Training EcoSat Vegetation Classifications: User tips

What is EcoSat?
EcoSat delivers a one-of-it’s-kind semi-automated cloud processing of very high resolution satellite imagery to map nearshore vegetation and coastal benthic habitats.  EcoSat uses the latest multi-spectral imagery from reputable providers such as Digital Globe (World View 2,3 and 4), Airbus Defence and Space (Pleiades), and ESA’s Sentinel program and industry standard image processing techniques.  Sophisticated Amazon Web Service cloud infrastructure rapidly processes imagery, creates reports and imagery tiles, and delivers detailed habitat maps to user’s BioBase dashboard where it can be analyzed and shared.  Average turnaround time from imagery tasking order to delivery of results is 90 days.  The rapid and standard processing methods are allowing entities like the Florida Fish and Wildlife Conservation Commission to establish regular monitoring programs for emergent vegetation.  The extremely long and expensive one-off nature of conventional remote sensing mapping projects using non-repeatable tailored techniques has prevented natural resource entities from assessing the degree that habitats are changing as a result of environmental stressors such as invasive species invasions and climate change.

Continue reading “Training EcoSat Vegetation Classifications: User tips”

Portability Options for Your Lowrance

We recently sent out a mailer to our subscribers letting them know about the portability solutions that we have come up with.  Within minutes we received photos and details from many of our customers about how some they have used a little ingenuity to mount their Lowrance units on unique water craft.  Below we have a photo gallery of images that could help you design your own portable setup.  Of primary importance, however, is a mount that minimizes cavitation (air bubbles) directly under the transducer (e.g., surface noise) and maintaining a correct angle on the transducer.  See recent blogs on this topic. The preferable solution is to permanently mount separate transducers following DIY guidance like shown here on each survey craft and just move the Lowrance Elite or HDS display from boat to boat.  But if the job calls for a fully portable mount, we can help!

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BioBase Helps Manage Honeoye Lake Macrophyte Harvesting Program

Guest Blog By Terry R. Gronwall, Chairman of the Honeoye Lake Watershed Task Force (Honeoye, NY)
Honeoye Lake is one of the smaller (~1,800 acres) Finger Lakes in Upstate New York.  We have been managing our macrophyte population by using a harvester for about 25 years.  The objective of our harvesting program is to both provide relief for the recreational lake users and to remove biomass containing phosphorus from the lake every summer.  We average around 800 wet tons of biomass removed per season.

When we learned about ciBiobase we saw this service as a way to make our macrophyte harvesting operation more efficient by concentrating our efforts on areas in the lake that have macrophytes growing through most of the water column.  This is shown as the red zone on our macrophyte maps.  We plan to monitor our actual harvesting rates relative to our macrophyte maps over the summer harvesting season to see if we achieve our goal of increased productivity.

Continue reading “BioBase Helps Manage Honeoye Lake Macrophyte Harvesting Program”

CHIRP from a bottom mapping perspective

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.

Figure 1. Sample sonar screen grab from a Lowrance HDS Gen3 running high Chirp frequencies over numerous fish targets.

Compressed High Intensity Radar Pulse
Acoustic target separation is often tied to the pulse length or duration.  Longer pulses give better depth penetration, but less target separation.  For suspended targets, Chirp represents the best of both worlds by sweeping many short pulses of a range of frequencies within a relative long pulse burst.  Three Chirp ranges (Low 40-60 kHz; Medium 85-145 kHz; and High 130-210 kHz) typically accommodate most situations for locating fish targets throughout a range of depths.

Chirp Performance For Tracking Bottom in a Range of Conditions
It has been well established in recreational marine circles that Chirp is a benefit to mapping suspended targets, however differences in how bottom is declared with Chirp vs the traditional single 200 khz frequency (for which BioBase EcoSound and Insight Genesis was developed) is a question for which we recently sought an answer.

Tracking Bottom in Dense Submersed Aquatic Vegetation
Tests were conducted in Gray’s Bay of Lake Minnetonka in August 2014.  Repeated transects were run over a dense bed of submersed vegetation with a Lowrance Elite 7 Chirp, and HDS Gen2 with a Chirp compatible SonarHub running both traditional 200 kHz and High Chirp frequencies.  Below is a plot showing the EcoSound depths from both the 200 kHz and High Chirp Frequencies (Figure 2).

