and participate in two panels at the 2022 Managing Stormwater in Washington Conference hosted by the Northwest Environmental Business Council (NEBC). The event will be held at the Greater Tacoma Convention Center in Tacoma, Washington on March 16, 2022.

Geosyntec Practitioners Assess Stormwater BMPs for Agricultural Land for the Iowa Nutrient Research & Education Council

2026-03-15T10:23:04-06:00September 30th, 2021|Tags: , , , , |

Geosyntec’s Adrienne Nemura, PE (Ohio), Marc Leisenring, PE (Oregon), Rich Wildman, Ph.D. (Oregon), Beth Toot-Levy (Ohio), and Jo Lewis (Oregon) contributed to the project.

Geosyntec Staff Contribute to the 2019 Battelle Sediments Conference

2026-03-15T10:21:14-06:00January 29th, 2019|Tags: , , , , , , , , , , , , , , , , , , , , , , , |

Geosyntec professionals will make a substantial technical contribution at Battelle's Tenth International Conference on Remediation and Management of Contaminated Sediments at the Hilton New Orleans Riverside in Louisiana on February 11-14, 2019.

Geosyntec Project and Staff Received the Outstanding Stormwater Research Project Award from California Stormwater Quality Association

2026-03-15T10:21:09-06:00October 30th, 2018|Tags: , , , , , |

Geosyntec's project, International Stormwater Best Management Practices (BMP) Database, was honored by the California Stormwater Quality Association (CASQA) with the Outstanding Stormwater Research Project Award at CASQA's 14th Annual Conference in Riverside, California on October 16, 2018.

Geosyntec Participation at the 13th Annual CASQA Conference

2026-03-15T10:20:36-06:00October 16th, 2017|Tags: , , , , , , , , , , , , , , |

Geosyntec staff made a significant technical contribution to the 13th Annual California Stormwater Quality Association (CASQA) Conference entitled "CASQA in the Capital: Building Bridges for Water" at the Sacramento Convention Center on September 25-27, 2017.

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