The Red Top Valley Ditch

The North Fork of the Colorado River originates in Rocky Mountain National Park (RMNP) and flows southerly to its confluence with Shadow Mountain Lake in Grand County. Over 90% of the river’s basin is on public land. Shadow Mountain Lake and Lake Granby were built as part of the Colorado-Big Thompson Project in the 1940’s. Approximately three miles upstream of Shadow Mountain Lake along the North Fork Colorado River is the Red Top Valley Ditch Headgate. The 16-mile-long ditch was cut over a five-year period between 1898 and 1903 and, today, supplies irrigation water to area ranches, including the Slash J Ranch and 7V Slash Ranch, and a small portion of the Lambright Ranch.

The ditch was initially conceived and built by Frank Church for his approximately 1500-acre ranch in Grand County. Church was able to recruit other area ranchers to collaborate in the endeavor.  The new ditch was hand dug by a crew of Japanese and Mexican workers—reportedly the same crew that was then digging the Grand Ditch. The Grand Ditch was an 1891 canal project by the Larimer County Water Supply Company of Fort Collins. Its purpose was to source the high tributaries of the North Fork of the Grand River (renamed Colorado River in 1921) and transport the water over Poudre Pass to the Cache La Poudre River and agricultural areas east of the Front Range. Water Supply and Storage Company took over the project in 1895. The Grand River Ditch and the Red Top Valley Ditch were the two earliest major diversions of water from the Colorado River.

In addition to its majority shareholder, the Church Ranch (later Miller-Hereford Ranch), throughout its history, the Red Top Valley Ditch provided irrigation water to the E Diamond H Ranch, the Huddler Ranch (Today, the C Lazy U Guest Ranch), the Slash J Ranch and the 7V Slash Ranch. In the late 1990s, Northern Water bought the Miller-Hereford Ranch (along with its water shares) to build a reservoir on the former ranch property. However, this reservoir was never developed. The ditch ran at full capacity until around 2016. Today it runs at about 2/3 capacity as the former Church Ranch no longer uses ditch water. 

Today, Red Top Valley Ditch (5GA.2773) is an earthen irrigation ditch that is approximately 10-15 feet wide and three feet deep and meanders in a southerly direction for approximately 16 miles. The segments discussed herein include segment 6 (The Red Top Valley Ditch and Headgate and Supply Creek Diversion Gate) and segment 8 (the Stillwater Creek Diversion Gate).

The Red Top Valley Ditch (5GA.2773) was determined eligible for inclusion in the National Register of Historic Places (NRHP) in 2007. Completed circa 1903, the ditch is significant under Criterion A for its association with early settlement and development of agriculture and ranching in the Grand Lake area. In June of 2021, NRCS again determined, and the Colorado State Historic Preservation Officer (SHPO) concurred that Red Top Valley Ditch retained a preponderance of historic integrity and was eligible for the NRHP.

 Colorado Division of Water Resource Records 

The following highlights some of the features of the Red Top Valley Ditch, following it's course from the point of diversion in  The Colorado River  to the Stillwater Creek Diversion Gate. You can scroll through the images or select a point in the inset map below.

Segment 6 of the Red Top Valley Ditch is approximately 6.1 miles in length and includes a Headgate on the North Fork of the Colorado River and the Supply Creek Diversion Gate.

Headgate

The Headgate for the Red Top Valley Ditch is located along the North Fork of the Colorado River along the river’s west bank. The gate sits at the head of the earthen ditch and consists of a singlegate structure measuring 45 feet across (southwest-to-northeast) and 15 feet (southeast-to-northwest).

The Red Top Valley Ditch Headgate was installed around 1900. It is a reinforced concrete and steel structure with two sluiceways. A pair of steel sluice gates are mounted against the central portion of the headgate structure. The headgate consists of a thick poured-concrete headwall with a single northeast wingwall angled downstream to divert river flow away from the bank and serve as a retaining wall to prevent erosion around the headgate structure.

The structure features two equally sized (approximately 9 feet tall by 6 feet wide) cast-in-place reinforced concrete sluiceways made up of two side walls perpendicular to the headwall and a concrete center divider. Each sluice has a poured concrete bed, and the lower portions of the walls (within the flow area) are covered with heavy sheets of plate steel held in place with angle steel brackets spanning the openings. Each sidewall of the sluiceway is buttressed with two channel-steel 45-degree angle brackets (that connect to the downstream side of the headwall) and a vertically oriented piece of angle iron at each of these inside corners. Also, a pair of tubular steel brackets span the upper space between each sluiceway’s outside wall and the central dividing wall.

