Stream Corridor Assessments

HDSS takes the guesswork out of mitigation planning.

Do you ever feel that waterway project decisions that are based on limited data might be missing important issues? Decisions based on traditional site-based stream assessments are relying on intensive reviews of short stream stretches while the majority of the stream remains unseen. HDSS Stream Corridor Assessments encompass 100% of a stream corridor with geo-referenced video and data. The result is a much better understanding of factors that are impacting a stream for better mitigation planning.  

Our Methodolgy

Trutta’s High Definition Stream Surveys produce comprehensive stream corridor assessments that rapidly identify areas in greatest need of restoration or conservation. By providing continuous 1-meter longitudinal resolution of stream corridor conditions, HDSS gives planners the documentation they need to make more informed decisions.

As shown in Figure 1, the HDSS framework consists of six fundamental elements:

Figure 1. Elements of the Stream Corridor Assessment framework evaluated using the high definition stream survey technique. Discreate features are located within the corridor and can affect the stream form and function, most often along the streambanks or streambed.

1) Streambed;
2) Right streambank;
3) Left streambank;
4) Right riparian area;
5) Left riparian area;
6) Discrete features (Point data).

The first 5 elements are Continuous Data.
Man-made items (pipes, road crossings) or other 
discrete features of environmental importance (large woody debris) are Point Data, and can occur anywhere in the corridor.
When combined, 
Continuous Data and Point Data define the location, extent and condition of issues within the stream corridor to aid in planning and effective management.
Additionally, each element can be used independently to identify and target specific management actions.

HDSS produces large volumes of detailed video and data that support Mitigation Prioritization, Integrated Planning, and Impact Assessments. The high-definition video of the stream corridor can be linked to a database of information that is easily mapped in GIS software.


HDSS links video, data, and maps in one system. The video footage of this pipe crossing a stream is more informative than a description of a dot on a map.
Poor stream bank conditions, an example of a Contiuous variable.
Tires in the water, an example of a Discrete Feature, or Point variable. Knowing the locations of trash relative to access points can help prioritize stream clean-up efforts.
A logjam, another example of a Discrete Feature. Logjams are typically found downstream of unstable bank areas.

HDSS provides planners and managers with a comprehensive approach to understanding existing conditions throughout an entire stream corridor. HDSS will produce more accurate impact assessments and result in more effective integrated watershed planning, predictive modeling, and mitigation planning and prioritization. HDSS is also ideal for fulfilling permitting and compliance requirements, such as replacing the traditional Streamwalk survey (i.e., Visual Stream Survey and Impairment Inventory) of the MS4 permitting process.