Blake Anderson is the harbormaster at the Santa Cruz Harbor in California. As harbormaster he oversees all the operations of the harbor, harbor patrol staff, which includes search and rescue, law enforcement and public safety. He also oversees administration of about 1000 boat slips and day to day operations of the harbor. 6 years ago, Blake was faced with the challenge of rapidly mapping the constant shifting sand shoals in the harbor and turned his attention to BioBase as a potentially rapid mapping system
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.
We promote BioBase as an automated “easy-button” solution for creating aquatic maps, but unfortunately, mobile acoustic data collection is not something you can push a button and forget about and expect perfect results. Like using most other sophisticated instrumentation, users need to monitor that the instruments are performing as expected and sometimes make adjustments if they aren’t.
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.
One of the best features of BioBase EcoSound and its sister technology for anglers, C-MAP Genesis, is the ability to aggregate partial maps created over time into a complete map later. The recent blog post on Ten Mile Lake in Minnesota, USA, details a notable example of the power of aggregation. However, changing water levels over the course of time can impact the accuracy of aggregated maps if recorded water depths are not offset against a standard benchmark water elevation.
As an addendum to our blog series on rapid, portable applications we wanted to experiment with a “thru-hull” mount of the 83/200 khz Lowrance HDS transducer on a kayak for mapping storm water retention ponds in an urban area of Minnesota (City of Maple Grove). Electrician putty (sold as “Duct Seal”) available for a few dollars at the neighborhood hardware store worked as a perfect medium for this application. Follow the series of pictures and captions to see how this worked!
|Electrician putty or “Duct Seal” available at most hardware stores can be used for shoot “thru-hull’ applications on kayaks or canoes|
|Figure 2. A 83/200 Lowrance skimmer transducer secured to the hull of a polyethylene kayak by duct seal putty. Care should be taken to remove all air bubbles from the mold before pressing in the transducer|
|James Johnson from Freshwater Scientific Services LLC gets his Lowrance HDS-5 all set to log data.|
|Tracks showing a concentric circle approach toward mapping ponds smaller than 10 acres. This one is 3 acres located in an urban area of Minnesota near Minneapolis (Maple Grove). Data took 30-min to collect|