The waters of Western Port in southeastern Australia are a recreational fishing haven and hidden beneath its turbid waters, a unique fragile seafloor community has been newly described. Here, bryozoans, skeleton-forming filter-feeding organisms also known as ‘lace corals’, form expansive areas of reef that support a high diversity and abundance of macroinvertebrates important to snapper and other prized recreational fish species.
We are grateful to the aquatic research community who continue to verify and validate Consumer Sonar Technologies (Lowrance) and BioBase automated mapping platform to produce scientifically valid outputs that benefit aquatic conservation. We are excited to see the recent publication of research out of the University of New Brunswick that evaluated the accuracy and precision of Lowrance and BioBase’s EcoSound depth and vegetation outputs. The research is published in the open access journal Diversity and can be downloaded here. Below is the abstract
The development of consumer hydroacoustic systems continues to advance, enabling the use of low-cost methods for professional mapping purposes. Information describing habitat characteristics produced with a combination of low-cost commercial echosounder (Lowrance HDS) and a cloud-based automated data processing tool (BioBase EcoSound) was tested. The combination frequently underestimated water depth, with a mean absolute error of 0.17 ± 0.13 m (avg ± 1SD). The average EcoSound bottom hardness value was high (0.37–0.5) for all the substrate types found in the study area and could not be used to differentiate between the substrate size classes that varied from silt to bedrock. Overall, the bottom hardness value is not informative in an alluvial river bed setting where the majority of the substrate is composed of hard sands, gravels, and stones. EcoSound separated vegetation presence/absence with 85–100% accuracy and assigned vegetation height (EcoSound biovolume) correctly in 55% of instances but often overestimated it in other instances. It was most accurate when the vegetation canopy was ≤25% or >75% of the water column. Overall, as a low-cost, easy-to-use application EcoSound offers rapid data collection and allows users with no specialized skill requirements to make more detailed bathymetry and vegetation maps than those typically available for many rivers, lakes, and estuaries.
River channel thalwegs (the line of lowest elevation within a valley or watercourse) are often dynamic, and sometimes hidden features of large river systems. Especially low slope or impounded systems. The thalweg is a critical geomorphological feature of river and reservoir systems and affects everything from sediment transport, to fisheries habitat, to algae or invasive plant control.
Thus a good bathymetric contour map is a necessary pre-requisite for effective river and reservoir management. Here, we walk you through how to use new real time technologies (C-MAP’s Genesis Live) to produce smooth, precise, and accurate maps of hidden river thalwegs all within one trip to the site and with automated post-processing with BioBase’s EcoSound. We’ll use an annotated image gallery to take you through this process.
Another FAQ we get is wondering if there are published studies using BioBase technology? There are many legacy applications on which the BioBase technology is based. Further, now that a sufficient passage of years has accumulated to support the “research to publication” cycle, we’re happy to share several BioBase-specific studies published in the peer-reviewed literature. This is far from an exhaustive list and we’ve intentionally left out the niche growth in consumer side-scan technology for creating habitat maps. If there are good published papers you know of that are not on this list, please share in the comments.
Lake Yankton, a 332-acre backwater lake on the Nebraska/South Dakota border had a problem. In the summer of 2011, the Missouri River flooded, spilling into the lake a number of undesirable invasive rough fish, including large numbers of carp (silver, bighead, grass, and common), smallmouth buffalo, and gizzard shad. Notorious for stirring up lake bottoms while feeding and spawning — and for overeating zooplankton and aquatic plants — these species degrade water quality and fisheries. Overrun by these invasive species, Lake Yankton soon looked like chocolate milk, with a water clarity of only three inches — that’s right, inches, not feet. So the cavalry was called in to assess the situation and provide a solution. Leading the effort was Nebraska Game and Parks Commission District Fisheries Manager Jeff Schuckman. Fortunately for Nebraska anglers, this wasn’t Schuckman’s first rodeo. He knew the lake could be rehabilitated with careful application of Rotenone, a common fish-killing chemical. The challenge would be to determine just how much of the chemical was needed, and then purchase and apply just enough to do the job — no more, no less.
Maybe you’ve been hearing about this term in sonar circles called “Chirp” and noticing that most consumer sonar units now come with Chirp capability. Indeed, Chirp is a game changer for more precise definition of acoustic targets suspended from bottom (e.g., fish) and the technology is helping more anglers find fish in a wide range of aquatic environments (Figure 1). But what does Chirp mean for mapping the bottom of waterbodies? Does it provide any advantages or disadvantages over traditional 200 kHz frequency broadband sonar that is the foundation of Insight Genesis and BioBase
EcoSound mapping services? Here we take a brief look at Chirp, explain what it is, and present some findings from preliminary tests in a couple of different lake environments.