Depth was significantly greater and was closer to truth based on sonar log verification with the traditional 200 kHz frequency than High Chirp.  However, the actual difference in depth declarations between the frequencies was only 6 inches on average.  Plant canopies apparently more quickly extinguish the Chirp signal than the 200 kHz.  Based on these findings and other tests, the 200 kHz frequency remains the recommended frequency for mapping aquatic plant dominated bottoms.

Figure 2.  Average depth declaration by BioBase over repeated transects in dense submersed vegetation (avg plant height of 3 ft) running both Chirp and 200 kHz frequencies.

Bottom Declarations Over Soft Bottoms
Frequently, we get questions regarding whether EcoSound can determine the depth of sediment.  The answer is yes, but only if the “true” bottom is known (e.g., “as built” bathymetry in a human-engineered system) or a desired bottom can be modeled (e.g. how deep does it need to be for waterway management objectives).  If a true bottom can be described, then Lowrance and EcoSound should tell you the precise depth where the water meets sediment.  Simple subtraction of map layers in ArcGIS with Spatial or 3D Analyst (Raster Calculator) will produce detailed sediment maps like produced by the Central Arizona Project.  A question that piqued our interests however, was the difference between 200 kHz and Chirp bottom declarations in relatively soft bottoms.  Because the Chirp signal appears to attenuate more quickly than 200 kHz, could Chirp be a solution for more precisely mapping the depth of the sediment water interface in softer, plant free bottoms?

The St. Johns River Water Management District at Lake Apopka FL helped address this question by sharing Chirp and 200 kHz frequency sonar logs over bare soft bottoms on Lakes Apopka and Griffen in Florida, USA.  Analysis of approximately 100 data points across both frequencies found almost no differences overall and deviated only one to three inches from true bottom determined from the sonar log (Figure 3).

Although the vast majority of user sonar logs have bottoms that are clearly defined visually and acoustically, there are some bottoms that are so soft and unconsolidated that they are source of philosophical discussions of where the “bottom” actually is.  Further research and testing is needed to determine whether Chirp can be a unique solution for better depth tracking in these and other special use cases where bottoms are highly flocculent.  The more rapid attenuation of the Chirp signal than the 200 kHz frequency in plant bottoms (which may present a similar acoustic signature to a soft bottom) suggests it could be a solution in a narrow range of use cases where the 200 kHz channel penetrates too far into the bottom.

Figure 3. Bottom depth declarations (solid line) with Chirp (Top) and 200 kHz (Bottom) over a soft bottom on Lake Apopka, Florida USA.  Although in this case, Chirp produced a slightly shallower depth (8.0 ft) than 200 kHz (8.7 ft), overall we found very small differences between frequencies in depths over moderately soft, plant-free bottoms.

Conclusion: Use 200 kHz for Mapping
EcoSound and Insight Genesis mapping algorithms were developed and optimized for the 200 kHz frequency.  Over plant-free bottoms, both 200 kHz and High Chirp should perform similarly and precisely map the sediment-open water interface.  However, in bottoms dominated by submerged vegetation, the 200 kHz frequency will produce the best depth declarations and clearest delineation of the vegetation-sediment interface.

Transect Design: Consideration of Scale

One of the most frequently asked questions by BioBase EcoSound users is, “how far apart should I space my transects for creating maps?”  Although as always, the most appropriate response is: “it depends,” we still offer solutions below that cover the most common use case scenarios.  We thank our partners at NC State University Department of Crop Science for contributing useful data from Waccamaw Lake in North Carolina USA.

Full Bay/Lake Map on a Large Lake

Transects can be designed in ArcMap using the Fishnet Tool in the ArcToolbox (see BioBase Support & Resources).  In this case, 200 m transects perpendicular to the longest shore with one nearshore loop was created.  The total length of transects in this instance equaled 189 km (117 mi) and would take 23 field hrs to map driving 8 km/h (5 mph).  ESRI Shapefiles or Google Earth .kml path files can be converted to .gpx for your Lowrance Chartplotter.  Convert the Trail to a Route and let out Outboard Autopilot do the mapping for you!
Aquatic Vegetation biovolume from raw sonar data from a Lowrance HDS, processed by BioBase, and imported and converted to raster with ArcMap.  In BioBase, the map buffer around each side of 200 m transects were increased to 100 m which produced a complete map and increased the resolution of each local prediction (i.e., a grid cell) from 5-m x 5-m (default) to 25-m x 25-m.  In this case, a coarse-resolution full lake map was the objective for more precise targeting of follow up surveys.

