Fish ladders and boat chutes part of a massive dam rebuild on the #ArkansasRiver — @ColoradoSun

Homestake Arkansas River Diversion. Photo credit: Colorado Springs Utilities

From Colorado Springs Utilities:

Project Overview / Background

The Homestake Project is a trans-mountain raw water collection, storage, and delivery system co-owned and operated by the cities of Colorado Springs and Aurora, Colo.

The Homestake Arkansas River Diversion (ARD), between Granite and Buena Vista, Colo., was constructed in 1964 as the original intake for the Otero Pump Station. Water is now primarily withdrawn from Twin Lakes, however the ARD remains an alternate point of diversion. The ARD has deteriorated and requires repair. The ARD was not originally designed as a navigable facility.

Colorado Parks and Wildlife (CPW) manages the Arkansas Headwaters Recreation Area (AHRA) which includes the site of the ARD. CPW expressed interest in partnering with Springs Utilities on a rehabilitation project to include a boat chute for downstream navigation as this location is currently considered the only non-navigable reach of the Arkansas River between Leadville and Canon City, Colo.

The Upper Arkansas River is both one of the most heavily used rivers in the United States for whitewater recreation and is a Gold Medal Trout Fishery. The river is managed to support multiple objectives including water supply and delivery and outdoor recreation.

The cities of Aurora and Colorado Springs are constructing a rehabilitation project that will replace the intake and diversion, provide a boat chute for downstream navigation, and provide upstream fish passage for spawning of brown and rainbow trout. The project also included improving river safety for recreational users and providing whitewater boat portage. User safety was an extremely important design consideration.

A physical model was constructed to test and refine hydraulic elements to optimize performance, maximize user safety and meet design guidelines for recreational whitewater for all three components: boat chute, fish passage and the new intake structure.

The $9 million construction cost of the project is being jointly funded by the cities of Aurora and Colorado Springs. $1.2 million in grants is coming from Colorado Parks and Wildlife and the Colorado Water Conservation Board through grant funding to support the Colorado Water Plan (Water Supply and Demand Gap and Environmental and Recreation Grant Programs). The Pueblo Board of Waterworks is donating the easements necessary to construct and maintain the diversion.

Here’s a report from Jason Blevins writing for The Colorado Sun:

But just below the former riverside mining camp of Granite, where a dilapidated dam built in 1964 has long blemished the Arkansas River’s beauty, rebar jutted from concrete blocks, preventing raft passage and spawning trout battled the steep wall of blasted rocks to reach upstream pools.

“Not a lot of thought went into recreation or fish when this dam was built,” said Ronald Sanchez, an engineer with Colorado Springs Utilities.

A lot of thought is going into fish and recreation now, as water managers in Colorado Springs and Aurora join the Colorado Water Conservation Board, the Pueblo Board of Water Works, Colorado Parks and Wildlife and the Arkansas Headwaters Recreation Area in rebuilding the diversion that directs water to the Front Range.

The $9.1 million project will make the entire river from Leadville to Cañon City navigable for rafts for the first time in at least 55 years.

It’s part of the vast Colorado Springs- and Aurora-owned Homestake Project that brings Eagle River Basin water from the Holy Cross Wilderness to the Arkansas River Basin, through the Homestake, Turquoise and Twin Lakes reservoirs for delivery to the Front Range cities.

The cities started construction of the Arkansas River diversion in July 2018, creating three distinct channels below a rebuilt intake that serves as a backup water diversion to the Otero Pump station downstream of Twin Lakes Dam. Before the Twin Lakes Dam was built in the late 1970s, the diversion was the original intake that collected and directed water to the Otero Pump station for delivery to Aurora and Colorado Springs.

One channel is a fish ladder for spawning brown and rainbow trout. Another channel is a spillway to accommodate flood-level flows like the ones that swelled the Arkansas River this spring. And a third is a series of six drops allowing rafts safe passage.

The project marks a new era of collaboration between the diverse interests on the Arkansas River between Leadville and Cañon City, one of the most recreated stretches of river in the U.S.

“For me the coolest thing about it is that you have these large water utilities in Colorado going above and beyond to do the right thing for the next 50 years,” said Salida-based whitewater park engineer Mike Harvey.

Ten years ago, Harvey helped the Arkansas Headwaters Recreation Area craft a report urging Aurora and Colorado Springs to consider recreation and fish when it came time to rebuild the Granite Dam diversion…

The Arkansas River accounts for more than $74 million of the $177 million in economic impact created by commercial rafting in Colorado. The 102 miles of river in the Upper Arkansas River Valley also ranks among the 322 miles of Colorado waterways that qualify as Gold Medal Fisheries that can yield a dozen large trout per acre. It also supplies a large percentage of water to Colorado Springs and Aurora via the 66-inch pipeline that runs from the Otero Pump Station.

Rebecca Mitchell, the executive director of the Colorado Water Conservation Board, said the project exemplifies the collaboration of the Colorado Water Plan, which gathered perspectives from all types of water users in the state to create a policy roadmap for future water planning across the state.

Colorado Parks and Wildlife and the conservation board provided $1.2 million in funding through Colorado Water Plan grant programs.

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