Whales at Powell

We just returned from a glorious trip on the lake. We took the houseboat from Bullfrog up to the end of Iceberg and then boated from there up to our favorite canyons in Escalante. One thing that really stood out to me this trip at this lake level is the number of barely submerged rocks (whales!). People seem to get really fussed up when the lake level goes low but in reality, the water shrinks closer to the primary river channels. Most of the whales we ran into oops, I mean saw this trip were the typical ones extending out from points sticking into the channel but there were several other, less expected ones. One in particular was in the main channel, before rounding the corner into SlickRock canyon, with the inflow rate, its probably safe now but... there will be new ones created.

Any newcomers to the lake should especially be aware of this. I always wear polarized glasses to take the glare off and help me see, I also use GPS and pretty much stick to the river channel. I use sonar extensively but it is best used to monitor depth going slow at the upper end of the canyons. At 30 mph or so you'll discover the rock long before the sonar sees it out in the channel. Not meant to lecture, just hope this is helpful and saves someone from a really bad experience.

Anyway, great trip. Cathedral in the Desert is right at the top of the first fall into the main cathedral. The sand bar at the mouth of 50 mile is covered but stay to the right when inbound. Hope you all have a great time!
 

ScottF

Well-Known Member
The Navionics app shows the lake bottom in 10' contour lines, as below. You set the actual lake level on your app then the map is adjusted for that level, clearly marking the whales as you see below in yellow. It tracks your position on the map with GPS - no cellular connection required. I've checked it many times against my depth finder and they match within a few feet. It is automatically updated for changes to the lake bottom, to the extent users also have a depth finder connected and allow their data to be uploaded to Navionics (obviously, not on your phone but on the main navigation unit on a boat.)

The map is useful for all navigation. You can zoom out to see the entire lake or zoom in to see very precisely where you are and what the bottom contour is. Mile markers are shown and canyons are named. I have an expensive Raymarine on my cruiser, but the app on my phone/ipad is better.

When was the last time you used a paper map in your car? Why would you use one on your boat?

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ScottF

Well-Known Member
Do you know if we could hook the app to our Malibu depth finder?
You couldn't use the Navionics app on your iphone/ipad and have it hooked up to a depth finder on your boat. Of course you could purchase a navigation unit from Raymarine or Garmin which would show the same Navionics maps and would hook up to the depth finder on your boat.
 

Cliff

Well-Known Member
OK went and looked at the app bur haven't found how to set lake water level anywhere
How is that done?
 

ScottF

Well-Known Member
Cliff, to set the lake water level in the Navionics app I first look it up in the Lake Powell Water Database, 3609' today. Then I go into Menu in the Navionics app and select Map Options. Under Map Options make sure that Water Level Correction is turned on. Next, since the app defaults to 3600' for Lake Powell I set the Water Level slider to +9'. You can also fiddle with the sliders for Shallow Area, Depth Shading and Depth Contours to get the map looking the way you want.

With the pics below you can see what one area of Padre Bay looks like set to a water level of +9/3609 (be careful, but usable) and what it looks like at -10/3590 (totally unusable). With the sliders you can define what level of safety you want indicated on your map, e.g., "warn me away from areas less than 10' deep", or "warn me of those less than 50'.

The app also has a Route feature, shown on the third pic, with Automatic, Manual, or Previous Route options. I haven't used this feature, but I believe that in Automatic you set your start point (e.g. AP Marina) and your end point (e.g., favorite spot in Last Chance) and it shows the fastest safe route. So, on your phone/pad you just follow the route it sets, or on your Raymarine/Garmen it appears to be self driving (probably good for the open ocean but not for Lake Powell). Again, I've haven't used this feature, only read snippets about it.