Follow up, intensive surveys in areas of interest

Zoomed in area near boat launch where an invasive aquatic plant species was located during initial BioBase mapping surveys.  Follow-up intensive surveys were carried out to more precisely map infestations.
Coarse-resolution aquatic vegetation BioBase biovolume map created from 200-m transects (left) and detailed biovolume map created from follow up intensive BioBase surveys (right).  Overall vegetation statistics are generated for this NW area of Waccamaw.  Note only subtle differences in the overall numbers, but great difference in the precision and detail between maps collected at different survey intensities.  Scale of inference and tradeoffs of alternative approaches should be considered when designing surveys and implementing management actions

Mapping small bays and fingers? Try concentric circles

For mapping small bays, inlets, fingers, canals, try a concentric circle approach to mapping.  Create a new trail on your Lowrance chartplotter and start logging data while traveling as close to shore as navigable.  Methodically work your way inward as you encounter your previous trail while avoiding overlap.  When you get to the middle, stop recording, you have a complete map! 

Situational awareness – mapping vegetation edges

Use a perpendicular to shore approach if you are interested in mapping the edge of aquatic plant growth in a deep lake.  Or if using a concentric circle design, ensure that you travel in a weave-like fashion over the bed edge.

Situational awareness – creating the smoothest bathymetry map

Get the smoothest bathymetry with a concentric circle transect design

Situational awareness – dealing with extremely steep slopes

Traveling along very extreme slopes can present mapping challenges because how rapidly depths change and because the acoustic beam intercepts the bottom at an angle. Indirect sonar returns increase the likelihood of erroneous bottom typing.  In these cases, the best bathymetry is achieved by avoiding the slope and mapping along the top and bottom of the shelf.

Situational awareness – mapping small patches


Patch of hard bottom (brick red on map) in an otherwise soft-bottom lake (light tan).  Surveyor noticed double echo on sonar chart while mapping and diverted course to methodically cover hard patch and thus more precisely map its extent.  

We hope this gallery of images and explanations can help BioBase users make the most efficient use of their time on the water mapping and produce the best possible aquatic habitat map!  For more information search this blog, aquatic resource mapping user forum, or contact us at info.biobase@navico.com.

New Polygon and UPI Treatment Tools

One of the most popular features of BioBase is the polygon tool that allows users the ability to trace out areas of their maps for detailed calculations of mapped attributes (e.g., area, depth, water volume, aquatic vegetation statistics).  Until now, users could not use the same polygon on multiple trips.  That has changed and now any polygon a user creates in any trip will be available in all trips to that waterbody!  Now, users can monitor change to aquatic habitat within specific areas of interest (Figure 1).  Further, users can upload and overlay waypoints within polygons, and thus inform the composition of the polygon area (e.g., aquatic plants, substrate composition, muck depths, reefs, etc.)

Figure 1. Comparison of changes to aquatic vegetation in 2013 and 2014 within the same delineated polygon area of a lake in Minnesota.  Waypoints showing the presence of the native aquatic plant, coontail was also uploaded and overlain simultaneously to demonstrate how species information can be combined with the vegetation biovolume map to better understand aquatic plant bed composition

BioBase teams up with UPI to deliver precision herbicide treatments
Since its launch in 2011, BioBase has taken the guesswork out of aquatic plant bed mapping and delineation.  Now with a partnership with United Phosphorus Inc, we’ve developed a treatment recommendation tool that automates the estimation of UPI herbicide based on the user-delineated polygon area, target species, desired product and application rate (Figure 2).  Whole Lake treatment recommendations can be created if >20% of the lake area is mapped.  Users control the accuracy and precision of treatment recommendations by their mapping coverage.  A whole-lake prescription will be more accurate and precise if 100% of a lake is mapped with 40-m transects than 20% of a lake with 100-m transects.  Optimal mapping coverage in different aquatic plant environment is an area of research that we are hopeful will grow!