Earlier this year, Senior Biologist Scott Bryan from the Central Arizona Project (CAP) blogged about how the CAP is using BioBase to manage sedimentation in Arizona’s lifeblood 336-mile aqueduct. Since then, CAP GIS Wizard Glenn Emanuel has worked some amazing magic on the BioBase grid exports using Spatial and 3D Analyst Extensions for ArcGIS (Figure 1).
Figure 1. Images showing the change in sediment volume prior to and after experimental dredging activities in a Forebay of the CAP canal. The Raster Calculator in ArcGIS’s Spatial Analyst was used to subtract a “current” bathymetry from a baseline bathymetry (e.g., “as built”) to estimate sediment height and volume. Images are 3-dimensionally enhanced using 3D Analyst for ArcGIS. Image courtesy of Scott Bryan and Glenn Emanuel, Central Arizona Project
The data and images allow CAP to make informed decisions regarding the efficiency of sediment removal operations. In addition, ArcScene was used to produce a 3D scene of the forebay (Figure 2), which can then be animated with a video fly-through.
Figure 2. “Fly-through” images of sediment height in Little Harquahala Forebay in the CAP Canal collected by Lowrance HDS sonar and GPS, BioBase cloud processing software, and finally exported/imported into ArcScene. Image courtesy of Scott Bryan and Glenn Emanuel, Central Arizona Project.
Any user of BioBase properly equipped with the proper third party GIS software can create these amazing map products that are more than just pretty pictures. They create a real-life, tangible perspective of aquatic resource conditions that BioBase users are interested in managing, protecting, and restoring.
We love to show off the accuracy of our submerged vegetation mapping algorithm. Check out this break in the weeds that was picked up and clearly displayed in the ciBioBase vegetation layer:
The BioBase vegetation layer is automatically generated by powerful cloud computers so you receive an objective output every time. The white line on the right and red dot on the left show the boat position as a cross section and aerial view of the water column respectively.
Submerged vegetation is displayed as percent biovolume (BV%) which represents the percent of the water column occupied by plants. This provides a clear picture of total plant abundance from each trip on the water. Data can be passively logged because none of our users have to do any of the processing when they get back to the office. Do what you were already planning to do and our automated system will take care of the rest.
Let us know if you have any questions about how this process works!
The Central Arizona Project (CAP) is a multipurpose water resource development and management project that provides irrigation, municipal and industrial water to much of Arizona. The primary means of water conveyance is a 336-mile concrete-lined aqueduct that transports water from the Colorado River, on Arizona’s western border, across the State to Phoenix, and then southward to the aqueduct terminus near Tucson. Each year, over 1.5 million acre-feet of water is delivered to our customers.
Since its completion in 1993, the aqueduct system has experienced increasingly severe sedimentation that creates problems within the pumping plants and in the aqueduct itself. Because the sediments can decrease the flow capacity of the aqueduct, cause damage to pumps and internal systems, and restrict flow through critical filtration units, it is imperative that dredging operations occur periodically.
CAP forebay dredging in 2009
In the past, CAP performed intensive sonar based sediment studies to determine bathymetry and the amount of deposition in the forebay of each of the 13 pumping plants. The surveys show when and where dredging operations should occur. These surveys were contracted to outside companies with costs ranging from $40,000 to $120,000 annually.
In 2012, CAP began to use the sonar technology provided by BioBase to conduct its own bathymetry surveys in the pumping plant forebays. Water depths are compared to historical baseline surveys and the volume of sediment in each forebay can easily be calculated. Annual surveys allow us to compare sedimentation from year-to-year to determine loading rates and critical areas to target sediment removal. Surveys of all 13 forebays can now be accomplished in three days rather than six months, and when compared to the expensive surveys from the past, are equally as accurate.
Blue-scale bathymetric map of a CAP forebay. The light blue contours show an area that is extremely shallow and is in need of sediment removal.
Example transect design and resultant bathymetric map coupled with the sonar log viewer. Notice the detailed image of the forebay’s trash racks produced by Lowrance HDS DownScan
This new approach to bathymetric and sedimentation mapping saves time and money, allows us to evaluate results immediately, and makes dredging operations more efficient and timely.
Scott Bryan is the Senior Biologist for Central Arizona Project (CAP). After receiving an M.S. in Fisheries Management at South Dakota State University, Scott worked as a research biologist for Arizona Game and Fish for 10 years, then specialized in lake and stream management for seven years at a private consulting firm in Albuquerque. Scott’s current position at CAP includes a broad scope of work, including aquatic and terrestrial vegetation control, fisheries and wildlife management, invasive species research, and water quality monitoring.