Diving the Delaware Water Gap
September 25, 2016
• 63° Sunny / 62% Humidity / Wind NNW 5 Mph
• Water Temperature: 70°
• Water Visibility: <20 feet
• Current: negligible - light
On September 25th the Green Divers took part in their first ever Delaware River Dive and it was stunning!
The day began with a full dive briefing conducted by our very own Fresh Water Biologist and River Expert, Erik Sildorf. Erik presented the group with full color, laminated briefing cards that gave the group a great idea of what they would be seeing in regards to plant life, animal life and a cross-section of the river at the specific location.
The in-depth briefing was not only an explanation on what would be seen but what the relationship between each animal and the river was. One of the most interesting relationship was that of the Eastern Elliptic Mussel, the American Eel, and the water clarity! When born, the mussel can only exist in the form of a parasitic life, which means it must latch on to an animal to live. It cannot latch onto fish and survive do to the belief that the fish immune system fights it off; but it can, and only does, latch onto the American Eel. For 2 months the mussel lives as a parasite on the eel, not damaging the eel, but growing until it can sustain life by itself. After about 2 months the mussel drops off and begins to filter the water of the river, providing clarity and stability.
What is so interesting about that? Well the Delaware is one of the only rivers where this happens. In fact, only a few miles to the west, the Schuykill River is murky and does not benefit from the mussels ability to filter. Why? Because the eel population in the Schuykill has been destroyed by hundreds of dams up and down the river, a problem that doesn't exist on the Delaware. Since there are no eels for the mussels to live on, they cannot survive as new life and never go on to become the amazing filter feeders that line the bottom of the Delaware River! In fact, the only mussels found in the Schuykill are over 100 years old!
Also included in the dive briefing and on the card was an amazing explanation what the cross-section of the river looks like. Diving just North of the Water Gap, divers entered the water on the NJ side, right where the river makes a hard turn to the East. This turn causes a unique layout under the water. As the water turns, the current on the PA side is stronger as it has further to travel to complete the turn. This causes 3 very defined differences underwater.
First experienced, was the muddy bottom covered in plants and small fish life. These plants covered everything on the bottom and collected some of the slower moving sentiment causing the muddy bottom and providing a home for small, young, fish. As divers crossed the river to the PA side, they experienced a defined line where the plant life and muck stopped and millions of little river rock cover the bottom. Though the rock had a small dusting of silt, the water was clear and the mussel life abundant. There were no plants, no fish, no muck, as this is where the water current began to pick up and there was no where in this area for fish to hide. Lastly, divers approached the PA side of the river, where the current was the strongest, yet still light and easy to kick through. It was because of this current, that over thousands of years, the river carved through the mountains of the Gap. As it carved it's way around, giant boulders fell into the river. Here divers experienced very little silt but massive rocks and large fish.
The rocks were like a playground as divers would go over and under and through a field of underwater scenery. Large Walleye and Bass watched closely as the divers would flip over some of the smaller rocks in search of food for the fish. The rocks also act as a catch for items traveling down the river in storms. At one location the divers came across a 40-50 foot tree that had found a resting place. Railroad ties and iron pieces of train were found from train accidents that occurred along the river in the 1950s!
The divers continued upstream, against the current and past 1000 ton boulders, some larger than 15 feet high! When it was time to turn around a light current pushed the divers back around the river turn where they than crossed back to the NJ side, experiencing the change from large boulders and fish, to small rocks and mussels, to plant life and young fish. The diving was truly incredible, a fact that honestly surprised many of us who had built our own ideas of what the Delaware River would be like.
Located just 1.5hours North of Underwater World and a drive that takes you up the very scenic 611 river drive, the dive site is easy to get to, easy to dive, and FREE! It is a location that is truly a hidden gem so close to us and one that we will definitely be adding to our dive sites to visit again.
There are 2 important items that need to be noted. River conditions change quickly and our light current and clear visibility could have easily been polar opposites. It is important to understand the river and know when the conditions are favorable and Erik was a great asset to us for that reason. Secondly, the dive is very pretty and interesting but what made it truly amazing is the 15 minute dive briefing that told us a story of what we were going to experience. Again, Erik was an amazing resource that helped to make a good experience a great one. The Green Divers and Underwater World are grateful that we have resources like Erik that truly help make these dive days better than we would have ever imagined when we started this.
For more information on the Green Divers or on this great dive site; visit our website or contact Jeff at firstname.lastname@example.org.