A Changing Landscape: Restoring Hallam Lake

ACES Staff

September 16, 2021

A Changing Landscape: Restoring Hallam Lake

History of Hallam Lake

Hallam Lake is the most wild place in Aspen, but it is also a place with deep human history. For thousands of years before miners arrived, the Ute People spent summers in the upper Roaring Fork Valley. At that time, the area we now know as Hallam Lake was a series of wetlands and springs. It was also one of the many places the Ute almost certainly visited to find food and shelter. In the 1880s, miners arrived, forcing many of the Ute off of their native land. In the midst of Aspen’s rise as a silver mining town, an earthen dam was constructed to impound the many springs and upwellings that created the wetlands. This led to the initial creation of the Hallam Lake we know today. 

Since its creation, Hallam Lake has served as a recreation site, a fish hatchery, an ice harvesting area, horse pastures, and now, as a nature preserve. Over time, the wildlife that inhabits Hallam Lake adapted to this altered ecosystem. Fish, beaver, and muskrats find refuge in the lake’s water. In the summer, swallows come by the thousands to eat insects that hatch from the water each morning and night. Migrating waterfowl find the ice-free surface of Hallam Lake to be  an important resting place. At any time of the year, wildlife including osprey, bald eagles, mink, and kingfisher  fish in the waters of Hallam Lake. While Hallam Lake isn’t a natural feature, it has become an important part of the landscape, both to wildlife and to humans. For this reason, ACES is planning on taking steps to ensure Hallam Lake continues to exist into the foreseeable future.


Hallam Lake Today

Over the past few years, ACES has documented the continued degradation of the earthen berm that creates Hallam Lake as well as the outflow structure that drains water into the wetlands below the lake. Repair work to these structures was last done in 1988. At that time the heavy equipment doing the work got stuck and was unable to repair the back portions of the berm and the work was left incomplete. As part of ACES’ 50th Anniversary Capital Campaign, we have raised funds to finish this work and improve the rest of the berm while also improving habitat.

The Plan for Restoration

On September 20 ACES will begin work on a major habitat improvement and infrastructure repair project at Hallam Lake. The Hallam Lake Habitat Improvement and Berm Repair project has two primary goals. The first goal is to repair the earthen berm and outlet structures that create Hallam Lake, ensuring the lake persists for the foreseeable future. The second goal is to improve habitat diversity at Hallam Lake by creating additional deep sections of the lake and building new emergent wetlands along the edge of the lake.

In addition to repairing the infrastructure that maintains Hallam Lake, ACES will improve the terrestrial and aquatic habitat in and around Hallam Lake. Currently, Hallam Lake lacks structural diversity–meaning much of the lake is the same depth. Increasing structural diversity will improve aquatic habitat for fish and invertebrates, and in turn the species that feed on them. Additionally, the upper portions of Hallam Lake would benefit from an increase in wetlands adjacent to the Lake, potentially even increasing its biodiversity. Wetlands currently represent less than 3% of Colorado’s land area but benefit over 75% of native species.

A project of this scale and scope isn’t without impacts, all of which we carefully considered and weighed prior to beginning construction. In the short term, the visual appearance of Hallam Lake will be impacted. For two and a half months the lake will be drained and there will be earthmoving equipment operating in the nature preserve. During this time access to the preserve will be limited. Also during this time and following the project, we will do everything possible to preserve the ecological integrity of Hallam Lake. Many of the smaller fish will survive by hiding out in springs that continue to flow. We will move larger fish to the upper pond and off-site. Due to the timing of the work, we anticipate minimal impacts to most bird species. Birds that depend on Hallam Lake as a source of food will likely move to the Roaring Fork during this time, and once nesting season starts next spring the lake will be full again. 

Over the next several years, we’ll be focused on restoring any vegetation communities damaged to access the lake. At the end of construction, we’ll be seeding these areas, and next spring we’ll be planting over 10,000 wetland plants to help natural regeneration. Resident beavers will likely adjust and occupy lodges on some of the Hallam Lake side channels where water will remain, and wet areas adjacent to the Roaring Fork River.

Project Schedule

Starting September 20, a haul road to the pond will be constructed. Later in September, we will excavate and cobble for the earthen berm and wetlands. In October, we will replace the outflow structure and reinforce the earthen berm. In November, we will construct the emergent wetlands, as well as the middle pond wetlands and spawning channel. In December, we will remove and restore the haul road, as well as transport excess sediment. In early spring 2022, we will be starting revegetation, as directed by our Project Ecologist. During this time, all pedestrian routes and roads will remain open and unobstructed.

While Hallam Lake has served a number of cultural and ecological purposes over the years, it’s always been an important part of the Roaring Fork Valley. With the coming improvements, we hope to contribute to an even healthier ecosystem – one that will benefit the landscape in innumerable ways.

-Adam McCurdy, ACES Forest and Climate Director

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