Skip to main content

Harmon Tunnel - Pammel State Park, Iowa

 



Madison County, Iowa is known for their covered bridges, romanticized by print publications and even movies. But did you know that Madison County is home to Iowa's only highway tunnel? Located at the Pammel State Park just to the southwest of Winterset is the Harmon Tunnel. But what's the deal with the tunnel, you may be asking yourself.

Built in 1858, the Harmon Tunnel was originally dug by William Harmon and his sons as a small chute in order to carry water that was diverted from a nearby bend in the Middle River to power a saw mill which was later converted into use as a grist mill. While the mill was closed and abandoned in 1904, the tunnel was expanded to allow vehicular traffic in 1925, just in time for Pammel State Park to open in 1928. The Harmon Tunnel has since been expanded and reinforced to accommodate modern vehicles.

The Harmon Tunnel was originally designed to pass through the narrowest part of the horseshoe bend of bedrock and a limestone ridge that natural limestone ridge that was about 100 feet high. While the tunnel was originally narrow in order to accommodate the water chute for the mill, it is now 147 feet long, 15 feet high, and 40 feet wide. The tunnel accommodates two way traffic along with sidewalks for pedestrian travel. Within Pammel Park, there is also a ford of the Middle River where vehicles can cross the river to access other parts of the park, except during periods of high water (which is what I encountered during this visit to Iowa) and also in winter.



How to Get There:



Sources and Links:
Bridgehunter.com - Harmon Tunnel
Madison County Parks & Conservation Center - Historic Features in Pammel Park
Only In Your State - Most People Have No Idea This Unique Tunnel In Iowa Exists

Comments

Popular posts from this blog

Yes, the color of your nearby fire hydrant matters...

...and here's why. You will find White, Red, Yellow and Violet colored fire hydrants pretty much everywhere.  But there's a reason for this - and it's because of the National Fire Protection Association (NFPA).  This association has issued guidelines for color coding standards for fire hydrants.  These color codes from the body of the hydrant, top of the hydrant, and in some municipalities the outlet caps are designed to allow fire fighters to know what type of system, water flow rate (Gallons Per Minute or GPM), and level of water pressure.  This guideline is known as NFPA 291 and is intended to be used universally throughout the United States. The NFPA guidelines are specific to the body and the top cap of the hydrant.  If a hydrant is WHITE or YELLOW - it means that it is connected to a public/municipal water system.  If a hydrant is RED - the hydrant is connected to a private system, typically a well.  These are most common in rural or unincorporated areas

Phase 1 of the California State Route 132 West Expressway (in the making since 1947)

On September 15, 2022, the Phase 1 of the California State Route 132 West Expressway opened in the city of Modesto from California State Route 99 west to North Dakota Avenue.  Phase 1 of the California State Route 132 West Expressway was built upon a corridor which was tentatively to designated to become the branching point for Interstate 5W in the 1947 concept of the Interstate Highway System.  The present California State Route 132 West Expressway corridor was adopted by the California Highway Commission on June 20, 1956.  Despite almost being rescinded during the 1970s the concept of the California State Route 132 West Expressway corridor lingered on for over half a century and became likely the oldest undeveloped right-of-way owned by California Transportation Commission.  Pictured above is the planned California State Route 132 freeway west of US Route 99 in Modesto as featured in the May/June 1962 California Highways & Public Works.   The history of the California State Route

Aptos Creek Road to the Loma Prieta ghost town site

Aptos Creek Road is a roadway in Santa Cruz County, California which connects the community of Aptos north to The Forest of Nisene Marks State Parks.  Aptos Creek Road north of Aptos is largely unpaved and is where the town site of Loma Prieta can be located.  Loma Prieta was a sawmill community which operated from 1883-1923 and reached a peak population of approximately three hundred.  Loma Prieta included a railroad which is now occupied by Aptos Creek Road along with a spur to Bridge Creek which now the Loma Prieta Grade Trail.  The site of the Loma Prieta Mill and company town burned in 1942.   Part 1; the history of Aptos Creek Road and the Loma Prieta town site Modern Aptos traces its origin to Mexican Rancho Aptos.  Rancho Aptos was granted by the Mexican Government in 1833 Rafael Castro.  Rancho Aptos took its name from Aptos Creek which coursed through from the Santa Cruz Mountains to Monterey Bay.  Castro initially used Rancho Aptos to raise cattle for their hides.  Following