How to start the exploration of a new dive site

[Rich Keller]

160 acre lake is too big to survey by diving alone. The low tech way to do this is with a boat and depth finder. If you do not have a GPS set markers along the shore line and run a pattern using them as reference. Have weights with lines attached to floats on hand and through one over at every contact point so you can go back later to check each one out. Start with the side of the lake closest to the road as you will get the most use out of that area once it is developed. You should find a roadway from that general area that leads down to the bottom of the quarry. At the bottom of that roadway should be most of what was left behind if anything. Can you tell me where this quarry is located? GPS numbers would make it easy for me to find on Googol Earth.

 

[emoreira]

Thanks to all for the interesting and wise advises.
I've made a better picture of all the work that will be involved.
Even if the place cannot be used for diving, placing houses around the lake involve many of the tasks described just for safety of the people living near the lake.
It's always a pleasant thing to post questions here.

 

[emoreira]

160 acre lake is too big to survey by diving alone. The low tech way to do this is with a boat and depth finder. If you do not have a GPS set markers along the shore line and run a pattern using them as reference. Have weights with lines attached to floats on hand and through one over at every contact point so you can go back later to check each one out. Start with the side of the lake closest to the road as you will get the most use out of that area once it is developed. You should find a roadway from that general area that leads down to the bottom of the quarry. At the bottom of that roadway should be most of what was left behind if anything. Can you tell me where this quarry is located? GPS numbers would make it easy for me to find on Googol Earth.

Here they are :
-34.398128, -58.910408
You will see two quarries. The urbanization project involves the union of both, a lot of materials will be removed from the quarries to unify them.

 

[DaleC]

Hi Emoreira,
I do a lot of diving as you are describing in uncharted lakes and if you click on the link in my sig line I am also involved in a more in depth project for one specific lake. I can offer a few suggestions.

The Fishfinder/depth sounder is a good idea if you have access to a boat with one. This will help you determine the general profile of the bottom and to detect any large objects or features.

Do some research and see if you can't find a bathymetric map for the lake. This shows the depth contours. It would save you a lot of groundwork.

Break your lake up into sub sections to tackle one at a time instead of trying to map a whole lake at once. Then you can descibe each area in more detail and focus your efforts better.

I generally do two types of exploratory dives. The first is a straight down descent from the shore to determine the slope profile, littoral/benthic zone interface and bottom composition. Once I do this I usually swim around a bit and then ascend at a different spot to see what the slope is like there.

Next I dive down from the same access point to a desired depth and follow that depth contour in one direction till I reach my turn pressure, ascend to a shallower predetermined depth contour and follow that back to my exit point. For example: Descend to 60', swim that contour, turn, ascend to 30', swim that contour back to start, exit. By doing this repeatedly you can soon develop a general understanding of the basic features of the lake and plot them on a map. What you miss are the open water portions but those really need to be covered with the fishfinder/depth sounder first.

Using GPS and marker bouys sounds cool but it isn't really neccisary until you are well on your way to creating a defined overview of the area. It's best to go from known to unknown systematically and not just swim around willy nilly hoping to bump into something to mark. First it's just old fashioned foot (fin) work. The only time you might need to mark something from the surface is if you come across something unique while swimming the contours. I did this a while ago when I found portions of an old Bailey bridge. I knew the depth but not the position in the water. In that particular case I just did a short dive wherein I swam to the object underwater, located it, swam directly upslope to the surface, and found a reference point on land. Problem solved.

Be sure to observe the shoreline first to see if there are any barriers to exiting earlier than intended if you need to.

I don't know about your region but in my area the biggest dangers posed in lakes are hypothermia due to cold (especially under the thermoclines), entanglement in fishing line and entanglement in tree limbs (due to low vis conditions). In the summer, it is being hit on the surface by boaters.

Good luck with your efforts if you choose to go ahead. Let me know if I can help in any way.

Dale.

 

[mjr0112]

Have fun mapping that monster, maybe find a few local dive team members for some help?

 

[DaleC]

Looking at that location, the quarry entrance appears to be in the NW corner of the more eastern lake (closer to the nearby small housing development). There also appears to be two old dilapidated buildings/foundations on the southern end of the western lake that may have had something to do with the quarry operation.

Pretty cool quarry site.

 

[emoreira]

Looking at that location, the quarry entrance appears to be in the NW corner of the more eastern lake (closer to the nearby small housing development). There also appears to be two old dilapidated buildings/foundations on the southern end of the western lake that may have had something to do with the quarry operation.

Pretty cool quarry site.

Yes, those constructions are part of the old mining company. And it seems that the access ramp can be seen easily.

 

[wve]

As far as figuring out how to turn a quarry into a dive business, you may want to visit with these folks.

I may have contact information at home, but I'm at work right now. (Well, I'm supposed to be working...) If I can find it, I'll post it or send it to you.

 

[Rich Keller]

Here they are :
-34.398128, -58.910408
You will see two quarries. The urbanization project involves the union of both, a lot of materials will be removed from the quarries to unify them.

It might not be a good idea to unify the quarries. Depending on what you find below it might make sense to have one set aside for diving & swimming and the other for mixed use like boating & water skiing. With the land bridge in place it will also give you easier access to both not to mention reduce your costs in developing the site. I do not see any water flowing into or out of the quarry. What is the water condition like? How is it being feed? Any idea what the exchange rate of the water is if any?