Rock River – East Branch – Theresa

Most Rock River paddlers either do its lower portions or Horicon Marsh.  Upstream of Horicon, the Rock splits into multiple branches which despite being fairly obscure are actually more interesting IMO.  My favorite of these is the “East Branch” which I had paddled twice before and was long overdue on my todo list to explore in more depth.

I started the trip at N. Pole Rd, where there is a fantastic canoe/kayak landing at the base of a large drumlin.  This is serviced by a large public gravel parking lot that sadly few use.  The launch area is just downstream from the Theresa Marsh State Wildlife Area.  This could be thought of as a “baby Horicon Marsh” and I do want to eventually explore it in the future.  Currently the marsh dam (located just upstream from N. Pole Rd) is wide open and the reservoir drawn down for “vegetation management” (likely to kill invasive cattails) and to perform dike repair.  The marsh is scheduled to be dammed up again later in 2021.

The first mile (N. Pole Rd to River Edge Park) featured a slow, wide, and open channel.  That may sound boring, but it was actually kind of nice.  Highlights included some bankside marsh plants, waterlilies, and drumlins visible in the distance.  This area of Wisconsin is famous for its drumlins (glacially elongated hills) and has the highest concentration of them in the entire world.

The next half mile (River Edge Park to the dam) flowed through downtown Theresa.  Despite being an urban paddle this was really nice with old trees arching over the river and tastefully created embankments that protected the shoreline from erosion and mud.  The dam required portaging which can be done on the right bank.  The portage path is unfortunately through someone’s lawn, but state law says it’s perfectly legal to do this…either way I wouldn’t dawdle with your portage.  Downstream from the dam there are public parks on both sides of the river and it was an easy reentry.

The subsequent half mile (dam to sanitation plant) was the shallowest part of the trip.  Here the river flowed quickly past the last outskirts of Theresa and featured a number of minor rapids/riffles.  For the Rock River this is a real treat, as the lower Rock has few if any rapids.

The next three miles (sanitation plant to Hwy AY) was a great part of the trip.  For about a mile and half the river flowed between massive drumlins and over a surprisingly rocky substrate that featured several small boulder gardens.  The Rock River was living up to its namesake!  Despite this being farm country, there were nice woods positioned next to the river.  Closer to AY the river valley opened up, the river slowed down, and things became less interesting. 

On the downside there were 4-5 tires in the river.  Scientists have recently discovered that as tires break down they release 6PPD which is quite toxic to fish and other small marine animals.  Hopefully we’ll see more river cleanup efforts in the future to remove tires from our watersheds.  Another disappointment was seeing the number of dead ash trees…this is the third Eastern Wisconsin paddle in a row in which I’ve seen massive ash tree carnage (courtesy of the emerald ash borer).

The last half mile+ (Hwy AY to Gill Rd) was a short leg, which despite encroaching farm fields, featured some nice woods.  There were no logjams for the entire trip (had I realized this I would have done this trip long ago).  I did see chainsaw work so I suspect locals keep this route open.  The only downed tree had a gaping hole under it and was super easy to get through.  I ended the day at Gill Rd which was a bit weedy, but was a doable bridge access.

In summary this was a good trip that I enjoyed.  Because the current is slow above the Theresa dam, round trips on that leg are viable and something locals who aren’t into shuttling might consider.  While I took out at Gill Rd, much of the East Branch downstream from there (and in fact all the way to Horicon) is great for paddling.  Personally I would like to explore the Theresa Marsh (Hwy D to N. Pole) for a future trip which I suspect could be scenic and maybe even a nicer paddle than Horicon.

Noteworthy Wildlife:

Sights included a great blue heron, a green heron, an eagle, many dragonflies, and clams.  The most prolific animal though were the carp (common both above and below the Theresa dam).  They are strange fish…not only are they atypically large, but they make strange noises and partially surface to slurp up pond scum.   When spooked in shallow water they would shoot around like jet boats.

Local Diversions:

Ledge Park:  This is a county park, but IMO rivals many state parks.  The highlight is a scenic vista overlooking parts of Horicon Marsh.

Put-in:

North Pole Rd Landing:  This is a great public landing that hardly anybody uses.  Parking is plentiful, free, and the area is private.

