Rodman Reservoir

What to think about the Rodman Reservoir?  The question comes down to do we destroy habitat for one set of animals to create for another?  Not an easily answered question. Some would see the reservoir teeming with life saved for future generations. Others would rather see future generations have a healthier Ocklawaha River. Let's jump into that question.

Here's the background. As far back as 1935 the US Congress allocated money to build the Cross Florida Barge Canal. It would link the Atlantic Ocean with the Gulf of Mexico saving barges the expense of going around the tip of Florida. The final proposed path was to take the St John's River from Jacksonville to Palatka and then go up the Ocklawaha River for a while before exiting for a newly constructed canal. The canal would join the Withlacoochee River which runs to the gulf.

Progress stalled during World War II and President Kennedy got congress to allocate money in the early 1960's to restart construction. It continued off and on with considerable environmental opposition until 1971 when President Nixon killed the project.

Florida Barge Canal Map

In the end it was an estimated 28% complete when killed. Most of the work was dredging projects on the St John's River and raising several bridges over the route.

One thing that was completed was the Kirkpatrick Dam (also called the Rodman Dam) on the Ocklawaha River creating Rodman Reservoir. So why is a dam needed on the Ocklawaha at that point? As far as normal dam functions it's pretty useless. It's not useful for flood control since the Ocklawaha River opens onto the much larger St John's River just below the dam. The dam has no electrical generating capacity. So there's an environmental controversy today about the dam:  To breach or not to breach. That's what I want to discuss today.

Kirkpatrick Dam

I'll give my opinion right at the end, but my goal here is present both the save the reservoir and breach the dam arguments in the best light possible. If anybody thinks I missed part of one side's argument let me know.

The breach-the-dam argument is that the Ocklawaha and the St John's rivers would be healthier without the dam on the Ocklawaha. The St John's River is different than most rivers because of the number of saltwater species that live there. It's common to see rays or mullets much further upstream than the Ocklawaha because there's enough dissolved minerals in the water to support them. The Kirkpatrick Dam stops most migratory fish from going upstream into the Ocklawaha. Mullets are sometimes found upstream of the dam, but not in great numbers.

Another benefit of getting rid of the dam would be for manatees. Each winter thousands of manatees seek refuge from the cold by coming up the St John's river. It's common to see nearly 400 manatees at once at Blue Springs State Park on very cold mornings. Although technically manatees can go through a lock to venture into the Ocklawaha less than 10 per year make that trip. A 2008 survey of the springs on the Ocklawaha show several other springs that could provide cold weather refuge for the manatees if they had better access to the Ocklawaha.

Blue Springs Manatees

The reason for keeping the dam is that the Rodman Reservoir, no matter why it was created is a unique part of Florida now. It's extremely rare in Florida to find freshwater bodies of water that are 30 feet deep like the Rodman Reservoir. The sheer amount of animal life supported in the few miles of Rodman Reservoir is huge. Bassmaster recently rated it the 8th best bass fishing area in the US and the #1 in Florida. And it's not only bass. Where the waters spread out of traditional channel thousands of acres of wetlands have been created. There's no chance that the naturally flowing river would support the sheer number of water creatures that live in the reservoir now. Spreading, slow flowing, and shallow described most Florida rivers prior to dredging for boat traffic. The reservoir come closer to this description than a dredged free-flowing river.

Largemouth Bass

Another reason to keep the dam is that it stops a portion of fertilizer load from upriver. Here's a study by the St John's Water Management District that says removing the dam would increase the phosphorus (fertilizer) load in the St John's River and therefore increase the probability of algae blooms and fish kills near Jacksonville. The increases aren't that big, but with the algae problems in South Florida fertilizer load has gotten lots of attention lately.

So here's my opinion. I probably would be considered a lukewarm breach-the-dam advocate. Giving fish better access to upstream would be a good thing. Giving manatees access to the springs on the Ocklawaha would be a great thing. But at the same time the destruction of a unique and very productive reservoir ecosystem is hard to be a part of. On balance the good that could be done for the entire river slightly outweighs the destruction of the reservoir and its local wetlands. I'd back removal of the dam, but it wouldn't take much more evidence like the fertilizer loads it stops to change my mind. And that's only the environmental arguments and not considering local area economic activity which would probably favor leaving it in place.

Which is why this is a good case where the precautionary principle should prevail, at least for now. As various scientific disciplines weigh in over the next few decades keeping or breaching the dam should be evaluated. It's probably too soon to make an irreversible decision. But that time may come, and the balance is tilted to breaching the dam.