Understanding the environmental effects of a proposed project can be a costly, complicated, and time-consuming task, but using HDSS solves these problems. HDSS surveys cover a continuous broad spatial extent (often > 50 rkm) with a consistent near 1m documentation of the physical and biological habitat components along the stream corridor. A single survey can easily provide the information necessary to evaluate the effects of the proposed project and alternatives. While repeated surveys are an excellent tool for monitoring before and after studies.

By applying the HDSS approach, you benefit by:

  • Quickly and accurately determine the extent and distribution of conditions within your system.
  • Seeing results quickly with continuous (better) data over a larger area (more).
  • Answering multiple management questions from a single survey.
  • Quickly prioritizing your management needs.

HDSS data provide environmental data required during:

    • Municipal Separate Stormwater Sewer System (MS4)
    • Illicit discharge – IDDE
  • FERC licensing,
  • Threatened and Endangered (T&E) species,
  • Submerged Aquatic Vegetation permits,
  • Total Maximum Daily Load (TMDL)

The HDSS approach provides a powerful solution to these problems.


A High Definition Stream Survey (HDSS) is a complete system to rapidly document stream and outfall conditions. It will provide information necessary to more effectively manage the stormwater component of cleaner water. You will understand the context, distribution and severity of the problems in your streams and effectively develop long-term plans to solve those problems.

Under the National Pollutant Discharge Elimination Standards (NPDES), Municipal Separate Storm Sewer Systems (MS4) require specific data to complete the permitting process. The high definition stream survey technique (HDSS) provides this critical data and more accurately represents conditions within the stream corridor when compared to traditional methods. This is possible because HDSS is the only method that provides continuous, reviewable data over the entire corridor.

The HDSS Stream Corridor Assessment provides managers a comprehensive view of the riparian, streambank and streambed condition as well as all infrastructure (i.e. outfalls) within the stream corridor. These data can be used for Rehabilitation Scoring, which allows stormwater managers to compare the relative cost/benefit of different Best Management Practices. Managers can then successfully prioritize restoration efforts within a given range of budget and resource constraints.


Documenting Illicit discharge and Potential Locations

High Definition Stream Survey (HDSS) technology can be a useful tool in the Illicit Discharge Detection and Elimination (IDDE) process by providing detailed data on the type, severity, and location of continuous illicit discharge locations. Additionally, HDSS data provides the location and relative size of all outfalls, which can be reviewed as potential intermittent and transitory discharge locations. By using HDSS data to identify and locate the sources and potential sources of illicit discharges, you can more effectively plan to eliminate illicit discharges and improve water quality.

IDDE refers to the process of identifying, investigating, and eliminating the unauthorized discharges of pollutants into surface waters, such as rivers or streams. The goal of IDDE is to prevent the discharge of pollutants into stormwater systems, which can contaminate surface water bodies and negatively impact water quality. These discharges can come from a variety of sources, including industrial facilities, stormwater systems, and sewage systems. They can be continuous, occurring on a constant basis, or intermittent, occurring only occasionally.

By utilizing the HDSS approach, you benefit by:

  • Quickly and accurately determine continuous illicit discharge locations
  • Quickly prioritize your management actions based on illicit discharge severity
  • Easily review High definition video of each outfall to address additional needs or confirmation


Threatened and Endangered (T&E) species are species that are at risk of extinction due to various factors such as habitat loss, over-exploitation, disease, and climate change. Aquatic species, including fish, amphibians, and mollusks, are particularly vulnerable to habitat destruction and other threats, as they are often highly dependent on specific types of aquatic environments for survival.

HDSS is a tool that is used to collect detailed data on aquatic habitats and the species that live within them. HDSS data provides consistent, high-resolution documentation of various habitat components, such as depth, substrate, cover, velocity, and water quality, which can be used to create habitat suitability models. These models can help scientists and resource managers understand the habitat requirements of different species and predict the distribution of the species within a given area.

Environmental regulations, such as the National Environmental Policy Act (NEPA), include conducting impact assessments to evaluate the potential effects of a proposed action on T&E species and their habitats and developing mitigation measures to minimize or avoid negative impacts. To create defensible impact assessments, managers and scientists often rely on advanced technologies and techniques, such as our High Definition Stream Survey (HDSS) technology, to better understand and protect these species.

One of the key benefits of HDSS data is its ability to cover a broad spatial extent, often over 50 river kilometers or more. This allows scientists to assess habitat conditions and species distribution over a large area, providing a more complete understanding of the ecosystem and the factors that influence the distribution of species within it.