Alt Put-ins:

• Ridge Edge Park  (1.3 miles downstream from North Pole):  This is also an excellent public landing.  An outhouse is available in the park.  I suspect this launch sees mostly round trips from paddlers heading upstream to the marsh or downstream to the dam.
• Theresa Dam/Park  (1.8 miles downstream from North Pole):  There’s actually public access locations both north and south of the dam…but the park south of the dam is much nicer with good street parking.  Despite being a nice launch option, I suggest launching at North Pole Landing instead as the leg upstream from the dam is nice.

Take-out:

Gill Rd (East Bridge):  This is not a great access but is doable.  For starters the shoulders are steep for parking and you’ll likely have to park your car a couple hundred yards from the bridge.  Then the banks are weedy and there is mud in spots.  Although in hindsight I chose a bad take-out spot by the bridge and there were easier corners of the bridge to disembark from.

Alt Take-outs:

• Hwy AY:  (0.7 miles upstream from Gill Rd East)  I didn’t scout this bridge in depth.  It seemed weedy but doable…likely same difficulty as Gill Rd (East Bridge).
• Gill Rd (West Bridge):  2.5 miles downstream from Gill Rd East)  I didn’t scout this in depth, but think it would be a doable access.  The first half of this bonus leg is boring…but the second half shifts north and is really nice (clear water, rocky, fast).

Shuttle & Rental Information:

Bike Shuttle – Gill Rd to N. Pole Rd:  4.6 miles with 72′ of ascent.  There are some minor hills, but this is mostly a pretty easy bike shuttle.

Hazards, Logjams and Current:

Logjams:  None…there was one downed tree, but that was super easy to get under.

Current:  Before the dam it was slow to non-existent.  But downstream from the dam the river moved at a decent clip with a number of riffles.

Rapids:  There were a large number of light riffles, but nothing serious.

Dam:  The dam in Theresa must be portaged which can be done on the right/north bank.  A concrete step has been cut into the retaining wall, so paddlers can do a dock style dismount.  Note some paddlers are not comfortable doing deep water dock style dismounts, so having another paddler to help stabilize your boat while you get out might be helpful.  This portage is across somebody’s lawn, but Wisconsin law allows you to legally portage a dam no problem.  Re-entry is very easy below the dam.

River Depth and Navigability:

Nearest Gauge – Rock River @ Horicon:  Trip was done at 145 CFS or 6.67′.  This gauge is downstream from several dams so may not be perfectly representative.

• < 101 CFS:  Maybe too shallow.
• 101-200 CFS:  99% of the river would be navigable, but there will be a handful of ground-outs that required scooching or wading.  I consider this worth it though.  The shallowest part is a half mile leg between the Theresa dam and the sanitation plant.
• 201-300 CFS:  A good target range.
• 301-500 CFS:  A decent range, but some of the nice boulder gardens might be submerged and the clarity will likely be gone.
• 501-800 CFS:  The river is likely muddy and loses a lot of its magic at this depth.  It’s likely still practical for padding though.
• 801+ CFS:  Maybe too high for enjoyable paddling?

Detailed Overview

Trip Map

Overview Map

Video

Photos

Size:

Starting the trip at North Pole landing which is behind a huge drumlin

Nice launch

Morning dew

View from bridge

Same view, but spring

River starts wide and slow

Attractive lilies

Slow current...this stretch can be done as a round trip

Farm on top of a drumlin

River is redirected sharply right here by as drumlin

Photogenic reflections

A muskrat lodge

River Edge Park is a viable access

Paddling through the town of Theresa

Very nice

Most of the shoreline in town was neatly manicured and mud-free

Hwy 175

View from bridge

Portaging the Theresa dam

Bottom side

A number of light rapids after the dam

And rock bars

Looks like I'm not the first to kayak this stretch

One of the shallowest parts of the river

There were countless water striders

More riffles

River gets somewhat deeper after the sanitation plant

Entering a wooded stretch

Great blue heron

This scenic part of the river was sandwiched between two large drumlins

One of many glacial erratics

Ok clarity in spots

Many of the rapids were shallow

Huge collection of grapevines

Damselflies were a common sight

Rock River living up to its namesake

Hwy AY

Shallow spot

More nice woods

Exposed tree roots

A shady trip

One last erratic

Taking out at Gill Rd

A bit weedy

Shoulder parking isn't good but is doable

Scouting Theresa Marsh...future trip!