Figure 2. After a polygon is created, authorized users can click on the UPI Treatment Tool button and generate an herbicide recommendation based on one or more polygon areas or the entire lake.
Figure 3. After a treatment is saved, a treatment history is created.  Click on the “view report” for report for the last sample treatment (see example).
Embed Treatment Reports in Final Reports or Forward to Permitting Officials
Applicators and lake managers can also quickly produce automated vegetation summary and treatment reports (Figure 4).  These static html reports are stored a remote file server and can easily be shared with lakeshore owner customers, partners, or government regulators.  No account information outside of the trip owner is disclosed or accessible by recipients.  These reports demonstrate the objective and transparent nature of BioBase and UPI tools, thus minimizing uncertainties (and controversy??) by all interests involved in projects.
Figure 4. Example automated UPI treatment report generated with any UPI treatment recommendation.  Hyperlink of html report can be embedded in any electronic report or email 
By using objective, quantitative tools delivered by BioBase and the UPI Treatment Tool, the precise amount of herbicide can be delivered to infestations and thus control costs, maximize effectiveness, limit non-target impacts, and ensure regulatory compliance.  If you are interested in using the UPI Treatment Tool (both current and interested future BioBase subscribers), please contact your regional UPI Sales Rep.

For detailed instructions on how to use the Polygon Tool consult the Operators Guide in Support & Resources in your BioBase Account or see our YouTube Demonstration Video

Citizen Lake Mapping: Power of Aggregation!

Ten Mile Lake in Hackensack, Minnesota is one of many crown jewel lakes of Minnesota.  It’s no wonder the Ten Mile Lake Association is serious about lake monitoring and conservation.  When BioBase approached TMLA member and hobby Fisheries Biologist Dr. Bruce Carlson in late 2012 demonstrating how members could passively log their sonar data and map habitat while enjoying a pleasure cruise or fishing, Dr. Carlson jumped at the opportunity.

Two hundred and twenty four trips spanning two seasons (2013-2014) and 5,065 acres (2,049 ha) later, Dr. Carlson and colleagues have produced the most accurate and detailed map of Ten Mile Lake on the planet (Figure 1)!

Figure 1. Track lines from 224 Lowrance sonar logs uploaded to BioBase and merged (left) and resultant contour map (right) produced automatically for Ten Mile Lake, Hackensack, MN USA.  Ten Mile Lake is a 208-ft (63-m) deep lake with 16-ft (5-m) clarity.

When comparing the hand-made maps of 1947 from the long-dissolved MN Dept of Conservation one has to wonder if creating this map took a dedicated and highly trained survey crew all summer to create this map (Figures 2-4)?  Now a critical mass of anglers or pleasure boaters with no mapping experience can create a community-sourced contour map that rivals anything produced by the most trained hydrologists using the most expensive “survey-grade” echosounders.

Figure 2. Original map of Ten Mile Lake created in 1947 by the MN Department of Conservation (left) next to the aggregated map produced by TMLA volunteers in 2014 after uploading to BioBase.  Maps created in the mid 20th Century remain the only maps offered to anglers and recreationists by a large number State Natural Resource agencies. Often these old maps are digitized and artfully recontoured and shaded for resale.
Figure 3. Close up of the 10-ft contours displayed in the 1947 Department of Conservation map compared with the 2014 aggregated map created by TMLA volunteer uploads to BioBase.
Figure 4. Tight zoom of 10-ft contours from 1947 MN Department of Conservation map (ink blob on top) compared with 3-ft contours from aggregated map created by TMLA volunteer uploads to BioBase.

Not just an improvement in aesthetics!
The efforts of TMLA and volunteers from other Lake Associations across the US (e.g., Lake Paradise, Honeoye, Prior Lake) are producing not only pretty maps but also updated digital maps for the public and highly detailed fish habitat and aquatic plant data for aquatic researchers and managers.

First, public trips uploaded and aggregated both from BioBase and Insight Genesis mapping services from anywhere across the globe go to Social Map where they are available for viewing and downloading for free to Lowrance, Simrad, and B&G chartplotters (Figures 5 and 6).

Figure 5.  Insight Genesis Social Map coverage of Sweden.

Figure 6. Example map of Anten (Sweden) as viewed from Insight Genesis social map.  Professionals (BioBase) and Anglers (Insight Genesis) can community-source their mapping efforts to “fill-in” unmapped areas and create up to date digital maps for the public.

