Trutta’s High Definition Stream Surveys are ideally suited to support complex waterway projects
Dam removals involve complex engineering and management, but one simple fact will never change: accurate waterway data is critical to the success of these projects. Without accurate data, project objectives can be jeopardized in many ways:
– the ability to accurately predict and measure project impacts declines;
– prioritized restoration locations might be based more on guesswork than reality;
– project methodology may not be optimized; and,
– permit applications can get bogged down in review.
Despite the obvious need for better data, far too often data is limited to areas within a few hundred yards of a project site. While such data may meet technical requirements, it often does not provide enough information to improve project success.
Trutta’s High Definition Stream Survey (HDSS) assessments are designed to collect more waterway data much faster than traditional collection methods. The HDSS technique involves the uninterrupted collection of geo-referenced data over long stretches of waterway (click here to see a more in-depth description 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.
Better data gives project professionals a more holistic understanding of the waterway factors they need to consider in their projects. Better data can streamline the approval process and lead to more confident planning and implementation decisions. Thoroughly documenting everything in a stream corridor means that HDSS data from a single survey can be used for multiple permitting requirements: FERC re-licensing, COE permitting, MS4, and others. Simply put, HDSS will improve the ROI of your dam removal or stream restoration project.
Please check out this video and read to learn more about HDSS and see how it was used in an actual dam removal project.
HDSS in Action: Goodwin’s Mill Dam Removal Project
Goodwin’s Mill Dam was an obsolete, breached dam located on Big Canoe Creek in Alabama. It was also a fish barrier that the U.S. Fish and Wildlife Service wanted removed. One primary project objective was to measure the impacts of removal three years following removal. To meet this objective, Trutta conducted HDSS on three mile stretches both up and downstream from the dam site immediately before removal in 2013 and three years after removal in 2016. Some of the key parameters measured included sedimentation and bank erosion.
The value of HDSS is evident in the graphics shown in the following series of slides. But these slides represent only a small fraction of the entire data set collected during this and other standard surveys. In a single survey, HDSS produces a large volume of data that can provide answers to all kinds of questions concerning the health of a waterway.
Sample 1: Differences in sedimentation before and after the dam removal. Note the accumulation of sediment below the dam removal site three years later.
Sample 2: Comparison of right bank condition before and after the removal of Goodwin’s Mill Dam. The highlighted area shows increases to very poor bank condition that occurred in the 3 years between surveys.
HDSS also revealed the existence of upstream banks that were experiencing a high rate of erosion. Survey data enabled us to calculate the annual sediment load these banks were contributing to the stream. The U.S. Fish and Wildlife Service took this information into account when they analyzed the sedimentation impact of the dam removal. This is important because a limited stream survey conducted at the immediate removal site would probably not have discovered this erosion. Without this information, conclusions regarding the sedimentation impact of the dam removal could have been inaccurate.
HDSS: A Better Data Solution
HDSS provides project professionals with more data, more quickly which results in lower costs.
HDSS gives planners the information they need to make more confident planning decisions.
Further Reading: Dam Trends in the U.S.
Read on for more information about dam removal trends in the U.S. today.
There are millions of small dams located throughout the U.S.
The EPA has inventoried approximately 87,000 large dams and estimates between 2,000,000 to 2,500,000 small and medium sized dams in the U.S. Small dams include those used for fishing ponds, amenity lakes, farm ponds, and old mill dams.
Dam removals are often necessary to improve river conditions
EPA data indicates a growing awareness of the need to address obsolete dams that impair our waterways. Many small dams have long since lost their original beneficial use or purpose and are becoming structurally unsound. The percentage of dams that no longer serve a functional purpose ranges from 75% to as high as 90%. These obsolete dams, regardless of size, are impacting the ecological quality of the river or stream where they are located.
Small dam removals are on the rise for numerous reasons:
– ecological restoration;
– economic development of communities;
– addressing concerns with localized flooding;
– improvement of recreational opportunities;
– restoration of fish spawning and migration;
– addressing safety issues for recreational users due to dangerous hydraulics below dams;
– response to storm events and ensuring the safety of downstream communities;
– ongoing costs and liability for needed dam repairs, maintenance, or required upgrades to meet new safety or environmental standards.
Contact us today to discuss how we can help with your waterway project!
Dam Removal Monitoring: Big Canoe Creek, Alabama