The rare and elusive nature of many threatened and endangered species can make it difficult to study and understand their life histories and critical habitats, which is essential for effective conservation and management efforts. By integrating HDSS data into habitat suitability models, resource managers and conservationists can more effectively target conservation efforts and identify areas that are most important for T&E species. This can help ensure that limited resources are used effectively to protect these species and their habitats.

By applying the HDSS approach, you benefit by:

  • Quickly and accurately determining the amount and distribution of critical habitat.
  • Identify areas that may still hold T&E Species for further surveys.
  • Identify areas that would provide suitable habitat with appropriate restoration efforts.
  • Cover large areas to provide highly credible support for permit applications.
  • Habitat data from a single HDSS survey can be used for multiple species and/or life stages.
  • Species-specific habitat use criteria can be based on published data or using your species survey data.



The long and complex FERC licensing process is likely to vary based on the needs and sensitivity of the project area’s resources. During the environmental review phase, FERC conducts a thorough review of the potential environmental impacts of the proposed project on wildlife and water quality.

HDSS is a fast and cost-effective method to complete the environmental studies required during the Environmental review phase of the FERC licensing process. Most projects are to be completed within four months allowing you to quickly determine the environmental effects and assess alternatives to minimize environmental impacts. HDSS allows you to conduct a single survey that can be classified and reclassified enabling you to address multiple environmental issues from a single survey. When appropriate HDSS data can also be used to develop models to assess the cumulative effects and help address the information needs during the NEPA process. Additionally, the HDSS survey is not a subsample, so no data extrapolation is required, reducing the potential for error and/or bias.

A single HDSS survey provides data required to describe current conditions and potential impacts, develop mitigation measures, and assess impacts on threatened and endangered species, fishing, and boating. This would allow you to maximize the developmental benefits of your proposed project.

By applying the HDSS approach, you benefit by:

  • Understanding the physical and biological conditional along your stream.
  • Quickly and accurately address the needs of multiple studies with a single survey.
  • Quickly and accurately assess data at the appropriate spatial scales to address the necessary questions above.
  • Quickly develop alternatives based on unique characteristics along the river or stream.
  • Easily review the HDSS StreamView video for additional data needs.
  • Easily integrate species data or additional habitat assessment for a more complete understanding.


Total maximum daily loads (TMDL) is a written, quantitative assessment of water quality problems and contributing sources of pollution at a system scale. TMDLs can easily be understood as a pollution “budget” for the system. HDSS will aid in meeting the applicable water quality standards by clearly identifying the links between the type of impairment, the causes of impairment, and the pollutant load reductions needed. This is accomplished with a continuous survey along your stream corridor. This will allow for the development TMDLs and viable mitigation for impaired waters or secure protection of threatened waters.

The HDSS provides the data necessary to develop, implement, and monitor your TMDL plan. This data can be easily assessed to prioritize your planning strategy to ensure the success of one pollutant reduction strategy over another. With a complete understanding of the types, ranges, and distribution of pollution sources in your stream corridor, the implementation of your management strategy can be done with confidence. Additionally, monitoring studies (e.g., before and after) are supported with HDSS data.

By applying the HDSS approach, you benefit by:

  • Quickly and accurately obtain baseline data for the development of TMDL standards or monitoring data to assess mitigation efforts.
  • Quickly and accurately identify locations within your survey area contributing to elevated levels.
  • Quickly and accurately identify locations of increased turbidity, temperature, dissolved oxygen, and pH.
  • Easily integrating water quality grab samples into HDSS survey.
  • Easily review the high-definition StreamView video of the entire survey area for future reference.


Dam Removal and Stream Restoration Projects​

Are you certain that your Nationwide Permit 53 or 27 applications adequately address the potential impact to aquatic life? If your waterway data is insufficient to support your assumptions, your permitting process could be prolonged and more costly than it needs to be. A High Definition Stream Survey (HDSS) provides a complete assessment of a stream corridor, including detailed data about T&E species and sensitive habitat. Give yourself the benefit of more confident planning and implementation decisions by ensuring you have the data you need to get your project approved.

The HDSS technique involves the uninterrupted collection of geo-referenced data over long stretches of waterway (click here to learn more about HDSS). The data can be collected on floatable and non-floatable waterways using an array of video equipment and other sensory equipment that convert blue lines on a map to data-rich GIS layers backed up by video documentation. Aquatic habitat can be thoroughly mapped to show sensitive areas that must be considered in the project. HDSS processing will compile the data and produce deliverables tailored to optimize your permitting requirements.

Don’t limit your data to within a few hundred yards of a project site. HDSS results can easily provide an understanding of your project miles up- and downstream of a dam removal or other stream restoration project ensuring that you will successfully show the improvements from your project.