Second, Fisheries across the globe are threatened by a range of impacts too long to go into detail here and Aquatic Invasive Species are a global pandemic.  Researchers and managers mourn the decline of native aquatic species and often target habitat degradation or loss as a primary driver.  But rarely does information on habitat match the detail of the information on species declines. Citizen Scientists are now helping Natural Resource Agencies fill in the habitat knowledge gaps.  Returning to our example on Ten Mile Lake, now with updated bathymetry provided by TMLA volunteers and data sharing with MN Department of Natural Resources (DNR), Fisheries researchers have precise knowledge about how much cold, well oxygenated water is available for cisco (an important cold-water forage fish for popular gamefish).  Similarly, thanks to the efforts of the Prior Lake Spring Lake Watershed District and citizen volunteers on Prior and Spring Lakes, the response of invasive aquatic plants to watershed and in-lake management actions can be monitored.

Harnessing the power of technology and citizen science to conserve aquatic resources
“Doing more with less” or “working smarter not harder” are common cliché truths that will continue to limit the reach of publicly funded natural resource management programs into the foreseeable future. Through advances in affordable off-the-shelf consumer technology, automation, and the collective enthusiasm of citizen volunteers, good information on aquatic habitat need’nt suffer from declining public natural resource budgets.  Rather, by enrolling the help of citizens and technology such as described here, aquatic biologists and managers can focus their energies on using the information to make wise aquatic resource management decisions.

Recently Published: Aquatic Plant Dominance and BioBase

We are happy to report the first BioBase-focused paper finally published in the peer-reviewed literature:  “Combining hydroacoustic and point-intercept survey methods to assess aquatic plant species abundance patterns and community dominance.” The paper is co-authored by Navico staff and researchers from Minnesota (Donna Dustin), Florida (Dean Jones), and North Carolina (Justin Nawrocki) and published in the January 2015 issue of the Journal of Aquatic Plant Management.  The paper describes a simple technique for combining aquatic plant species presence/absence information with detailed aquatic plant abundance metrics processed by BioBase [EcoSound] from Lowrance sonar logs to generate detailed information on what aquatic plant species are dominating a mapped lake.  The technique has the potential to greatly advance our understanding of the conditions that cause invasive aquatic plants to “take-over” (a colloquial term for dominate) lakes and provide an objective benchmark from which to evaluate aquatic plant management interventions.

Below is the abstract.  Please contact corresponding author Ray Valley (ray.valley@navico.com) if you are interested in a copy of the paper.

Many ecosystem goods and services are derived from aquatic plant–dominated environments and the abundance and composition of aquatic plant communities affects habitat, recreation, angling, aesthetics, and commerce. We describe standardized hydroacoustic methodology that complements species composition surveys and generates comprehensive aquatic plant abundance data with little additional assessment or analysis effort than is already put forth for species surveys. Using data from 22 lakes across the United States, collected by biologists with varying levels of expertise, we compare hydroacoustically derived biovolume with two other semiquantitative measures of whole-lake abundance (frequency of occurrence and ‘‘rake fullness’’). Although we documented some significant correlations between hydroacoustically derived biovolume and frequency and rake fullness, frequency or rake fullness was difficult to interpret biologically on a lakewide scale. We also describe a dominance index that incorporates both species composition and vegetation biovolume to evaluate the degree that a species dominates a local assemblage. We found that the extent of aquatic plant growth and invasive dominance was related to lake productivity with highest biovolume and dominance occurring in mesotrophic to eutrophic study lakes. Using both empirical and simulated data, we also found no significant differences between dominance calculated from a simple metric that gives equal weight to all species at a survey site and a metric that incorporated rake fullness for each species.

How do natural fluctuations factor into your lake management?

Since its inception in 2011, BioBase has helped a large number of lake managers and researchers across the globe create detailed, near real-time aquatic plant abundance maps.  But what happens when “real-time” becomes a “long-time?”  What is the “natural” range of aquatic plant growth in lakes? To what degree does an invasive species change the total plant abundance in a lake over the long-term? Likewise, to what degree does the removal of the invasive through management affect plant abundance within this historical context? These are questions research has yet to answer.   Why not given how much is at stake??

Technological constraints were an initial barrier that Lowrance and BioBase has addressed.  A large consumer technology industry has created affordable and sophisticated sensors and automated difficult tasks collecting and processing the information.