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Here’s a simple way to look at this, The Thalweg of a river is the deepest part of a river and the outer edge of a turn is where the most water naturally flows, so the outer edge will be the deepest, and the inner edge of the arc will be the shallowest. Take a look at this next time your’re cruising the channels.
 

gznokes

Well-Known Member
Cliff, to set the lake water level in the Navionics app I first look it up in the Lake Powell Water Database, 3609' today. Then I go into Menu in the Navionics app and select Map Options. Under Map Options make sure that Water Level Correction is turned on. Next, since the app defaults to 3600' for Lake Powell I set the Water Level slider to +9'. You can also fiddle with the sliders for Shallow Area, Depth Shading and Depth Contours to get the map looking the way you want.

With the pics below you can see what one area of Padre Bay looks like set to a water level of +9/3609 (be careful, but usable) and what it looks like at -10/3590 (totally unusable). With the sliders you can define what level of safety you want indicated on your map, e.g., "warn me away from areas less than 10' deep", or "warn me of those less than 50'.

The app also has a Route feature, shown on the third pic, with Automatic, Manual, or Previous Route options. I haven't used this feature, but I believe that in Automatic you set your start point (e.g. AP Marina) and your end point (e.g., favorite spot in Last Chance) and it shows the fastest safe route. So, on your phone/pad you just follow the route it sets, or on your Raymarine/Garmen it appears to be self driving (probably good for the open ocean but not for Lake Powell). Again, I've haven't used this feature, only read snippets about it.

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ScottF This is a really helpful explanation. I have wondered how to use this water adjustment feature but never knew that the baseline was 3600 feet. Just out of curiosity, where can I see the default lake level in case I forget?
 

birdsnest

Well-Known Member
Here’s a simple way to look at this, The Thalweg of a river is the deepest part of a river and the outer edge of a turn is where the most water naturally flows, so the outer edge will be the deepest, and the inner edge of the arc will be the shallowest. Take a look at this next time your’re cruising the channels.
That idea doesn't work at Powell because of spires,buttes and other odd formations native to this lake. West Canyon is one of the best examples of rocks being where they are not supposed to be. Attention to yellow water and a good water level adjust sonar or app are essential to safe navigation at Powell. I know what you are saying and virtually all the rivers in the east and south abide by your scenario. The channel at Powell is wherever it wants to be and even then whales can be lurking very close to the edge of the channel or even in the channel. Ten years working on the lake and a few props back me up. (ain't proud about the props but I had a weird job that exposed me fairly often). No dirty minds allowed!
 

bdn

Well-Known Member
One of my Powell pastimes is to mentally remember whale near misses from past years and look for them at lower lake levels. One stand out is in Rock Creek that is a dangerous whale at 3610’ that is over 200’ from the shoreline and not where you would ever expect it to crop up.
I agree with birdsnest that West Canyon can be particularly dangerous.
 

dhendoo

Member
bdn, know exactly which one you're talking about. Saw it 2 years ago at that exact water level, same as today's actually. Was piloting the houseboat from up top, middle of the bay, looked over and said, "Make a note of that one, that will ruin a trip." Definitely would not expect it that far out, and could easily see someone coming up on it quickly.
 

bdn

Well-Known Member
20-25 years ago I was pulling my young daughter on a slalom ski at 35 mph, occasionally looking back at her, and had the closest near miss with that whale - throttled down, turned and missed it by a couple of feet. Didn’t see it because of the angle of the sun until the last second. Would have been a disaster at that speed. I still shake and shudder when I think of what might have been if I hadn’t spotted it because I was looking back.
 

birdsnest

Well-Known Member
That particular whale has given our group of fishermen with multiple boats more than one OMG moment. It's interesting to stop and look at all the stitches those rocks have.
 

Meatwagon

Well-Known Member
:eek:I can remember almost tossing my dad and brother overboard on the way into west canyon years ago when I had to take a hard right to avoid the yellow Water that I couldn't see until it was almost to late . It only takes one or two of those events to gain a whole new respect and caution while boating on the lake. Same goes for the wind and the tour boats. Be mindful all the time your on water.
 
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