Each sluiceway has a rectangular steel gate in a welded angle iron frame. Each gate moves up and down along a channel that is located within steel brackets set into the concrete structure (steel slide gate). Gates are surrounded by additional plate steel framing and reinforcing components. Each steel sluice gate is equipped with an actuator to raise or lower the gates to control the flow of water within the ditch. The west gate has an electric motor (Rotork) actuator. This automated device is mounted atop the original mechanical actuator’s housing and its controls are located in an electrical box mounted to the western downstream side of the headwall. The east gate actuator is the original mechanical variety and is crank operated. The cast iron mechanical actuator housing is stamped with the manufacturer maker's mark: “Armco MFG Denver 2042A.” These actuators articulate a jack screw (threaded gate stem) that is welded to the large steel gate. Both actuators are mounted atop the headwall on a set of repurposed standard gauge railroad tracks.

Mounted atop the headwall over the gates and atop the lower sluice walls below the gates on the downstream side are tubular steel handrails to provide pedestrian access to the structure and its controls. Each railing has an associated wood plank walkway.

The ditch segment and headgate remain mostly in original condition. The only alterations are some concrete repairs (skim coating) and the addition of some updated steel components. The new automated gate actuator was installed around 2015.

Supply Creek Diversion Gate

The Supply Creek Diversion Gate is located approximately 500 feet south of the confluence of Supply Creek and Red Top Valley Ditch. The gate splits the channel into two equally sized streams approximately 10-15 feet wide by three feet deep. The resource consists of a single gate structure measuring 25 feet across (west-to-east) and 12 feet deep (south-to-north).

The Supply Creek Diversion Gate was installed in the 1960s and replaced another concrete structure of similar design. This diversion gate is composed of two pairs of reinforced concrete sluiceways that divide the Red Top Valley Ditch/Supply Creek into two separate streams with Supply Creek continuing due south and Red Top Valley Ditch continuing southwest. The pair of sluiceways on the east side (Supply Creek side) of the structure are composed of a wing-walled concrete abutment at the east bank of the creek and a centrally located concrete bulwark that serves as both abutment and retaining wall. The sluiceway is separated into two equally sized openings by a reinforced concrete divider. This entire section of the structure sits atop a thick poured concrete bed. Each sluice features a vertical slot cut into the concrete to house the wooden planks that serve as the sluicegates. The pair of sluiceways on the west side (Red Top Valley Ditch side) mirror those on the east side.

The Supply Creek Diversion Gate remains mostly in its original 1960s condition. A few remnants of the former pre-1960s gate structure can be seen on the downstream side of the west gate. These are composed of three rectangular concrete slabs strewn along the sidewalls of the ditch.

Segment 8 of the Red Top Valley Ditch is approximately 121 feet in length and includes the Stillwater Creek Diversion Gate.

Stillwater Creek Diversion Gate

The Stillwater Creek Diversion Gate is located at the confluence of Stillwater Creek and Red Top Valley Ditch. The gate splits the channel into two equally sized streams approximately 10-15 feet wide by three feet deep. The overall dimensions of the structure are 25 feet (west-to-east) and 25 feet (south-to-north).

The Stillwater Creek Diversion Gate was installed in the 1960s and replaced another concrete structure of similar design. This diversion gate is composed of two pairs of reinforced concrete sluiceways that divide the Red Top Valley Ditch/Stillwater Creek into two separate streams with Stillwater Creek continuing due south and Red Top Valley Ditch continuing west. The pair of sluiceways on the south side (Stillwater Creek side) of the structure are composed of an angular concrete abutment (with a southeastern wing wall) at the east bank of Stillwater Creek and a centrally located angular concrete bulwark that serves as both abutment and retaining wall/erosion control. The sluiceway is separated into two equally sized openings by a reinforced concrete divider. This entire section of the structure sits atop a thick poured concrete bed. Each sluice features a vertical slot cut into the concrete to house the wooden planks that serve as the sluicegates. In addition to the slots, each of the south sluiceways feature two heavy steel brackets with vertical slots for a steel gate. These brackets are bolted directly to the concrete. The pair of sluiceways on the structure’s west side (Red Top Valley Ditch side) mirror those on the south side. However, the west side still utilizes the slots in the concrete for wooden plank gates. This section does not have steel brackets for steel gates. Both pairs of sluiceways are bridged with steel mesh planks for traversing the structure.

Credits: Content provided by HDR, Inc.

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