But the second barrier of a commitment to long-term monitoring perhaps presents the bigger challenge to the aquatic and fisheries resource industry.  Evaluations, if they happen at all, are rarely more than a “before-after” snapshot that does not place the differences displayed within a historical context of natural aquatic plant growth. The “before” snapshot in a 2012-2013 comparison might’ve been strikingly different if the project was delayed a year and the before snapshot came in 2013.

With one simple case-study in a Minnesota Lake we present a very visual example of how much aquatic plant abundance changes from year to year in a monitored lake.  We arrived at these results with very little labor input and think they have strong implications for how the aquatic plant management industry approaches management evaluations

The Lake:
Orchard Lake has been Contour Innovations’ (and now Navico’s) “sentinel” lake since July 2011; a demonstration and testing site for developments to Lowrance and BioBase.  You might’ve seen this lake splashed throughout our marketing materials including the Insight Genesis service for anglers. Orchard is a typical 234-acre (94-ha) 31-ft (9.5 m) deep, moderately nutrient-rich Minnesota glacial lake.  Although surrounded by waters infested with non-native Eurasian watermilfoil, Orchard Lake has thus far missed this “bullet” and does not have the species or any other invasive other than the long-established Curly-leaf pondweed (Table 1).

Table 1. Frequency of occurrence of submersed aquatic plant species in depths less than 15-ft, sampled in Orchard Lake, Dakota Co., MN at 94 points spaced uniformly across the lake in July of each year.  Curly-leaf pondweed is the only non-native in the lake as of this writing and this species typically scenesces prior to July in Minnesota.  Most sites were a mix of the listed species and rarely did any one species dominate the local assemblage

The Surveys:
Using Lowrance HDS and BioBase every July since 2011, Contour Innovations/Navico staff have motored back and forth on Orchard Lake logging sonar and since 2012, stopping every 262 ft (80 m) to throw a rake and identify the species that are growing (Figures 1 and 2).

Figure 1. Target 40-m transects and aquatic plant sampling points created in ArcMap (Fishnet toolbox utility) and converted to .gpx and imported into Lowrance Chartplotter.
Figure 2. Actual tracks recorded during one lake survey
Watch Change

Below we display a time-series gallery of processed map images from BioBase from repeated surveys in Orchard Lake along with some basic meteorological summary data (April to July).  Further, we demonstrate a visually intuitive way of describing a historical benchmark from all surveys and compare each repeated survey to the historical average.

2011 – Near normal temperature (0.8 deg F above avg), near normal rainfall (1 in above avg):

Aquatic plant biovolume surveyed with Lowrance HDS and processed by BioBase in July 2011.  Red areas indicate vegetation growing at or near the surface, yellow and green is submerged growth, and blue are areas of no growth.  Avg Biovolume = 49%.

2012 – A warm (5 deg F above avg), wet (4.7 in above avg) summer:

Aquatic plant biovolume in July 2012.  Less growth than 2011.  Avg. Biovolume = 40%. Get the automated BioBase report here

2013 – Near normal temperatures (0.5 deg F above avg), less wet than 2012, but still above average (2.89 in above avg):

Aquatic plant biovolume in July 2013.  More growth than 2011 and 2012.  Avg Biovolume = 53%. Get the automated BioBase report here.

2014 – Slightly cooler than average summer temperatures (-0.7 deg F), and record-breaking rainfall (6.81 in above avg):

Aquatic plant biovolume in 2014.  Lowest growth across all years.  Also the wettest June on record in Minnesota. Avg Biovolume = 37%. Get the automated BioBase report here.

Putting the pictures together: Map Math!

First, using the Raster Calculator in the ArcGIS Spatial Analyst Toolbox (Spatial Analyst Extension required), let’s describe the “average” plant growth condition across all years in order to define our “benchmark” for future comparisons:

Average vegetation biovolume map across all 4 years – 2011 map + 2012 map + 2013 map + 2014 map divided by 4. Regular monitoring of plant growth in untreated reference lakes or bays is needed to incorporate the vagaries of climate and effects on aquatic plant growth.  Averaging maps across all years establishes a “benchmark” condition from which to base future comparisons.

Subtracting 2011 from the average:

Green areas represent higher than average aquatic vegetation growth, blue areas represent lower than average vegetation growth (Avg difference = +3% biovolume – slightly higher than average)

Subtracting 2012 from the average:

Green areas represent higher than average aquatic vegetation growth, blue areas represent lower than average vegetation growth (Avg difference = -5% biovolume; notice the large decrease in the bed along the Eastern part of the lake)

Subtracting 2013 from the average:

Green areas represent higher than average aquatic vegetation growth, blue areas represent lower than average vegetation growth (Avg difference = +7% biovolume; notice a complete reversal of relative growth along the Eastern part of the lake compared with 2012)

Subtracting 2014 from the average:

Green areas represent higher than average aquatic vegetation growth, blue areas represent lower than average vegetation growth (Avg difference = -5% biovolume – lower than average – a see-saw of change!)

Subtracting 2015, 2016….n from average?:

What will next year, and the year after that, and the year after that bring?  Only repeated monitoring can answer these questions


Does excessive rainfall affect aquatic plant growth?

During the time span that surveys on Orchard Lake began, we’ve experienced some wetter than average summers, especially in 2012 and 2014.  Interestingly these happened to be the lowest aquatic plant growth years over the 4 year time span (Figure 13).  Still, with only four survey years, this only begs the question that several more years of monitoring should help answer.

Figure 13. Whole lake average biovolume in Orchard Lake (Dakota Co., MN USA) plotted against rainfall from April to July at Minneapolis/St. Paul International Airport (Data courtesy of the National Weather Service).


Back perception up with real data!
In 4 short years and only 8 days total on the water, we’ve seen how incredibly dynamic aquatic plant abundance is in one eutrophic Minnesota Lake with no aggressive invasive species. These changes would never have been detected by even the most comprehensive species-rake surveys, much less visual surveys!  This is a striking example of the importance of regular monitoring of aquatic plant growth to place results from management within the appropriate historical context.  Lowrance and BioBase makes mapping plant abundance easy so practitioners can focus on the more important question of why differences are being seen.

Need a Custom Map? We’ll make you one!

BioBase’s primary strength is an automated map creation engine designed to take thousands raw of data signals from your Lowrance and rapidly summarize them into informative maps.  These maps have helped aquatic resource professionals throughout the globe make more informed aquatic management decisions.

But BioBase also creates maps that are rather pleasing to the eye and many have asked how they might be able to create customized digital or print maps for their clients.  We offer two solutions that will help you create professional quality maps. First, as ESRI Silver Partners we offer basic support of viewing and analyzing BioBase data in ArcGIS and have produced several do-it-yourself tutorials that are available in your BioBase Support & Resources.  Second, we offer GIS Services to BioBase customers who lack expertise in GIS or the proper software licenses.  Below we present a gallery of images from these projects.  Identities and locations of projects have been changed or omitted to protect the privacy of the customers.

We’ll create a map for you!
Navico offers custom GIS services where interested customers fill out an order form specifying their needs.  Navico GIS staff will transfer the appropriate BioBase data to ArcMap 10.x and any ancillary GIS shapefiles (e.g., sampling waypoints or other points of interest) and produce a custom-sized, high resolution digital map that you can have printed online or at a local print shop.  Email us at info.biobase@navico.com to get print and pricing details.

Multiple BioBase maps can be combined into one map and exported as any image format and custom sized.  Send us your logo and we’ll add it to the map.
Request transparency to the image to show floating leaf vegetation in the aerial imagery. 
Send us points of interest to add to the map.  In this case, navigation hazards in front of a land owner’s property
Send us sediment depth point data and if sufficient, we’ll interpolate and create a sediment depth map (left) and pare it with other BioBase maps (in this case aquatic vegetation biovolume).
Would you like to add water body statistics? We’ll add full lake summaries or summaries by depth.  You tell us the contour interval and units.
An example where a customer desired to simulate the pond depth at a significantly higher water elevation than when mapped with BioBase. Customer used survey-grade GPS to generate precise land elevation data while walking along the soon-to-be-inundated shore.  Customer submitted these point elevation data to Navico along with a high-water shoreline for incorporation into the lake map.

If you have any custom mapping or presentation needs with your BioBase data contact us today at info.biobase@navico.com and we’ll provide you with an order form and generate a quote and delivery timeline for your map.